Escherichia coli is usually a benign commensal of the gut microflora. However, when E. coli
acquires virulence genes it can multiply rapidly and cause disease through colonisation of
the intestinal mucosa. Escherichia coli can become a significant pathogen in young pigs. We
report an investigation of fatal colisepticaemia in weanling pigs from emerging farms where
piglets and weaners were diarrhoeic and the mortality rate ranged between 15% and 70% in
each litter. Faecal and tissue samples were processed for histopathology, bacteriology and
molecular biology (multiplex and monoplex polymerase chain reaction) and we recovered
enteroaggregative multidrug-resistant E. coli producing EAST-1 enterotoxin. An association
between poor housing conditions and the observed cases was established and future
management programmes were recommended to reduce the impact of such pathogens.
Enteroaggregative E. coli is becoming a major problem in the pig industry. It therefore
becomes necessary to establish the full impact of E. coli on the South African pig industry and
to determine the geographic extent of the problem.