Overview of transplant mycology

Epidemiology, management, and outcome of invasive fungal disease in patients undergoing hematopoietic stem cell transplantation in China: a multicenter prospective observational study

The China Assessment of Antifungal Therapy in Hematological Disease study, the first large-scale observational study of invasive fungal disease (IFD) in China, enrolled 1401 patients undergoing hematopoietic stem cell transplantation (HSCT) (75.2% allogeneic and 24.8% autologous) at 31 hospitals across China. The overall incidence of proven or probable IFD was 7.7% (108 of 1401); another 266 cases (19.0%) were possible IFD. After allogeneic or autologous HSCT, the incidence of proven/probable IFD was 8.9% (94 of 1053) and 4.0% (14 of 348), respectively. Some cases (14 of 108) developed during conditioning before transplantation. The cumulative incidence of proven/probable IFD increased steeply in the first month after transplantation and after 6 months, the incidence was significantly higher in allogeneic than it was in autologous transplant recipients (9.2% versus 3.5%; P = .001) and when stem cells were derived from cord blood or bone marrow and peripheral blood (P = .02 versus other sources). Independent risk factors for proven/probable IFD in allogeneic HSCT were diabetes, HLA-matched unrelated donor, prolonged severe neutropenia (absolute neutrophil count > 500/mm(3) for >14 days), and immunosuppressants (odds ratio, 2.0 to 3.4 for all). Antifungal prophylaxis was independently protective (P = .01). Previous IFD and prolonged severe neutropenia were significant independent risk factors among autologous transplantation patients (P < .01, P = .04, respectively). In total, 1175 (83.9%) patients received antifungal prophylaxis (91.6% triazoles) and 514 (36.7%) were treated in the hospital with therapeutic antifungals (89.1% triazoles; median 27 days). Empirical, pre-emptive, and targeted antifungals were used in 82.3%, 13.6%, and 4.1% of cases, respectively. Overall mortality (13.4%; 188 deaths) was markedly higher in patients with proven (5 of 16; 31.3%), probable (20 of 92; 21.7%), or possible (61 of 266; 22.9%) IFD; allogeneic (171 of 1053; 16.2%) rather than autologous (17 of 348; 4.9%) HSCT and was significantly higher in patients receiving pre-emptive (18.6%) rather than empirical (6.1%) or targeted (9.5%) antifungal therapy (P = .002). Improvements in the selection and timing of prophylactic antifungals would be welcome. Health care providers should remain alert to the increased risk of IFD and associated mortality in allogeneic HSCT recipients and the ongoing risk of IFD even after discharge from the hospital.

Systematic internal transcribed spacer sequence analysis for identification of clinical mold isolates in diagnostic mycology: a 5-year study

The implementation of internal transcribed spacer (ITS) sequencing for routine identification of molds in the diagnostic mycology laboratory was analyzed in a 5-year study. All mold isolates (n = 6,900) recovered in our laboratory from 2005 to 2009 were included in this study. According to a defined work flow, which in addition to troublesome phenotypic identification takes clinical relevance into account, 233 isolates were subjected to ITS sequence analysis. Sequencing resulted in successful identification for 78.6% of the analyzed isolates (57.1% at species level, 21.5% at genus level). In comparison, extended in-depth phenotypic characterization of the isolates subjected to sequencing achieved taxonomic assignment for 47.6% of these, with a mere 13.3% at species level. Optimization of DNA extraction further improved the efficacy of molecular identification. This study is the first of its kind to testify to the systematic implementation of sequence-based identification procedures in the routine workup of mold isolates in the diagnostic mycology laboratory.

Mucormycosis after kidney transplantations: Report of seven cases

This is a report of 7 cases of mucormycosis infections in patients who had undergone transplantation and been admitted in the kidney transplant centre of Baqiyatallah Hospital in Tehran, Iran, from 2002 to 2005. We retrospectively reviewed the hospital records for demographic data, symptoms, diagnostic techniques and outcomes. Five patients were male and 2 female. The mean age of patients was 49.5 y. The time interval between transplantation and disease onset varied greatly (range: 1 month to 4 y). Patients' symptoms were fever (7 cases), respiratory distress (4 cases) and severe headache (3 cases). Suspected patients were evaluated by CT scan, BAL and biopsy and diagnosis confirmed by culture. The final diagnosis was pulmonary mucormycosis in 4 cases, rhino-cerebral mucormycosis in 2 cases and disseminated mucormycosis in 1 case. Despite early and intensive treatment with amphotericin B in all patients and extensive debridement in 3 cases, only 2 patients survived the disease. Mucormycosis is a potentially lethal complication after kidney transplantation. It could occur very early on or very late into the post-transplant period. Despite the results of other studies, the most frequent site of infection in our patients was the lungs.

