市售散装白斩鸡表面四环素耐药菌污染初探  

Prevalence and Characteristics of Tetracycline-Resistant Bacteria in Bulk Soft-Boiled Chicken

作　　者：李会贤 冯博 黄柳娟 邵毅[1] 张东来[1] LI Huixian;FENG Bo;HUANG Liujuan;SHAO Yi;ZHANG Donglai(Institute for Agri-food Standards and Testing Technology,Shanghai Academy of Agricultural Sciences,Shanghai 201403;College of Food Sciences and Technology,Shanghai Ocean University,Shanghai 201306)

机构地区：[1]上海市农业科学院农产品质量标准与检测技术研究所,上海201403 [2]上海海洋大学食品学院,上海201306

出　　处：《核农学报》2022年第1期129-135,共7页Journal of Nuclear Agricultural Sciences

基　　金：上海市科技兴农重点攻关项目(应用基础类)[沪农科攻字(2014)第7-3-6号];国家自然科学基金青年科学基金项目(31401599);上海农产品质量安全工程技术研究中心(19DZ2284100)。

摘　　要：为探究市售散装白斩鸡表面四环素耐药菌的污染特征,评价耐药基因的迁移潜势,本试验从上海市4个区的25个熟食店中采集25份散装即食白斩鸡样品,采用梯度稀释法和脑心浸液肉汤培养基对四环素耐药菌(TET^(r))进行计数,利用实时荧光定量PCR(qRT-PCR)技术分析6种四环素耐药基因(tet A、tet B、tet C、tet D、tet J、tet M)和一类整合酶基因intⅠ的相对拷贝数,并对13株TET^(r)菌株进行种属鉴定和多重耐药性分析,最后通过自然转化探究其耐药性的水平迁移可能性。结果表明,所有样品均分离到TET^(r)菌,菌落数为(7.07×10^(1)~1.67×10^(8))CFU·g^(-1),占总可培养细菌总数的1.01%~100%;13个样品中6种tet基因和intⅠ基因的相对拷贝数为10^(-4)~10^(-2);分离到的TET^(r)菌主要有芽孢杆菌(Bacillus)、莫拉氏菌(Moraxella)、气单胞菌(Aeromonas)等,所有菌株均至少对2种抗生素耐药,其中2株莫拉氏菌和1株不动杆菌(Acinetobacter)可将四环素耐药表型迁移至大肠杆菌J53中,接合频率为10^(-6)或10^(-2)。综上,市售散装白斩鸡表面存在四环素耐药菌污染,且耐药基因具有水平迁移至异种细菌的风险。本研究为市售散装白斩鸡产品中的抗生素耐药菌监测及风险评估提供了方法参考和数据支撑。In order to describe the contamination characteristics of tetracycline-resistant(TET^(r))bacteria on the surface of commercially available bulk soft-boiled(BSB)chickens,and to evaluate the migration potential of antibiotic-resistance(AR)genes,25 samples of ready-to-eat BSB chicken were collected from 25 delis in 4 Districts of Shanghai.Then TET^(r) bacteria were counted by serial dilution method,and six tetracycline resistance genes,included tet A,tet B,tet C,tet D,tet J and tet M,as well as an integrase gene intⅠwere quantitatively analyzed by Quantitative real-time PCR(qRT-PCR).At last,the genus,multi-drug resistance,and the potential horizontal transmission of AR genes of 13 TET^(r) isolates were analyzed by 16S rDNA identification,disk diffusion and natural transformation respectively.The results showed that,TET^(r) bacteria were detected in all the chicken samples with levels of(7.07×10^(1)~1.67×10^(8))CFU·g^(-1),which accounted for 1.01%to 100%of the total numbers of cultivable bacteria.Meanwhile,the relative copy numbers of tet and intⅠgenes ranged from 10^(-4) to 10^(-2).Furthermore,13 TET^(r) isolates collected from the chicken samples,included four Bacillus,three Moraxella,two Aeromonas,one Streptococcus pneumonia;one Acinetobacter,one Lactococcus lactis subsp.and one Shewanella,were all resistant to at least two antibiotics.At last,TET^(r) phenotype was migrated from two strains of Moraxella and one strain of Acinetobacter to E.coli J53 with the conjugative transformation frequencies of 10^(-6),10^(-2) and 10^(-2) respectively.In conclusion,there is potential high level of TET^(r) bacteria contamination on the surface of commercially available ready-to-eat BSB chicken,and the risk of horizontal migration of AR genes to heterogeneous bacteria is existed.This study provides method reference and data support for monitoring and risk assessment of antibiotic resistant bacteria in soft-boiled chicken products.

关 键 词：白斩鸡 四环素耐药菌 四环素耐药基因 迁移风险 

分 类 号：TS251.6[轻工技术与工程—农产品加工及贮藏工程]