Frequency of and risk factors for carbapenem-resistant Enterobacteriaceae

Introduction. Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent threat in the USA and are associated with adverse clinical and economic outcomes. Several studies have evaluated risk factors for acquiring CRE versus carbapenem-susceptible Enterobacteriaceae, identifying antibiotic use and length of hospital stay as major players. However, no studies have compared risk factors for CRE colonization versus infection.Hypothesis/Gap Statement. Patients with CRE infection will have different risk factors and worse clinical outcomes than patients with CRE colonization.Aim. To assess clinical outcomes in patients with CRE infection versus CRE colonization.Methodology. A retrospective cohort of adult patients admitted between 1 June 2013 and 31 July 2018 with the first positive CRE culture from any source was performed. Patients were divided into two groups: CRE infection versus CRE colonization. Data collected included demographics, comorbidities, past antimicrobial usage and clinical outcomes (length of stay, in-hospital mortality). The primary outcome was infection-related length of stay. Data analysis was performed utilizing SPSS with a two-sided P value of less than 0.05 considered statistically significant.Results. A total of 56 patients were included (32 with infection; 24 with colonization). Baseline characteristics were similar between both groups. Infected patients were more likely to have higher actual body weight compared to colonized patients (P=0.03). CRE-infected patients had a longer infection-related hospital stay [12 days (5-20) and 7.5 days (1-13), respectively; P=0.08], but in-hospital mortality was similar between infected and colonized patients (37.5 and 29.2 %, respectively; P=0.30). Patients with infection were more likely to have previous exposure to levofloxacin (P=0.02) and trimethoprim/sulfamethoxazole (P=0.03) for a median of 9 days compared to those with colonization. The most common source of CRE in infected patients was the blood compared to respiratory sources in colonized patients.Conclusion. CRE infection as opposed to colonization was more common in patients with previous exposure to levofloxacin and trimethoprim/sulfamethoxazole and those with higher actual body weight.