Investigation Of Drug Resistance On Phenicols And Quinolone By Efflux Pump Inhibitors

Vibrio species has become an important pathogen of restricting the development of mariculture in China in recent years.With the progress of the society,the problem of drug resistance is becoming more and more serious.In order to explore the mechanism of the drug resistance,we should find a better solution to solve it.The Vibrio strains of florfenicol low sensitive from several aquaculture animals(such as Pacific white shrimp,Swimming crab,Cynoglossus semilaevis,Portunus trituberculatus,etc).And aquaculture environment(including sediment and pond water etc.)In three areas of Shanghai,Jiangsu and Shandong.The agar dilution method recommmended by CLSI(2010)was developed for the determination of sensitivity of these strains to the 16 kinds of antimicrobial agents.Using PCR amplification sequencing method to detect the antimicrobial resistance genes in these strains.The effects of the four efflux pump inhibitors on the change of the MIC value in resistance of phenicols and quinolone has been conducted..120 strains of florfenicol low sensitive Vibrio species include Vibrio alginolyticus44 strains(36.67%),Vibrio scophthalmus 42 strains(35.00%),Vibrio harveyi 16 strains(13.33%),Vibrio parahaemolyticus 14 strains(11.67%),Vibrio vulnificus and Vibrio anguillarum are 2 strains.The results of the resistance rates of 16 drugs showed that the resistance rates of Sulfonamides and phenicols are higher than others.Determination of drug sensitivity of 120 strains,the results showed that 61 strains are resistant to chloramphenicol,118 strains resistant to florfenicol.There are 60 strains resistant to the two drugs.Sulfamethoxazole and Sulfamethoxazole Trimethoprim are also have high antimicobial resistance ratio,the antimicrobial resistance rates of quinolone are not high(Ciprofloxacin,17.5%;Norfloxacin,16.67%;Enrofloxacin,32.5%).The antimicrobial resistance rates of Oxytetracycline,Erythromycin,Neomycinsulphate are also greater than 50%.All 120 strains are sensitive to Ceftriaxone?Cefepime and Meropenem.The detection of antimicribial resistance genes showed that phenicols resistance genes flor could be detected in 118 vibrio strains,the detection rate of cat2 and cat3 were 13.33% and 7.5%;sulfonamides resistance gene sul1 and sul2 were 7.5% and6.67%;aminoglycoside resistance gene strA?strB?aad?aacA were 9.17%?10.83%?3.33% and 5%;?-lactams resistance gene TEM and carB were 1.67% and5.83%;tetracyclines resistance gene tetB was 3.33%;quinolone resistance genes qnrA and qnrVC were 1.67% and 25%.Adding N-methyl-2-pyrrolidone,Reserpine,Carbonyl cyanide m-chlorophenylhydrazone,Phe-Arg-?-naphthylamide,to the minimum inhibitory concentration of phenicols and quinolone were studied by means of Agar methord for detectiong the changes of MICs.Some strains showed positive results of efflux pump.After added 40?g/mL Reserpine,there were 25 strains of Chloramphenicol,24 strains of Enrofloxacin,4 strains of Norfloxacin and 13 strains of Ciprofloxacin were declined.After added 100?g/mLPA?N or NMP,there are 16 efflux positive strains of chloramphenicol,2 efflux positive strains of florfenicol,6 and 22 efflux positive strains of Enrofloxacin,14 and 17 efflux positive strains of Ciprofloxacin,3 and 6 efflux positive strains of Norfloxacin.After added 5?g/mL CCCP,82 strains of Chloramphenicol,,76 strains of Florfenicol,30 strains of Enrofloxacin,8 strains of Norfloxacin and 5 strains of Ciprofloxacin were declined.Significantly higher than other efflux pump inhibitors.therefore,CCCP can be tested as an effective efflux pump inhibitor for the treatment of phenicols and quinolone.