The incidence of invasive aspergillosis among solid organ transplant recipients and implications for prophylaxis in lung transplants

Cloning and characterization of a sialidase from the filamentous fungus, Aspergillus fumigatus

A gene encoding a putative sialidase was identified in the genome of the opportunistic fungal pathogen, Aspergillus fumigatus. Computational analysis showed that this protein has Asp box and FRIP domains, it was predicted to have an extracellular localization, and a mass of 42 kDa, all of which are characteristics of sialidases. Structural modeling predicted a canonical 6-bladed beta-propeller structure with the model's highly conserved catalytic residues aligning well with those of an experimentally determined sialidase structure. The gene encoding the putative Af sialidase was cloned and expressed in Escherichia coli. Enzymatic characterization found that the enzyme was able to cleave the synthetic sialic acid substrate, 4-methylumbelliferyl alpha-D-N-acetylneuraminic acid (MUN), and had a pH optimum of 3.5. Further kinetic characterization using 4-methylumbelliferyl alpha-D-N-acetylneuraminylgalactopyranoside revealed that Af sialidase preferred alpha2-3-linked sialic acids over the alpha2-6 isomers. No trans-sialidase activity was detected. qPCR studies showed that exposure to MEM plus human serum induced expression. Purified Af sialidase released sialic acid from diverse substrates such as mucin, fetuin, epithelial cell glycans and colominic acid, though A. fumigatus was unable to use either sialic acid or colominic acid as a sole source of carbon. Phylogenetic analysis revealed that the fungal sialidases were more closely related to those of bacteria than to sialidases from other eukaryotes.

Fungal infections in transplant and oncology patients

Recent shifts in the epidemiology of invasive fungal infections (IFIs) among transplant and oncology populations have led to new recommendations on treatment; however, they have also brought new controversies. New pharmacologic therapies are being studied and guidelines for management of several IFIs have been changed accordingly. More information is being discovered about unique genetic factors that put some transplant recipients at greater risk than others for fungal infection. The role of immunomodulation continues to be investigated, and the delicate balance of maintaining some immune integrity while assuring protection of the graft remains critical. For transplant and oncology patients, the diagnosis and management of IFIs remain challenging, and improving outcomes depends on continued progress in all of these arenas. This article highlights recent advances and important factors to consider when treating transplant and oncology patients with IFIs.

Prophylactic Antifungal Agents Used After Lung Transplantation

Objective:

To review the data supporting available antifungal agents and compare regimens utilized to prevent fungal infection in lung transplant recipients.

Data Sources:

Literature retrieval was accessed through MEDLINE (1950 through October 2009) and United Network for Organ Sharing online database (available data through October 2009), using the terms lung transplantation, prophylaxis, and fungal infection. In addition, reference citations from publications identified were reviewed.

Study Selection And Data Extraction:

All articles or related abstracts in English identified from the data sources above were evaluated. Literature including adult lung transplant recipients who received systemic antifungal prophylaxis to prevent invasive fungal infections (IFIs) was included in the review.

Data Synthesis:

IFIs after lung transplantation remain a common postoperative problem and are associated with high mortality. The lung is the most vulnerable solid organ to be transplanted, as it is the main organ responsible for gas exchange and therefore the high risk for pulmonary-related IFIs. It is most susceptible to developing an IFI, as it serves as a medium for organisms traveling from air to human tissue, potentially causing life-threatening infections. Such infections typically involve Candida and Aspergillus spp. and tend to occur within the first 12 months after transplant. Although there has been an increase in lung transplants performed over the past decade, no standard antifungal prophylactic regimen exists. Literature describing antifungals used to prevent IFI after transplant is scarce, which may be due to a lack of consistency in regimens used between transplant centers. Several regimens have been described utilizing different antifungal agents as both monotherapy and combination therapy. The majority of the literature reviewed here describes aerosolized amphotericin B formulations and azole antifungals demonstrating an overall decreased risk of fungal infection after lung transplantation. It has become the standard of practice to initiate some form of antifungal prophylaxis in these patients.

Conclusions:

The risk of fungal infection after lung transplant is multifactorial and optimal prophylactic regimens should include agents with adequate activity against the most pathogenic fungi.

Fungal infections in pediatric lung transplant recipients: colonization and invasive disease

BACKGROUND

The purpose of this study was to evaluate the epidemiology and investigate the impact of colonization and pulmonary fungal infections (PFIs).

METHODS

In this investigation we performed a retrospective analysis of 55 pediatric lung transplant recipients from 2002 to 2007 at a single institution. Associations between risk factors and time to post-transplant colonization, PFI, and other outcomes were assessed using Cox proportional hazard models.

