Emergence of Escherichia coli encoding Shiga toxin 2f in human Shiga toxin-producing E. coli (STEC) infections in the Netherlands, January 2008 to December 2011

Abstract

The Shiga toxins of Shiga toxin-producing Escherichia coli (STEC) can be divided into Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2) with several sub-variants. Variant Stx 2f is one of the latest described, but has been rarely associated with symptomatic human infections. In the enhanced STEC surveillance in the Netherlands, 198 STEC O157 cases and 351 STEC non-O157 cases, including 87 stx 2f STEC isolates, were reported between 2008 and 2011. Most stx 2f strains belonged to the serogroups O63:H6 (n=47, 54%), O113:H6 (n=12, 14%) and O125:H6 (n=12, 14%). Of the 87 stx 2f isolates, 84 (97%) harboured the E. coli attaching and effacing (eae) gene, but not the enterohaemorrhagic E. coli haemolysin (hly) gene. stx 2f STEC infections show milder symptoms and a less severe clinical course than STEC O157 infections. Almost all infections with stx 2f (n=83, 95%) occurred between June and December, compared to 170/198 (86%) of STEC O157 and 173/264 (66%) of other STEC non-O157. stx 2f STEC infections in the Netherlands are more common than anticipated, and form a distinct group within STEC with regard to virulence genes and the relatively mild disease.

Isolation and Characterization of an <i>Escherichia albertii</i> Strain Producing Three Different Toxins from a Child with Diarrhea

“…The CDTs identified in strain P2660 were CDT-I and CDT-II; however, the pathogenicity of the strain might depend on the production of CDT-I, CDT-II, and Stx2f as well as the intimin (an adhesin) encoded by eae. Although there is limited epidemiological information regarding the isolation of stx2f gene-positive E. albertii in human patients (18,23,24), it was recently reported that stx2f gene-positive E. coli accounted for 13% and 16% of all STEC clinical isolates in Belgium and the Netherlands, respectively (32,33), suggesting that stx2f gene-positive E. coli may be an emerging pathogen. Patients infected with stx2f gene-positive E. coli showed milder symptoms and a less severe clinical course than those infected with STEC serogroup O157 (33).…”

“…Although there is limited epidemiological information regarding the isolation of stx2f gene-positive E. albertii in human patients (18,23,24), it was recently reported that stx2f gene-positive E. coli accounted for 13% and 16% of all STEC clinical isolates in Belgium and the Netherlands, respectively (32,33), suggesting that stx2f gene-positive E. coli may be an emerging pathogen. Patients infected with stx2f gene-positive E. coli showed milder symptoms and a less severe clinical course than those infected with STEC serogroup O157 (33). Indeed, strain P2660 was isolated from a child with watery diarrhea, which is not as severe as the diseases caused by STEC O157 infection, such as hemorrhagic colitis and hemolytic uremic syndrome (HUS).…”

Prevalence of Shiga Toxin-Producing and Enteropathogenic Escherichia coli in Wild and Pet Birds in Iran

“…Although all STEC strains in this study only possessed the stx2f subtype, the public health significance of these strains should not be overlooked, because the stx2f+ E. coli strains have also been isolated from humans with diarrhea (Prager et al, 2009;Isobe et al, 2004). Recent evidences also show the particular importance of stx2f-STEC as an emerging unnoticed human pathogen (Friesema et al, 2014). Since the stx2f is not easily identified using most routine diagnostic procedures (except using appropriate general primers), all of the eae-harboring strains from birds should be checked for the presence of this particular Shiga toxin subtype.…”

Shiga Toxin 2a in Escherichia albertii

“…STEC harboring eae and stx 2a are considered highly virulent and have the ability to induce life-threatening hemolytic uremic syndrome (HUS) in infected patients (10). In contrast, STEC harboring stx 2f are associated with milder symptoms (11) and have, to our knowledge, never previously been detected in HUS patients. The patient infected with stx 2a -positive E. albertii was 48 years old, had bloody diarrhea, and was infected in Norway (Table 1).…”