Agglutination of encapsulated bacteria

Abstract

During the past year a systematic study of the group of encapsulated bacteria (including Bacterium pneumoniæ Friedländer, Bacterium rhinoscleromatis v. Frisch, Bacterium ozenæ Abel-Löwenberg, and Bacterium capsulatus mucosus Fasching) has been carried on, employing for the purpose biometrical methods somewhat similar in character to those suggested by Winslow 1 in his work on the Coccaceæ.

During the course of the investigation, immunological methods have been used. At the outset, the reaction of agglutination was tried. Paltauf was the first (quoted by Beham 2 ) to suggest that the agglutination of encapsulated micro-organisms is inhibited because the bacilli are surrounded by a slimy nucleo-protein capsule. Porges 3 was able to supply experimental proof of this. v. Eisler and Porges 4 then elaborated a method of removing the capsule, after the application of which these bacteria were agglutinable.

My own work done independently of Beham has given results in harmony with his. I have found that Bacterium rhinoscleromatis on injection into rabbits yields a potent agglutinating serum.

Using this serum, agglutination not only of the homologous microorganism has been obtained but a positive result was found to occur also when four other strains of the same species, from widely different sources, were tested. The bacteria agglutinated in a dilution of the serum, ranging from 1-400 to 1-800. Two strains of Bacterium ozane, one strain of Bacterium capsulatus mucosus Fasching, and one strain of Bacterium pneumonia Friedlander, were not agglutinated at all by the same serum. The strains of Bacterium rhinoscleromatis which agglutinated were no longer encapsulated. All the other species still showed a capsule. One of the strains of rhinoscleromatis when originally isolated was not agglutinated by the serum of the patient from whom it was isolated and at that time it was encapsulated (Thro, Proceedings New York Pathological Society, April and May, 1910).