Determination by a Microslide Method of the Amounts of Staphylococcal Enterotoxins A, B and C Produced by Strains Associated and Not Associated with Food Poisoning

Abstract

The aim of the present work was to estimate quantitatively by a microslide method the amounts of enterotoxins (ET) A, B and C produced by strains of Staph. aureus associated (13 strains) and not associated (200 strains) with food poisoning.The geometric means of estimated amounts of ET-A, ET-B and ET-C produced in brain-heart infusion broth by strains associated with food poisoning were 1.67±0.08, 1.13±0.14 and 1.75±0.07μg per milliliter and those of strains not associated with food poisoning were 0.76±0.10, 1.56±0.09 and 0.98±0.09μg per milliliter, respectively. The differences in amounts of ET-A, ET-C and ET (A+B+C) between strains associated with food poisoning and strains not associated with food poisoning, were statistically significant.It was observed that the amount of ET (A+B+C) produced by strains associated with food poisoning was more than 3.0μg/ml. On the other hand, 80 of 200 strains not associated with food poisoning produced more than 3.0μg ET (A+B+C)/ml. The distribution of coagulase types observed in the 80 strains was the same pattern as that of the 200 strains. However, the coagulase types of strains (31 out of 80 strains) which produced ET-A were II, III, VI and VII. These results are consistent with reports indicating that only strains having coagulase types II, III, VI and VII were associated with food poisoning, and furthermore that the type of ET identified in cases of food poisoning in Japan and England was almost exclusively ET-A type.