生长环境对消毒剂灭活粪肠球菌影响效果的试验研究

Effect of incubation condition on inactivation of Enterococcus Faecalis with disinfectant

通过改变培养基稀释度和培养温度以及添加无机生长元素(氯化钾、硫酸镁、三氯化铁)研究了自由氯、氯胺和二氧化氯对不同生长环境下所培养的粪肠球菌的灭活情况。结果表明,当粪肠球菌在100倍稀释的肉汤培养基上生长时,达到3log去除率氯和二氧化氯所需的Ct值分别增加了2.1和5.5倍,而氯胺所需的Ct值变化很小;将粪肠球菌的生长温度从22℃调整至44.5℃时,达到3log去除率氯胺所需的Ct值下降了2倍,自由氯和二氧化氯所需的Ct值则变化不大;在营养肉汤培养基中投加K+(4 mmol/L)、Mg2+(0.4 mmol/L)和Fe3+(0.08 mmol/L)后,粪肠球菌对自由氯和二氧化氯的抗性提高了,对氯胺的抗性则变化不大,达到3log去除率自由氯和二氧化氯所需的Ct值最大分别增加了约2.3和19倍。

Inactivation of Enterococcus faecalis by free chlorine, chloramine and chlorine dioxide was evaluated under different incubation conditions by varying dilution of nutrient media, culture temperature and adding inorganic element （KC1, MgSO4, FeCl3）. The results showed that 3log removal rate could be reached when the Enterococcus faecalis were incubated in 100-fold diluted nutrient broth solutions, Ct values for free chlorine and chlorine dioxide increased by 2. 1-fold and 5. 5-fold respectively, but little change Ct values for chloramine. Increase in incubation temperature from 22.5 to 44.5℃ for cultures resulted in a 2-fold decrease in Ct3log values for ehloramine, a similar change of temperature resulted in no significant in Ct3log values for chlorine and chlorine dioxide. Resistance of Enterococcus faecalis to chlorine and chlorine dioxide was improved after addition of K ＋ （4 mmol/L）, Mg2＋ （0. 4 mmol/L） and Fe3＋ （0.08 mmol/L） to cultures during incubation, but the resistance to chloramine was not changed, the maximun Ct values of free chlorine and chlorine dioxide reaching 3log removal rate could increase by 2.3-fold and 19-fold respectively.