SYNTHESIS OF MICROCAPSULE BY STAPHYLOCOCCUS-AUREUS IS NOT RESPONSIVE TO ENVIRONMENTAL PHOSPHATE CONCENTRATIONS

The polysaccharide microcapsule of Staphylococcus aureus has been repo rted to be differentially expressed depending on growth conditions, wi th phosphate concentration being the critical environmental component. This study evaluated the effect of growth of a serotype 8 strain of S . aureus in phosphate-replete and phosphate-limiting media on microcap sule production. The presence of the cell wall polymers microcapsule a nd teichoic acid was measured by both gas chromatography-mass spectrom etry and liquid chromatography-mass spectrometry. Production of microc apsule was unaffected by changes in the environmental phosphate concen tration. There was, additionally, no evidence for a shift from teichoi c acid to teichuronic acid synthesis.