Oot R A, Raya R R, Callaway T R, Edrington T S, Kutter E M, Brabban A D
The Evergreen State College, Olympia WA 98505, USA.
Lett Appl Microbiol. 2007 Oct;45(4):445-53. doi: 10.1111/j.1472-765X.2007.02211.x.
To estimate the distribution and prevalence of both Escherichia coli O157 and O157:H7-infecting bacteriophages within a 50,000 head commercial beef feedlot.
Escherichia coli O157 was detected in approximately 27% of the individual samples, distributed across seven of the 10 pens screened. In a simple initial screen to detect O157:H7-infecting phages, none were detected in any pen or individual sample. In contrast, after a series of enrichment procedures O157:H7-infecting phages were detected in every pen and in the majority of the samples from most pens; virulent bacteriophages active against E. coli O157:H7 were detected post-enrichment from 39/60 (65%) of the feedlot samples, and 58/60 (approximately 97%) contained phage that infected E. coli B or O157:H7.
The data we present here indicates that we may be grossly underestimating the prevalence of O157:H7-infecting phages in livestock if we simply screen samples and that enrichment screening is required to truly determine the presence of phages in these ecosystems.
Our data suggest that O157:H7-infecting phages may play a role in the ecology and transient colonization of cattle by E. coli O157:H7. Further, this and previous data suggest that before starting in vivo pathogen eradication studies using phage or any other regime, test animals should be enrichment screened for phage to avoid erroneous results.
评估一个存栏50000头肉牛的商业饲养场中大肠杆菌O157及感染O157:H7的噬菌体的分布和流行情况。
在约27%的个体样本中检测到大肠杆菌O157，分布在筛查的10个畜栏中的7个。在一个简单的初始筛查中，未在任何畜栏或个体样本中检测到感染O157:H7的噬菌体。相比之下，经过一系列富集程序后，在每个畜栏以及大多数畜栏的大多数样本中都检测到了感染O157:H7的噬菌体；富集后，在39/60（65%）的饲养场样本中检测到了对大肠杆菌O157:H7有活性的烈性噬菌体，58/60（约97%）的样本含有感染大肠杆菌B或O157:H7的噬菌体。
我们在此呈现的数据表明，如果仅对样本进行筛查，可能会严重低估家畜中感染O157:H7的噬菌体的流行情况，需要进行富集筛查才能真正确定这些生态系统中噬菌体的存在。
我们的数据表明，感染O157:H7的噬菌体可能在大肠杆菌O157:H7对牛的生态作用和短暂定植中发挥作用。此外，本研究及之前的数据表明，在开始使用噬菌体或任何其他方案进行体内病原体根除研究之前，应对试验动物进行噬菌体富集筛查，以避免得出错误结果。
