RESUMO
Screening of 127 isoniazid (INH)-resistant Mycobacterium tuberculosis isolates from Singapore for mutations within the dfrA and inhA genes revealed mutations in 0 and 5 (3.9%) isolates respectively, implying that mutations in dfrA do not contribute to the detection of INH-resistant M. tuberculosis and that mutations within inhA are rare. Thirty-seven (29%) of the 127 isolates had no mutations in any of the genes implicated in INH resistance (katG, kasA, and ndh; inhA and ahpC promoters), suggesting that there are new INH targets yet to be discovered.
Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Isoniazida/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Oxirredutases/genética , MutaçãoRESUMO
Genetic analysis of the embB gene revealed mutations in 17 (68%) of 25 ethambutol (EMB) resistant isolates (M306I, M306V, M306L, Q497R) but also in 4 (20%) of 20 EMB-susceptible isolates of Mycobacterium tuberculosis, namely, an ATG-->ATM substitution resulting in M306I, G406N, and the novel alterations M423I and A659T.