两株大肠杆菌对消毒剂及冷热抗力的试验比较

为比较两株大肠杆菌对消毒剂与冷热的抗力,进行了悬液抑菌抑菌、杀菌试验、结果,碘伏．醋酸氯已定同忆乙醇一样,对大肠杆菌8099株和ATCC11229株最小抑菌浓度或最小杀菌浓度均相近;在4℃放置1~7d,大肠杆菌8099株的存活率为95.40%-85.44%,ATCC11229株者为92．40%-79.74%,差异尤显著性(P＞0．05);经100℃作川1~5min,两株大肠杆菌的死亡率相同(均为99．99%~100%);以56℃作用5~30 min 或80℃作用1-10min,8099株死亡率分别为50．8%-99．68%与99.76%-99.99%,ATCC11229株死亡率分别为78．80%~99．96%与99.85%-100%,8099株死亡率均低于ATCC11229株。表明大肠杆菌8099株对湿热的抗力强于ATCC11229株.

EXPERIMENTAL COMPARISON OF RESISTANCE OF TWO STRAINS OF Escherichia coli TO DISINFECTANTS, COLD AND HEAT

In order to compare the resistance of 2 strains of Escherichia coli to the disinfectants, cold and heat, suspension baclcriostalic and bactericidal tests were carried out. The results showed that same as ethyl alcohol, either the minimum bacteriostatic concentrations or the minimum bactericidal concentrations of iodophor and chlorhexidinc acetate against strain 8099 and strain ATCC 11229 of Escherichia coli were approximate. After being kept at 4℃for 1-7 days, the survival rates of strain 8099 and strain ATCC 11229 of E. coli were 95.40%-85.44% and 92.40%-79.74% respectively with no significant difference (p>0.05). After ex posure to 100℃for 1-5min, the mortality rates of the two strains were identical (both were 99.99%-100%). After exposure to 56℃for 5-30 min or to 80℃ for 1-10 min, the mortali ty rates of the strain 8099 were 50.38%-99.68% and 99.76%-99.99% respectively, and those of the strain ATCC 11229 were 78.80%-99.96% and 99.85%-100% respectively. The mortality rates of the strain 8099 were lower than those of the strain ATCC 11229 after these two types of exposure, indicating that the resistance of strain 8099 of E. coli to wet heat is higher than that of the strain ATCC 11229.