一株副溶血弧菌D3112致病性和抗药性的表征

副溶血弧菌广泛分布于海洋环境中,虽然大多数环境菌株并非致病菌,但它们常常携有毒力基因,从而具有潜在的致病性。本文从黄海(山东青岛)海水中分离到一株副溶血弧菌D3112,对其进行了全基因组测序、溶血实验和人工感染实验等。基因组测序分析发现D3112并不含有副溶血弧菌的致病性标志溶血素基因tdh和trh,这与PCR检测结果一致,但含有其他溶血素基因以及多种毒力相关基因。生物学实验显示,该菌可产生明显的溶血现象,而且具有蛋白酶、明胶酶、脂酶和淀粉酶活性,但是缺少卵磷脂酶活性。人工感染实验表明副溶血弧菌D3112具有致病性,感染斑马鱼的半致死剂量约为5×105CFU。药物敏感实验证明了D3112具有多重耐药性。本文对海洋环境中的副溶血弧菌D3112同时开展了基因型和表型研究,为准确评价环境细菌的潜在致病性提供了有用的数据信息。

Characterization of pathogenicity and drug resistance in Vibrio parahaemolyticus D3112

Vibrio parahaemolyticus is widely distributed in the marine environment. Although the majority of environmental strains are not clinically pathogenic, they often contain virulence-related genes that make them potential pathogens. In the present experiment, the whole genome of V. parahaemolyticus strain D3112 isolated from the seawater of the Yellow Sea (Shandong, Qingdao) was sequenced and analyzed. The genes tdh and trh, which encode hemolysins and are routinely used as molecular markers for indicating pathogenicity in V. parahaemolyticus, were absent in the genome of D3112. Nevertheless, D3112 contained other hemolysin genes as well as an array of genes related to virulence. D3112 also exhibited obvious hemolysis activity. Extracellular enzyme activity assays revealed protease, gelatinase, lipase, and amylase activities, except lecithinase activity. Artificial infection experiment demonstrated that the strain had potential pathogenicity, with an LD₅₀ value of 5×10⁵ CFU for zebrafish. In addition, antibiotic sensitivity experiments revealed that the strain was multidrug-resistant. To summarize, the present study performed both genome analysis and phenotypic experiments using D3112, providing useful information for accurately diagnosing the pathogenic potential of environmental strains of V. parahaemolyticus.