RESULTS

Although 29 patients had positive pre-transplant colonization, 33 (60%) were colonized post-transplant and 20% (11 subjects) developed proven or probable PFI. In a multivariate model, post-transplant fungal colonization was associated with older age (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.1 to 7.6), cytomegalovirus (CMV) prophylaxis (HR 5.6, 95% CI 1.3 to 24.6) and respiratory viral infection prior to fungal colonization (HR 2.9, 95% CI 1.0 to 8.3).

CONCLUSION

Neither fungal colonization nor PFI was associated with the development of chronic allograft rejection or death.

Antifungal prophylaxis with voriconazole or itraconazole in lung transplant recipients: hepatotoxicity and effectiveness

Invasive fungal infections (IFI) are common after lung transplantation and there are limited data for the use of antifungal prophylaxis in these patients. Our aim was to compare the safety and describe the effectiveness of universal prophylaxis with two azole regimens in lung transplant recipients. This is a retrospective study in lung transplant recipients from July 2003 to July 2006 who received antifungal prophylaxis with itraconazole or voriconazole plus inhaled amphotericin B to compare the incidence of hepatotoxicity. Secondary outcomes include describing the incidence of IFI, clinical outcomes after IFI and mortality. Sixty-seven consecutive lung transplants received antifungal prophylaxis, 32 itraconazole and 35 voriconazole and inhaled amphotericin B. There were no significant differences between groups in the acute physiology and chronic health evaluation (APACHE) score at the time of transplantation, demographic characteristics, comorbidities and concomitant use of hepatotoxic medications. Hepatotoxicity occurred in 12 patients receiving voriconazole and inhaled amphotericin B and in no patients receiving itraconazole (p < 0.001). There was no significant difference between groups with regard to the percentage of transplants with IFI, but one case of zygomycosis occurred in a transplant treated with voriconazole. Voriconazole prophylaxis after lung transplantation was associated with a higher incidence of hepatotoxicity and similar clinical effectiveness when compared to itraconazole.

Invasive mold infections in iatrogenically immunocompromised children: an eight-yr review

IMI are emerging as an important cause of mortality and morbidity among the growing number of immunocompromised children. A retrospective chart review was performed in all patients with a proven diagnosis of IMI over an eight-yr period (1997-2004) at The Hospital for Sick Children, Toronto, Canada to document the incidence, clinical spectrum, microbiology, treatment, and outcome of pediatric IMI. Twenty-eight patients developed IMI over the study period (10 cancer, 12 HCT, and six SOT patients). IMI occurred in 0.51%, 2.2% and 3.2% after a median time of 118, 60 and 71 days, among cancer, HCT and SOT recipients, respectively. Aspergillus spp. infection was diagnosed most commonly (23 patients) and the most common site of infection was the lung (21 patients). Patients at increased risk included those with acute myelogenous leukemia, allogeneic unrelated HCT recipients, graft-versus-host disease, and lung transplant recipients. The mortality after one yr was 60% among cancer patients, 58% among HCT patients, and 16% among SOT patients.

Pinpointing prognostic indicators of fungal infections in transplant patients

A number of advances have been made in the prevention and treatment of invasive fungal infections (IFIs) in transplant recipients. However, despite best clinical efforts, patient outcomes are often disappointing. The study of prognostic indicators of IFI for transplant patients may aid in the development of improved prevention measures, or determine more aggressive treatment pathways. Owing to the rarity of IFI, appropriately powered studies are often difficult to achieve; moreover, a lack of standardized outcome definitions make study comparisons difficult. Herein, prognostic indicators for mortality in transplant patients with IFI are reviewed, with a focus on invasive aspergillosis and invasive candidiasis

Clinical indications for newer antifungal agents

Recent years have seen the release of multiple new systemic antifungal agents, significantly increasing options for the treatment of most serious fungal infections. Newly available drugs include those in the echinocandin class, including caspofungin, micafungin, and anidulafungin, as well as the newer generation triazoles, voriconazole and posaconazole. Ordering of these agents is variably restricted, depending on a given institution's policies, and all are costly. In this review we examine the available evidence and outline the role of newer antifungal medications in several common and/or important situations, including invasive and mucocutaneous Candida infection, febrile neutropenia, invasive aspergillosis, zygomycosis, and endemic mycoses.

Increased mortality after pulmonary fungal infection within the first year after pediatric lung transplantation

BACKGROUND

Risk factors, morbidity and mortality from pulmonary fungal infections (PFIs) within the first year after pediatric lung transplant have not previously been characterized.

METHODS

A retrospective, multicenter study from 1988 to 2005 was conducted with institutional approval from the 12 participating centers in North America and Europe. Data were recorded for the first post-transplant year. The log-rank test assessed for the association between PFI and survival. Associations between time to PFI and risk factors were assessed by Cox proportional hazards models.

