Aspergillus infections in transplant recipients

Aspergillus spondylodiscitis in solid organ transplant recipients

BACKGROUND

Transplantation practices have had a significant effect on the epidemiology of invasive Aspergillosis. Aspergillus spondylodiscitis is rare in transplant recipients. The optimal treatment has yet to be defined because of the rarity of such cases. This article reviews the available literature on Aspergillus spondylodiscitis in solid organ transplant recipients and provides recommendations on its management.

METHODS

We identified 15 cases of Aspergillus spondylodiscitis in transplant recipients. Most patients were heart transplant recipients. Back pain was the mode of presentation in all patients. Most cases were afebrile. The dominant location was the lumbar spine.

RESULTS

Aspergillus fumigatus was responsible for 84.62% of cases and A flavus for 15.38%. The overall recovery rate was 66.67%. Delay in diagnosis remained a major impediment to the successful treatment of spinal aspergillosis. Treatment included antifungal therapy alone or combined with surgery. Initial therapy with voriconazole could lead to better curative effects.

CONCLUSION

Combined medical and operative interventions are recommended for treatment.

Influence of infection by Aspergillus in arterial complications after liver transplantation: evolution and results in 670 transplants

The incidence of fungal complications is frequent among liver transplanted subjects. Between March 1986 and June 2009, we performed 670 liver transplants in 593 patients, including 61% males and an overall average age of 46. The incidence of arterial complications in our center was 5.3% (32/593 patients), including 24 (75%) thromboses, 5 (16%) pseudoaneurysms, 2 anastomotic stenoses, and 1 an iliac graft rupture owing to a mycotic aneurysm. Four patients presented arterial complications associated with Aspergillus sp. Three of them were males of mean age 50 years and 3 had an acute rejection episode. Immunosuppression was cyclosporine (CsA), steroids, and azathioprine. Four arterial complications were diagnosed: 2 thromboses and 2 pseudoaneurysm ruptures. Two patients presented biliary complications associated with the arterial complication and Aspergillus infection. Treatment was expectant in 1 patient, interventional radiology in an other, and retransplantation in the other 2. All patients infected with Aspergillus sp. diad of sepsis and multiorgan failure. Arterial complications posttransplant associated with infection by Aspergillus sp., can be an important cause of retransplantation, sepsis and death.

[Guidelines for the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2011 Update]

The guidelines on the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) are presented. These recommendations are focused on four clinical categories: oncology-haematology patients, solid organ transplant recipients, patients admitted to intensive care units, and children. An extensive review is made of therapeutical advances and scientific evidence in these settings. These guidelines have been prepared according the SEIMC consensus rules by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. Specific recommendations on the prevention of fungal infections in these patients are included.

Natural product-guided discovery of a fungal chitinase inhibitor

Natural products are often large, synthetically intractable molecules, yet frequently offer surprising inroads into previously unexplored chemical space for enzyme inhibitors. Argifin is a cyclic pentapeptide that was originally isolated as a fungal natural product. It competitively inhibits family 18 chitinases by mimicking the chitooligosaccharide substrate of these enzymes. Interestingly, argifin is a nanomolar inhibitor of the bacterial-type subfamily of fungal chitinases that possess an extensive chitin-binding groove, but does not inhibit the much smaller, plant-type enzymes from the same family that are involved in fungal cell division and are thought to be potential drug targets. Here we show that a small, highly efficient, argifin-derived, nine-atom fragment is a micromolar inhibitor of the plant-type chitinase ChiA1 from the opportunistic pathogen Aspergillus fumigatus. Evaluation of the binding mode with the first crystal structure of an A. fumigatus plant-type chitinase reveals that the compound binds the catalytic machinery in the same manner as observed for argifin with the bacterial-type chitinases. The structure of the complex was used to guide synthesis of derivatives to explore a pocket near the catalytic machinery. This work provides synthetically tractable plant-type family 18 chitinase inhibitors from the repurposing of a natural product.

