一株21型猪链球菌的分离鉴定及生物学特性研究

Isolation, identification and biological characteristics of a strain of Streptococcus suis type 21

为了确定保定市某猪场发病猪感染的病原并了解该病原的生物学特性,试验对采集的肺脏组织病料进行病原菌的分离,采用荧光定量PCR、生化试验对分离菌株进行鉴定,并对分离菌株进行血清型鉴定、药敏试验、耐药基因和毒力基因检测。结果表明:分离到一株病原菌,将其命名为BDS21。经鉴定该分离菌株为21型猪链球菌。BDS21菌株对头孢曲松钠、阿奇霉素敏感,对氨苄西林、卡那霉素、左氧氟沙星中介,对头孢噻肟、四环素、林可霉素、环丙沙星耐药;检出tetM和ermA 2种耐药基因,gapdh、sly、fbps、gdh、orf2 5种毒力基因。说明该养殖场发病猪感染的病原可能是21型猪链球菌,防控首选药物为头孢类和大环内酯类抗生素。

In order to determine the pathogen and understand the biological characteristics of the pathogen in a pig farm in Baoding City, the experiment was conducted to isolate the pathogenic bacteria from the collected lung tissue material. The isolates were identified by fluorescent quantitative PCR and biochemical tests, and the isolates were subjected to serotype identification, drug sensitivity tests, drug resistance genes and virulence gene detection. The results showed that a pathogenic strain was isolated and named as BDS21. The strain was identified as Streptococcus suis type 21. Strain BDS21 was sensitive to ceftriaxone sodium and azithromycin, moderately resistant to ampicillin, kanamycin and levofloxacin, and resistant to cefotaxime, tetracycline, lincomycin and ciprofloxacin. Two drug resistance genes, tetM and ermA, were detected;five virulence genes, gapdh, sly, fbps, gdh, and orf2, were detected. The results suggested that the pathogen of the infected pigs in this farm was probably Streptococcus suis type 21, and the drugs of choice for the prevention and control of Streptococcus suis were cephalosporins and macrolide antibiotics.