Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
School of Environmental Sciences, Charles Sturt University, Thurgoona, NSW 2641, Australia.
J Med Microbiol. 2011 May;60(Pt 5):574-581. doi: 10.1099/jmm.0.027037-0. Epub 2011 Feb 3.
We investigated the population structures of faecal Escherichia coli in 30 healthy young adults (13 males and 17 females) aged between 20 and 45 years and 29 elderly adults (14 females and 15 males) aged between 65 and 77 years. In all, 1566 strains were typed with the PhPlate system and grouped into biochemical phenotypes (BPTs). Strains with shared BPTs were further typed using randomly amplified polymorphic DNA analysis. Forty-four per cent of the strains were shared between two or more age and gender groups. Elders had a significantly higher (P<0.001) number of BPTs (mean±standard error 3.3±0.27) than younger groups (1.82±0.27). Phylogenetic affiliation and virulence-associated genes (VAGs) of the strains showed that more than 80 % of the strains belonging to dominant types belonged to phylogroups B2 and D. Amongst dominant BPTs, phylogenetic group A was significantly associated with females (P<0.0001), and elders were more likely to carry group D (P<0.0124). Elderly males had a higher prevalence of VAGs than young males (P<0.0001) and young females (P<0.0005). We conclude that there is a lower prevalence of E. coli with uropathogenic properties in healthy young adults than in elders.
我们调查了 30 名健康的年轻成年人（13 名男性和 17 名女性，年龄在 20 至 45 岁之间）和 29 名老年成年人（14 名女性和 15 名男性，年龄在 65 至 77 岁之间）粪便大肠杆菌的种群结构。总共使用 PhPlate 系统对 1566 株进行了分型，并分为生化表型（BPT）。具有共享 BPT 的菌株进一步使用随机扩增多态性 DNA 分析进行分型。44%的菌株在两个或更多年龄和性别组之间共享。老年人的 BPT 数量明显更高（P<0.001）（平均值±标准误差 3.3±0.27）比年轻组（1.82±0.27）。菌株的系统发育相关性和毒力相关基因（VAG）表明，属于优势类型的菌株中超过 80%属于 B2 和 D 群。在优势 BPT 中，A 群与女性显著相关（P<0.0001），而老年人更可能携带 D 群（P<0.0124）。老年男性携带 VAG 的比例高于年轻男性（P<0.0001）和年轻女性（P<0.0005）。我们得出结论，健康的年轻成年人中具有尿路致病性的大肠杆菌的流行率低于老年人。
