一株A型副鸡禽杆菌的分离与鉴定

Isolation and identification of a strain of Aviobacterium paragallinarum type A

对湖北省某规模化养鸡场中肿头肿脸病料进行病原菌分离,对分离菌株进行分子生物学、生化特性、血清型和耐药性鉴定,并测定了分离菌株基因组序列,通过动物回归试验验证菌株致病性。结果表明,从病料中分离出白色圆形、边缘光滑、半透明露珠样的菌落,革兰氏染色为阴性短杆菌,卫星试验中呈典型的“卫星”现象,分离菌株的16S rRNA与已报道的副鸡禽杆菌(Avibacterium paragallinarum)高度同源,血清型鉴定为A型;药敏试验结果显示分离株对甲氧苄胺嘧啶、林可霉素和阿米卡星耐药,对强力霉素、大观霉素等多种抗生素敏感;动物回归试验显示,分离菌株引起雏鸡典型的肿头肿脸症状,病理切片显示菌株造成雏鸡的肺脏、肝脏以及脾脏出现明显的病变。分离株二代全基因组测序结果显示分离株有53个耐药基因和121个毒力基因。

The bacteria were isolated from diseased materials with swollen heads and swollen faces in a large-scale chicken farm in Hubei province.The molecular biology,biochemical characteristics,serotype and drug resistance of the isolated strain were identified,and the genome sequence of the isolated strain was determined.The pathogenicity of the strain was verified through animal regression experiments.Results showed that white round,smooth edges,translucent dew-like colonies were isolated from the samples.The isolated strain was gram-negative bacterium,which showed a typical“satellite”pattern in satellite tests.The 16S rRNA sequence of isolated strain was highly homologous to reported sequence of Avibacterium paragallinarum.Its serotype was identified as type A.And the results of drug susceptibility tests showed that the isolate strain was resistant to trimethoprim,lincomycin and amikacin,while sensitive to various antibiotics such as doxycycline,spectinomycin.Animal regression experiments showed that the isolated strain caused typical swollen head and face symptoms in chicks.Pathological sections showed the strain caused significant lesions in the lungs,liver and spleen of chicks.The whole-genome sequence of isolated strain showed that it had 53 drug resistance genes and 121 virulence genes.