Azole therapy for trichosporonosis: clinical evaluation of eight patients, experimental therapy for murine infection, and review

Trichosporon asahii causing subcutaneous mycoses in an immunocompetent patient: case report and a minireview

Trichosporon spp. are a constituent of the normal flora of humans that can cause both superficial and invasive infections, mainly in immunocompromised and immunocompetent hosts, respectively. Herein, we a report of Trichosporon asahii causing subcutaneous fungal infection (SFI) in an immunocompetent patient after carpal tunnel surgery. Although susceptible to fluconazole, the treatment of SFI failed even using high doses of this azole. The skin lesion improved following the administration of voriconazole. We conducted a literature minireview searching reports on SFI in immunocompetent patients to check for epidemiological, diagnostic, therapeutic, and outcome characteristics. A total of 32 cases were reported. Despite being uncommon, the clinical suspicion and early diagnosis of SFI in immunocompetent patients undergoing previous surgery are important. Our study indicated that the azoles are the most active antifungal agents against Trichosporon spp., except for fluconazole, and voriconazole can be considered the first therapeutic option.

Invasive Trichosporonosis in Neonates and Pediatric Patients with Malignancies or Hematologic Disorders

(1) Background: Trichosporon species have emerged as important opportunistic fungal pathogens, with Trichosporon asahii being the leading and most frequent cause of invasive disease. (2) Methods: We performed a global review focused on invasive trichosporonosis in neonates and pediatric patients with malignancies or hematologic disorders. We reviewed case reports and case series of trichosporonosis due to T. asahii published since 1994, the year of the revised taxonomic classification. (3) Results: Twenty-four cases of invasive trichosporonosis were identified in neonates with the presence of central venous catheter and use of broad-spectrum antibiotics recognized as the main predisposing factors. Thirty-two cases were identified in children with malignancies or hematologic disorders, predominantly with severe neutropenia. Trichosporon asahii was isolated from blood in 24/32 (75%) pediatric cases. Cutaneous involvement was frequently observed in invasive trichosporonosis. Micafungin was the most commonly used prophylactic agent (9/22; 41%). Ten patients receiving prophylactic echinocandins were identified with breakthrough infections. A favorable outcome was reported in 12/16 (75%) pediatric patients receiving targeted monotherapy with voriconazole or combined with liposomal amphotericin B. Overall mortality in neonates and children with malignancy was 67% and 60%, respectively. (4) Conclusions: Voriconazole is advocated for the treatment of invasive trichosporonosis given the intrinsic resistance to echinocandins and poor susceptibility to polyenes.

Epidemiology, clinical aspects, outcomes and prognostic factors associated with Trichosporon fungaemia: results of an international multicentre study carried out at 23 medical centres

BACKGROUND

Trichosporon fungaemia (TF) episodes have increased in recent years and mortality rates remain high despite the advances in the management of sepsis. New concepts about its clinical course, treatment and microbiology need to be investigated for the better management of this infection.

OBJECTIVES

To describe the aetiology, natural history, clinical management and prognostic factors of TF.

METHODS

TF episodes documented between 2005 and 2018 in 23 South American centres were retrospectively investigated by using a standard clinical form. Molecular identification, antifungal susceptibility testing and biofilm production were also performed.

RESULTS

Eighty-eight TF episodes were studied. Patients had several underlying conditions, including haematological diseases (47.7%), post-operative status (34%), solid organ transplants (n = 7, 7.9%), among others. Seventy-three (82.9%) patients had a central venous catheter (CVC) at TF diagnosis. The 30 day mortality rate was 51.1%. Voriconazole-based therapy was given to 34 patients (38.6%), with a 30 day mortality rate of 38.2%. Multivariate predictors of 30 day mortality were age (OR 1.036), mechanical ventilation (OR 8.25) and persistent neutropenia (OR 9.299). CVC removal was associated with over 75% decreased risk of 30 day mortality (OR 0.241). Microbiological analyses revealed that 77.7% of the strains were identified as Trichosporon asahii, and voriconazole showed the strongest in vitro activity against Trichosporon spp. Most of the strains (63%) were considered medium or high biofilm producers.

CONCLUSIONS

Older age, mechanical ventilation and persistent neutropenia were associated with poor prognosis. CVC may play a role in the pathogenicity of TF and its removal was associated with a better prognosis.

