昆明越冬红嘴鸥粪便潜在病原细菌及耐药基因与毒力因子组成

Potential pathogenic bacteria, antibiotic resistance genes, and virulence factors from the feces of Chroicocephalus ridibundus overwintering in Kunming

摘要:

【背景】昆明越冬红嘴鸥数量庞大且常与人近距离接触，其粪便细菌对人们有无感染威胁一直是关注焦点之一。【目的】探究红嘴鸥粪便中存在的潜在病原细菌及耐药表型、耐药基因与毒力因子。【方法】纯培养法分离鉴定粪便中的细菌，并对其中的部分病原细菌进行耐药表型分析；宏基因组测序检测红嘴鸥粪便样本中的潜在病原细菌以及耐药和毒力因子。【结果】纯培养分离发现红嘴鸥粪便中优势潜在病原细菌为粪肠球菌(Enterococcus faecalis)、威隆气单胞菌(Aeromonas veronii)、福氏志贺菌(Shigella flexneri)等；免培养方法检测到更多潜在病原细菌种，优势种为大肠埃希菌(Escherichia coli)、阿尔伯蒂埃希菌(Escherichia albertii)、屎肠球菌(Enterococcus faecium)等，但这些也是人和动物肠道常见菌种；红嘴鸥粪便和滇池水中部分纯培养潜在病原细菌耐药表型不严重，但免培养检测到丰富的耐药与毒力因子，关联分析发现其来源菌种广，并不局限于病原细菌种，不过相似度覆盖度高的耐药基因中并未见临床关注耐药基因；此外，红嘴鸥粪便和滇池水中许多病原细菌所在属耐药基因含量相关性高。【结论】红嘴鸥粪便中未分离检测到二类病原细菌，也未发现临床常见病原细菌种同时具有临床关注的耐药情况，推测其粪便菌群对免疫力正常人群无感染威胁。

Abstract:

[Background] A large number of black-headed gulls (Chroicocephalus ridibundus) overwinter in Kunming and have close contact with people. Whether their fecal bacteria can be a source of infections or not arouses public concern. [Objective] To explore the potential pathogenic bacteria, antibiotic resistance genes (ARGs), and virulence factors (VFs) in the feces of C. ridibundus. [Methods] Firstly, the bacteria in the feces were isolated and identified, and the antibiotic resistance of some potential pathogens was examined. Secondly, metagenomic sequencing was employed to detect the potential pathogens, ARGs, and VFs in the feces. [Results] Enterococcus faecalis, Aeromonas veronii, and Shigella flexneri were the main potential pathogenic bacteria detected by the isolation method, and Escherichia coli, Escherichia albertii, and Enterococcus faecium were the main potential pathogenic bacteria detected by metagenomic sequencing. These bacteria were frequently detected in the intestines of other animals and humans. Some isolated potential pathogenic bacteria were resistant to few antibiotics. The ARGs and VFs detected through metagenomic sequencing were abundant and had rich sources in addition to potential pathogenic bacteria. However, the ARGs receiving clinical concerns were not detected with high identity and coverage. In addition, some potential pathogenic bacterial genera and ARGs had high associations between the feces and the water in the Dianchi Lake. [Conclusion] No pathogenic bacteria belonging to the risk group II (China) or the ARGs arousing clinical concern were detected in the feces of C. ridibundus. Therefore, we conclude that the bacteria from the feces of C. ridibundus do not pose an infection threat to healthy people.