Multidrug resistance among Acinetobacter spp. in the USA and activity profile of key agents: results from CAPITAL Surveillance 2010.

Multidrug resistance among Acinetobacter spp. leaves few effective antibiotic options for treatment. To monitor antibiotic resistance in Acinetobacter spp., the US CAPITAL 2010 Surveillance data were evaluated by patient demographics, specimen source, and hospital ward. Isolates (N=514) were collected from 65 sites across the USA and Puerto Rico. Isolates were centrally tested for susceptibility to carbapenems and key antimicrobials by broth microdilution. Colistin was the most effective agent tested, with 95% susceptibility. The overall susceptibility of Acinetobacter spp. was low (39% for piperacillin/tazobactam, 41% for levofloxacin, 45% for ceftazidime, 47-51% for the carbapenems, and 58% for tobramycin). Multidrug resistance (MDR), defined as resistance to ≥3 antimicrobial agent groups, was detected in 54% of the isolates. MDR isolates were most common among elderly patients (65%), lower respiratory tract isolates (62%), and inpatient/intensive care unit isolates (54-58%). These data update trends in the distribution and prevalence of the MDR phenotype in Acinetobacter spp.