Clinical and microbiological characterization of Starmerella magnoliae in the female genital tract: case report and diagnostic challenges

Background Starmerella magnoliae (formerly Candida magnoliae ) is a rare yeast in clinical practice, sporadically associated with neonatal bloodstream infections, tenosynovitis in immunocompetent individuals, and infections in oncology patients. Its role in female genital tract infections is exceptionally uncommon. Presentation of case We describe a 42-year-old Brazilian woman presenting with genital pruritus and burning. Serological tests for HIV, hepatitis B and C, syphilis, and HPV RT-PCR were negative. Vaginal samples were cultured, identified using the Vitek 2 system (bioMérieux, France), and confirmed by MALDI-TOF MS. Antifungal resistance–associated genes were investigated by polymerase chain reaction.Culture identified S. magnoliae . Metabolic profiling demonstrated assimilation of raffinose, proline, mannose, sorbitol, nitrate, gluconate, and gentiobiose. Molecular analysis detected ERG11 and CDR2 genes associated with antifungal resistance. Empirical oral fluconazole therapy failed to achieve clinical improvement. However, intravaginal nystatin administered for 21 days resulted in complete symptom resolution and negative direct microscopy. Conclusion This case underscores S. magnoliae as a rare cause of vulvovaginal infection, associated with azole resistance markers and poor response to fluconazole. Accurate identification using advanced microbiological and molecular methods is essential to guide appropriate therapy in uncommon infections.