Epidemiology of Rhodotorula: An Emerging Pathogen

Section of Infectious Diseases, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul Ramiro Barcelos 2350, 90640-002 Porto Alegre, RS, Brazil.
Interdisciplinary Perspectives on Infectious Diseases 10/2012; 2012:465717. DOI: 10.1155/2012/465717
Source: PubMed

ABSTRACT This is an updated paper focusing on the general epidemiological aspects of Rhodotorula in humans, animals, and the environment. Previously considered nonpathogenic, Rhodotorula species have emerged as opportunistic pathogens that have the ability to colonise and infect susceptible patients. Rhodotorula species are ubiquitous saprophytic yeasts that can be recovered from many environmental sources. Several authors describe the isolation of this fungus from different ecosystems, including sites with unfavourable conditions. Compared to R. mucilaginosa, R. glutinis and R. minuta are less frequently isolated from natural environments. Among the few references to the pathogenicity of Rhodotorula spp. in animals, there are several reports of an outbreak of skin infections in chickens and sea animals and lung infections and otitis in sheep and cattle. Most of the cases of infection due to Rhodotorula in humans were fungemia associated with central venous catheter (CVC) use. The most common underlying diseases included solid and haematologic malignancies in patients who were receiving corticosteroids and cytotoxic drugs, the presence of CVC, and the use of broad-spectrum antibiotics. Unlike fungemia, some of the other localised infections caused by Rhodotorula, including meningeal, skin, ocular, peritoneal, and prosthetic joint infections, are not necessarily linked to the use of CVCs or immunosuppression.

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    ABSTRACT: To describe a case of fungal keratitis involving an atypical organism with confirmatory in vivo confocal microscopy and to review the literature on Rhodotorula keratitis. Case report and review of the medical literature. A 22-year-old college student was struck in the left eye with a tree branch and subsequently developed pain, redness and photophobia. Upon presentation, visual acuity was 20/200 and there was a large epithelial defect with diffuse stromal inflammation involving the anterior one-third of the cornea. Cultures of the infiltrate were performed for bacterial, viral and fungal organisms that resulted in a positive culture for Rhodotorula mucilaginosa. Fungal elements were confirmed in vivo by confocal microscopy. The patient was treated with voriconazole initially and had amphotericin added once Rhodotorula infection was confirmed. The patient responded well clinically, and one month after therapy was initiated, the corneal infiltrate had resolved leaving mild anterior stromal haze. Upon completion of therapy at three months, the patient was asymptomatic, had a clear cornea and had a best corrected visual acuity of 20/20 in the involved eye. There was no measurable change in his manifest refraction. Prior cases of Rhodotorula keratitis most often required surgical intervention and were associated with poor outcomes. This case shows that Rhodotorula keratitis can be successfully treated with topical antifungal agents if diagnosed early and appropriate treatment is initiated promptly. We report the first case of Rhodotorula keratitis confirmed by in vivo confocal microscopy. This is also the first description of pseudomycelium formation that has not been previously described in vivo, a morphological structure that this organism rarely demonstrates. Finally, this case shows that confocal microscopy may aid in the early diagnosis and management of fungal keratitis involving this rare but potentially damaging organism.
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