Abstract
Mishulow, Mowry and Scott 1 demonstrated that exotoxic filtrates could be obtained from whooping cough cultures. They planted their organisms on chocolate agar over which they had poured a small amount of horse serum-beef heart broth. The small amount of diluent made the harvest of toxin necessarily small. On the other hand, Craster and Smith 2 mentioned that there was a signal absence of toxin formation in planted cultures, and Riesenfeld 3 stated that there was no proof that this bacillus produced a toxin in ascitic broth. Besredka 4 isolated toxic substances termed endotoxins from the dried and powdered organisms.
In 1928, we found that pertussis bacillus produced a substance in culture growth, the exact nature of which was problematic. With the report of Mishulow, Mowry and Scott, we felt that further work should be done along this line. Since large amounts of toxin could not be practically produced on solid preparations, various liquid media were tried. We found that Pelouze's and Viteri's gonococcous medium slightly modified by omission of the agar could be used to advantage. The formula was as follows : 250 cc. of veal infusion, 80 cc. of brain infusion, 3.3 gm. of peptone, 1.6 gm. of NaCl, and 1.6 gm. of sodium phosphate. The medium had a pH of 7.2.
There are numerous protein factors in this medium, and when we tested out the unplanted control filtrates by intradermal injection of amounts of 0.1 cc., we found that humans gave positive reactions in a little less than 1% of the individuals tested and that in all instances veal was the reacting factor.
Of the 4 strains of the American Type Culture Collection experimented with, No. 778, a strain isolated by W. H. Park, gave us best results and was used in our subsequent work.
The bacillus was planted and grown arbitrarily for 10 to 14 days in the medium described. There was a rapid growth on the bottom of the flask after the fourth to the fifth day.
Conclusion. Whooping cough bacillus when grown in the liquid medium as described, produced a substance which in the dosages used caused a local skin reaction in either 6 or 24 hours after injection in all the 680 individuals tested. Whether there is a specific fraction for whooping cough in this material has not been determined.
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