Rhodotorula fungemia : Report of two cases in Sfax (Tunisia)

Rhodotorula mucilaginosa Fungemia in an Infected Biloma Patient Following a Traumatic Liver Injury

Rhodotorula mucilaginosa fungemia is rare and highly resistant to antifungal therapy. We herein report a case involving a 31-year-old male admitted after a high-velocity road traffic accident. He sustained a grade IV liver injury with right hepatic vein thrombosis, which necessitated an urgent laparotomy. Post-operatively, repeated imaging of the abdomen revealed the presence of a biloma. Percutaneous subdiaphragmatic drainage was carried out but appeared ineffective, prompting a second surgery for an urgent hemi-hepatectomy. The patient was then nursed in the intensive care unit (ICU); however, during his stay in the ICU, he became more sepsis, which was evident by worsening ventilatory support and a rise in septic parameters from the biochemistry parameters. Despite intravenous piperacillin-tazobactam and fluconazole, his septic parameters did not improve and a full septic workup was conducted and was found to be positive for Rhodotorula mucilaginosa from the blood cultures. After discussion with the infectious disease physicians and clinical microbiologists, it was decided to initiate a course of intravenous meropenem and amphotericin B based on minimum inhibitory concentration (MIC) values, considering the patient's extended ICU stay and catheter use. Eventually, after successfully weaning off mechanical ventilation, the patient was discharged from ICU care. This case underscores the necessity of individualized approaches, combining timely imaging, appropriate drainage techniques, and tailored treatments to optimize outcomes for such intricate post-traumatic complications.

Seven years of progress in determining fungal diversity and characterization of fungi isolated from the Japanese Experiment Module KIBO, International Space Station

The International Space Station (ISS) is a closed facility that orbits the earth carrying not only its crew but also microorganisms. We have participated in microbiota analysis projects for the Japanese Experiment Module KIBO (ISS; operations nomenclature: Microbe-I, II, III, and IV) and were in charge of fungal screening. The interior of KIBO was sampled using swabs and microbe detection sheets (MDSs) for fungal detection. The dominant genera obtained by culture were Aspergillus and Penicillium. DNA analyses of the fungal biota using a clone library showed that KIBO was dominated by Malassezia, a fungal inhabitant of human skin. Three fungal species, Aspergillus sydowii, Penicillium palitans, and Rhodotorula mucilaginosa, which grew under microgravity in KIBO were observed under a field emission-scanning electron microscope on the ground. No novel phenotypic characteristics were noted. The results of antifungal susceptibility testing of all isolates did not differ significantly from previous reports of corresponding fungi. In Microbe-I (August 2009), MDSs were culture negative, while in the next stages the CFU of MDSs were 10 for Microbe-II (February 2011), 24 for Microbe-III (October 2012), and 151 for Microbe-IV (February 2015). These results indicated that fungi inside KIBO are increasing and expanding over time, and therefore continuous surveillance is crucial.

Molecular identification, biofilm formation and antifungal susceptibility of Rhodotorula spp

Luliconazole is an imidazole antifungal agent used in topical form for the treatment of onychomycosis and dermatophytosis. In vitro activity of luliconazole against dermatophytes, Candida, black fungi, Fusarium and Aspergillus species have been investigated. Rhodotorula spp. are environmental yeasts and emerged as opportunistic pathogens among immunocompromised patients. Rhodotorula's human infections are usually resistant to treatment with antifungal drugs especially triazoles and echinocandins. The present study aimed at the molecular detection of environmental isolates of Rhodotorula spp. Then, antifungal efficacy of luliconazole was evaluated against isolates and compared to other routine systemic antifungals including; caspofungin, posaconazole, fluconazole, itraconazole, amphotericin B, and voriconazole. The biofilm production of Rhodotorula isolates was also evaluated. In this study, 39 isolates of Rhodotorula spp. were isolated from the environment, detected using molecular methods, and tested against luliconazole. Then, the anti-fungal activity of luliconazole compared with several routine antifungals. Also, biofilm formation by using a crystal violet staining assay was performed. Our finding showed that luliconazole has a very high minimum inhibitory concentration (MIC) value (1-8 µg/ml) against Rhodotorula spp. Besides, 100% of Rhodotorula strains were resistant to caspofungin, followed by fluconazole 94.7% and voriconazole 74.4%. Amphotericin B was demonstrated excellent in vitro activity against this genus. Our result indicated that 59% of Rhodotorula spp. were in the mid-range of biofilm production. Our results indicated that luliconazole does not effective against the genus Rhodotorula. Furthermore, amphotericin B is the best drug against this genus in comparison to caspofungin and other azole drugs.

