Carbapenem-resistant (CRE) are increasingly identified in children in the United States, but data on the epidemiology of CRE in this population are limited. The objectives of this study were to characterize the risk factors for colonization or infection with CRE and describe the microbiologic characteristics of pediatric CRE isolates. We performed a multicenter matched case-control study from January 2011 to October 2015 at three tertiary care pediatric centers. Case patients were hospitalized children with CRE isolated from clinical cultures and were matched in a 2:1 ratio to control patients with carbapenem-susceptible (CSE). Risk factors for colonization or infection with CRE were then evaluated using a multivariable conditional logistic regression. Additionally, we comprehensively reported the antimicrobial susceptibility pattern for CRE isolates. Sixty-three case patients were identified and matched to 126 control patients. On multivariable analysis, antipseudomonal antibiotic exposure within the previous 3 months (odds ratio [OR], 5.20; 95% confidence interval [CI], 1.71 to 15.9; = 0.004), prior surgery (OR, 6.30; 95% CI, 1.83 to 21.6; = 0.003), and mechanical ventilation (OR, 12.4; 95% CI, 1.26 to 122; = 0.031) were identified as risk factors for colonization or infection with CRE. Pediatric CRE isolates demonstrated relatively low rates of resistance to amikacin (5%) and ciprofloxacin (25%). Our findings support an important role for antibiotic stewardship interventions limiting the unnecessary use of antipseudomonal antibiotics as a strategy to prevent widespread emergence of CRE in children. Future studies should further characterize molecular determinants of antibiotic resistance among pediatric CRE isolates.

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Accurate detection of carbapenemase-producing glucose-nonfermenting Gram-negative bacilli (CPNFs), including Pseudomonas aeruginosa and Acinetobacter baumannii, is necessary to prevent their dissemination within health care settings. We performed a method comparison study of 11 phenotypic carbapenemase detection assays to evaluate their accuracy for the detection of CPNFs. A total of 96 carbapenem-resistant glucose-nonfermenting isolates were included, of which 29% produced carbapenemases. All CPNFs were molecularly characterized to identify ␤-lactamase genes. A total of 86% of the carbapenemase-producing P. aeruginosa isolates produced class B carbapenemases. Several assays performed with a sensitivity of Ͼ90% for the detection of carbapenemase-producing P. aeruginosa, including all rapid chromogenic assays and the modified carbapenem inactivation method. Most included assays, with the exception of the Manual Blue Carba assay, the Modified Carba NP assay, the boronic acid synergy test, and the metallo-␤-lactamase Etest, had specificities of Ͼ90% for detecting carbapenemase-producing P. aeruginosa. Class D carbapenemases were the most prevalent carbapenemases among the carbapenemase-producing A. baumannii strains, with 60% of the carbapenemaseproducing A. baumannii isolates producing acquired OXA-type carbapenemases. Although several assays achieved Ͼ90% specificity in identifying carbapenemaseproducing A. baumannii, no assays achieved a sensitivity of greater than 90%. Our findings suggest that the available phenotypic tests generally appear to have excellent sensitivity and specificity for detecting carbapenemase-producing P. aeruginosa isolates. However, further modifications to existing assays or novel assays may be necessary to accurately detect carbapenemase-producing A. baumannii.