Kerstersia gyiorum Isolated and Identified From the External Auditory Meatus of an Immunocompromised Patient: A Case Report and Literature Review.

Kerstersia gyiorum, a rare Gram-negative pathogen first identified in 2003, belongs to the Alcaligenaceae family. Although infrequently reported, it has been isolated from various clinical infections, including wounds, and respiratory tract infections. Our case report highlights an unusual presentation of K. gyiorum in a 13-year-old girl with a complex medical history, associated with external ear pressure ulcers. The unusual, uncommonly identified organism was isolated from an ear swab and identified using MicroScan and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The bacterium exhibited sensitivity to multiple antibiotics but showed notable resistance to aminoglycosides and several common agents, emphasizing the importance of tailored therapy.