Escherichia coli can be divided into several distinct phylogenetic groups that differ in their capacity to cause disease. However, what drives the relative abundance of these different phylogenetic groups in the commensal intestinal community of humans is poorly understood. This study investigated how host age and sex influences E. coli community structure in humans. Faecal samples were collected from 205 outpatients in Australia. Different strains within each sample were identified using rep‐PCR profiles and their phylogenetic group membership was determined by quadruplex PCR. Female individuals carrying a dominant B2 strain were found to possess fewer strains than those carrying dominant A or B1 strains. Additionally, strains from the same phylogenetic group were more likely to co‐occur in females. By contrast, strain diversity and phylogenetic group associations did not differ significantly from random in males. Host age was found to have a significant effect on the phylogenetic group of the dominant strain. Together these findings indicate that the distribution of the different phylogenetic groups within the human intestinal tract may be mediated by a complex interaction between the host environment and the competitive interactions between strains.

中文翻译：

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人类宿主内系统发育B2型大肠杆菌菌株的性别依赖性竞争优势。

È scherichia大肠杆菌可以分为在其能力，以引起疾病不同几个不同的系统发生的基团。但是，人们对人类共生肠道群落中这些不同的系统发育群体相对丰富的驱动因素知之甚少。这项研究调查了主机年龄和性别如何影响Ë 。大肠杆菌人类的社区结构。从澳大利亚的205位门诊患者中收集了粪便样本。使用rep-PCR谱图鉴定每个样品中的不同菌株，并通过四链PCR确定其系统进化组成员。发现携带显性B2株的女性个体所携带的菌株少于携带显性A或B1株的个体。此外，来自同一系统发育组的菌株更可能在女性中同时发生。相比之下，男性中的菌株多样性和系统发生群体的关联与随机性没有显着差异。发现宿主年龄对显性菌株的系统发生组有显着影响。