Epidemiology and Outcome of Rhodotorula Fungemia in a Tertiary Care Hospital

Fungal profile, levels of aflatoxin M1, exposure, and the risk characterization of local cheese 'wagashi' consumed in the Ho Municipality, Volta Region, Ghana

Wagashi is a West African type cottage cheese locally prepared from cow milk. Wagashi like other milk products, is prone to microbial contamination, particularly by fungi. Many of these fungal species produce mycotoxins which are of serious public health concern. This work aimed to update the mycoflora profile and determine the concentrations of aflatoxin M1 and its health risk characterization due to the consumption of wagashi. Culturing the wagashi on mycological media (Oxytetracycline Glucose Yeast Extract OGYE, Dichloran Rose Bengal Chloramphenicol DRBC) caused a de-novo growth of the quiescent spores at 28-30 °C for 5-7 days. The analysis of AFM1 levels in the samples was done using High-Performance Liquid Chromatography connected to a Fluorescence detector (HPLC-FLD). The exposure and risk assessment to the AFMI levels were determined using deterministic models prescribed by the European Food Safety Authority (EFSA). The fungal counts ranged between 2.36-4.30 log10 CFU/g. In total, thirteen (13) fungal species from eight (8) genera were isolated from all wagashi samples. They are; Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, Fusarium verticillioides, Penicillium digitatum, Trichoderma harzianum, Aspergillus terreus, Rhodotorula mucilaginosa, Rhizopus stolonifer, Aspergillus fumigatus, Yeast sp., Mucor racemosus and Fusarium oligosporum belonging to the genera Fusarium, Aspergillus, Penicillium, Trichoderma, Rhodotorula, Rhizopus, Yeast, and Mucor. The AFM1 observed in the wagashi samples' analysis was low, ranging from 0.00 (Not Detected) ± 0.00 - 0.06 ± 0.002 µg/Kg. Risk assessments of AFM1 using deterministic models produced outcomes that ranged between 5.92 × 10-3- 0.14 ng/kg bw/day, 1.42 -44.35, 0-0.0323 ng aflatoxins/kg bw/day, and 1.51 × 10-3 - 9.69 × 10-4 cases/100,000 person/yr for estimated daily intake (EDI), margin of exposure (MOE), average potency, and cancer risks, respectively, for the age categories investigated. Fungal counts were interpreted as medium to high. It was also established that the consumption of wagashi may pose adverse health effects on all age categories in the selected zones of the study since all calculated MOE values were less than 100,000.

Emerging Fungal Pathogen Rhodotorula Species Isolated From a Patient With a Lung Malignancy

Rhodotorula is a genus of ubiquitous pigmented yeast found in the environment and as a commensal of human and animal microbiota. Previously considered nonpathogenic, Rhodotorula has emerged as an important cause of nosocomial and opportunistic infections in susceptible patients. While Rhodotorula spp. are common commensals in healthy individuals, the yeast may overgrow in patients with compromised immune systems causing disease. Herein, we provide a detailed presentation of a rare case involving a 79-year-old Caucasian female with a lung malignancy who developed massive cavitations in her lungs. The patient's lung tissue was cultured and grew an unidentified species of the genus Rhodotorula. The patient's health declined rapidly, and she expired due to hypoxemia. Clinicians must recognize patient groups potentially at risk for infection with Rhodotorula spp. Early identification and initiation of appropriate interventions are crucial in reducing mortality associated with this opportunistic fungal infection.

