โMethods
Avian and human E. coli isolates
Fresh faecal samples were collected randomly from five
poultry farms (approximately 4 km apart) in the parish of
St. Catherine, Jamaica between 2000 and 2001. Samples
(100 g) were collected over a 42-day period at 3-day intervals,
kept at 6°C and bacteriological analyses were performed
within 4 h of collection. The flocks investigated, as
well as other flocks on the farms consisting of older birds,
were not treated with antibiotics during the period of
investigation. Farm records indicated that no antimicrobial
agents were administered during the 12 months prior
to sample collection. Feed and water samples were sampled
at each visit to the different farms and screened for E.
coli resistant to tetracycline. Domestic animals were either
absent or located at least 500 m from the broiler operations