Epidemiology of invasive fungal infections in the mediterranean area

Although Candida species remain the relevant cause of IFI, other fungi (especially moulds) have become increasingly prevalent. In particular, Aspergillus species are the leading cause of mould infections but also Glomeromycota (formerly Zygomycetes) and Fusarium species are increasing in frequency, and are associated with high mortality rates. Many of these emerging infections occur as breakthrough infections in patients treated with new antifungal drugs. The causative pathogens, incidence rate and severity are dependent on the underlying condition, as well as on the geographic location of the patient population. France and Italy show the highest incident rates of Fusarium infections in Europe, following the US, where numbers are still increasing. Scedosporium prolificans, which primarily is found in soil in Spain and Australia, is most frequently isolated from blood cultures in a Spanish hospital. Geotrichum capitatum represents another species predominantly found in Europe with especially high rates in Mediterranean countries. The increasing resistance to antifungal drugs especially of these new emerging pathogens is a severe problem for managing these IFIs.

Fungal microbiota in air-conditioning installed in both adult and neonatal intensive treatment units and their impact in two university hospitals of the central western region, Mato Grosso, Brazil

To evaluate fungal microbiota in air-conditioning units installed in intensive care units in two university hospitals in Cuiaba city, Mato Grosso, central western region of Brazil, 525 solid environmental samples were collected, 285 from Hospital A and 240 from Hospital B. Collections were performed using sterile swabs on air-conditioning unit components: cooling coils, ventilators, and filters. Mycelial fungi identification was achieved by observation of the macroscopic and micromorphological characteristics in different culture mediums (maize meal, oatmeal and potato dextrose agars and malt extract) using the Ridell technique. Eleven genera and 27 distinct species belonging to the hyphomycetes and ascomycetes classes were isolated and identified. The most frequently detected genera in both hospitals were Aspergillus spp, Penicillium spp, and Cladosporium spp. Values for colony-forming units per gram were 64 and 75%, well above the limits recommended by Health Ministry resolution 176/00 at the locations selected for analysis in Hospitals A and B, respectively. In conclusion, evaluation of fungal microbiota in the air-conditioning units indirectly determined that the air quality was compromised in both university hospitals analyzed, which constitutes a risk factor for the acquisition of infection in the intensive care units.

Invasive fungal infections in liver transplantation

Invasive fungal infections (IFIs) in immunocompromised patients, particularly liver transplant recipients, are the subject of increasing clinical attention. Although the overall incidence of fungal infections in liver transplant recipients has declined due to the early treatment of high-risk patients, the overall mortality rate remains high, particularly for invasive candidiasis and aspergillosis. IFIs after liver transplantation are strongly associated with negative outcomes, increasing the cost to recipients. Numerous studies have attempted to determine the independent risk factors related to IFIs and to reduce the morbidity and mortality with empirical antifungal prophylaxis after liver transplantation. Unfortunately, fungal infections are often diagnosed too late; symptoms can be mild and non-specific even with dissemination. Currently, no consensus exists on which patients should receive antifungal prophylaxis, when prophylaxis should be given, which antifungal agents should be used, and what duration is effective. This review highlights the types of IFI, risk factors, diagnosis, antifungal prophylaxis, and treatment after liver transplantation. With the early identification of patients at high risk for IFIs and the development of new molecular diagnostic techniques for early detection, the role of antifungal compounds in fungal infection prophylaxis needs to be established to improve the survival rate and quality of life in liver transplant patients.

Update on the laboratory diagnosis of invasive fungal infections

Recent advances in the management of patients with haematological malignancies and transplant recipients have paralleled an increase in the incidence of fungal diseases due to pathogenic genera such as Candida and Aspergillus and the emergence of less common genera including Fusarium and Zygomycetes. Despite availability of new antifungal agents these opportunistic infections have high mortality. Rapid and reliable species identification is essential for antifungal treatment, but detection of the increasing diversity of fungal pathogens by conventional phenotypic methods remains difficult and time-consuming, and the results may sometimes be inconclusive, especially for unusual species. New diagnostic techniques (e.g., 1,3-beta-d-glucan detection) could improve this scenario, although further studies are necessary to confirm their usefulness in clinical practice.

Tracheobronchial aspergillosis following primary cutaneous aspergillosis in a lung-transplant recipient

Invasive aspergillosis, a major problem during the post-transplant period, typically presents with pneumonia or tracheobronchitis in lung transplant recipients. In contrast, primary cutaneous aspergillosis is very rarely observed in lung-transplant recipients. In this report, we describe a case of tracheobronchial aspergillosis following primary cutaneous aspergillosis in a lung-transplant recipient. Early diagnosis of tracheobronchial aspergillosis is important because occult tracheobronchial aspergillosis can be potentially lethal. Our report suggests that surveillance bronchoscopy may facilitate identification of occult tracheobronchial invasion in lung-transplant recipients with primary cutaneous aspergillosis.

