Version June 2024
| Shiga toxin genotype* | Risk for HUS? | Representative STEC serogroups or serotypes¶ | Usual appearance of diarrhea | |
| Stx (stx) 1 | Stx (stx) 2 | |||
| + | + | High | E. coli O26Δ, O111◊, sorbitol nonfermenting O157:H7 and O157:HNM§ | Visibly bloody |
| – | + | High | E. coli O80, O104¥, O121, sorbitol nonfermenting O157:H7 and O157:HNM§, and sorbitol fermenting O157:HNM‡ | Visibly bloody |
| + | – | Minimal or no | E. coli O26Δ, O103, O111◊ | Non-bloody |
STEC: Shiga-toxin-producing E. coli; HUS: hemolytic-uremic syndrome.
* STEC that produce Shiga toxin 2 are much more frequently associated with severe human disease (bloody diarrhea and HUS) than those that produce only Shiga toxin 1.
¶ Serotypes designate the O (somatic) and the H (flagellar) antigens. Serogroups designate only the O antigen, which is the lipopolysaccharide side chain.
Δ European STEC O26 contain genes encoding Shiga toxins 1 and 2 and are considered high risk and are a leading cause of HUS. North American STEC O26 generally produce Shiga toxin 1 but not Shiga toxin 2. They are isolated from patients with bloody diarrhea at similar frequencies to those with nonbloody diarrhea but are almost never associated with HUS.
◊ North American STEC O111 usually produce Stx 1 but not Stx 2 but, despite lacking a gene encoding Stx 2, can be a cause of bloody diarrhea. A subset of STEC O111 contain both toxin genes and can also cause HUS.
§ Occasionally, a laboratory will report that a sorbitol nonfermenting E. coli O157 is nonmotile, so the H antigen cannot be determined. These STEC should be considered equivalent to classic high-risk sorbitol-fermenting E. coli O157:H7 in virulence, even if the toxin genotype is not provided.
¥ This serogroup caused a massive outbreak in Germany and neighboring countries in 2011 but has not persisted as a major problem. It shares many features with enteroaggregative E. coli.
‡ This sorbitol fermenting nonmotile E. coli O157 is also designated E. coli O157:H–. It is recovered mostly in Germany and central Europe and is at least as virulent as E. coli O157:H7.آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
