Pasquali Frédérique, Lucchi Alex, Braggio Simonetta, Giovanardi Davide, Franchini Achille, Stonfer Maurizio, Manfreda Gerardo
Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia, Italy.
Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia, Italy.
Vet Microbiol. 2015 Aug 5;178(3-4):230-7. doi: 10.1016/j.vetmic.2015.05.007. Epub 2015 May 18.
Escherichia coli is a normal inhabitant of the intestinal tract of chickens, but when an imbalance in the gut microbiota occurs, E. coli may overgrow and cause extraintestinal infections. The aims of this study were to assess the distribution and spread of E. coli isolates with specific phylogenetic groups and antimicrobial resistance characters among asymptomatic breeder flocks and their broiler progenies with early symptoms of colibacillosis. Broiler flocks were treated with lincospectin during the first week of life and sampled at one, 21 and 42 days. The majority of the 363 E. coli isolates belonged to phylogenetic group A (53.17%), followed by groups D (23.14%), B1 (19.28%) and B2 (4.41%). In broilers, group A was the most represented in birds of 21 and 42 days of age whereas group B1 was the most represented phylogroup in one-day old chicks. More than 90.00% of the isolates were resistant to one or more antimicrobials. Along the life-time of broilers, no differences were found on the occurrence of resistant isolates except for the number of E. coli with elevated MIC to spectinomycin, which increased significantly after the lincospectin treatment. According to XbaI-macrorestriction analysis, a high genetic diversity among E. coli isolates was underlined. Four antimicrobial resistant E. coli isolates of phylogroups A, B1 and D collected from breeders showed similar PFGE patterns to five isolates collected from the respective broiler progenies suggesting a potential spread of these isolates from breeders to broilers.
大肠杆菌是鸡肠道的正常栖居菌，但当肠道微生物群出现失衡时，大肠杆菌可能过度生长并引发肠外感染。本研究的目的是评估具有特定系统发育群和抗菌耐药特征的大肠杆菌分离株在无症状种鸡群及其出现大肠杆菌病早期症状的肉鸡后代中的分布和传播情况。肉鸡群在出生后第一周用林可大观霉素进行治疗，并在1天、21天和42天进行采样。363株大肠杆菌分离株中，大多数属于系统发育群A（53.17%），其次是群D（23.14%）、B1（19.28%）和B2（4.41%）。在肉鸡中，群A在21日龄和42日龄的鸡中占比最高，而群B1是1日龄雏鸡中占比最高的系统发育群。超过90.00%的分离株对一种或多种抗菌药物耐药。在肉鸡的整个生命周期中，除了对大观霉素MIC升高的大肠杆菌数量在林可大观霉素治疗后显著增加外，耐药分离株的出现情况没有差异。根据XbaI宏限制性分析，强调了大肠杆菌分离株之间存在高度的遗传多样性。从种鸡中收集的4株系统发育群A、B1和D的抗菌耐药大肠杆菌分离株与从相应肉鸡后代中收集的5株分离株显示出相似的PFGE模式，表明这些分离株可能从种鸡传播到肉鸡。
