| 1. |
- Isaksson, Jenny, et al.
(författare)
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Comparison of species identification of endocarditis associated viridans streptococci using rnpB genotyping and 2 MALDI-TOF systems
- 2015
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Ingår i: Diagnostic Microbiology and Infectious Disease. - : Elsevier BV. - 0732-8893 .- 1879-0070. ; 81:4, s. 240-245
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Tidskriftsartikel (refereegranskat)abstract
- Streptococcus spp. are important causes of infective endocarditis but challenging in species identification. This study compared identification based on sequence determination of the rnpB gene with 2 systems of matrix-assisted laser desorption ionization-time of flight mass spectrometry, MALDI Biotyper (Bruker) and VITEK MS IVD (bioMerieux). Blood culture isolates of viridans streptococci from 63 patients with infective endocarditis were tested. The 3 methods showed full agreement for all 36 isolates identified in the Anginosus, Bovis, and Mutans groups or identified as Streptococcus cristatus, Streptococcus gordonii, or Streptococcus sanguinis. None of the methods could reliably identify the 23 isolates to the species level when designated as Streptococcus mitis, Streptococcus oralis, or Streptococcus tigurinus. In 7 isolates classified to the Mitis group, the rnpB sequences deviated strikingly from all reference sequences, and additional analysis of sodA and groEL genes indicated the occurrence of yet unidentified Streptococcus spp. (C) 2015 Elsevier Inc. All rights reserved.
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| 2. |
- 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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| 3. |
- Lindblom, Anna, et al.
(författare)
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Interspecies plasmid transfer appears rare in sequential infections with extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae
- 2019
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Ingår i: Diagnostic Microbiology and Infectious Disease. - : Elsevier BV. - 0732-8893 .- 1879-0070. ; 93:4, s. 380-385
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Tidskriftsartikel (refereegranskat)abstract
- From a cohort of 1836 Swedish patients infected with ESBL-producing Enterobacteriaceae (EPE) during 2004-2014, 513 patients with recurrent EPE infection were identified. Only in 14 of the 513 patients was a change of species (ESBL-E. coli to ESBL-K. pneumoniae or vice versa) found between the index and subsequent infection. Eleven sequential urine isolates from 5 of the 14 patients were available for further analysis of possible transfer of ESBL-carrying plasmids. The plasmid content was studied using optical DNA mapping (ODM), PCR-based replicon typing, and ESBL gene sequencing. ODM allowed us to directly compare whole plasmids between isolates and found similar ESBL-carrying plasmids in 3 out of the 5 patients. The ODM results and the rarity in shift of species between ESBL-E. coli and ESBL-K. pneumoniae imply that in recurrent EPE infections interspecies plasmid transfer is uncommon. (C) 2018 Elsevier Inc. All rights reserved.
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| 4. |
- Lindström, Johan, 1984, et al.
(författare)
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CXCL13 in patients with facial palsy caused by varicella zoster virus and Borrelia burgdorferi: a comparative study.
- 2020
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier BV. - 1879-0070 .- 0732-8893. ; 98:1
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Tidskriftsartikel (refereegranskat)abstract
- High cerebrospinal fluid (CSF) concentrations of the chemokine CXCL13 have been associated with Lyme neuroborreliosis (LNB), and have recently been studied as a potential diagnostic marker. It has proven difficult to establish a reliable diagnostic cut-off, possibly in part due to heterogenicity of case-control groups. Our purpose was to investigate CSF CXCL13 concentrations in patients with similar clinical presentations, facial palsy. We retrospectively included patients with facial palsy associated with LNB (n=21), or varicella zoster virus (VZV) (n=26). Median CXCL13 concentrations were significantly higher in patients with LNB facial palsy compared to VZV facial palsy. Receiver-operating characteristic analyses yielded an optimal cut-off concentration at 34.5pg/mL (sensitivity 85.7%, specificity of 84.6%), lower than that in previous studies. Although the analysis has potential, it is still not adequately established that CXCL13 provides additional, clinically useful, diagnostic information over current recommendations.
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| 5. |
- 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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| 6. |
- Barisic, Ivan, et al.
(författare)
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Multiplex detection of antibiotic resistance genes using padlock probes
- 2013
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier BV. - 0732-8893 .- 1879-0070. ; 77:2, s. 118-125
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Tidskriftsartikel (refereegranskat)abstract
- The elucidation of resistance mechanisms is of central importance to providing and maintaining efficient medical treatment. However, molecular detection methods covering the complete set of resistance genes with a single test are still missing. Here, we present a novel 100-plex assay based on padlock probes in combination with a microarray that allows the simultaneous large-scale identification of highly diverse beta-lactamases. The specificity of the assay was performed using 70 clinical bacterial isolates, recovering 98% of the beta-lactamase nucleotide sequences present. Additionally, the sensitivity was evaluated with PCR products and genomic bacterial DNA, revealing a detection limit of 10(4) DNA copies per reaction when using PCR products as the template. Pre-amplification of genomic DNA in a 25-multiplex PCR further facilitated the detection of beta-lactamase genes in dilutions of 10(7) cells/mL. In summary, we present an efficient, highly specific, and highly sensitive multiplex detection method for any gene.
