A Stewardship Approach to Combating Multidrug-Resistant Acinetobacter baumannii Infections With Minocycline

Background Antimicrobial Stewardship Programs should consider old antimicrobials for emerging multidrug-resistant (MDR) organisms such as Acinetobacter baumannii. Our purpose is to evaluate susceptibilities of minocycline to MDR-A. baumannii and assess the outcomes of patients treated with minocycline. Methods Consecutive isolates from 67 patients with MDR-A. baumannii were tested to determine susceptibilities to tetracycline, minocycline, tigecycline, ampicillin/sulbactam, imipenem/cilastatin, and colistin. Patients receiving minocycline from September 1, 2010, to March 31, 2011 were analyzed for demographics, penicillin allergy, clinical and microbiologic response, length of stay (LOS), infection-related LOS, and mortality. Results Minocycline was susceptible to 32 (48%) of 67 A. baumannii isolates. Of the imipenem/cilastatin- and ampicillin/sulbactam-resistant isolates, minocycline was susceptible to 18 (38%) of 47. Five patients received minocycline in combination with ampicillin/sulbactam or colistin for pneumonia (n = 3), bacteremia (n = 1), and skin and soft tissue infection (n = 1). The median treatment duration, LOS, and the infection-related LOS were 10, 34, and 21 days, respectively. All patients had microbiologic cure, and 4 had clinical response. Conclusions Minocycline showed clinical utility for MDR-A. baumannii infections. Antimicrobial Stewardship Programs should consider minocycline for MDR-A. baumannii infections and monitor patient outcomes.