摘要
为了调查湖南浏阳地区某生猪养殖场屎肠球菌的耐药情况及耐药基因可能存在的传播机制,从浏阳地区某猪场中采集不同生长阶段猪只肛拭子以及环境样本共345份,从中分离鉴定出76株肠球菌,其中屎肠球菌1株(1.3%),采用琼脂扩散法考察屎肠球菌对10种抗菌药物的耐药情况,并对该菌株进行全基因组测序,检测其耐药基因和毒力基因的分布情况,最后对optrA特定基因组结构进行分析。结果显示,从猪只肛拭子样本分离的编号Ec63菌株,经全基因组测序组装、拼接,得到一条大小为2759403 bp的环状DNA(GC含量为37.9%),携带9大类抗菌药的10种耐药基因,均定位于染色体上,其中氨基糖苷类耐药基因数量最多,且携带有噁唑烷酮类耐药基因optrA;此外,该菌株携带sagA等毒力基因21个,不含有强毒菌株的毒力基因序列。药物敏感性试验结果表明,该菌株对头孢噻呋、四环素呈现高度耐药,对恩诺沙星、万古霉素、红霉素、庆大霉素、头孢西丁、氟苯尼考、利奈唑胺和甲氧苄啶/磺胺甲噁唑敏感。特定基因组结构分析显示,该菌株存在fexA-optrA核心遗传环境。结果表明,该菌株对机体表现弱毒力的潜力,但存在多耐药性(MDR)基因,是一株多重耐药屎肠球菌。fexA-optrA的基因遗传环境在屎肠球菌耐药传播中起着重要作用,对公共卫生安全具有潜在威胁。本研究结果可为屎肠球菌在养殖业中的应用提供参考依据。
In order to investigate the drug resistance of Enterococcus faecalis in a pig farm in Liuyang,Hunan Province,and the possible transmission mechanism of drug resistance genes,a total of 345 anal swabs and environmental samples were collected from pigs at different growth stages in a pig farm in Liuyang,Hunan Province,and 76 strains of enterococci were isolated and identified from them,among which one strain of Enterococcus faecalis(1.3%)was detected,and the resistance to 10 antimicrobial drugs was determined by agar diffusion method.Whole genome sequencing was performed to detect the distribution of resistance genes and virulence genes of this strain,and finally the structure of the specific genome where optrA was located was analyzed.The results showed that the numbered Ec63 bacteria isolated from pig anal swab samples were assembled and spliced by whole-genome sequencing to obtain a circular DNA with a size of 2759403 bp(GC content of 37.9%),carrying a total of 10 resistance genes for 9 major classes of antibiotics,all of which were localized on the chromosome,with the largest number of aminoglycoside resistance genes,and notably,the oxazolidinone resistance gene,optrA.In addition,21 virulence genes such as sagA were carried,which did not contain the virulence gene sequences of strong virulent strains.The results of drug susceptibility tests showed that the strain presented high resistance to ceftiofur and tetracycline,and sensitivity to enrofloxacin,vancomycin,erythromycin,macromycin,cefoxitin,fosfenicol,linezolid,and methotrexate/sulfamethoxazole.Specific genomic structure analysis revealed the presence of a fexA-optrA core genetic environment.The results showed that this strain has the potential to exhibit weak virulence to the organism,but the presence of multi-drug resistance(MDR)genes makes it a multi-drug resistant Enterococcus faecalis strain.The fexA-optrA genetic environment plays an important role in the transmission of Enterococcus faecalis drug resistance and remains a potential threat to public health safety.The results of this study provide a reference for the use of Enterococcus faecalis in aquaculture.
作者
郑姣妹
黄培宏
李妍芬
邓钰
李振伟
陈小军
王洪亮
ZHENG Jiaomei;HUANG Peihong;LI Yanfen;DENG Yu;LI Zhenwei;CHEN Xiaojun;WANG Hongliang(Changsha Center for Animal and Plant Disease Prevention and Control,Changsha Hunan 410013,China;College of Veterinary Medicine,Hunan Agricultural University,Changsha Hunan 410125,China)
出处
《中兽医医药杂志》
CAS
2024年第5期27-31,共5页
Journal of Traditional Chinese Veterinary Medicine
基金
湖南省教育厅资助科研项目(22B0189)
长沙市动植物疫病预防控制中心资助项目(0123017)。
关键词
屎肠球菌
分离鉴定
全基因组测序
optrA
Enterococcus faecalis
isolation and identification
whole genome sequencing
optrA
作者简介
郑姣妹(1973-),女,高级兽医师,研究方向为预防兽医学,同等贡献作者。Email:330127528@qq.com;黄培宏(1999-),男,硕士研究生在读,研究方向为细菌耐药性,同等贡献作者。Email:826286889@qq.com;通信作者:陈小军(1972-),女,教授,博士,研究方向为基础兽医学。Email:308630837@qq.com;通信作者:王洪亮(1987-),男,高级兽医师,研究方向为预防兽医学。Email:10777329@qq.com。
