zoonoses and communicable diseases common to ... - PAHO/WHO

254 BACTERIOSESunsuccessful in isolating Staphylococcus, but the presence of enterotoxin A wasconfirmed (Bone et al., 1989). In various Mediterranean countries, Staphylococcusis one of the most important agents in ovine mastitis. Not only can ovine staphylococcuscause economic losses, it could also be a public health problem. Food poisoningis probably the most important foodborne disease in Spain and other countriesof the region. The vehicle of poisoning could be cheese made from sheep’smilk. In Spain, 46 of 59 isolates of S. aureus produced enterotoxin C; 2, enterotoxinA; 1, enterotoxin D; and 2, enterotoxins A and C (Gutiérrez et al., 1982). In developingcountries, where the refrigeration of milk after milking leaves much to bedesired, it is possible that milk and milk products are an important source of staphylococcalintoxication.According to recent studies, a high proportion of strains isolated from staphylococcalmastitis produce enterotoxin A, which causes many human outbreaks.Several studies were successful in isolating the S. aureus phage type 80/81 fromskin lesions and cow’s milk, which is related to epidemic infections in man. One ofthe studies proved that phage type 80/81 produced interstitial mastitis in cows. Thesame phage type was found among animal caretakers, which indicates that thebacterium can be transmitted between man and animals and that the latter mayreinfect man.Infected fowl and dogs (see the section on occurrence in animals) may also giverise to and be a source of staphylococcal poisoning in man.One subject that deserves special attention is the appearance of antibiotic-resistantstrains in animals whose food contains antibiotics. There is concern regardingthe possible transmission of these strains to man. On several occasions, resistantstrains have been found both in animals (cows, swine, and fowl) and in their caretakers,with the same antibiotic resistance. Moreover, “human” strains (phage typed)have occasionally been isolated from the nostrils and lesions of other species ofdomestic animals.A variety of foods and dishes may be vehicles of the toxin. If environmental conditionsare favorable, S. aureus multiplies in the food and produces enterotoxins.Once made, the toxin is not destroyed even if the food is subjected to boiling for theusual cooking time. Consequently, the toxin may be found in food while staphylococciare not.Poisoning is usually caused by primarily protein-based cooked foods that are contaminatedduring handling and left at room temperature. Red meat and fowl wereresponsible for 47.3% of the outbreaks in the US (ham was the most common sourcein that country) and 77.2% in England. In Spain, primarily mayonnaise and foodscontaining mayonnaise were implicated; in Germany, four outbreaks were due tomeat and three to eggs and milk products (Genigeorgis, 1989). During a Caribbeancruise, 215 of 715 passengers were poisoned by cream-filled pastries served at twodifferent meals on board. The remaining pastries were thrown out and could not bestudied, but enterotoxigenic strains of S. aureus phage type 85/+ were isolated fromthe feces of 5 of 13 patients and from none of the controls. Isolates of the samephage were obtained from a perirectal sample and from a forearm lesion from twoof seven members of the ship’s crew who were in charge of pastry preparation(Waterman et al., 1987).An important causal factor in poisoning is keeping food at room temperature orinadequate refrigeration, practices which allow staphylococci to multiply. Lack of