Interactions between Antibiotics and Human Neutrophils in the Killing of Staphylococci: STUDIES WITH NORMAL AND CYTOCHALASIN B-TREATED CELLS

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Abstract

Normal and antibiotic-pretreated staphylococci were incubated with human neutrophils to determine the interactions between cells and antimicrobials in the killing of the organisms. Staphylococcus aureus 502A pretreated during log-phase growth with subinhibitory (¼ minimum inhibiting concentration) (MIC) concentrations of penicillin G were more susceptible to killing by normal neutrophils than untreated bacteria (intracellular survival 0.17±0.04 vs. 1.5±0.38%, mean±SEM, respectively, at 35 min in 14 experiments; P < 0.01 by t test). Furthermore, this enhanced susceptibility to killing was observed even when phagosome formation was inhibited by cytochalasin B (65.6±4.6% pencillintreated vs. 30.5±4.5% untreated killed at 30 min in 14 experiments, P < 0.001). Pretreatment of S. aureus with vancomycin similarly enhanced susceptibility to killing by cytochalasin B-treated polymorphonuclear leukocytes (PMN), whereas pretreatment with gentamicin did not.

Authors

Richard K. Root, Raul Isturiz, Abdolghader Molavi, Julia A. Metcalf, Harry L. Malech