Activities of available and investigational antifungal agents against rhodotorula species

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.

First reported Rhodotorula mucilaginosa brain abscess: Found as coinfection in woman with common variable immune deficiency

Rhodotorula is a rare pathogen seen in the immunocompromised host; while cases of Rhodotorula meningitis have been reported, there are no published cases of Rhodotorula brain abscess. We describe the diagnosis and management of a woman with common variable immune deficiency presenting with concomitant Rhodotorula and Nocardia brain abscesses.

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.

Management of Invasive Infections due to a Rare Arthroconidial Yeast, Saprochaete capitata, in Two Patients with Acute Hematological Malignancies

Saprochaete capitata is an arthroconidial yeast, found principally in the environment, even if it belongs also to the normal microbial flora that colonize human subjects. This yeast is increasingly associated with invasive infections in hematological patients, in particular in those affected by acute leukemia. An important risk factor that predisposes to this infection is the profound neutropenia present in such immunocompromised patients. Saprochaete spp. were found resistant to both echinocandins and fluconazole so the treatment is often difficult. Here, we report two cases of sepsis in two patients with acute leukemia. All of them had fatal events, due to the worsening of their clinical condition. An early diagnosis and appropriate management of these pathogens is important in consideration of the poor prognosis associated to these fungal invasive infections.

Antifungal Susceptibility Testing: A Primer for Clinicians

Clinicians treating patients with fungal infections may turn to susceptibility testing to obtain information regarding the activity of different antifungals against a specific fungus that has been cultured. These results may then be used to make decisions regarding a patient's therapy. However, for many fungal species that are capable of causing invasive infections, clinical breakpoints have not been established. Thus, interpretations of susceptible or resistant cannot be provided by clinical laboratories, and this is especially true for many molds capable of causing severe mycoses. The purpose of this review is to provide an overview of susceptibility testing for clinicians, including the methods used to perform these assays, their limitations, how clinical breakpoints are established, and how the results may be put into context in the absence of interpretive criteria. Examples of when susceptibility testing is not warranted are also provided.

All You Need To Know and More about the Diagnosis and Management of Rare Yeast Infections

Invasive infections with emerging yeasts such as Geotrichum, Saprochaete/Magnusiomyces, Trichosporon, and other species are associated with high morbidity and mortality rates. Due to the rarity and heterogeneity of these yeasts, medical mycology has lacked guidance in critical areas affecting patient management. Now, physicians and life scientists from multiple disciplines and all world regions have united their expertise to create the "Global guideline for the diagnosis and management of rare yeast infections: an initiative of the European Confederation of Medical Mycology in cooperation with the International Society for Human and Animal Mycology and the American Society for Microbiology." Recommendations are stratified for high- and low-resource settings and are therefore applicable worldwide. The advantages and disadvantages of various diagnostic methods and treatment options are outlined. This guideline reflects the current best-practice management for invasive rare yeast infections in a range of settings, with the intent of establishing a global standard of care for laboratorians and clinicians alike.

Species identification, antifungal susceptibility profiles and biofilm formation attributes of Rhodotorula isolates from ocular infections

BACKGROUND

Members of genus Rhodotorula are widely distributed in nature and have been traditionally considered non-pathogenic. Last few decades have seen the yeast as an emerging pathogen. We observed increase in numbers of Rhodotorula isolates from ocular infections in last few years, thus this prospective study was planned.

OBJECTIVES

To identify the species of Rhodotorula isolates from ocular infections. To know the antifungal susceptibilities and study the biofilm formation attributes of the isolates.

MATERIALS AND METHODS

Rhodotorula isolates were speciated using conventional methods, Matrix Assisted Laser Desorption and Ionisation - Time of Flight (MALDI- TOF) and sequencing of ITS region of ribosomal DNA. Antifungal susceptibility testing (AFST) was done using disc diffusion and E-test. Biofilm formation was studied using XTT [2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetra-zolium-5-carboxanilide] assay.

