A Contribution of MdfA to Resistance to Fluoroquinolones in Shigella flexneri

초록

In this study, we measured the drug resistance conferred by mdfA mutations in two Shigella flexneri strains. A mutant in mdfA genes was constructed by polymerase chain reaction-based, one-step inactivation of chromosomal genes. The antimicrobial susceptibility of parent and mutant strains to fluoroquinolones was determined by minimal inhibitory concentration (MICs). The {up triangle, open}. mdfA mutants were somewhat more susceptible to fluoroquinolones than the parent strains. The low level changes in MICs of the {up triangle, open}. mdfA mutants suggest that mdfA contributed the fluoroquinolone resistance in S flexneri. This finding found that the increased expression level of an MdfA efflux pump mediated fluoroquinolone resistance, but it is not likely a major effecter of higher resistance levels. © 2011.

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