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目的研究经-20℃冷冻损伤的大肠菌群在乳糖胆盐发酵培养基上的生长状况。方法选用大肠埃希氏菌、阴沟肠杆菌、弗劳地枸橼酸杆菌、产气克雷伯氏菌等4株大肠菌群菌株为研究菌株,经-20℃冷冻贮存不同时间后,分析在乳糖胆盐发酵培养基的生长。结果-20℃冷冻损伤大肠埃希氏菌、阴沟肠杆菌、弗劳地枸橼酸杆菌、产气克雷伯氏在菌乳糖胆盐发酵培养基生长抑制;大肠埃希氏菌、弗劳地枸橼酸杆菌、阴沟肠杆菌的损伤率大于产气克雷伯氏菌的损伤率,冷冻1d后,其损伤率高达70%以上;阴沟肠杆菌、产气克雷伯氏菌的死亡率大于大肠埃希氏菌、弗劳地枸橼酸杆菌,冷冻1d后,其死亡率均高达80%以上。结论-20℃冷冻损伤大肠菌群在常规检测中使用的乳糖胆盐发酵培养基生长抑制,提示应探索有效的检测方法,以修复冷冻损伤大肠菌群。
Objective To study the growth of coliforms damaged by freezing at -20 ℃ on lactose bile salts fermentation medium. Methods Four strains of Escherichia coli, Enterobacter cloacae, Citrobacter freundii and Klebsiella pneumoniae were selected as the research strains. After frozen storage at -20 ℃ for different time, Growth of lactose bile salt fermentation medium. Results Frozen Escherichia coli, Enterobacter cloacae, Citrobacter freundii at -20 ℃, Klebsiella pneumoniae growth inhibition in bacterial lactobacillus bile salt fermentation medium; Escherichia coli, Citrobacter, Enterobacter cloacae injury rate is greater than the production of Klebsiella pneumoniae injury rate, frozen 1d, the damage rate as high as 70%; Enterobacter cloacae, Klebsiella pneumoniae mortality is greater than Escherichia coli, Freund Citrobacter, frozen 1d, the mortality rate was as high as 80%. Conclusion The growth inhibition of lactose bile salt fermentation medium used in routine tests at -20 ℃ freezing colibacillosis suggests that an effective detection method should be explored to repair the frozen-damaged coliforms.