| 1. |
- Abdeldaim, Guma, et al.
(författare)
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Is quantitative PCR for the pneumolysin (ply) gene useful for detection of pneumococcal lower respiratory tract infection?
- 2009
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 15:6, s. 565-570
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Tidskriftsartikel (refereegranskat)abstract
- The pneumolysin (ply) gene is widely used as a target in PCR assays for Streptococcus pneumoniae in respiratory secretions. However, false-positive results with conventional ply-based PCR have been reported. The aim here was to study the performance of a quantitative ply-based PCR for the identification of pneumococcal lower respiratory tract infection (LRTI). In a prospective study, fibreoptic bronchoscopy was performed in 156 hospitalized adult patients with LRTI and 31 controls who underwent bronchoscopy because of suspicion of malignancy. Among the LRTI patients and controls, the quantitative ply-based PCR applied to bronchoalveolar lavage (BAL) fluid was positive at >/=10(3) genome copies/mL in 61% and 71% of the subjects, at >/=10(5) genome copies/mL in 40% and 58% of the subjects, and at >/=10(7) genome copies/mL in 15% and 3.2% of the subjects, respectively. Using BAL fluid culture, blood culture, and/or a urinary antigen test, S. pneumoniae was identified in 19 LRTI patients. As compared with these diagnostic methods used in combination, quantitative ply-based PCR showed sensitivities and specificities of 89% and 43% at a cut-off of 10(3) genome copies/mL, of 84% and 66% at a cut-off of 10(5) genome copies/mL, and of 53% and 90% at a cut-off of 10(7) genome copies/mL, respectively. In conclusion, a high cut-off with the quantitative ply-based PCR was required to reach acceptable specificity. However, as a high cut-off resulted in low sensitivity, quantitative ply-based PCR does not appear to be clinically useful. Quantitative PCR methods for S. pneumoniae using alternative gene targets should be evaluated.
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| 2. |
- Abdeldaim, Guma M. K., et al.
(författare)
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Detection of Haemophilus influenzae in respiratory secretions from pneumonia patients by quantitative real-time polymerase chain reaction
- 2009
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier. - 0732-8893 .- 1879-0070. ; 64:4, s. 366-373
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Tidskriftsartikel (refereegranskat)abstract
- A quantitative real-time polymerase chain reaction (PCR) based on the omp P6 gene was developed to detect Haemophilus influenzae. Its specificity was determined by analysis of 29 strains of 11 different Haemophilus spp. and was compared with PCR assays having other target genes: rnpB, 16S rRNA, and bexA. The method was evaluated on nasopharyngeal aspirates from 166 adult patients with community-acquired pneumonia. When 104 DNA copies/mL was used as cutoff limit for the method, P6 PCR had a sensitivity of 97.5% and a specificity of 96.0% compared with the culture. Of 20 culture-negative but P6 PCR-positive cases, 18 were confirmed by fucK PCR as H. influenzae. Five (5.9%) of 84 nasopharyngeal aspirates from adult controls tested PCR positive. We conclude that the P6 real-time PCR is both sensitive and specific for identification of H. influenzae in respiratory secretions. Quantification facilitates discrimination between disease-causing H. influenzae strains and commensal colonization.
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| 3. |
- Abdeldaim, Guma M. K.
(författare)
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PCR detection of Streptococcus pneumoniae and Haemophilus influenzae in pneumonia patients
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- PCR is a rapid, reproducible method for nucleic acid detection. However, this technology displays significant deficiencies when applied in clinical microbiology. This work’s aim was to improve current diagnostics and provide sensitive and quantitative real-time PCRs. Paper I describes the development of a sensitive and specific quantitative real-time PCR for the detection of Streptococcus pneumoniae, based on the Spn9802 DNA fragment. Applied to nasopharyngeal aspirates from 166 pneumonia patients, Spn9802 PCR had a sensitivity of 94% and a specificity of 98%. In Paper II the performance of a ply gene PCR for identification of pneumococcal lower respiratory tract infection (LRTI) was evaluated on bronchoalveloar lavage fluids. At the detection limit 103 genome copies/mL, 89% sensitivity but only 43% specificity was achieved. Paper III shows that S. pneumoniae DNA is detectable in plasma from acutely febrile patients. Sensitivities were low (26-42%) for detection of pneumococcal pneumonia, for bacteraemic pneumococcal pneumonia they were 60-70%. Paper IV describes evaluation of four PCR targets for Haemophilus influenzae detection. A real-time PCR based on the P6 gene was developed and applied to 166 CAP patients, using cut-off of 104 genome copies/mL the assay had a sensitivity of 97% and a specificity of 96%. In paper V, the two real-time PCRs presented in papers I and IV were combined with a PCR for detection of Neisseriae meningitidis. The analytical sensitivity of this multiplex real-time PCR was not affected by using a mixture of reagents and a combined DNA standard (S. pneumoniae/H. influenzae) in single tubes. Applied to 156 LRTI patients, this PCR had sensitivities over 90% for S. pneumoniae and H. influenzae, and specificities of 89% and 96%, respectively. In conclusion, real-time PCR assays are useful for the diagnosis of S. pneumoniae and H. influenzae. They enable detection after antibiotic installation, and quantification increases the etiological specificity of pneumonia.
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| 4. |
- Abdeldaim, Guma M. K., et al.
(författare)
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Quantitative fucK gene polymerase chain reaction on sputum and nasopharyngeal secretions to detect Haemophilus influenzae pneumonia
- 2013
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier. - 0732-8893 .- 1879-0070. ; 76:2, s. 141-146
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Tidskriftsartikel (refereegranskat)abstract
- A quantitative polymerase chain reaction (PCR) for the fucK gene was developed for specific detection of Haemophilus influenzae. The method was tested on sputum and nasopharyngeal aspirate (NPA) from 78 patients with community-acquired pneumonia (CAP). With a reference standard of sputum culture and/or serology against the patient's own nasopharyngeal isolate, H. influenzae etiology was detected in 20 patients. Compared with the reference standard, fucK PCR (using the detection limit 10(5) DNA copies/mL) on sputum and NPA showed a sensitivity of 95.0% (19/20) in both cases, and specificities of 87.9% (51/58) and 89.5% (52/58), respectively. In a receiver operating characteristic curve analysis, sputum fucK PCR was found to be significantly superior to sputum P6 PCR for detection of H. influenzae CAP. NPA fucK PCR was positive in 3 of 54 adult controls without respiratory symptoms. In conclusion, quantitative fucK real-time PCR provides a sensitive and specific identification of H. influenzae in respiratory secretions.
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| 5. |
- Abdeldaim, Guma M. K., et al.
(författare)
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Toward a quantitative DNA-based definition of pneumococcal pneumonia : a comparison of Streptococcus pneumoniae target genes, with special reference to the Spn9802 fragment
- 2008
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier BV. - 0732-8893 .- 1879-0070. ; 60:2, s. 143-150
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Tidskriftsartikel (refereegranskat)abstract
- The current shift from phenotypically toward genotypically based microbial diagnosis is not unproblematic. A novel quantitative real-time polymerase chain reaction (PCR) assay based on the Spn9802 DNA fragment was therefore developed for detection of Streptococcus pneumoniae. Out of 44 bacterial species, only S. pneumoniae and Streptococcus pseudopneumoniae were positive in Spn9802 PCR. In an evaluation on nasopharyngeal aspirates from 166 patients with community-acquired pneumonia, the assay was positive in 49 of 50 culture-positive cases. Of 19 culture-negative but Spn9802 PCR-positive cases, 12 were confirmed as S. pneumoniae by rnpB sequence analysis. With an expanded reference standard, including culture and rnpB sequencing, Spn9802 had a sensitivity of 94% and a specificity of 98%. A cutoff for clinically significant positivity was 10(4) DNA copies/mL, giving 71% sensitivity and 100% specificity. In conclusion, Spn9802 real-time PCR is highly sensitive and specific. The quantification it provides enables differentiation between pneumococcal pathogenicity and commensalism.
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| 6. |
- Abdeldaim, Guma, 1969-, et al.
