The serological classification of Staphylococcus

Abstract

The classification of staphylococcus has been made according to pigment-producing abilities or properties on cultivation. Several investigations on serological classification have also been reported. However, the establishment of serological classification has been made difficult because of spontaneous agglutination in certain strains of staphylococcus which takes place in the presence of physiological saline solution.
It was found by the authors that the treatment of the bacilli with 2% NaOH completely inhibited the spontaneous agglutination and thus a homogeneous bacillary suspension was easily obtained. By using immune serum obtained by immunizing rabbits with this suspension as antigen the following results were obtained.
1) From six antigenically different strains (SCA-2, SCA-6, SCA-12, SCA-13 and SCA-24 were isolated from foods which presumably, caused poisoning and SCA-32 isolated from purulent lesion) which were selected as standard strains, were prepared five factor sera which specifically agglutinate these standard strains, and one serum which contains a common antibody.
2) Three hundreds and forty six strains of staphylococci isolated from various materials were classified into five types and sixteen sub-types. Several strains could not, however, be classified.
3) Staphylococci belonging to type 1 and type 2 are considered to be pathogenic.
4) Only staphylococci of type 1 and type 2 are sensitive to phages. Serological classification is, therefore, desirable as a screening test before determination of phage types.
5) This form of classification is considered to have a practical value.