Interaction of Intraleukocytic Bacteria and Antibiotics

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Abstract

Bacteria that survive inside polymorphonuclear neutrophils (PMN) following phagocytosis are protected from the bactericidal action of most antibiotics. Two possible explanations are altered metabolism by intraleukocytic bacteria or failure of antibiotics to enter the phagosome. The oxygen consumption of intraleukocytic and extraleukocytic bacteria was measured as an index of bacterial metabolism. PMN respiration and bactericidal activity were suppressed with large doses of hydrocortisone and extraleukocytic bacterial oxygen consumption was abolished by the addition of lysostaphin. Intraleukocytic bacterial continued to consume oxygen suggesting that surviving ingested micro-organisms are metabolically active. Neither penicillin (which cannot kill intraleukocytic bacteria) nor rifampin (which can kill intraleukocytic bacteria) was bactericidal for staphylococci at 5°C. Thus, rifampin is not uniquely able to kill “resting” bacteria.

Authors

Gerald L. Mandell