Rhodotorula spp. in Laboratory and Veterinary Clinical Practice: Contamination or an Emerging Problem?

Rhodotorula spp. are ubiquitous red-pigmented yeasts increasingly reported as opportunistic animal pathogens. Recognition matters because underdiagnosis can misguide therapy, especially in companion-animal otitis externa. This review supports laboratory and clinical decisions by summarising taxonomy and ecology, host risk factors, diagnostics, virulence factors, antifungal susceptibility, and veterinary cases. This review addresses: (1) taxonomy and ecology; (2) clinical epidemiology and predisposing factors (immunomodulation, prior antibacterial therapy, chronic inflammation); (3) diagnostics—cytology, organism burden, repeat or pure culture, MALDI-TOF MS, ITS sequencing—with a brief comparison of feasibility in veterinary practice; (4) virulence factors—adhesion and biofilm on abiotic surfaces, hydrolytic enzymes, capsule in some strains, haemolysins, urease, and carotenoids that protect against oxidative stress; (5) antifungal susceptibility and therapy—intrinsic resistance to echinocandins, often high azole MICs, and the most consistent in vitro activity of amphotericin B ± flucytosine; and (6) a synthesis of veterinary case reports. Rhodotorula spp. should not be dismissed as contaminants when clinical signs match laboratory evidence; distinguishing infection from colonisation requires clinicomicrobiological correlation. This review highlights the need for standardised susceptibility testing and veterinary breakpoints, prospective data on burden and outcomes, better data on biofilm behaviour on clinical materials, environmental surveillance, and practical diagnostic and treatment guidance.