(författare)
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Multiplex quantitative PCR for detection of lower respiratory tract infection and meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis
- 2010
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 10, s. 310-
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Tidskriftsartikel (refereegranskat)abstract
- Background. Streptococcus pneumoniae and Haemophilus influenzae cause pneumonia and as Neisseria meningitidis they are important agents of meningitis. Although several PCR methods have been described for these bacteria the specificity is an underestimated problem. Here we present a quantitative multiplex real-time PCR (qmPCR) for detection of S. pneumoniae (9802 gene fragment), H. influenzae (omp P6 gene) and N. meningitidis (ctrA gene). The method was evaluated on bronchoalveolar lavage (BAL) samples from 156 adults with lower respiratory tract infection (LRTI) and 31 controls, and on 87 cerebrospinal fluid (CSF) samples from meningitis patients. Results. The analytical sensitivity was not affected by using a combined mixture of reagents and a combined DNA standard (S. pneumoniae/H. influenzae/N. meningitidis) in single tubes. By blood- and BAL-culture and S. pneumoniae urinary antigen test, S. pneumoniae and H. influenzae were aetiological agents in 21 and 31 of the LTRI patients, respectively. These pathogens were identified by qmPCR in 52 and 72 of the cases, respectively, yielding sensitivities and specificities of 95% and 75% for S. pneumoniae, and 90% and 65% for H. influenzae, respectively. When using a cut-off of 105 genome copies/mL for clinical positivity the sensitivities and specificities were 90% and 80% for S. pneumoniae, and 81% and 85% for H. influenzae, respectively. Of 44 culture negative but qmPCR positive for H. influenzae, 41 were confirmed by fucK PCR as H. influenzae. Of the 103 patients who had taken antibiotics prior to sampling, S. pneumoniae and H. influenzae were identified by culture in 6% and 20% of the cases, respectively, and by the qmPCR in 36% and 53% of the cases, respectively. In 87 CSF samples S. pneumoniae and N. meningitidis were identified by culture and/or 16 S rRNA in 14 and 10 samples and by qmPCR in 14 and 10 samples, respectively, giving a sensitivity of 100% and a specificity of 100% for both bacteria. Conclusions. The PCR provides increased sensitivity and the multiplex format facilitates diagnosis of S. pneumoniae, H. influenzae and N. meningitidis and the assay enable detection after antibiotic treatment has been installed. Quantification increases the specificity of the etiology for pneumonia.
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| 7. |
- Abdeldaim, Guma, et al.
(författare)
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Usefulness of real-time PCR for lytA, ply, and Spn9802 on plasma samples for the diagnosis of pneumococcal pneumonia
- 2010
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 16:8, s. 1135-1141
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we evaluated rapid real-time PCR assays for ply, Spn9802, and lytA applied to plasma samples for the detection of Streptococcus pneumoniae in patients with community-acquired pneumonia (CAP). In a prospective study of CAP aetiology, an EDTA plasma sample was collected together with blood culture in 92 adult CAP patients and 91 adult controls. Among the 92 CAP patients, lytA PCR was positive in eight (9%), Spn9802 PCR was positive in 11 (12%) and ply PCR was positive in 19 (21%) cases. Of 91 controls, the ply PCR was positive in eight cases (9%), but no positive cases were noted by Spn9802 or lytA PCRs. Ten CAP patients had pneumococcal bacteraemia. Compared to blood culture, PCR for lytA, Spn9802 and ply had sensitivities of 70% (7/10), 60% (6/10) and 70% (7/10), and specificities of 96% (79/82), 94% (77/82) and 85% (70/82) respectively. With blood culture and/or culture of representative sputum, and/or urinary antigen detection, S. pneumoniae was identified in 31 CAP patients. Compared to these tests in combination, PCR for lytA, Spn9802 and ply showed sensitivities of 26% (8/31), 32% (10/31) and 42% (13/31), and specificities of 100% (61/61), 98% (60/61) and 90% (55/61) respectively. We conclude that Spn9802 and lytA PCRs may be useful for the rapid detection of bacteraemic pneumococcal pneumonia, whereas ply PCR is not specific enough for routine use and blood PCR with small plasma volumes is not useful for the detection of nonbacteraemic pneumococcal pneumonia.
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| 8. |
- Alpkvist, Helena, et al.
(författare)
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Clinical and Microbiological Factors Associated with High Nasopharyngeal Pneumococcal Density in Patients with Pneumococcal Pneumonia
- 2015
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Ingår i: PLOS ONE. - : Public Library Science. - 1932-6203. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: We aimed to study if certain clinical and/or microbiological factors are associated with a high nasopharyngeal (NP) density of Streptococcus pneumoniae in pneumococcal pneumonia. In addition, we aimed to study if a high NP pneumococcal density could be useful to detect severe pneumococcal pneumonia.Methods: Adult patients hospitalized for radiologically confirmed community-acquired pneumonia were included in a prospective study. NP aspirates were collected at admission and were subjected to quantitative PCR for pneumococcal DNA (Spn9802 DNA). Patients were considered to have pneumococcal etiology if S. pneumoniae was detected in blood culture and/ or culture of respiratory secretions and/or urinary antigen test.Results: Of 166 included patients, 68 patients had pneumococcal DNA detected in NP aspirate. Pneumococcal etiology was noted in 57 patients (84%) with positive and 8 patients (8.2%) with negative test for pneumococcal DNA (p<0.0001). The median NP pneumococcal density of DNA positive patients with pneumococcal etiology was 6.83 log(10) DNA copies/mL (range 1.79-9.50). In a multivariate analysis of patients with pneumococcal etiology, a high pneumococcal density was independently associated with severe pneumonia (Pneumonia Severity Index risk class IV-V), symptom duration >= 2 days prior to admission, and a medium/high serum immunoglobulin titer against the patient's own pneumococcal serotype. NP pneumococcal density was not associated with sex, age, smoking, co-morbidity, viral co-infection, pneumococcal serotype, or bacteremia. Severe pneumococcal pneumonia was noted in 28 study patients. When we studied the performance of PCR with different DNA cut-off levels for detection of severe pneumococcal pneumonia, we found sensitivities of 54-82% and positive predictive values of 37-56%, indicating suboptimal performance.Conclusions: Pneumonia severity, symptom duration similar to 2 days, and a medium/high serum immunoglobulin titer against the patient's own serotype were independently associated with a high NP pneumococcal density. NP pneumococcal density has limited value for detection of severe pneumococcal pneumonia.
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| 9. |
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| 10. |
- Athlin, Simon, 1971-, et al.
(författare)
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Association between serotype-specific antibody response and serotype characteristics in patients with pneumococcal pneumonia, with special reference to degree of encapsulation and invasive potential
- 2014
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Ingår i: Clinical and Vaccine Immunology. - : American Society for Microbiology. - 1556-6811 .- 1556-679X. ; 21:11, s. 1541-1549
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Tidskriftsartikel (refereegranskat)abstract
- We studied the immunoglobulin (Ig) response to causative serotype-specific capsular polysaccharides in adult pneumococcal pneumonia patients. The serotypes were grouped according to their degree of encapsulation and invasive potential. Seventy patients with pneumococcal pneumonia, 20 of whom were bacteremic, were prospectively studied. All pneumococcal isolates from the patients were serotyped, and the Ig titers to the homologous serotype were determined in acute- and convalescent-phase sera using a serotype-specific enzyme-linked immunosorbent assay. The Ig titers were lower in bacteremic cases than in nonbacteremic cases (P < 0.042). The Ig titer ratio (convalescent/acute titer) was ≥2 in 33 patients, 1 to 1.99 in 20 patients, and <1 in 17 patients. Patients ≥65 years old had a lower median Ig titer ratio than did younger patients (P < 0.031). The patients with serotypes with a thin capsule (1, 4, 7F, 9N, 9V, and 14) and medium/high invasive potential (1, 4, 7F, 9N, 9V, 14, and 18C) had higher Ig titer ratios than did patients with serotypes with a thick capsule (3, 6B, 11A, 18C, 19A, 19F, and 23F) and low invasive potential (3, 6B, 19A, 19F, and 23F) (P < 0.05 for both comparisons after adjustment for age). Ig titer ratios of <1 were predominantly noted in patients with serotypes with a thick capsule. In 8 patients with pneumococcal DNA detected in plasma, the three patients with the highest DNA load had the lowest Ig titer ratios. In conclusion, a high antibody response was associated with serotypes with a thin capsule and medium/high invasive potential, although a low antibody response was associated with serotypes with a thick capsule and a high pneumococcal plasma load.
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| 11. |
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| 12. |
- Athlin, Simon, 1971-, et al.
(författare)
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Management of community-acquired pneumonia in immunocompetent adults : updated Swedish guidelines 2017
- 2018
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 50:4, s. 247-272
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Forskningsöversikt (refereegranskat)abstract
- Based on expert group work, Swedish recommendations for the management of community-acquired pneumonia in adults are here updated. The management of sepsis-induced hypotension is addressed in detail, including monitoring and parenteral therapy. The importance of respiratory support in cases of acute respiratory failure is emphasized. Treatment with high-flow oxygen and non-invasive ventilation is recommended. The use of statins or steroids in general therapy is not found to be fully supported by evidence. In the management of pleural infection, new data show favourable effects of tissue plasminogen activator and deoxyribonuclease installation. Detailed recommendations for the vaccination of risk groups are afforded.