Rare Yeasts in Latin America: Uncommon Yet Meaningful

Systemic infections caused by rare yeasts are increasing given the rise in immunocompromised or seriously ill patients. Even though globally, the clinical significance of these emerging opportunistic yeasts is increasingly being recognized, less is known about the epidemiology of rare yeasts in Latin America. This review collects, analyzes, and contributes demographic and clinical data from 495 cases of infection caused by rare yeasts in the region. Among all cases, 32 species of rare yeasts, distributed in 12 genera, have been reported in 8 Latin American countries, with Trichosporon asahii (49.5%), Rhodotorula mucilaginosa (11.1%), and Saccharomyces cerevisiae (7.8%) the most common species found. Patients were mostly male (58.3%), from neonates to 84 years of age. Statistically, surgery and antibiotic use were associated with higher rates of Trichosporon infections, while central venous catheter, leukemia, and cancer were associated with higher rates of Rhodotorula infections. From all cases, fungemia was the predominant diagnosis (50.3%). Patients were mostly treated with amphotericin B (58.7%). Crude mortality was 40.8%, with a higher risk of death from fungemia and T. asahii infections. Culture was the main diagnostic methodology. Antifungal resistance to one or more drugs was reported in various species of rare yeasts.

Rhodotorula mucilaginosa Fungemia, a Rare Opportunistic Infection without Central Venous Catheter Implantation, Successfully Treated by Liposomal Amphotericin B

Background. Fungemia due to Rhodotorula mucilaginosa is rare and highly resistance to antifungal therapy. Since most cases of R. mucilaginosa fungemia are attributed to medical devices, limited information is currently available on infection without central venous catheter (CVC) implantation. We herein report a case of R. mucilaginosa fungemia without implantation of CVC, successfully treated by liposomal amphotericin B (L-AMB). Case Presentation. An 81-year-old man with a history of chronic obstructive lung disease and rheumatoid arthritis was admitted with dyspnea and fever. The present case had no previous history of CVC implantation. Candidemia was suspected based on yeast and salmon-pink colonies in blood cultures, and thus, micafungin (MCFG) was administered. The isolated yeast was identified as R. mucilaginosa, which exhibited resistance to MCFG. Therefore, antifungal therapy was changed to L-AMB. The sterile blood culture and defervescence were observed from the initiation of L-AMB. Conclusion. Although the obvious entry point was unclear, long-term immunosuppressive therapy for RA may have damaged the gastrointestinal tract, which leading to the bacterial translocation of R. mucilaginosa. An early class switch to L-AMB was effective. Physicians need to consider the administration of L-AMB in cases suspected of R. mucilaginosa fungemia following the detection of salmon-pink colonies in blood cultures.

Draft Genome Sequence of Rhodotorula mucilaginosa from an Adult Patient in Qatar

Rhodotorula mucilaginosa is an opportunistic fungal pathogen of public health importance. We present the draft genome sequence of an isolate (Rhodo3571) cultured from an immunocompetent patient. The isolate is similar to other R. mucilaginosa genomes in the NCBI database. Presented here are the genome assembly and its comparison to other reference genomes.

Epidemiological Characterization of Clinical Fungal Isolates from Pauls Stradinš Clinical University Hospital, Latvia: A 4-Year Surveillance Report

Nosocomial fungal infections are an emerging global public health threat that requires urgent attention and proper management. With the limited availability of treatment options, it has become necessary to understand the emerging epidemiological trends, mechanisms, and risk factors. However, very limited surveillance reports are available in the Latvian and broader European context. We therefore conducted a retrospective analysis of laboratory data (2017-2020) from Pauls Stradinš Clinical University Hospital (PSCUH), Riga, Latvia, which is one of the largest public multispecialty hospitals in Latvia. A total of 2278 fungal isolates were analyzed during the study period, with Candida spp. comprising 95% of the isolates, followed by Aspergillus spp. and Geotrichum spp. Amongst the Candida spp., C. albicans and C. glabrata made up about 75% of the isolates. The Department of Lung Diseases and Thoracic Surgery had the highest caseload followed by Intensive Care Department. Majority of the fungal isolates were collected from the bronchoalveolar lavage (37%), followed by urine (19%) and sputum (18%) samples. A total of 34 cases of candidemia were noted during the study period with C. albicans being the most common candidemia pathogen. Proper surveillance of emerging epidemiological trends serve as the most reliable and powerful cornerstone towards tackling this emerging threat.