Proteome profiling and functional classification of intracellular proteins from conidia of the human-pathogenic mold Aspergillus fumigatus

Aspergillus fumigatus is a ubiquitously distributed filamentous fungus that has emerged as one of the most serious life-threatening pathogens in immunocompromised patients. The mechanisms for its pathogenicity are poorly understood. Here, we analyzed the proteome of dormant A. fumigatus conidia as the fungal entity having the initial contact with the host. Applying two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), we established a 2-D reference map of conidial proteins. By MALDI-TOF mass spectrometry, we identified a total number of 449 different proteins. We show that 57 proteins of our map are over-represented in resting conidia compared to mycelium. Enzymes involved in reactive oxygen intermediates (ROI) detoxification, pigment biosynthesis, and conidial rodlet layer formation were highly abundant in A. fumigatus spores and most probably account for their enormous stress resistance. Interestingly, pyruvate decarboxylase and alcohol dehydrogenase were detectable in dormant conidia, suggesting that alcoholic fermentation plays a role during dormancy or early germination. Moreover, we show that enzymes for rapid reactivation of protein biosynthesis and metabolic processes are preserved in resting conidia, which therefore feature the potential to immediately respond to an environmental stimulus by germination. The generated data lay the foundations for further proteomic analyses and a better understanding of fungal pathogenesis.

Comparative survival and cost of antifungal therapy: posaconazole versus standard antifungals in the treatment of refractory invasive aspergillosis

BACKGROUND

Refractory invasive aspergillosis (IA) is a life-threatening condition. Cost of treatment, although secondary, is important if newer drugs are to be widely accepted. Posaconazole has been shown to have activity against aspergillosis.

METHODS

Analyses were conducted to compare the effectiveness and cost of posaconazole 800 mg/day with those of standard antifungal therapy, using Walsh et al. 2007 data. All-cause mortality and total drug costs were analyzed for three patient groups: All Refractory, Refractory Non-neutropenic, and Refractory Neutropenic IA Patients. Comparative survival analysis using Kaplan-Meier estimates after censoring data at 28, 42, 84, 182, and 365 days and Cox proportional hazard method was used to estimate hazard rates after controlling for difference in baseline neutropenia. For cost analysis, only antifungal drug acquisition cost was used.

RESULTS

Significantly more of the 94 patients treated with posaconazole remained alive at every time point compared with the 68 external control patients within the All Refractory group (p = 0.0001). Similar results were obtained for the other two groups. For the posaconazole-treated patients mean total drug costs were $11846 (±$12406), $12642 (±$11811), and $8903 (±$14345), and for the external controls total drug costs were $35537 (±$73059), $48097 (±$88702), and $13556 (±$16324) for the All Refractory, Refractory Non-neutropenic, and Neutropenic IA groups, respectively. Key limitations of the study included noninclusion of hospitalization or other drug costs, low patient numbers beyond 84 days, and the fact that the Walsh et al. 2007 study was completed before other newer antifungal agents (such as voriconazole and caspofungin) were available.

CONCLUSIONS

Posaconazole appears to confer a survival benefit and reduced total drug cost compared with standard antifungal therapy, such as amphotericin B (lipid and nonlipid formulations), itraconazole, or both, to treat patients with probable or proven refractory IA.

