Enterotoxigenic enteric bacteria in foods and outbreaks of food-borne diseases in Sweden

Abstract
SUMMARY: All of 86 foods routinely examined for potentially pathogenic enteric bacteria were found to harbour one or more coliform species. None of the strains isolated produced heat-labile enterotoxin (LT) or showed invasive properties. The suckling mouse test indicated that one strain ofEscherichia coliproduced heat-stable enterotoxin (ST). Twelve incidents of suspected food poisoning were also investigated. In two of them the foods examined contained LT-producing strains ofE. coliand in two there were LT-producing strains ofKlebsiella pneumoniae. The counts of viable enterotoxigenic micro-organisms in these foods were 3000–30 000E. coli/g and 50 000 to 1 millionK. pneumoniae/g. The dominant symptom in all the incidents was watery diarrhoea. These seem to be the first reported cases of foodborne enterotoxigenic enteric bacteria in Europe. Though enterotoxigenicE. coliand related gram-negative enterotoxin-producing species are rare in correctly handled food in Sweden, these micro-organisms should be searched for when outbreaks of food poisoning are investigated.