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| 13. |
- Athlin, Simon, 1971-, et al.
(författare)
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Pneumococcal urinary antigen testing for antimicrobial guidance in community-acquired pneumonia : A register-based cohort study
- 2022
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Ingår i: Journal of Infection. - : Elsevier. - 0163-4453 .- 1532-2742. ; 85:2, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the effect of pneumococcal urinary antigen test (UAT) usage on broad-spectrum antibiotic treatment in community-acquired pneumonia (CAP).METHODS: Patients admitted to 32 Swedish hospitals between 2011 and 2014 were retrospectively included from the Swedish National Quality Register of CAP. Using propensity score matched data, stratified by CRB-65 score, we studied the effect of performing UAT and of positive test results on treatment with broad-spectrum β-lactam monotherapy (BSBM) and antibiotics with coverage for atypical bacteria compared to narrow-spectrum β-lactam monotherapy (NSBM).RESULTS: UAT was performed for 4,995/14,590 (34.2%) patients, 603/4,995 (12.1%) of whom had positive test results. At day three, performing UAT was not associated with decreased use of BSBM (OR 1.07, 95% CI 0.94-1.23) but was associated with increased atypical coverage among patients with CRB-65 score 2 (OR 1.47, 95% CI 1.06-2.02). A positive UAT was associated with decreased BSBM use (OR 0.39, 95% CI 0.25-0.60) and decreased atypical coverage (OR 0.25, 95% CI 0.16-0.37), predominantly in non-severe CAP. At day one, performing UAT was associated with atypical coverage among patients with CRB-65 scores 2 (OR 2.60, 95% CI 1.69-3.98) and 3-4 (OR 3.69, 95% CI 1.55-8.79), and a positive test reduced the odds of BSBM treatment among CRB-65 score 3-4 patients (OR 3.49, 95% CI 1.02-12.0).CONCLUSIONS: Performing UAT had no overall effect on decreasing the use of BSBM treatment by day three of hospitalization, yet non-severely ill patients with positive UAT results were less likely to be treated with BSBM and antibiotics with atypical coverage.
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| 14. |
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| 15. |
- Athlin, Simon, 1971-, et al.
(författare)
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The Binax NOW Streptococcus pneumoniae test applied on nasopharyngeal aspirates to support pneumococcal aetiology in community-acquired pneumonia.
- 2013
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 45:6, s. 425-31
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The use of nasopharyngeal secretions to enhance diagnostic yields of pneumococcal aetiology in community-acquired pneumonia (CAP) is of interest. We evaluated the Binax NOW Streptococcus pneumoniae immunochromatographic test (ICT) on nasopharyngeal aspirates (NPA) in order to support pneumococcal aetiology in CAP.METHODS: The NPA ICT was applied on 180 adult CAP patients and 64 healthy controls. The rate of pneumococcal detection in the nasopharynx was compared to rates for lytA polymerase chain reaction (PCR) and culture on NPA.RESULTS: According to blood and sputum culture and urine ICT, the test sensitivity in 59 patients with a pneumococcal aetiology was 81%. The specificity was suboptimal, with 72% negative tests among CAP patients without a pneumococcal aetiology. However, the test was positive in only 11% of patients with atypical pneumonia and in 4.7% of healthy controls. The positivity rate was higher for NPA ICT compared to culture on NPA in all CAP patients, and to both PCR and culture on NPA in non-pneumococcal non-atypical CAP patients. In 113 (63%) patients with β-lactam monotherapy, cure without treatment alteration was noted more often in cases with positive compared to negative NPA ICT at admission (91% vs 69%; p < 0.01).CONCLUSIONS: The high sensitivity and the low positivity rates in patients with atypical pneumonia and healthy controls, in combination with the correlation between positive test results and clinical cure with β-lactam therapy, may support a pneumococcal aetiology in CAP in populations with low pneumococcal carriage rates.
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| 16. |
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| 17. |
- Cajander, Sara, 1980-
(författare)
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Dynamics of Human Leukocyte Antigen-D Related expression in bacteremic sepsis
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Monocytic human leukocyte antigen-D related (mHLA-DR) expression determined by flow cytometry has been suggested as a biomarker of sepsisinduced immunosuppression.In order to facilitate use of HLA-DR in clinical practice, a quantitative real-time PCR technique measuring HLA-DR at the transcription level was developed and evalutated. Levels of HLA-DR mRNA correlated to mHLADR expression and were robustly measured, with high reproducibility, during the course of infection. Dynamics of mHLA-DR expression was studied during the first weeks of bloodstream infection (BSI) and was found to be dependent on the bacterial etiology of BSI. Moreover, mHLA-DR was shown to be inversely related to markers of inflammation. In patients with unfavourable outcome, sustained high C-reactive protein level and high neutrophil count were demonstrated along with low mHLA-DR expression and low lymphocyte count. This supports the theory of sustained inflammation in sepsis-induced immunosuppression. The association between mHLA-DR and bacterial etiology may be linked to the clinical trajectory via differences in ability to cause intractable infection. Staphylococcus aureus was the dominating etiology among cases with unfavourable outcome. With focus on patients with S. aureus BSI, those with complicated S. aureus BSI were found to have lower HLA-DR mRNA expression during the first week than those with uncomplicated S. aureus BSI. If these results can be confirmed in a larger cohort, HLA-DR measurement could possibly become an additional tool for early identification of patients who require further investigation to clear infectious foci and achieve source control.In conclusion, PCR-based measurement of HLA-DR is a promising method for measurements of the immune state in BSI, but needs further evaluation in the intensive care unit setting to define the predictive and prognostic value for deleterious immunosuppression. The etiology of infection should be taken into consideration in future studies of translational immunology in sepsis.
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| 18. |
- Cajander, Sara, 1980-, et al.
(författare)
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Dynamics of monocytic HLA-DR expression differs between bacterial etiologies during the course of bloodstream infection
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In the pathogenesis of sepsis, activation of both pro- and anti-inflammatory responses are key components, but knowledge is lacking on the association between bacterial etiology and development of dysregulated responses with sustained immunosuppression. The aim of this study was to evaluate how the immunosupression marker HLA-DR on monocytes (mHLA-DR) is associated with bacterial etiology and markers of inflammation during the clinical trajectory of bloodstream infection (BSI).METHODS: Ninety-one adults, predominantly non-ICU patients, with BSI caused by Streptococcus pneumoniae (n = 27), Staphylococcus aureus (n = 22), Escherichia coli/Klebsiella pneumoniae (n = 23), and other species (n = 19) were prospectively included, and sampled on admission (day 0) and on days 1-2, 3, 7±1, 14±2, and 28±4.RESULTS: The dynamics of mHLA-DR, measured by flow cytometry, differed significantly between etiology groups (p<0.001). Patients with S. pneumoniae and S. aureus BSI demonstrated low initial mHLA-DR, with the S. aureus group showing delayed recovery over time. Eleven patients (55% S. aureus) had negative outcome (secondary bacteremia or death) and they demonstrated sustained C-reactive protein elevation, neutrophilia, lymphocytopenia, and loss of mHLA-DR.CONCLUSIONS: Dynamics of mHLA-DR varied according to the bacterial etiology of infection, with delayed recovery in patients with S. aureus BSI. Patients with negative outcome showed sustained CRP elevation, neutrophilia, lymphocytopenia, and low levels of mHLA-DR, supporting the theory of a dysregulated host response with persistent inflammation and immunosuppression in late stages of deleterious sepsis.
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| 19. |
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| 20. |
- Cajander, Sara, 1980-, et al.
(författare)
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Preliminary results in quantitation of HLA-DRA by real-time PCR : a promising approach to identify immunosuppression in sepsis
- 2013
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Ingår i: Critical Care. - London, United Kingdom : BioMed Central. - 1364-8535 .- 1466-609X. ; 17:5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Reduced monocyte human leukocyte antigen (mHLA)-DR surface expression in the late phase of sepsis is postulated as a general biomarker of sepsis-induced immunosuppression and an independent predictor of nosocomial infections. However, traditional monitoring of mHLA-DR by flow cytometry has disadvantages due to specific laboratory requirements. An mRNA-based HLA-DR monitoring by polymerase chain reaction (PCR) would improve the clinical usage and facilitate conduction of large multicenter studies. In this study, we evaluated an mRNA-based HLA-DR monitoring by quantitative real-time PCR (qRT-PCR) as an alternative method to traditional flow cytometry.Methods: Fifty-nine patients with sepsis and blood culture growing pathogenic bacteria were studied. Blood samples were collected at day 1 or 2 after admission, for measurement of mHLA-DR by flow cytometry and mRNA expression of HLA-DRA and class II transactivator (CIITA) by qRT-PCR. Blood samples from blood donors were used as controls (n = 30).Results: A significant reduced expression of mHLA-DR, HLA-DRA, and CIITA was seen in septic patients compared with controls. HLA-DRA mRNA level in whole blood was highly correlated with surface expression of mHLA-DR.Conclusions: Patients with sepsis display a diminished expression of HLA-DR at the monocyte surface as well as in the gene expression at the mRNA level. The mRNA expression level of HLA-DRA monitored by qRT-PCR correlates highly with surface expression of HLA-DR and appears to be a possible future biomarker for evaluation of immunosuppression in sepsis.
