Nontoxigenic sorbitol-fermenting Escherichia coli O157:H- associated with a family outbreak of diarrhoea.
A recent study from Germany reported the isolation of E. coli O157:H7/H- from patients with non-bloody diarrhoea and hemolytic uremic syndrome, questioning the role of Shiga toxin as the main trait of virulence for human disease. We isolated 6 sorbitol-fermenting E. coli O157:H- strains that do not contain Shiga toxin genes. The isolates originated from an outbreak (3 patients, 3 asymptomatic contacts) of non-bloody diarrhoea affecting two families sharing one household. Two children (age 10 months and 2 years) suffered severe diarrhoea over 30 and 10 days, respectively. Their uncle had moderate diarrhoea for 2 weeks. In contrast to the other isolates, the uncle's strain (EH109) did not harbour a chromosomal eae gene encoding gamma-intimin nor the plasmid gene E-hly; it also showed a PFGE pattern that was different from the unique pattern of the other isolates. Employing PFGE, phage typing, and P-gene typing, five of the six stx negative isolates were indistinguishable from the stx 2 positive "Bavarian outbreak strain". The only human serum tested, obtained from one asymptomatic contact, contained antibodies to the O157 lipopolysaccharide antigen. Our finding of five stx negative sorbitol-fermenting E. coli O157:H- isolates (harbouring eae and E-hly) associated with an outbreak of non-bloody diarrhoea supports the hypothesis that Stx production is not obligatory for the pathogenicity of E. coli O157 for humans.
Allerberger
F
F
Bundesstaatliche bakteriologisch-serologische Untersuchungsanstalt und Institut für Hygiene und Sozialmedizin, Innsbruck, Austria. franz.allerberger@uibk.ac.at
Dierich
M P
MP
Gruber-Moesenbacher
U
U
Liesegang
A
A
Prager
R
R
Hartmann
G
G
Rabsch
W
W
Tschäpe
H
H
Karch
H
H
D000328:Adult; D001317:Austria / Q000453:epidemiology; D001434:Bacteriophage Typing; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology* / Q000503:physiopathology; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007223:Infant; D008875:Middle Aged; D012720:Severity of Illness Index; D022621:Shiga Toxin / Q000378:metabolism*; D013012:Sorbitol / Q000378:metabolism*
D013012:Sorbitol; D022621:Shiga Toxin