Mechanisms of bacterial resistance to fluoro-quinolones may be grouped intothree principal categories: gene mutations of DNA topoisomerase Ⅱ (GyrA or GyrB), DNA topoisomeraseⅣ ( ParC or ParE), decrease of outer memb...Mechanisms of bacterial resistance to fluoro-quinolones may be grouped intothree principal categories: gene mutations of DNA topoisomerase Ⅱ (GyrA or GyrB), DNA topoisomeraseⅣ ( ParC or ParE), decrease of outer membrane permeation and upregulation of multi-drug effluxpump (active efflux system). Efflux pumps are transport proteins removing toxic substrates(including virtually all classes of clinically relevant antibiotics) from cells to the externalenvironment. These proteins exist in both Gram positive bacteria and Gram negative bacteria as wellas in fungi and mammalian (tumour) cells. It has been reported that alkaloid reserpine and carbonylcyanide m-chlorophenylhydrazone (CCCP) can inhibit NorA multi-drug efflux. In order to explore theuniversality of drug efflux in microorganisms, 85 strains of Acinetobacter baumannii (A. baumannii)were tested using reserpine and CCCP. The quinolone-resistant-determining region (QRDR) of gyrA andparC genes in 35 isolates of A. baumannii were amplified by polymerase chain reaction (PCR) andsequenced by DNA sequencer. The correlation between resistant mutation regularity and bacterial drugefflux were analysed.展开更多
文摘Mechanisms of bacterial resistance to fluoro-quinolones may be grouped intothree principal categories: gene mutations of DNA topoisomerase Ⅱ (GyrA or GyrB), DNA topoisomeraseⅣ ( ParC or ParE), decrease of outer membrane permeation and upregulation of multi-drug effluxpump (active efflux system). Efflux pumps are transport proteins removing toxic substrates(including virtually all classes of clinically relevant antibiotics) from cells to the externalenvironment. These proteins exist in both Gram positive bacteria and Gram negative bacteria as wellas in fungi and mammalian (tumour) cells. It has been reported that alkaloid reserpine and carbonylcyanide m-chlorophenylhydrazone (CCCP) can inhibit NorA multi-drug efflux. In order to explore theuniversality of drug efflux in microorganisms, 85 strains of Acinetobacter baumannii (A. baumannii)were tested using reserpine and CCCP. The quinolone-resistant-determining region (QRDR) of gyrA andparC genes in 35 isolates of A. baumannii were amplified by polymerase chain reaction (PCR) andsequenced by DNA sequencer. The correlation between resistant mutation regularity and bacterial drugefflux were analysed.
