胶东地区不同家禽弯曲菌流行分布及耐药特征分析

Prevalence and antimicrobial resistance of Campylobacter from poultry in the Jiaodong area

目的通过了解胶东地区不同禽源弯曲菌的耐药现状及分子流行分布情况,为有效防控禽源弯曲菌对家禽产品和人类健康带来的风险提供依据。方法采用细菌常规分离培养、质谱鉴定、微量肉汤稀释法和多位点序列分型(Multilocus Sequence Typing,MLST)技术,对2021年8月至10月期间,在胶东地区采集的565份泄殖腔样品进行弯曲菌分离鉴定,并别对131株代表性菌株(67株空肠弯曲菌、64株结肠弯曲菌)进行了耐药性及分子分型研究。结果分离菌株对环丙沙星、萘啶酸、四环素显示出高水平耐药,耐药率分别为96.18%、96.18%、94.66%,除2株结肠弯曲菌外,其余62株结肠弯曲菌对这3种药物均为完全耐药(100%);131株菌株中共65株多重耐药,总体多重耐药率为49.62%,其中11株空肠弯曲菌(16.42%)分布在3~5耐,54株结肠弯曲菌(84.38%)分布在3~6耐;在不同禽源分离菌株中,水禽分离菌株耐药程度最严重,其次是肉鸡。MLST分型结果表明,67株空肠弯曲菌共得到72个等位基因、35个序列型,分布较分散,无优势ST型和同源复合体;64株结肠弯曲菌共得到27个等位基因、19个序列型,59.38%(38/64)的菌株为同源复合体CC-828,其中ST-1586序列型最多,其次是ST-825;肉鸡源结肠弯曲菌主要以ST-1586、ST-9944、ST-3735为主,水禽以ST-825、ST-1586居多。结论胶东地区不同家禽中空肠弯曲菌和结肠弯曲菌的携带存在差异,蛋鸡携带两种菌的现象较肉鸡、水禽较为普遍;胶东地区禽源空肠弯曲菌对环丙沙星、萘啶酸、四环素耐药严重,对其它药物敏感性好,结肠弯曲菌对多种抗菌药物耐药严重,且多重耐药普遍;空肠弯曲菌ST型分散,该菌具有较高的遗传多样性,结肠弯曲菌在肉鸡和水禽以ST-1586为主的克隆传播;家禽携带能引起人类严重疾病的空肠弯曲菌,应加强禽源弯曲菌的动态监测。

This study was aimed to understand the current status of the antimicrobial resistance and molecular distribution of Campylobacter in various poultry in Jiaodong area,to provide a basis for effective prevention and control of the Campylobacter risk to poultry products and human health.Campylobacter was isolated and identified from 565 cloacal samples collected in the Jiaodong area from August to October 2021 through conventional bacterial isolation and culture,mass spectrometry,microbroth dilution and multilocus sequence typing(MLST).The drug resistance and molecular typing of 131 representative strains(67 Campylobacter jejuni and 64 Campylobacter coli)were studied separately.Antimicrobial resistance analysis indicated that 131 isolates were highly resistant to ciprofloxacin,nalixic acid and tetracycline,with resistance rates of 96.21%,96.21%and 95.45%,respectively.Except for 2 strains,62 strains of C.coli were completely resistant to these three drugs(100%).A total of 65 strains of 131 strains were multidrug resistant,and the overall multidrug resistance rate was 49.62%,among which 11 strains(16.42%)of C.jejuni were resistance to 3-5 antibiotics,and 54 strains(84.38%)of C.coli were resistance to 3-6 antibiotics.Among the isolates from different poultry sources,waterfowl isolates were the most resistant,followed by broiler isolates.The MLST typing results revealed 72 alleles and 35 sequence types obtained from 67 strains of C.jejuni,and the distribution was relatively dispersed,without a dominant ST type and homologous complex.A total of 27 alleles and 19 sequence types were obtained from 64 strains of C.coli.Moreover,59.38%(38/64)strains were homologous complex CC-828,in which the ST-1586 sequence type was most frequent,followed by ST-825.ST-1586,ST-9944 and ST-3735 were the main sources of C.coli in broilers,and ST-825 and ST-1586 were the main sources of C.coli in waterfowl.Differences in C.jejuni and C.coli carriage were observed among poultry in the Jiaodong area.Carriage of the two bacteria was more common in laying hens than in broilers and waterfowl.C.jejuni from poultry in the Jiaodong area was highly resistant to ciprofloxacin,nalixic acid and tetracycline,but had good sensitivity to other drugs.C.coli was highly resistant to a variety of antibiotics,and multiple drug resistance was common.St-type dispersal of C.jejuni showed high genetic diversity.C.coli was cloned and transmitted mainly by ST-1586 in broiler chickens and waterfowl.Poultry carry C.jejuni,which can cause serious diseases in humans.Therefore,dynamic monitoring of Campylobacter from poultry should be strengthened.