Progress in Definition, Prevention and Treatment of Fungal Infections in Cystic Fibrosis

Cystic fibrosis (CF) is a chronic lethal multi-system condition; however, most of the morbidity and mortality is dependent on the status of the respiratory system. Progressive respiratory decline is mediated by chronic infection and inflammation, punctuated by important acute events known as pulmonary exacerbations which can lead to accelerated decline. The main bacterial species causing infections include Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae and Achromobacter xylosoxidans. In addition to bacteria, fungi are detected in a significant number of patients. The impact of fungal colonization of the airways is still not completely elucidated, but an increasing body of evidence suggests an important role for moulds and yeasts. Although fungal infections are rare, fungi can cause severe pneumonia requiring appropriate targeted treatment. The most common fungi in respiratory samples of patients with CF are Aspergillus fumigatus, Aspergillus terreus and Scedosporium species for filamentous fungi, and yeasts such as Candida albicans and Candida glabrata. Therapeutic strategies depend on the detected fungus and the underlying clinical status of the patient. The antifungal therapy can range from a simple monotherapy up to a combination of three different drugs. Treatment course may be indicated in some patients for two weeks and in others for up to six months, and in rare cases even longer. New antifungal drugs have been developed and are being tested in clinical studies offering the hope of therapeutic alternatives to existing drugs. Identifying relevant risk factors and diagnostic criteria for fungal colonization and infection is crucial to enabling an adequate prevention, diagnosis and treatment.

Invasive Trichosporon Infection: a Systematic Review on a Re-emerging Fungal Pathogen

Objectives: This review aimed to better depict the clinical features and address the issue of therapeutic management of Trichosporon deep-seated infections.

Methods: We comprehensively reviewed the cases of invasive Trichosporon infection reported in the literature from 1994 (date of taxonomic modification) to 2015. Data from antifungal susceptibility testing (AST) studies were also analyzed.

Results: Two hundred and three cases were retained and split into four groups: homeopathy (n = 79), other immunodeficiency conditions (n = 41), miscellaneous (n = 58) and newborns (n = 25). Trichosporon asahii was the main causative species (46.7%) and may exhibit cross-resistance to different antifungal classes. The unfavorable outcome rate was at 44.3%. By multivariate analysis, breakthrough infection (OR 2.45) was associated with unfavorable outcome, whilst the use of an azole-based therapy improved the prognosis (OR 0.16). Voriconazole-based treatment was associated with favorable outcome in hematological patients (73.6 vs. 41.8%; p = 0.016). Compiled data from AST demonstrated that (i) T. asahii exhibits the highest MICs to amphotericin B and (ii) voriconazole has the best in vitro efficacy against clinical isolates of Trichosporon spp.

Conclusions:Trichosporon infection is not only restricted to hematological patients. Analysis of compiled data from AST and clinical outcome support the use of voriconazole as first line therapy.

Trichosporon fungemia in a pediatric patient with acute lymphoblastic leukemia

Trichosporon fungemia is a life-threatening opportunistic infection that is increasing in frequency. Invasive disease occurs almost exclusively in immunocompromised hosts, particularly in neutropenic adults with hematological malignancies and uncommonly in children. We report the case of a pediatric patient where disseminated trichosporonosis progressed while on micafungin, between treatments with voriconazole and amphotericin B, demonstrating the difficulty with and importance of prolonged and continuous treatment.

Epidemiology and Outcome of Trichosporon Fungemia: A Review of 185 Reported Cases From 1975 to 2014

We first reviewed the English-language literature for reported cases of Trichosporon fungemia over the past four decades, and did comprehensive analysis in order to guide our understanding of epidemiology and outcome-related aspects, especially the antifungal treatment and CVC management.

Background. Trichosporon species have emerged as an important non-Candida spp yeast pathogen in immunocompromised patients in recent decades; however, the systemic analysis of Trichosporon epidemiology has seldom been reported.

Methods. We reviewed 185 reported cases of Trichosporon fungemia from 1975 to 2014 in the English-language literature, and the epidemiology and prognostic factors of the included cases are described.

Results. The number of cases reported has increased with time, especially over the past decade. During the 3 decades from 1975 to 2004, the most commonly used antifungal compounds were amphotericin B/liposomal amphotericin B; however, in recent decades (2005–2014), triazoles (especially voriconazole) have become the most widely used agents, significantly improving outcome in the reported cases. Correlation analysis revealed that negative outcome is associated with several prognostic factors, including a history of antimicrobial use, bacterial bloodstream coinfection, prophylactic/empirical antifungal therapy, Trichosporon beigelii infection, and receiving the antifungal regimen of amphotericin B/liposomal amphotericin B. In addition, a significantly greater proportion of patients with a positive outcome had fungemia without invasive tissue infection and received a voriconazole regimen or an AmB-triazole combined regimen. Significant positive outcome was also associated with patients who had recovered from neutropenia or after central venous catheter removal.

Conclusions. Voriconazole can be recommended as a first-line antifungal compound to treat Trichosporon fungemia; the immune status of the host plays a crucial role in the outcome of this infection, and the removal of vascular catheters should be considered if feasible.

