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. 2020 Feb 1;12(2):3850-3856. doi: 10.1093/gbe/evaa014.
Arcobacter species are recovered from a wide variety of sources, including animals, food, and both fresh and marine waters. Several Arcobacter species have also been recovered from human clinical samples and are thus associated tentatively with food- and water-borne human illnesses. Genome sequencing of the poultry isolate Arcobacter cibarius H743 and the Arcobacter acticola, Arcobacter pacificus, and Arcobacter porcinus type strains identified a large number and variety of insertion sequences. This study presents an analysis of these A. acticola, A. cibarius, A. pacificus, and A. porcinus IS elements. The four genomes sequenced here contain 276 complete and degenerate IS elements, representing 13 of the current 29 prokaryotic IS element families. Expansion of the analysis to include 15 other previously sequenced Arcobacter spp. added 73 complete and degenerate IS elements. Several of these IS elements were identified in two or more Arcobacter species, suggesting movement by horizontal gene transfer between the arcobacters. These IS elements are putatively associated with intragenomic deletions and inversions, and tentative movement of antimicrobial resistance genes. The A. cibarius strain H743 megaplasmid contains multiple IS elements common to the chromosome and, unusually, a complete ribosomal RNA locus, indicating that larger scale genomic rearrangements, potentially resulting from IS element-mediated megaplasmid cointegration and resolution may be occurring within A. cibarius and possibly other arcobacters. The presence of such a large and varied suite of mobile elements could have profound effects on Arcobacter biology and evolution.
弯曲杆菌物种存在于多种来源中，包括动物、食物以及淡水和海水。一些弯曲杆菌物种也从人类临床样本中回收，因此与食源性和水源性人类疾病有一定的关联。对家禽分离株弯曲杆菌 H743 和弯曲杆菌活跃亚种、太平洋弯曲杆菌和猪弯曲杆菌的基因组测序确定了大量不同的插入序列。本研究对这些弯曲杆菌活跃亚种、弯曲杆菌 H743、太平洋弯曲杆菌和猪弯曲杆菌的 IS 元件进行了分析。这里测序的四个基因组包含 276 个完整和退化的 IS 元件，代表了目前 29 个原核 IS 元件家族中的 13 个。将分析扩展到包括其他 15 个以前测序的弯曲杆菌种，增加了 73 个完整和退化的 IS 元件。其中一些 IS 元件在两个或更多弯曲杆菌种中被识别，表明弧菌之间通过水平基因转移发生了移动。这些 IS 元件可能与基因组内缺失和倒位以及抗生素耐药基因的移动有关。弯曲杆菌 H743 大质粒包含与染色体共同的多个 IS 元件，而且不同寻常的是，还有一个完整的核糖体 RNA 基因座，这表明更大规模的基因组重排，可能是由 IS 元件介导的大质粒共整合和分辨率的变化，可能正在弯曲杆菌种内发生，并且可能在其他弧菌中也在发生。如此大量和多样的可移动元件的存在可能对弯曲杆菌的生物学和进化产生深远的影响。
