5种致泻大肠埃希氏菌不同浓度下的国标法检出率分析  

Analysis of the Detection Rate of 5 Kinds of Diarrheagenic Escherichia Coli at Different Concentrations by National Standard Method

作　　者：胡春红 陆其聪 HU Chunhong;LU Qicong(Sichuan Light Industry Research and Design Institute Co.,Ltd.,Chengdu 610081,China)

机构地区：[1]四川省轻工业研究设计院有限公司,四川成都610081

出　　处：《食品安全导刊》2023年第28期95-97,104,共4页China Food Safety Magazine

摘　　要：目的:研究5种致泻大肠埃希氏菌使用GB 4789.6—2016法检测时,不同初始浓度下,二次增菌取不同接种体积的检出率。方法:不同初始浓度下(1~3 CFU·mL^(-1),10~30 CFU·mL^(-1),100~300 CFU·mL^(-1))的5种致泻大肠埃希氏菌加入营养肉汤增菌后,取不同体积(10μL、50μL、100μL、500μL、1000μL)的预增菌液接种于肠道增菌肉汤管中,培养后划线于伊红美蓝琼脂(Eosin-Methylene Blue,EMB)和麦康凯琼脂(MacConkey Agar,MAC)平板,观察并记录平板中菌落生长情况,计算检出率。结果:5种致泻大肠埃希氏菌接种量在10 CFU及以上时,二次增菌时取10μL预增菌液至肠道增菌肉汤中,均能检出。5种致泻大肠埃希氏菌接种量在1~3 CFU时,二次增菌时取10μL和50μL预增菌液至肠道增菌肉汤中,平均检出率均不能达到100%;二次增菌时接种体积增加到100μL时,肠道集聚性大肠埃希菌EAEC(CICC24186)、肠出血性大肠埃希菌EHEC(CICC24187)、产肠毒素大肠埃希菌ETEC(CICC24190)的检出率能达到100%,而肠道侵袭性大肠埃希菌EIEC(CICC24188)、肠道致病性大肠埃希菌EPEC(CICC24189)的检出率仍不能达到100%。结论:在实际检测工作中,在所检样品中致泻大肠埃希氏菌含量较低时,可以考虑增加二次增菌的接种量,减少漏检可能。Objective:To study the detection rates of 5 types of diarrhea causing Escherichia coli using the GB 4789.6—2016 method at different initial concentrations and different inoculation volumes for secondary enrichment.Method:Five types of diarrhea causing Escherichia coli at different initial concentrations(1~3 CFU·mL^(-1),10~30 CFU·mL^(-1),100~300 CFU·mL^(-1))were added to nutrient broth for enrichment,and different volumes(10μL,50μL,100μL,500μL,1000μL)inoculate the pre enrichment solution into the intestinal enrichment broth tube,and after cultivation,line it on eosin methylene blue(EMB)and macconkey agar(MAC)plates.Observe and record the bacterial colony growth in the plates,and calculate the detection rate.Result:When the inoculation amount of 5 types of diarrhea causing Escherichia coli was 10 CFU or above,10μL of pre enriched liquid was taken into the intestinal enrichment broth during the second enrichment,and all of them could be detected.When the inoculation amount of 5 types of diarrhea causing Escherichia coli is 1~3 CFU,10μL and 50μL of pre enriched liquid are taken during the second enrichment into the intestinal enrichment broth,and the average detection rate cannot reach 100%;when the inoculation volume increases to 100μL during the second enrichment,the detection rates of E.coli EAEC(CICC24186),E.coli EHEC(CICC24187),and E.coli ETEC(CICC24190)can reach 100%,while the detection rates of invasive E.coli EIEC(CICC24188)and pathogenic E.coli EPEC(CICC24189)cannot reach 100%.Conclusion:In practical testing work,when the content of Escherichia coli causing diarrhea in the tested samples is low,it can be considered to increase the inoculation amount of secondary enrichment to reduce the possibility of missed detection.

关 键 词：致泻大肠埃希氏菌 国家标准方法 检出率 

分 类 号：TS207.4[轻工技术与工程—食品科学]