Usefulness of the nitrate reductase method to detect resistance to second-line anti-tuberculosis drugs

[摘要] Introduction: The increase of multidrug resistant and extensively drug resistant tuberculosis underlines the urgent need to obtain early results of Mycobacterium tuberculosis susceptibility both to first and second line antituberculosis drugs in order to avoid dissemination of resistant isolates.Objective:The aim of this research was to compare the performance of the nitrate reductase assay and the proportion method for to detect the susceptibility to second line antituberculosis drugs in multidrug resistant clinical isolates of M. tuberculosis.Methods: The susceptibility to ofloxacin, kamamycin and capreomycin of 34 M. tuberculosis multidrug resistant isolates was investigated using the proportion method in Löwenstein-Jensen and the nitrate reductase assay.Results: Three isolates were identified as extensively drug resistant by both methods. The results of the nitrate reductase assay were obtained between 7-14 days achieving 100 %, 90.0 % and 77.8 % of sensitivity for ofloxacin, kamamycin and capreomycin, respectively while specificity was higher than 95.0 % and kappa value was higher to 0,85 for all drugs.Conclusion:The nitrate reductase assay represents a useful tool for the rapid identification of extensively drug resistant tuberculosis in low resources setting.

[学科分类] 传染病学

[关键词] tuberculosis;nitrate reductase assay;second line antituberculosis drugs