ABSTRACT
This study aimed to propose and evaluate a drug susceptibility testing (DST) using the 2,3,5-triphenyl tetrazolium chloride (TTC) as a colorimetric indicator against Mycobacterium abscessus complex (MABC), M. avium complex (MAC), and M. kansasii strains, main nontuberculous mycobacteria (NTM) of clinical relevance. Our results demonstrated that the assay using TTC and the broth microdilution method recommended by the Clinical and Laboratory Standards Institute had essential agreement above 91%, 92%, and 100%, for drugs tested against MABC, MAC, and M. kansasii strains, respectively. Categorical agreement above 91% was obtained for most drugs tested against MABC, except to cefoxitin (76.5%). For drugs tested against MAC and M. kansasii, categorical agreement above 92% and 100% was observed, respectively. TTC showed to be a promising colorimetric indicator of growth to be used in DST for NTM, allowing an easier reading of results.
Subject(s)
Mycobacterium Infections, Nontuberculous , Mycobacterium abscessus , Mycobacterium tuberculosis , Humans , Nontuberculous Mycobacteria , Mycobacterium Infections, Nontuberculous/microbiology , Anti-Bacterial Agents/therapeutic use , Chlorides , Colorimetry , Microbial Sensitivity TestsABSTRACT
To evaluate the genetic diversity and clustering rates of M. tuberculosis strains to better understand transmission among persons deprived of liberty (PDL) in Rio Grande do Sul (RS), southern Brazil. This is a cross-sectional study, including strains of M. tuberculosis isolated from PDL, stored at the Central Laboratory of RS, in the period from 2013 to 2018. The molecular characterization was performed using the MIRU-VNTR 15 loci method. A total of 598 M. tuberculosis strains were genotyped, and 37.5% were grouped into 53 clusters. Cluster sizes ranged from 2 to 34 strains. The largest cluster of the study had strains from 34 PDL, and 58.8% of the PDL of this cluster were in P01. Among the clusters formed, in 60.3%, there was at least one strain from P01. The most common strains in RS were LAM (53.2%) and Haarlem (31.1%). The LAM strain was the most likely to form clusters, and Haarlem was associated with anti-TB drug resistance. This was translational research, and the results can collaborate with the TB control programs, leading to improved strategies that allow the reduction of the TB burden in prisons.