Central line-associated Rhodotorula mucilaginosa fungemia in an immunocompetent host: Case report and review of the literature

Rhodotorula mucilaginosa is an emerging fungal infection with the ability of biofilms formation. The identification of R mucilaginosa fungemia should trigger reflexes of prompt central venous line removal and using Amphotericin therapy.

Low sensitivity of conventional fungal agars in fungemia by Rhodotorula mucilaginosa: description of two cases

Background

Although most bloodstream yeast infections are caused by Candida spp., infections by rare or less common species have increased in recent years. Diagnosis of infections caused by these species is difficult due to the lack of specific symptoms and adequate diagnostic tools.

Cases presentation

We describe two cases of fungemia by Rhodotorula mucilaginosa within a few months of each other, in a secondary Spanish hospital. In both cases, diagnosis was challenging. Blood subcultures in conventional fungal media were persistently negatives and the use of non-conventional fungal media was essential for isolating the yeasts and achieving a correct diagnosis. 1–3 beta-d-glucan detection and a panfungal PCR assay were helpful techniques to confirm the diagnosis

Conclusion

It is highly important to establish an early diagnosis for fungemia. The process is challenging because often non-specific symptoms are presents. When yeasts grow in blood cultures other genera than Candida spp. could be the cause of infection. Patient risk factors should be assessed to incorporate alternative culture media and the available rapid diagnostic test, in order to provide an early recognition of the pathogen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00427-w.

Evaluation of Rhodotorula spp. contamination in hospital environments

Microbiological monitoring of air and surfaces is a valuable tool for assessing the level of environmental contamination by bacteria and fungi in hospitals, especially in high-risk wards. The presence of these microorganisms requires strict control in view of their role as opportunistic pathogens. As regard yeasts, Candida albicans is one of the main opportunistic pathogens. However, in recent years, many other "non-Albicans" species have been identified that are implicated in the onset of both localised infections in immunocompetent patients and systemic infections in immunocompromised patients. The aim of the work was to evaluate the frequency of isolation of Rhodotorula spp. in environmental samples of hospital origin in order to highlight how its presence may represent an increased risk for hospitalised patients. The samples were taken in at-risk wards, divided into six types of environments, in three hospitals in southern Sardinia between 2016 and 2019. The presence of moulds and yeasts was higher in the air (55.7%) than on surfaces (44.3%) in the hospital environments (p < 0.001). Similarly, the isolation frequency of Rhodotorula spp. was found to be greater (p < 0.001) in the air (14.2%) than on surfaces (9.2%). This study made it possible to evaluate the presence of pathogenic fungi in hospital environments, paying particular attention to Rhodotorula spp. since it is an emerging opportunistic yeast. It also highlights the importance of control measures especially in those where immunocompromised patients are present.

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.

[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.

Tinea capitis-like infection caused by Rhodotorula mucilaginosa in a shelter for African Refugee Children in Northern Israel

Rhodotorula is a genus of unicellular pigmented yeasts, part of the division Basidiomycota. In this article, we report three cases of refugee children in a day care shelter in northern Israel who were clinically diagnosed and treated empirically as with ringworm infection but with clean and exclusive growth of Rhodotorula mucilaginosa in repeated cultures of several skin samples. Skin infections caused by this yeast are rare and there are few reports in the literature, mainly in patients who are immunocompromised. Here we report an infectious process of the scalp in immunocompetent children, caused by Rhodotorula mucilaginosa mimicking tinea capitis.

Synergistic Interactions in Microbial Biofilms Facilitate the Establishment of Opportunistic Pathogenic Fungi in Household Dishwashers

Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.

