<i>Yokenella regensburgei</i> : Infection in an immunocompetent patient

Yokenella regensburgei is an infrequently encountered member of the Enterobacter ales and is rarely implicated in human disease, which often leads to diagnostic uncertainty in routine clinical microbiology laboratories. Reports of infection due to this organism remain scarce, particularly among immunocompetent individuals. We describe the case of a 52-year-old male who presented with a chronic, non-healing ulcer of the left great toe in the absence of any known immunosuppressive condition. Microbiological evaluation of a biopsy specimen from the ulcer yielded a Gram-negative bacillus, which was identified as Y. regensburgei using conventional biochemical testing and confirmed by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility testing was performed to guide targeted therapy. The patient was treated with appropriate antibiotics, following which complete clinical resolution of the ulcer was observed. This report underscores the ability of Y. regensburgei to cause clinically significant skin and soft-tissue infection in immunocompetent hosts and highlights the importance of accurate laboratory identification of rare Enterobacter ales to ensure timely and effective management, particularly in resource-limited settings.