Laboratory-based study of drug resistance and genotypic profile of multidrug-resistant tuberculosis isolates in Salvador, Bahia, Brazil.

BACKGROUND: Surveillance of multidrug resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB) is essential to guide disease dissemination control measures. Brazil contributes to a significant fraction of tuberculosis (TB) cases worldwide, but only few reports addressed MDR/XDR-TB in the country. METHODS: This cross-sectional, laboratory-based study describes the phenotypic resistance profiles of isolates obtained between January 2008 and December 2011 in Bahia, Brazil, and sociodemographic, epidemiological, and clinical characteristics (obtained from mandatory national registries) of the corresponding 204 MDR/XDR-TB patients. We analyzed the mycobacterial spoligotyping and variable number of tandem repeats of mycobacterial interspersed repetitive units in 12-loci profiles obtained from Salvador. RESULTS: MDR/XDR-TB patients were predominantly male, had a median age of 43 years, belonged to black ethnicity, and failed treatment before MDR-TB diagnosis. Nearly one-third of the isolates had phenotypic resistance (evaluated by mycobacteria growth indicator tube assay) to second-line anti-TB drugs (64/204, 31%), of which 22% cases (14/64) were diagnosed as XDR-TB. Death was a frequent outcome among these individuals and was associated with resistance to second-line anti-TB drugs. Most isolates successfully genotyped belonged to the Latin-American Mediterranean (LAM) Family, with an unprecedented high proportion of LAM10-Cameroon subfamily bacilli. More than half of these isolates were assigned to a unique cluster by the genotyping methods performed. Large clusters of identical genotypes were also observed among LAM SIT42 and SIT376 strains. CONCLUSIONS: We highlight the need for strengthening local and national efforts to perform early detection of TB drug resistance and to prevent treatment discontinuation to limit the emergence of drug-resistant strains.

Laboratory-based study of drug resistance and genotypic profile of multidrug-resistant tuberculosis isolates in Salvador, Bahia, Brazil

Abstract Background: Surveillance of multidrug resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB) is essential to guide disease dissemination control measures. Brazil contributes to a significant fraction of tuberculosis (TB) cases worldwide, but only few reports addressed MDR/XDR-TB in the country. Methods: This cross-sectional, laboratory-based study describes the phenotypic resistance profiles of isolates obtained between January 2008 and December 2011 in Bahia, Brazil, and sociodemographic, epidemiological, and clinical characteristics (obtained from mandatory national registries) of the corresponding 204 MDR/XDR-TB patients. We analyzed the mycobacterial spoligotyping and variable number of tandem repeats of mycobacterial interspersed repetitive units in 12-loci profiles obtained from Salvador. Results: MDR/XDR-TB patients were predominantly male, had a median age of 43 years, belonged to black ethnicity, and failed treatment before MDR-TB diagnosis. Nearly one-third of the isolates had phenotypic resistance (evaluated by mycobacteria growth indicator tube assay) to second-line anti-TB drugs (64/204, 31%), of which 22% cases (14/64) were diagnosed as XDR-TB. Death was a frequent outcome among these individuals and was associated with resistance to second-line anti-TB drugs. Most isolates successfully genotyped belonged to the Latin-American Mediterranean (LAM) Family, with an unprecedented high proportion of LAM10-Cameroon subfamily bacilli. More than half of these isolates were assigned to a unique cluster by the genotyping methods performed. Large clusters of identical genotypes were also observed among LAM SIT42 and SIT376 strains. Conclusions: We highlight the need for strengthening local and national efforts to perform early detection of TB drug resistance and to prevent treatment discontinuation to limit the emergence of drug-resistant strains.

Detection of Drug Resistant Mycobacterium Tuberculosis Strains Using Kit SIRE Nitratase®: a Multicenter Study

Abstract (1) Background: The Commercial Kit SIRE Nitratase® PlastLabor, is a drug susceptibility test kit used to detect Mycobacterium tuberculosis resistance to first-line TB treatment drugs. The present study aimed at evaluating its performance in a multicenter study. (2) Methods: To determine its accuracy, the proportion methods in Lowenstein Jensen medium or the BACTECTMMGITTM960 system was used as a gold standard. (3) Results: The study revealed that the respective accuracies of the kit with 190 M. tuberculosis clinical isolates, using the proportion methods in Lowenstein Jensen medium or BACTECTMMGITTM960 system as a gold standard, were 93.9% and 94.6%, 96.9% and 94.6%, 98.0% and 97.8%, and 98.0% and 98.9%, for streptomycin, isoniazid, rifampicin, and ethambutol, respectively. (4) Conclusion: Thus, the kit can rapidly screen resistance to streptomycin, isoniazid, rifampicin, and ethambutol. Additionally, it does not require sophisticated equipment; hence, it can be easily used in the laboratories of low and middle income countries.

First detection of Mycobacterium triplex in Latin America.

In this study we describe the first isolation of Mycobacterium triplex in Latin America. This species causes infections in humans, with very few reports from around the world. We isolated two sputum specimens of a patient with a 6-year history of human immunodeficiency and tuberculosis treatment failure. All tests used confirmed M. triplex and the patient responded well to drug therapy for 18months.

Description of a new Mycobacterium intracellulare pattern of PCR restriction enzyme analysis of hsp65 gene.

This work comprises 9 pulmonary nontuberculous mycobateria isolates obtained from sputum of 4 different patients from Brazil. The sequencing and phylogenetic analysis allowed their accurate identification as Mycobacterium intracellulare. We report a mutation at position 453 creating a new HaeIII cutting site and, therefore, a new PRA-hsp65 M. intracellulare profile.

Mycobacterium fragae sp. nov., a non-chromogenic species isolated from human respiratory specimens.

Three isolates of a slow-growing, non-chromogenic mycobacterium were grown from three sputum samples of a patient from the north-eastern Ceará state in Brazil. Identification at species level could not be obtained with PCR restriction analysis of the hsp65 gene. In order to characterize the isolates we carried out phenotypic and genotypic tests. We sequenced the nearly complete 16S rRNA gene and obtained partial sequences of the hsp65 (encoding the hypervariable region of the 65 kDa heat-shock protein) and rpoB (encoding the beta-subunit of RNA polymerase) genes. The three isolates turned out to be identical and most closely related to the species Mycobacterium celatum and Mycobacterium kyorinense. The results, however, showed significant differences between these species and the isolates studied, which led us to consider them members of a novel species for which we propose the name Mycobacterium fragae. The type strain is HF8705(T) ( = Fiocruz-INCQS/CMRVS P4051(T) = DSM 45731(T)).

First isolation of Mycobacterium kyorinense from clinical specimens in Brazil.

In this article, the first isolation of Mycobacterium kyorinense specimens in Brazil is described. M. kyorinense is a recently identified species, with a few strains reported only in Japan. The Brazilian isolates were initially identified as Mycobacterium celatum by PCR restriction enzyme pattern analysis (PRA) with hsp65. However, biochemical tests indicated the same profile of M. kyorinense and distinguished them from M. celatum and Mycobacterium branderi. The sequencing of the hsp65, rpoB, and 16S rRNA genes allowed the accurate identification of isolates as M. kyorinense.