Rare fungal infectious agents: a lurking enemy

In the expanding population of immunocompromised patients and those treated in intensive care units, rare fungal infectious agents have emerged as important pathogens, causing invasive infections associated with high morbidity and mortality. These infections may present either as de novo or as breakthrough invasive infections in high-risk patients with hematologic malignancies receiving prophylactic or empirical antifungal therapy or in patients with central venous catheters. Diagnosis and treatment are challenging. Physicians should have a high index of suspicion because early diagnosis is of paramount importance. Conventional diagnostic methods such as cultures and histopathology are still essential, but rapid and more specific molecular techniques for both detection and identification of the infecting pathogens are being developed and hopefully will lead to early targeted treatment. The management of invasive fungal infections is multimodal. Reversal of risk factors, if feasible, should be attempted. Surgical debridement is recommended in localized mold infections. The efficacy of various antifungal drugs is not uniform. Amphotericin B is active against most yeasts, except Trichosporon, as well as against Mucorales, Fusarium, and some species of Paecilomyces and dimorphic fungi. The use of voriconazole is suggested for the treatment of trichosporonosis and scedosporiosis. Combination treatment, though recommended as salvage therapy in some infections, is controversial in most cases. Despite the use of available antifungals, mortality remains high. The optimization of molecular-based techniques, with expansion of reference libraries and the possibility for direct detection of resistance mechanisms, is awaited with great interest in the near future. Further research is necessary, however, in order to find the best ways to confront and destroy these lurking enemies.

Future Research Priorities in Fungal Resistance

Improved understanding of basic mycological, pharmacological, and immunological processes has led to important advances in the diagnosis and treatment of invasive fungal infections. However, the rise of fungi that are resistant to existing antifungal agents poses a substantial threat to human health. Addressing this expanding problem is an urgent priority for the international research community. In this article, we highlight important diagnostic and therapeutic advances that address the rise of resistant fungi as well as new public health initiatives that warrant further investigation to help curb the spread of these potentially lethal organisms.

Yeasts

Yeasts are unicellular organisms that reproduce mostly by budding and less often by fission. Most medically important yeasts originate from Ascomycota or Basidiomycota. Here, we review taxonomy, epidemiology, disease spectrum, antifungal drug susceptibility patterns of medically important yeast, laboratory diagnosis, and diagnostic strategies.

Pseudozyma and other non-Candida opportunistic yeast bloodstream infections in a large stem cell transplant center

Non-Candida opportunistic yeasts are emerging causes of bloodstream infection (BSI) in immunocompromised hosts. However, their clinical presentation, management, and outcomes in stem cell transplant (SCT) recipients are not well described. We report the first case to our knowledge of Pseudozyma BSI in a SCT recipient. He had evidence of cutaneous involvement, which has not been previously described in the literature. He became infected while neutropenic and receiving empiric micafungin, which is notable because Pseudozyma is reported to be resistant to echinocandins. He was successfully treated with the sequential use of liposomal amphotericin B and voriconazole. A review of the literature revealed nine reported instances of Pseudozyma fungemia. We performed a retrospective review of 3557 SCT recipients at our institution from January 2000 to June 2015 and identified four additional cases of non-Candida yeast BSIs. These include two with Cryptococcus, one with Trichosporon, and one with Saccharomyces. Pseudozyma and other non-Candida yeasts are emerging pathogens that can cause severe and disseminated infections in SCT recipients and other immunocompromised hosts. Clinicians should have a high degree of suspicion for echinocandin-resistant yeasts, if patients develop breakthrough yeast BSIs while receiving echinocandin therapy.

The Black Yeast Exophiala dermatitidis and Other Selected Opportunistic Human Fungal Pathogens Spread from Dishwashers to Kitchens

We investigated the diversity and distribution of fungi in nine different sites inside 30 residential dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the dishwashers, primarily at the dishwasher rubber seals, at up to 10⁶ CFU/cm²; the other fungi detected were in the range of 10² to 10⁵ CFU/cm². The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium). Comparison of fungal contamination of kitchens without and with dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular) in kitchens with dishwashers. In kitchens without dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with dishwashers, while Saprochaete/Magnusiomyces isolates were only found within dishwashers. We conclude that dishwashers represent a reservoir of enriched opportunistic pathogenic species that can spread from the dishwasher into the indoor biome.