Invasive aspergillosis in developing countries

To review invasive aspergillosis (IA) in developing countries, we included those countries, which are mentioned in the document of the International Monetary Fund (IMF), called the Emerging and Developing Economies List, 2009. A PubMed/Medline literature search was performed for studies concerning IA reported during 1970 through March 2010 from these countries. IA is an important cause of morbidity and mortality of hospitalized patients of developing countries, though the exact frequency of the disease is not known due to inadequate reporting and facilities to diagnose. Only a handful of centers from India, China, Thailand, Pakistan, Bangladesh, Sri Lanka, Malaysia, Iran, Iraq, Saudi Arabia, Egypt, Sudan, South Africa, Turkey, Hungary, Brazil, Chile, Colombia, and Argentina had reported case series of IA. As sub-optimum hospital care practice, hospital renovation work in the vicinity of immunocompromised patients, overuse or misuse of steroids and broad-spectrum antibiotics, use of contaminated infusion sets/fluid, and increase in intravenous drug abusers have been reported from those countries, it is expected to find a high rate of IA among patients with high risk, though hard data is missing in most situations. Besides classical risk factors for IA, liver failure, chronic obstructive pulmonary disease, diabetes, and tuberculosis are the newly recognized underlying diseases associated with IA. In Asia, Africa and Middle East sino-orbital or cerebral aspergillosis, and Aspergillus endophthalmitis are emerging diseases and Aspergillus flavus is the predominant species isolated from these infections. The high frequency of A. flavus isolation from these patients may be due to higher prevalence of the fungus in the environment. Cerebral aspergillosis cases are largely due to an extension of the lesion from invasive Aspergillus sinusitis. The majority of the centers rely on conventional techniques including direct microscopy, histopathology, and culture to diagnose IA. Galactomannan, β-D glucan test, and DNA detection in IA are available only in a few centers. Mortality of the patients with IA is very high due to delays in diagnosis and therapy. Antifungal use is largely restricted to amphotericin B deoxycholate and itraconazole, though other anti-Aspergillus antifungal agents are available in those countries. Clinicians are aware of good outcome after use of voriconazole/liposomal amphotericin B/caspofungin, but they are forced to use amphotericin B deoxycholate or itraconazole in public-sector hospitals due to economic reasons.

Role of glycogen synthase kinase 3 (GSK-3) in innate immune response of human immature dendritic cells to Aspergillus fumigatus

Dysregulation of the Th1/Th2 cytokine balance and a switch to a Th2 immune response contribute to the development of and the unfavorable outcome from invasive aspergillosis (IA). We explore in this paper the role of glycogen synthase kinase 3 (GSK-3) in human immature dendritic cells (iDCs) relative to infection caused by A. fumigatus by the use of GSK-3 inhibitors (LiCl, SB415286) and RNA interference technology. In iDCs exposed to A. fumigatus germ tubes, inhibition of GSK-3 with LiCl or SB415286, as well as transfection with small interfering RNA, led to markedly elevated expression of the anti-inflammatory cytokine IL-10. In contrast, pro-inflammatory cytokine response was only partially regulated by GSK-3. Screening of patients after allogeneic stem cell transplantation (with or without IA) for the presence of genetic markers (rs334558, rs6438552) in the GSK-3 gene revealed no significant association with an increased risk for IA. In conclusion, GSK-3 might be involved in the regulation of the anti-inflammatory response of iDCs in the context of infections due to A. fumigatus, albeit the exact mechanisms have to be clarified in future experiments.

In vitro antifungal activities of bis(alkylpyridinium)alkane compounds against pathogenic yeasts and molds

Ten bis(alkylpyridinium)alkane compounds were tested for antifungal activity against 19 species (26 isolates) of yeasts and molds. We then determined the MICs and minimum fungicidal concentrations (MFCs) of four of the most active compounds (compounds 1, 4, 5, and 8) against 80 Candida and 20 cryptococcal isolates, in comparison with the MICs of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin, using Clinical Laboratory and Standards Institutes broth microdulition M27-A3 (yeasts) or M38-A2 (filamentous fungi) susceptibility protocols. The compounds were more potent against Candida and Cryptococcus spp. (MIC range, 0.74 to 27.9 microg/ml) than molds (0.74 to 59.7 microg/ml). MICs against Exophiala were 0.37 to 5.9 microg/ml and as low as 1.48 microg/ml for Scedosporium but >or=25 microg/ml for zygomycetes, Aspergillus, and Fusarium spp. Compounds 1, 4, 5, and 8 exhibited good fungicidal activity against Candida and Cryptococcus, except for Candida parapsilosis (MICs of >44 mug/ml). Geometric mean (GM) MICs were similar to those of amphotericin B and lower than or comparable to fluconazole GM MICs but 10- to 100-fold greater than those for the other azoles. GM MICs against Candida glabrata were <1 microg/ml, significantly lower than fluconazole GM MICs (P<0.001) and similar to those of itraconazole, posaconazole, and voriconazole (GM MIC range of 0.4 to 1.23 microg/ml). The GM MIC of compound 4 against Candida guilliermondii was lower than that of fluconazole (1.69 microg/ml versus 7.48 microg/ml; P=0.012). MICs against Cryptococcus neoformans and Cryptococcus gattii were similar to those of fluconazole. The GM MIC of compound 4 was significantly higher for C. neoformans (3.83 mug/ml versus 1.81 microg/ml for C. gattii; P=0.015). This study has identified clinically relevant in vitro antifungal activities of novel bisalkypyridinium alkane compounds.

