Correlation between drug-resistance of sensitive strain of Shigella flexneri and mutation of marOR gene

Objective To induce multidrug resistance of the sensitive strain of Shigella flexneri and to study the multidrug resistance regulating gene mutations.Methods Clinical sensitive Shigella flexneri strain was induced into anti-drug strain by 1/2 minimum inhibitive concentration(MIC) induced trails of four antibiotics.MarOR gene in sensitive and induced anti-multidrug strain was amplified with polymerase chain reaction(PCR).The PCR products were sequenced and compared.Results Induced anti-multidrug strain of Shigella flexneri was obtained successfully.The strain was resistant to gentamycin(GF),norfloxacin(NOR),cotrimoxazole(SMZ),and cefalotin(CF).DNA sequence analyses of marOR in sensitive and induced anti-multidrug strain revealed seven point mutations.Conclusion The marOR gene mutations may play an important role in the regulation of multi-drug resistance in Shigella spp.