Isolation and Identification of Pathogenic Filamentous Fungi and Yeasts From Adult House Fly (Diptera: Muscidae) Captured From the Hospital Environments in Ahvaz City, Southwestern Iran

Musca domestica L., 1758 is capable of transferring a number of pathogenic viruses, bacteria, fungi, and parasites to animals and humans. The objective of this study was to isolate and identify medically important filamentous fungi and yeasts from adult M. domestica collected from two wards of three hospital environments in Ahvaz city, Khuzestan Province, southwestern Iran. The common house flies were caught by a sterile net. These insects were washed in a solution of 1% sodium hypochlorite for 3 min and twice in sterile distilled water for 1 min. The flies were individually crushed with sterile swabs in sterile test tubes. Then 2 ml of sterile normal saline (0.85%) was added to each tube, and the tube was centrifuged for 5 min. The supernatant was then discarded, and the remaining sediment was inoculated with a sterile swab in the Sabouraud's dextrose agar medium containing chloramphenicol. Isolation and identification of fungi were made by standard mycological methods. In this research, totally 190 M. domestica from hospital environments were captured. In total, 28 fungal species were isolated. The main fungi isolated were Aspergillus spp. (67.4%), Penicillium sp. (11.6%), Mucorales sp. (11%), Candida spp. (10.5%), and Rhodotorula sp. (8.4%). Among the house flies caught at the hospitals, about 80% were found to carry one or more medically important species of fungi. This study has established that common house flies carry pathogenic fungi in the hospital environments of Ahvaz. The control of M. domestica in hospitals is essential in order to control the nosocomial fungal infections in patients.

Yeasts of the genital region of patients attending the dermatology service at Hospital São Paulo, Brazil

BACKGROUND

The knowledge of the diversity of yeasts that make up the skin microbiota of human beings is essential for the efficient monitoring of infections to which a person may be predisposed.

AIMS

This study identified yeasts comprising the genital skin microbiota of patients attending the Dermatology Service at the Hospital São Paulo-UNIFESP, Brazil.

METHODS

Samples were collected from the genital region of each patient and cultured on Sabouraud dextrose agar. Individual colonies were carefully transferred to tubes daily. Yeasts were identified based on classical methodologies and confirmed using a commercial kit.

RESULTS

Eighty-three patients were included in the study. Approximately 80% were women and 20% were men. The average age was 55 years. Hypertension, diabetes, kidney transplant and AIDS were the main underlying diseases reported by the patients. The most prevalent yeasts were Candida parapsilosis (36.1%), Rhodotorula mucilaginosa (9.2%), Rhodotorula glutinis (8.3%), Candida tropicalis (5.5%) and Trichosporon inkin (1.8%). Approximately 78% of the isolates were obtained in pure cultures. Trichosporon inkin was isolated only from women, in contrast to literature describing a high prevalence in males.

CONCLUSIONS

Our results suggest that Candida albicans is not the main yeast found on genital skin as previously thought, and opportunistic pathogens such as C. parapsilosis, C. tropicalis, Rhodotorula spp. and T. inkin make up the genital skin microbiota, representing a risk for infection in immunocompromised subjects. These results also indicate that women are carriers of T. inkin, the etiological agent of white piedra and trichosporonosis.

Species distribution and susceptibility profile to fluconazole, voriconazole and MXP-4509 of 551 clinical yeast isolates from a Romanian multi-centre study

This is the first multi-centre study regarding yeast infections in Romania. The aim was to determine the aetiological spectrum and susceptibility pattern to fluconazole, voriconazole and the novel compound MXP-4509. The 551 isolates were identified using routine laboratory methods, matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and DNA sequence analysis. Susceptibility testing was performed using the European Committee for Antimicrobial Susceptibility Testing (EUCAST) method and breakpoints. The yeasts originated from superficial infections (SUP, 51.5 %), bloodstream infections (BSI, 31.6 %) and deep-seated infections (DEEP, 16.9 %), from patients of all ages. Nine genera and 30 species were identified. The 20 Candida species accounted for 94.6 % of all isolates. C. albicans was the overall leading pathogen (50.5 %). Lodderomyces elongisporus is reported for the first time as a fungaemia cause in Europe. C. glabrata and Saccharomyces cerevisiae, as well as the non-Candida spp. and non-albicans Candida spp. groups, showed decreased fluconazole susceptibility (<75 %). The overall fluconazole resistance was 10.2 %. C. krusei accounted for 27 of the 56 fluconazole-resistant isolates. The overall voriconazole resistance was 2.5 % and was due mainly to C. glabrata and C. tropicalis isolates. Fluconazole resistance rates for the three categories of infection were similar to the overall value; voriconazole resistance rates differed: 4 % for BSI, 3.2 % for DEEP and 1.4 % for SUP. The antifungal activity of MXP-4509 was superior to voriconazole against C. glabrata and many fluconazole-resistant isolates. There was a large percentage of non-albicans Candida isolates. A large part of the high fluconazole resistance was not acquired but intrinsic, resulting from the high percentage of C. krusei.

