Journal of clinical microbiology
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J. Clin. Microbiol. · Nov 2013
Enhanced diagnostic yields of bacteremia and candidemia in blood specimens by PCR-electrospray ionization mass spectrometry.
A prospective study was performed to determine the value of direct molecular testing of whole blood for detecting the presence of culturable and unculturable bacteria and yeasts in patients with suspected bloodstream infections. A total of 464 adult and pediatric patients with positive blood cultures matched with 442 patients with negative blood cultures collected during the same period were recruited during a 10-month study. PCR amplification coupled with electrospray ionization mass spectrometry (PCR-ESI-MS) plus blood culture reached an overall agreement of 78.6% in the detection and species-level identification of bacterial and candidal pathogens. ⋯ Among the 15 culture-positive specimens in which PCR-ESI-MS detected additional bacterial or yeast species, 66.7% and 20.0% of the additional positive specimens by PCR-ESI-MS were judged to be truly or possibly bacteremic and/or candidemic, respectively. Direct analysis of blood samples by PCR-ESI-MS rapidly detects bacterial and yeast pathogens in patients with bloodstream infections. When used in conjunction with blood culture, PCR-ESI-MS enhances the diagnostics of septicemia by shortening test turnaround time and improving yields.
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J. Clin. Microbiol. · Sep 2013
New rapid scheme for distinguishing the subspecies of the Mycobacterium abscessus group and identifying Mycobacterium massiliense isolates with inducible clarithromycin resistance.
Mycobacterium abscessus (M. abscessus sensu lato, or the M. abscessus group) comprises three closely related taxa whose taxonomic statuses are under revision, i.e., M. abscessus sensu stricto, Mycobacterium bolletii, and Mycobacterium massiliense. We describe here a simple, robust, and cost-effective PCR-based method for distinguishing among M. abscessus, M. massiliense, and M. bolletii. Based on the M. abscessus ATCC 19977(T) genome, regions that discriminated between M. abscessus and M. massiliense were identified through array-based comparative genomic hybridization. ⋯ Interestingly, 2 isolates unequivocally identified as M. massiliense were shown to have a full-length erm(41) gene instead of the expected gene deletion and showed inducible clarithromycin resistance after 14 days. We propose using this PCR-based typing scheme combined with erm(41) PCR for straightforward identification of M. abscessus, M. massiliense, and M. bolletii and the assessment of inducible clarithromycin resistance. This method can be easily integrated into a routine workflow to provide subspecies-level identification within 24 h after isolation of the M. abscessus group.
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J. Clin. Microbiol. · Sep 2013
Isolation of nontuberculous mycobacteria (NTM) from household water and shower aerosols in patients with pulmonary disease caused by NTM.
It has been postulated that susceptible individuals may acquire infection with nontuberculous mycobacteria (NTM) from water and aerosol exposure. This study examined household water and shower aerosols of patients with NTM pulmonary disease. The mycobacteria isolated from clinical samples from 20 patients included M. avium (5 patients), M. intracellulare (12 patients), M. abscessus (7 patients), M. gordonae (1 patient), M. lentiflavum (1 patient), M. fortuitum (1 patient), M. peregrinum (1 patient), M. chelonae (1 patient), M. triplex (1 patient), and M. kansasii (1 patient). ⋯ NTM causing human disease can be isolated from household water and aerosols. The evidence appears strongest for M. avium, M. kansasii, M. lentiflavum, and M. abscessus. Despite a predominance of disease due to M. intracellulare, we found no evidence for acquisition of infection from household water for this species.
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J. Clin. Microbiol. · Aug 2013
Preliminary laboratory report of fungal infections associated with contaminated methylprednisolone injections.
In September 2012, the Centers for Disease Control and Prevention (CDC) initiated an outbreak investigation of fungal infections linked to injection of contaminated methylprednisolone acetate (MPA). Between 2 October 2012 and 14 February 2013, the CDC laboratory received 799 fungal isolates or human specimens, including cerebrospinal fluid (CSF), synovial fluid, and abscess tissue, from 469 case patients in 19 states. A novel broad-range PCR assay and DNA sequencing were used to evaluate these specimens. ⋯ Thirteen other mold species were identified among case patients, and four other fungal genera were isolated from the implicated MPA vials. The clinical significance of these other fungal species remains under investigation. The laboratory response provided significant support to case confirmation, enabled linkage between clinical isolates and injected vials of MPA, and described significant features of the fungal agents involved in this large multistate outbreak.