Infections caused by Candida krusei in five transplant and two surgical patients

BACKGROUND

Candida krusei (Ck) may cause severe infections in immunocompromised hosts and is innately resistant to fluconazole.

PATIENTS AND METHODS

During an 18-month period, seven patients with Ck infection were identified at our center. All were treated in the transplant intensive care unit. Candida isolates were grown on Sabouraud agar, and chromosomal DNA was extracted; clonality was investigated using random amplified polymorphic DNA-polymerase chain reaction with primers M13, OPA-18, and OPE-18.

RESULTS

Among the patients with Ck infection, there were three pancreas recipients with intra-abdominal infection, one liver recipient with cholangitis, one lung recipient with pleural empyema, one patient with pleural empyema after esophageal perforation, and one case of pneumonia in a patient with a ventricular assist device. Treatment consisted of caspofungin (n = 3), voriconazole (n = 1), or a combination of the two (n = 2) together with surgery (n = 3) or pigtail catheter drainage (n = 3). One patient underwent drainage without antifungal treatment, and one patient did not have drainage. The infection was controlled in all cases. The patient with the assist device died from multiple organ dysfunction, the lung recipient died after four months from graft failure, and one pancreas graft was lost. Four patients (57%) harbored the same Ck strain.

CONCLUSION

Solid organ recipients seem to be at particular risk for Ck infections; clonal outbreaks may occur in intensive care units.

Structural and kinetic differences between human and Aspergillus fumigatus D-glucosamine-6-phosphate N-acetyltransferase

Aspergillus fumigatus is the causative agent of aspergillosis, a frequently invasive colonization of the lungs of immunocompromised patients. GNA1 (D-glucosamine-6-phosphate N-acetyltransferase) catalyses the acetylation of GlcN-6P (glucosamine-6-phosphate) to GlcNAc-6P (N-acetylglucosamine-6-phosphate), a key intermediate in the UDP-GlcNAc biosynthetic pathway. Gene disruption of gna1 in yeast and Candida albicans has provided genetic validation of the enzyme as a potential target. An understanding of potential active site differences between the human and A. fumigatus enzymes is required to enable further work aimed at identifying selective inhibitors for the fungal enzyme. In the present study, we describe crystal structures of both human and A. fumigatus GNA1, as well as their kinetic characterization. The structures show significant differences in the sugar-binding site with, in particular, several non-conservative substitutions near the phosphate-binding pocket. Mutagenesis targeting these differences revealed drastic effects on steady-state kinetics, suggesting that the differences could be exploitable with small-molecule inhibitors.

Fungal infections in bone marrow transplant recipients

Invasive fungal infections (IFIs) can cause significant morbidity and mortality in patients after haematopoietic stem cell transplantation. The two most notorious pathogenic fungal species in this group of patients are Candida and Aspergillus. Risk factors for IFIs include: prolonged neutropaenia; fungal overgrowth and conditioning regiment-related mucositis; graft versus host disease; and steroid therapy. Clinical manifestations can be protean, and radiological changes are frequently nonspecific. Diagnostic methods include culture- and nonculture-based techniques. Some experts recommend IFI prophylaxis in the high-risk groups, such as patients with severe graft versus host disease who require prolonged immunosuppressive therapy or patients with a previous history of aspergillosis. Treatment options include therapy with azoles, including the newer agent voriconazole, amphotericin and caspofungin.

