P-737. Highly Resistant <i>Myroides</i> Species Infections: Insights from a Comprehensive Case Series and Antibiogram Analysis

Abstract Background Myroides species (spp.) are rare opportunistic gram-negative bacteria that are highly resistant to commonly used empiric antibiotics. Able to survive in natural and hospital environments, these microbes pose a growing risk of resistant nosocomial infections. Here we present a case series and antibiogram of Myroides infections at an academic medical center, highlighting this potential pathogen’s antibiotic sensitivity to aid clinicians in choosing effective antimicrobial therapies. Antibiogram Methods Retrospective chart review of all patients diagnosed with Myroides spp. infection at Henry Ford Health between January 1, 2019 and December 31, 2023. Patient characteristics, treatments, and outcomes were analyzed. An antibiogram of Myroides spp. susceptibility to 10 antibiotics was generated. Results A total of 43 patients (median age 62 yr; range 30-94) presented with 46 Myroides spp. infections. Positive cultures were evenly distributed between hospitalizations (50%) and outpatient (50%) settings. Of the 46 infections, 35 (76%) were in a lower extremity wound. Of the 43 patients, 17 (40%) had sepsis at presentation, including 8 (13%) with Myroides bacteremia. Most Myroides spp. cultures (83%) grew additional organisms, including E. faecalis (34%), S. aureus (21%), Proteus mirabilis (21%), and Pseudomonas spp. (16%). Empiric antibiotics were prescribed in 35/46 cases (76%), mostly vancomycin (17/35) and cefepime (9/35); however, Myroides spp. were sensitive to the empiric agents in only 4 cases (11%). Antibiogram analysis showed 100% susceptibility to meropenem and 0%-50% susceptibility to 9 other agents (Table). A total of 5 (12%) patients died, and 6 patients (14%) required readmission within 1 month of treatment. Conclusion Myroides spp. exhibited significant resistance to most empiric antibiotics. Our antibiogram analysis revealed meropenem as the sole effective empiric antibiotic for this opportunistic pathogen. We recommend the prompt empirical use of meropenem when Myroides spp. are identified on antimicrobial culture. Disclosures All Authors: No reported disclosures