How we treat invasive fungal diseases in patients with acute leukemia: the importance of an individualized approach

Invasive fungal diseases (IFDs) represent an important cause of treatment failure in adults with acute leukemia. Because of leukemia’s heterogeneity, the risk for IFDs is highly variable. We therefore apply a risk-adapted antifungal strategy with strong emphasis on pretreatment and day-15 posttreatment to allow earlier and more individualized interventions. We determine pretreatment risks for IFDs based on 4 factors: (1) host fitness for standard therapy (ie, fit, unfit, or frail); (2) leukemia resistance (high vs low probability of achieving complete remission [CR]); (3) anticipated treatment-related toxicity such as neutropenia, mucositis, and steroid-induced immunosuppression; and (4) patient exposure to opportunistic fungi. Accordingly, we stratify patients as high, intermediate, or low risk for IFDs and apply risk-adapted antifungal strategies, including primary or secondary prophylaxis and diagnostic-based preemptive or empiric therapy. Prevention of IFDs also relies on optimizing organ function, decreasing exposure to opportunistic fungi, and improving net state of immunosuppression with use of better-tolerated and investigational agents for unfit patients and those with adverse leukemia biology. Novel targeted and safe therapies that can achieve higher rates of sustained CR among patients with adverse genetics offer the best promise for reducing the burden of IFDs in these patients.

Multiple species of Trichosporon produce biofilms highly resistant to triazoles and amphotericin B

Invasive infections caused by Trichosporon spp. have increased considerably in recent years, especially in neutropenic and critically ill patients using catheters and antibiotics. The genus presents limited sensitivity to different antifungal agents, but triazoles are the first choice for treatment. Here, we investigated the biofilm production and antifungal susceptibility to triazoles and amphotericin B of 54 Trichosporon spp. isolates obtained from blood samples (19), urine (20) and superficial mycosis (15). All isolates and 7 reference strains were identified by sequence analysis and phylogenetic inferences of the IGS1 region of the rDNA. Biofilms were grown on 96-well plates and quantitation was performed using crystal violet staining, complemented with Scanning Electron Microscopy (SEM). Susceptibility tests for fluconazole, itraconazole, voriconazole and amphotericin B were processed using the microdilution broth method (CLSI) for planktonic cells and XTT reduction assay for biofilm-forming cells. Our results showed that T. asahii was the most frequent species identified (66.7%), followed by T. faecale (11.1%), T. asteroides (9.3%), T. inkin (7.4%), T. dermatis (3.7%) and one T. coremiiforme (1.8%). We identified 4 genotypes within T. asahii isolates (G1, G3, G4 and G5) and 2 genotypes within T. faecale (G1 and G3). All species exhibited high adhesion and biofilm formation capabilities, mainly T. inkin, T. asteroides and T. faecale. Microscopy images of high biofilm-producing isolates showed that T. asahii presented mainly hyphae and arthroconidia, whereas T. asteroides exhibited mainly short arthroconidia and few filaments. Voriconazole exhibited the best in vitro activity against all species tested. Biofilm-forming cells of isolates and reference strains were highly resistant to all antifungals tested. We concluded that levels of biofilm formation by Trichosporon spp. were similar or even greater than those described for the Candida genus. Biofilm-forming cells were at least 1,000 times more resistant to antifungals than planktonic cells, especially to voriconazole.

Treatment of invasive fungal infections in cancer patients-updated recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

The Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO) here presents its updated recommendations for the treatment of documented fungal infections. Invasive fungal infections are a main cause of morbidity and mortality in cancer patients undergoing intensive chemotherapy regimens. In recent years, new antifungal agents have been licensed, and agents already approved have been studied in new indications. The choice of the most appropriate antifungal treatment depends on the fungal species suspected or identified, the patient's risk factors (e.g., length and depth of neutropenia), and the expected side effects. This guideline reviews the clinical studies that served as a basis for the following recommendations. All recommendations including the levels of evidence are summarized in tables to give the reader rapid access to the information.

Non-healing ulcer due to Trichosporon loubieri in an immunocompetent host and review of published reports

We report here a case of non-healing ulcer due to Trichosporon loubieri in an apparently immunocompetent female. The identity of isolate was confirmed by DNA sequencing of D1/D2 region of 26S rDNA. The minimum inhibitory concentrations of the isolate were amphotericin B-0.5 μg/ml; fluconazole-4 μg/ml; posaconazole-0.25 μg/ml; voriconazole-0.06 μg/ml. The patient was managed by extensive debridement and oral fluconazole 150 mg daily for 6 weeks. She responded to therapy. To the best of our knowledge, till date, this is the fourth report of human infection due to T. loubieri and the first of its kind in an immunocompetent host. A review of published literature on infections due to T. loubieri is also included.