Endocarditis caused by Rhodotorula infection

Rhodotorula is an emerging opportunistic fungal pathogen that is rarely reported to cause endocarditis. We describe a case involving a patient who developed endocarditis due to Rhodotorula mucilaginosa and Staphylococcus epidermidis, proven by culture and histopathology. The case illustrates the unique diagnostic and therapeutic challenges relevant to Rhodotorula spp.

Catheter-Associated Rhodotorula mucilaginosa Fungemia in an Immunocompetent Host

Rhodotorula species live in the environment, but can also colonize human epithelium, as well as respiratory, and gastrointestinal tracts. Reports of infection, especially in the past 2 decades, have noted increasing numbers of Rhodotorula infections, particularly in immunocompromised hosts, leading it to be considered emerging opportunistic pathogen. The major risk factors for infection were prolonged use of central venous catheters in patients with hematological and solid malignancies who are taking corticosteroids or cytotoxic drugs. Herein, we report a case of catheter-associated fungemia due to R. mucilaginosa in an immunocompetent host. The patient was admitted to the intensive care unit with mechanical ventilation for treatment of community-acquired pneumonia. After 10 days, the patient developed new-onset fever confirmed to be a result of catheter-associated blood-stream infection by R. mucilaginosa. It was successfully treated by catheter removal and intravenous amphotericin B.

Antifungal susceptibility of emerging opportunistic yeasts and yeast-like fungi from Rhea americana

Opportunistic yeasts and yeast-like fungi have been recognized as important pathogens in high-risk patients. This study aimed to evaluate the presence of these microorganisms in the microbiota of captive rheas and to investigate the antifungal susceptibility of the isolated strains. Isolates representing Magnusiomyces capitatus (Geotrichum capitatum, n = 11), Trichosporon mucoides (n = 11), Trichosporon asteroides (n = 5), Rhodotorula mucilaginosa (n = 4), Trichosporon asahii (n = 3), Trichosporon cutaneum (n = 3), and Trichosporon ovoides (n = 3) were obtained from the oropharynx, cloaca, and feces of 58 animals. Most of the isolates were susceptible to antifungals in vitro; however, resistance against fluconazole (n = 1) and itraconazole (n = 2) was detected among T. mucoides. This study indicates that healthy rheas can be reservoirs of opportunistic pathogens. Primary resistance to azoles in T. mucoides obtained from these animals demonstrates the potential risk to humans.

Synthesis, antifungal and cytotoxic activities of 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidinones

A series of sixteen novel thiazolidinone derivatives were synthesized from the efficient one-pot reaction of 2-(piperidin-1-yl)ethylamine, arenealdehydes and mercaptoacetic acid in good yields. Identification and characterization of products were achieved by NMR and GC-MS techniques. The in vitro antifungal activities of all synthesized compounds were evaluated against seven fungi: Candida albicans, Candida parapsilosis, Candida guilliermondii, Cryptococcus laurentii, Geotrichum sp, Trichosporon asahii and Rhodotorula sp. The results are expressed as the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) and the best results were found against the Rhodotorula sp yeast. Two thiazolidinones (4h and 4l), MIC and MFC (16.5 μg/mL) proved to be 1.6 times more active than fluconazole and four of them (4b, 4e, 4g and 4k (MIC and MFC 25 μg/mL)) showed similar activity of standard drug to Rhodotorula sp. In addition, the cytotoxicity of thiazolidinones 4a-p was evaluated on cultured Vero cells and most of them displayed low toxicity (above 98 μg/mL). These preliminary and important results could be considered a starting point for the development of new antifungal agents.