RESULTS

Twenty four isolates (92.3%) were identified as R. mucilaginosa and two as R. Minuta. AFST showed high MICs against Fluconazole, Amphotericin-B, Caspofungin, Micafungin and Flucytosine; MIC distribution from low to very high against Voriconazole, Itraconazole and Natamycin; and very low MICs against Posaconazole 57.7% of isolates were strong biofilm producers, 23.1% were moderate, and 19.2% were non producers.

CONCLUSIONS

This is the first prospective study on species distribution, antifungal susceptibility and biofilm production attributes of Rhodotorula isolates from ocular infections; also first time demonstrating the utility of proteomics based MALDI-TOF in diagnosing Rhodotorula up to species level. The study has shown high MICs against the conventional azoles, Amphotericin-B and Flucytosine. However, low MICs against Posaconazole and Natamycin give a hope for their possible therapeutic use.

Recent developments in less known and multi-resistant fungal opportunists

Fungal infections have increased in recent years due to host factors, such as oncohaematological and transplant-related disorders, immunosuppressive therapy, and AIDS. Additionally, molecular and proteomic facilities have become available to identify previously unrecognizable opportunists. For these reasons, reports on less-known and recalcitrant mycoses, such as those caused by black fungi, hyaline filamentous fungi, coelomycetes, Mucorales, and non-Candida yeasts have emerged. In this review, novel taxonomy in these groups, which often are multi-resistant to one or several classes of antifungals, is discussed. Clinical presentations, diagnosis and current treatment of some major groups are summarised.

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.

Along came a spider: an unusual organism identified in a peritoneal dialysis patient, a case report and literature review

Background

Peritoneal dialysis-associated peritonitis can uncommonly be caused by fungal infections. When they do present, they are associated with significant mortality and morbidity. We describe a case where a sample of peritoneal dialysate fluid grew Rhodotorula muciliginosa, a yeast organism present in the normal environment which has previously been reported as rarely causing peritonitis. We believe this is the first case where the Rhodotorula spp. and its origin has been identified.

Case presentation

A 20 year old male grew Rhodotorula muciliginosa from his peritoneal dialysis fluid on three separate occasions when a fluid sample was sent following a disconnection and subsequent set change. He was not systemically unwell and his peritoneal dialysate was clear. As Rhodotorula spp. is exceedingly difficult to treat our patient had his Tenchkoff catheter removed. Subsequent samples of soil and sand from his bearded dragon and Chilean tarantula cases, kept in his bedroom where dialysis occurred, were tested. The tarantula sand was identified as the source of the Rhodotorula spp. Of note, Candida was isolated from sand from the bearded dragon case. Once his Tenchkoff was removed he was treated with an intravenous course of antifungal therapy. He has since had a new Tenchkoff catheter inserted and recommenced PD following education around pets and hygiene.

Conclusions

In this era where people are keeping increasingly rare and unusual wildlife in their homes, this case highlights the need for clinician and nursing staff awareness of a patient’s home environment and hobbies when they are undergoing peritoneal dialysis. Sand from our patient’s tarantula case grew the colonising organism but interestingly soil from his bearded dragon case also isolated candida. This can also cause difficult to treat peritonitis.

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.

Rhodotorula dairenensis fungemia in a patient with cancer

BACKGROUND

Rhodotorula species were traditionally considered non-virulent environmental microorganisms, but are nowadays considered important human pathogens, especially in immunocompromised individuals.

CASE REPORT

We present the case of a 73 year-old man with diarrhea, anorexia and fever. In the blood analyses, both aerobic blood culture bottles yielded the growth of Rhodotorula dairenensis. The MALDI-TOF MS score was inadequate to provide an identification, which was achieved by means of molecular techniques. Treatment with an echinocandin was started, but the patient died.

