背景

该研究使用从（1）皮肤和软组织感染，（2）呼吸道感染，（3）腹内感染和（4）生殖器涂片分离的一组407个人类肠外致病性大肠杆菌菌株（ExPEC）。该组用于细菌素生产，细菌素和毒力决定因素的流行以及系统发育分型的测试。将来自ExPEC菌株组的结果与我们之前发表的1283个粪便共生大肠杆菌菌株的分析数据进行比较。

结果

与粪大肠杆菌（54.2％; p <0.01）相比，该组ExPEC菌株中细菌生成的频率显着更高（63.1％）。 Microcin生产者和microcin决定簇在ExPEC菌株中占优势，而大肠杆菌素生产者和大肠菌素决定簇在粪便大肠杆菌中更频繁（p <0.01）。在一组ExPEC菌株中检测到较高的小菌素M产量和小菌素B17，大肠菌素Ib和Js的较低产量。与粪便大肠杆菌菌株（38.3％; p <0.01）相比，ExPEC菌株的系统发生组B2（52.6％）的流行率显着更高。

结论

人类ExPEC菌株在许多参数中显示与人类粪便菌株不同，包括细菌素生产，几种细菌素和毒力决定因子的流行，以及系统发育组的流行。这些参数的差异也在不同来源的ExPEC菌株的亚组内被鉴定。尽管一些microcin决定簇（mM，mH47）与毒性菌株相关，但其他细菌素类型（mB17，Ib和Js）与粪便菌群相关。
Background
The study used a set of 407 human extraintestinal pathogenic E. coli strains (ExPEC) isolated from (1) skin and soft tissue infections, (2) respiratory infections, (3) intra-abdominal infections, and (4) genital smears. The set was tested for bacteriocin production, for prevalence of bacteriocin and virulence determinants, and for phylogenetic typing. Results obtained from the group of ExPEC strains were compared to data from our previously published analyses of 1283 fecal commensal E. coli strains.
Results
The frequency of bacteriocinogeny was significantly higher in the set of ExPEC strains (63.1 %), compared to fecal E. coli (54.2 %; p < 0.01). Microcin producers and microcin determinants dominated in ExPEC strains, while colicin producers and colicin determinants were more frequent in fecal E. coli (p < 0.01). Higher production of microcin M and lower production of microcin B17, colicin Ib, and Js was detected in the set of ExPEC strains. ExPEC strains had a significantly higher prevalence of phylogenetic group B2 (52.6 %) compared to fecal E. coli strains (38.3 %; p < 0.01).
Conclusions
Human ExPEC strains were shown to differ from human fecal strains in a number of parameters including bacteriocin production, prevalence of several bacteriocin and virulence determinants, and prevalence of phylogenetic groups. Differences in these parameters were also identified within subgroups of ExPEC strains of diverse origin. While some microcin determinants (mM, mH47) were associated with virulent strains, other bacteriocin types (mB17, Ib, and Js) were associated with fecal flora.
https://bmcmicrobiol.biomedcentral.com/articles/10.1186/s12866-016-0835-z