Investigation of a pseudo-outbreak of Myroides odoratimimus in high-dependency units reveals an environmental reservoir

GENÇ S., Türkoğlu E., İça T., Demirkaya F., PERÇİN RENDERS D.

American Journal of Infection Control, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Publication Date: 2026
  • Doi Number: 10.1016/j.ajic.2026.04.015
  • Journal Name: American Journal of Infection Control
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, CINAHL, EMBASE, MEDLINE
  • Keywords: Health care-associated infection, High-dependency unit, Infection control
  • Kütahya Health Sciences University Affiliated: Yes

Abstract

Background In mid-2025, a sudden increase in urinary isolates of Myroides spp, was observed in high-dependency units (HDUs) of a tertiary-care hospital. This study aimed to determine whether the clustering represented sustained transmission or a pseudo-outbreak linked to a common source. Methods A combined retrospective–prospective investigation was conducted in HDUs comprising 8 intensive care units and 1 palliative care unit (total capacity: 89 beds). Seventy-five unique patients with Myroides spp isolated from urine cultures between July 2024 and August 2025 were included. Prospective isolates underwent identification, susceptibility testing, biofilm assessment, rep-PCR, and selected 16S rRNA sequencing. Targeted environmental sampling was performed in units with case clustering. Results A temporal peak occurred in June 2025 (n: 16). All prospectively analyzed isolates were identified as Myroides odoratimimus . Environmental sampling recovered the organism from urine collection containers. rep-PCR analysis of 33 isolates demonstrated a dominant molecular profile shared by 32 isolates, including 29 of 30 clinical isolates and all 3 environmental isolates. Most isolates showed strong biofilm production. After the introduction of single-use urine collection bags, no further isolates were detected. Conclusions These findings indicate a health care-associated pseudo-outbreak linked to an environmental source rather than sustained patient-to-patient transmission.