CONCLUSIONS

Basidiomycetous yeast genera such as Rhodotorula can cause invasive and severe infections, e.g., fungemia, especially in patients with central venous catheter or another indwelling device.

Rhodotorula spp. in the gut - foe or friend?

Rhodotorula spp. belong to the basidiomyceteous fungi. They are widespread in the environment. Transmission to humans occur mainly through air and food. Intestinal colonization is rather common, but an overgrowth is normally suppressed, since their optimal growth temperature is exceeded in the body. A massive presence in the gut indicates a disturbance of the balance of the microbial flora due to different causes. One particular reason will be the treatment with azoles because this will create an advantage for these azole resistant fungi. First of all, the finding of increased numbers of Rhodotorula in stool specimen is not alarming. In contrast, the colonized human will profit from such a situation since these fungi produce a lot of useful nutrients such as proteins, lipids, folate, and carotinoids. Furthermore, a probiotic effect due to regulation of multiplication of pathogenic bacteria and by neutralizing or destroying their toxins can be anticipated. On the other hand, their massive presence may increase the risk of fungemia and ensuing organ infections especially when the host defense system is hampered. Indeed, Rhodotorula spp. range among the emerging fungal pathogens in the compromised host. However, it can be doubted whether all these opportunistic infections reported originate primarily from the gut.

Cell Envelope Integrity and Capsule Characterization of Rhodotorula mucilaginosa Strains from Clinical and Environmental Sources

Currently, there is very little known about the phenotypic variability within species of Rhodotorula strains and the role of their capsule. Cryptococcus neoformans has been considered the only encapsulated human fungal pathogen, but as more individuals come to live in states of immunocompromised health, they are more susceptible to fungal infections, including those by Rhodotorula. R. mucilaginosa species are some of those most commonly associated with clinical infections. We wanted to know if clinical and environmental strains of R. mucilaginosa demonstrated disparate capsule phenotypes. With limited antifungal options available and clinical Rhodotorula spp. often resistant to common antifungal drugs such as fluconazole, caspofungin (1, 2), and voriconazole (2), a better understanding of the fungal biology could inform the design and use of future antifungal drugs. The generation of an antibody specific to Rhodotorula fungi could be a useful diagnostic tool, and this work presents the first mention of such in the literature.

Rhodotorula yeasts are pink, encapsulated basidiomycetes isolated from a variety of environments and clinical settings. They are increasingly linked with disease, particularly central venous catheter infections and meningitis, in immunocompromised patients. Eight clinical and eight environmental strains molecularly typed as Rhodotorula mucilaginosa were compared to six Cryptococcus neoformans strains for phenotypic variability. Growth on cell integrity-challenging media suggested that R. mucilaginosa cells possess differences in signaling pathways, cell wall composition, or assembly and that their membranes are more susceptible to perturbations than those of C. neoformans. All 16 R. mucilaginosa strains produced urease, while none produced melanin with l-3,4-dihydroxyphenylalanine (l-DOPA) as a substrate. India ink staining reveals that clinical R. mucilaginosa capsules are larger than environmental capsules but that both are generally smaller than C. neoformans capsules. All R. mucilaginosa strains were resistant to fluconazole. Only two clinical strains were susceptible to voriconazole; all of the environmental strains were resistant. We generated an anticapsular antibody (Rh1) to R. mucilaginosa; Rh1 did not bind C. neoformans control strains, was specific to Rhodotorula species, and bound to all tested Rhodotorula strains. Binding assays performed with wheat germ agglutinin (WGA), concanavalin A (ConA), calcofluor white (CFW), and eosin Y dye (EY) cell surface probes suggested that chitin may be more accessible in R. mucilaginosa but that the total abundance of chitooligomers is less than in C. neoformans. This report describes a novel reagent that can be used to identify Rhodotorula species and lays the foundation for future cell envelope composition analysis.

