Carbapenem-resistant Acinetobacter baumannii: in pursuit of an effective treatment

Abstract

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) has gained global notoriety as a critically important nosocomial pathogen. It mostly affects debilitated patients, causing pneumonia and bloodstream infections with high mortality rates. Difficulties in treating CRAB infections stem from a formidable resistance profile that leaves available only a few antibiotics of uncertain efficacy such as colistin and tigecycline. Despite the relentless attempts to improve therapeutic approaches (as depicted in colistin-oriented randomized clinical trials and the numerous observational studies), progress is still limited.

Aims: We aim (a) to assist physicians to adapt therapeutic approaches in CRAB infections by considering all potentially available antimicrobials, and (b) to present directions for future investigations that emerge through treatment efforts in endemic settings.

Sources: Articles and reviews from PubMed and Scopus databases; studies from ClinicalTrials.gov; presentations from ECCMID congresses and IDWeek meetings.

Content: The review provides a succinct overview of the important pharmacokinetic/pharmocodynamic parameters of relevant antimicrobial agents, a critical appraisal of randomized control trials and observational studies, suggestions for increasing the strength of observational studies and directions facilitating the choice of therapeutic regimens by severity of infection and status of the host.

Implications: The lack of an optimal therapeutic regimen for CRAB thus far, as shown in this review, suggests the need to thoroughly investigate alternative approaches through carefully designed trials that should include all relevant drugs. Some of these alternative directions are indicated in the present review.

Keywords: Acinetobacter baumannii; HAV/VAP; carbapenem resistance; extensive drug resistance; treatment.