Temporal Changes in Microbial Etiology and Antibiotic Resistance Profiles of Osteoarticular Infections: An 11-Year Retrospective Analysis

Abstract

Background: Osteoarticular infections (OAIs) represent a serious clinical concern. Their management is complicated by shifting microbiological landscapes and rising antimicrobial resistance. This study aims to define the long-term trends in pathogen distribution and resistance patterns to guide empirical therapy. Methodology: An 11-year retrospective study (2013-2023) was conducted at Ibn Tofail University Hospital, affiliated with Mohammed VI University Hospital in Marrakech, Morocco. Bacterial isolates from deep osteoarticular samples were identified using standard methods. Antimicrobial susceptibility testing was performed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Statistical analysis was applied to determine significant trends over time. Results: Among 813 bacterial isolates, Gram-negative bacilli predominated (574/813, 70.6%), followed by Gram-positive cocci (239/813, 29.4%). Enterobacteriaceae were the most prevalent pathogens (415/813, 51.05%), with Enterobacter spp. as a major representative, showing an inverse epidemiological trend with Staphylococci. A significant decline in isolates occurred during the COVID-19 pandemic. Enterobacteriaceae exhibited statistically significant increasing resistance to amoxicillin-clavulanate (21/37, 56.75% → 17/25, 68%), third-generation cephalosporins (10/37, 27% → 9/25, 36%), ertapenem (4/37, 10% → 4/25, 16%), gentamicin (7/37, 18.91% → 8/25, 32%), and ciprofloxacin (15/37, 40.54% → 13/25, 52%). No colistin resistance was detected. Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae peaked at 35/82 (42.6%) in 2016, while carbapenem-resistant Enterobacteriaceae (CRE) emerged as a critical concern, rising to 3/25 (12%) in 2023. Acinetobacter baumannii demonstrated high but fluctuating imipenem resistance. Methicillin-resistant Staphylococcus aureus (MRSA) incidence was generally low but with a significant peak in 2017; all staphylococcal isolates remained susceptible to glycopeptides. Conclusions: This retrospective longitudinal study identified Enterobacteriaceae as the predominant pathogens in OAIs, coupled with a significant rise in antimicrobial resistance. These findings highlight the critical need to adapt prophylactic and empirical treatment guidelines to contemporary resistance trends to ensure optimal patient outcomes.