Department of Urology, Naval Medical Center, San Diego, California 92134-5000, USA.
J Urol. 2012 Jul;188(1):236-41. doi: 10.1016/j.juro.2012.03.025. Epub 2012 May 15.
We hypothesized that virulence levels of Escherichia coli isolates causing pediatric urinary tract infections differ according to severity of infection and also among various uropathies known to contribute to pediatric urinary tract infections. We evaluated these relationships using in vitro cytokine interleukin-6 elicitation.
E. coli isolates were cultured from children presenting with urinary tract infections. In vitro cytokine (interleukin-6) elicitation was quantified for each isolate and the bacteria were grouped according to type of infection and underlying uropathy (neurogenic bladder, nonneurogenic bowel and bladder dysfunction, primary vesicoureteral reflux, no underlying etiology).
A total of 40 E. coli isolates were collected from children with a mean age of 61.5 months (range 1 to 204). Mean level of in vitro cytokine elicitation from febrile urinary tract infection producing E. coli was significantly lower than for nonfebrile strains (p = 0.01). The interleukin-6 response to E. coli in the neurogenic bladder group was also significantly higher than in the vesicoureteral reflux (p = 0.01) and no underlying etiology groups (p = 0.02).
In vitro interleukin-6 elicitation, an established marker to determine bacterial virulence, correlates inversely with clinical urinary tract infection severity. Less virulent, high cytokine producing E. coli were more likely to cause cystitis and were more commonly found in patients with neurogenic bladder and nonneurogenic bowel and bladder dysfunction, whereas higher virulence isolates were more likely to produce febrile urinary tract infections and to affect children with primary vesicoureteral reflux and no underlying etiology. These findings suggest that bacteria of different virulence levels may be responsible for differences in severity of pediatric urinary tract infections and may vary among different underlying uropathies.
我们假设引起小儿尿路感染的大肠杆菌分离株的毒力水平根据感染的严重程度以及已知导致小儿尿路感染的各种尿路病变而有所不同。我们使用体外细胞因子白细胞介素-6 诱导来评估这些关系。
从患有尿路感染的儿童中培养大肠杆菌分离株。对每个分离株进行体外细胞因子（白细胞介素-6）诱导的定量，并根据感染类型和潜在尿路病变（神经性膀胱、非神经性肠和膀胱功能障碍、原发性输尿管反流、无潜在病因）对细菌进行分组。
共从患有尿路感染的儿童中收集了 40 株大肠杆菌，平均年龄为 61.5 个月（范围 1 至 204 个月）。产热尿路感染产生的大肠杆菌体外细胞因子诱导的平均水平明显低于非发热菌株（p = 0.01）。神经性膀胱组中大肠杆菌对白细胞介素-6 的反应也明显高于输尿管反流（p = 0.01）和无潜在病因组（p = 0.02）。
体外白细胞介素-6 诱导，一种确定细菌毒力的既定标志物，与临床尿路感染严重程度呈反比相关。毒力较低、产生高细胞因子的大肠杆菌更有可能引起膀胱炎，并且更常见于神经性膀胱和非神经性肠和膀胱功能障碍的患者，而毒力较高的分离株更有可能引起发热性尿路感染，并影响原发性输尿管反流和无潜在病因的儿童。这些发现表明，不同毒力水平的细菌可能是导致小儿尿路感染严重程度不同的原因，并且可能因不同的潜在尿路病变而异。
