1669. A US Based National Surveillance Study for the Susceptibility and Epidemiology of <i>Clostridioides difficile</i> Associated Diarrheal Isolates with Special Reference to Ridinilazole: 2020-2021

Abstract Background We have previously reported on a US based national surveillance study from 6 geographically dispersed medical centers for the susceptibility and epidemiology of C. difficile isolates. This current survey was conducted with isolates collected in 2020-21 specific attention to ridinilazole as well nine comparators. A summary susceptibilities 300 tested against 10 antimicrobial agents Methods or stools patients toxin positive antibiotic associated diarrhea were referred central lab. After confirmation determined by agar dilution method (CLSI M11-A9) listed Table below. Ribotyping performed PCR capillary gel electrophoresis all Results are shown Table. The most common ribotype 014-020 (14.4% compared 11.8% 2016), followed 106 (10%, 15% 027 (10% 13.1% 002 (8% 8.5% 2016, 078-126 (4.3% 1.3% 2016). Ridinilazole very potent an MIC 90 0.25 mcg/ml, including hypervirulent ribotypes those resistances other antibiotics test panel. Conclusion showed excellent in-vitro activity US, independent ribotype. There has been striking change distribution accompanied reduction resistance moxifloxacin imipenem. Disclosures Cheleste M. Thorpe, MD, Actelion: Grant/Research Support|Deinove: Advisor/Consultant|General Mills: Support|Merck: Support|Pfizer: Support|Summit: Advisor/Consultant|Summit: Support Stuart Johnson, M.D., Ferring Pharmaceuticals: Membership Publication Steering Committee|Ferring Employee|Summit Plc: Advisor/Consultant Dale N. Gerding, Destiny Pharma plc.: Karen Carroll, Abbott Diagnostics: Advisor/Consultant|BD Support|BioRad, Inc: Support|Meridian Biosciences: Support|Roche Advisor/Consultant|Scanogen, Support|Thermo Fisher, Kevin W. Garey, PharmD, MS, Acurx: Support|cidara: Advisor/Consultant|cidara: Support|Paratek: Support|Seres Health: Esther Duperchy, PhD, Summit Employee David R. Snydman, Merck: Advisor/Consultant|Merck Company: Support|Prolacta: Advisor/Consultant|Prolacta: Support|Seres: Advisor/Consultant|Seres Support|Summit Support|Takeda: Advisor/Consultant|Takeda: Support|Visterra: Advisor/Consultant.