RESULTS

Of the 555 subjects transplanted, 58 (10.5%) had 62 proven (Candida, Aspergillus or other) or probable (Aspergillus or other) PFIs within the first year post-transplant. The mean age for PFI subjects was 14.0 years vs 11.4 years for non-PFI subjects (p < 0.01). Candida and Aspergillus species were recovered equally for proven disease. Comparing subjects with PFI (n = 58) vs those without (n = 404), pre-transplant colonization was associated with PFI (hazard ratio [HR] 2.0; 95% CI 0.95 to 4.3, p = 0.067). Cytomegalovirus (CMV) mismatch, tacrolimus-based regimen and age >15 years were associated with PFI (p < 0.05). PFI was associated with any prior rejection higher than Grade A2 (HR 2.1; 95% CI 1.2 to 3.6). Cystic fibrosis, induction therapy, transplant era and type of transplant were not associated with PFI. PFI was independently associated with decreased 12-month survival (HR 3.9, 95% CI 2.2 to 6.8).

CONCLUSIONS

Risk factors for PFI include Grade A2 rejection, repeated acute rejection, CMV-positive donor, tacrolimus-based regimen and pre-transplant colonization.

Current options in antifungal pharmacotherapy

Infections caused by yeasts and molds continue to be associated with high rates of morbidity and mortality in both immunocompromised and immunocompetent patients. Many antifungal drugs have been developed over the past 15 years to aid in the management of these infections. However, treatment is still not optimal, as the epidemiology of the fungal infections continues to change and the available antifungal agents have varying toxicities and drug-interaction potential. Several investigational antifungal drugs, as well as nonantifungal drugs, show promise for the management of these infections.

Evolving strategies in the management of aspergillosis

Aspergillus spp. remain the most common causes of invasive mould infections among patients with hematologic malignancies and recipients of solid-organ and hematopoietic stem-cell transplants. Despite advances in prevention and treatment, invasive aspergillosis continues to be a deadly disease. This paper reviews current approaches to treatment of aspergillosis in adults, including surgical and immune-based strategies, and developments in prophylaxis for aspergillosis in high-risk patient populations.

Results of a multicenter retrospective study of a combined medical and surgical approach to pulmonary aspergillosis in pediatric neutropenic patients

BACKGROUND

Invasive aspergillosis (IA) is a serious problem in patients suffering from hematological malignancies. Surgical resection has been reported to improve disease control and patient survival. There are few reports describing the role of surgery in children with pulmonary IA.

PROCEDURE

From October 1998 to September 2005, 21 patients fulfilled the inclusion criteria. Demographic and clinical data, as well as type and duration of antifungal therapy; surgery and related complications; time elapsing from surgery to resumption of chemotherapy were collected retrospectively through a specially designed form filled in by each investigator.

RESULTS

Eleven males and 10 females, aged between 2 and 17 years underwent one or more surgical lung resections for diagnostic and therapeutic purposes. Surgical complications were reported in three patients. Two patients, who underwent a wedge resection and a lobectomy, respectively, had no fungal lesions detected at surgery. Seventeen of 20 patients with malignancy resumed chemotherapy after a median of 19 days from surgery, range 7-81, and 11 of them underwent hematopoietic stem cell transplantation after a median time of 60 days from surgery, range 19-110. After a median follow-up of 1.7 years, 12 patients are alive while 9 patients have died from progression of their underlying disease.

CONCLUSIONS

This study suggests that the combination of medical antifungal therapy and early surgical excision is a feasible and an effective strategy in pediatric patients with IA. In order to avoid unnecessary surgical procedures, we advise checking the response to antifungal therapy by chest-computed tomography immediately before the date of surgery.

Aspergillosis in children after liver transplantation: Single center experience

Aspergillus infection in immunocompromised patients is associated with high morbidity and mortality. We retrospectively reviewed cases of Aspergillosis (A), in a series of 277 children who received LTx between 1990 and 2006. All children were given antifungal prophylaxis after transplantation. Aspergillosis was identified in 10 cases (3.6%) and diagnosis was confirmed when clinical symptoms were associated with identification of Aspergillus sp. or detection of galactomannan antigen. Incidence of Aspergillosis considerably decreased from 6.9% to 0.6% when liposomal amphotericin B was introduced as prophylaxis in high-risk patients. Mean time since LTx to Aspergillosis was 14.5 days. Histologically, Aspergillosis was diagnosed in two cases. Galactomannan antigen was present in two recipients. Aspergillus infection occurs usually within first 30 days after transplantation as a result of a combination of several risk factors. Following risk factors were observed: multiple antibiotic therapy, prolonged intensive care unit stay, poor graft function, retransplantation, relaparotomies, co-infection. Amphotericin B was administered in all cases. Two patients (20%) died because of Aspergillosis Liposomal Amphotericin B prophylaxis in high-risk children decreases the incidence of Aspergillus infection. High index of suspicion and early diagnosis followed by intensive treatment with amphotericin B facilitates achieving mortality rate lower than presented in other reports.

