The behavior of UV-induced coagulase-positive and negative mutants of Staphylococcus aureus.

The role of coagulase in staplhylococcal infections is tincertain. It has been clemonstrated(1) that coagulase-negative hemolytic staphylococci wllen treated witlh coagulase and injected intracerebrally into mice exlhibit a higlher degree of virulence than the same organisms without treatment with coagulase. Other workers(2,3) have also found an association of coagtulase with virulence. However , Kapral and co-workers(4-6) lhave induced a mutant, Staphylococcus aurcus strain 18ZD, from the parent S. aureus strain 18Z by uv irradiation. They have found that this mutant, altlhouglh it produces coagulase as its parent does, is unable to multiply in the organs of the reticuloendotlhelial system of mice and rabbits wlhile its parent possesses this ability. This work, as it stands, as well as the study of Alami and Kelly(7), have raised questions regarding the role of coagulase in staplhylococcal infections. The present study indicates that the uv irracliation employed for the production of coagulase-positive and negative mutants of S. azurcus lhas altered the physiology of the above-mentioned mutants and such alterations induced by mutagens should be considered in assessing the role of coagulase in staphylococcal infections.