Duoss-Jennings Heather A, Schmidt Ty B, Callaway Todd R, Carroll Jeffery A, Martin James M, Shields-Menard Sara A, Broadway Paul R, Donaldson Janet R
Department of Animal Science, Iowa State University, Ames, IA, USA.
Int J Microbiol. 2013;2013:398320. doi: 10.1155/2013/398320. Epub 2013 Jan 17.
Citrus byproducts (CBPs) are utilized as a low cost nutritional supplement to the diets of cattle and have been suggested to inhibit the growth of both Escherichia coli O157:H7 and Salmonella. The objective of this study was to examine the effects in vitro that varying concentrations of CBP in the powdered or pelleted variety have on the survival of Shiga-toxin Escherichia coli (STEC) serotypes O26:H11, O103:H8, O111:H8, O145:H28, and O157:H7 in bovine ruminal microorganism media. The O26:H11, O111:H8, O145:H28, and O157:H7 serotypes did not exhibit a change in populations in media supplemented with CBP with either variety. The O103:H8 serotype displayed a general trend for an approximate 1log(10) reduction in 5% powdered CBP and 20% pelleted CBP over 6 h. There was a trend for reductions in populations of a variant form of O157:H7 mutated in the stx1 and stx2 genes in higher concentrations of CBP. These results suggest that variations exist in the survival of these serotypes of STEC within mixed ruminal microorganism fluid media when supplemented with CBP. Further research is needed to determine why CBPs affect STEC serotypes differently.
柑橘副产品（CBPs）被用作牛饲料的低成本营养补充剂，并且有人提出它能抑制大肠杆菌O157:H7和沙门氏菌的生长。本研究的目的是检测粉状或颗粒状不同浓度的CBP在体外对牛瘤胃微生物培养基中志贺毒素大肠杆菌（STEC）血清型O26:H11、O103:H8、O111:H8、O145:H28和O157:H7存活情况的影响。O26:H11、O111:H8、O145:H28和O157:H7血清型在添加了任何一种形式CBP的培养基中数量均未出现变化。O103:H8血清型在6小时内，在添加5%粉状CBP和20%颗粒状CBP的培养基中呈现出大致约1log(10)数量减少的总体趋势。在较高浓度的CBP中，stx1和stx2基因发生突变的O157:H7变异形式数量有减少的趋势。这些结果表明，在添加CBP的混合瘤胃微生物液体培养基中，这些STEC血清型的存活情况存在差异。需要进一步研究以确定CBP对STEC血清型产生不同影响的原因。
