Distribution of Enterotoxigenic Staphylococci in Healthy Food Handlers and Biological Properties of Isolates

Abstract

Four hundred food handlers in a box lunch maker in Kanagawa Prefecture were examined for carrier state of enterotoxigenic staphylococci in each season of 1970.
1) Enterotoxigenic strains of Staphylococcus aureus were detected from 88 (22.0%) of 400 persons examined. The incidence was higher in summer and autumn than in spring and winter. It was 7.8% from the nasal cavity, 6.3% from the pharynx, 6.0% from the hair, 7.3% from the fingers, and 6.5% from feces. There was no significant difference in carrier rate between sexes, or any two ages or occupations.
2) A total of 249 S. aureus strains were isolated from 249 samples collected from 154 persons. Of them, 135 were proved to produce enterotoxins. Of the 135 enterotoxigenic strains, 16 produced enterotoxin type A, 9 type B, 35 type C, 57 type D, 3 types A and B, 2 types A and C, 8 types B and D, and 5 types A, C, and D. No strains produced enterotoxin type E. Strains producing type C and those producing type D were detected from all the regions examined.
3) Some persons were found to carry staphylococci producing enterotoxin of the same type in the same region of the body for two or three seasons. Others carried enterotoxigenic strains in the nose or throat in spring. In them, these strains showed a tendency to spread to other regions and become resident there in summer and autumn.
4) Almost all the 135 enterotoxigenic strains produced hemolysin, a yellow pigment, lipase, and egg-yolk factor. Many of these strains were fibrinolysin-positive and lysed by N.C.T.C. phages. Some of them were resistant to antibiotics. These results indicate that enterotoxigenic staphylococci carried by healthy food handlers are important causative agents of staphylococcal food poisoning.