大肠埃希菌O157：H7家蝇实验带菌消长的研究

目的采用大肠埃希菌O157∶H7-EDL933株,实验感染家蝇,观察家蝇体内外感染和带菌消长情况。方法点滴法体外定量染菌,剂量为1μ（l菌悬液浓度为8.0×10^5～1.9×10^7cfu/ml）,并采用昆虫单虫单管方法饲养观察。结果家蝇经体外染菌,获得体内外带菌,体外带菌时间中位数为（96.0±15.3）h（95%CI：66.0～126.0h）;体内中位数为（144.0±17.3）h（95%CI：110.2～177.8h）;家蝇体内外带菌消长差异无统计学意义（χ^2=0.74,P=0.388）,家蝇最长带菌时间至少216h（9d）。结论研究结果提示,家蝇不仅是O157∶H7疾病传播的媒介,更重要的可能是人类感染潜在的贮存宿主。

Dynamics of Escherichia coli O157:H7 in infected Musca domestica

Objective To determine the infection status and dynamics in vivo and ex vivo of Escherichia coli O157∶H7-EDL933 in the infected Musca domestica. Methods In vitro topical application of strains was employed to quantitatively infect the experimental flies, 1 μl apiece （the concentration of bacterial suspension was 8.0×10^5～1.9×10^7 cfu/ml）. Each fly was bred in one test tube for observation. Results The M. domestica infected in vitro carried the bacteria both in vivo and ex vivo. The median bacteria-carrying duration ex vivo was （96.0±15.3） h （95%CI： 66.0-126.0 h）, and the median bacteria-carrying duration in vivo was （144.0 ±17.3） h （95%CI： 110.2-177.8 h）. There was no significant difference between the bacteria-carrying dynamics in vivo and ex vivo （χ^2=0.74, P=0.388）. The longest bacteria-carrying duration of M. domestica was at least 216 h （9 d）. Conclusion M. domestica was not only the probable vector of E. coli O157∶H7, but also a potential reservoir host for human infection thereof.