Cookson A L, Taylor S C S, Bennett J, Thomson-Carter F, Attwood G T
Rumen Microbial Functional Genomics Group, Metabolism and Microbial Genomics, AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand.
N Z Vet J. 2006 Apr;54(2):78-84. doi: 10.1080/00480169.2006.36616.
To serotype a subset of Shiga toxin-producing Escherichia coli (STEC) isolates from cattle and sheep to determine whether any corresponding serotypes have been implicated in human diarrhoeal disease, both in New Zealand and worldwide, and to examine the distribution of STEC and enteropathogenic Escherichia coli (EPEC) amongst cattle (calves, heifers and dairy) and sheep (lambs, rams and ewes), to assess whether carriage of identified bacterial genotypes may be associated with a particular age of animal.
Recto-anal mucosal swabs (RAMS) were taken from 91 calves, 24 heifers and 72 dairy cattle, and 46 lambs, 50 ewes and 36 rams, from four sites in the Manawatu and Rangitikei regions of New Zealand. Strains of E. coli selected from primary isolation plates were subjected to a multiplex polymerase chain reaction (PCR), to determine the presence of Shiga toxin genes (stx1 and stx2) and the E. coli attaching and effacing gene (eae).
Overall, 186/319 (58.3%) animals sampled were positive for stx1, stx2, or eae isolates. More sheep (43.9%) were stx1-positive than cattle (2.7%; p = 0.036), and amongst sheep more lambs and ewes were stx1-positive than rams (p = 0.036). Amongst cattle, more calves and heifers were eae-positive than dairy cows (p = 0.030). Two or more different STEC were isolated from at least 28 (9%) animals (three cattle and 25 sheep), based on their stx/eae genotype. Enterohaemolysin genes were found in 39/51 (76%) isolates serotyped. Twenty-one different serotypes were detected, including O5:H-, O9:H51, O26:H11, O84:H-/H2 and O149:H8 from cattle, and O26:H11, O65:H-, O75:H8, O84:H-, O91:H-, O128:H2 and O174:H8 from sheep; O84:H-, O26:H11, O5:H-, O91:H- and O128:H2 serotypes have been associated with human disease.
If nationally representative, this study confirms that cattle and sheep in New Zealand may be a major reservoir of STEC serotypes that have been recognised as causative agents of diarrhoeal disease in humans. Distribution of STEC and EPEC in cattle and sheep indicates that direct contact with, in particular, calves or their faeces, or exposure to environments cross contaminated with ruminant faeces, may represent an increased risk factor for human disease in New Zealand.
对从牛和羊中分离出的一部分产志贺毒素大肠杆菌（STEC）菌株进行血清分型，以确定在新西兰和全球范围内，是否有任何相应血清型与人类腹泻病有关，并研究STEC和肠致病性大肠杆菌（EPEC）在牛（犊牛、小母牛和奶牛）和羊（羔羊、公羊和母羊）中的分布情况，评估所鉴定的细菌基因型携带情况是否可能与特定年龄的动物有关。
从新西兰马纳瓦图和朗伊蒂凯地区的四个地点采集了91头犊牛、24头小母牛和72头奶牛，以及46只羔羊、50只母羊和36只公羊的直肠 - 肛门黏膜拭子（RAMS）。从初次分离平板上挑选出的大肠杆菌菌株进行多重聚合酶链反应（PCR），以确定志贺毒素基因（stx1和stx2）和大肠杆菌黏附并损毁基因（eae）的存在情况。
总体而言，在采样的319只动物中，有186只（58.3%）stx1、stx2或eae分离株呈阳性。stx1阳性的绵羊（43.9%）比牛（2.7%）更多（p = 0.036），在绵羊中，stx1阳性的羔羊和母羊比公羊更多（p = 0.036）。在牛中，犊牛和小母牛eae阳性的比奶牛更多（p = 0.030）。根据stx/eae基因型，从至少28只（9%）动物（3头牛和25只羊）中分离出两种或更多不同的STEC。在51株进行血清分型的分离株中，有�9株（76%）检测到肠溶血素基因。检测到21种不同的血清型，包括来自牛的O5:H-、O9:H51、O26:H11、O84:H-/H2和O149:H8，以及来自羊的O26:H11、O65:H-、O75:H8、O84:H-、O91:H-、O128:H2和O174:H8；O84:H-、O26:H11、O5:H-、O91:H-和O128:H2血清型与人类疾病有关。
如果具有全国代表性，本研究证实新西兰的牛和羊可能是已被确认为人类腹泻病病原体的STEC血清型的主要储存宿主。STEC和EPEC在牛和羊中的分布表明，在新西兰，特别是直接接触犊牛或其粪便，或暴露于被反刍动物粪便交叉污染的环境，可能是人类疾病的一个增加的风险因素。
