Results of Feeding Staphylococcus Filtrates to Monkeys

Abstract

Attempts to produce in the lower animals symptoms resembling those in human volunteers fed with staphylococcus filtrates have not generally been successful. Barber stated that kittens, puppies and monkeys show no symptoms after ingesting large quantities of milk cultures of the toxic staphylococcus isolated by him: “or at all events, the symptoms are very slight.” Unpublished work by Dack and others in the Bacteriology Laboratory of the University of Chicago has similarly given negative results. Rhesus monkeys of approximately 6 kilos have repeatedly been fed large amounts—up to 60-70 cc.—of staphylococcus filtrates of proved toxic power for man without in any instance producing the “food poisoning” symptoms observed in human volunteers. These consistently negative results led us to abandon for a time attempts to produce illness in monkeys by feeding toxic filtrates. In March, 1931, opportunity was offered us through the courtesy of Dr. H. C. Clark, Director of Gorgas Memorial Laboratory, Panama, of repeating these experiments with a number of smaller monkeys of different species. The monkeys used were chiefly the red spider (Ateles geoffroyi), black spider (Ateles ater), black howler (Alouota palliata inconsonans), and white face (Cebus capucinus capucinus). They were nearly all juvenile, weighing between one and 2 kilos. The filtrates fed were from staphylococcus broth cultures after 2 to 3 days' growth; their gastro-intestinal toxicity for man was in each instance established by their effect in 2 cc-10 cc. amounts on human volunteers. Thirteen monkeys were fed amounts ranging from 5 cc.-20 cc. A rubber catheter was introduced into the stomach, and measured amounts of the filtrate were slowly injected by a graduated syringe. In five (2 red spiders, 2 black howlers, 1 black spider) definite symptoms were observed of a similar character to those described in human subjects.