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| 21. |
- Cajander, Sara, 1980-, et al.
(författare)
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Quantitative Real-Time Polymerase Chain Reaction Measurement of HLA-DRA Gene Expression in Whole Blood Is Highly Reproducible and Shows Changes That Reflect Dynamic Shifts in Monocyte Surface HLA-DR Expression during the Course of Sepsis
- 2016
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Ingår i: PLOS ONE. - San Francisco, USA : Public Library of Science. - 1932-6203. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A decrease in the expression of monocyte surface protein HLA-DR (mHLA-DR), measured by flow cytometry (FCM), has been suggested as a marker of immunosuppression and negative outcome in severe sepsis. However, FCM is not always available due to sample preparation that limits its use to laboratory operational hours. In this prospective study we evaluated dynamic changes in mHLA-DR expression during sepsis in relation to changes in HLA-DRA gene expression and Class II transactivator (CIITA), measured by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR).Aims: The aims of this study were: 1. to validate the robustness of qRT-PCR measurement of HLA-DRA- and CIITA-mRNA expression, in terms of reproducibility; and 2. to see if changes in expression of these genes reflect changes in mHLA-DR expression during the course of severe and non-severe bacteraemic sepsis.Methods and Findings: Blood samples were collected from 60 patients with bacteraemic sepsis on up to five occasions during Days 1-28 after hospital admission. We found the reproducibility of the qRT-PCR method to be high by demonstrating low threshold variations (<0.11 standard deviation (SD)) of the qRT-PCR system, low intra-assay variation of Ct-values within triplicates (≤0.15 SD) and low inter-assay variations (12%) of the calculated target gene ratios. Our results also revealed dynamic HLA-DRA expression patterns during the course of sepsis that reflected those of mHLA-DR measured by FCM. Furthermore, HLA-DRA and mHLA-DR recovery slopes in patients with non-severe sepsis differed from those in patients with severe sepsis, shown by mixed model for repeated measurements (p<0.05). However, during the first seven days of sepsis, PCR-measurements showed a higher magnitude of difference between the two sepsis groups. Mean differences (95% CI) between severe sepsis (n = 20) and non-severe sepsis (n = 40) were; on day 1-2, HLA-DRA 0.40 (0.28-0.59) p<0.001, CIITA 0.48 (0.32-0.72) p = 0.005, mHLA-DR 0.63 (0.45-1.00) p = 0.04, day 7 HLA-DRA 0.59 (0.46-0.77) p<0.001, CIITA 0.56 (0.41-0.76) p<0.001, mHLA-DR 0.81 (0.66-1.00) p = 0.28.Conclusion: We conclude that qRT-PCR measurement of HLA-DRA expression is robust, and that this method appears to be preferable to FCM in identifying patients with severe sepsis that may benefit from immunostimulation.
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| 22. |
- Karlsson Valik, John, et al.
(författare)
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Peripheral Oxygen Saturation Facilitates Assessment of Respiratory Dysfunction in the Sequential Organ Failure Assessment Score With Implications for the Sepsis-3 Criteria
- 2022
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Ingår i: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 50:3, s. e272-e283
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Sequential Organ Failure Assessment score is the basis of the Sepsis-3 criteria and requires arterial blood gas analysis to assess respiratory function. Peripheral oxygen saturation is a noninvasive alternative but is not included in neither Sequential Organ Failure Assessment score nor Sepsis-3. We aimed to assess the association between worst peripheral oxygen saturation during onset of suspected infection and mortality.DESIGN: Cohort study of hospital admissions from a main cohort and emergency department visits from four external validation cohorts between year 2011 and 2018. Data were collected from electronic health records and prospectively by study investigators.SETTING: Eight academic and community hospitals in Sweden and Canada.PATIENTS: Adult patients with suspected infection episodes.INTERVENTIONS: None.MEASUREMENTS AND MAIN RESULTS: The main cohort included 19,396 episodes (median age, 67.0 [53.0–77.0]; 9,007 [46.4%] women; 1,044 [5.4%] died). The validation cohorts included 10,586 episodes (range of median age, 61.0–76.0; women 42.1–50.2%; mortality 2.3–13.3%). Peripheral oxygen saturation levels 96–95% were not significantly associated with increased mortality in the main or pooled validation cohorts. At peripheral oxygen saturation 94%, the adjusted odds ratio of death was 1.56 (95% CI, 1.10–2.23) in the main cohort and 1.36 (95% CI, 1.00–1.85) in the pooled validation cohorts and increased gradually below this level. Respiratory assessment using peripheral oxygen saturation 94–91% and less than 91% to generate 1 and 2 Sequential Organ Failure Assessment points, respectively, improved the discrimination of the Sequential Organ Failure Assessment score from area under the receiver operating characteristics 0.75 (95% CI, 0.74–0.77) to 0.78 (95% CI, 0.77–0.80; p < 0.001). Peripheral oxygen saturation/Fio2 ratio had slightly better predictive performance compared with peripheral oxygen saturation alone, but the clinical impact was minor.CONCLUSIONS: These findings provide evidence for assessing respiratory function with peripheral oxygen saturation in the Sequential Organ Failure Assessment score and the Sepsis-3 criteria. Our data support using peripheral oxygen saturation thresholds 94% and 90% to get 1 and 2 Sequential Organ Failure Assessment respiratory points, respectively. This has important implications primarily for emergency practice, rapid response teams, surveillance, research, and resource-limited settings.
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| 23. |
- Kauppi, Anna M., et al.
(författare)
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Metabolites in Blood for Prediction of Bacteremic Sepsis in the Emergency Room
- 2016
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Ingår i: PLOS ONE. - : Public Library Science. - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- A metabolomics approach for prediction of bacteremic sepsis in patients in the emergency room (ER) was investigated. In a prospective study, whole blood samples from 65 patients with bacteremic sepsis and 49 ER controls were compared. The blood samples were analyzed using gas chromatography coupled to time-of-flight mass spectrometry. Multivariate and logistic regression modeling using metabolites identified by chromatography or using conventional laboratory parameters and clinical scores of infection were employed. A predictive model of bacteremic sepsis with 107 metabolites was developed and validated. The number of metabolites was reduced stepwise until identifying a set of 6 predictive metabolites. A 6-metabolite predictive logistic regression model showed a sensitivity of 0.91(95% CI 0.69-0.99) and a specificity 0.84 (95% CI 0.58-0.94) with an AUC of 0.93 (95% CI 0.89-1.01). Myristic acid was the single most predictive metabolite, with a sensitivity of 1.00 (95% CI 0.85-1.00) and specificity of 0.95 (95% CI 0.74-0.99), and performed better than various combinations of conventional laboratory and clinical parameters. We found that a metabolomics approach for analysis of acute blood samples was useful for identification of patients with bacteremic sepsis. Metabolomics should be further evaluated as a new tool for infection diagnostics.
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| 24. |
- Lange, Anna, 1975-, et al.
(författare)
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Plasma concentrations of secretory leukocyte protease inhibitor (SLPI) differ depending on etiology and severity in community-onset bloodstream infection
- 2019
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer. - 0934-9723 .- 1435-4373. ; 38:8, s. 1425-1434
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Tidskriftsartikel (refereegranskat)abstract
- The severity of bloodstream infections (BSI) depends on pathogen, source, and host factors. Secretory leukocyte protease inhibitor (SLPI) counteracts tissue damage, balances inflammation, and is increased in pneumonia and sepsis. We aimed to evaluate whether SLPI production differs depending on etiology, disease severity, and sex in BSI and to correlate SLPI with markers of inflammation and immunosuppression. Of the adult patients with BSI, 109 were included and sampled repeatedly, from hospital admission through day 28. Controls (blood donors) were sampled twice. SLPI in plasma was measured with enzyme-linked immunosorbent assay (ELISA) technique. Streptococcus pneumoniae and Staphylococcus aureus etiology were associated with higher SLPI than Escherichia coli on days 1-2 and 3. On day 1-2, subjects with sepsis had higher SLPI concentrations than those with non-septic BSI. Pneumonia was associated with higher SLPI than a non-pulmonary source of infection. SLPI co-varied with inflammatory markers. SLPI concentrations did not differ with regard to sex in the full cohort, but men with pneumonia had higher SLPI than women on day 1-2. S. pneumoniae and S. aureus BSI were associated with higher SLPI, when compared to E. coli. Severity and pneumonia, as well as male sex in the pneumonia sub-cohort, were factors independently associated with higher SLPI.
