The Pathogenic Role of Coagulase-Negative Staphylococci

Summary.— Coagulase‐negative staphylococci are now recognized as colonizers of internal artificial prostheses and as primary pathogens of the urinary tract, in addition to their more traditional role in causing bacteraemia associated with cardiac lesions. Bacteriological investigations into the colonization of ventriculo‐atrial shunts are described; they revealed that nearly all the cocci responsible for this complication belonged to one subgroup, S. II, within the general staphylococci and micrococci. Tests for lysozyme and de‐oxyribonuclease activity were made on staphylococci and micrococci recovered from the urinary tract and from colonized prostheses to see whether production of these enzymes gave better indications of pathogenicity than the well‐established coagulase test. Many strains from the urinary tract produced both lysozyme and de‐oxyribonuclease, while almost all strains from prostheses produced neither.