进口鸡翼中单核细胞增生李斯特菌的鉴定及其 挥发性产物分析

Identification of Listeria monocytogenes from imported chicken wings and analysis of its volatile compounds

中文关键词:  单核细胞增生李斯特菌  鉴定  挥发性产物  顶空气相色谱-质谱联用法

英文关键词:Listeria monocytogenes  identification  volatile compounds  headspace gas chromatography-mass spectrometry

中文摘要:

      目的 对从进口鸡翼中分离的菌株F7-10进行种属鉴定, 并通过顶空气相色谱-质谱联用法(headspace gas chromatography-mass spectrometry, HS-GC-MS)分析其液态培养代谢的挥发性产物。方法 通过VITEK 2 Compact全自动微生物鉴定系统分析菌株的生理生化特征, 结合16S rRNA基因和prfA基因PCR扩增测序鉴定分离菌株, 通过HS-GC-MS分析分离菌株F7-10代谢的挥发性产物, 并与单核细胞增生李斯特菌ATCC 13932、格氏李斯特菌ATCC 700545和英诺克李斯特菌ATCC 33090的代谢挥发性产物进行比较分析。结果 菌株F7-10为革兰氏阳性菌, 生理生化特征与单核细胞增生李斯特菌(Listeria monocytogenes)的相似性为98%, 协同溶血实验在靠近金黄色葡萄球菌的接种端溶血增强; 16S rRNA基因序列与单增李斯特菌标准菌株的相似性为99%, prfA基因特异性扩增出现预期大小的目的片段。菌株F7-10在营养肉汤中代谢的挥发性产物主要有乙醇、3-羟基-2-丁酮、乙酸、丁酸、3-甲基戊酸、十二醇等, 与单增李斯特菌标准菌株的代谢挥发性产物种类相似, 但含量有差别。结论 进口鸡翼中分离的菌株F7-10鉴定为单核细胞增生李斯特菌, 该菌产生的挥发性产物可为单核细胞增生李斯特菌的鉴定提供参考。

英文摘要:

      Objective To identify and characterize a bacterial strain F7-10 isolated from the imported chicken wings and analyze its volatile compounds (VCs) of liquid-state fermentation by headspace gas chromatography-mass spectrometry (HS-GC-MS). Methods The physiological and biochemical characteristics of the strain were elucidated by using VITEK 2 compact automated microbiology system. The 16S rRNA gene was sequenced and prfA gene from F7-10 was amplified by PCR to detect strain F7-10. Volatile compounds from F7-10 cultured with nutrient broth were detected by HS-GC-MS. The VCs emitted from four strains, including Listeria monocytogenes ATCC 13932, Listeria grayi ATCC 70054, Listeria innocua ATCC33090 and F7-10, were analyzed and compared. Results Strain F7-10 was identified as gram-positive bacteria and exhibited the highest levels of 98% probability to be Listeria monocytogenes based on the conventional physiological test. An enhanced zone of β-haemolysis at the intersection of Staphyloccocus aureus was found. The sequence analysis of 16S rRNA gene of F7-10 isolation showed that it was very close to Listeria monocytogenes and the similarity was 99%. The purposed gene fragment was detected based on prfA gene amplification. The main VCs produced by F7-10 in nutrient broth were detected to be ethanol, acetoin, acetic acid, butanoic acid, 3-methylvaleric acid and dodecyl alcohol. The varieties of VCs behaved similarly between F7-10 and Listeria monocytogenes standard strain, but the content behaved differently. Conclusion Bacterial strain F7-10 isolated from the imported chicken wings is identified as Listeria monocytogenes. The VCs produced by F7-10 can provide basis for the identification of Listeria monocytogenes.