零售生鲜整鸡中沙门氏菌分离与耐药性分析

Isolation and Antimcirobial Resistance of Salmonella Enterica from Retail Chicken Carcasses

零售鸡肉是沙门菌从养殖场向社区人群传播的重要媒介,对零售鸡肉中沙门菌进行检测、血清分型和药敏分析,可为评估我国社区零售环节整鸡中沙门污染危害提供重要依据。作者2010年8月--2012年3月间,从北京市9个城区共计采集新鲜整鸡样品395个,用美国农业部推荐的整鸡中沙门菌检测方法对所采集样品进行沙门菌分离和鉴定,对分离、纯化的菌株进行PCR确认和血清分型,并测定沙门菌菌株对10种抗生素的最低抑菌浓度。从197（197/395,49.9%）个整鸡样品中检出沙门菌,共计分离沙门菌874株。主要血清型为肠炎（n=309株,来自94个样品）、印第安纳（n=205株,来自54个样品）和婴儿沙门菌（n=89株,来自23个样品）,从农贸市场采集的整鸡样品中,沙门菌检出率显著高于超市采集的样品（P〈0.01）。在不同血清型间,沙门菌的耐药谱存在明显差异。从100个整鸡样品中检出多重耐药沙门菌,102株沙门菌分离株（分离自41个样品）对临床门诊治疗沙门菌感染的首选经验用药环丙沙星和三代头孢类抗生素同时耐药,99株为印第安纳血清型。本研究显示,社区零售整鸡中沙门菌污染率较高,是耐药沙门菌的重要储存库和感染来源,应引起卫生和食药部门的足够重视,研究结果为评估我国社区零售环节生鸡肉中沙门菌对社区居民造成的风险和控制措施制定提供了基础数据。

Retail chicken are primary vehicles of Salmonella transmission from chicken raising farms to human beings in the com- munity. Detecting Salmonella contamination in retail chicken samples and analyzing the serotypes and antimicrobial susceptibility can provide baseline data for the risk assessment and evaluation of new control measures of Salmonella contamination. Whole chicken car- casses （ n = 395 ） were collected from 39 retail markets of nine districts in Beijing from August 2010 to March 2012 and Salmonella isolates were recovered by using USDAZFSIS recommended method. Presumptive Salmonella isolates were identified by PCR method. Confirmed Salmonlla isolates were further characterized by serotyping and antimierobial susceptibility test to 10 antimierobials via agar microdilution method, including ampieillin （ AMP）, ampicillin-sulbactam （ AMS ）, ceftazidime （ CAZ ）, eefotaxime （ CTX ） , chloramphenicol （CHL） , ciprofloxacin （ CIP ） , gentamicin （ GEN ） , imipenem （ IMP ）, nalidixie acid （ NAL ） and tetracycline （TET）. Overall,49.9% （197/395） of the retail whole chicken carcasses were contaminated by Salmonella and 874 Salmonella isolates were recovered. The dominant serotypes were Enteritidis （ n = 309 isolates, from 94 samples）, Indiana （ n = 205 isolates, from 54 samples） and Infantis （n = 89 isolates, from 23 samples）. Chicken carcasses from farmer＇s market showed significantly higher Salmonella recovery rate than those from supermarket （ P 〈 0.01 ）. Different antimicrobial resistance profiles were observed among different Salmonella serotypes. Multi-drug resistant Salmonella isolates were recovered from 100 chicken carcasses and 102 isolates （from 41 samples） were resistant to ciprofloxaein and third-generation cephalosporins which were the first rank antimierobials of salmonellosis treatment for outpatients, and 99 isolates were S. Indiana. The most common antimicrobial resistance profiles were NAL （ n = 124）, AMP-AMS-NAL （ n = 118 ）, AMP-AMS-CHL-CIP-CTX-GEN-NAL-TET （ n = 52 ）, AMP-NAL （ n = 38 ） and TET （ n = 34 ）. Nine S. Indiana isolates （ from 5 samples） recovered through RV broth showed resistance to nine antimicrobials ： CAZ-CTX-CIP- NAL-AMP-SAM-CHL-GEN-TET. Our findings showed a high prevalence of Salmonella contamination in retail chicken carcasses which could be a main source of exposure for consumers to muhidrug resistant isolates. This study provided baseline data for the risk assessment and evaluation of new control measures of Salmonella contamination in retail chicken products.