Impact of Pre-Antibiotic Culture Collection Compliance on Diagnostic Yield and Antimicrobial Resistance Surveillance: A Retrospective Observational Study

Background Obtaining appropriate microbiological cultures before initiation of antimicrobial therapy is a cornerstone of antimicrobial stewardship. Failure to collect cultures before antibiotic administration may reduce diagnostic yield, impair pathogen identification, hinder targeted therapy, and compromise antimicrobial resistance (AMR) surveillance. Despite widespread recommendations, compliance with pre-antibiotic culture collection remains variable across healthcare settings. Objective To evaluate the relationship between pre-antibiotic culture collection compliance, diagnostic yield, and antimicrobial resistance surveillance indicators in a tertiary care hospital. Methods A retrospective observational study was conducted using Antimicrobial Stewardship Program (AMSP) data collected between October 2024 and April 2026. Monthly data on total cultures sent, total isolates recovered, cultures obtained before restricted antibiotic administration, total restricted antibiotic prescriptions, Methicillin-Resistant Staphylococcus aureus (MRSA), Vancomycin-Resistant Enterococcus (VRE), and Carbapenem-Resistant Organisms (CRO) were analyzed. Culture positivity and compliance rates were calculated and trends were evaluated descriptively. Results During the study period, more than 2,000 microbiological cultures were processed. Compliance with pre-antibiotic culture collection varied substantially across months, ranging from approximately 49% to 100%. Culture positivity rates ranged from approximately 24% to 56%. CRO rates demonstrated considerable variation throughout the study period, while MRSA and VRE rates remained consistently low. Higher compliance periods generally demonstrated improved microbiological documentation and enhanced diagnostic stewardship performance. Conclusion Pre-antibiotic culture collection compliance serves as an important diagnostic stewardship indicator. Continuous monitoring of compliance can improve microbiological documentation, support targeted antimicrobial therapy, and strengthen AMR surveillance efforts.