川西地区鸡滑液囊支原体分离株的部分生物学特性及其VlhA基因遗传进化分析

为了解鸡滑液囊支原体(MS)在川西地区的感染情况,本研究采集15个肉鸡场疑似MS感染的病鸡咽拭子、跗关节和胸部滑液囊样本共75份,对经PCR检测为阳性的样本进行MS分离,并对分离株的主要生物学特性进行研究,以及对分离株的VlhA基因进行遗传进化分析。结果显示,75份样本MS PCR阳性检出率为41.33%(31/75),11个鸡场感染该病,场阳性率为73.33%(11/15);但仅从其中3个鸡场分离到9株MS,分离株菌落与菌体形态与已知MS培养特性相符,各分离株培养浓度为10~4CCU/mL^10~6CCU/mL,分离株以5×10~5CCU接种7日龄SPF鸡胚,鸡胚于接种后7 d^9 d死亡,且分离回收到接种菌株;9株MS分离株VlhA基因的同源性为86.1%~99.9%,与参考株同源性为86.2%~95.4%,其中分离自同一鸡场的7株MS VlhA基因同源性为96.4%~99.9%;分离株VlhA基因遗传进化分析显示,其中分离自两个不同鸡场的两株MS与国内流行株的亲缘关系最近,而分离自另一鸡场的7株MS与中东地区分离的3株MS亲缘关系较近,表明MS在川西地区肉鸡场呈高感染率,MS VlhA基因变异较大。本研究为川西地区MS的进一步研究提供了基础材料和科学依据。

Partial biological charicteristics of Mycoplasma synoviae isolates from western Sichuan analysis of it VIhA gene

To underst and the infection situation of Mycoplasma synoviae(MS)in western Sichuan,a total of 75 samples of pharyngeal swab,tarsus joint and synovial sac of diseased chickens suspected to be infected with MS were collected from 15 broiler farms in western Sichuan,the samples tested positive by PCR were used to isolate MS,further the basic biological characteristics and the VlhA gene of the MS isolates were analyzed.The results showed that the PCR positive rate of MS in 75 samples was 41.33%(31/75),and 11 out of 15 farms were PCR positive.However,only 9 MS strains were isolated from 3 farms,and the culture characteristics,colony and thallus morphology of isolates were consistent with those of known MS.The cultured concentrations of the MS isolates were from 10~4 to 10~6 CCU per milliliter.One of the isolates was inoculated with 5×10~5 CCU into 7-day-old SPF embryonated chicken eggs,which died 7d-9d after inoculation,and the inoculated strain was isolated and recovered.The VlhA gene homology of the 9 MS isolates was 86.1%-99.9%,while it ranged 86.2%-95.4% compared to 1 MS reference strain,and that of 7 MS isolates from the same farm was 96.4%-99.9%. Genetic evolutionary analysis of the isolates’ Vlh A gene showed that the two isolates from two different farms were most closely related to the domestic prevalent strains, and the other 7 MS isolates isolated from the same farm were relatively close to the 3 MS isolates isolated from the Middle East. This research showed a high MS infection rate in broiler farms in western Sichuan and a high variation within Vlh A gene of MS, which provide basic materials and lay the foundation for further research the MS in western Sichuan.