| In order to understand the antimicrobial resistance and antimicrobial resistance gene carrying situation of Enterococcus from different animals in some regions,Xinjiang,to guide the clinical rational antimicrobial use for different animals,the transmission mechanism in feces and epidemic characteristics of oxazolidinone antimicrobial resistance gene optr A from different animals in Xinjiang.Samples were collected from farms in 9 counties and districts of Xinjiang to isolate and identify Enterococcus.The minimum inhibitory concentrations of 11 kinds of antimicrobials of isolated Enterococcus were determined by agar dilution method recommended by CLSI,and 10 kinds of antimicrobial resistance genes were detected by PCR.The epidemiological characteristics and transmission mechanism of optr A gene mainly in Enterococcus faecalis from animals in Xinjiang were investigated by MLST and PFGE molecular typing,conjugation transfer test and whole genome sequencing.A total of 599 Enterococcus strains were isolated from 771 fecal samples collected from pigs,cattle,sheep,camels,horses,chickens and pigeons in 9 counties and districts of Xinjiang,among which E.faecalis(350 strains)was the largest,accounting for 58.4% of all Enterococcus.The distribution of Enterococcus species in different animals was different.Enterococcus isolates had high antimicrobial resistance rates to gentamicin,tetracycline,erythromycin,doxycycline and rifampicin,so the use of these five antimicrobials should be reduced in the breeding process.Enrofloxacin,flufenicol,ampicillin and other highly sensitive antimicrobials should be selected according to the antimicrobial sensitivity results to improve the efficacy.The detection rate of aac(6’)/aph(2")gene was the highest(84.5%),and the detection rate of tet M,aph(3’)-Ⅲ and erm(B)gene was also more than 60.0%.It was consistent with the antimicrobial susceptibility test results.Attention should be paid to the use of tetracycline,macrolides and aminoglycosides.Oxazolidinone antimicrobial resistance gene optr A was detected in all E.faecalis from animals except sheep.After MLST and PFGE molecular typing,the 29 optr A-positive E.faecalis strains detected in this study were divided into 13 ST types(including 3 new alleles)and 20 PFGE bands.The dominant ST-type of a pig farm in Changji were ST714 and ST1168,and the homology of optr A-positive E.faecalis from different animals was not obvious.Thirteen strains of positive E.faecalis were able to transfer optr A gene to JH2-2,and 9 of them were completely sequenced from donor strains that were not of the same clone type.A total of 20 antimicrobial resistance genes were detected.There were many types of antimicrobial resistance genes and the genetic environment was complex,so relevant departments should strengthen supervision and continue to monitor bacterial antimicrobial resistance and antimicrobial resistance gene regularly.Camel-derived E.faecalis F109(a new allele combination ST1171)carried optr A gene on a 74497 bp plasmid,which had high homology with several plasmids reported by human medicine and veterinary medicine at home and abroad.Its horizontal transfer element was IS1216E-optr A-IS1216 E.In conclusion,Enterococcus from different animals in Xinjiang was characterized by high multi-antimicrobial resistance rate,wide antimicrobial resistance spectrum and high gene carrying rate.It is suggested to strengthen the standardized use of antibiotics and rational use of antibiotics for different animals based on the results of antimicrobial sensitivity test.Optr A gene has a high prevalence rate in E.faecalis from animals in Xinjiang,cloning is not the main mode of transmission,and transferable plasmid was an important vector for its epidemic in E.faecalis from animals in Xinjiang.This study preliminarily explored the epidemic and transmission characteristics of optr A gene in animal sources in Xinjiang,and further systematic research should be conducted on the distribution and transmission of other important antimicrobial resistance genes in different Enterococcus from animals. |
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