IMPORTANCE Currently, there is very little known about the phenotypic variability within species of Rhodotorula strains and the role of their capsule. Cryptococcus neoformans has been considered the only encapsulated human fungal pathogen, but as more individuals come to live in states of immunocompromised health, they are more susceptible to fungal infections, including those by Rhodotorula. R. mucilaginosa species are some of those most commonly associated with clinical infections. We wanted to know if clinical and environmental strains of R. mucilaginosa demonstrated disparate capsule phenotypes. With limited antifungal options available and clinical Rhodotorula spp. often resistant to common antifungal drugs such as fluconazole, caspofungin (1, 2), and voriconazole (2), a better understanding of the fungal biology could inform the design and use of future antifungal drugs. The generation of an antibody specific to Rhodotorula fungi could be a useful diagnostic tool, and this work presents the first mention of such in the literature.

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.

Potential of Ravuconazole and its Prodrugs as the New OralTherapeutics for Onychomycosis

Onychomycosis is a fungal infection of the nail apparatus caused by dermatophytes, Candida and non-dermatophytic molds. It is highly prevalent in the general population worldwide and also responsible for significant morbidity and complications and does not usually cure itself. Thus, the condition needs to be treated in view of physical and psychological problems produced. Currently, oral medications using terbinafine are the most effective therapy, but it has relatively limited therapeutic success, particularly for long-term management. Such existing oral therapies are associated with high recurrence rates and treatment failure, as well as with potential adverse events and drug-drug interactions. In the light of these issues, development of more efficacious and safer alternatives for the treatment of onychomycosis is warranted.Ravuconazole and its prodrugs are promising new drug candidates for oral therapy of onychomycosis, among which a water-soluble prodrug, mono-lysine phosphoester derivative (E1224 or BFE1224) is in the most advanced stage of clinical development; a Phase II dose-finding study has been successfully completed and Phase III comparative studies are in progress in Japan.This review aims to summarize our current status of knowledge and information on ravuconazole and its prodrugs, particularly BFE1224, as the potential oral treatment option for onychomycosis. It also summarize the clinical features of onychomycosis with particular stress on its etiology, epidemiology, and current therapeutic options and their limitations. Given its clinical usefulness, BFE1224 may become a valuable addition to the current armamentarium for the treatment of onychomycosis.

Risk of Fungal Infection to Dental Patients

Fungi can cause various diseases, and some pathogenic fungi have been detected in the water of dental equipment. This environment offers suitable conditions for fungal biofilms to emerge, which can facilitate mycological contamination. This study verified whether the water employed in the dental units of two dental clinics at the University of Franca was contaminated with fungi. This study also evaluated the ability of the detected fungi to form biofilms. The high-revving engine contained the largest average amount of fungi, 14.93 ± 18.18 CFU/mL. The main fungal species verified in this equipment belonged to the genera Aspergillus spp., Fusarium spp., Candida spp., and Rhodotorula spp. Among the isolated filamentous fungi, only one fungus of the genus Fusarium spp. did not form biofilms. As for yeasts, all the Candida spp. isolates grew as biofilm, but none of the Rhodotorula spp. isolates demonstrated this ability. Given that professionals and patients are often exposed to water and aerosols generated by the dental procedure, the several fungal species detected herein represent a potential risk especially to immunocompromised patients undergoing dental treatment. Therefore, frequent microbiological monitoring of the water employed in dental equipment is crucial to reduce the presence of contaminants.

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.

Consensus guidelines for the treatment of yeast infections in the haematology, oncology and intensive care setting, 2014

Pathogenic yeast forms are commonly associated with invasive fungal disease in the immunocompromised host, including patients with haematological malignancies and patients of haemopoietic stem cell transplants. Yeasts include the Candida spp., Cryptococcus spp., Pneumocystis jirovecii and some lesser-known pathogens. Candida species remain the most common cause of invasive yeast infections (and the most common human pathogenic fungi). These guidelines present evidence-based recommendations for the antifungal management of established, invasive yeast infections in adult and paediatric patients in the haematology/oncology setting. Consideration is also given to the critically ill patient in intensive care units, including the neonatal intensive care unit. Evidence for 'pre-emptive' or 'diagnostic-driven antifungal therapy' is also discussed. For the purposes of this paper, invasive yeast diseases are categorised under the headings of invasive candidiasis, cryptococcosis and uncommon yeast infections. Specific recommendations for the management of Pneumocystis jirovecii are presented in an accompanying article (see consensus guidelines by Cooley et al. appearing elsewhere in this supplement).

