Factors Associated to Prevalence and Incidence of Carbapenem-Resistant Enterobacteriaceae Fecal Carriage: A Cohort Study in a Mexican Tertiary Care Hospital

BACKGROUND Carbapenem-resistant Enterobacteriaceae (CRE) infections have emerged as a serious threat to health worldwide. They are associated with increased morbidity and mortality and are capable of silently colonizing the gastrointestinal tract. Because of this, there is great interest to characterize the epidemiology of CRE carriage and acquisition in healthcare facilities. The aim of this study was to determine the prevalence and factors associated with CRE fecal carriage (CRE-fc), and risk factors for incident cases. METHODS/RESULTS A cohort study was conducted at a tertiary care hospital from January 1st to April 30th, 2014 during a CRE outbreak. Weekly rectal swabs were performed in patients considered at risk until discharge. CRE-fc prevalence was 10.9% (CI 95% 7.7-14.7) among 330 patients. Treatment with carbapenems (OR 2.54, CI 95% 1.15-5.62); transfer from an institution (OR 2.16, CI 95% 1.02-4.59); multi-drug resistant infection within the previous six months (OR 2.81, CI 95% 1.47-5.36); intensive care unit admission (OR 0.42, CI 95% 0.20-0.88); hematologic malignancy (OR 4.02, CI 95% 1.88-8.06); invasive procedures (OR 2.18, CI 95% 1.10-4.32); and sharing a room with a known CRE carrier (OR 3.0, CI 95% 1.43-6.31) were independently associated factors for CRE-fc. Risk factors associated with CRE-fc incidence were determined for 87 patients initially negative and with subsequent screening; the incidence rate was 2.5 cases, per 1000 person-years (CI 95% 1.5-3.9). Independently associated risk factors were carbapenem treatment (HR 2.68, CI 95% 1.03-6.98), hematologic malignancy (HR 5.74, 95% CI 2.46-13.4) and a mean daily colonization pressure ≥10% (HR 5.03, IC 95% 1.77-14.28). OXA-48-like (OXA-232) and CTX-M-15 were the predominantly identified mechanisms of resistance. CONCLUSIONS We found an elevated incidence and prevalence of CRE-fc in our hospital. Hematologic patients need to be considered a population at risk, and antibiotic stewardship along with infection control programs need to be improved to avoid nosocomial spread.