Implementation of contact isolation strategy for the containment of extended-spectrum ß-lactamase carriers in a University Hospital positively affects the epidemiology of carbapenemase-producing Enterobacterales.

ABSTRACT

INTRODUCTION: The lack of consensus of control measures to prevent extended-spectrum ß-lactamase producing Enterobacterales (ESBL-E) transmission in the hospital setting is of great concern. We describe the prevalence and species distribution of ESBL-E and carbapenemase producing Enterobacterales (CPE) in patients admitted in a tertiary Hospital during an active surveillance screening program for detecting ESBL-E carriers and reducing the ESBL-E transmission (R-GNOSIS Project). METHODS: From March-2014 to March-2016, 15,556 rectal swabs were collected from 8209 patients admitted in two medical (Gastroenterology, Pneumology) and two surgical (Neurosurgery, Urology) wards. Swabs were seeded onto ChromoID-ESBL and -CARB/OXA-48 agar plates. Growing colonies were identified by MALDI-TOF MS. ESBL and carbapenemases were phenotypically detected. Changes in species diversity (SDI) and distribution over time were analyzed. RESULTS: ESBL-E incidence (8.4%) tended to decrease over time (p=0.003) and CPE carrier prevalence remained unchanged during the study (2%). The contact isolation strategy targeted to reduce ESBL-E transmission was ineffective in reducing ESBL-E carriers but significant differences were observed with CPE (p=0.017). SDI did not change among ESBL-E and E. coli was predominant (78.5%) during the study. K. pneumoniae (54%) was the most frequent CPE species, followed by E. coli (19%). SDI decreased among the CPE population over time mainly due to K. pneumoniae dominance and increased E. coli prevalence in the last part of the study. CONCLUSIONS: During the R-GNOSIS project, contact precautions were not effective in reducing the ESBL-E transmission but may have had a positive collateral effect on the CPE containment.