Reduced degradability by lysozyme of staphylococcal cell walls after chloramphenicol treatment

The effectiveness of host defence against staphylococcal infections depends on the capability of phagocytes to degrade the bacterial cell walls. Treatment with bacteriostatic agents like chloramphenicol could cause problems since under these drugs staphylococcal walls will be substantially thickened. This study presents evidence that the additional wall material built in the presence of chloramphenicol could moreover be rendered more resistant to lysosomal enzymes: In vitro at pH 5.6, lysozyme from hen egg-white proved to degrade the chloramphenicol-wall material at a velocity reduced to 20% of that of the normal wall. Thus, during the degradation of chloramphenicol-treated staphylococcal cell walls the phagocytes have to deal not only with a quantitative but also with a qualitative problem. Possible reasons for the reduced degradability as to chloramphenicol-induced alterations of the wall composition as well as to activating effects of lysozyme on cell wall autolysins are discussed in view of microbiological and medical implications.