Epidemiology of invasive aspergillosis and risk factors in non neutropaenic patients

INTRODUCTION

Invasive aspergillosis is a major cause of mortality in allogeneic bone marrow transplant recipients and patients treated for blood malignancies. The diagnostic tools, treatments and preventive strategies, essentially developed for neutropaenic patients, have not been assessed in populations whose immune systems are considered to be competent.

STATE OF THE ART

Beside the standard picture of chronic Aspergillus infection, the incidence of invasive aspergillosis is increasing in non neutropaenic patients, such as those with chronic lung diseases or systemic disease treated with long-term immunosuppressive drugs and solid organ transplant recipients. This study reviews the specific features of invasive aspergillosis in non neutropaenic subjects (NNS) and discusses the value of the diagnostic tools and treatment in this population.

PROSPECTS

A better understanding of the pathophysiology and the epidemiological characteristics of invasive aspergillosis would provide a means of adapting the staging and classification of the disease for NNS.

CONCLUSIONS

Invasive aspergillosis is under diagnosed in NNS who may already be colonised when they receive immunosuppressive treatment; this can lead to an adverse outcome in patients who are considered to be a moderate risk population.

Intrapulmonary pharmacokinetics and pharmacodynamics of micafungin in adult lung transplant patients

Invasive pulmonary aspergillosis is a life-threatening infection in lung transplant recipients; however, no studies of the pharmacokinetics and pharmacodynamics (PKPD) of echinocandins in transplanted lungs have been reported. We conducted a single-dose prospective study of the intrapulmonary and plasma PKPD of 150 mg of micafungin administered intravenously in 20 adult lung transplant recipients. Epithelial lining fluid (ELF) and alveolar cell (AC) samples were obtained via bronchoalveolar lavage performed 3, 5, 8, 18, or 24 h after initiation of infusion. Micafungin concentrations in plasma, ELF, and ACs were determined using high-pressure liquid chromatography. Noncompartmental methods, population analysis, and multiple-dose simulations were used to calculate PKPD parameters. Cmax in plasma, ELF, and ACs was 4.93, 1.38, and 17.41 microg/ml, respectively. The elimination half-life in plasma was 12.1 h. Elevated concentrations in ELF and ACs were sustained during the 24-h sampling period, indicating prolonged compartmental half-lives. The mean micafungin concentration exceeded the MIC90 of Aspergillus fumigatus (0.0156 microg/ml) in plasma (total and free), ELF, and ACs throughout the dosing interval. The area under the time-concentration curve from 0 to 24 h (AUC0-24)/MIC90 ratios in plasma, ELF, and ACs were 5,077, 923.1, and 13,340, respectively. Multiple-dose simulations demonstrated that ELF and AC concentrations of micafungin would continue to increase during 14 days of administration. We conclude that a single 150-mg intravenous dose of micafungin resulted in plasma, ELF, and AC concentrations that exceeded the MIC90 of A. fumigatus for 24 h and that these concentrations would continue to increase during 14 days of administration, supporting its potential activity for prevention and early treatment of pulmonary aspergillosis.

Invasive mould infections: a multi-disciplinary update

Systemic fungal infections remain a significant cause of mortality in neutropenic and immunocompromised patients, despite advances in their diagnosis and treatment. The incidence of such infections is rising due to the use of intensive chemotherapy regimens in patients with solid tumours or haematological cancers, the increasing numbers of allogeneic haematopoietic stem cell and solid organ transplants, and the use of potent immunosuppressive therapy in patients with autoimmune disorders. In addition, the epidemiology of systemic fungal infections is changing, with atypical species such as Aspergillus terreus and zygomycetes becoming more common. Treatment has traditionally focused on empirical therapy, but targeted pre-emptive therapy in high-risk patients and prophylactic antifungal treatment are increasingly being adopted. New treatments, including lipid formulations of amphotericin B, second-generation broad-spectrum azoles, and echinocandins, offer effective antifungal activity with improved tolerability compared with older agents; the potential impact of these treatments is reflected in their inclusion in current treatment and prophylaxis guidelines. New treatment strategies, such as aerosolized lipid formulations of amphotericin B, may also reduce the burden of mortality associated with systemic fungal infections. The challenge is to identify ways of coupling potentially effective treatments with early and reliable identification of patients at highest risk of infection.

