A case-control study of sporadic infection with O157 and non-O157 verocytotoxin-producing Escherichia coli.
Potential risk factors for sporadic verocytotoxin-producing Escherichia coli (VTEC) infection in Belgium were investigated in a matched case-control study. Thirty-seven cases, 8 infected with O157 VTEC strains (all eaeA-positive), 29 with non-O157 VTEC strains (13 eaeA-positive and 16 eaeA-negative) and 69 matched controls were interviewed. In a conditional logistic regression analysis, consumption of fish appeared to be a risk factor for infection (adjusted odds ratio (OR) 3.25, P = 0.04). Contact with dogs (OR 0.27, P = 0.04) and consumption of shellfish (OR 0.19, P = 0.05) showed a negative association, corresponding to a decrease in risk. These findings might be explained if low level environmental exposure to VTEC induces protective immunity. Eating raw meat, a frequent habit in Belgium, or hamburgers, or eating in a fast-food restaurant was not more frequently reported by cases than controls. The exposures causing sporadic infections with VTEC, in particular non-O157 strains, may be very different from those which led to outbreaks, and may account for more cases overall.
Piérard
D
D
Department of Microbiology, Academisch Ziekenhuis Vrije Universiteit Brussel, Belgium.
Crowcroft
N
N
De Bock
S
S
Potters
D
D
Crabbe
G
G
Van Loock
F
F
Lauwers
S
S
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis*; D001530:Belgium / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003603:Cytotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000302:isolation & purification* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D019453:Escherichia coli O157 / Q000302:isolation & purification* / Q000472:pathogenicity; D005247:Feeding Behavior; D005260:Female; D005399:Fishes; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012044:Regression Analysis; D012307:Risk Factors; D022622:Shiga Toxin 1
D001427:Bacterial Toxins; D003603:Cytotoxins; D022622:Shiga Toxin 1