Epidemiology of Rhodotorula: an emerging pathogen

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.

Rhodotorula fungemia of an intensive care unit patient and review of published cases

Rhodotorula species are commensal yeasts that have emerged as a cause of life-threatening fungemia in severely immunocompromised patients. A case of Rhodotorula mucilaginosa fungemia in a 48-year-old woman that had undergone consecutive abdominal surgeries due to ovarian cancer and bowel necrosis while she was receiving fluconazole prophylaxis is presented. Several risk factors were identified such as presence of central venous catheters, solid organ neoplasm, abdominal surgery and administration of antibiotics. Identification was performed using commercial systems. The yeast was resistant to fluconazole, posaconazole and voriconazole and to echinocandins, whereas MIC to amphotericin B was 1.5 mg/L. Furthermore, published cases of Rhodotorula spp fungemia during the last decade are reviewed. In conclusion, Rhodotorula spp must be considered a potential pathogen in patients with immunosupression and central venous catheters. Correct identification is mandatory for appropriate management, as Rhodotorula spp are resistant to antifungal agents, such as fluconazole and echinocandins.

Rare opportunistic (non-Candida, non-Cryptococcus) yeast bloodstream infections in patients with cancer

BACKGROUND

Rare opportunistic (non-Candida, non-Cryptococcus) yeast bloodstream infections (ROYBSIs) are rare, even in cancer patients.

METHODS

We retrospectively reviewed all episodes of ROYBSIs occurring from 1998 to 2010 in our cancer center.

RESULTS

Of 2984 blood cultures positive for Candida and non-Candida yeasts, 94 (3.1%) were positive for non-Candida yeasts, representing 41 ROYBSIs (incidence, 2.1 cases/100,000 patient-days). Catheter-associated fungemia occurred in 21 (51%) patients. Breakthrough ROYBSIs occurred in 20 (49%) patients. The yeast species distribution was Rhodotorula in 21 (51%) patients, Trichosporon in 8 (20%) patients, Saccharomyces cerevisiae in 8 (20%) patients, Geotrichum in 2 (5%) patients, Pichia anomala, and Malassezia furfur in 1 patient each. All tested Trichosporon, Geotrichum, and Pichia isolates were azole-susceptible, whereas the Rhodotorula isolates were mostly azole-resistant. We noted echinocandin nonsusceptibility (minimal inhibitory concentration ≥ 2 mg/L) in all but the S. cerevisiae isolates. Most of the isolates (28/33 [85%]) were susceptible to amphotericin B. The mortality rate in all patients at 30 days after ROYBSIs diagnosis was 34%. Multivariate survival analysis revealed increased risk of death in patients with S. cerevisiae infections (hazard ratio, 3.7), Geotrichum infections (hazard ratio, 111.3), or disseminated infections (hazard ratio, 33.4) and reduced risk in patients who had catheter removal (hazard ratio, 0.1).

CONCLUSIONS

ROYBSIs are uncommon in patients with cancer, and catheters are common sources of them. Half of the ROYBSIs occurred as breakthrough infections, and in vitro species-specific resistance to echinocandins and azoles was common. Disseminated infections resulted in the high mortality rate.

Fungemia due to Rhodotorula mucilaginosa in an immunocompetent, critically ill patient

Infections due to the yeast Rhodotorula are rare in humans. R. mucilaginosa is responsible for the majority of human cases, and immunocompromised individuals with central venous catheters are at greatest risk. There are few reports of bloodstream infections due to R. mucilaginosa in immunocompetent patients. We present a case report of fungemia due to R. mucilaginosa in an immunocompetent, critically ill patient, with good evolution with catheter removal and fluconazole therapy. We briefly review the spectrum of infections due to R. mucilaginosa and the management of bloodstream infections due to this yeast.

