| 1. |
- Chen, Q., et al.
(författare)
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Fast determination of antibiotics in whole blood
- 2013
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 19:9, s. 869-874
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for analytical methods capable of monitoring blood antibiotic levels in real time. Here we present a method for quantifying antibiotic levels in whole blood that does not require any sample pretreatment. The tests employ the enzyme penicillinase to assay for penicillin G, penicillin V and ampicillin using a flow-injected biosensor, the Enzyme Thermistor. Optimal flow rates, sample volumes and pH were determined to be 0.5mL/min, 100L and 7.0, respectively. Analysis of the antibiotics diluted in buffer gave a linear range of 0.17-5.0mM. Calibration curves prepared using blood spiked with the antibiotics gave a linear range of 0.17-2.0mM. Linear regression values for all of the calibration curves were 0.998 or higher. Assay cycle time was 5min. The relative standard deviation value for 100 determinations of a mock blood sample spiked with penicillin G was 6.71%. Despite the elimination of sample pretreatment, no detectable clogging or signal drift was observed. The assay provides a fast, simple, reliable analytical method for determining antibiotic concentrations in blood without the need for any sample pretreatment. This is an important first step towards developing a device capable of real-time monitoring of antibiotic levels in whole blood. The technology has the potential to significantly improve the outcomes of patients undergoing critical care.
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| 2. |
- Inghammar, Malin, et al.
(författare)
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Invasive pneumococcal disease in patients with an underlying pulmonary disorder.
- 2013
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 19:12, s. 1148-1154
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Tidskriftsartikel (refereegranskat)abstract
- Chronic pulmonary disease is a recognized risk factor for invasive pneumococcal disease (IPD). However, previous studies have often not been large enough to allow detailed analyses of less prevalent pulmonary diseases, and findings regarding case fatality have been inconsistent. We examined the associations between an underlying pulmonary disease and IPD, and the impact of these diseases on the case fatality rate. Patients with IPD ≥18 years of age, between 1990 and 2008, were identified in microbiological databases. The associations between IPD and the pulmonary diseases were assessed using conditional logistic regression, comparing IPD cases to ten control subjects per case, randomly selected from the general population (matched for gender, year of birth and county of residence). Adjustments were made for other co-morbidities, level of education and socio-economic status, 4085 cases of IPD and 40 353 controls were identified. A more than four-fold increased risk of IPD was seen in chronic obstructive pulmonary disease, a doubled risk in asthma and a five-fold increased risk in subjects with pulmonary fibrosis. In univariate analysis, sarcoidosis and bronchiectasis were associated with a two-fold to seven-fold increase in the risk of IPD, but there was no statistical support for the associations when adjustments for confounders were made. No increased risk was seen in subjects with a history of pneumoconiosis or allergic alveolitis. The mortality following IPD was not increased in patients with chronic obstructive pulmonary disease, asthma, pulmonary fibrosis or bronchiectasis. Several chronic pulmonary diseases increase the risk of IPD but mortality following IPD seems not to be affected.
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| 3. |
- Kabayiza, Jean-Claude, et al.
(författare)
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Diarrhoeagenic microbes by real-time PCR in Rwandan children under 5 years of age with acute gastroenteritis.
