副猪嗜血杆菌的分离鉴定及16S rRNA序列分析

从云南某规模化养猪场病猪肺脏分离到1株革兰氏阴性小杆菌,经细菌生化鉴定、PCR鉴定和16S rRNA序列比对鉴定为副猪嗜血杆菌。抗生素药物敏感试验结果表明,分离菌株对四环素、红霉素、氯霉素、头孢噻吩高敏;对庆大霉素、氧氟沙星、诺氟沙星中敏;对磺胺甲唑耐药。16S rRNA分析结果表明,该分离株与GenBank中的Hps参考株AB078973(基因登录号)同源性为100%,将分离菌株鉴定为副猪嗜血杆菌。16S rRNA遗传进化关系表明,分离株与副猪嗜血杆菌3株血清5型参考株AB078972、AB078973、AB078974的16S rRNA序列位于一个分支上,遗传进化关系最近,它们之间的核苷酸同源性在99.0%~99.4%之间,初步鉴定为血清5型副猪嗜血杆菌,致病性试验结果表明,分离菌株对小白鼠有强致病性,命名为YN-1株。

Isolation, Identification of a Haemophilus parasuis and Analysis of 16S rRNA Gene

Gram negative bacilli was isolated from lung of sick pig in Large-scale pig farm,the bacilli was identified as Haemophilus parasuis by physiological and biochemical identification,PCR identification and 16S rRNA gene nucleotide BLAST.Antibiotics sensitivity test showed that the isolation strain was high sensitive to erythrocin,chloromycetin,cephalothin,etc.Low sensitive to gentamycin,ofloxacin,noroxin,and resistant to sulfamethoxazole.The analysis of 16S rRNA showed that the 16S rRNA sequence homology between the isolated strain and reference strain Haemophilus parasuis AB078973(GenBank accession number) was 100%.Phylogenetic tree of 16S rRNA showed that the isolated strain was situated on the same branch with 3 serotype 5 reference strains AB078972,AB078973 and AB078974,and the nucleotide homology between the isolated strain and the 3 reference train was 99.0% to 99.4%.Therefore,the isolated strain was identified as Haemophilus parasuis serotype 5.Pathogenicity test showed that the isolated strain was highly pathogenic to laboratory mice.The isolated Haemophilus parasuis strain was named YN-1 strain.