Patterns of Total Extracellular Protein Secretion by a Number of Clinically Isolated Strains of Staphylococcus aureus

Abbas-Ali & Coleman (1977) studied the characteristics of total extracellular protein secretion by Staphylococcus aureus strain Woad 46. The differential rate of exoprotein secretion was low during the exponential growth phase but increased on entry into the post-exponential phase of the growth cycle. Subsequently, it was demonstrated that an increase in the rate of exponential growth produced a corresponding reduction in the differential rate of exoprotein formation (Coleman & Abbas-Ali, 1977). These characteristics were consistent with the ‘competition ’ model for the regulation of extracellular protein formation described by Coleman, Brown & Stormonth (1975). It is possible that the characteristics of the highly haemolytic Wood 46 strain of S. aureus, which has been widely used in laboratory studies, differed from clinically isolated strains of the organism. This possibility has been examined by taking a random selection of clinical isolates and determining their patterns of total exoprotein production under conditions similar to those used by Abbas-Ali & Coleman (1977). M E T H O D S Organisms. Ten recently isolated strains of Staphylococcus aureus (numbered 1 to 10) were kindly provided