Location: Produce Safety and Microbiology ResearchTitle: Whole-genome analyses of a new locus of enterocyte effacement-positive Shiga toxin-producing Escherichia coli O103:H2 strain isolated from cattle feces
Submitted to: Microbiology Resource Announcements
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2020
Publication Date: N/A
Interpretive Summary: Shiga toxin-producing E. coli (STEC) is one of the major foodborne pathogens that can cause several human diseases. STEC O103 is the second most prevalent pathotype next to STEC O157:H7 and recently associated with multiple foodborne outbreaks, primarily resulting from contamination of beef products in the United States. Cattle are the primary reservoir of STEC strains and have been contributing to food safety issues via fecal contamination. Here, we report the virulence genes associated with the genome of the STEC O103:H2 strain, RM13322, isolated from cattle feces through whole-genome sequencing. The STEC O103:H2 strain contains a total of 5,534 genes, of which some virulence genes, such as stx and eae genes, are able to contribute to severe illness, such as hemolytic uremic syndrome (HUS), after infection. The findings of this study provided valuable information on virulence factors for a STEC O103:H2 strain isolated from cattle feces.
Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) O103 serotype is one of the primary pathogenic contaminants of beef products, contributing to several foodborne outbreaks in recent years. Here, we report the complete genome sequence and the virulence factors of a STEC O103:H2 strain (RM13322) isolated from cattle feces to unveil the potential pathogenicity of this pathogen. The result indicated that this E. coli O103:H2 strain RM13322 contains a 5,622,341-bp chromosome and a 76,269-bp plasmid. The chromosome has an average GC content of 50.8% and encodes a total of 5,534 coding DNA sequences (CDSs), 22 rRNA, and 98 tRNAs. The strain harbors a 117,904-bp Stx1a prophage and a 71,689-bp locus of enterocyte effacement (LEE) pathogenicity island. Additionally, several non-LEE encoded Type III translocated virulence factors and adherence associated genes were present in the bacterial chromosome. Interestingly, IncFIB-type plasmid pRM13322 is a phage-like plasmid that contains phage-associated essential CDSs encoding functional proteins, such as structurally related proteins, lysis related-proteins and lytic-lysogenic switch related repressors. The findings of this study provide valuable insights into the virulence factors of STEC O103:H2 of bovine origin.