Canadian multicenter laboratory study for standardized second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis.

The purpose of this study was to establish a standardized protocol for second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis using the Bactec MGIT 960 system in Canadian laboratories. Four Canadian public health laboratories compared the susceptibility testing results of 9 second-line antimicrobials between the Bactec 460 and Bactec MGIT 960 systems. Based on the data generated, we have established that the Bactec MGIT 960 system provides results comparable to those obtained with the previous Bactec 460 method.

Aging, COPD, and other risk factors do not explain the increased prevalence of pulmonary Mycobacterium avium complex in Ontario.

Background: The cause of observed increases in pulmonary Mycobacterium avium complex (pMAC) isolation and disease is unexplained. To explore possible causes of the increase in pMAC isolation and disease prevalence in Ontario, Canada, we studied age and other population-level risk factors.

Methods: We determined age and sex of patients with pMAC disease between 2003 and 2008.

Isolation prevalence of pulmonary nontuberculous mycobacteria in Ontario in 2007.

Background: The reported prevalence of pulmonary nontuberculous mycobacteria (NTM) infections is increasing.

Objective: To determine the 'isolation prevalence' of NTM in 2007 and compare it with previously published research that examined the increasing rates of isolation of NTM from clinical pulmonary specimens between 1997 and 2003.

Methods: Isolation prevalence was investigated retrospectively by reviewing a cohort of all positive pulmonary NTM culture results from the Tuberculosis and Mycobacteriology Laboratory, Public Health Laboratory (Toronto, Ontario) in 2007, which identifies at least 95% of NTM isolates in Ontario.

Nontuberculous mycobacterial lung infections in Ontario, Canada: clinical and microbiological characteristics.

Study Objectives: The aim of this study was to determine gender and clinical phenotype frequencies in pulmonary nontuberculous mycobacterial (NTM) infection and the frequency of disease in NTM isolates.

Design: The study is a retrospective observational cohort study of two overlapping cohorts: population cohort and clinical cohort. Setting The study was conducted at the University Health Network and Ontario Mycobacteriology Laboratory in Toronto, Ontario, Canada.

Potential for erroneous results indicating resistance when using the Bactec MGIT 960 system for testing susceptibility of Mycobacterium tuberculosis to pyrazinamide.

During susceptibility testing of 743 isolates of Mycobacterium tuberculosis to pyrazinamide (PZA) using the Bactec 960 system, 57 (7.7%) isolates showed PZA resistance. Repeat testing of resistant isolates with the Bactec 460 reference method confirmed 33 (4.

Non-tuberculous mycobacteria in children with cystic fibrosis: isolation, prevalence, and predictors.

Background: Screening for non-tuberculous mycobacteria (NTM) is recommended for adults with cystic fibrosis (CF). The relevance of this organism in North American pediatric CF patients is unclear as there is limited NTM prevalence data for children. We aimed to determine the prevalence of NTM in children with CF from a single expectorated sputum and identify clinical predictors of NTM isolation.

Molecular characterization of drug-resistant Mycobacterium tuberculosis isolates from Ontario, Canada.

Objectives: Ontario bears the greatest burden of tuberculosis in Canada, with 40% of all cases and 60% of multidrug-resistant cases. The purpose of this study was to genotypically characterize isoniazid- and rifampicin-resistant isolates and compare these results with phenotypic drug susceptibility testing data. This is the first Canadian study to examine gene mutations that contribute to multidrug-resistant tuberculosis.

Mycobacterium tuberculosis in Ontario, Canada: Insights from IS6110 restriction fragment length polymorphism and mycobacterial interspersed repetitive-unit-variable-number tandem-repeat genotyping.

A collection of 1,308 clinical Mycobacterium tuberculosis isolates from Ontario, Canada, was genotyped by IS6110 restriction fragment length polymorphism (RFLP) and mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analysis. RFLP or >12 MIRU-VNTR loci were necessary for resolution of Indo-Oceanic strains. The low clustering rate and high strain diversity indicate that, in Ontario, most tuberculosis results from reactivation of latent infections.

Comparison of in-house and commercial 16S rRNA sequencing with high-performance liquid chromatography and genotype AS and CM for identification of nontuberculous mycobacteria.

Sequencing of the 16S gene or other targets and line probe assay are in wide use for the identification of nontuberculous mycobacteria. We compared in-house and commercial sequencing with 3 sequence databases against high-performance liquid chromatography (HPLC) and line probe assay (HAIN Genotype AS and CM) for the identification of 84 reference, clinical, and unique strains representing 41 species. Consensus of methods was used as reference standard.

Hot tub lung mimicking classic acute and chronic hypersensitivity pneumonitis: two case reports.

Pulmonary disease in otherwise healthy patients can occur by secondary exposure to nontuberculous mycobacteria from hot tubs. The pathology of hot tub lung may be related to an infection, a hypersensitivity reaction or both. Previous reports of hot tub lung have highlighted distinct pathological features that have distinguished this entity from classic hypersensitivity pneumonitis.

Isolation prevalence of pulmonary non-tuberculous mycobacteria in Ontario, 1997 2003.

Background: The prevalence of pulmonary non-tuberculous mycobacteria (NTM) infection is reportedly increasing. A study was undertaken of the "isolation prevalence" of pulmonary NTM in Ontario, Canada between 1997 and 2003 and the frequency of pulmonary NTM "disease".

Methods: In a retrospective cohort, the "isolation prevalence" was studied by reviewing all positive NTM culture results from the Tuberculosis and Mycobacteriology Laboratory, Ministry of Health and Long-Term Care in Toronto from 1997 to 2003.

Outbreak of acupuncture-associated cutaneous Mycobacterium abscessus infections.

Background: Cutaneous atypical mycobacterial infections have been increasingly described in association with cosmetic and alternative procedures.

Objective: We report an outbreak of acupuncture-associated mycobacteriosis. Between April and December 2002, 32 patients developed cutaneous mycobacteriosis after visiting an acupuncture practice in Toronto, Canada.

Mycobacterium lacus sp. nov., a novel slowly growing, non-chromogenic clinical isolate.

A strain of a novel non-chromogenic mycobacterium was isolated from synovial tissue from a 68-year-old female with bursitis of her right elbow. The slowly growing strain had a unique PCR-restriction enzyme analysis (PRA) profile of the hsp65 gene and 16S rRNA gene sequence in comparison with other mycobacterium species. The most closely related species, as determined by 16S rRNA gene sequence analysis, are Mycobacterium malmoense, Mycobacterium marinum, Mycobacterium ulcerans and members of the Mycobacterium tuberculosis complex.

Method for inactivating and fixing unstained smear preparations of mycobacterium tuberculosis for improved laboratory safety.

The inactivation of smears that contain Mycobacterium tuberculosis for microscopy before removal of the material from a biosafety cabinet is an important safety factor in preventing the potential transmission of tuberculosis to laboratory workers. The fixing and inactivating properties of heat flaming, 70% ethanol, and 1, 3, and 5% phenol in ethanol for smears containing M. tuberculosis were investigated.

Phenotypic and molecular characterization of clinical isolates of Mycobacterium elephantis from human specimens.

Eleven strains of a rapidly growing mycobacterium were isolated from patient specimens originating from various regions of the province of Ontario, Canada, over a 2-year period. Unique high-performance liquid chromatography (HPLC) and PCR-restriction enzyme pattern analysis (PRA) profiles initially suggested a new Mycobacterium species, while sequencing of the 16S rRNA gene revealed a sequence match with Mycobacterium sp. strain MCRO 17 (GenBank accession no.