Estudo de fatores relacionados ao controle da tuberculose: resistência às drogas, transmissão e suscetibilidade do hospedeiro. / Study of factors related to the control of tuberculosis: resistance to drugs, transmission and host susceptibility.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Tuberculosis resurged in the 90s after having been considered to be under control and is now a serious public health problem with social and economic ramifications. To understand the factors involved in the transmission and the disease, it is necessary to understand the three fundamentals of the disease: the environment, bacillus and host. This work evaluates these three important aspects of the epidemiology of tuberculosis in two municipalities in the metropolitan region of Recife-PE. In the town of Cabo de Santo Agostinho, we characterized the pattern of the development of resistant strains and their associated factors. The frequency of primary and acquired resistance to any drug was 14% and 50%, respectively, while the frequency of primary and acquired multidrug resistance was 8.3% and 40%, respectively. Previous treatment for tuberculosis and abandonment of treatment were risk factors for primary resistance to drugs. Among persons with Isoniazid- and Rifampicin-resistant strains, the levels of primary and acquired resistance were quite, making tuberculosis control in Cabo quite difficult. The transmission pattern of tuberculosis was defined by using by spoligotyping to genotype strains. A total of 40 distinct patterns were observed: one pattern with 9 isolates, three patterns with 5 isolates each, three other patterns with 4 isolates, two patterns with 3 isolates, five patterns with 2 isolates each, and 26 patterns with 1 isolate alone. Geographical analysis of cases residing in Cabo compared with those evaluated at the post of Health in Lessa de Andrade in Recife (a reference health service for greater Pernambuco) revealed that both municipalities shared common isolates. In Recife, the role of genetic markers (HLA) of host predisposition to tuberculosis was evaluated among persons who live in the same house as index cases. Of the 257 subjects studied, 54 persons (reference cases) were not related to the index case but shared their household. Among the 203 subjects related to the index case, the relative risk for developing tuberculosis, depending on degree of relationship, was 1.22 (95%CI :0.75-1 .99) for first-degree, 1.13 (95%CI :0.63-2 .03) for second degree, and 1.11 (95%CI :0.44-2 .78) for third degree when compared with the 54 afore-mentioned reference cases. Frequency analysis of HLA class II alleles was conducted separately between the 77 individuals who had tuberculosis and the 119 individuals with no history of tuberculosis. We did not find any allele associated with susceptibility to illness for tuberculosis. However, the allele DRB5*01 (OR= 0.45; 95%CI= 0.20-0.98; p= 0.0441) appears linked to resistance to tuberculosis and the allele DRB3*02 (OR= 0.59; 95%CI= 0.32-1.08; p= 0.0905) shows a trend of association with resistance to develop tuberculosis. A more complete understanding of M. Tuberculosis resistant strains and their genetic polymorphisms, as well as the host susceptibility in certain population groups, allow us to better assess the mechanisms of disease transmission and ultimately contribute to the control of tuberculosis.

ASSUNTO(S)

resistência a medicamentos hla antigens risk factors ciencias da saude humanos tuberculose drug resistance antígenos hla genótipo genotype tuberculosis fatores de risco

ACESSO AO ARTIGO

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