Therapy of staphylococcal infections in monkeys. VI. Comparison of clindamycin, erythromycin, and methicillin.

Intravenous inoculation of a penicillin-resistant, phage type 80/81 staphylococcus caused lethal infection in six of eight untreated monkeys. Daily intragastric administration of clindamycin hydrochloride and erythromycin stearate and intramuscular inoculation of clindamycin-2-phosphate and methicillin, all at a dose level of 50 mg/kg, was followed by mortalities of one of eight, one of eight, none of eight, and one of eight monkeys, respectively. Duration of obvious acute illness in surviving monkeys and time required for complete recovery were not significantly different in the four therapy groups with the exception that duration of acute illness in monkeys treated with clindamycin-2-phosphate (mean, 4.1 days) was significantly shorter than in monkeys given erythromycin stearate (mean, 7.1 days). In vitro sensitivity data and serum antibacterial levels would suggest that methicillin would be the least effective therapeutically, followed by erythromycin stearate and the two clindamycin preparations in that order. However, this prediction was not fulfilled in these studies in experimentally infected monkeys.