Treatment of Acinetobacter spp. infections

Acinetobacter spp. are predominantly nosocomial pathogens of growing importance. One of their important features is antimicrobial resistance that includes beta-lactams, aminoglycosides and quinolones. Imipenem, considered the most effective drug against Acinetobacter spp., is not universally active against clinical isolates and therapeutic options are necessary. In vitro studies demonstrate the activity of P-lactamase inhibitors with direct antimicrobial activity, polymyxins, doxycycline and rifampin. Synergy of various combinations has been demonstrated in vitro. Experimental models of infection in mice and rabbits show the efficacy of rifampin and doxycycline. Colistin did not lead to good results in a mouse pneumonia model. There are no randomised, controlled studies on the treatment of Acinetobacter spp. infections. Retrospective comparative studies suggest that ampicillin-sulbactam may be comparable to imipenem in the treatment of pneumonia and bacteraemia. There are a few uncontrolled studies using ampicillin-sulbactam and one study with colistin with results that suggest that they may be acceptable options to treat multi-resistant infections.