Fungal PDR transporters: Phylogeny, topology, motifs and function

The overexpression of pleiotropic drug resistance (PDR) efflux pumps of the ATP-binding cassette (ABC) transporter superfamily frequently correlates with multidrug resistance. Phylogenetic analysis of 349 full-size ( approximately 160kDa) PDR proteins (Pdrps) from 55 fungal species, including major fungal pathogens, identified nine separate protein clusters (A-G, H1a/H1b and H2). Fungal, plant and human ABCG-family Pdrps possess a nucleotide-binding domain [NBD] and a transmembrane domain [TMD] in a family-defining 'reverse' ABC transporter topology [NBD-TMD] that is duplicated [NBD-TMD](2) in full-size fungal and plant Pdrps. Although full-size Pdrps have similar halves indicating early gene duplication/fusion, they show asymmetry of their NBDs and extracellular loops (ELs). Members of cluster F are most symmetric and may be closely related to the evolutionary ancestor of Pdrps. Unique structural elements are predicted, new PDR-specific motifs identified, and the significance of these and other structural features discussed.

Lipid formulations of amphotericin B significantly improve outcome in solid organ transplant recipients with central nervous system cryptococcosis

BACKGROUND

Whether outcome of central nervous system (CNS) cryptococcosis in solid organ transplant recipients treated with lipid formulations of amphotericin B is different from the outcome of the condition treated with amphotericin B deoxycholate (AmBd) is not known.

METHODS

We performed a multicenter study involving a cohort comprising consecutive solid organ transplant recipients with CNS cryptococcosis.

RESULTS

Of 75 patients treated with polyenes as induction regimens, 55 (73.3%) received lipid formulations of amphotericin B and 20 (26.7%) received AmBd. Similar proportions of patients in both groups had renal failure at baseline (P = .94 ). Overall, mortality at 90 days was 10.9% in the group that received lipid formulations of amphotericin B and 40.0% in the group that received AmBd. In univariate analysis, nonreceipt of calcineurin inhibitors (P = .034), renal failure at baseline (P = .016), and fungemia (P = .003) were significantly associated with mortality. Compared with AmBd, lipid formulations of amphotericin B were associated with a lower mortality (P = .007). Mortality did not differ between patients receiving lipid formulations of amphotericin B with or without flucytosine (P = .349). In stepwise logistic regression analysis, renal failure at baseline (odds ratio [OR], 4.61; 95% confidence interval [CI], 1.02-20.80; P = .047) and fungemia (OR, 10.66; 95% CI, 2.08-54.55; P = .004 ) were associated with an increased mortality, whereas lipid formulations of amphotericin B were associated with a lower mortality (OR, 0.11; 95% CI, 0.02-0.57; P = .008).

CONCLUSIONS

Lipid formulations of amphotericin B were independently associated with better outcome and may be considered as the first-line treatment for CNS cryptococcosis in these patients.

Current therapeutic approaches to fungal infections in immunocompromised hematological patients

Invasive fungal infections are significant causes of morbidity and mortality in patients with hematological malignancies. Patients with acute myeloid leukemia and those who have undergone allogeneic hematopoietic stem cell transplantation are at especially high risk. Various fungal agents are responsible for this complication, but Aspergillus spp. and Candida spp. are the most frequently isolated micro-organisms; less commonly, infections could be caused by Zygomycetes or other rare molds or yeasts. Several new systemically-administered antifungal agents have been approved for clinical use since 2001; these agents include liposomal amphotericin B, voriconazole, caspofungin, and posaconazole, and they represent a major advance in antifungal therapy and have improved the prognosis of patients with hematological malignancies. This review focuses on therapeutic aspects of the management of fungal infections in hematological patients.

Drug interactions and adverse events associated with antimycotic drugs used for invasive aspergillosis in hematopoietic SCT

The aim of this study was to assess the frequency of potential drug-drug interactions (pDDIs) and adverse drug events (ADEs) associated with antimycotics in hospitalized patients with hematopoietic SCT (HSCT). Of the 120 HSCT recipients evaluated, 36 received antimycotics. A total of 124 ADEs were recorded in 32 of the 36 patients treated, with 54 ADEs being possibly and 9 probably related to antimycotics. Of the treatments with amphotericin B, 93% were associated with one or more possible and 36% with probable ADEs. The corresponding figures for lipid-based amphotericin B were 100% and 7%, for voriconazole 68% and 11% and for caspofungin 70% and 0%. A total of 57 potentially severe DDIs associated with antimycotics were detected in 31 of the 36 patients. Of these, 14 DDIs were a possible cause of an ADE and 5 (4 times a combination of voriconazole with CYA and once a combination of CYA with conventional amphotericin B) were probably related. Although the prevalence of pDDIs and ADEs is high in HSCT patients, ADEs related with a high probability to treatment with antimycotics are rare. Regarding the high prevalence of pDDIs, our findings underscore the importance of close monitoring of laboratory and clinical parameters, as well as dose adjustment for critical drugs, in patients with HSCT.

