鸭源鸡杆菌的分离鉴定及其全基因组序列分析

Isolation, identification and whole-genome sequencing of Gallibacterium anatis from chicken

摘要:

【背景】鸭源鸡杆菌作为一种条件致病菌能引起家禽卵巢炎、输卵管炎和腹膜炎等疾病，严重威胁养殖业的发展。【目的】四川某养鸡场送检了一批疑似感染鸭源鸡杆菌的病死鸡，为探究其感染机制与防治方法，对该菌进行分离鉴定及全基因组测序分析。【方法】从病料中分离并纯化细菌，再依次进行生化试验、16S rRNA基因序列分析和药敏试验，同时通过全基因组测序对其进行物种分型与毒力、耐药等基因功能注释及遗传进化分析。【结果】该分离菌被鉴定为鸭源鸡杆菌，菌株命名为TS0001，药敏试验显示其仅对硝基呋喃类和少数β-内酰胺类药物敏感，对部分β-内酰胺类、氯霉素、部分氨基糖苷类、大环内酯类、四环素类和磺胺类药物具有耐药性。全基因组序列长度为2 626 722 bp，蛋白质编码基因功能注释显示其有较强的自我加工修饰能力，全基因组注释到83个与毒力因子和耐药性相关的基因，包含4个前噬菌体区域。序列类型分析结果显示，该菌株为ST69型，而且管家基因联合建树表明其与墨西哥普通家鸡分离株7990一致性最高。【结论】本研究为鸭源鸡杆菌的感染机制与防治研究提供了参考，丰富了后续研究的分子生物学背景。

关键词:鸡;鸭源鸡杆菌;全基因组序列分析;致病性;耐药性

Abstract:

[Background] As an opportunistic pathogen, Gallibacterium anatis can cause poultry diseases such as ovaritis, salpingitis and peritonitis, which seriously threatens the development of poultry industry. [Objective] A shipment of chickens, died from a suspected G. anatis infection, was sent from a hennery in Sichuan. In order to explore the infection mechanism, prevention and treatment of G. anatis, we isolated and identified the bacterium and analyzed its whole genome sequence. [Methods] The bacterium was isolated and purified from the sample, followed by biochemical test, 16S rRNA gene sequence analysis, and drug sensitivity test. The whole-genome sequencing was carried out for species typing, annotation of virulence- and drug resistance-associated genes and phylogenetic analysis. [Results] The isolate was identified as G. anatis and named TS0001. Drug sensitivity test showed that the strain was sensitive to itrofurans and a few β-lactamines and resistant to some β-lactamines, chloramphenicol, some aminoglycosides, macrolides, tetracyclines and sulfonamides. The strain had a whole genome of 2 626 722 bp, and gene function annotation showed that it had strong self-modification capacity. A total of 83 genes related to virulence factors and drug resistance were annotated throughout the whole genome, and four prophage regions were predicted. The strain belonged to the sequence type ST69, and the phylogenetic tree constructed based on housekeeping genes demonstrated that it had the highest homology with the isolate 7990 from Mexican Gallus domesticus. [Conclusion] This study provides a reference for the research on the infection mechanism and prevention of G. anatis and enriches the molecular biological background for subsequent studies.

Key words:chicken;Gallibacterium anatis;genome sequence analysis;pathogenicity;drug resistance