Thibodeau Alexandre, Quessy Sylvain, Guévremont Evelyne, Houde Alain, Topp Edward, Diarra Moussa Sory, Letellier Ann
University of Montreal, Faculty of Veterinary Medicine, 3200 rue Sicotte, Saint-Hyacinthe, Quebec J2S 2M2.
Can J Vet Res. 2008;72(2):129-36.
Antibacterial agents such as zinc bacitracin (ZB) and virginiamycin (VG) are used as growth promoting agents (GP) in broiler chicken production. The objective of this study was to evaluate the effect of the use of ZB and VG on the emergence of antibacterial resistance in a commercial broiler chicken farm. Three trials were conducted using 3 different diets: one without antibacterial agents, one containing VG, and one with ZB. Escherichia coli and Enterococcus spp. strains were isolated and tested for their susceptibility to various antibacterial agents. The occurrence of the resistance genes vatD, ermB, and bcrR in Enterococcus spp. isolates was determined by polymerase chain reaction (PCR). Comparative quantification of vatD and bcrR genes in total deoxyribonucleic acid (DNA) extracts from litter was done by SYBR Green Real-Time PCR (QPCR). Escherichia coli and Enterococcus spp. isolates from diet groups had different levels of resistance to various antibacterial agents over time. These GPs did not select for specific antibacterial agent resistance (AAR) in Enterococcus spp. The use of GPs seemed to lower the percentage of E. coli isolates resistant to some antibacterial agents. The presence of the bcrR gene could not explain all resistant phenotypes to ZB. Genes other than vatD and ermB might be involved in the resistance to VG in Enterococcus spp. Use of GPs was not associated with presence of the bcrR gene in DNA extracts from litter, but use of VG was associated with vatD presence.
诸如杆菌肽锌（ZB）和维吉尼亚霉素（VG）等抗菌剂在肉鸡生产中用作生长促进剂（GP）。本研究的目的是评估在一家商业肉鸡养殖场中使用ZB和VG对细菌耐药性出现的影响。使用三种不同的日粮进行了三项试验：一种不含抗菌剂，一种含有VG，一种含有ZB。分离出大肠杆菌和肠球菌菌株，并测试它们对各种抗菌剂的敏感性。通过聚合酶链反应（PCR）测定肠球菌分离株中耐药基因vatD、ermB和bcrR的存在情况。通过SYBR Green实时荧光定量PCR（QPCR）对垫料总脱氧核糖核酸（DNA）提取物中的vatD和bcrR基因进行比较定量。随着时间的推移，日粮组的大肠杆菌和肠球菌分离株对各种抗菌剂的耐药水平不同。这些生长促进剂并未在肠球菌中选择特定的抗菌剂耐药性（AAR）。生长促进剂的使用似乎降低了对某些抗菌剂耐药的大肠杆菌分离株的百分比。bcrR基因的存在无法解释所有对ZB的耐药表型。除vatD和ermB之外的基因可能与肠球菌对VG的耐药性有关。生长促进剂的使用与垫料DNA提取物中bcrR基因的存在无关，但VG的使用与vatD的存在有关。
