Prophylactic Antimicrobial Prescribing in Australian Residential Aged-Care Facilities: Improvement is Required

Background and Objective Inappropriate antimicrobial use can lead to adverse consequences, including antimicrobial resistance. The objective of our study was to describe patterns of prophylactic antimicrobial prescribing in Australian residential aged-care facilities and thereby provide insight into antimicrobial stewardship strategies that might be required. Methods Annual point prevalence data submitted by participating residential aged-care facilities as part of the Aged Care National Antimicrobial Prescribing Survey between 2016 and 2020 were extracted. All antimicrobials except anti-virals were counted; methenamine hippurate was classified as an antibacterial agent. Results The overall prevalence of residents prescribed one or more prophylactic antimicrobial on the survey day was 3.7% (n = 4643, 95% confidence interval 3.6-3.8). Of all prescribed antimicrobials (n = 15,831), 27.1% (n = 4871) were for prophylactic use. Of these prophylactic antimicrobials, 87.8% were anti-bacterials and 11.4% antifungals; most frequently, cefalexin (28.7%), methenamine hippurate (20.1%) and clotrimazole (8.8%). When compared with prescribing of all antimicrobial agents, prophylactic antimicrobials were less commonly prescribed for pro re nata administration (7.0% vs 20.3%) and more commonly prescribed greater than 6 months (52.9% vs 34.1%). The indication and review or stop date was less frequently documented (67.5% vs 73.8% and 20.9% vs 40.7%, respectively). The most common body system for which a prophylactic antimicrobial was prescribed was the urinary tract (54.3%). Of all urinary tract indications (n = 2575), about two thirds (n = 1681, 65.3%) were for cystitis and 10.6% were for asymptomatic bacteriuria. Conclusions Our results clearly identified immediate antimicrobial stewardship strategies that aim to improve prophylactic antimicrobial prescribing in Australian residential-aged care facilities are required.