Clinical and Microbiological Characteristics and Antimicrobial Susceptibility Patterns of Multidrug-Resistant Myroides Spp. Infections in Intensive Care Units: A Retrospective Study

Abstract

Purpose: Patients in intensive care units are at risk of infections caused by multidrug-resistant (MDR) pathogens, including theopportunistic bacterium Myroides spp. This study aimed to describe the clinical and microbiological characteristics of MDR Myroidesspp. infections and to report antimicrobial susceptibility patterns and treatment approaches used in clinical practice.Methods: In this retrospective single-center study, 70 patients hospitalized in a tertiary care center in Türkiye between 2017 and 2023who met criteria for true infection were included, although Myroides spp. was isolated from 509 clinical specimens. Demographic,clinical, and laboratory data were analyzed descriptively. Bacterial identification and antimicrobial susceptibility testing wereperformed using the VITEK® 2 GN system on specimens obtained from blood, urine, wound swabs, and invasive procedures.Results: The isolates demonstrated high levels of resistance to most conventional antibiotics tested. Tigecycline showed the highestin vitro susceptibility rate, with 95.2% of isolates classified as susceptible. Tigecycline was also the most frequently used antimicrobialagent in clinical management, with a mean treatment duration of 10.3 days. The mean patient age was 72.7 years, and tigecyclinetreatment was administered to 88.5% of the patients. Most infections involved the urinary tract, while one patient developed invasivedisease with concurrent bacteremia and pneumonia.Conclusion: MDR Myroides spp. infections remain rare but clinically relevant in intensive care settings. The high in vitrosusceptibility observed for tigecycline and its frequent use in treatment highlight its potential role in the management of theseinfections. However, further studies with comparative designs are needed to better define optimal therapeutic strategies.