Therapy of murine pulmonary aspergillosis with antibody-alliinase conjugates and alliin

Aspergillus fumigatus is an opportunistic fungal pathogen responsible for invasive aspergillosis in immunocompromised individuals. The high morbidity and mortality rates as well as the poor efficacy of antifungal agents remain major clinical concerns. Allicin (diallyl-dithiosulfinate), which is produced by the garlic enzyme alliinase from the harmless substrate alliin, has been shown to have wide-range antifungal specificity. A monoclonal antibody (MAb) against A. fumigatus was produced and chemically ligated to the enzyme alliinase. The purified antibody-alliinase conjugate bound to conidia and hyphae of A. fumigatus at nanomolar concentrations. In the presence of alliin, the conjugate produced cytotoxic allicin molecules, which killed the fungus. In vivo testing of the therapeutical potential of the conjugate was carried out in immunosuppressed mice infected intranasally with conidia of A. fumigatus. Intratracheal (i.t.) instillation of the conjugate and alliin (four treatments) resulted in 80 to 85% animal survival (36 days), with almost complete fungal clearance. Repetitive intratracheal administration of the conjugate and alliin was also effective when treatments were initiated at a more advanced stage of infection (50 h). The fungi were killed specifically without causing damage to the lung tissue or overt discomfort to the animals. Intratracheal instillation of the conjugate without alliin or of the unconjugated monoclonal antibody significantly delayed the death of the infected mice, but only 20% of the animals survived. A limitation of this study is that the demonstration was achieved in a constrained setting. Other routes of drug delivery will be investigated for the treatment of pulmonary and extrapulmonary aspergillosis.

Detection of occult Scedosporium species in respiratory tract specimens from patients with cystic fibrosis by use of selective media

Respiratory samples from cystic fibrosis outpatients were cultured on Sabouraud's dextrose agar (SABD) containing antibiotics, Mycosel, and Scedosporium-selective medium (SceSel+). Thirty-two (14.7%) of 218 specimens from 11/69 (15.9%) patients yielded a Scedosporium sp., most frequently Scedosporium aurantiacum (17/218). Scedosporium was recovered on SceSel+, Mycosel, and SABD from 90.6%, 50.0%, and 46.9% of the specimens tested, respectively.

Pulmonary aspergillosis in patients with chronic obstructive pulmonary disease: incidence, risk factors, and outcome

We describe a large series of patients with chronic obstructive pulmonary disease (COPD) and probable invasive pulmonary aspergillosis (IPA), and the risk factors and incidence of the disease in patients with isolation of Aspergillus from lower respiratory tract samples. From 2000 to 2007, we retrospectively studied all patients admitted with COPD and isolation of Aspergillus (239; 16.3/1000 admissions). Multivariate logistic regression and survival curves were used. Fifty-three patients had probable IPA (3.6 cases of IPA per 1000 COPD admissions). IPA affects at least 22.1% of patients with COPD and isolation of Aspergillus in culture. In 33 of the 53 patients with probable IPA, serum galactomannan was determined; in 14 (42.4%) of these, the result was positive. Five variables were independent predictors of IPA with statistical significance: admission to the intensive-care unit, chronic heart failure, antibiotic treatment received in the 3 months prior to admission, the accumulated dosage of corticosteroids equivalent to >700 mg prednisone received in the 3 months prior to admission, and the similar accumulated dosage of corticosteroids received from admission to the first clinical isolation of Aspergillus. Multivariate analysis gave an area under the curve of 0.925 (95% CI 0.888-0.962; p <0.001). The overall mean survival of the cohort was 64.1% (28.3% for IPA patients and 75.2% for non-IPA patients). The median number of days of survival was 48 (95% CI 33.07-62.92). However, we found statistically significant differences between patients with IPA (29 days; 95% CI 20.59-37.40) and patients without IPA (86 days; 95% CI 61.13-110.86) (log rank, p <0.001).

