The clinical evaluation of staphylococcal anti-alpha haemolysin titres in patients' sera.

a haemolysin and the pathogenicity of Staphylococcus aureus has long been a matter for discussion. Christie, North, and Parkin (1946) stated that the production of a haemolysin is essential for full pathogenicity, and that coagulase-positive strains which produced no a haemolysin might be regarded as non-pathogenic. Marks (1952) found a close correlation between pathogenicity and the production of a haemolysin. On the other hand, Elek and Levy (1950) and Lack and Wailling (1954) found that a haemolysin was not an absolute criterion of pathogenicity. It was suggested by Lack and Wailling that the discrepancy of results might partly be explained by a difference in sources, and on occasions by an over-growth of non-toxigenic strains in necrotic foci. Rogers (1956) has performed experiments which suggest that certain macro-anions, such as chondroitin sulphate, hyaluronic acid, heparin, and the nucleic acids, may, in vivo, inhibit the formation of toxins by the organism. The five cases reviewed in this paper were all of infections by a virulent strain of Staphylococcus aureus, phage type 80. An attempt will be made to show that in such cases the staphylococcal anti-a haemolysin titre of the patient's serum is a valuable guide to progress and an aid to the detection of latent infection by Staphylococcus aureus.