Acinetobacter baumannii Resistance Trends in Children in the United States, 1999–2012

Background. Acinetobacter baumannii is a common cause of healthcare-associated infections. Carbapenem-resistant (CR) A baumannii is a significant threat globally. We used a large reference laboratory database to study the epidemiology of A baumannii in children in the United States. Methods. Antimicrobial susceptibility data from The Surveillance Network were used to phenotypically identify antibiotic resistance in A baumannii isolates in children 1–17 years of age between January 1999 and July 2012. Logistic regression analysis was used to calculate trends in the prevalence of antibiotic resistance in A baumannii. Isolates from infants (<1 year old) were excluded. Results. The crude proportion of cephalosporin-resistant (CephR) A baumannii increased from 13.2% in 1999 to 23.4% in 2012 with a peak of 32.5% in 2008, and the proportion of CR A baumannii increased from 0.6% in 1999 to 6.1% in 2012 with a peak of 12.7% in 2008. From 1999 to 2012, the proportion of CephR and CR A baumannii increased each year by 3% and 8%, respectively (CephR odds ratio [OR] = 1.03, 95% confidence interval [CI], 1.01–1.04; CR OR = 1.08, 95% CI, 1.05–1.12); however, after 2008, a significant decrease in trend was observed (CephR OR = 0.78, 95% CI, 0.71–0.87; CR OR = 0.73, 95% CI, 0.62–0.86), but resistance remained higher than baseline (1999). Conclusions. Overall, between 1999 and 2012, CephR and CR A baumannii isolates increased in children; however, a decreasing trend was observed after 2008.There is a need for ongoing surveillance of A baumannii infections and continued assessment of effective prevention strategies in vulnerable populations.