A New Emerging Threat in Critical Care: Myroides odoratimimus Outbreak in a Tertiary Hospital.

Aims and background: Myroides spp. is an environmental pathogen and causes disease in immunocompromised patients. In this study, we report an outbreak of urinary tract infections (UTIs) caused by Myroides odoratimimus (M. odoratimimus) in a university hospital in Turkey. Methods: A total of 25 M. odoratimimus strains isolated from the clinical samples of 20 patients in our intensive care units and clinics were included in the study. Phenotypic and genotypic identification of isolates was performed using conventional methods, VITEK®-2 automated identification system, Matrix Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry, and 16S-RNA Microbial Diagnosis methods. In addition, the repetitive extragenic palindromic (REP) elements polymerase chain reaction (PCR) assay method was applied for molecular epidemiological analysis. Results: All cases were diagnosed with nosocomial UTI, except for one case diagnosed with nosocomial bacteremia. One of the M. odoratimimus isolates was sensitive to piperacillin/tazobactam (MIC: ≤4 µg/mL), and one isolate was moderately sensitive to cefepime (MIC: 16 µg/mL). Other all M. odoratimimus isolates were resistant to the tested antibiotics beta-lactams, monobactams, carbapenems, aminoglycosides, fluoroquinolones, and sulphonamides. When 10 isolates were evaluated with the REP PCR method, DNA fingerprint similarities were visually determined, and there was a similar DNA pattern among them. The source of Myroides infection could not be identified from the environmental samples. Conclusions: The increasing population of immunosuppressed patients suggests that M. odoratimimus and other opportunistic multi-drug resistant pathogens with resistance to broad-spectrum antibiotics may be encountered more frequently in critical units in future.In order to choose the optimal antibiotic regimen, awareness and an index of suspicion regarding this atypical pathogen are important for rapid identification and appropriate susceptibility testing. Clinical significance: It has been observed that the pathogenicity of M. odoratimimus bacteria has increased recently, and it can not only cause UTIs but more serious manifestations such as sepsis with bacteremia, which can be life-threatening. How to cite this article: Savci U, Eser B, Sungur M, Yildiz SS, Akdogan O, Caliskan S, et al. A New Emerging Threat in Critical Care: Myroides odoratimimus Outbreak in a Tertiary Hospital. Indian J Crit Care Med 2025;29(10):829-838.