Drug resistance of Mycobacterium tuberculosis induced by ethambutol in vitro

Objective To study the drug resistance of Mycobacterium tuberculosis induced by ethambutol in vitro,and to guide the selection and use of anti-tuberculous agents in clinical practice.Methods The induced experiments of drug resistance on Mycobacterium tuberculosis H_(37)Rv by ethambutol in vitro were performed.The induced strains and 34 ethambutol-resistant strains were analyzed by polymerase chain reaction-single stranded conformation polymorphism(PCR-SSCP) and PCR-direct sequencing (PCR-DS) techniques.Results The SSCP spectrum in 12 ethambutol-resistant strains and the induced strains of eighth generation was different from that of wild type H_(37)Rv.PCR-DS showed the mutation from ATG to GTG at codon 306 of embB.Conclusion The acquired ethambutol-resistance could be induced by long term exposure to the low level of intermittent antibacterial agents.