In vivo efficacy of azlocillin and amikacin versus ciprofloxacin with and without amikacin in experimental right-sided endocarditis due to Pseudomonas aeruginosa.

The efficacy of azlocillin + amikacin was compared to ciprofloxacin (with and without amikacin) in 96 rabbits with right-sided endocarditis due to Pseudomonas aeruginosa. Animals received either: no therapy (controls); amikacin (15 mg/kg/day) + azlocillin (400 mg/kg/day); ciprofloxacin (80 mg/kg/day) or amikacin + ciprofloxacin (above dosages). All three antibiotic regimens were significantly more effective than no therapy in reducing mortality (p less than 0.0005), preventing pulmonary infarction (p less than 0.0005) and reducing mean vegetation titers of P. aeruginosa (p less than 0.0005). Also, the three therapy regimens were equivalent in preventing bacteriologic relapse after discontinuing therapy. No development of antibiotic resistance in vivo was observed.