ABSTRACT
Abstract INTRODUCTION The prevalence of hematogenous dissemination of mycobacteria is high in immunosuppressed patients. The isolation of mycobacteria in culture remains the standard procedure. METHODS This is a cross-sectional study based on the results of solid (Löwenstein-Jensen medium) and semi-automated liquid (BACTEC 9240) blood cultures, obtained from the Lacen-GO database. RESULTS The implementation of a semi-automated procedure resulted in an increase of 61.5% and 350.0% in the positive results for Mycobacterium tuberculosis complex and nontuberculous mycobacteria, respectively. This technique also accelerated the detection of positive results. CONCLUSIONS Semi-automated liquid blood culture showed a better performance in the diagnosis of mycobacteremia.
Subject(s)
Humans , Bacteriological Techniques/methods , Automation, Laboratory/methods , Mycobacterium/isolation & purification , Reagent Kits, Diagnostic , Time Factors , Cross-Sectional Studies , Sensitivity and Specificity , Culture MediaABSTRACT
Atualmente, o controle da tuberculose é dependente de vários fatores tais como rápido diagnóstico, terapia adequada e meios de evitar futuras transmissões. Assim, a caracterização de linhagens de Mycobacterium tuberculosis por tipagem molecular por meio da técnica de RFLP-IS6110 representa uma contribuição primordial e tem sido amplamente utilizada nos estudos de genotipagem para que sejam traçadas cadeias de transmissão. No entanto, por causa da complexidade desta técnica e da dificuldade de interpretação dos dados, outras técnicas têm sido propostas. Entre elas, destaca-se o estudo do número variável de unidades repetitivas (MIRU-VNTR) indicado como novo padrão de genotipagem. O presente estudo teve como objetivo analisar as técnicas de RFLP-IS6110 e 15 loci MIRU-VNTR em isolados de pacientes atendidos no município de Goiânia, Goiás. Para isso, foram caracterizados geneticamente os isolados a fim de se estabelecerem possíveis ligações epidemiológicas entre os casos da doença. Também fez-se a comparação entre os resultados encontrados pelas duas técnicas e o cenário do Brasil. Os dados demonstraram que a técnica de 15 loci MIRU-VNTR discriminou mais os isolados que a técnica de RFLP-IS6110. Não foi encontrada associação epidemiológica entre os pacientes estudados. Os resultados validaram o uso da técnica 15 loci MIRU-VNTR para tipagem molecular de M. tuberculosis por apresentar maior poder discriminatório, boa eficiência para caracterizar geneticamente os isolados em Goiânia-GO, podendo, portanto, ser um método usado em estudo epidemiológico isolado ou em conjunto com outras técnicas...
Molecular analysis of Mycobacterium tuberculosis isolated from patients in Goiânia, Brazil, using RFLP-IS6110 and 15 loci MIRU-VNTR techniques.Currently, tuberculosis control is dependent on several factors, such as rapid diagnosis, appropriate therapy and measures to prevent future transmission. Thus, the characterization of strains of Mycobacterium tuberculosis by molecular typing using RFLP-IS6110, provides a major contribution, and has been widely used in genotyping studies in order to trace transmission pathways. However, due to the complexities of the technique and data interpretation, other techniques have been proposed. Among them, the study of the variable number of repeat units (MIRU-VNTR) has been indicated as a new standard method. This study aimed to apply and compare the RFLP-IS6110 and 15 loci MIRU-VNTR techniques for the analysis of isolates from tuberculosis patients treated in Goiânia, Brazil, in order to establish possible molecular epidemiological links between cases of the disease, and also to compare the results found by both techniques against the wider situation in Brazil. The results showed that 15 loci MIRU-VNTR discriminated between the isolates better than the RFLP-IS6110. No epidemiological link was observed among the patients studied. The results validate the use of the 15 loci MIRU-VNTR technique for molecular typing of M. tuberculosis, as it showed greater discriminatory power with good efficiency to genetically characterize the isolates in Goiânia, Goiás. This can be used in epidemiological studies alone or in conjunction with other molecular techniques...
Subject(s)
Humans , Molecular Epidemiology , Mycobacterium tuberculosis , Minisatellite Repeats , Tuberculosis , GenotypeABSTRACT
Drug resistance is one of the major concerns regarding tuberculosis (TB) infection worldwide because it hampers control of the disease. Understanding the underlying mechanisms responsible for drug resistance development is of the highest importance. To investigate clinical data from drug-resistant TB patients at the Tropical Diseases Hospital, Goiás (GO), Brazil and to evaluate the molecular basis of rifampin (R) and isoniazid (H) resistance in Mycobacterium tuberculosis. Drug susceptibility testing was performed on 124 isolates from 100 patients and 24 isolates displayed resistance to R and/or H. Molecular analysis of drug resistance was performed by partial sequencing of the rpoB and katGgenes and analysis of the inhA promoter region. Similarity analysis of isolates was performed by 15 loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing. The molecular basis of drug resistance among the 24 isolates from 16 patients was confirmed in 18 isolates. Different susceptibility profiles among the isolates from the same individual were observed in five patients; using MIRU-VNTR, we have shown that those isolates were not genetically identical, with differences in one to three loci within the 15 analysed loci. Drug-resistant TB in GO is caused by M. tuberculosis strains with mutations in previously described sites of known genes and some patients harbour a mixed phenotype infection as a consequence of a single infective event; however, further and broader investigations are needed to support our findings.