安徽部分地区动物源弯曲菌的分离鉴定及多位点序列分型

Isolation,identification and multilocus sequence typing of Campylobacter from animal source in Anhui province

【背景】弯曲菌是一种重要的食源性人兽共患病原菌,革兰氏阴性、微需氧、弯曲螺旋状。【目的】为了解安徽地区弯曲菌流行状况和分子遗传特征,对安徽6个不同地区动物源的弯曲菌进行分离鉴定,并研究分离株分子分型。【方法】通过形态学及培养特性观察、生化试验、PCR方法对菌株进行鉴定。以弯曲菌7个管家基因asp A、gln A、glt A、gly A、pgm、tkt和unc A为目的基因对分离株进行多位点序列分型,并制成遗传进化树。【结果】共分离到42株弯曲菌菌株,源自6个地区的分离株具有较为一致的形态特性和相似的生化特性。多位点序列分型结果显示,本研究中共获得32种ST型,共发现9种新的ST型(8190、8222、8223、8831、8833、8841、8832、8834和8843)和6个新的等位基因(gln A606、gln A607、glt A518、gly A680、pgm863和unc A541)。进化树结果显示,空肠弯曲菌与结肠弯曲菌遗传关系相差甚远,聚集归为两个大群,分别有5个分支和3个分支。【结论】安徽6个地区不同来源的空肠弯曲菌与结肠弯曲菌均有丰富的基因型,且没有明显优势的基因型。从遗传变异的角度来看,空肠弯曲菌复杂多样,结肠弯曲菌相对保守。

[Background] Campylobacter is a Gram-negative microaerobic bacterium. It is a major foodborne pathogen and causes human gastroenteritis worldwide. [Objective] This study was to isolate, identify and molecular type Campylobacter from animal in six different areas of Anhui province. [Methods] The strains were identified by morphological and culture characteristics, biochemical tests and PCR. Seven Campylobacter housekeeping genes including asp A, gln A, glt A, gly A, pgm, tkt and unc A were amplified by PCR and sequenced, and then the sequences of genes were analyzed using multilocus sequence typing（MLST） database and evolutionary tree. [Results] There were a total of 42 strains of Campylobacter were isolated from six areas. The isolates had more consistent morphological characteristics and similar biochemical properties. MLST results show that 32 sequence types, 9 new sequence types（including 8190, 8222, 8223, 8831, 8833, 8841, 8832, 8834 and 8843） and 6 new allelic profiles（including gln A606, gln A607, glt A518, gly A680, pgm863 and unc A541） were found. Evolutionary tree results show that C. jejuni and C. coli genetic relationship is very different and belong to two groups, which have five branches and three branches, respectively. [Conclusion] C. jejuni and C. coli have rich genotypes in Anhui province, and there is no obvious dominant genotype. From the perspective of genetic variation, C. jejuni is more complex and diverse, while C. coli is relatively conservative.