The clinical importance of bronchoalveolar lavage in allogeneic SCT patients with pneumonia

Patients who undergo allogeneic hematopoietic SCT (HSCT) are prone to pulmonary infections. Between 1998 and 2004, a total of 450 patients underwent HSCT at Karolinska University Hospital, Huddinge. Pneumonia was diagnosed in 167 patients (37%), including 42 children. Bronchoalveolar lavage (BAL) was performed on 68 occasions in 57 patients (six children). In 110 patients (36 children) with pneumonia, BAL was not performed. BAL contributed to the diagnosis in 43 cases (63%) and to relevant findings in 53 cases: bacteria (n=13, 24%), viruses (n=28, 53%) and fungi (n=12, 23%). In 25 cases BAL was negative. In 15 of these cases, BAL was performed >or=4 days after chest X-ray, and in four cases not in the same segment as the infiltrations. The median time between radiographic findings and positive BAL was 2 (0-15) days, and a negative BAL 6 (1-30) days (P<0.001). Antimicrobial treatment was administered to 79% patients with positive findings, and to 92% with negative findings at the time of BAL. No serious complications due to the procedure were reported. BAL resulted in a changed treatment in 32/68 (47%) episodes of pneumonia. To conclude, BAL is a safe and useful diagnostic procedure that should be performed early after the onset of pneumonia following allogeneic HSCT.

Posaconazole in intensive care patients I: invasive fungal infections in surgical intensive care and case presentation

Critically ill patients after extended surgical procedures are at high risk for postoperative infections. Fungal infections play a substantial role for immunocompromised patients, e.g. after solid organ transplantation or under chronic corticoid therapy. Posaconazole, a new broad-spectrum triazole effective against Aspergillus and Candida species as well as many fungi that are resistant to other antifungals, is well tolerated and can be used as an alternative in salvage therapy. Posaconazole can be administered via gavage so that antifungal therapy can be switched from an expensive intravenously applied antifungal to oral posaconazole at an early stage. Two case reports are presented, which show that posaconazole was efficacious and well tolerated following antifungal therapy with another azole. It was administered without difficulty via gavage to a patient receiving artificial respiration and dialysis.

Capítulo 1: diagnóstico laboratorial das micoses pulmonares

Nesta era de imunossupressão e transplantes, é imperativa a comunicação entre médicos e laboratoristas devido ao fato de que o diagnóstico de doenças fúngicas, para esses pacientes, deve ser rápido, o que é complicado e requer a cooperação e colaboração de vários profissionais com distintas especializações. Este artigo revisa as técnicas laboratoriais utilizadas para o diagnóstico de infecções fúngicas pulmonares. Os tópicos abordados incluem: fatores relacionados ao hospedeiro, como resposta imunológica e predisposições anatômicas; colheita, armazenamento, remessa e transporte das amostras; processamento laboratorial; exame microscópico direto; técnicas de coloração, cultivo e identificação fúngica; biossegurança em laboratórios; tropismo e reação teciduais; soromicologia; e detecção de antígenos.

Population structure and diversity of the pathogenic fungus Aspergillus fumigatus isolated from different sources and geographic origins

Fifty-five clinical and environmental Aspergillus fumigatus isolates from Mexico, Argentina, France and Peru were analyzed to determine their genetic variability, reproductive system and level of differentiation using amplified fragment length polymorphism markers. The level of genetic variability was assessed by measuring the percentage of polymorphic loci, number of effective alleles, expected heterozygocity and by performing an association index test (I(A)). The degree of genetic differentiation and variation was determined using analysis of molecular variance at three levels. Using the paired genetic distances, a dendrogram was built to detect the genetic relationship among alleles. Finally, a network of haplotypes was constructed to determine the geographic relationship among them. The results indicate that the clinical isolates have greater genetic variability than the environmental isolates. The I(A) of the clinical and environmental isolates suggests a recombining population structure. The genetic differentiation among isolates and the dendrogram suggest that the groups of isolates are different. The network of haplotypes demonstrates that the majority of the isolates are grouped according to geographic origin.

Secondary cutaneous aspergillosis disseminated from the lungs of a patient with asthma on 1 month steroid treatment

Cutaneous aspergillosis is very rare and occurs predominantly in transplant patients. Here, we report a 55-year-old female who underwent steroid treatment for 1 month and developed secondary cutaneous aspergillosis from pulmonary aspergillosis due to Aspergillus fumigatus.