Short-term administration of rifampin was evaluated as a means of preventing or eradicating infection due to foreign bodies. Tissue cages were implanted into guinea pigs and subsequently infected with 103 colony-forming units of Staphylococcus aureus Wood 46. Infection developed in all tissue cages. Rifampin was administered thereafter intraperitoneally at a dosage of 7.5 mg/kg every 12 hr for 48 hr, and the tissue-cage fluid was monitored for possible development of infection by quantitative bacteriologic methods for 15 days. In all cases rifampin prevented or eradicated tissue-cage infection if treatment was initiated either 3 hr before or ⩽12 hr after inoculation of microorganisms but was ineffective if initiated >12 hr after inoculation. In cases of failure of treatment, rifampin-resistant variants could be demonstrated. Rifampin seems to prevent or eradicate tissue-cage infection only if given early after bacterial inoculatio
