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 (non-invasive 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, non-invasive CRAB, invasive CRE, and non-invasive CRE.
Results: There were 535 patients with CRE (87 invasive, 448 non-invasive) and 279 (78 invasive, 201 non-invasive) 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 non-invasive 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, non-invasive CRAB and non-invasive CRE (p<0.0001, see Figure).
Conclusion: 90-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.
M. E. Sexton,
S. Sukumaran, None
J. T. Jacob, None