Molecular genotyping and epidemiology of Mycobacterium tuberculosis isolates obtained from inmates of correctional institutions of Campinas, Southeast Brazil

The objective of this study was to investigate the possible transmission of tuberculosis among 39 inmates with positive Mycobacterium tuberculosis smears in four correctional institutions located in Campinas City, SP, Brazil over a 19-month period. Fifty-one M. tuberculosis isolates from these inmates were characterized according to the number of IS6110 insertion elements present in their genomic DNA. The number of insertion elements in M. tuberculosis isolates varied from two to twelve. The dendrogram of similarity resulted in the grouping the isolates in six main clusters. These results, associated to epidemiological data, suggested the transmission of tuberculosis among inmates of the same and different institutions inmates. Univariate analysis of epidemiological data (total delay for beginning of treatment, previous treatment, and HIV status) and clustering occurrence showed that only 'previous treatment' (OR = 7.65, p = 0.032) was associated with the possible transmission of tuberculosis in the studied prisons.