- 2014
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X. ; 20:12, s. O1128-35
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Tidskriftsartikel (refereegranskat)abstract
- Acute gastroenteritis is a main cause of disease and death among children in low-income countries. The causality rates and pathogenic characteristics of putative aetiological agents remain insufficiently known. We used real-time PCR targeting 16 diarrhoeagenic agents to analyse stool samples from children ≤5.0 years old with acute diarrhoea in Rwanda. Among the 880 children (median age 14.2 months; 41% female) at least one pathogen was detected in 92% and two or more agents in 63% of cases. Rotavirus was detected in 36.9%, adenovirus in 39.7%, enterotoxigenic Escherichia coli (ETEC) with genes for labile (eltB) or stable (estA) toxin in 31.3% and 19.0%, E. coli with eae or bfpA genes in 25.2% and 14.2%, Shigella in 17.5% and Cryptosporidium in 7.8%. Rotavirus and ETEC-estA were associated with more severe dehydration than diarrhoea due to other causes. Shigella was associated with bloody stools and higher CRP. Microbial loads (Ct values) of rotavirus, ETEC-estA and Shigella were associated with severity of symptoms. Rotavirus, ETEC-estA and E. coli with bfpA were associated with younger age, Shigella with older age. Antibiotic treatment was given to 42% and was associated with dehydration, fever and CRP, but not with pathogen. We conclude that rotavirus and ETEC-estA were the most important causes of diarrhoea with dehydration, that Shigella caused bloody diarrhoea but less severe dehydration, that microbial loads of rotavirus, ETEC-estA and Shigella were associated with severity of symptoms, and that antibiotic use was frequent and in poor agreement with microbiological findings.
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| 4. |
- Kaukonen, K. -M., et al.
(författare)
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Heparin-binding protein (HBP) in critically ill patients with influenza A (H1N1) infection
- 2013
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 19:12, s. 1122-1128
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Tidskriftsartikel (refereegranskat)abstract
- Heparin-binding protein (HBP) is an inducer of vascular endothelial leakage in severe infections. Fluid accumulation into alveoli is a general finding in acute respiratory distress syndrome (ARDS). Severe acute respiratory failure with ARDS is a complication of influenza A(H1N1) infection. Accordingly, we studied the HBP levels in critically ill patients with infection of influenza A(H1N1).Critically ill patients in four intensive care units (ICUs) with polymerase chain reaction (PCR) confirmed infection of influenza A(H1N1) were prospectively evaluated. We collected clinical data and blood samples at ICU admission and on day 2. Twenty-nine patients participated in the study. Compared with normal plasma levels, the HBP concentrations were highly elevated at baseline and at day 2: 98ng/mL (62-183ng/mL) and 93ng/mL (62-271ng/mL) (p 0.876), respectively. HBP concentrations were correlated with the lowest ratio of partial pressure of oxygen in arterial blood to fraction of inspired oxygen (PF ratio) during the ICU stay (rho=-0.321, p<0.05). In patients with and without invasive mechanical ventilation, the baseline HBP levels were 152ng/mL (72-237ng/mL) and 83ng/mL (58-108ng/mL) (p 0.088), respectively. The respective values at day 2 were 223ng/mL (89-415ng/mL) and 81ng/mL (55-97ng/mL) (p<0.05). The patients with septic shock/severe sepsis (compared with those without) did not have statistically significant differences in HBP concentrations at baseline or day 2. HBP concentrations are markedly elevated in all critically ill patients with influenza A(H1N1) infection. The increase in HBP concentrations seems to be associated with more pronounced respiratory dysfunction.
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| 5. |
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| 6. |
- Arendrup, M. C., et al.