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| 25. |
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| 26. |
- Lange, Anna, 1975-, et al.
(författare)
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Sustained elevation of soluble B- and T- lymphocyte attenuator predicts long-term mortality in patients with bacteremia and sepsis
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 17:3
-
Tidskriftsartikel (refereegranskat)abstract
- Soluble B and T lymphocyte attenuator (sBTLA) has been shown to be associated with severity and outcome, in critically ill septic patients. We aimed to assess the dynamic expression of sBTLA, as a prognostic biomarker of long-term mortality in patients with bloodstream infection (BSI) and sepsis, and to evaluate its association with biomarkers indicative of inflammation and immune dysregulation. Secondarily, sBTLA was evaluated in association with severity and bacterial etiology. Patients with BSI (n = 108) were prospectively included, and serially sampled from admission to day 28. Blood and plasma donors (n = 31), sampled twice 28 days apart, served as controls. sBTLA concentration in plasma was determined with enzyme-linked immunosorbent assay. Associations between sBTLA on day 1-2 and 7, and mortality at 90 days and 1 year, were determined with unadjusted, and adjusted Cox regression. Differences related to severity was assessed with linear regression. Mixed model was used to assess sBTLA dynamics over time, and sBTLA associations with bacterial etiology and other biomarkers. sBTLA on day 1-2 and 7 was associated with mortality, in particular failure to normalize sBTLA by day 7 was associated with an increased risk of death before day 90, adjusted HR 17 (95% CI 1.8-160), and one year, adjusted HR 15 (95% CI 2.8-76). sBTLA was positively associated with CRP, and negatively with lymphocyte count. sBTLA on day 1-2 was not linearly associated with baseline SOFA score increase. High SOFA (≥4) was however associated with higher mean sBTLA than SOFA ≤3. sBTLA was not associated with bacterial etiology. We show that sustained elevation of sBTLA one week after hospital admission is associated with late mortality in patients with BSI and sepsis, and that sBTLA concentration is associated with CRP and decreased lymphocyte count. This suggests that sBTLA might be an indicator of sustained immune-dysregulation, and a prognostic tool in sepsis.
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| 27. |
- Lange-Jendeberg, Anna, 1975-, et al.
(författare)
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Antimicrobial peptide plasma concentrations in patients with community-acquired pneumonia
- 2013
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 45:6, s. 432-437
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Tidskriftsartikel (refereegranskat)abstract
- Background: Community-acquired pneumonia (CAP) is a common and potentially life-threatening infection. Innate immunity is the first line of defence, and antimicrobial peptides (AMPs) produced by white blood cells and at epithelial barriers participate by killing microorganisms and neutralizing bacterial toxins. We wanted to investigate whether concentrations of AMPs (1) are increased in CAP, (2) predict the clinical outcome, and (3) differ depending on the causative microbe. Methods: Plasma concentrations of AMPs were measured using an enzyme-linked immunosorbent assay in 89 patients with CAP, 21 patients with non-respiratory tract infections (non-RTI), and 63 healthy control subjects. Results: In subjects with CAP, mean plasma concentrations of secretory leukocyte protease inhibitor (SLPI) and bactericidal/permeability-increasing protein (BPI) were significantly higher than in healthy control subjects (85 vs 45 ng/ml, p < 0.001 and 48 vs 10 ng/ml, p < 0.001, respectively), but less markedly increased in patients with non-RTI (68 ng/ml, p = 0.06 and 41 ng/ml, p = 0.43). LL-37 and human neutrophil peptides 1-3 (HNP 1-3) levels were not increased in subjects with CAP. Levels of BPI and SLPI did not correlate to severity of disease, and AMP levels did not differ depending on the causative agent. Interestingly, male subjects with CAP displayed increased concentrations of SLPI compared to females. This was not observed in subjects with non-RTI and healthy control subjects. Conclusions: Subjects with CAP showed increased plasma concentrations of SLPI and BPI compared to healthy control subjects. The finding of higher SLPI levels in male subjects with CAP implies that there are sex-dependent immunological differences in SLPI turnover.
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| 28. |
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| 29. |
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| 30. |
- Rasmussen, Gunlög, et al.
(författare)
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Caspase-1 Inflammasome Activity in Patients with Staphylococcus aureus Bacteremia
- 2019
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Ingår i: Microbiology and immunology. - : Wiley-Blackwell Publishing Inc.. - 0385-5600 .- 1348-0421. ; 63:12, s. 487-499
-
Tidskriftsartikel (refereegranskat)abstract
- The inflammasome is a multiprotein complex that mediates caspase-1 activation with subsequent maturation of the pro-inflammatory cytokines IL-1β and IL-18. The NLRP3 inflammasome is known to be activated by Staphylococcus aureus, one of the leading causes of bacteremia worldwide. Inflammasome activation and regulation in response to bacterial infection have been found to be of importance for a balanced host immune response. However, inflammasome signaling in vivo in humans initiated by S. aureus is currently sparsely studied. The present study therefore aimed to investigate NLRP3 inflammasome activity in 20 S. aureus bacteremia patients, by repeated measurement during the first week of bacteremia, compared with controls. Caspase-1 activity was measured in monocytes and neutrophils by flow cytometry detecting FLICA (Fluorescent Labelled Inhibitor of Caspase-1), while IL-1β and IL-18 was measured by Luminex and ELISA, respectively. As a measure of inflammasome priming, mRNA expression of NLRP3, CASP1 (pro-caspase-1) and IL1B (pro-IL-1β) was analyzed by qPCR. We found induced caspase-1 activity in innate immune cells with subsequent release of IL-18 in patients during the acute phase of bacteremia, indicating activation of the inflammasome. There was substantial inter-individual variation in caspase-1 activity between S. aureus bacteremia patients. We also found an altered inflammasome priming with low mRNA levels of NLRP3 accompanied by elevated mRNA levels of IL1B. This increased knowledge of the individual host immune response in S. aureus bacteremia could provide support in the effort to optimize management and treatment of each individual patient.
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| 31. |
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| 32. |
- Rasmussen, Gunlög, 1973-, et al.
(författare)
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Expression of HLA-DRA and CD74 mRNA in whole blood during the course of complicated and uncomplicated Staphylococcus aureus bacteremia
- 2017
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Ingår i: Microbiology and immunology. - : Wiley-Blackwell Publishing Asia. - 0385-5600 .- 1348-0421. ; 61:10, s. 442-451
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Tidskriftsartikel (refereegranskat)abstract
- To improve management of Staphylococcus aureus bacteremia (SAB), better understanding of host-pathogen interactions is needed. In vitro studies have shown that S. aureus bacteria induce dose-dependent immunosuppression that is evidenced by reduced expression of major histocompatibility complex (MHC) class II on antigen presenting cells. Thus, the aim of this study was to determine whether expression of the MHC class II-related genes HLA-DRA and CD74 is more greatly reduced in complicated SAB, with its probable higher loads of S. aureus, than in uncomplicated SAB. Adult patients with SAB were prospectively included and blood samples taken on the day of confirmation of SAB (Day 1) and on Days 2, 3, 5 and 7. HLA-DRA and CD74 mRNA expression was determined by quantitative reverse transcription PCR. Sepsis was defined according to the Sepsis-3 classification and SAB was categorized as complicated in patients with deep-seated infection and/or hematogenous seeding. Twenty patients with SAB were enrolled and samples obtained on all assessment days. HLA-DRA and CD74 expression did not differ significantly between patients with SAB and sepsis (n=13) and those without sepsis (n=7) on any assessment day. However, patients with complicated SAB (n=14) had significantly weaker HLA-DRA expression on all five assessment days than patients with uncomplicated SAB (n=6). Additionally, they tended to have weaker CD74 expressions. Neutrophil, monocyte and leukocyte counts did not differ significantly between complicated and uncomplicated SAB. In conclusion, patients with complicated SAB show weaker HLA-DRA expression than those with uncomplicated SAB during the first week of bacteremia.
