Clinical Features and Outcomes of Myroides Species Infections

Myroides species, Gram-negative bacilli from the Flavobacteriaceae family, are typically considered low-virulence pathogens but have previously been described as extensively drug-resistant. This study investigates the clinical features and outcomes of Myroides infections.

We conducted a retrospective cohort study of patients hospitalized at Cleveland Clinic with Myroides infection. Infections were defined as a positive Myroides culture from a sterile site that were treated with an antibiotic to which the isolate was susceptible. Controls were hospitalized patients with a positive culture for Myroides, who did not meet the definition for infection. Survival for infected patients and uninfected controls was compared using Cox proportional hazards regression.

Between January 2015 and September 2023, 52 positive Myroides species cultures were identified, with 21 deemed infections. A higher proportion of Myroides-infected patients than controls had diabetes mellitus. The most common infections were skin/soft-tissue infections (42.8%), osteomyelitis (33.3%), and urinary tract infections (19%); and 28.5% were bacteremic infections. All isolates were resistant to aminoglycosides, but the majority were susceptible to trimethoprim-sulfamethoxazole (81%), ciprofloxacin (57%), and meropenem (68%). The main antimicrobial treatments provided were meropenem, ciprofloxacin, and trimethoprim-sulfamethoxazole. A significant difference in survival was not found between patients with Myroides infection and uninfected controls (hazard ratio, 3.42; 95% confidence interval, .63-18.74; P = .16).

All patients in this study had reasonable treatment options, belying previous reports of extensive antibiotic resistance in Myroides. Our small study did not detect a statistically significant decrease in survival among Myroides-infected patients compared to controls.