Relationship between morphological changes and endotoxin release induced by carbapenems in Pseudomonas aeruginosa

The relationship between morphological changes and endotoxin release induce d in vitro by carbapenems in a clinical isolate of Pseudomonas aeruginosa w as examined. The time-course and magnitude of endotoxin release induced var ied among imipenem, panipenem, meropenem and biapenem and related to the mo rphological changes caused by these agents which variously affected cell sh ape, cell-wall disintegration and cell lysis, The amount of endotoxin relea sed by carbapenem-treated cells correlated with both the cell-wall morpholo gy and bacterial shape immediately before lysis, Meropenem and biapenem cau sed markedly increased endotoxin release during cell lysis and cell-wall di sintegration, whereas imipenem and panipenem caused much less release of en dotoxin.