Multidrug-resistant and Extensively Drug-resistant Enterobacteriaceae: Prevalence, Treatments, and Outcomes: A Retrospective Cohort Study

Abstract Background. Highly resistant gram-negative bacteria (GNB) is a global public health threat, especially in intensive care units (ICU). The purpose of this study is to explore the prevalence of drug resistant Enterobacteriaceae infections at an Intensive Care Unit (ICU) in Saudi Arabia. It also aims to assess the appropriateness of therapies used and whether these therapies improved clinical outcomes. Methods. A retrospective study was conducted from 2015 to 2018 in a tertiary hospital ICUs in Saudi Arabia. Positive cultures for multidrug-resistant (MDR), extensive drug resistant (XDR), and pan drug-resistant (PDR) Enterobacteriaceae: Klebsiella pneumoniae (K. pneumonia), Escherichia coli (E. coli), and Enterobacter species were included. Primary outcome was microbiological cure and 30 days in hospital mortality rates; while secondary outcome was length of hospital stay (LOS). Regression models were used to assess the relationship between appropriateness of therapy and outcomes. Results. This study included 227 Enterobacteriaceae cultures in which 60% were either MDR (n=130) or XDR (n=8) infections; no PDR Enterobacteriaceae cultures were identified. The average subjects’ age was 60.1±17.7 years and 54% were females. Half of the MDR/XDR cultures were E. coli, followed by 33% K. pneumoniae, and 16% Enterobacter infection. The most common antibiotics used were piperacillin/tazobactam (53%), followed by carbapenems (47%) and cephalosporins (21.3%). Antibiotic therapy was considered appropriate in 85 out of 138 (61.59%) subjects only. In-hospital death was 84%, microbiological cure rate was achieved in 40% of cases, and the average LOS was 27 days. Appropriateness of antibiotic therapy prescribed was not a predictor of any of the study clinical outcomes. Conclusion. In this study, there was a high prevalence of resistant Enterobacteriaceae infections, which were associated with a high mortality rate. This warrants the need to assess the effectiveness of antimicrobial stewardship program and infection prevention and control practices particularly in critically ill patients.