Genotypic and phenotypic characterization of Escherichia coli isolates from children with urinary tract infection and from healthy carriers.
Genotypic and phenotypic characterization of Escherichia coli isolates from children with urinary tract infection and from healthy carriers.
复制标题
从尿路感染儿童和健康携带者中分离出的大肠杆菌的基因型和表型特征。
DOI：
10.1097/inf.0b013e31828ba3f1
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Gilbert,GwendolynL
中科院分区：
文献类型：
--
作者：
Kudinha,Timothy;Johnson,JamesR;Andrew,ScottD;Kong,Fanrong;Anderson,Peter;Gilbert,GwendolynL
背景：尿路感染（UTI）在儿童中很常见，并且对发病率和死亡率有很大影响。主要原因是大肠杆菌，携带多种毒力相关因子 (VF)。然而，区分儿童尿路致病性大肠杆菌与健康儿童粪便共生体的具体特征尚未完全确定。方法：我们使用基于多重聚合酶链反应的反向线印迹测定、几种其他聚合酶链反应和表型方法来比较毒力特征的分布（22 个 VF 基因、UTI 相关 O 型、系统发育组、序列类型） 131 和所选 VF 的表达），在同一时间段收集的 212 份来自 ≤ 5 岁 UTI 儿童的大肠杆菌分离株（109 份膀胱炎和 103 份肾盂肾炎）和 115 份来自相似年龄的健康儿童的粪便分离株之间。结果：所研究的特征在肾盂肾炎中最常见，其次是膀胱炎分离株，在粪便分离株中不常见。八个 VF 基因可区分肾盂肾炎和膀胱炎分离株，但这 2 个 UTI 组的总 VF 评分相似。大多数研究的表型特征显示出从肾盂肾炎到膀胱炎再到粪便分离物的相似的患病率下降梯度。生物膜成分、curli 和纤维素的共表达与肾盂肾炎、系统发育组 B2、个体 VF 基因和较高的 VF 评分密切相关。三分之二 (67%) 的临床分离株属于系统发育群 B2，其中 12% 属于序列类型 131 克隆群，而粪便分离株的比例分别为 14% 和 1%。 结论：这些发现确定了特定毒力因子、O 型和毒力克隆群（序列类型 131）作为儿童 UTI 预防策略的潜在目标。
Background: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.Methods: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.Results: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.Conclusions: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.