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| 33. |
- Rasmussen, Gunlög, 1973-
(författare)
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Staphylococcus aureus bacteremia, molecular epidemiology and host immune response
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Staphylococcus aureus is a major pathogen responsible for a considerable disease burden worldwide. It may cause a wide array of infections, from superficial skin infections to invasive bacteremia and complications such as infective endocarditis (IE) and osteomyelitis. This thesis aimed to investigate aspects of the molecular epidemiology of S. aureus and host immune response in relation to disease manifestation, severity, and over time during S. aureus bacteremia (SAB).Genotypic characteristics in isolates causing colonization, bacteremia, and bacteremia with IE were studied. The S. aureus population was genetically diverse and certain clones with their set of often lineage-specific virulence genes were associated with invasive disease. Characterization of the long-term molecular epidemiology of MSSA bacteremia showed an increased prevalence of CC5 and CC15, while CC8, CC25 and CC30 declined. Antibiotic resistance pattern was favorable and unaffected.Further, different aspects of host immune response were explored in patients with SAB during the acute phase of bacteremia. When investigating the NLRP3 inflammasome signaling, induced caspase-1 activity was found, with a great inter-individual variation between patients, and subsequent release of IL-18, indicating inflammasome activity. Finally, the dynamics of MHC class II related genes HLA-DRA and CD74 were analyzed as markers of immunosuppression. Patients with complicated SAB had significantly lower HLA-DRA expression than patients with uncomplicated bacteremia, demonstrating an association between complicated SAB and impaired immune function.In conclusion, the S. aureus genotype, as well as host factors reflected by inter-individual variations in inflammasome signaling and immune function, may all contribute to disease manifestation and outcome during SAB. An ability to measure the immune response early and continuously during the hospital stay and course of bacteremia could offer a way to tailor patient management and treatment in an individualized way.
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| 34. |
- Skorup, Paul
(författare)
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Antibacterial Effect and Inflammatory Response in Relation to Antibiotic Treatment of Sepsis
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sepsis defines as life-threatening organ dysfunction caused by a dysregulated host response to infection. The importance of early administration of antibiotics in septic shock is undisputed, but the optimal antibiotic choice remains uncertain. Some national guidelines advocate single β-lactam antibiotic treatment while others recommend a combination of β-lactam and aminoglycoside. This thesis aimed to investigate the anti-bacterial properties and antibiotic-induced inflammatory responses of ß-lactam antibiotic compared with effects of the addition of an aminoglycoside in clinically relevant E. coli porcine intensive care sepsis/septic shock models. We also studied the host's antibacterial capacities in primary and secondary sepsis.In Paper I the addition of an aminoglycoside, in comparison with single β-lactam antibiotic treatment, caused decreased bacterial growth in the liver and greater antibiotic-induced blood killing activity ex vivo. The results thereby constitute possible mechanisms to the previously reported improved survival in the most critically ill sepsis patients receiving the β-lactam/aminoglycoside combination. Also observed in this paper was that individual blood bactericidal capacity may have significant effects on antimicrobial outcome. In Paper II we investigated endotoxin release in vivo after antibiotic treatment in comparison with no treatment. There were no differences, however, antibiotics did increase an inflammatory IL-6 response that was associated with leukocyte activation and pulmonary organ dysfunction. A secondary finding was that the addition of an aminoglycoside to a β-lactam induced trends towards less inflammation compared with β-lactam alone.Paper III compared how challenge with different pre-killed E. coli activates the inflammatory response, resulting in higher cytokine responses, more leucocyte activation and inflammatory capillary leakage after single β-lactam compared with live or heat-killed bacteria. The addition of an aminoglycoside lowered the β-lactam-induced responses.Paper IV demonstrated that animals with secondary sepsis exhibited an attenuated inflammatory response as expected; however, contrary to our hypothesis, the animals’ antibacterial capacities were intact and partly enhanced.We conclude that there are likely several beneficial effects of the addition of an aminoglycoside to a β-lactam therapy regimen in septic shock. Because host antibacterial capacities in secondary sepsis are enhanced, the need for bactericidal antibiotic combinations is not greater in secondary than in primary sepsis.
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| 35. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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An outbreak of primary pneumonic tularemia.
- 2002
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 346, s. 1027-1029
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Tidskriftsartikel (refereegranskat)
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| 36. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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Antibody response to the patient's own Haemophilus influenzae isolate can support the aetiology in lower respiratory tract infections
- 2004
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 112:4-5, s. 299-303
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Tidskriftsartikel (refereegranskat)abstract
- In order to understand the clinical importance of Haemophilus influenzae isolated from sputum samples, an indirect immunofluorescence (IF) assay was developed, using the patient's own isolate as the antigen. The method was tested on samples from six patients with lower respiratory tract infection (LRTI) and H. influenzae isolated from blood (n=2), sputum (n=3) or both (n=1), and on two healthy adults with H. influenzae isolated from the nasopharynx. Between acute and convalescent sera, a four-fold IgG antibody increase was achieved in five of six LRTI patients, including the three blood culture-positive patients. One LRTI patient and the two asymptomatic carriers showed stable antibody levels against their own isolate. Although small, the study indicates that indirect IF can be a promising tool for determining whether a H. influenzae strain represents the probable cause of infection or just a strain colonising the airways. More extensive studies should be performed in order to establish the usefulness of the assay.
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| 37. |
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| 38. |
- Strålin, Kristoffer, et al.
(författare)
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Comparison of Sputum and Nasopharyngeal Aspirate Samples and of the PCR Gene Targets lytA and Spn9802 for Quantitative PCR for Rapid Detection of Pneumococcal Pneumonia
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:1, s. 83-89
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to compare sputum and nasopharyngeal aspirate (NpA) samples and the PCR gene targets lytA and Spn9802 in quantitative PCR (qPCR) assays for rapid detection of pneumococcal etiology in community-acquired pneumonia (CAP). Seventy-eight adult patients hospitalized for radiologically confirmed CAP had both good-quality sputum and NpA specimens collected at admission. These samples were subjected to lytA qPCR and Spn9802 qPCR assays with analytical times of < 3 h. Thirty-two patients had CAP with a pneumococcal etiology, according to conventional diagnostic criteria. The following qPCR positivity rates were noted in CAP cases with and without pneumococcal etiology: 96% and 15% (sputum lytA assay), 96% and 17% (sputum Spn9802 assay), 81% and 11% (NpA lytA assay), and 81% and 20% (NpA Spn9802 assay), respectively. The mean lytA and Spn9802 DNA levels were significantly higher in qPCR-positive sputum samples from cases with pneumococcal etiology than in qPCR-positive sputum samples from CAP cases without pneumococcal etiology or qPCR-positive NpA samples from cases with pneumococcal etiology (P < 0.02 for all comparisons). For detection of pneumococcal etiology, receiver operating characteristic curve analysis showed that sputum specimens were superior to NpA specimens as the sample type (P < 0.02 for both gene targets) and lytA tended to be superior to Spn9802 as the gene target. The best-performing test, the sputum lytA qPCR assay, showed high sensitivity (94%) and specificity (96%) with a cutoff value of 10(5) DNA copies/ml. In CAP patients with good sputum production,
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| 39. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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Comparison of two urinary antigen tests for establishment of pneumococcal etiology of adult community-acquired pneumonia
- 2004
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 42:8, s. 3620-3625
-
Tidskriftsartikel (refereegranskat)abstract
- The Binax NOW immunochromatographic test (ICT) detecting the pneumococcal C polysaccharide and a serotype-specific latex agglutination (LA) test detecting 23 pneumococcal capsular antigens were evaluated for establishing pneumococcal etiology in community-acquired pneumonia (CAP) by use of nonconcentrated urine. ICT was considered to be strongly positive for result lines at least as intense as the control line and weakly positive for less intense result lines. When 215 adult CAP patients were tested, strong ICT, weak ICT, and LA positivity were found in 28, 24, and 16 patients, respectively; of these patients, 13 (46%), 6 (25%), and 13 (81%), respectively, had pneumococcal bacteremia and 27 (96%), 17 (71%), and 15 (94%), respectively, had Streptococcus pneumoniae isolated from blood, sputum, and/or nasopharynx. Among 108 controls tested, 2 (1.9%) were weakly ICT positive. When weak positivity was considered negative, the sensitivity of ICT decreased from 79% (19 of 24) to 54% (13 of 24), while the specificity increased from 83% (158 of 191) to 92% (176 of 191); no controls were false positive. The sensitivity and specificity of LA were 54% (13 of 24) and 98% (188 of 191), respectively. Eight of nine LA serotypes corresponded to culture serotypes. In conclusion, using nonconcentrated urine and dividing ICT-positive results into strongly and weakly positive results is a suitable way of performing ICT. While weak ICT positivity should be interpreted with caution, strong ICT positivity and LA positivity should be considered supportive of pneumococcal etiology in adult CAP. As such, these assays might have implications for antibiotic use in CAP. LA has promising potential for pneumococcal serotyping, although further evaluation is required.
