OBJECTIVETo evaluate the efficacy and drug resistance of azithromycin administered via continuous infusion versus intermittent administration in rats with Mycoplasma pneumonia-induced pneumonia.

METHODSPneumonia was induced in rats by intranasal administration of mycoplasma suspension. The rats with established pneumonia were randomly divided into continuous and intermittent infusion groups with intraperitoneal azithromycin injection on a daily basis for 6 consecutive days, or for 3 consecutive days followed by a 3-day rest (which was repeated twice), respectively. The bronchoalveolar lavage (BAL) and venous blood were collected before and at 3, 6, 9, and 12 days during or after the treatments for MIC test. The rats were killed for lung pathological examination, and the plasma samples were obtained for drug assays by HPLC.

RESULTSPathological examination of the lungs demonstrated better improvement in the intermittent group than in continuous group. At 12 days of the treatment, the MIC value was higher in the continuous group than in the intermittent group.

CONCLUSIONIntermittent azithromycin administration produces better therapeutic effect against Mycoplasma pneumonia than continuous drug delivery in rats with less likeliness of inducing drug resistance.