Current knowledge of Trichosporon spp. and Trichosporonosis

Trichosporon spp. are basidiomycetous yeast-like fungi found widely in nature. Clinical isolates are generally related to superficial infections. However, this fungus has been recognized as an opportunistic agent of invasive infections, mostly in cancer patients and those exposed to invasive medical procedures. It is possible that the ability of Trichosporon strains to form biofilms on implanted devices, the presence of glucuronoxylomannan in their cell walls, and the ability to produce proteases and lipases are all factors likely related to the virulence of this genus and therefore may account for the progress of invasive trichosporonosis. Disseminated trichosporonosis has been increasingly reported worldwide and represents a challenge for both diagnosis and species identification. Phenotypic identification methods are useful for Trichosporon sp. screening, but only molecular methods, such as IGS region sequencing, allow the complete identification of Trichosporon isolates at the species level. Methods for the diagnosis of invasive trichosporonosis include PCR-based methods, Luminex xMAP technology, and, more recently, proteomics. Treating patients with trichosporonosis remains a challenge because of limited data on the in vitro and in vivo activities of antifungal drugs against clinically relevant species of the genus. Despite the mentioned limitations, the use of antifungal regimens containing triazoles appears to be the best therapeutic approach.

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.

Successful treatment of Trichosporon fungemia in a patient with refractory acute myeloid leukemia using voriconazole combined with liposomal amphotericin B

Trichosporon fungemia is a rare and fatal fungal infection that occurs in patients with prolonged neutropenia associated with hematologic malignancies. A 21-year-old male developed Trichosporon fungemia during remission induction therapy for acute myeloid leukemia (AML). Although two courses of induction therapy failed to induce a remission of AML, combination therapy with voriconazole and liposomal amphotericin B (L-AmB) followed by monocyte colony-stimulating factor ameliorated the Trichosporon fungemia and enabled the patient to receive reduced-intensity bone marrow transplantation (BMT) from his human leukocyte antigen-A one-locus mismatched mother. The patient achieved a durable remission after BMT without exacerbation of Trichosporon fungemia. The combination therapy with voriconazole and L-AmB may therefore be useful in controlling Trichosporon fungemia associated with prolonged neutropenia after remission induction therapy for AML.

Trichosporon mycotoxinivorans, a novel respiratory pathogen in patients with cystic fibrosis

This report describes the molecular epidemiology, in vitro susceptibility, colonial and microscopic morphologies, and biochemical features of Trichosporon mycotoxinivorans, a newly recognized pathogen that appears to have a propensity for patients with cystic fibrosis. The index patient died with histologically documented Trichosporon pneumonia complicating cystic fibrosis. This is also the first report of disease caused by a Trichosporon species in a nontransplant patient with cystic fibrosis. As T. mycotoxinivorans has not previously been recognized as a respiratory pathogen, the significance of its recovery from sputum samples was not initially appreciated. Genetic analysis of archived clinical samples found three additional cases of T. mycotoxinivorans infection which had previously been identified as other members of the genus. An additional isolate of T. mycotoxinivorans was identified from a clinical sample on initial testing. Three of these four cases were also patients with cystic fibrosis. All isolates had MICs at 48 h of amphotericin B of > or = 1 microg/ml and of echinocandins of > or = 16 microg/ml, but they displayed various susceptibilities to the triazoles. In summary, Trichosporon mycotoxinivorans is a newly recognized human pathogen that is associated with cystic fibrosis.

Trichosporonosis in a tertiary care cancer center: Risk factors, changing spectrum and determinants of outcome

To assess the spectrum and outcome of trichosporonosis (TS) in cancer patients, we reviewed the medical records of 17 such patients with TS. TS presented most commonly as fungemia (n = 10, including 7 with central-venous-catheter-related infection) and either pulmonary or soft tissue infection (n = 3, each). Most patients (65%) had acute leukemia, 11 (65%) had neutropenia, and 9 (53%) had received high doses of corticosteroids. 10 patients had breakthrough TS during therapy with at least 1 of the following: amphotericin B, fluconazole, itraconazole, and voriconazole. The 30-d crude mortality rate was 53%. Predictors of mortality by using univariate analysis included: high median APACHE II score (p < 0.01), use of high dose of corticosteroids (p = 0.01), and admission to the intensive care unit (p < 0.01). TS is associated with a high mortality rate in cancer patients. The spectrum of infection at our institution has shifted from a predominance of disseminated infection to CVC-related fungemias without evidence of tissue invasion.

Fungal Infections

The incidence of invasive fungal infections has increased dramatically over the past two decades, mostly due to an increase in the number of immunocompromised patients.1–4 Patients who undergo chemotherapy for a variety of diseases, patients with organ transplants, and patients with the acquired immune deficiency syndrome have contributed most to the increase in fungal infections.5 The actual incidence of invasive fungal infections in transplant patients ranges from 15% to 25% in bone marrow transplant recipients to 5% to 42% in solid organ transplant recipients.6,7 The most frequently encountered are Aspergillus species, followed by Cryptococcus and Candida species. Fungal infections are also associated with a higher mortality than either bacterial or viral infections in these patient populations. This is because of the limited number of available therapies, dose-limiting toxicities of the antifungal drugs, fewer symptoms due to lack of inflammatory response, and the lack of sensitive tests to aid in the diagnosis of invasive fungal infections.1 A study of patients with fungal infections admitted to a university-affiliated hospital indicated that community-acquired infections are becoming a serious problem; 67% of the 140 patients had community-acquired fungal pneumonia.8

