2410. Clinical Outcomes Associated With Various Treatment Options for Infections Caused by Carbapenem-Resistant Enterobacteriaceae

BACKGROUND: Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) have been designated an urgent level threat to public health. With the advent of novel β lactam/β-lactamase inhibitor combinations, the armamentarium against CRE is expanding. Our study aims to evaluate clinical outcomes in patients with CRE infections. METHODS: A retrospective study was conducted to compare clinical outcomes in adult patients with documented CRE infections between January 2009 and December 2017 and received either ceftazidime–avibactam (CAZ-AVI) or best available therapy (BAT). Best available therapy was defined as antimicrobials with susceptibility to the causative pathogen according to CLSI breakpoints. The following clinical outcomes were assessed: clinical cure, total length of stay (LOS), 30-day mortality, and infection-related mortality. RESULTS: One hundred and fifty patients met criteria for inclusion; 25 in the CAZ-AVI group and 125 in the BAT group. The median Charlson Comorbidity Index (CCI) was 6 in both cohorts, indicating a low baseline probability for survival. The most common primary sites of infection for the CAZ-AVI and BAT cohorts, respectively, were the following: blood (24% vs. 18%, P = 0.580), urine (36% vs. 23%, P = 0.209), intraabdominal (16% vs. 14%, P = 0.754), and lung (12% vs. 27%, P = 0.132). Combination therapy was utilized in 8% of patients in the CAZ-AVI group compared with 42% in the BAT group. Combinations in the BAT group consisted of colistin-based (68%), tigecycline-based (13%), and aminoglycoside-based (13%) regimens. Although clinical cure rates were similar between both groups (80% vs. 72%, P = 0.469), there was a statistically significant difference in both all-cause mortality (24% vs. 73%, P = 0.006) and infection related mortality (4% vs. 26%, P = 0.017) in the CAZ-AVI and BAT groups, respectively. There was a trend toward a lower overall length of stay favoring the CAZ-AVI cohort as opposed to the BAT cohort (16 days vs. 30 days, P = 0.082). CONCLUSION: CAZ-AVI therapy was associated with lower mortality rates for CRE infections and have a high attributable mortality, especially with concomitant bacteremia. Future studies are warranted to confirm these results. DISCLOSURES: All authors: No reported disclosures.