不同胁迫条件对食品源MRSA菌株生长、毒力和抗性基因表达的影响  

Effects of Stress Conditions on the Growth,Virulence and Resistance Gene Expression of Food-sourced MRSA Strains

作　　者：屈云 贺苏皖 朱成林 赵燕英 陈娟[1,2] 刘骥[1,2] 刀筱芳[1,2] 唐俊妮 Qu Yun;He Suwan;Zhu Chenglin;Zhao Yanying;Chen Juan;Liu Ji;Dao Xiaofang;Tang Junni(College of Food Sciences and Technology,Southwest Minzu University,Chengdu 610041;Key Laboratory of Qinghai-Tibet Plateau Animal Genetic Resource and Utilization,Chengdu 610041)

机构地区：[1]西南民族大学食品科学与技术学院,成都610041 [2]青藏高原动物遗传资源保护与利用教育部重点实验室,成都610041

出　　处：《中国食品学报》2022年第3期8-17,共10页Journal of Chinese Institute Of Food Science and Technology

基　　金：“十三五”国家重点研发计划项目(2018YFD0500500);四川省科技计划项目(2019YJ0261,2019JDJQ0017)。

摘　　要：模拟是研究食品加工过程中亚致死条件对耐甲氧西林金黄色葡萄球菌(MRSA)的影响。选取携带不同背景基因的2株猪肉源MRSA菌株(MRSA6和MRSA18),对其进行常用消毒剂、低温、酸碱及渗透压环境胁迫处理,探究处理前、后菌株生长及毒力和抗性基因表达的变化情况。结果表明,消毒剂新洁尔灭胁迫后菌株携带的毒力及抗性基因表达增加,过氧乙酸对菌株不同抗性基因表达的影响存在差异,而对毒力基因表达有抑制作用,次氯酸钠对菌株携带抗性和毒力基因表达有不同程度的抑制作用;低温、高渗及碱胁迫均抑制菌株相关基因表达;酸胁迫处理除对MRSA 6的mecA表达起到明显促进作用外,对其它抗性基因均呈抑制作用。过氧乙酸对菌株的最小抑菌浓度(MIC)为0.03%,次氯酸钠对菌株的MIC为0.17%,新洁尔灭对菌株的MIC为0.0005%,均低于消毒剂推荐使用浓度。低温胁迫对菌株生长无明显影响,55℃胁迫对菌株生长有较好抑制作用,60℃高温可达到较好杀灭效果。菌株表现出对高渗环境的耐受性,在体积分数35%的氯化钠作用下菌株生长受到抑制。低酸环境(pH 2)对菌株生长有较好抑制效果,碱性环境对菌株生长未有明显影响。通过探究不同胁迫条件对MRSA菌株生长及携带毒力和抗性基因表达的影响,发现食品加工中有些亚致死环境条件会使菌株的毒力和抗性表达增加。本研究结果为食品加工过程中抑菌方法的选择及可能对菌株生长及毒力和抗性的影响提供参考。The purpose of this study is to simulate the effect of sublethal conditions on methicillin-resistant StapHylococcus aureus(MRSA)during food processing.In the experiment,two MRSA strains(MRSA6 and MRSA18)from pork with different background genes were selected,and they were treated with common disinfectants,low temperature,acid-base,and osmotic stress.The growth,virulence and resistance genes expression changes of the two strains before and after the treatment were investigated.The experimental results showed that the expression of virulence and resistance genes carried by the strains increased to varying degrees after benzalkonium bromide stress.Peracetic acid could promote and inhibit the expression of strain resistance genes,and inhibit the expression of virulence genes.Sodium hypochlorite could inhibit the expression of genes carried by the strain;low temperature,hypertonicity and alkali stress all could inhibit the expression of related genes of the strain;after acid stress treatment,the expression of mecA in MRSA 6 could be significantly promoted.The resistance genes all showed inhibitory effects.The minimum inhibitory concentration(MIC)of peracetic acid on the strain was 0.03%,the MIC of sodium hypochlorite on the strain was 0.17%,and the MIC of triceramide on the strain was 0.0005%,which were all lower than the recommended concentration of disinfectant.Low temperature stress had no obvious effect on the growth of the strains;55℃stress had a good inhibitory effect on the strain,and 60℃high temperature could achieve a better killing effect.The strains showed tolerance to hypertonic environment,and the growth of the strains was inhibited at a concentration of 35%sodium chloride.Low acid environment(pH 2)had a good inhibitory effect on the growth of strains.The alkaline environment had no obvious effect on the growth of the strains.In this study,it was found that the sublethal environmental conditions of conventional food processing might increase the virulence and resistance of strains by exploring the eff

关 键 词：耐甲氧西林金黄色葡萄球菌 胁迫条件 亚致死损伤 毒力和抗性基因表达 

分 类 号：TS201.3[轻工技术与工程—食品科学]