Journal of clinical microbiology
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J. Clin. Microbiol. · Jun 2014
Comparative StudyPerformance of galactomannan, beta-d-glucan, Aspergillus lateral-flow device, conventional culture, and PCR tests with bronchoalveolar lavage fluid for diagnosis of invasive pulmonary aspergillosis.
Galactomannan detection in bronchoalveolar lavage (BAL) fluid samples (GM test) is currently considered the gold standard test for diagnosing invasive pulmonary aspergillosis (IPA). The limitations, however, are the various turnaround times and availability of testing. We compared the performance of GM testing with that of conventional culture, an Aspergillus lateral-flow-device (LFD) test, a beta-d-glucan (BDG) test, and an Aspergillus PCR assay by using BAL fluid samples from immunocompromised patients. ⋯ The performance of conventional culture was limited by low sensitivity, while that of the BDG test was limited by low specificity. We evaluated established and novel diagnostic methods for IPA and found that the Aspergillus PCR, LFD, and GM tests were the most useful methods for diagnosing the disease by using BAL fluid samples. In particular, the combination of the GM test and PCR or, if PCR is not available, the LFD test, allows for sensitive and specific diagnosis of IPA.
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J. Clin. Microbiol. · Jun 2014
Multiplex real-time PCR assay for rapid detection of methicillin-resistant staphylococci directly from positive blood cultures.
Methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent cause of bloodstream infections (BSIs) and is recognized as a major nosocomial pathogen. This study aimed to evaluate a newly designed multiplex real-time PCR assay capable of the simultaneous detection of mecA, S. aureus, and coagulase-negative staphylococci (CoNS) in blood culture specimens. The Real-MRSA and Real-MRCoNS multiplex real-time PCR assays (M&D, Republic of Korea) use the TaqMan probes 16S rRNA for Staphylococcus spp., the nuc gene for S. aureus, and the mecA gene for methicillin resistance. ⋯ Of 350 positive bottle cultures, the sensitivities of the multiplex real-time PCR kit were 100% (166/166 cultures), 97.2% (35/36 cultures), and 99.2% (117/118 cultures) for the 16S rRNA, nuc, and mecA genes, respectively, and the specificities for all three targets were 100%. The Real-MRSA and Real-MRCoNS multiplex real-time PCR assays are very useful for the rapid accurate diagnosis of staphylococcal BSIs. In addition, the Real-MRSA and Real-MRCoNS multiplex real-time PCR assays could have an important impact on the choice of appropriate antimicrobial therapy, based on detection of the mecA gene.
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J. Clin. Microbiol. · Jun 2014
Antifungal drug susceptibility and phylogenetic diversity among Cryptococcus isolates from dogs and cats in North America.
Molecular types of the Cryptococcus neoformans/Cryptococcus gattii species complex that infect dogs and cats differ regionally and with host species. Antifungal drug susceptibility can vary with molecular type, but the susceptibility of Cryptococcus isolates from dogs and cats is largely unknown. Cryptococcus isolates from 15 dogs and 27 cats were typed using URA5 restriction fragment length polymorphism analysis (RFLP), PCR fingerprinting, and multilocus sequence typing (MLST). ⋯ For all drugs except itraconazole, C. gattii isolates exhibited a wider range of MICs than C. neoformans. MICs varied with Cryptococcus species and molecular type in dogs and cats, and MICs of VGIII isolates were most variable and may reflect phylogenetic diversity in this group. Because sequence types of dogs and cats reflect those infecting humans, these observations may also have implications for treatment of human cryptococcosis.
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J. Clin. Microbiol. · May 2014
Chronic Q fever in the Netherlands 5 years after the start of the Q fever epidemic: results from the Dutch chronic Q fever database.
Coxiella burnetii causes Q fever, a zoonosis, which has acute and chronic manifestations. From 2007 to 2010, the Netherlands experienced a large Q fever outbreak, which has offered a unique opportunity to analyze chronic Q fever cases. In an observational cohort study, baseline characteristics and clinical characteristics, as well as mortality, of patients with proven, probable, or possible chronic Q fever in the Netherlands, were analyzed. ⋯ An acute Q fever episode was recalled by 27.0% of the patients. The all-cause mortality rate was 19.1%, while the chronic Q fever-related mortality rate was 13.0%, with mortality rates of 9.3% among endocarditis patients and 18% among patients with a vascular focus of infection. Increasing age (P=0.004 and 0.010), proven chronic Q fever (P=0.020 and 0.002), vascular chronic Q fever (P=0.024 and 0.005), acute presentation with chronic Q fever (P=0.002 and P<0.001), and surgical treatment of chronic Q fever (P=0.025 and P<0.001) were significantly associated with all-cause mortality and chronic Q fever-related mortality, respectively.
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J. Clin. Microbiol. · Apr 2014
Rapid identification of bacteria and Candida pathogens in peritoneal dialysis effluent from patients with peritoneal dialysis-related peritonitis by use of multilocus PCR coupled with electrospray ionization mass spectrometry.
PCR coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was compared with culture for pathogen detection in peritoneal dialysis (PD)-related peritonitis. Of 21 samples of PD effluent, PCR/ESI-MS identified microorganisms in 18 (86%) samples, including Mycobacterium tuberculosis in 1 culture-negative sample. Of 15 double-positive samples, PCR/ESI-MS and culture reached levels of agreement of 100% (15/15) and 87.5% (7/8) at the genus and species levels, respectively. PCR/ESI-MS can be used for rapid pathogen detection in PD-related peritonitis.