Comparison of 30- and 90-Day Mortality Rates in Patients with Cultures Positive for Carbapenem-resistant Enterobacteriaceae and Acinetobacter in Atlanta, 2011–2015

Abstract

Abstract Background Carbapenem-resistant Enterobacteriaceae (CRE) and Acinetobacter baumannii (CRAB) pose a threat to public health, but comparisons of disease burden are limited. We compared survival in patients following cultures positive for CRE or CRAB. Methods The Georgia Emerging Infections Program performs active population-based and laboratory-based surveillance for CRE and CRAB in metropolitan Atlanta, GA. Using standard CDC definitions, we included patients who had incident carbapenem-nonsusceptible E. coli, Klebsiella spp., Enterobacter spp., or Acinetobacter baumannii isolated from urine only (noninvasive infection) or a sterile site (invasive infection) between 8/2011 and 12/2015. Death dates, verified by Georgia Vital Statistics records, were used to calculate 30- and 90-day mortality rates. We used the chi-square test for mortality rates and the log-rank test for survival analysis to 90 days to compare patients with invasive CRAB, noninvasive CRAB, invasive CRE, and noninvasive CRE. Results There were 535 patients with CRE (87 invasive, 448 noninvasive) and 279 (78 invasive, 201 noninvasive) with CRAB. Nearly all patients with CRE and CRAB had healthcare exposures (97.2% vs. 100%) and most were immunosuppressed (62.6% vs. 56.3%). Both 30-day (24.4% vs. 18.3%, p = 0.04) and 90-day (37.6% vs. 30.5%, p = 0.04) mortality were higher in patients with CRAB than CRE. Patients with invasive infections were more likely to die at 90 days than those with noninvasive infections (53.3% vs. 38.4%, p < 0.0001). Overall mortality rates for invasive infection were similar between CRAB and CRE at 30 (44.9% vs. 34.5% p = 0.2) and 90 days (59.0% vs. 48.3%, p = 0.2). Using survival analysis at 90 days, invasive CRAB had the worst outcomes, followed by invasive CRE, noninvasive CRAB and noninvasive CRE 
(p < 0.0001, see Figure). Conclusion Ninety -day mortality for invasive infections with CRE and CRAB was ~50%, and patients with CRAB had lower survival than those with CRE, suggesting that prevention efforts may need to prioritize CRAB as highly as CRE in facilities with endemic CRAB. With the high proportion of healthcare exposures and immunosuppression, these infections may signify poor prognosis or directly contribute to mortality. Disclosures All authors: No reported disclosures.