Antifungal activity of four honeys of different types from Algeria against pathogenic yeast: Candida albicans and Rhodotorula sp

OBJECTIVE

To evaluate the antifungal activity of four honeys of different types from Algeria against pathogenic yeast i.e. Candida albicans (C. albicans) and Rhodotorula sp.

METHODS

Four Algeria honeys of different botanical origin were analyzed to test antifungal effect against C. albicans, and Rhodotorula sp. Different concentrations (undiluted, 10%, 30%, 50% and 70% w/v) of honey were studied in vitro for their antifugal activity using C. albicans and Rhodotorula sp. as fungal strains.

RESULTS

The range of the diameter of zone of inhibition of various concentrations of tested honeys was (7-23 mm) for Rhodotorula sp., while C. albicans showed clearly resistance towards all concentrations used. The MICs of tested honey concentrations against C. albicans and Rhodotorula sp. were (70.09-93.48)% and (4.90-99.70)% v/v, respectively.

CONCLUSIONS

This study demonstrates that, in vitro, these natural products have clearly an antifungal activity against Rhodotorula sp. and C. albicans.

A Case of Onychomycosis Caused by Rhodotorula glutinis

Rhodotorula spp. have emerged as opportunistic pathogens, particularly in immunocompromised patients. The current study reports a case of onychomycosis caused by Rhodotorula glutinis in a 74-year-old immunocompetent female. The causative agent was identified as R. glutinis based on the pinkish-orange color; mucoid-appearing yeast colonies on Sabouraud Dextrose Agar at 25°C; morphological evaluation in the Corn Meal-Tween 80 agar; observed oval/round budding yeast at 25°C for 72 hours; no observed pseudohyphae; positive urease activity at 25°C for 4 days; and assimilation features detected by API ID 32C kit and automated Vitek Yeast Biochemical Card 2 system. Antifungal susceptibility test results were as follows: amphotericin B (MIC = 0.5 µg/mL), fluconazole (MIC = 128 µg/mL), itraconazole (MIC = 0.125 µg/mL), voriconazole (MIC = 1 µg/mL), posaconazole (MIC = 0.5 µg/mL), anidulafungin (MIC = 0.5 µg/mL), and caspofungin (MIC = 16 µg/mL). Antifungal therapy was initiated with oral itraconazole at a dose of 400 mg/day; seven-day pulse therapy was planned at intervals of three weeks. Clinical recovery was observed in the clinical evaluation of the patient before the start of the third cure. Although R. glutinis has rarely been reported as the causative agent of onychomycosis, it should be considered.

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.

Rhodotorula mucilaginosa associacted meningitis: A subacute entity with high mortality. Case report and review

A fatal case of meningitis due to Rhodotorula mucilaginosa in a 28 year-old HIV-negative male with a history of Hodgkin lymphoma who underwent salvage chemotherapy is presented. Reviewing the literature we identified 13 cases with central nervous system infection due Rhodotorula spp. The disease usually occurs in HIV negative immunosupressed middle-aged males. It takes the form of subacute or chronic meningitis accompanied by fever with an overall mortality of 46.2% despite antifungal therapy.

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.

In vitro activity of natural honey alone and in combination with curcuma starch against Rhodotorula mucilaginosa in correlation with bioactive compounds and diastase activity

OBJECTIVE

To evaluate the in vitro activity and synergism of the combinations of natural honey and curcuma starch against Rhodotorula mucilaginosa in correlation with total phenolic, flavonoid contents, and diastase activity.

