Impact of new guidelines for microbiological sampling on antibiotic prescribing patterns in general practice in the North Denmark Region: a retrospective pre-post observational study

Background In April 2024, the Department of Clinical Microbiology at Aalborg University Hospital introduced new guidelines for general practitioners in the North Denmark Region, limiting microbiological culture and susceptibility testing of wound, skin, eye, ear, and throat infections to recurrent cases or treatment failure. While intended to reduce unnecessary testing and optimize resource use, the effect on antibiotic prescribing patterns remains unclear.Objective To characterize and explore the development in requested microbiological cultures and susceptibility testing and antibiotic prescribing patterns in general practice in the North Denmark Region before and after the introduction of the new guidelines. Antibiotic prescribing was also compared with the Central Denmark Region.Materials and methods This retrospective pre-post observational study included data from the Department of Clinical Microbiology on submitted and rejected samples from general practices in the North Denmark Region. Furthermore, number of redeemed antibiotic prescriptions from general practices in both the North and Central Denmark Regions were extracted from the Ordiprax + database (available from the Danish Health Data Authority). Two time periods were compared: pre-guideline (April 2023–March 2024) and post-guideline (April 2024–March 2025). Incidence rates and incidence rate ratios were calculated to assess changes in prescribing patterns.Results Submitted samples decreased by 66.4% following guideline implementation. Antibiotic prescribing in the North Denmark Region decreased slightly (–2.4%), with minor changes in prescribing patterns. Similar changes were observed in the Central Denmark Region.Conclusion The guidelines were effectively adopted but had limited impact on antibiotic prescribing in general practice. Further research should assess clinical outcomes, treatment quality, and long-term effects on antimicrobial resistance.