ANTIBIOTIC-INDUCED RELEASE OF ENDOTOXIN - IN-VITRO COMPARISON OF MEROPENEM AND OTHER ANTIBIOTICS

The influence of meropenem, a new carbapenem antibiotic, on cell morph ology and in-vitro lipopolysaccharide (LPS) release from Escherichia c oli was compared with that of imipenem, ceftazidime, tobramycin and ci profloxacin. Free and cell-associated LPS was quantified by means of a capture ELISA method based on the recognition of E. coli LPS by monoc lonal antibodies. Microscopically, meropenem was found to induce spher oplast formation similar to that seen with imipenem, while ceftazidime and ciprofloxacin induced filament formation. Free and cell-associate d LPS levels were low in the presence of meropenem, imipenem, ciproflo xacin and tobramycin, but high in the presence of ceftazidime. Reduced endotoxin release appears to be a common property of carbapenem antib iotics. Morphological changes in bacteria in the presence of antibioti cs do not predict their LPS-liberating effect since ciprofloxacin indu ced low levels of LPS despite causing filament formation.