Aromatic Hydrocarbon Removal by Novel Extremotolerant Exophiala and Rhodotorula Spp. from an Oil Polluted Site in Mexico

Since Aromatic hydrocarbons are recalcitrant and toxic, strategies to remove them are needed. The aim of this work was to isolate fungi capable of using aromatic hydrocarbons as carbon sources. Two isolates from an oil polluted site in Mexico were identified through morphological and molecular markers as a novel Rhodotorula sp. and an Exophiala sp. Both strains were able to grow in a wide range of pH media, from 4 to 12, showing their optimal growth at alkaline pH's and are both halotolerant. The Exophiala strain switched from hyphae to yeast morphotype in high salinity conditions. To the best of our knowledge, this is the first report of salt triggering dimorphism. The Rhodotorula strain, which is likely a new undescribed species, was capable of removing singled ringed aromatic compounds such as benzene, xylene, and toluene, but could not remove benzo[a] pyrene nor phenanthrene. Nevertheless, these hydrocarbons did not impair its growth. The Exophiala strain showed a different removal capacity. It could remove the polyaromatic hydrocarbons but performed poorly at removing toluene and xylene. Nevertheless, it still could grow well in the presence of the aromatic compounds. These strains could have a potential for aromatic compounds removal.

Fluconazole Resistance in Isolates of Uncommon Pathogenic Yeast Species from the United Kingdom

The triazole drug fluconazole remains one of the most commonly prescribed antifungal drugs, both for prophylaxis in high-risk patients and also as a second-line treatment option for invasive Candida infections. Established susceptibility profiles and clinical interpretive breakpoints are available for fluconazole with Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis, which account for the majority of infections due to pathogenic yeast species. However, less common species for which only limited susceptibility data are available are increasingly reported in high-risk patients and from breakthrough infections. The UK National Mycology Reference Laboratory performs routine antifungal susceptibility testing of clinical isolates of pathogenic yeast submitted from across the United Kingdom. Between 2002 and 2016, ∼32,000 isolates were referred, encompassing 94 different yeast species. Here, we present fluconazole antifungal susceptibility data generated using a CLSI methodology over this 15-year period for 82 species (2,004 isolates) of less common yeast and yeast-like fungi, and amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and anidulafungin, with members of the Nakaseomyces clade (C. glabrata, Candida nivariensis, and Candida bracarensis). At least 22 different teleomorph genera, comprising 45 species, exhibited high MICs when tested with fluconazole (>20% of isolates with MICs higher than the clinical breakpoint [≥8 mg/liter] proposed for C. albicans). Since several of these species have been reported anecdotally from breakthrough infections and therapeutic failures in patients receiving fluconazole, the current study underscores the importance of rapid and accurate yeast identification and may aid clinicians dealing with infections with rarer yeasts to decide whether fluconazole would be appropriate.

Catheter-related bloodstream infection due to Rhodotorula mucilaginosa with normal serum (1→3)-β-D-glucan level

Rhodotorula species are environmental basidiomycete yeasts that have emerged as a cause of fungemia in immunocompromised hosts. The insertion of a central venous catheter was identified as a major risk factor for Rhodotorula fungemia. Few cases reports have reported (1→3)-β-D-glucan testing at the onset of Rhodotorula mucilaginosa fungemia. We report a case of catheter-related bloodstream infection due to R. mucilaginosa. Serum β-D-glucan level was normal at the onset of the bloodstream infection. It took 5 days to culture the isolate. The patient's fever persisted after empiric treatment with micafungin, and a switch to oral voriconazole immediately resolved the fungemia.

[A skin ulcer infection due to Rhodotorula mucilaginosa in an immunocompromised child]

Human cutaneous infections due to Rhodotorula species as an emerged pathogens yeasts are rarely reported, particularly in skin folds, with the ability to infect immunocompromised as well as immunocompetent patient. In present case, we describe a fungal cutaneous infection due to Rhodotorula mucilaginosa in immunocompromised child, the patient has been diagnosed with retinoblastoma; the diagnosis was established by the cytological and clinical examination. However, the cytological examination found fungal forms. The diagnosis relies on the microbiological analysis of clinical samples but the interpretation of a positive culture should be part of and over all analysis that integrate clinical symptoms and risk factors. Most of cases of infection due to Rhodotorula were associated with central venous catheter in patients who were receiving immunosuppressors and cyotoxic drugs. The antifungal susceptibility testing was done; a fluconazol and ketoconazol showed susceptibles. The patient was treated by combinate antifungal therapy and empirical antimicrobial regimen for prophylaxis.