Impact of an antimicrobial stewardship programme on antimicrobial utilization and the prevalence of MDR Pseudomonas aeruginosa in an acute care hospital in Qatar

Background The excessive and inappropriate use of antibiotics is universal across all healthcare facilities. In Qatar there has been a substantial increase in antimicrobial consumption coupled with a significant rise in antimicrobial resistance (AMR). Antimicrobial stewardship programmes (ASPs) have become a standard intervention for effective optimization of antimicrobial prescribing. Methods A before-after study was conducted in Hamad General Hospital (603 bed acute care hospital): 1 year before implementation of a comprehensive ASP compared with the following 2 years. The ASP included a hospital-wide pre-authorization requirement by infectious diseases physicians for all broad-spectrum antibiotics. Prevalence of MDR Pseudomonas aeruginosa was compared with antimicrobial consumption, calculated as DDD per 1000 patient-days (DDD/1000 PD). Susceptibility was determined using broth microdilution, as per CLSI guidelines. Antibiotic use was restricted through the ASP, as defined in the hospital's antibiotic policy. Results A total of 6501 clinical isolates of P. aeruginosa were collected prospectively over 3 years (2014-17). Susceptibility to certain antimicrobials improved after the ASP was implemented in August 2015. The prevalence of MDR P. aeruginosa showed a sustained decrease from 2014 (9%) to 2017 (5.46%) (P = 0.019). There was a significant 23.9% reduction in studied antimicrobial consumption following ASP implementation (P = 0.008). The yearly consumption of meropenem significantly decreased from 47.32 to 31.90 DDD/1000 PD (P = 0.012), piperacillin/tazobactam from 45.35 to 32.67 DDD/1000 PD (P < 0.001) and ciprofloxacin from 9.71 to 5.63 DDD/1000 PD (P = 0.015) (from 2014 to 2017). Conclusions The successful implementation of the ASP led to a significant reduction in rates of MDR P. aeruginosa, pointing towards the efficacy of the ASP in reducing AMR.