(författare)
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Detection of candidaemia in patients with and without underlying haematological disease
- 2010
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 16:7, s. 855-862
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Tidskriftsartikel (refereegranskat)abstract
- P>Diagnosing candidaemia remains difficult despite the development of new diagnostics. We report a direct comparison of three different blood-culture systems and four indirect tests. One hundred and fourteen episodes either with haematological disease and fever despite antibacterials, or with documented invasive candidiasis, were enrolled prospectively. Clinical, para-clinical information and surveillance cultures were obtained. Blood culture was performed using conventional blood-culture bottles, mycosis bottles, and the Isolator 10 lysis centrifugation system. Serum D-arabinitol/L-arabinitol (DA/LA) ratios were determined by gas chromatography mass spectrometry. Antigen, mannan-antigen (Ag) and anti-mannan antibody (Ab) were detected by CandTec, Platelia Candida Ag ELISA and Candida AB/AC/AK kits, respectively. Episodes were classified as proven (n = 24), probable (n = 14), possible (n = 52) or unlikely (n = 24) invasive candidiasis. Candidaemia involved C. albicans (17), C. albicans + C. glabrata (3), C. tropicalis (1) and yeast (1). Mycosis bottles yielded two additional positives and the conventional blood culture yielded one positive not identified by other blood-culture methods. Considering proven and unlikely episodes, respectively, sensitivity and specificity were as follows: mannan-Ag and/or anti-mannan Ab: 83.3%, 78.3%; DA/LA ratio: 41.7%, 86.4%; and CandTec Candida Ag: 66.6%, 70.8%. Lowering the cut-off values to mannan-Ag 0.10 ng/mL and anti-mannan Ab 4 AU/mL, the values were: 100%, 73.9%. Applying the DA/LA ratio to only patients with haematological neutropenia the values were: 75%, 90.5%. Fungal blood culture allowed slightly improved detection of candidaemia. The best indirect test performance was obtained from combined mannan-Ag and anti-mannan Ab detection, especially with lower cut-offs. DA/LA ratio appears to be useful in the context of haematological neutropenia.
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| 7. |
- Holmberg, Anna, et al.
(författare)
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Biofilm formation by Propionibacterium acnes is a characteristic of invasive isolates
- 2009
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 15:8, s. 787-795
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Tidskriftsartikel (refereegranskat)abstract
- Propionibacterium acnes is a common and probably underestimated cause of delayed joint prosthesis infection. Bacterial biofilm formation is central in the pathogenesis of infections related to foreign material, and P. acnes has been shown to form biofilm both in vitro and in vivo. Here, biofilm formation by 93 P. acnes isolates, either from invasive infections (n = 45) or from the skin of healthy people (n = 48), was analysed. The majority of isolates from deep infections produced biofilm in a microtitre model of biofilm formation, whereas the skin isolates were poor biofilm producers (p <0.001 for a difference). This indicates a role for biofilm formation in P. acnes virulence. The type distribution, as determined by sequencing of recA, was similar among isolates isolated from skin and from deep infections, demonstrating that P. acnes isolates with different genetic backgrounds have pathogenic potential. The biofilm formed on plastic and on bone cement was analysed by scanning electron microscopy (EM) and by transmission EM. The biofilm was seen as a 10-mum-thick layer covering the bacteria and was composed of filamentous as well as more amorphous structures. Interestingly, the presence of human plasma in solution or at the plastic surface inhibits biofilm formation, which could explain why P. acnes primarily infect plasma-poor environments of, for example, joint prostheses and cerebrospinal shunts. This work underlines the importance of biofilm formation in P. acnes pathogenesis, and shows that biofilm formation should be considered in the diagnosis and treatment of invasive P. acnes infections.
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| 8. |
- Kahlmeter, G, et al.
(författare)
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European Committee on Antimicrobial Susceptibility Testing (EUCAST) Technical Notes on antimicrobial susceptibility testing
- 2006
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 12:6, s. 501-503
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The main objectives of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are to harmonise breakpoints for antimicrobial agents in Europe, and to act as the breakpoint committee for the European Medicines Agency (EMEA) during the registration of new antimicrobial agents. Detailed EUCAST procedures for harmonising and setting breakpoints for antimicrobial agents are available on the EUCAST website. Beginning with the current issue, a series of EUCAST Technical Notes will be published in CMI, based on the rationale documents produced by EUCAST for each of the antimicrobial agents studied, with the aim of highlighting important background information underlying decisions on breakpoints made by EUCAST.
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| 9. |
- Knudsen, TB, et al.