Endophthalmitis due to Trichosporon beigelii in acute leukemia

We describe 2 patients with hematologic malignancy who developed endophthalmitis due to Trichosporon beigelii during the course of treatment with multiagent chemotherapy. Blood cultures revealed T beigelii for both patients. Although one of the patients was treated with fluconazole (FLCZ) and 5-fluorocytosine, the trichosporonous endophthalmitis was resistant to both drugs. This patient subsequently received amphotericin B (AMPH-B) therapy, and the eyes were treated with vitrectomy. The second patient also received AMPH-B for FLCZ-resistant trichosporonous chorioretinitis. In both patients, systemic treatment with AMPH-B successfully resolved the trichosporonous endophthalmitis that was resistant to multiple antifungal drugs. Endophthalmitis due to trichosporonosis is difficult to treat. The administration of AMPH-B is likely to be more effective in treating endophthalmitis due to trichosporonosis when the disease is at an early stage.

Breakthrough infection of Trichosporon asahii during posaconazole treatment in a patient with acute myeloid leukaemia

A neutropenic patient with acute myeloid leukaemia experienced a breakthrough infection of Trichosporon asahii during posaconazole treatment. After treatment was changed to a combination therapy with voriconazole and liposomal amphotericin B, the infection resolved. Posaconazole works effectively as an antifungal prophylaxis and salvage therapy in rare invasive fungal infections. This case however illustrates that breakthrough infections with T. asahii may occur during posaconazole treatment.

Successful Treatment of Breakthrough Trichosporon asahii Fungemia with Voriconazole in a Patient with Acute Myeloid Leukemia

We describe a 55-year-old man with acute myelogenous leukemia who developed breakthrough Trichosporon asahii fungemia during 5 days of micafungin treatment. Although the patient's clinical condition improved considerably after the start of voriconazole treatment, blood culture results remained positive for T. asahii for 3 days, and fever persisted for 7 days thereafter. The patient achieved complete hematological remission, and he received successful consolidation chemotherapy without developing Trichosporon infection with the prophylactic use of voriconazole therapy. This case report illustrates that voriconazole may be useful in the treatment of disseminated T. asahii infection in neutropenic patients.

Cutaneous fungal infections in the oncology patient: recognition and management

There are two main types of fungal infections in the oncology patient: primary cutaneous fungal infections and cutaneous manifestations of fungemia. The main risk factor for all types of fungal infections in the oncology patient is prolonged and severe neutropenia; this is especially true for disseminated fungal infections. Severe neutropenia occurs most often in leukemia and lymphoma patients exposed to high-dose chemotherapy. Fungal infections in cancer patients can be further divided into five groups: (i) superficial dermatophyte infections with little potential for dissemination; (ii) superficial candidiasis; (iii) opportunistic fungal skin infections with distinct potential for dissemination; (iv) fungal sinusitis with cutaneous extension; and (v) cutaneous manifestations of disseminated fungal infections. In the oncology population, dermatophyte infections (i) and superficial candidiasis (ii) have similar presentations to those seen in the immunocompetent host. Primary cutaneous mold infections (iii) are especially caused by Aspergillus, Fusarium, Mucor, and Rhizopus spp. These infections may invade deeper tissues and cause disseminated fungal infections in the neutropenic host. Primary cutaneous mold infections are treated with systemic antifungal therapy and sometimes with debridement. The role of debridement in the severely neutropenic patient is unclear. In some patients with an invasive fungal sinusitis (iv) there may be direct extension to the overlying skin, causing a fungal cellulitis of the face. Aspergillus, Rhizopus, and Mucor spp. are the most common causes. We also describe the cutaneous manifestations of disseminated fungal infections (v). These infections usually occur in the setting of prolonged neutropenia. The most common causes are Candida, Aspergillus, and Fusarium spp. Therapy is with systemic antifungal therapy. The relative efficacies of amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin are discussed. Recovery from disseminated fungal infections is unlikely, however, unless the patient's neutropenia resolves.

Breakthrough Trichosporonosis in Patients with Hematologic Malignancies Receiving Micafungin

BACKGROUND

Micafungin is a newly approved antifungal agent in the echinocandin class that is active against Candida species and Aspergillus species. However, this agent has limited activity against a number of fungi, including Trichosporon species. We describe 4 patients who developed disseminated trichosporonosis during the use of micafungin. No cases of trichosporonosis had been seen in the 2 years prior to January 2003, when micafungin became available in our hospital.

METHODS

We reviewed microbiological records of patients at Kameda General Hospital (Kamogawa City, Chiba, Japan) from 1 January 2002 to 31 July 2005, and identified 4 patients whose blood culture results were positive for Trichosporon species.

