Abstract
Shiga toxin–producing Escherichia coli (STEC) O80:H2 has emerged in Europe as a cause of hemolytic uremic syndrome associated with bacteremia. STEC O80:H2 harbors the mosaic plasmid pR444_A, which combines several virulence genes, including hlyF and antimicrobial resistance genes. pR444_A is found in some extraintestinal pathogenic E. coli (ExPEC) strains. We identified and characterized 53 STEC strains with ExPEC-associated virulence genes isolated in Italy and the Netherlands during 2000–2019. The isolates belong to 2 major populations: 1 belongs to sequence type 301 and harbors diverse stx2 subtypes, the intimin variant eae-ξ, and pO157-like and pR444_A plasmids; 1 consists of strains belonging to various sequence types, some of which lack the pO157 plasmid, the locus of enterocyte effacement, and the antimicrobial resistance–encoding region. Our results showed that STEC strains harboring ExPEC-associated virulence genes can include multiple serotypes and that the pR444_A plasmid can be acquired and mobilized by STEC strains.
Highlights
Shiga toxin–producing Escherichia coli (STEC) O80:H2 has emerged in Europe as a cause of hemolytic uremic syndrome associated with bacteremia
We investigated 500 STEC strains isolated in Italy during 2000–2019 by the National Reference Laboratory for E. coli as part of the national surveillance program for hemolytic uremic syndrome (HUS) and samples isolated from animal and food products in the framework of the official control activity
Circulating STEC Strains with extraintestinal pathogenic E. coli (ExPEC)-Associated Virulence Genes The analyzed sequences had an average coverage of 118× and the assembled contigs an N50 average of 94,346 bp (Appendix 1 Table 1, https://wwwnc.cdc. gov/EID/article/27/3/20-3110-App1.pdf)
Summary
Shiga toxin–producing Escherichia coli (STEC) O80:H2 has emerged in Europe as a cause of hemolytic uremic syndrome associated with bacteremia. STEC O80 strains possess virulence genes carried by mobile genetic elements associated with intestinal and extraintestinal pathogenic E. coli [14]. Such strains harbor the LEE locus, the stx gene, and a plasmid resembling the pO157 first described in STEC O157 serogroup carrying virulence genes including the enterohemolysin encoding gene (ehxA) [25,26]. These strains often possess a peculiar mosaic plasmid called pR444_A. The hlyF gene is associated with an increased production of outer membrane vesicles, possibly contributing to the release of cytolethal distending toxin and other chemicals involved in ExPEC pathogenesis [32]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