(författare)
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Predictive value of soluble haemoglobin scavenger receptor CD163 serum levels for survival in verified tuberculosis patients
- 2005
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 11:9, s. 730-735
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Tidskriftsartikel (refereegranskat)abstract
- Pre-treatment serum levels of sCD163 were measured in a cohort of 236 suspected tuberculosis (TB) cases from Guinea-Bissau, with a median follow-up period of 3.3 years (range 0-6.4 years). In 113 cases, the diagnosis of TB was verified by positive sputum microscopy and/or culture. Among the verified TB cases, a decreased survival rate was found in 27 patients with sCD163 levels above the upper reference limit (3.95 mu g/mL). The difference in survival was significant during TB treatment (log rank, p < 0.02) and after long-term follow-up (log rank, p < 0.001). The decrease in survival rate during TB treatment remained significant in a multivariate Cox model controlling for human immunodeficiency virus (HIV) status, age and gender, with a mortality increase of 1.19 (95% CI, 1.04-1.36) per mu g of sCD163, and a hazard ratio (HR) for sCD163 levels above the upper reference limit of 4.18 (95% CI, 1.06-16.4). The difference was not significant after excluding patients with concomitant HIV-1 and HIV-2 infection in Kaplan-Meier analyses (log rank, p 0.11). In contrast, the difference in survival remained significant in Kaplan-Meier analyses after long-term follow-up, even after excluding patients with concomitant HIV-1 and HIV-2 infection (log rank, p 0.002). In the Cox model, the mortality increase per mu g of sCD163 was 1.27 (95% CI, 1.14-1.40), with an HR for elevated sCD163 levels of 2.85 (95% CI, 1.44-5.63). The HRs for concomitant HIV-1 and HIV-2 infection were 6.92 (95% CI, 3.28-14.58) and 2.48 (95% CI, 1.09-5.67), respectively. Thus, sCD163 levels appeared to be an independent predictor of survival in verified TB patients.
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| 10. |
- Kronvall, G., et al.
(författare)
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A new method for normalized interpretation of antimicrobial resistance from disk test results for comparative purposes.
- 2003
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 9:2, s. 120-132
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Tidskriftsartikel (refereegranskat)abstract
- Objective To evaluate a calibration method for disk diffusion antibiotic susceptibility tests, using zone diameter values generated in the individual laboratory as the internal calibrator for combinations of antibiotic and bacterial species. Methods The high-zone side of zone histogram distributions was first analyzed by moving averages to determine the peak position of the susceptible population. The accumulated percentages of isolates for the high zone diameter values were calculated and converted into probit values. The normal distribution of the ideal population of susceptible strains was then determined by using the least-squares method for probit values against zone diameters, and the ideal population was thereby defined, including mean and standard deviation. Zone diameter values were obtained from laboratories at the Karolinska Hospital (KS) and Växjö Hospital (VX), and from two laboratories (LabA, LabB) in Argentina. The method relies on well standardized disk tests, but is independent of differences in MIC limits and zone breakpoints, and does not require the use of reference strains. Resistance was tentatively set at below 3 SD from the calculated, ideal mean zone diameter of the susceptible population. Results The method, called normalized interpretation of antimicrobial resistance, was tested on results from the KS and VX clinical microbiology laboratories, using the disk diffusion method for antimicrobial susceptibility tests, and for two bacterial species, Staphylococcus aureus and Escherichia coli. In total, 114 217 test results were included for the clinical isolates, and 3582 test results for control strains. The methodology at KS and VX followed the standard of the Swedish Reference Group for Antibiotics (SRGA). Zone diameter histograms for control strains were first analyzed to validate the procedure, and a comparison of actual means with the calculated means showed a correlation coefficient of r = 0.998. Results for clinical isolates at the two laboratories showed an excellent agreement for 54 of 57 combinations of antibiotic and bacterial species between normalized interpretations and the interpretations given by the laboratories. There were difficulties with E. coli and mecillinam, and S. aureus and tetracycline and rifampicin. The method was also tested on results from two laboratories using the NCCLS standard, and preliminary results showed very good agreement with quality-controlled laboratory interpretations. Conclusions The normalized resistance interpretation offers a new approach to comparative surveillance studies whereby the inhibition zone diameter results from disk tests in clinical laboratories can be used for calibration of the test.
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