Journal of clinical microbiology
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J. Clin. Microbiol. · Nov 2012
Case ReportsBuruli ulcer disease in travelers and differentiation of Mycobacterium ulcerans strains from northern Australia.
Buruli ulcer (BU) is a necrotizing infection of skin and soft tissue caused by Mycobacterium ulcerans. In Australia, most cases of BU are linked to temperate, coastal Victoria and tropical, northern Queensland, and strains from these regions are distinguishable by variable-number tandem repeat (VNTR) typing. We present an epidemiological investigation of five patients found to have been infected during interstate travel and describe two nucleotide polymorphisms that differentiate M. ulcerans strains from northern Australia.
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J. Clin. Microbiol. · Oct 2012
Comparative StudyProspective evaluation of a matrix-assisted laser desorption ionization-time of flight mass spectrometry system in a hospital clinical microbiology laboratory for identification of bacteria and yeasts: a bench-by-bench study for assessing the impact on time to identification and cost-effectiveness.
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been found to be an accurate, rapid, and inexpensive method for the identification of bacteria and yeasts. Previous evaluations have compared the accuracy, time to identification, and costs of the MALDI-TOF MS method against standard identification systems or commercial panels. In this prospective study, we compared a protocol incorporating MALDI-TOF MS (MALDI protocol) with the current standard identification protocols (standard protocol) to determine the performance in actual practice using a specimen-based, bench-by-bench approach. ⋯ In our laboratory, we anticipate that the incorporation of the MALDI protocol can reduce reagent and labor costs of identification by $102,424 or 56.9% within 12 months. The model included the fixed annual costs of the MALDI-TOF MS, such as the cost of protein standards and instrument maintenance, and the annual prevalence of organisms encountered in our laboratory. This comprehensive cost analysis model can be generalized to other moderate- to high-volume laboratories.
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J. Clin. Microbiol. · Sep 2012
Recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.
This study investigated the clinical and microbiological characteristics of patients with recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex at a medical center. All ACB complex isolates associated with recurrent bacteremia were identified to the genomic species level using a 16S-23S rRNA gene intergenic spacer sequence-based method. Genotypes were determined by the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR and by pulsotypes generated by pulsed-field gel electrophoresis. ⋯ A. baumannii isolates had lower antimicrobial susceptibility rates than A. nosocomialis and A. pittii isolates. In conclusion, relapse of ACB complex bacteremia can develop in immunocompromised patients, especially those with central venous catheters. Molecular methods to identify the ACB complex to the genospecies level are essential for differentiating between reinfection and relapse of bacteremia caused by the ACB complex.
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J. Clin. Microbiol. · Sep 2012
Investigation of false-positive results given by the QuantiFERON-TB Gold In-Tube assay.
We investigated a sudden increase in the rate of positive QuantiFERON-TB Gold In-Tube results from 10% to 31% at a U. S. academic institution. ⋯ The underlying defect remains unknown. This finding warrants refinement of quality control programs by the manufacturer and users.
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J. Clin. Microbiol. · Aug 2012
Prevalence of Trichomonas vaginalis and coinfection with Chlamydia trachomatis and Neisseria gonorrhoeae in the United States as determined by the Aptima Trichomonas vaginalis nucleic acid amplification assay.
Our aim was to determine Trichomonas vaginalis prevalence using the Aptima Trichomonas vaginalis assay (ATV; Gen-Probe) and the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae coinfections in U. S. women undergoing screening for C. trachomatis/N. gonorrhoeae. Discarded urogenital samples from 7,593 women (18 to 89 years old) undergoing C. trachomatis/N. gonorrhoeae screening using the Aptima Combo 2 assay (Gen-Probe) in various clinical settings were tested with ATV. ⋯ Higher T. vaginalis prevalence in women of >40 years is probably attributed to the reason for testing, i.e., symptomatic status versus routine screening in younger women. Coinfections were relatively low. High T. vaginalis prevalence in all age groups suggests that women screened for C. trachomatis/N. gonorrhoeae, whether asymptomatic or symptomatic, should be screened for T. vaginalis.