Charles Sturt University, Leeds Parade, Orange, New South Wales, Australia.
Pediatr Infect Dis J. 2013 May;32(5):543-8. doi: 10.1097/INF.0b013e31828ba3f1.
Urinary tract infections (UTI) are common in children and contribute significantly to morbidity and mortality. The major cause is Escherichia coli, carrying multiple virulence-associated factors (VFs). However, the specific traits that distinguish childhood uropathogenic E. coli from fecal commensals of healthy children are incompletely defined.
We used a multiplex polymerase chain reaction-based reverse line blot assay, several additional polymerase chain reactions and phenotypic methods to compare distributions of virulence traits (22 VF genes, UTI-associated O types, phylogenetic groups, sequence type 131 and expression of selected VFs), between 212 E. coli isolates from children ≤ 5 years with UTI (109 cystitis and 103 pyelonephritis) and 115 fecal isolates from healthy children of similar age, collected during the same time period.
The studied traits were most prevalent among pyelonephritis, followed closely by cystitis isolates and were uncommon among fecal isolates. Eight VF genes differentiated pyelonephritis from cystitis isolates, but aggregate VF scores in these 2 UTI groups were similar. Most of the studied phenotypic characteristics showed a similar descending prevalence gradient from pyelonephritis, through cystitis, to fecal isolates. Coexpression of biofilm components, curli and cellulose, was strongly associated with pyelonephritis, phylogenetic group B2, individual VF genes and higher VF scores. Two-thirds (67%) of clinical isolates belonged to phylogenetic group B2 and, of these, 12% belonged to the sequence type 131 clonal group, compared with 14% and 1%, respectively, of fecal isolates.
These findings identify specific virulence factors, O types and a virulent clonal group (sequence type 131), as potential targets for UTI prevention strategies in children.
尿路感染（UTI）在儿童中很常见，对发病率和死亡率有重大影响。主要病因是携带多种毒力相关因子（VF）的大肠杆菌。然而，将儿童泌尿道致病菌与健康儿童粪便共生菌区分开来的特定特征尚未完全确定。
我们使用了基于多重聚合酶链反应的反向线印迹分析、几种额外的聚合酶链反应和表型方法，比较了 212 株来自≤5 岁患有 UTI（109 例膀胱炎和 103 例肾盂肾炎）的儿童和同期收集的 115 株来自健康儿童的粪便分离株的毒力特征分布（22 个 VF 基因、与 UTI 相关的 O 型、进化群、ST131 血清型和选定 VF 的表达）。
所研究的特征在肾盂肾炎中最为普遍，其次是膀胱炎分离株，在粪便分离株中则不常见。8 个 VF 基因可将肾盂肾炎与膀胱炎分离株区分开来，但这 2 个 UTI 组的总 VF 评分相似。研究的大多数表型特征都表现出从肾盂肾炎、膀胱炎到粪便分离株的相似下降流行梯度。生物膜成分、卷曲和纤维素的共同表达与肾盂肾炎、进化群 B2、个别 VF 基因和更高的 VF 评分密切相关。三分之二（67%）的临床分离株属于进化群 B2，其中 12%属于 ST131 克隆群，而粪便分离株分别为 14%和 1%。
这些发现确定了特定的毒力因子、O 型和一个毒力克隆群（ST131），可作为儿童 UTI 预防策略的潜在靶点。