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| 40. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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Design of a multiplex PCR for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae and Chlamydophila pneumoniae to be used on sputum samples
- 2005
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 113:2, s. 99-111
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Tidskriftsartikel (refereegranskat)abstract
- A multiplex PCR (mPCR) was developed for simultaneous detection of specific genes for Streptococcus pneumoniae (lytA), Mycoplasma pneumoniae (P1), Chlamydophila pneumoniae (ompA), and Haemophilus influenzae (16S rRNA, with verification PCR for P6). When the protocol was tested on 257 bacterial strains belonging to 37 different species, no false negatives and only one false positive were noted. One Streptococcus mitis out of thirty was positive for lytA. In a pilot application study of 81 sputum samples from different patients with suspected lower respiratory tract infection (LRTI), mPCR identified S. pneumoniae in 25 samples, H. influenzae in 29, M. pneumoniae in 3, and C. pneumoniae in 1. All samples culture positive for S. pneumoniae (n=15) and H. influenzae (n=15) were mPCR positive for the same bacteria. In a pilot control study with nasopharyngeal swabs and aspirates from 10 healthy adults, both culture and mPCR were negative. No PCR inhibition was found in any of the mPCR-negative sputum or nasopharyngeal samples. Whether all samples identified as positive by mPCR are truly positive in an aetiological perspective regarding LRTI remains to be evaluated in a well-defined patient material. In conclusion, the mPCR appears to be a promising tool in the aetiological diagnostics of LRTI.
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| 41. |
- Strålin, Kristoffer, et al.
(författare)
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Design of a national patient-centred clinical pathway for sepsis in Sweden
- 2023
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Ingår i: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 55:10, s. 716-724
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The World Health Organization has adopted a resolution on sepsis and urged member states to develop national processes to improve sepsis care. In Sweden, sepsis was selected as one of the ten first diagnoses to be addressed, when the Swedish government in 2019 allocated funds for patient-centred clinical pathways in healthcare. A national multidisciplinary working group, including a patient representative, was appointed to develop the patient-centred clinical pathway for sepsis.METHODS: The working group mapped challenges and needs surrounding sepsis care and included a survey sent to all emergency departments (ED) in Sweden, and then designed a patient-centred clinical pathway for sepsis.RESULTS: The working group decided to focus on the following four areas: (1) sepsis alert for early detection and management optimisation for the most severely ill sepsis patients in the ED; (2) accurate sepsis diagnosis coding; (3) structured information to patients at discharge after sepsis care and (4) structured telephone follow-up after sepsis care. A health-economic analysis indicated that the implementation of the clinical pathway for sepsis will most likely not drive costs. An important aspect of the clinical pathway is implementing continuous monitoring of performance and process indicators. A national working group is currently building up such a system for monitoring, focusing on extraction of this information from the electronic health records systems.CONCLUSION: A national patient-centred clinical pathway for sepsis has been developed and is currently being implemented in Swedish healthcare. We believe that the clinical pathway and the accompanying monitoring will provide a more efficient and equal sepsis care and improved possibilities to monitor and further develop sepsis care in Sweden.
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| 42. |
- Strålin, Kristoffer, 1969-
(författare)
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Diagnostic methods for bacterial etiology in adult community-acquired pneumonia
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The etiologic agent is often unidentified in patients with community-acquired pneumonia (CAP). Development of new diagnostic methods has been encouraged. We aimed to develop a multiplex PCR (mPCR) assay for common bacterial pathogens and evaluate the diagnostic usefulness of this assay and of respiratory culture in CAP.An mPCR was constructed for simultaneous identification of Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. Applied to 257 bacterial strains, the analytic sensitivity was 100% and the analytic specificity 99%.In order to create appropriate reference standards, an indirect immunofluorescence test for H. influenzae was developed and two rapid urinary antigen tests for S. pneumoniae were evaluated. The indirect immunofluorescence test measured antibodies in paired sera against a H. influenzae strain isolated from the patient. A significant antibody rise was noted in 5/6 patients with lower respiratory tract infection (LRTI) and in 0/2 controls. The Binax NOW test and a serotype-specific latex agglutination test for 23 pneumococcal serotypes applied to urine samples, were positive in 24% and 7.4%, respectively, of 215 CAP patients tested. The Binax NOW test was false positive in 2/108 adult controls.In a prospective study, 235 adult CAP patients and 113 controls were enroled. S. pneumoniae, H. influenzae, M. pneumoniae, and C. pneumoniae were considered definite etiologic agents in 17%, 11%, 5.5%, and 1.3% of the patients, respectively. When applied to sputum, nasopharyngeal aspirate (NpA), and/or nasopharyngeal swab (NpS), culture identified S. pneumoniae in 34% and H. influenzae in 23%, while mPCR identified S. pneumoniae in 48%, H. influenzae in 28%, M. pneumoniae in 12%, and C. pneumoniae in 1.3%. NpA and sputum yielded similar sensitivities and specificities and were generally more sensitive than NpS. In samples collected during antibiotic treatment, S. pneumoniae was identified by culture in 4.3% and by mPCR in 14% (P=0.004). Among the controls, NpS and/or NpA identified S. pneumoniae in 4.4% with culture and 8.0% with mPCR, H. influenzae in 2.7% with culture and 4.4% with mPCR, and M. pneumoniae in 0.88% with mPCR.mPCR was also tested on bronchoalveolar lavage (BAL) samples from 156 adult patients with LRTI and 36 controls. BAL mPCR showed sensitivities of 86% for S. pneumoniae, 88% for H. influenzae, and 100% for M. pneumoniae, and specificities of 81% for S. pneumoniae, 64% for H. influenzae, 100% for M. pneumoniae, and 99% for C. pneumoniae. Among the controls, BAL mPCR identified S. pneumoniae in 11% and H. influenzae in 39%.In conclusion, an mPCR for detection off our bacteria was developed. Both culture and mPCR applied to sputum, NpA, and NpS were useful for detection of etiologic agents in CAP patients. mPCR appears particularly useful in patients treated with antibiotics. It can also be useful in BAL samples. The urinary antigen tests can reliably establish pneumococcal pneumonia.
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| 43. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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Etiologic diagnosis of adult bacterial pneumonia by culture and PCR applied to respiratory tract samples
- 2006
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 44:2, s. 643-645
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Tidskriftsartikel (refereegranskat)abstract
- Respiratory culture and multiplex PCR for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and Chlamydophila pneumoniae were applied to sputum, nasopharyngeal swabs, and nasopharyngeal aspirates from 235 adult patients with community-acquired pneumonia and 113 controls. Both culture and multiplex PCR performed well with the different samples and appear to be useful as diagnostic tools.
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| 44. |
- Strålin, Kristoffer, 1969-, et al.
(författare)
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Evaluation of a multiplex PCR for bacterial pathogens applied to bronchoalveolar lavage.
- 2006
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 28, s. 568-575
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Tidskriftsartikel (refereegranskat)abstract
- The present study assessed the diagnostic usefulness of a multiplex PCR (mPCR) for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae and Chlamydophila pneumoniae applied to bronchoalveolar lavage (BAL). Fibreoptic bronchoscopy was performed on 156 hospitalised adult patients with lower respiratory tract infection (LRTI) and 36 controls. BAL fluid was analysed with bacterial culture and mPCR. By conventional diagnostic methods, S. pneumoniae, H. influenzae, M. pneumoniae and C. pneumoniae were aetiological agents in 14, 21, 3.2 and 0% of the LRTI patients, respectively. These pathogens were identified by BAL mPCR in 28, 47, 3.2 and 0.6% of cases, respectively, yielding sensitivities of 86% for S. pneumoniae, 88% for H. influenzae, 100% for M. pneumoniae and 0% for C. pneumoniae, and specificities of 81, 64, 100 and 99% for S. pneumoniae, H. influenzae, M. pneumoniae and C. pneumoniae, respectively. Of the 103 patients who had taken antibiotics prior to bronchoscopy, S. pneumoniae was identified by culture in 2.9% and by mPCR in 31%. Among the controls, mPCR identified S. pneumoniae in 11% and H. influenzae in 39%. In lower respiratory tract infection patients, bronchoalveolar lavage multiplex PCR can be useful for identification of Streptococcus pneumoniae, Mycoplasma pneumoniae and Chlamydophila pneumoniae. The method appears to be particularly useful in patients treated with antibiotics.
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| 46. |
- Strålin, Kristoffer, et al.