RESULTS

Since January 2003, four patients--3 with acute myelocytic leukemia and 1 with myelodysplastic syndrome--developed disseminated trichosporonosis while receiving treatment with micafungin with or without amphotericin B. The initial 2 isolates were identified as Trichosporon beigelii, and the later 2 isolates were identified as Trichosporon asahii. All 4 patients received micafungin, and 2 also received amphotericin B concomitantly. Minimal inhibitory concentrations of micafungin were >16 microg/mL for the 2 isolates available for susceptibility testing. One patient with hematologic recovery (neutrophils >500 cells/mm3) showed elimination of the fungus after receiving treatment with voriconazole. However, the 3 other patients without hematologic or immunological recovery died of disseminated infection.

CONCLUSIONS

The rarity of trichosporonosis in our hospital and its emergence after the introduction of micafungin therapy support the idea that micafungin may exert a significant, selective pressure toward resistant fungi, such as Trichosporon species. Therefore, care should be taken regarding the possibility of trichosporonosis in patients receiving micafungin with or without amphotericin B.

Invasive infections caused by Trichosporon species and Geotrichum capitatum in patients with hematological malignancies: a retrospective multicenter study from Italy and review of the literature

Trichosporonosis is an uncommon but frequently fatal mycosis in immunocompromised patients. A multicenter retrospective study was conducted to characterize cases of proven or probable invasive trichosporonosis diagnosed over the past 20 years in Italian patients with hematological diseases. Of the 52 cases identified, 17 were classified as Trichosporon sp. infections and 35 were attributed to Geotrichum capitatum. Acute myeloid leukemia accounted for 65.4% of the cases. The incidence rates of Trichosporon sp. and G. capitatum infections in acute leukemia patients were 0.4 and 0.5%, respectively. Overall, 76.9% of cases had positive blood cultures. Pulmonary involvement was documented in 26.9% of cases. Death was reported for 57.1% of G. capitatum infections and for 64.7% of Trichosporon sp. infections. A literature review on trichosporonosis in patients with any underlying disease or condition reveals G. capitatum as a predominantly European pathogen, particularly in certain Mediterranean areas, while Trichosporon sp. infections are seen with similar frequencies on all continents. The majority of published Trichosporon sp. and G. capitatum infections occurred in patients with hematological diseases (62.8 and 91.7%, respectively). Well over half of these were suffering from acute leukemia (68 and 84% of patients with Trichosporon sp. and G. capitatum infections, respectively). Crude mortality rates were 77% for Trichosporon spp. and 55.7% for G. capitatum. The optimal therapy for trichosporonosis has yet to be identified; however, in vitro experiences are providing encouraging evidence of the potential role of the new triazoles, in particular, voriconazole.

Disseminated trichosporonosis caused by Trichosporon loubieri

Trichosporonosis is an emerging invasive fungal infection in immunosuppressed patients; a case of disseminated infection caused by Trichosporon loubieri presented confirms its role as a human pathogen.

In vitro susceptibility testing of Geotrichum capitatum: comparison of the E-test, disk diffusion, and Sensititre colorimetric methods with the NCCLS M27-A2 broth microdilution reference method

The in vitro activities of amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole against 23 isolates of Geotrichum capitatum were determined by the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 microdilution method and the Sensititre and agar diffusion methods. Amphotericin B and voriconazole appeared to be the more active drugs. Sensititre showed the highest rates of agreement with the NCCLS M27-A2 method.

Infections due to emerging and uncommon medically important fungal pathogens

The emergence of less common but medically important fungal pathogens contributes to the rate of morbidity and mortality, especially in the increasingly expanding population of immunocompromised patients. These pathogens include septate filamentous fungi (e.g., Fusarium spp., Scedosporium spp., Trichoderma spp.), nonseptate Zygomycetes, the endemic dimorphic pathogen Penicillium marneffei, and non-Cryptococcus, non-Candida pathogenic yeast (e.g., Trichosporon spp.). The medical community is thus called upon to acquire an understanding of the microbiology, epidemiology and pathogenesis of these previously uncommon pathogens in order to become familiar with the options for prevention and treatment.

Invasive infections caused by Blastoschizomyces capitatus and Scedosporium spp

Blastoschizomyces capitatus, Scedosporium prolificans and S. apiospermum are emerging fungal pathogens that may cause disseminated disease in neutropenic patients. They can present as fever resistant to antibiotics and to wide-spectrum antifungal agents, although they may involve almost every organ. The proportion of recovery from blood cultures is high and they are characteristically resistant to most antifungal agents. Prognosis is poor unless patients recover from neutropenia. Voriconazole has good in-vitro activity and is currently the drug of choice for these infections.

