Analysis Of Drug Resistance And MLST Of Salmonella From Animals In Xinjiang

Salmonella is an important foodborne pathogens that can be transmitted directly or indirectly through the digestive tract,they are easily associated with other diseases,it can cause seriously economic losses to the aquaculture industry.In order to understand the resistance of Salmonella in Xinjiang to the commonly used antimicrobial agents,and grasp the carrying of drug resistance genes and analyze the genetic relationship between resistant strains.In this study,fecal samples of swine 200,sheep 101 and bovine 200were collected and the Salmonella was isolated and the minimum inhibitory concentration was determined by agar dilution method.The results showed that:?1?131 strains Salmonella isolated from swine had the highest resistance rate to ciprofloxacin and apramycin,which were 77.9%?102/131?.The resistant bacteria were mainly to 8-resistant?29.0%,38/131?.?2?52 strains Salmonella isolated from sheep had the highest resistance rate to florfenicol?92.3%,48/52?and tetracycline?90.4%,47/52?,and the resistant bacteria were mainly to 7-resistant?26/52,50.0%?.?3?30 strains Salmonella isolated from bovine were mainly resistant to florfenicol?43.3%,13/30?,and mainly to 1-resistant and 0-resistant.The mainly?-lactamase genes(include bla _TEM,bla_CMY-2,bla_CTX-M,bla_LAP-1,bla_KPC,bla _OXA and bla_SHVHV genes),16S rRNA methylation enzymes?include armA and rmtB genes?and PMQR determinants?include qnrA,qnrB,qnrC,qnrD,qnrS,qepA,oqxA,oqxB and aac?6'?-Ib genes?were detected by PCR.The result showed:?1?11 kinds of resistance genes were detected from resistant Salmonella from swine.There were24 different types of gene combinations,mainly bla_TEM+bla _OXA+qnrS+aac?6??-Ib-cr+oqxA+oqxB?27.2%,31/116?,bla_TEM+bla_OXA+qnrS+oqxA+oqxB?23.2%,27/131?and bla_TEM+qnrS?16.4%,19/116?.?2?6 kinds of resistance genes were detected from resistant Salmonella from sheep.There were 8 different types of gene combinations,mainly bla_TEM+bla_OXA+qnrS+aac?6'?-Ib+oqxA+oqxB?51.0%,24/47?,bla_TEM+bla_OXA+qnrS+aac?6'?-Ib-cr+oqxA+oqxB?14.9%,7/47?.?3?4 kinds of resistance genes were detected from sensitive Salmonella from bovine.There were 4 different types of gene combinations,mainly bla_TEM+oqxB?49.9%,3/6?.7 strains carrying multidrug resistance genes from swine and sheep were selected,and were carried out typing by MLSA.The thrA?purE?sucA?hisD?aroC?hemD and dnaN 7 housekeeper genes were amplified by PCR,and the products of PCR were sequenced and analyzed.The results showed that:the ST34 was the mainly type in Salmonella from swine and sheep,and a new ST-type was found.By the evolutionary tree to analyze the genetic relationship,there was a clonal propagation resistance mechanism between Salmonella from swine and sheep in this study.Salmonella from animal in Xinjiang showed different degrees of resistance to the antimicrobial agents,and the degree of resistance was in the order of swine source>sheep source>bovine source bacteria,and the resistance patterns of different animal sources were different.The coexistence of?-lactamase and PMQR factors in the different animal source bacteria suggests that the phenomenon of multiple resistance is complex and diverse,and the presence of multiple drug-resistant genes at the same time makes the risk of becoming a super-resistant bacteria.MLST results suggest that there are clonal propagation mechanisms in swine and sheep resistant Salmonella,and the number of resistant strains may increase significantly in recently.