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目的研究采自产地的鲜活贝类中单核细胞增生李斯特菌(单增李斯特菌)的污染状况、毒力基因分布与耐药性。方法对采自产地的200份鲜活贝类,按照GB/T 4789.30—2010《食品安全国家标准食品卫生微生物学检验单核细胞增生李斯特氏菌检验》进行单增李斯特菌的分离与鉴定;采用Kirby-Bauer纸片扩散法测定分离株的耐药性;通过PCR法分析分离株9个毒力基因(包括prfA、plcB、hly、actA、iap、inlA、plcA、mpl、inlB)。结果在200份鲜活贝类中,共检出阳性样品4份(2.0%);有1株缺失inlB基因,1株缺失mpl基因;分离株对氨苄青霉素、庆大霉素等一线临床治疗药物敏感,但有2株对四环素和复方新诺明同时耐药,1株对复方新诺明和氧氟沙星耐药。结论采自产地的鲜活贝类存在单增李斯特菌的污染,分离株毒力基因有一定程度缺失,提示初级水产品中的单增李斯特菌污染需引起关注,并且需要继续加强食品中该菌的耐药性监测。
Objective To study the contamination status, virulence gene distribution and drug resistance of Listeria monocytogenes (Listeria monocytogenes) in fresh shellfish collected from the producing areas. Methods The isolation and identification of 200 Listeria monocytogenes were carried out on 200 fresh shellfish collected from the producing areas according to GB / T 4789.30-2010 “National Food Safety Standard Microbiological Examination of Listeria monocytogenes” The drug resistance of the isolates was determined by Kirby-Bauer disk diffusion method. Nine virulence genes (including prfA, plcB, hly, actA, iap, inlA, plcA, mpl, inlB) were analyzed by PCR. Results A total of 4 positive samples (2.0%) were detected in 200 fresh shellfish samples. One strain had inlB gene deletion and one strain lacked mpl gene. The isolates were sensitive to ampicillin, gentamicin and other first-line drugs However, two strains were resistant to tetracycline and cotrimoxazole simultaneously. One strain was resistant to cotrimoxazole and ofloxacin. Conclusions Listeria monocytogenes was found in the fresh shellfish collected from the producing areas, and the virulence genes of the isolates were deficient to some extent, which indicated that the contamination of Listeria monocytogenes in the primary aquatic products should be paid more attention and needed to be strengthened The bacteria resistance monitoring.