First documented isolation of Diutina mesorugosa (Candida mesorugosa) from a clinical sample in Argentina.

Recent advances in molecular phylogenetic and revisions to the International Code of Nomenclature have led to major changes in the fungal taxonomy. Genus Candida has been subject to extensive reclassification, with ribosomal DNA analysis demonstrating that Candida rugosa represents a cryptic species complex. Consequently, these taxa were reassigned to the novel genus Diutina. The Diutina rugosa complex includes species morphologically and physiologically indistinguishable: D. rugosa, D. mesorugosa, D. neorugosa, and D. pseudorugosa. We report the first case of D. mesorugosa diagnosed in Argentina in a 51-year-old man patient with complete spinal cord syndrome who developed osteomyelitis associated with sacrogluteal pressure ulcers. The yeast was isolated from bone tissue alongside ESBL-producing Proteus mirabilis. Fungal identification was confirmed using ribosomal DNA sequencing. D. mesorugosa is an emerging opportunistic pathogen that affects immunocompromised individuals. The patient responded favorably to a three-month course of oral fluconazole and combination antibiotic therapy (meropenem/ertapenem) for the bacterial co-infection.