title: Association of clustered regularly interspaced short palindromic repeat (CRISPR) elements with specific serotypes and virulence potential of shiga toxin-producing Escherichia coli.
abstract: Shiga toxin-producing Escherichia coli (STEC) strains (n = 194) representing 43 serotypes and E. coli K-12 were examined for clustered regularly interspaced short palindromic repeat (CRISPR) arrays to study genetic relatedness among STEC serotypes. A subset of the strains (n = 81) was further analyzed for subtype I-E cas and virulence genes to determine a possible association of CRISPR elements with potential virulence. Four types of CRISPR arrays were identified. CRISPR1 and CRISPR2 were present in all strains tested; 1 strain also had both CRISPR3 and CRISPR4, whereas 193 strains displayed a short, combined array, CRISPR3-4. A total of 3,353 spacers were identified, representing 528 distinct spacers. The average length of a spacer was 32 bp. Approximately one-half of the spacers (54%) were unique and found mostly in strains of less common serotypes. Overall, CRISPR spacer contents correlated well with STEC serotypes, and identical arrays were shared between strains with the same H type (O26:H11, O103:H11, and O111:H11). There was no association identified between the presence of subtype I-E cas and virulence genes, but the total number of spacers had a negative correlation with potential pathogenicity (P < 0.05). Fewer spacers were found in strains that had a greater probability of causing outbreaks and disease than in those with lower virulence potential (P < 0.05). The relationship between the CRISPR-cas system and potential virulence needs to be determined on a broader scale, and the biological link will need to be established.
authors: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA.
authors: Magaly
authors: M
authors: Toro
authors: Guojie
authors: G
authors: Cao
authors: Wenting
authors: W
authors: Ju
authors: Marc
authors: M
authors: Allard
authors: Rodolphe
authors: R
authors: Barrangou
authors: Shaohua
authors: S
authors: Zhao
authors: Eric
authors: E
authors: Brown
authors: Jianghong
authors: J
authors: Meng
mesh_terms: D016000:Cluster Analysis; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005838:Genotype; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D012703:Serotyping; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors