Moyo Sabrina J, Maselle Samwel Y, Matee Mecky I, Langeland Nina, Mylvaganam Haima
Department of Microbiology and Immunology, School of Medicine, Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania.
BMC Infect Dis. 2007 Aug 9;7:92. doi: 10.1186/1471-2334-7-92.
Relatively few studies have been done in Tanzania to detect and classify diarrheagenic Escherichia coli (DEC) strains among children with diarrhea. This study aimed at investigating DEC among children in Dar es Salaam aged less than five years hospitalized due to acute/persistent diarrhea.
DEC were isolated from stool samples collected from two hundred and eighty children with acute/persistent diarrhea at Muhimbili National Hospital and Ilala and Mwananyamala Municipal Hospitals in Dar es Salaam. A multiplex PCR system method was used to detect a species specific gene for E.coli and ten different virulence genes for detection of five pathogroups of DEC namely enteroaggregative- (EAEC), enteropathogenic- (EPEC), enterotoxigenic- (ETEC), enteroinvasive- (EIEC) and enterohemorghagic- Escherichia coli (EHEC).
Sixty-four patients (22.9%) harbored DEC. Forty-one of them (14.6%) were categorized as EAEC. Most of the EAEC (82.9%) were classified as typical EAEC possessing the aggR gene, and 92.6% carried the aat gene. Isolates from thirteen patients were EPEC (4.6%) and most of these (92.3%) were typical EPEC with both eae and bfpA genes. Ten isolates were identified as ETEC (3.6%) with only the heat stable toxin; either st1a or st1b but not both. Age wise, EAEC and EPEC were significantly more prevalent among the age group 0-6 months (p < 0.05). Genes for EHEC (stx1 and stx2) and EIEC (ial) were not detected in this study group.
The results show a high proportion of DEC among Tanzanian children with diarrhea, with typical EAEC and typical EPEC predominating. The use of primers for both variants of ST1 (st1a and st1b) increased the sensitivity for detection of ETEC strains.
在坦桑尼亚，针对腹泻儿童中致泻性大肠杆菌（DEC）菌株的检测和分类研究相对较少。本研究旨在调查达累斯萨拉姆市因急性/持续性腹泻住院的5岁以下儿童中的DEC情况。
从达累斯萨拉姆市穆希姆比利国家医院、伊拉拉市立医院和姆瓦纳尼亚马拉市立医院的280名急性/持续性腹泻儿童的粪便样本中分离DEC。采用多重聚合酶链反应（PCR）系统方法检测大肠杆菌的种特异性基因以及用于检测DEC五个致病群（即肠集聚性大肠杆菌（EAEC）、肠致病性大肠杆菌（EPEC）、产肠毒素大肠杆菌（ETEC）、肠侵袭性大肠杆菌（EIEC）和肠出血性大肠杆菌（EHEC））的十种不同毒力基因。
64名患者（22.9%）携带DEC。其中41名（14.6%）被归类为EAEC。大多数EAEC（82.9%）被归类为具有aggR基因的典型EAEC，92.6%携带aat基因。13名患者的分离株为EPEC（4.6%），其中大多数（92.3%）为同时具有eae和bfpA基因的典型EPEC。10株分离株被鉴定为ETEC（3.6%），仅携带热稳定毒素；即st1a或st1b，但不同时携带两者。按年龄划分，EAEC和EPEC在0至6个月龄组中显著更常见（p<0.05）。本研究组未检测到EHEC（stx1和stx2）和EIEC（ial）的基因。
结果显示，坦桑尼亚腹泻儿童中DEC比例较高，以典型EAEC和典型EPEC为主。使用针对ST1两种变体（st1a和st1b）的引物提高了ETEC菌株的检测灵敏度。
