What is the evidence base of used aggregated antibiotic resistance percentages to change empirical antibiotic treatment? A scoping review

Objectives Antibiotic resistance requires continuous monitoring by experts to decide whether empirical antibiotic therapies (EATs) should be replaced by alternative antibiotics. The exact moment and criteria for this change are unclear and generally based on consensus between experts. This scoping review aims to identify from the literature the resistance thresholds used for a change in EAT and the criteria on which they are based. Methods Scoping review for which a comprehensive structured literature search was conducted. Rayyan, software for systematic reviews, was used for the screening of abstracts and titles. Data sources were Pubmed and a hand-search of reference lists and grey literature. Papers were eligible if they concerned any type of bacterial infectious disease and mentioned or defined antibiotic resistance thresholds for decision-making purposes for EAT. The inclusion and analysis of articles was done by two researchers; any conflicts were resolved through discussion or by consulting a third reviewer. Results We identified 3146 unique papers. Following title/abstract screening, 125 papers were comprehensively read, and 16 papers were included. The included papers gave thresholds for urinary tract infections, respiratory tract infections, meningitis, skin and soft tissue infections, gonorrhoea, and bone and joint infections. Six criteria were found that were commonly used to base the thresholds on. These were: disease severity, efficacy of treatment, adverse drug events, risk of Clostridioides difficile infection, costs, and increased resistance. The number of criteria used to define each threshold varied from one to six between papers. Conclusions The thresholds used for EATs are few, commonly based on expert opinion estimates, and can therefore have broad ranges. Used criteria underlying reported thresholds are heterogenous and require standardization. Considering the rising trend in resistance, there is a clear need for rigid tools to determine thresholds in order to support guideline development with the best and timely evidence.