Isolation and Identification of Chicken-derived Salmonella Senftenberg and Detection of Drug Resistance and Virulence Genes
[Objective]This study was aimed to determine the pathogen and drug sensitivity of a suspected Salmonella infection in a broiler farm in Guangdong province,and provide scientific basis for formulating effective prevention and control and purification measures and rational antibiotic using program.[Method]In this study,Salmonella isolation and culture,Gram staining,biochemical test,invA-specific gene PCR identification,16S rRNA identification and serotyping were performed on liver and intestinal samples of several sick chickens from a large-scale chicken farm in Guangdong province.K-B drug sensitivity method was used to detect the sensitivity of the strains to 20 kinds of antibiotics.The drug resistance genes and virulence genes were detected by PCR.[Result]In isolation and culture,it could be seen that colorless transparent,small dewdrop-like colonies or smooth,round,transparent and moist colonies with black center could be found.The suspected colonies were pink in Gram staining,scattered in distribution and slightly round at both ends,no capsule,no spore.The biochemical test showed gas production,acid production at the bottom,hydrogen sulfide production was black,and alkali production on the inclined surface turned red.PCR was performed to amplify the suspected colonies DNA,and the invA specific gene amplified a band of about 285 bp,and the 16S rRNA amplified a band of about 1 500 bp.In this study,a total of 8 strains of Salmonella Senftenberg were isolated and identified.The results of drug susceptibility test showed that 8 strains had no resistance to ceftazidime,gentamicin,amikacin,kanamycin,minocycline,doxycycline and polymyxins B.However,the resistance rates to penicillin,cephalexin,vancomycin,erythromycin,lincomycin,ampicillin,piperacillin,cefazolin,cefuroxime sodium,ceftriaxone,cefoperazone,streptomycin and tetracycline were high,ranging from 87.5％to 100％,and the isolates were all multi-drug resistant bacteria,qnrS and stcM resistance genes were detected in 7 strains,and no resistance genes were detected in 1 strain.The test results of virulence genes showed that detection rates of invA,hilA,sipA,sipC,ssrA and stnP1 genes were 100％,and sopB and ssaR genes were 50.0％and 62.5％,respectively.[Conclusion]All isolates of chicken-derived Salmonella Senftenberg had multi-drug resistance and were sensitive to 7 species drugs,including ceftazidme and amicarcin,but the carrying rates of six virulence genes invA,hilA,sipA,sipC,ssrA and stnP1 were 100％.The results of this study supplemented the epidemiological data of Salmonella of chicken origin and provided theoretical reference for the prevention and control and purification of clinical Salmonella.
Salmonella Senftenbergisolation and identificationdrug resistancevirulence gene
万方数据
维普
