Microbiological Quality and Stability of Pharmaceutical Products in Europe: Discrepancies, Regulatory Perspectives and Challenges

Microbial contamination in pharmaceutical products poses a significant threat to patient safety and drug efficacy. Despite stringent regulatory frameworks, discrepancies between the European Pharmacopoeia (Ph. Eur.) and the United States Pharmacopeia (USP) complicate standardization. This review examines microbiological contamination trends in pharmaceutical recalls from 2020 to 2024, identifies common contaminants, and evaluates rapid microbiological detection methods and alternative antimicrobial strategies. A cross-sectional study of all current recalls, market withdrawals, and safety alerts published by the European competent authorities pertaining to drugs was conducted. A manual review of all the recalls was also conducted to extract additional information including name of product and type, reason for contamination, and responsible contaminant. Contaminant prevalence, sterility compliance issues, and regulatory gaps were analyzed. Differences in microbiological testing methodologies between Ph. Eur. and USP were compared, alongside emerging rapid detection technologies such as Next-Generation Sequencing (NGS) and MALDI-TOF mass spectrometry. Data from recalls in Europe between January 2020 and December 2024 indicate that approximately 70% (N=62) of reported contamination cases lack specific microorganism identification, with Burkholderia cepacia and Ralstonia pickettii being the most frequently reported contaminants. Recalls of sterile pharmaceuticals, including infusion solutions and eye drops, increased significantly in 2023 and early 2024. While traditional sterility testing remains standard, novel technologies such as AI-assisted microbial identification and metagenomics offer promising alternatives for enhanced contamination control. Regulatory harmonization and improved transparency in contamination reporting are essential to mitigate pharmaceutical microbiological risks.