Risk factors associated with prolonged intestinal colonization of ESBL-producing Enterobacteriaceae – a prospective cohort study

BACKGROUND: Extended spectrum β-lactamase-producing Enterobacteriaceae (EPE) are responsible for a major part of the widespread antimicrobial resistance (AMR). Increased understanding of risk factors associated with intestinal colonization of EPE is crucial to implement adequate actions against AMR. The aim of this study was to define potential risk factors for prolonged intestinal colonization with EPE. A secondary aim was to analyze if patients were adequately informed about being infected or colonized by antibiotic-resistant bacteria. METHODS: Patients with a positive clinical EPE culture from urine, blood or feces were recruited in a region in the south of Sweden. Selective EPE fecal cultures were obtained at least three months after the initial positive culture. Prolonged intestinal colonization was defined as the prevalence of any EPE in the follow-up fecal sample. Risk factors for prolonged intestinal colonization were evaluated by using a questionnaire and by retrospective review of medical records. A univariate model and a multivariate regression analysis were performed to identify possible risk factors for intestinal EPE colonization. RESULTS: Out of 143 patients included in the study, 57% remained positive for EPE at the second sampling. In a multivariate regression model, urological intervention, history of EPE infection and travel to Africa and/or Asia within 2 years were found to be significantly associated with prolonged intestinal colonization of EPE. Before being approached by us, 50% of patients displayed inadequate knowledge of EPE infection or colonization. CONCLUSION: In this prospective cohort study, urological intervention within 6 months and a history of EPE infection are independently associated with prolonged intestinal colonization with EPE. In contrast, travel to Africa and/or Asia within 2 years is associated with a decreased risk of prolonged intestinal colonization with EPE. There is room for improvement when it comes to patient information regarding EPE to decrease of spread.