Polymorphism of Type I-F CRISPR/Cas system in Escherichia coli of phylogenetic group B2 and its application in genotyping.

Polymorphism of Type I-F CRISPR/Cas system in Escherichia coli of phylogenetic group B2 and its application in genotyping. Infect Genet Evol. 2019 Jun 10;:103916 Authors: Long J, Xu Y, Ou L, Yang H, Xi Y, Chen S, Duan G Abstract E. coli of phylogenetic group B2 is responsible for many extraintestinal infections, posing a great threat to health. The relatively polymorphic nature of CRISPR in phylogenetically related E. coli strains makes them potential markers for bacterial typing and evolutionary studies. In the current work, we investigated the occurrence and diversity of CRISPR/Cas system and explored its potential for genotyping. Type I-F CRISPR/Cas systems were found in 413 of 1190 strains of E. coli and exhibited the clustering within certain CCs and STs. And CRISPR spacer contents correlated well with MLST types. The divergence analysis of CRISPR showed stronger discriminatory power than MLST, and CRISPR polymorphism was instrumental for differentiating highly closely related strains. The timeline of spacer acquisition and deletion provided important information for inferring the evolution model between distinct serotypes. Identical spacer sequences were shared by strains with the same H-antigen type but not strains with the same O-antigen type. The homology between spacers and antibiotic-resistant plasmids demonstrated the role of Type I-F system in limiting the acquisition of antimicrobial resistance. Collectively, our data p...
Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Tags: Infect Genet Evol Source Type: research