成都市部分宠物诊疗和交易市场环境中大肠埃希菌及肠球菌对常用抗生素的耐药特征分析

Antibiotic resistance profiles of Escherichia coli and Enterococcus spp.originated from pet clinics and trading markets in Chengdu City

为了解成都市区宠物诊疗和交易市场环境中大肠埃希菌和肠球菌的耐药现状,从15个宠物公共活动场所中采集了433份样本(98份空气样本和335份各类物体表面样本),通过细菌分离培养、鉴别纯化和16S rRNA基因测序,成功鉴定出大肠埃希菌174株(174/433,40.18%)和肠球菌288株(288/433,66.51%),且在清洁程度较差的环境中可分离出更多的目标细菌.耐药特征分析结果显示,有163株大肠和288株肠球菌分别对常用的β-内酰胺、四环素和氟喹诺酮类抗生素产生耐药.耐药的大肠埃希菌中双重耐药的菌株数量占比最多(41.95%,73/174),并且有65株为多重耐药菌(7.35%,65/174),以头孢噻肟-多西环素-恩诺沙星为主要耐药表型(44.62%,29/65),耐药肠球菌以多西环素-恩诺沙星双重耐药为主要表型(38.54%,111/288),并且有56株为多重耐药菌(19.44%,55/288),其中,以氨苄西林-阿莫西林-克拉维酸钾-多西环素-恩诺沙星为主要耐药表型(94.64%,53/56).上述耐药菌多数分离自宠物诊疗环境,并且显示出耐药表型的多样性.多重耐药大肠埃希菌携带的优势耐药基因为tetA(92.31%,60/65)、tetB(100%,65/65)、blaTEM(75.38%,49/65)和blaCTX-M(70.76%,46/65),而多重耐药肠球菌携带的优势耐药基因为blaTEM(41.82%,23/55).总之,研究结果明确了当地不同宠物活动环境中细菌耐药的流行现状,分析其对宠物常用抗生素的耐药性和携带优势耐药基因的特征,揭示了目前存在的细菌耐药性传播和在人-宠物群体间扩散的风险,为后续环境细菌耐药性形成的研究和监控措施的制定提供了思路,具有现实的公共卫生学意义.

To investigate the antibiotic resistance status of Escherichia coli and Enterococcus spp.in the pet clinic and trading market environments in Chengdu City,this study collected 433 samples(98 air samples and 335 surface samples from various objects)from 15 pet public activity sites and identified 174 E.coli strains and 288 Enterococci strains by bacterial culture,dif-ferentiation,and 16S rRNA gene sequencing.The results showed that more target bacteria could be isolated from environments with poor cleaning conditions.The antibiotic resistance feature analysis showed that 163 E.coli strains and 288 Enterococci strains were resistant to beta-lactam,tetracycline,and fluoroquinolone antibiotics,respectively.Among the resistant Escherichia coli strains,the proportion of double resistant strains was the highest(41.95%,73/174),and 65 strains were multi-resistant(7.35%,65/174),with cefotaxime-doxycycline-enrofloxacin as the main resistant phenotype(44.62%,29/65).The main phenotype of resistant Enterococcus was the dual resistance to doxycycline and enrofloxacin(38.54%,111/288),and strains were multi-resistant bacteria(19.44%,55/288),among which ampicillin-amoxicillin/clavulanate-doxycycline-enroflox-acin was the representative resistance phenotype(94.64%,53/56).The majority of the resistant bacteria were isolated from the environments of pet clinics,and showed diversity in the antibiotic-resistant phenotypes.The dominant resistance genes carried by multi-drug resistant E.coli were tetA(92.31%,60/65),tetB(100%,65/65),blaTEM(75.38%,49/65),and blaCTX-M(70.76%,46/65),while the dominant resistance gene carried by multi-drug resistant Enterococci was blaTEM(41.82%,23/55).In summary,the results of this study clearly indicated the prevalence of bacterial resistance to commonly used antibiotics o-riginated from different pet activity environments in Chegndu City,which carried abundant resistance genes,revealing the risks of antibiotic resistance transmission and spread between human-pet populations,and providing perspectives for future research on the formation of environmental bacterial resistance and monitoring measures of public health significance.