一株尿素酶阴性产气巴氏杆菌的分离鉴定及生物学特性分析

Isolation and biological characterization of a urease-negative Pasteurella aerogenes

本研究从猪流产胎儿中分离到一株形似产气巴氏杆菌菌株并命名为ZY14013,对其进行生化鉴定、16S rDNA序列分析和药物敏感性分析。生化鉴定结果表明,ZY14013除尿素酶阴性外,其它生化特征与产气巴氏杆菌模式菌株ATCC 27883以及其它分离株具有相似生化特征。遗传进化分析表明ZY14013与ATCC 2788以及16株现存分离株16S rDNA核苷酸同源性分别为99.2%和99.6%~99.9%,在进化树中形成同一个群。药敏试验表明,分离株ZY14013对青霉素、氟苯尼考和头孢类抗生素敏感,对链霉素、卡那霉素、庆大霉素、氯霉素和氧氟沙星耐药。本研究首次证实了猪产气巴氏杆菌感染在中国大陆的存在,同时,本研究在世界首次分离到尿素酶阴性产气巴氏杆菌,丰富了产气巴氏杆菌的生化特征,为研究尿素酶在产气巴氏杆菌致病性中的作用提供了自然突变体。

In the present study, a predominant bacterium was isolated from aborted swine fetus. The identification showed that the isolate had the similar biochemical characteristics to the Pasteurella aerogenes strain ATCC 27883, except for urease-negative. The bacteria was further identified as P.aerogenes by 16S rDNA sequence analysis, which shared 99.2% and 99.6%-99.9% similarity with ATCC 27883 and the 16 P.aerogenes reference strains, respectively, and clustered together with them to form a highly related branch in the phylogenetic tree. Antibiotics susceptibility test showed that the isolate was sensitive to penicillin, florfenicol and cephalosporin antibiotics, but resistance to streptomycin, kanamycine, gentamicin, chloromycetin and ofloxacin. This study confirmed that the presence of P.aerogenes infection in swine in the mainland of China. It is also the first report of urease-negative P.aerogenes, this finding might provide new insights into the biochemical characteristics of P.aerogenes and help in evaluating the role of urease in the virulence of the bacteria.