Drug Resistance Detection And Integrons Analysis Of Vibrios From Mariculture Source

Vibrio is a genus of Gram-negative bacteria possessing a curved rod shape, whichhas polar flagellum and do not form spores, and which is very common in the marineenvironment widely distributed. Vibrios are designated as conditional pathogens, whenthe water quality condition and reservoir condition changes, especially easy to causelarge-scale outbreak of vibriosis, and Vibrio vulnificus, Vibrio parahaemolyticus, Vibriodamsel, etc. are zoonotic pathogen, so in order to clear the situation and structurecomposition of Vibrios from mariculture source in different provinces and differentanimals, In this study,106Vibrio strains were isolated from sick animals andaquaculture water in Chinese districts including Jiangsu, Zhejiang, Fujian and Hainanprovince. They were identified by TCBS specific medium combined with biochemicalidentification and molecular methods. These Vibrios were composed of33V.parahaemolyticus,33V. harveyi,15V. alginolyticus,9V. anguillarum,4V. vulnificus,3V. cyclitrophicus,3V. cholera,2V. brilliant,2V. Chavez,1V. mimicus,1V. furniss.In order to detect drug resistance of106strains of Vibrios,reflect the current use ofantibacterials in aquaculture, provide certain theoretical science basis for theaquaculture drugs in the future. In this study, inhibition zone of106strains of vibriowere detect by8categories contain14kinds of antibacterials, The results showed thatstreptomycin and kanamycin is the most serious drug resistance, novobiocin is moresevere antibacterial resistance, norfloxacin, florfeniol, chloramphenicol and ceftriaxoneare sensitive rate higher antimicrobial drugs,97.17%,94.34%,93.40%and92.45%respectively; antibiogram type analysis showed that, multiple drug resistant strainsresistant to3kinds of antibacterials or more have42strains accounted for49.1%,S/K/NV appear most in3resistance (strains which resistant to3antibacterials),accounting for72.22%of the total resistance of3, two stranis of Vibrio in4resistancehanve the same type which is S/NV/RD/K, accounting for16.67%, S/TE/SXT/RD/DOin5resistance account for50%, one7resistance type is S/C/TE/NV/RD/DO/K, twostrains of Vibrio in8resistance are E/S/C/TE/SXT/NV/RD/K andCIP/CRO/S/TE/SXT/NV/RD/FFC. Second select eight kinds of antibacterials, the brothdilution method were used to detect the106strains of vibrio minimum inhibitoryconcentration (MIC), and the results of the two methods are compared. The results showed that, streptomycin has the highest average MIC including80.12g/ml, the rest ofthe order from large to small is erythromycin including26.47g/ml, chloramphenicolincluding8.16g/ml, and cotrimoxazole5.89/29.47including g/ml, ceftriaxoneincluding2.73g/ml, norfloxacin including0.94g/ml, fluorine benzene nicol, including0.92g/ml, rifampicin including0.48g/ml. Finally in the two methods of correlationanalysis, found the bacteriostatic circle diameter and MIC negatively correlated with theoverall (excluding individual strains of individual drugs), that is, the test results of twomethods is consistent.In order to analysis of106strains of mariculture source vibrio integron-gene box.In this syudy,using ordinary PCR technique, class I,II, III integrase gene in5’-CS and3’-CS gene of all isolates were amplified. The results showed that, class1integrasepositive rate was89.62%(95/106), class2integrase positive rate was0%(0/106),class3integrase positive rate is0%(0/106); class I integron3’end amplificationshowed that the positive rate of qacE Δ1is10.38%(11/106) and the positive rate ofsul1is11.32%(12/106).Then, when for the amplification of eight strains which showpositive results in5’-CS and3’-CS,this study found that the three strains of vibriocarried two gene cassette: a V. alginolyticus239carrying arr-3-dffrA27gene cassette, aV. cyclitrophicus295carrying arr-3-dffrA27gene cassette, a V. cyclitrophicus291carrying dfr16-aadA2gene cassette. Finally, this study chose two two kinds ofdisinfectant which are TCCA and BB,Studing on the minimum inhibitory concentration(MIC)of106vibrio isolates,Found that both MIC were as high as disinfectants498.00mg/L and320mg/L, respectively, meaning that the strains also produced a certaindegree of resistance to disinfectants.Summary, mariculture sources Vibrio Separated in four provinces produce drugresistance to different types of antibacterials and disinfectants. Especially mobile geneintegron–gene cassette system exists has a huge influence on the horizontal andvertical spread of drug resistant. This phenomenon inspired us, in practice aquacultureproduction, Vibrio resistance needed to detect timing and stop,making the drugresistance of Vibrio is in a state of security. avoiding the economic losses from thevibriosis, Providing theoretical guidance for the development of aquaculture, and thescientific basis for the research of the drug resistance of vibrio.