Cluster of Trichosporon mucoides in children associated with a faulty bronchoscope

BACKGROUND

Several outbreaks of Pseudomonas aeruginosa infection associated with a specific model of fiberoptic bronchoscope have been reported. In a 3-week period in September 2000, we noticed an increased number of Trichosporon mucoides isolates recovered from bronchoalveolar lavage (BAL) specimens collected at our hospital. We investigated the circumstances surrounding these isolates.

METHODS

Outbreak investigation was conducted, and the medical records of the affected patients were reviewed retrospectively for evidence of positive cultures for T. mucoides from BAL specimens. Specimens collected during the investigation were inoculated onto fungal culture medium and yeasts were identified with API-20C (BioMèrieux-Vitek).

RESULTS

During the 3-week period BAL specimens from six patients yielded growth of T. mucoides. These six high risk patients had emergency bronchoscopy performed as a workup for pneumonia and/or respiratory distress. A Model BF XP-40 bronchoscope (Olympus) had been used in all six patients. Cultures of the bronchoscope (external body and the lumen), bronchoscope disinfector, 2% glutaraldehyde disinfecting solution and water filters/supply were performed. Only fluid from the bronchoscope lumen yielded growth of T. mucoides. Air sample cultures of the bronchoscopy suites were negative. Medical records review disclosed that affected patients were not readmitted with infection with T. mucoides and had no adverse outcomes. The bronchoscope was removed from service and returned to the manufacturer.

CONCLUSION

Routine surveillance and aggressive investigation identified persistent T. mucoides contamination of one bronchoscope. The bronchoscope manufacturer later recalled the BF XP-40 model for corrective revision.

Newer antifungal therapy for emerging fungal pathogens

As the number of immunocompromised patients increases, there is a concomitant increase in the number and diversity of fungal infections. Fungi that were once considered harmless or contaminants are now pathogenic in the immunocompromised host. Often these emerging pathogens are indistinguishable from the more familiar fungal infections; however, they are generally more recalcitrant to conventional antifungal therapies. With the antifungal armamentarium now expanding, the clinician now has many more options for these difficult-to-treat mycoses. We review many of the newer antifungal agents (second-generation triazoles, echinocandins, etc.) as therapeutic options for the recently emerging fungal pathogens.

Successful treatment of Trichosporon mucoides infection with fluconazole in a heart and kidney transplant recipient

Trichosporon species are an emerging cause of infection, particularly among transplant recipients. We report what we believe to be the first case of successful management of disseminated Trichosporon mucoides infection with orally administered fluconazole in a heart and kidney transplant recipient.

Trichosporon loubieri infection in a patient with adult polycystic kidney disease

A 45-year-old man from Nepal with a 13-year history of polycystic kidney disease was diagnosed as suffering from chronic renal failure with end-stage renal disease. After receiving empirical antituberculosis treatment, he was treated with broad-spectrum antibiotics. A left nephrectomy was performed, and after 4 months, he received a kidney transplant. The left kidney was grossly enlarged, with multiple cystic spaces filled with blackish material. Histologic examination of the excised left kidney tissue stained with hematoxylin and eosin and Gomori's methenamine silver stains showed numerous hyaline, septate, fungal hyphae of various lengths, many broken into rectangular arthroconidia in the cystic spaces. Culture of the kidney tissue yielded white, glabrous, yeast-like colonies. Based on its micromorphology, growth at 42 degrees C, and ribosomal DNA (rDNA) sequence analysis, and also sequence analysis of the internal-transcribed-spacer and D1/D2 rDNA regions, the yeast was identified as Trichosporon loubieri. Postsurgically, the patient was treated with amphotericin B and oral itraconazole, followed by maintenance therapy with fluconazole. He remained afebrile and asymptomatic. At the final follow-up, all parameters were found normal and the patient was doing well, with normal renal function reports. This paper presents the first known case of human infection caused by T. loubieri.

Antifungal pharmacodynamic characteristics of amphotericin B against Trichosporon asahii, using time-kill methodology

We determined the MIC of amphotericin B against 45 Trichosporon asahii isolates from various clinical and environmental sources, and used in vitro time-kill methods to characterize the relationship between amphotericin B concentrations and MIC for four representative T. asahii isolates. Amphotericin B had concentration-dependent antifungal activity. MICs ranged from 0.5 to 16 microg/ml, and most T. asahii isolates (76%, 34/45) were inhibited at safely achievable amphotericin B serum concentrations (< or = 2 microg/ml). However, 40% (18/45) of isolates were not killed at these concentrations (MFCs from 1.0 to 32 microg/ml). At concentrations > or = 2 x MIC, amphotericin B exhibited fungicidal activity (< 99.9% reduction in CFU) over a 12-hr time-period; the maximal effect was achieved at > or =4 x MIC. Susceptibility testing confirmed the resistance of T. asahii to amphotericin B, and in vitro pharmacodynamic results also suggest that amphotericin B is not suitable therapy for T. asahii infection.

