389: Trends in Coagulase-Negative Staphylococcal Resistance: An Emerging Concern in Bloodstream Infection

Introduction: Coagulase-negative staphylococci (CoNS), once regarded primarily as contaminants, have emerged as significant nosocomial pathogens, especially in central line-associated bloodstream infections (CLABSIs), prosthetic device infections, and immunocompromised hosts. Despite their increasing clinical relevance, CoNS often remain underreported in stewardship discussions. We analyzed 10 years of longitudinal susceptibility data to characterize evolving resistance patterns in CoNS isolated from blood cultures at a community hospital. Methods: We conducted a retrospective observational analysis of our institutional antibiograms from 2013 to 2023, focusing on CoNS species recovered from blood cultures. Susceptibility rates were extracted for oxacillin, vancomycin, linezolid, gentamicin, levofloxacin, and rifampin. Oxacillin resistance was used for methicillin resistance and biofilm-forming potential. Trends were assessed using linear regression and chi-square testing, focusing on antibiotics relevant to device-associated infections. Results: Over the study period, CoNS isolates showed persistently high oxacillin resistance (50–72%) with a significant upward trend (p=0.04). Susceptibility to gentamicin declined from 72% to 58% (p=0.03), and levofloxacin from 87% to 71% (p=0.02). Rifampin and linezolid retained excellent activity (≥97%), while vancomycin susceptibility remained universal. Tetracycline and TMP-SMX susceptibilities fluctuated without a consistent trend. From 2020 to 2023, CoNS represented 8–10% of bloodstream isolates, underscoring their continued clinical significance. Conclusions: CoNS are a persistent and increasingly resistant cause of bloodstream infections, particularly in device-associated settings. Rising resistance to oxacillin, gentamicin, and fluoroquinolones highlights the need to consider these organisms in empiric coverage, especially for high-risk patients. The preserved activity of vancomycin, rifampin, and linezolid supports their continued use in targeted therapy, but rising methicillin resistance underscores the limitations of beta-lactams in empiric regimens. Ongoing surveillance and inclusion of CoNS in stewardship efforts are warranted. This study is limited by its retrospective, single-center design and lack of species-level data, which may affect generalizability.