Kikuchi Ken    Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine    Position   Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Diversity and microevolution of CRISPR loci in Helicobacter cinaedi.
Journal	Formal name：PLoS ONE ISSN code：19326203
Domestic / Foregin	Foregin
Volume, Issue, Page	12(10),pp.e0186241
Author and coauthor	Junko Tomida, Yuji Morita, Keigo Shibayama, Ken Kikuchi, Tomohiro Sawa, Takaaki Akaike, Yoshiaki Kawamura
Publication date	2017/10
Summary	Helicobacter cinaedi is associated with nosocomial infections. The CRISPR-Cas system provides adaptive immunity against foreign genetic elements. We investigated the CRISPR-Cas system in H. cinaedi to assess the potential of the CRISPR-based microevolution of H. cinaedi strains. A genotyping method based on CRISPR spacer organization was carried out using 42 H. cinaedi strains. The results of sequence analysis showed that the H. cinaedi strains used in this study had two CRISPR loci (CRISPR1 and CRISPR2). The lengths of the consensus direct repeat sequences in CRISPR1 and CRISPR2 were both 36 bp-long, and 224 spacers were found in the 42 H. cinaedi strains. Analysis of the organization and sequence similarity of the spacers of the H. cinaedi strains showed that CRISPR arrays could be divided into 7 different genotypes. Each genotype had a different ancestral spacer, and spacer acquisition/deletion events occurred while isolates were spreading. Spacer polymorphisms of conserved arrays across the strains were instrumental for differentiating closely-related strains collected from the same hospital. MLST had little variability, while the CRISPR sequences showed remarkable diversity. Our data revealed the structural features of H. cinaedi CRISPR loci for the first time. CRISPR sequences constitute a valuable basis for genotyping, provide insights into the divergence and relatedness between closely-related strains, and reflect the microevolutionary process of H. cinaedi.
DOI	https://doi.org/10.1371/journal.pone.0186241