Breakthrough trichosporonosis in a bone marrow transplant recipient receiving caspofungin acetate

We report a case of invasive trichosporonosis due to Trichosporon beigelii originating in the left wrist of a bone marrow transplant recipient who was receiving caspofungin acetate as prophylaxis against invasive Aspergillus infection. While the patient's neutrophil count was recovering, treatment with fluconazole and amphotericin B lipid complex resulted in a complete clinical response.

Chronic disseminated Trichosporon asahii infection in a leukemic child

We report a case of chronic disseminated Trichosporon asahii infection in a leukemic child. Administration of amphotericin B lipid complex resulted in rapid control and improvement of the initial infection but failed to prevent the development of chronic disseminated disease. Cure was achieved after treatment was changed to a 20-month course of itraconazole. This case report demonstrates that Trichosporon species can cause chronic disseminated disease with a pattern similar to that of disease caused by Candida species.

Case reports. Isolation of two Trichosporon cutaneum strains from urine

Two strains of Trichopsoron cutaneum were isolated from the urine of two male patients. Antifungal susceptibility and cross-reactivity with Cryptococcus antigen latex agglutination text as well as the patients' situation are reported.

Generalized lymphadenopathy caused by Trichosporon asahii in a patient with Job's syndrome

Of the six species of Trichosporon known to cause human infections, T. asahii is the main agent of invasive trichosporonosis. We describe an unusual case of generalized lymphadenopathy due to T, asahii in a 10-year-old boy with Job's syndrome (markedly elevated IgE with eosinophilia). The diagnosis was based on the presence of blastic conidia and hyphal elements breaking into arthroconidia in biopsied tissue of the cervical lymph node and isolation of the causal agent T, asahii in pure culture. The patient responded initially to amphotericin B therapy, but the infection recurred within 4 weeks and did not respond to therapy of liposomal amphotericin B and 5-fluorocytosine for 10 days. The patient left the hospital against medical advice.

Uncommon opportunistic fungi: new nosocomial threats

During the past two decades opportunistic fungal infections have emerged as important causes of morbidity and mortality in patients with severe underlying illnesses and compromised host defenses. While Aspergillus and Candida spp. collectively account for the majority of these infections, recent epidemiological trends indicate a shift towards infections by Aspergillus spp., nonalbicans Candida spp., as well as previously uncommon opportunistic fungi. Apart from an expanding number of different Zygomycetes, previously uncommon hyaline filamentous fungi (such as Fusarium species, Acremonium species, Paecilomyces species, Pseudallescheria boydii, and Scedosporium prolificans), dematiaceous filamentous fungi (such as Bipolaris species, Cladophialophora bantiana, Dactylaria gallopava, Exophiala species, and Alternaria species) and yeast-like pathogens (such as Trichosporon species, Blastoschizomyces capitatus, Malassezia species, Rhodotorula rubra and others) are increasingly encountered as causing life threatening invasive infections that are often refractory to conventional therapies. On the basis of past and current trends, the spectrum of fungal pathogens will continue to evolve in the settings of an expanding population of immunocompromised hosts, selective antifungal pressures, and shifting conditions in hospitals and the environment. An expanded and refined drug arsenal, further elucidation of pathogenesis and resistance mechanisms, establishment of in vitro/in vivo correlations, incorporation of pharmacodynamics, combination- and immunotherapies offer hope for substantial progress in prevention and treatment.

Trichosporon asahii: an unusual cause of invasive infection in neonates

Trichosporon asahii causes white piedra, an infection of hair shafts and onychomycosis in immunocompetent patients, as well as various localized or disseminated invasive infections in immunodeficient hosts. We describe a 26-week gestation 890-g vaginally delivered female neonate who had severe respiratory distress syndrome and on the sixth day of life developed Klebsiella pneumoniae sepsis. At the same time two blood cultures were positive for T. asahii. The neonate was also colonized with T. asahii in the pharynx and perineum. The infant was successfully treated with conventional amphotericin B.

Multidrug-resistant Trichosporon asahii infection of nongranulocytopenic patients in three intensive care units

Trichosporon asahii (Trichosporon beigelii) infections are rare but have been associated with a wide spectrum of clinical manifestations, ranging from superficial involvement in immunocompetent individuals to severe systemic disease in immunocompromised patients. We report on the recent recovery of T. asahii isolates with reduced susceptibility in vitro to amphotericin B (AMB), flucytosine, and azoles from six nongranulocytopenic patients who exhibited risk factors and who developed either superficial infections (four individuals) or invasive infections (two individuals) while in intensive care units. The latter two patients responded clinically and microbiologically to AMB treatment. All six isolates were closely related according to random amplified polymorphic DNA studies and showed 71% similarity by amplified fragment length polymorphism analysis, suggesting a common nosocomial origin. We also review the literature pertaining to T. asahii infections and discuss the salient characteristics of this fungus and recent taxonomic proposals for the genus.