Anatomic, Geographic, and Taxon-Specific Relative Risks of Carbapenem Resistance in the Health Care System of the U.S. Department of Defense.

Carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter spp., and Enterobacteriaceae pose urgent public health threats. The differential burden, relative risks, associations with antimicrobial consumption, and temporal trends of those taxa in large, geographically diverse U.S. health systems remain under reported. Electronic records of all patients in a geographically dispersed 280-hospital managed-care system from 2005 to 2014 were reviewed. Carbapenem-resistant strains were identified based on Clinical and Laboratory Standards Institute guidelines and breakpoints. A total of 360,000 potentially carbapenem-resistant strains were identified from 14.7 million cultures (80% infecting and 20% surveillance). Isolation of bacteria overseas or isolation from the bloodstream was associated with a higher relative risks of carbapenem resistance (CR; P < 0.0001). Enterobacteriaceae were isolated 11 times more frequently than P. aeruginosa and Acinetobacter spp. However, compared to Enterobacteriaceae, the CR levels were 73-fold and 210-fold higher in P. aeruginosa and Acinetobacter spp., respectively. Significant differences in the relative risk of CR between taxa, anatomic, and geographic locations persisted after adjustment for other variables, the biggest differences occurring between taxa. Overall, CR rates increased for Enterobacteriaceae (P = 0.03) and decreased for Acinetobacter spp. and P. aeruginosa (P < 0.0001). These data provide a useful baseline for resistance trending and have implications for surveillance. Infections acquired overseas and bloodstream infections are particularly important areas for continued monitoring.

Epidemiology of Serious Bacterial Infections in Infants Less Than 90 Days in a Military Health System Cohort.

BACKGROUND: Management of suspected serious bacterial infections (SBIs) in infants less than 3 months old is challenging. Understanding the epidemiology of SBI is necessary to inform management decisions. Recent publications have challenged the previously accepted distribution of infections by specimen source and pathogen. We sought to describe the burden of SBIs in previously healthy infants less than 90 days old. METHODS: We conducted a retrospective analysis of the Military Health System database to identify SBI cases among term infants less than 90 days of age from 2005 to 2015. We defined an SBI case as any previously healthy infant with positive cultures for a likely pathogen from blood, urine or cerebrospinal fluid. RESULTS: Of 467,462 live births between January 2005 and September 2015, 3421 infants had positive cultures. After excluding 1781 episodes with isolates considered nonpathogenic or ICD-9 codes for chronic conditions, the overall incidence of SBI was 3.1 cases/1000 live births. The SBI rate dropped from 5.0 cases/1000 live births in 2005 to 2.0 cases/1000 live births in 2015 (P < 0.001 for trend). The most common pathogen was Escherichia coli (51.3%). CONCLUSIONS: In this retrospective review of 467,462 live births, the incidence of SBI decreased from 5.0/1000 to 2.0/1000 live births over time. We identified no cases of Listeria monocytogenes. These data can help inform decisions related to treatment and management of infants with suspected bacterial infections.