Studies on Staphylococcal Food Poisoning (I)

Abstract

Isolates of Staphylococcus aureus from 34 food poisoning incidents in Tokyo during 1969-1970 were examined for their ability to produce enterotoxins A, B, C and D. Enterotoxins were produced in NZ-Amine medium with shaking and the culture supernatants were concentrated to 1/25-1/30 volume by dialysis against equal volume of solution of 50% polyethylene glycol 20, 000. Each enterotoxin in the concentrated culture supernatants was detected serologically by slide gel diffusion test.Enterotoxins A, B, C and D were demonstrated on isolates from 33 out of 34 incidents (97%), and in some instances two enterotoxins were produced by one strain; isolates from 8 incidents produced enterotoxin A, 1 produced enterotoxin B, 7 produced enterotoxin C, 3 produced enterotoxin D and 14 produced enterotoxins A and D. In a result of the survey, enterotoxin A, and enterotoxins A and D were predominant types in the food poisoning.All of 34 strains of Staphylococcus aureus from food poisoning incidents could be typed by means of coagulase typing, viz., 10 as type II, 9 as type III, 7 as type VI and 8 as type VII, respectively.In addition, a total of 400 strains of Staphylococcus aureus isolated from fingers, noses and feces of healthy subjects, and commercial foods without the association to food poisoning incident, which consisted of each 100 strains per a source, were examined for enterotoxin production and coagulase typing.Three hundred and sixty-two strains out of them produced enterotoxins A, B, C or D, and some strains had productivity of two, three or four enterotoxins. Out of enterotoxin producing strains, 99 produced enterotoxin D, 90 produced enterotoxins C and D, 48 produced enterotoxins A and C, 39 produced enterotoxins A, C and D, 30 produced enterotoxin C and 16 produced enterotoxin A (see table 2).Four hundred strains of Staphylococcus aureus from the materials not associated with food poisoning incident were also typed by coagulase typing, viz., 10 as type I, 35 as type respectively. From the results mentioned above, it was indicated that there was no correlation between enterotoxin types and coagulase in the strains used, while the most number of the strains producing enterotoxin B were typed as coagulase type IV or V.