METHODS

The Folin-Ciocalteu test was used to determine the total polyphenols content and the flavonoid content was analyzed using by the aluminum chloride method. The antifungal activity of the natural honey, determined by an agar well diffusion assay and agar incorporation method.

RESULTS

Total phenolic content varied from (63.930.11) to (95.366.08) mg GAE/100 g honey as gallic acid equivalent. Total flavonoids content varied from (5.41±0.04) to (9.94±0.54) mg CE/100 g. Diastase activity values were between (7.3±2.8) and (26±2.8). The zone inhibition diameter for the six honey samples without starch ranged between 6 and 20 mm. When starch was mixed with honey and then added to well, a zone inhibition increase diameter 7 and 21 mm. The percentage increase was noticed with each variety and it ranged between 5% and 62.5%. The minimal inhibitory concentrations for the six varieties of honey without starch against Rhodotorula mucilaginosa ranged between 28% and 36% (v/v). When starch was incubated with honey and then added to media, a minimal inhibitory concentration drop has been noticed with each variety. It ranged between 6.66 % and 20% (w/v). No significant correlation was established between diastase activity and bioactive compounds.

CONCLUSIONS

The mixture of curcuma starch and honey could lead to the development of new combination antibiotics against Rhodotorula infections.

Clinical utility of a panfungal polymerase chain reaction assay for invasive fungal diseases in patients with haematologic disorders

OBJECTIVES

Invasive fungal diseases (IFDs) are life-threatening events in patients with haematologic disorders, and the spectrum of the aetiological pathogens continues to expand. This study aimed to evaluate the clinical utility of a panfungal polymerase chain reaction (PCR) assay for the management of IFDs in such patients.

METHODS

We prospectively analysed 273 consecutive blood samples from 64 risk episodes in 51 patients with haematologic disorders at high risk for IFD who were treated at our hospital between April 2007 and October 2010.

RESULTS

PCR-positive results were obtained in 18 of 64 risk episodes (35.3%). IFD was documented in 14 episodes (21.9%, 9 probable IFDs and 5 possible IFDs) according to the revised criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group. PCR was positive in all of these 14 episodes, and in 4 of the 50 episodes with no IFD category. Sensitivity, specificity, positive predictive value, and negative predictive value of our assay were 100%, 92%, 78% and 100% respectively. A considerable number of fungi (44.4%) that are less common than Aspergillus and Candida species were positive by PCR. Molecular diagnoses of Cunninghamella species, Aspergillus ustus, Fusarium species, Scedosporium apiospermum, Rhodotorula species and Rhizopus species were beneficial in selecting suitable treatments.

CONCLUSIONS

Our panfungal PCR approach allows for the highly sensitive and specific detection and identification of a wide spectrum of fungal pathogens, which provides indispensable information for managing IFDs, especially refractory or breakthrough IFDs during antifungal therapy in high-risk patients with haematologic disorders.

Rhodotorula minuta fungemia in a ewe lamb

An 8-month-old crossbred ewe, normal upon physical examination, was humanely euthanized for tissue collection. After approximately 3 weeks in tissue culture, fungi began budding out of cells obtained from the choroid plexus. After an additional 3 weeks, budding was observed in kidney cell cultures and eventually in monocyte cultures as well. Serum from the lamb was submitted to the Veterinary Diagnostic Laboratory at Colorado State University for fungal diagnosis and was found negative for Aspergillus, Blastomyces, Coccidioidomycosis and Histoplasmosis. DNA was isolated from fungi collected from tissue culture supernatants and used in a set of pan-fungal PCR assays with DNA from Candida acting as a positive control. PCR products were sequenced and BLAST analysis performed. The unknown fungal sequence aligned with 100% identity to Rhodotorula minuta an emerging opportunistic pathogen. Samples were submitted to The Fungal Testing Laboratory at The University of Texas Health Science Center at San Antonio for additional validation. We believe this to be the first report of Rhodotorula fungemia in a sheep in the United States.

