RFLP patterns and risk factors for recent tuberculosis transmission among hospitalized tuberculosis patients in Rio de Janeiro, Brazil

Abstract

Isolates of Mycobacterium tuberculosis from 120 tuberculosis patients seen in the 12 months ending September 1994 at 2 tertiary-care centres in Rio de Janeiro were characterized by IS6110 restriction fragment length polymorphism (RFLP) analysis. Ninety-seven patients (81%) had isolates with unique RFLP patterns, while 23 patients (19%) had isolates that belonged to 11 different RFLP cluster patterns. The strains from the latter patients were distributed among 1 group of 3 patients and 10 groups of 2 patients each. The cluster-pattern strains were not associated with gender, age, HIV infection, type of residence, living in shelter, homelessness or previous history of tuberculosis. However, clustering was strongly associated with multidrug resistance (P = 0.006). These data suggest that recent exogenous transmission may be important for the development of new cases of multidrug-resistant disease in patients attending tertiary-care centres in Rio de Janeiro, Brazil.

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

“…These results agree partially with those published by other Brazilian authors [7,27]. In our study, HIV infection was not associated with isolate clustering, although 48.3% of the patients were HIV positive.…”

“…Our results agree with previous works [7,27,32] utilizing the detection of insertion element IS6110 in Brazilian M. tuberculosis isolates, which demonstrated that the number of this element per genome may vary (2-12 copies per genome). Our results also demonstrate that most of the isolates may be allocated to two main clusters.…”

“…In the last years, considerable efforts have been made to precise the epidemiology and characteristics of M. tuberculosis strains isolated in different regions of Brazil [7,[24][25][26][27][28][29][30][31]. Some Brazilian authors [26,27,29,32] demonstrated the usefulness of the IS6110-restriction fragment length polymorphism for typing Brazilian M. tuberculosis strains, but Ferreira et al [24] were the first to apply it to determine strain types in female inmate populations in São Paulo City, Brazil.…”

“…Some Brazilian authors [26,27,29,32] demonstrated the usefulness of the IS6110-restriction fragment length polymorphism for typing Brazilian M. tuberculosis strains, but Ferreira et al [24] were the first to apply it to determine strain types in female inmate populations in São Paulo City, Brazil. Ferreira et al [24] suggested that in 50% inmates infection was a reactivation process of a previous latent infection, while in the 50%, TB was transmitted within prison (exogenous infection).…”

Phenotypic and genotypic variant of MDR-Mycobacterium tuberculosis multiple isolates in the same tuberculosis episode, Rio de Janeiro, Brazil

“…In a retrospective study carried out to evaluate indicators of TB risk transmission, where 63.5% of patients were admitted to the hospital through the Emergency Room, in 27.5% of them the interval between admission and sputum collection exceeded 12 h. This delay in isolation was correlated with diagnosis of TB at admission and lower bacillary load in the sputum (16). In previous Brazilian MDR case studies, there was a significant association with clustering, suggesting that at tertiary care hospitals MDR cases may result from new transmission of primary resistant organisms (17). According to this information, a patient could be infected with one genetic pattern of MDR strain transmitted through the health facilities where he was admitted and the variant pattern found was related to an event of microevolution through IS6110 transposition over time.…”