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

Abstract

SUMMARYAll 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.