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Mycobacterium tuberculosis resistance profiles in index and secondary TB cases from the same household

2018; Elsevier BV; Linguagem: Inglês

10.1183/13993003.congress-2018.pa2687

1873-281X

Elena Chesov, Greta Bălan, Nelly Ciobanu, Dumitru Chesov, Valeriu Crudu,

Infectious Diseases and Tuberculosis

Background: Resistance profile of the index case is recommended to be considered in treatment decision in close contacts with active TB, pending drug sensitivity test (DST) results. However, the agreement between index and secondary TB cases DST could be not enough accurate in special in settings with a high rate of infection transmission. Aim: To compare the resistance profiles of M. tuberculosis in index and secondary TB cases registered in the same household. Methods: We performed a retrospective study to compare routine phenotypic DST results in M. tuberculosis strains isolated at the time of diagnosis from index and secondary TB case registered in the same household. Results: The DST results of 92 pairs of index and secondary TB cases were compared. A similar resistance profile for the first line TB drugs was found in 2/3 of the analyzed pairs. The rate of similar isoniazid and rifampicin resistance profiles in household outbreaks with MDR TB index case was 90%, while in those with sensitive TB index cases - 65%. The rate of similar resistance profile in outbreaks with positive sputum smear index case does not differ significantly from that in the outbreaks with smear negative index case. At the same time for the second line TB drug the similarity rate was 59% for injectables/fluoroquinolones and 39% for ethionamide/cycloserine. Conclusions: Comparison of the resistance profile of M. tuberculosis strains isolated in index and secondary TB cases from the same household revealed a significant rate of divergence. That suggest a potential high rate of TB transmission in the community outside the household. Molecular epidemiology studies are required to prove the phenomenon.