Fungemia due to Rhodotorula mucilaginosa after allogeneic hematopoietic stem cell transplantation

Rhodotorula species have been increasingly recognized as emerging pathogens, particularly in immunocompromised patients. We herein report on a patient with myelodysplastic syndrome who developed fungemia due to Rhodotorula mucilaginosa after allogeneic hematopoietic stem cell transplantation (HSCT) from an unrelated donor. He developed severe acute graft-versus-host disease requiring high-dose steroids, and had serially been administered fluconazole and micafungin for the prophylaxis of fungal infection. Although several cases of Rhodotorula infection after HSCT have been reported, all of them were recipients of autologous HSCT, not allogeneic HSCT. A review of all the reported cases of Rhodotorula infection after HSCT revealed that all patients had received fluconazole or echinocandins before the onset of infection. The findings suggest that Rhodotorula species could be causative yeasts, particularly in patients receiving fluconazole or echinocandins, both of which are inactive against the species.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

Epidemiology and outcome of Rhodotorula infection in haematological patients

Rhodotorula spp. are emergent opportunistic pathogens, particularly in haematological patients. However, no systematic review of this infection has been undertaken in this high-risk patient group. The aim of this study was to review all reported cases of Rhodotorula infection to determine the epidemiology and outcome of this infection in this high-risk population. The 29 reported cases were fungaemias. The most common underlying haematological disorder was the presence of acute leukaemia (65.5%). Rhodotorula mucilaginosa was the species found more frequently (79.3%). Most cases (58.6%) had several risk factors (≥ 3) simultaneously. The most common predisposing factors were the presence of central venous catheter (CVC, 100%) and neutropenia (62.1%). A substantial number of patients (81.5%) received antifungal treatment with amphotericin B. The overall mortality was higher (13.8%) than that described in non-haematological patients (5.8% in solid-organ neoplasms and 9% in AIDS or other chronic diseases). Patients with acute leukaemia had a higher mortality rate (15.7%) than patients with non-Hodgkin's lymphoma (0%). Our data suggest that patients with acute leukaemia might be managed as high-risk patients and intensive measures might be taken. In addition, it appears that the subgroup of patients without acute leukaemia have a good outcome and might be managed as low-risk patients with a less intensive approach.

Epidemiology of invasive fungal infection

Invasive fungal infection is a growing cause of morbidity and mortality in immunosuppressed patients. Furthermore, the use of azole prophylaxis against Candida species has coincided with an increase in the incidence of invasive aspergillosis and infections by other filamentous fungi such as Mucorales. New risk factors and different timescales for onset have been identified. Knowledge of changes in the epidemiology of, and risk factors for, invasive fungal infection is particularly important when developing therapeutic strategies and effective prophylaxis to improve the prognosis of immunosuppressed patients.

Rhodotorula spp. isolated from blood cultures: clinical and microbiological aspects

The emergence of less common fungal pathogens has been increasingly reported in the last decade. We describe 25 cases of Rhodotorula spp. isolated from blood cultures at a large Brazilian tertiary teaching hospital from 1996-2004. We also investigated the in vitro activity of four antifungal drugs, using a standardized method. The median age of patients was 43 years. The majority of patients (88%) had a central venous catheter (CVC) and 10 (40%) were recipients of a bone marrow transplant. The episode was classified as a bloodstream infection (BSI) in 80% of the patients. Amphotericin B deoxycholate was the most common antifungal used and CVC was removed in 89.5% of the patients. Death occurred in four patients (17.4%), all classified as BSI. All strains were identified as R. mucilaginosa by conventional methods. Misidentification of the species was observed in 20% and 5% of the strains with the Vitek Yeast Biochemical Card and API 20C AUX systems, respectively. Amphotericin B demonstrated good in vitro activity (MIC50/90, 0.5 microg/ml) and the MICs for fluconazole were high for all strains (MIC50/90, >64 microg/ml).