The Relationship of the Aluminium Phosphate Precipitation of Organisms of Haemophilus pertussis strains to their other Biological Properties

SUMMARY: Of 46 strains of Haemophilus pertussis, 34 recently isolated strains were all agglutinated by Phase 1 antiserum. Of 12 laboratory strains, 5 had lost their agglutinability. The agglutinable strains were precipitated by aluminium phosphate, and lysed by sodium hydroxide or 10% sodium desoxycholate and were virulent to mice. The virulent strains, which were precipitable by aluminium phosphate, produced toxic substances in a fluid culture. Precipitation by aluminium phosphate provides a quick method for distinguishing virulent and avirulent strains of H. pertussis.