BACKGROUND This study was aimed to investigate the intestinal microbiota in racing pigeons with regard to Enterococcus species distribution, virulence factors and antibiotic susceptibility. Three methods (API, Multiplex sodA-PCR, 16S rRNA sequencing) were compared for Enterococcus species identification. Cloacal samples from 179 apparently healthy pigeons of 13 different flocks were tested. RESULTS Multiplex sodA-PCR and 16S rRNA gene sequencing showed almost perfect agreement in Enterococcus species identification. Isolates were identified as Enterococcus columbae (34.5%), Enterococcus hirae (20.7%), Enterococcus faecalis (11.7%), Enterococcus faecium (11.7%), Enterococcus gallinarum (9%), Enterococcus mundtii (4.8%), Enterococcus casseliflavus (3.4%), Enterococcus cecorum (2.1%), Enterococcus durans (2.1%). More Enterococcus species were found after the race season than before. The study showed differences between Enterococcus species in relation to 68.8% (22/32) biochemical parameters. Six out of seven virulence genes were detected: gelE (43.5%), asa1 (42.1%), efaA (30.3%), ace (30.3%), cylA (27.6%), and esp (9%). None of the isolates harboured hyl gene. Overall 15.2% of Enterococcus isolates produced gelatinase, but 66.7% gelE genes were silent. Enterococcus faecalis showed the most often efaA, ace and gelatinase activity than other enterococcal species. Nearly all isolates (93.1%) were resistant to at least one antibiotic. The most frequent resistance was to enrofloxacin (80%), doxycycline with teicoplanin (73.1%), erythromycin (49.7%). The study revealed significant differences between some enterococcal species in the antibiotic susceptibility to different antibiotics. Enterococcus columbae and E. cecorum showed significantly more frequent resistance to chloramphenicol than other enterococci. The presence of VRE (19.3%), HLGR (2.8%) and no LRE were found. Overall 30.3% of isolates were positive for vancomycin resistance genes, where vanC1 (E. gallinarum), vanC2-C3 (E. hirae, E. casseliflavus), vanB (E. columbae) predominated. CONCLUSIONS We conclude, that intestinal microbiota in racing pigeons is composed by 9 different Enterococcus species. Given that racing pigeons are kept in close contact with humans and backyard animals, combined with their long-distance flight abilities, they can serve as potential source of virulent and antibiotic resistant Enterococcus spp. in the environment.

中文翻译：

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赛鸽（Columba livia f。domestica）肠球菌的患病率，抗生素敏感性和毒力因子。

背景技术本研究旨在研究赛鸽的肠道菌群，包括肠球菌的种类分布，毒力因子和抗生素敏感性。比较了三种方法（API，Multiplex sodA-PCR，16S rRNA测序）来鉴定肠球菌。测试了来自13个不同群的179头显然健康的鸽子的泄殖腔样本。结果多重sodA-PCR和16S rRNA基因测序表明肠球菌的鉴定几乎完全一致。分离株为肠球菌（34.5％），平肠肠球菌（20.7％），粪肠球菌（11.7％），粪肠球菌（11.7％），鸡肠球菌（9％），芒氏肠球菌（4.8％），卡氏肠球菌（3.4） ％），盲肠肠球菌（2.1％），杜兰肠球菌（2.1％）。赛季结束后发现的肠球菌比以前多。该研究表明肠球菌物种之间在生化参数方面的差异为68.8％（22/32）。检测到七个毒力基因中的六个：gelE（43.5％），asa1（42.1％），efaA（30.3％），ace（30.3％），cylA（27.6％）和esp（9％）。分离株均未携带hyl基因。总共有15.2％的肠球菌产生明胶酶，但66.7％的gelE基因沉默。与其他肠球菌相比，粪肠球菌显示出最常见的efaA，ace和明胶酶活性。几乎所有分离株（93.1％）对至少一种抗生素都有抗药性。最常见的耐药是对恩诺沙星（80％），强力霉素和替考拉宁（73.1％），红霉素（49.7％）的耐药性。该研究揭示了某些肠球菌之间在对不同抗生素的敏感性方面存在显着差异。肠球菌和盲肠大肠杆菌比其他肠球菌对氯霉素的抗药性明显更高。发现有VRE（19.3％），HLGR（2.8％）和LRE。总体上，分离株的30.3％对万古霉素抗性基因呈阳性，其中vanC1（E. gallinarum），vanC2-C3（E. hirae，casseliflavus），vanB（E. columbae）占主导地位。结论我们得出结论，赛鸽的肠道菌群由9种不同的肠球菌组成。鉴于赛鸽与人类和后院动物保持紧密接触，并具有远距离飞行能力，因此它们可以作为潜在的强力和耐抗生素肠球菌来源。