A Cultural Method for Classifying Staphylococci as of the “Food Poisoning” Type

Abstract

Staphylococci isolated from sporadic cases of food poisoning are a problem in any health department since so much is dependent upon feeding tests for experimental proof of their etiological significance. Often such evidence is lacking or difficult to obtain. Los Angeles County has experienced difficulty with this problem many times. Conditions, therefore, favored the gathering of a representative collection of strains of staphylococci. Investigation of these strains has led to the development of a valuable cultural test which separates enterotoxic strains from the non-enterotoxic within the collection. So far as we know, this is the first time that a cultural characteristic common to the enterotoxic strains has been demonstrated.

Owen 1 isolated staphylococci from dried beef which had affected 19 persons. Twenty-eight years later, the American Medical Association 2 published an editorial on staphylococcus food poisoning that dealt with the successful feeding tests made in human beings by Dack, Cary, Woolpert, Oram and Wiggers. 3 This test was a revival of the one used by Barber, 4 who suffered gastro-enteritis after drinking a culture of staphylococcus. Jordan and his coworkers 5 confirmed the results of feeding tests made in human beings and with McBroom 6 introduced feeding tests conducted in monkeys. Woolpert and Dack 7 described tests in monkeys that seemed to be more successful than those conducted by Meyer 8 and ourselves. Other work, including that of Dolman 9 warrants the conclusion that the reaction of human beings is the most dependable physiological test of food poisoning. Meyer 8 mentions the fact that alarming symptoms have developed in human volunteers. Therefore, for various reasons routine human tests are impractical.