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

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.