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| 7. |
- Dumke, Roger, et al.
(författare)
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Multi-center evaluation of one commercial and 12 in-house real-time PCR assays for detection of Mycoplasma pneumoniae
- 2017
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Ingår i: Diagnostic microbiology and infectious disease. - : ELSEVIER SCIENCE INC. - 0732-8893 .- 1879-0070. ; 88:2, s. 111-114
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Tidskriftsartikel (refereegranskat)abstract
- Detection of Mycoplasma pneumoniae by real-time PCR is not yet standardized across laboratories. We have implemented a standardization protocol to compare the performance of thirteen commercial and in-house approaches. Despite differences on threshold values of samples, all assays were able to detect at least 20 M. pneumoniae genomes per reaction.
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| 8. |
- Gullsby, Karolina, et al.
(författare)
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Comparison of three real-time PCR methods for detection of macrolide-resistant Mycoplasma genitalium in Sweden
- 2021
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Ingår i: Diagnostic microbiology and infectious disease. - : Elsevier BV. - 0732-8893 .- 1879-0070. ; 100:3
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Tidskriftsartikel (refereegranskat)abstract
- There is a worldwide increase in macrolide-resistant Mycoplasma genitalium strains, with severe impacts on treatment. The aim of this study was to compare three real-time PCR methods for the detection of macrolide resistance: an in-house PCR described by Touati et al., ResistancePlus® MG (SpeeDx), and S-DiaMGRes™ (Diagenode Diagnostics). One hundred M. genitalium-positive patient samples collected in Sweden and a quantitated M. genitalium DNA control were analyzed. Macrolide resistance was detected in 18, 15, and 16 of the samples with the respective methods. Sequencing of the 23S rRNA gene confirmed resistance in 16 (16%) of 100 samples in which it was detected with any of the three methods. ResistancePlus® MG and S-DiaMGRes™ falsely determined one sample as macrolide-sensitive, but this sample was determined as resistant when retested. The sensitivity of the methods was comparable, although there should be awareness of possible incorrect determination of macrolide resistance, especially of low-positive samples.
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| 9. |
- Holmberg, Anna, et al.
(författare)
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Mature biofilms of Enterococcus faecalis and Enterococcus faecium are highly resistant to antibiotics.
- 2016
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Ingår i: Diagnostic Microbiology and Infectious Disease. - : Elsevier BV. - 1879-0070 .- 0732-8893. ; 84:1, s. 19-21
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Tidskriftsartikel (refereegranskat)abstract
- Enterococcus faecalis and Enterococcus faecium are important nosocomial pathogens that form biofilms on implanted materials. We compare the antibiotic sensitivity of bacteria in new (established during 24hours) and mature (established during 120hours) enterococcal biofilms. Mature biofilms contained more bacteria and were much more tolerant to antibiotics, including rifampicin-containing combinations, as judged by determination of minimal biofilm eradication concentrations and by time-kill experiments of bacteria in biofilms formed on beads of bone cement.
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| 10. |
- Kjölvmark, Charlott, et al.
(författare)
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Distinguishing asymptomatic bacteriuria from urinary tract infection in the elderly - the use of urine levels of heparin-binding protein and interleukin-6
- 2016
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Ingår i: Diagnostic Microbiology and Infectious Disease. - : Elsevier BV. - 1879-0070 .- 0732-8893. ; 85:2, s. 243-248
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Tidskriftsartikel (refereegranskat)abstract
- Asymptomatic bacteriuria (ABU) is highly prevalent among elderly patients. It can be difficult to distinguish ABU from symptomatic urinary tract infection (UTI) in this population, which leads to unnecessary antibiotic treatment. Urinary heparin-binding protein (U-HBP) and urinary interleukin-6 (U-IL-6) have previously been studied as diagnostic markers for UTI. In this study, biomarkers were measured in the urine of 134 nursing home residents. The prevalence of ABU in this population, excluding patients with urinary catheter, was 32.8%. Levels of U-HBP and IL-6 were significantly lower among residents with ABU when compared to 49 patients with verified UTI. When previously defined cut-off limits were used, U-HBP had a high negative predictive value for UTI (93%), however, the specificity for differentiating patients with UTI and ABU was low. Discriminatory values were better for U-IL-6 with a sensitivity of 80% and specificity of 82% for the differentiation between the subgroup of pyelonephritis and ABU.
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