(författare)
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Mortality in hospitalized COVID-19 patients was associated with the COVID-19 admission rate during the first year of the pandemic in Sweden
- 2022
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Ingår i: Infectious Diseases. - : Taylor & Francis Ltd. - 2374-4235 .- 2374-4243. ; 54:2, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Studies from the first pandemic wave found associations between COVID-19 hospital load and mortality. Here, we aimed to study if mortality of hospitalized COVID-19 patients was associated with the COVID-19 admission rate during a full year of the pandemic in Sweden. Method Observational review of all patients admitted to hospital with COVID-19 in Sweden between March 2020 and February 2021 (n = 42,017). Primary outcome was 60-day all-cause mortality related to number of COVID-19 hospital admissions per month/100,000 inhabitants. Poisson regression was used to estimate the relative risk for death by month of admission, adjusting for pre-existing factors. Results The overall mortality was 17.4%. Excluding March 2020, mortality was clearly correlated to the number of COVID-19 admissions per month (coefficient of correlation rho=.96; p<.0001). After adjustment for pre-existing factors, the correlation remained significant (rho=.75, p=.02). Patients admitted in December (high admission rate and high mortality) had more comorbidities and longer hospital stays, and patients treated in intensive care units (ICU) had longer pre-ICU hospital stays and worse respiratory status on ICU admission than those admitted in July to September (low admission rate and low mortality). Conclusion Mortality in hospitalized COVID-19 patients was clearly associated with the COVID-19 admission rate. Admission of healthier patients between pandemic waves and delayed ICU care during wave peaks could contribute to this pattern. The study supports measures to flatten-the-curve to reduce the number of COVID-19 patients admitted to hospital.
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| 47. |
- Strålin, Kristoffer, et al.
(författare)
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Mortality trends among hospitalised COVID-19 patients in Sweden : A nationwide observational cohort study
- 2021
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Ingår i: The Lancet Regional Health. - : Elsevier. - 2666-7762. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Background: It is important to know if mortality among hospitalised COVID-19 patients has changed as the pandemic has progressed. The aim of this study was to describe the dynamics over time of mortality among patients hospitalised for COVID-19 in Sweden, using nationwide data compiled by the Swedish National Board of Health and Welfare. Methods: Observational cohort study where all patients hospitalised in Sweden between March 1 and September 30, 2020, with SARS-CoV-2 RNA positivity 14 days before to 5 days after admission and a discharge code for COVID-19 were included. Outcome was 60-day all-cause mortality. Patients were categorised according to month of hospital admission. Poisson regression was used to estimate the relative risk of death by month of admission, adjusting for, age, sex, comorbidities, care dependency, country of birth, healthcare region, and Simplified Acute Physiology, version 3 (patients in intensive care units; ICU). Findings: A total of 17,140 patients were included, of which 2943 died within 60 days of admission. The overall 60-day mortality was thus 17.2% (95% CI, 16.6%-17.7%), and it decreased from 24.7% (95% CI, 23.0%-26.5%) in March to 10.4% (95% CI, 8.9%-12.1%) post-wave (July-September). Adjusted relative risk (RR) of death was 0.46 (95% CI, 0.39-0.54) post-wave, using March as reference. Corresponding RR for patients not admitted to ICU and those admitted to ICU were 0.49 (95% CI, 0.42-0.59) and 0.49 (95% CI, 0.33-0.72), respectively. The proportion of patients admitted to ICU decreased from 19.4% (95% CI, 17.9%-21.1%) in the March cohort to 8.9% (95% CI, 7.5%-10.6%) post-wave. Interpretation: There was a gradual decline in mortality during the spring of 2020 in Swedish hospitalised COVID-19 patients, independent of baseline patient characteristics. Future research is needed to explain the reasons for this decline. The changing COVID-19 mortality should be taken into account when management and results of studies from the first pandemic wave are evaluated. (C) 2021 The Authors. Published by Elsevier Ltd.
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| 48. |
- Strålin, Kristoffer, et al.
(författare)
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Multiplex PCR fir bacteruak etiology using branchoalveolar lavage in adults with lower respiratory tract infection
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Study objective: To study the usefulness of a diagnostic multiplex PCR (mPCR) for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and Chlamydophila pneumoniae applied to bronchoalveolar lavage (BAL) in lower respiratmy tract infection (LRTI).Design: Prospective diagnostic study.Setting: Silkeborg County Hospital, Silkeborg, Denmark.Patients and participants: Hospitalized adult LRTI patients (n=I56) and adult controls investigated on suspicion of malignancy (n=36).Interventions: After fiberoptic bronchoscopy (FOB) BAL fluid was analysed with bacterial culture and mPCR. S. pneumoniae and H. influenzae etiologies were established by cultures from blood, BAL and sputum, and urinary antigen test for S. pneumoniae. M. pneumoniae etiology was established by singleplex PCR on BAL and throat swab, and C. pneumoniae etiology by singleplex PCR and culture on BAL and throat swab.Measurements and Results: S. pneumoniae, H. influenzae, M. pneumoniae, and C. pneumoniae were etiologies in 14%, 21%, 3.2%, and 0, of the LRTI patients, respectively. These pathogens were identified by BAL mPCR in 28%, 47%, 3.2%, and 0.6%, respectively. The sensitivities of BAL mPCR were 0.86 for S. pneumoniae, 0.88 for H. influenzae, 1.0 for M. pneumoniae, and 0/0 for C. pneumoniae. The specificities were 0.81 for S. pneumoniae, 0.64 for H. influenzae, 1.0 for M. pneumoniae, and 0.99 for C. pneumoniae. In 103 patients with antibiotics taken prior to FOB, BAL culture and BAL mPCR identified S. pneumoniae in 2.9% and 31%, respectively, and H. influenzae in 20% and 50%, respectively. Among the controls, BAL culture and mPCR identified S. pneumoniae in 8.3% and 11%, respectively, and H. influenzae in 11% and 39%, respectively. No M. pneumoniae or C. pneumoniae was identified among the controls.Conclusions: In LRTI patients, BAL mPCR can be useful for identification of S. pneumoniae, M. pneumoniae, and C. pneumoniae. The method appears particularly useful in patients treated with antibiotics.
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| 49. |
- Strålin, Kristoffer, et al.
(författare)
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Performance of PCR/electrospray ionization-mass spectrometry on whole blood for detection of bloodstream microorganisms in patients with suspected sepsis
- 2020
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 58:9, s. e01860-19
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Tidskriftsartikel (refereegranskat)abstract
- Blood culture (BC) often fails to detect bloodstream microorganisms in sepsis. However, molecular diagnostics hold great potential. The molecular method PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS) can detect DNA from hundreds of different microorganisms in whole blood. The aim of the present study was to evaluate the performance of this method in a multicenter study including 16 teaching hospitals in the USA (n=13) and Europe (n=3). First, on 2,754 contrived whole blood samples, with or without spiked microorganisms, PCR/ESI-MS produced 99.1% true positive and 97.2% true negative results. Secondly, among 1,460 patients with suspected sepsis (sepsis-2 definition), BC and PCR/ESI-MS on whole blood were positive in 14.6% and 25.6% of cases, respectively, with the following result combinations: BC+/PCR/ESI-MS-, 4.3%; BC+/PCR/ESI-MS+, 10.3%; BC-/PCR/ESI-MS+, 15.3%; and BC-/PCR/ESI-MS-, 70.1%. Compared with BC, PCR/ESI-MS showed the following sensitivities (coagulase-negative staphylococci not included): Gram-positive bacteria, 58%; Gram-negative bacteria, 78%; and Candida species, 83%. The specificities were > 94% for all individual species. Patients treated with prior antimicrobial medications (n=603) had significantly increased PCR/ESI-MS positivity rates compared with patients without prior antimicrobial treatment, 31% vs 22% (p<0.0001), with pronounced differences for Gram-negative bacteria and Candida species. In conclusion, PCR/ESI-MS showed excellent performance on contrived samples. On clinical samples, it showed high specificities, moderately high sensitivities for Gram-negative bacteria and Candida species, and elevated positivity rates during antimicrobial treatment. These promising results encourage further development of molecular diagnostics on whole blood for detection of bloodstream microorganisms in sepsis.
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| 50. |
- Strålin, Kristoffer, et al.
(författare)
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Sepsislarm, korrekt diagnos och telefonuppföljning i fokus : [Person-centered clinical pathway for sepsis approved for implementation in Sweden]
- 2021
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Ingår i: Läkartidningen. - : Läkartidningen Förlag AB. - 0023-7205 .- 1652-7518. ; 118, s. 48-49
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Tidskriftsartikel (refereegranskat)abstract
- A national multidisciplinary working group was assigned by the Swedish Association of Local Authorities and Regions to create a person-centered clinical pathway for sepsis in adults. This clinical pathway has been approved for implementation in the Swedish healthcare system. It focuses on three interventions: a sepsis alert for patients with instable vital signs and suspected sepsis in the emergency department, the correct discharge coding of sepsis according to ICD-10 codes, and a structured patient follow-up after hospital discharge. Quality indicators will be registered and monitored electronically. A health-economic analysis indicates that the clinical pathway will not drive additional costs for the healthcare system.
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