| 10 strains Lactic acid bacteria were isolated from goat milk and it's products, infants and cows in Inner Mongolia, to compare with sensitive bacteria, The Minimum inhibitory concentration(MIC)of Lactic acid bacteria to fluorquinlones(Ofloxacin,Ciprofloxacin,Norfloxacin,Enrofloxacin) were determined by two-fold dilution, then the diameter of inhibition zone of Lactic acid bacteria to fluorquinlones were determined by Oxford plate.The 16srRNA of Lactic acid bacteria was amplified using primer which specially amplify the 16srRNA, then use fluorescence spectrophotometry and inhibitor of efflux pump, the existence of active efflux system in Lactic acid bacteria were corroborated by compared the intaking of ciprofloxacin in Lactic acid bacteria. Another mechanism of resistance in Lactic acid bacteria to fluorquinlones was determined, Quinolone Resistance Determining Regions (QRDR) of gyrA (topoisoneraseâ…¡DNA gyrase subnit A) and parC (topoisoneraseâ…£subnitA) were amplified using two pairs primers, then sequenced the PCR products of two Lactic acid bacteria to determined the exist of mutation in QRDR of gyrA and parC.All of the isolates were coherently resistive to fluorquinlones, the mechanism of resistance in Lactic acid bacteria. The mutation of gyrA gene are the primary mechanisms which response for resistance to fluroquinolones and efflux is also an important factor contributing to fluoroquinolones resistance of Lactic acid bacteria.
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