Molecular identification, antifungal susceptibility profile, and biofilm formation of clinical and environmental Rhodotorula species isolates

Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC(50)/MIC(90), 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species.

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.

Voriconazole in the management of nosocomial invasive fungal infections

Voriconazole is a new triazole developed for the treatment of life-threatening fungal infections. The drug is available for both oral and intravenous administration; the oral formulation has excellent bioavailability. The side-effect profile of voriconazole presents an acceptable safety and tolerability spectrum: transient visual disturbances, liver enzyme abnormalities, and skin rashes are the most frequently reported side effects but rarely lead to discontinuation. The potential for drug–drug interactions is high, because of its extensive hepatic metabolism. Careful attention to dosage is required, and serum levels and the effects of interacting drugs should be monitored. Review of 25 470 isolates of yeasts and 3216 isolates of filamentous fungi showed voriconazole to have broad-spectrum activity against pathogenic yeasts including intrinsically fluconazole-resistant isolates such as Candida krusei, dimorphic fungi, and opportunistic moulds like Aspergillus spp, amphotericin-B-resistant Aspergillus terreus, Fusarium spp, and Scedosporium apiospermum. It displays excellent clinical efficacy in patients with fluconazole-resistant and -susceptible Candida infections, invasive bone and central nervous system aspergillosis, and various refractory fungal infections. Voriconazole has been approved by the US Food and Drug Administration and by the European Medicines Agency for the treatment of invasive aspergillosis, serious infections caused by Fusarium and S. apiospermum, fluconazole-resistant invasive Candida infections, and candidemia in nonneutropenic patients.

Rhodotorula fungemia: two cases and a brief review

Rhodotorula is emerging as an important cause of nosocomial and opportunistic infections. We present two cases of Rhodotorula mucilaginosa fungemia diagnosed over a period of 3 months at our hospital. The first case was of a pre-term neonate in the neonatal ICU who presented with respiratory failure and sepsis. The second involved an adult female who had been injured in a road traffic accident requiring an operation for a hematoma and was later shifted to the medical ICU. For a new hospital like ours, finding two cases of Rhodotorula fungemia within a span of 3 months prompted us to describe them in this report. These cases emphasize the emerging importance of Rhodotorula mucilaginosa as a pathogen and the importance of identification and MIC testing for all fungal isolates recovered from the blood stream.

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.

Microbiological monitoring of mineral water commercialized in Brazil

The quality of mineral water commercialized in Brazil regarding the microbial content was analyzed and the results were compared with the standards established by the current legislation. Results demonstrated there was no bacterial contamination, but several types of fungi were found. Therefore, bottled mineral water could be considered a possible route for the transmission of filamentous fungi and yeasts.

Meningitis caused by Rhodotorula mucilaginosa in human immunodeficiency virus seropositive patient

Rhodotorula species may be responsible for systemic infection in immunocompromised patients. Meningitis by Rhodotorula species in human immunodeficiency virus (HIV) infected persons has been reported previously. We report a case of meningitis caused by Rhodotorula mucilaginosa in a 36-year-old HIV seropositive male patient who presented with fever, altered sensorium and features of meningeal irritation i.e. neck rigidity. The Cerebrospinal fluid (CSF) cell counts were high, showing 150 cells/mm(3), with 60% lymphocytes and 40% polymorphs, and protein content of 100 mg%; glucose was 60 mg%. The diagnosis was confirmed by culture on Sabouraud's Dextrose agar. The patient was treated successfully with intensive Amphotericin B (1 mg/kg), for two weeks, followed by oral Itraconazole (400 mg daily), for a period of two months. The patient was started on anti retroviral therapy. He did not show any relapse of the symptoms when the last follow up was done six months after the date of discharge.

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.