Meropenem-induced alteration of the susceptibility of Escherichia coli and Staphylococcus aureus to the bactericidal activity of human polymorphonuclear leucocytes.

The analysis of the interaction between antimicrobials and phagocytosis in vitro provides information additional to standard MIC and MBC estimations in predicting in-vivo efficacy. This study investigated the effects of meropenem, a newly available carbapenem, on the activities of human neutrophils against Escherichia coli and Staphylococcus aureus. The results were compared with those obtained with imipenem. Pretreatment of E. coli and S. aureus with meropenem and imipenem sensitized the bacteria to leucocytic killing. In the presence of antibiotics, opsonophagocytic killing of E. coli, but not S. aureus, was synergistically enhanced.