Miller William G, Yee Emma, Chapman Mary H, Bono James L
Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, California.
Meat Safety and Quality Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Clay Center, Nebraska.
Genome Biol Evol. 2017 Jun 1;9(6):1513-1518. doi: 10.1093/gbe/evx112.
Campylobacter sputorum is a nonthermotolerant campylobacter that is primarily isolated from food animals such as cattle and sheep. C. sputorum is also infrequently associated with human illness. Based on catalase and urease activity, three biovars are currently recognized within C. sputorum: bv. sputorum (catalase negative, urease negative), bv. fecalis (catalase positive, urease negative), and bv. paraureolyticus (catalase negative, urease positive). A multi-locus sequence typing (MLST) method was recently constructed for C. sputorum. MLST typing of several cattle-associated C. sputorum isolates suggested that they are members of a divergent C. sputorum clade. Although catalase positive, and thus technically bv. fecalis, the taxonomic position of these strains could not be determined solely by MLST. To further characterize C. sputorum, the genomes of four strains, representing all three biovars and the divergent clade, were sequenced to completion. Here we present a comparative genomic analysis of the four C. sputorum genomes. This analysis indicates that the three biovars and the cattle-associated strains are highly related at the genome level with similarities in gene content. Furthermore, the four genomes are strongly syntenic with one or two minor inversions. However, substantial differences in gene content were observed among the three biovars. Finally, although the strain representing the cattle-associated isolates was shown to be C. sputorum, it is possible that this strain is a member of a novel C. sputorum subspecies; thus, these cattle-associated strains may form a second taxon within C. sputorum.
黏液弯曲菌是一种不耐热的弯曲菌，主要从牛和羊等食用动物中分离得到。黏液弯曲菌也很少与人类疾病相关。根据过氧化氢酶和尿素酶活性，目前在黏液弯曲菌中识别出三个生物变种：变种sputorum（过氧化氢酶阴性，尿素酶阴性）、变种fecalis（过氧化氢酶阳性，尿素酶阴性）和变种paraureolyticus（过氧化氢酶阴性，尿素酶阳性）。最近为黏液弯曲菌构建了一种多位点序列分型（MLST）方法。对几株与牛相关的黏液弯曲菌分离株进行的MLST分型表明，它们是一个不同的黏液弯曲菌进化枝的成员。尽管这些菌株过氧化氢酶呈阳性，因此在技术上属于变种fecalis，但仅通过MLST无法确定这些菌株的分类地位。为了进一步表征黏液弯曲菌，对代表所有三个生物变种和不同进化枝的四株菌株的基因组进行了全序列测定。在此，我们展示了对这四个黏液弯曲菌基因组的比较基因组分析。该分析表明，这三个生物变种和与牛相关的菌株在基因组水平上高度相关，基因含量相似。此外，这四个基因组具有很强的共线性，只有一两个小的倒位。然而，在这三个生物变种之间观察到基因含量存在显著差异。最后，尽管代表与牛相关的分离株的菌株被证明是黏液弯曲菌，但该菌株有可能是一个新的黏液弯曲菌亚种的成员；因此，这些与牛相关的菌株可能在黏液弯曲菌中形成第二个分类单元。
