一株黄瓜源肠集聚性大肠埃希氏菌耐药及生长预测模型分析

Drug resistance and growth prediction model analysis of an enteroaggregative Escherichia coli strain isolated from cucumber

中文关键词:  黄瓜  肠集聚性大肠埃希氏菌  耐药  生长预测模型

英文关键词:cucumber  enteroaggregative Escherichia coli  drug resistance  growth prediction model

中文摘要:

      目的 考查一株黄瓜源肠集聚性大肠埃希氏菌(enteroaggregative Escherichia coli, EAEC)的耐药情况, 并建立其生长预测模型。方法 将采集的黄瓜样品进行大肠埃希氏菌的分离和鉴定, 通过聚合酶链式反应(polymerase chain reaction, PCR)对EAEC特征性毒力基因进行确认, 并通过VITEK 2 Compact全自动微生物药敏系统进行18种抗生素的耐药性分析; 以分离鉴定的EAEC为研究对象, 监测其在4、15、25、35℃贮藏条件下在黄瓜上的生长数据, 绘制生长曲线, 采用SLogistic模型进行拟合, 建立黄瓜中EAEC生长预测模型。结果 自黄瓜中分离到一株EAEC, 携带aggR和astA毒力基因, 对磺胺类药物复方新诺明高度耐药。4、15、25、35℃贮藏条件下EAEC在黄瓜上的生长用SLogistic模型拟合的相关系数都大于0.95, 该模型可以有效地反应EAEC在黄瓜上的生长情况。结论 黄瓜上存在EAEC污染风险, EAEC的耐药性进一步加剧生食黄瓜的安全风险。通过SLogistic方程可以有效建立不同温度条件下EAEC在黄瓜上的生长预测模型, 对生食黄瓜的加工、供餐等过程中食源性致病菌风险控制提供参考依据。

英文摘要:

      Objective To investigate the drug resistance of an enteroaggregative Escherichia coli (EAEC) strain from cucumber, and establish an effective growth prediction model. Methods Escherichia coli was isolated and identified from cucumber samples. The characteristic virulence genes of EAEC were confirmed by polymerase chain reaction (PCR), and drug resistances of 18 kinds of antibiotics were analyzed by the VITEK 2 Compact automatic microbial drug sensitivity system. The growth data of the identified EAEC on cucumber culturing at 4, 15, 25 and 35℃ were collected, fitted the growth curves with the SLogistic model, and finally established the growth prediction model of EAEC on cucumber. Results A strain of EAEC was isolated from cucumber, carrying aggR and astA virulence genes and highly resistant to trimethoprim/sulfamethoxazole. The EAEC growth model at different 4 temperatures could be fitted well on cucumber by the SLogistic model, with effective parameters as correlation coefficients all above 0.95, indicating that they could be used to predict the growth dynamics of EAEC on cucumbers. Conclusion There is a risk of EAEC contamination on cucumbers, and the resistance of EAEC further aggravates the safety risk of raw cucumbers. The growth prediction model of EAEC on cucumber can be effectively established by the SLogistic model, which can provide references for the risk control of food-borne pathogens in the process of raw cucumber at different temperatures.