Fecal Shedding of Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Feedlot Cattle Vaccinated with an Escherichia coli O157:H7 SRP Vaccine or Fed a Lactobacillus-Based Direct-Fed Microbial
Fecal Shedding of Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Feedlot Cattle Vaccinated with an Escherichia coli O157:H7 SRP Vaccine or Fed a Lactobacillus-Based Direct-Fed Microbial
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DOI：
10.4315/0362-028x.jfp-13-358
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发表时间：
2014-05-01
影响因子：
2
通讯作者：
Nagaraja, T. G.
中科院分区：
文献类型：
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作者：
Cernicchiaro, N.;Renter, D. G.;Nagaraja, T. G.
本研究的目的是确定使用大肠杆菌是否会影响饲养场牛中非O157产滋贺毒素大肠杆菌（STEC）的粪便排出。大肠杆菌O157：H7疫苗或直接饲喂微生物（DFM），以及粪便中特定非O157 STEC血清群的脱落是否与O157或其他非O157 STEC血清群的脱落相关。40个围栏中的17，148头牛被随机分配接受两种干预措施中的一种，两种或两种都不接受（对照）：基于铁载体受体和孔蛋白的疫苗（E。colt SRP疫苗，两剂）和DFM产品（低剂量Bovamine）。从研究分配后约56天开始，每周从畜栏地面采集新鲜粪便样本（每栏30份样本），连续4周。采用11基因多重PCR检测法，检测从富集样本中提取的DNA中STEC O157和非O157血清群O26、O45、O103、O111、O121和O145以及4种主要毒力基因（stx（1）、stx（2）、eae和ehxA）。使用广义线性混合模型分析处理的影响，并对O血清群特异性基因的存在进行样本内比较。累积患病率测量结果表明，O157（14.6%），O26（10.5%）和O103（10.3%）是最流行的STEC O血清群。然而，疫苗、DFM或两者对饲养场牛中6个非O157 STEC血清群的粪便流行率没有显著影响（P > 0.05）。STEC血清群特异性基因的样本内比较表明，粪便排泄的大肠杆菌。牛中的Colt 0157与STEC O26、O45、O103和O121的粪便散毒概率增加相关（P < 0.05）。我们的研究表明，E.大肠杆菌O157：117疫苗，减少STEC O157粪便脱落，也没有DFM显着影响粪便脱落的非O157 STEC血清群，尽管事实上，最流行的非O157 STEC血清群往往同时发生在粪便样本中的O157 STEC菌株。
The objectives of this study were to determine whether fecal shedding of non-O157 Shiga toxin-producing Escherichia coli (STEC) in feedlot cattle was affected by the use of an E. coli O157:H7 vaccine or a direct-fed microbial (DFM) and whether the shedding of a particular non-O157 STEC serogroup within feces was associated with shedding of O157 or other non-O157 STEC serogroups. A total of 17,148 cattle in 40 pens were randomized to receive one, both, or neither (control) of the two interventions: a vaccine based on the siderophore receptor and porin proteins (E. colt SRP vaccine, two doses) and a DFM product (low-dose Bovamine). Fresh fecal samples (30 samples per pen) were collected weekly from pen floors for four consecutive weeks beginning approximately 56 days after study allocation. DNA extracted from enriched samples was tested for STEC O157 and non-O157 serogroups O26, O45, O103, O111, O121, and O145 and for four major virulence genes (stx(1), stx(2), eae, and ehxA) using an 11-gene multiplex PCR assay. Generalized linear mixed models were used to analyze the effects of treatments and make within-sample comparisons of the presence of O-serogroup-specific genes. Results of cumulative prevalence measures indicated that O157 (14.6%), O26 (10.5%), and O103 (10.3%) were the most prevalent STEC O serogroups. However, the vaccine, DFM, or both had no significant effect (P > 0.05) on fecal prevalence of the six non-O157 STEC serogroups in feedlot cattle. Within-sample comparisons of the presence of STEC serogroup-specific genes indicated that fecal shedding of E. colt 0157 in cattle was associated with an increased probability (P < 0.05) of fecal shedding of STEC O26, O45, O103, and O121. Our study revealed that neither the E. coli O157:117 vaccine, which reduced STEC O157 fecal shedding, nor the DFM significantly affected fecal shedding of non-O157 STEC serogroups, despite the fact that the most prevalent non-O157 STEC serogroups tended to occur concurrently with O157 STEC strains within fecal samples.