Vero cytotoxigenic Escherichia coli infection in dairy farm families

Fecal samples from 335 dairy farm residents and 1458 cattle on 80 farms were tested for Vero cytotoxin (VT)-producing Escherichia coli (VTEC). Residents were also tested for antibodies to VT1 and O157 lipopolysaccharide (LPS), Residents and cattle on farms with VTEC-positive persons or E, coli O157:H7-positive cattle were retested, Twenty-one persons (6.3%) on 16 farms (20.8%) and 46% of cattle on 100% of the farms had VTEC in fecal samples, Human VTEC isolates included E, coli O157:H7 and 8 other serotypes, 4 of which were present in cattle on the same farms, More persons had antibodies to VT1 (41%) than to O157 LPS (12.5%), Seropositivity to O157 LPS was associated with isolation of E, coli O157:H7 on the farm (P = .022), Human VTEC infection was negatively associated with age (P < .05) and was not associated with clinical illness, Many dairy farm residents experience subclinical immunizing VTEC infections at a young age, which frequently involve non-O157 VTEC found in cattle.