Caspofungin for the treatment of fungal infections: a systematic review of randomized controlled trials

During the last decade, owing to the low effectiveness and high toxicity of older antifungals, new antifungal agents have been released to the market for the treatment of patients with fungal infections. Several randomized controlled trials (RCTs) have been designed to evaluate the effectiveness of caspofungin in comparison with other antifungal agents. This review was conducted to examine further the role of caspofungin in the treatment of patients with fungal, mainly Candida, infections. Two reviewers independently performed the literature search, study selection and data extraction from relevant RCTs. A total of six RCTs comparing caspofungin with amphotericin B (deoxycholate in four and liposomal in one RCT) or fluconazole (in one RCT), which studied a total of 1974 patients, were included in our review. Success of the applied treatment in the clinically evaluable patients was achieved in 496/943 (52.6%) of the caspofungin-treated patients and in 381/852 (44.7%) of the amphotericin B- and lipid amphotericin B-treated patients. Discontinuation due to drug toxicity was significantly less common in patients receiving caspofungin than amphotericin B (odds ratio (OR) 0.25, 95% confidence interval (CI) 0.07-0.85, random effects model). Development of nephrotoxicity, hypokalaemia and fever also occurred significantly less often with caspofungin than amphotericin B (OR 0.23, 95% CI 0.14-0.36, fixed effects model; OR 0.3, 95% CI 0.12-0.76, random effects model; and OR 0.26, 95% CI 0.08-0.79, random effects model, respectively). No difference in mortality was noted. Caspofungin was associated with better clinical outcomes (higher cure and fewer adverse effects) than amphotericin B in the treatment of patients with fungal infections.

In VitroActivities of Voriconazole and Five Licensed Antifungal Agents AgainstCandida dubliniensis:Comparison of CLSI M27-A2, Sensititre YeastOne, Disk Diffusion, and Etest Methods

We compared the in vitro activity of six antifungal agents against 62 isolates of Candida dubliniensis by the Clinical Laboratory Standards Institute (CLSI [formerly National Committee for the Clinical Laboratory Standards]) M27-A2, Sensititre YeastOne, disk diffusion, and Etest methods and we studied the effect of the time of reading. For the azoles, voriconazole was the most potent in vitro followed by fluconazole, ketoconazole, and itraconazole. All the isolates were susceptible to amphotericin B and flucytosine. The highest rate of resistance was obtained against itraconazole with a high number of isolates defined as susceptible dose-dependent. At 24 hr, 100% of the isolates were susceptible to ketoconazole, amphotericin B, and flucytosine, 98% susceptible to voriconazole and fluconazole, and 95% for itraconazole. At 48 hr, 100% of the isolates remained susceptible for flucytosine and amphotericin B, 95% for voriconazole, 93% for fluconazole, 90% for ketoconazole, and 82% for itraconazole. The agreement between the CLSI and the other methods was better at 24 than 48 hr.

Epidemiology of Visceral Mycoses in Patients with Leukemia and MDS-Analysis of the Data in Annual of Pathological Autopsy Cases in Japan in 1989, 1993, 1997 and 2001-

To study the changes of visceral mycoses in autopsy cases, data on visceral mycosis cases with leukemia and myelodysplastic syndrome (MDS) reported in the Annual of the Pathological Autopsy Cases in Japan in 1989, 1993, 1997 and 2001 were analyzed. The frequency rate of visceral mycoses with leukemia and MDS was 27.9% (435/1,557) in 1989, 23.0% (319/1,388) in 1993, 22.3% (246/1,105) in 1997 and 25.1% (260/ 1,037) in 2001, which was clearly higher than the rate of cases without leukemia and MDS: 3.4%, 2.7%, 3.5% and 3.7%, respectively. Furthermore, in comparing the rate of mycoses in recipients of stem cell transplantation with that of non-recipients, that of recipients was about 10% higher. The predominant causative agents were Candida and Aspergillus, at approximately the same rate (Candida 33.6%, Aspergillus 33.3%) as in 1989. However, Aspergillus increased conspicuously in 1993 (Candida 22.3% Aspergillus 44.5%), and continued to increase (Candida 22.8%, Aspergillus 50.8% in 1997; Candida 16.9%, Aspergillus 54.2% in 2001). In aspergillosis and zygomycosis, the lung and bronchi comprised the most commonly infected organs: 74.7% and 75.6% of the total cases, respectively. Among a total of 1,260 cases with mycotic infections in the four years studied, acute lymphatic leukemia and acute myeloid leukemia were the major diseases (35.5% and 33.5%, respectively) followed by MDS (29.0%). Given these facts, we emphasize that a greater interest in mycoses should be taken by clinicians, and immunocompromised patients should be protected from opportunistic invasive fungal infections, especially aspergillosis.