Safety of aerosolized amphotericin B

Aerosolized delivery of a number of antimicrobial agents has been studied. Despite a theoretical soundness behind this strategy, full consideration of the potential toxicities associated with this mode of administration is imperative. Aerosolized amphotericin B, as both deoxycholate and lipid formulations, has been studied in a variety of high-risk patient populations for prophylaxis and treatment against fungal infections. Although available data remain inconclusive regarding the clinical efficacy of this therapy, variability among results may be due to lack of standardization of administration methods and doses. Akin to the lack of clinical consensus, data regarding the tolerability of this means of amphotericin B delivery are conflicting. This variability may again be accounted for by the lack of standardized means for aerosolized administration. Owing to uncertain clinical benefit and concern for pulmonary toxicities, the use of aerosolized amphotericin B should be limited to clinical investigations at this time.

Invasive fungal infections and antifungal therapies in solid organ transplant recipients

This manuscript will review the risk factors, prevalence, clinical presentation, and management of invasive fungal infections (IFIs) in solid organ transplant (SOT) recipients. Primary literature was obtained via MEDLINE (1966-April 2007) and EMBASE. Abstracts were obtained from scientific meetings or pharmaceutical manufacturers and included in the analysis. All studies and abstracts evaluating IFIs and/or antifungal therapies, with a primary focus on solid organ transplantation, were considered for inclusion. English-language literature was selected for inclusion, but was limited to those consisting of human subjects. Infectious complications following SOT are common. IFIs are associated with high morbidity and mortality rates in this patient population. Determining the best course of therapy is difficult due to the limited availability of data in SOT recipients. Well-designed clinical studies are infrequent and much of the available information is often based on case-reports or retrospective analyses. Transplant practitioners must remain aware of their therapeutic options and the advantages and disadvantages associated with the available treatment alternatives.

Caspofungin-resistant Aspergillus flavus after heart transplantation and mechanical circulatory support: a case report

Invasive aspergillosis (IA) is a severe complication in the post-transplant period in recipients of solid organs. Therefore, early diagnosis and specific therapy of fungal infections in these patients are indispensable. We report the case of a 49-year-old patient, who suffered from IA after cardiac transplantation, which was complicated by post-transplant right heart failure requiring mechanical circulatory support using veno-arterial extracorporeal membrane oxygenation and a right ventricular assist device. Despite antifungal treatment, the patient died 3 weeks after transplantation because of multi-organ failure secondary to IA. The isolated Aspergillus strains exhibited in vitro resistance to caspofungin.

Invasive pulmonary aspergillosis in patients with decompensated cirrhosis: case series

Background

Opportunistic invasive fungal infections are increasingly frequent in intensive care patients. Their clinical spectrum goes beyond the patients with malignancies, and for example invasive pulmonary aspergillosis has recently been described in critically ill patients without such condition. Liver failure has been suspected to be a risk factor for aspergillosis.

Case presentation

We describe three cases of adult respiratory distress syndrome with sepsis, shock and multiple organ failure in patients with severe liver failure among whom two had positive Aspergillus antigenemia and one had a positive Aspergillus serology. In all cases bronchoalveolar lavage fluid was positive for Aspergillus fumigatus. Outcome was fatal in all cases despite treatment with voriconazole and agressive symptomatic treatment.

Conclusion

Invasive aspergillosis should be among rapidly raised hypothesis in cirrhotic patients developing acute respiratory symptoms and alveolar opacities.

Fungal infections in solid organ transplantation

Fungal infections in solid organ transplant recipients continue to be a significant cause of morbidity and mortality. Candida spp. and Aspergillus spp. account for most invasive fungal infections. The incidence of fungal infection varies with type of solid organ transplant. Liver transplant recipients have highest reported incidence of candida infections while lung transplant recipients have highest rate of Aspergillus infections. Recent epidemiological studies suggest the emergence of resistant strains of candida as well as mycelial fungi other than Aspergillus in these patients. The current review incorporates the recent changes in the epidemiology of fungal infections in solid organ transplant recipients and highlights the newer data on the diagnosis, prophylaxis and treatment of fungal infections in these patients.

Inhaled amphotericin B for prophylaxis against invasive Aspergillus infections

OBJECTIVE

To evaluate the available literature describing the use of inhaled amphotericin B for prophylaxis of invasive Aspergillus spp. infections.

DATA SOURCES

A MEDLINE search was conducted (1966-July 2006) using the key terms amphotericin B, inhaled amphotericin B, Aspergillus spp., invasive aspergillosis, solid-organ transplant, neutropenia, and inhalation. Review of the reference lists of the identified articles was also performed.

STUDY SELECTION AND DATA EXTRACTION

Study selection included published trials, case reports, and case series of humans with hematologic disease and solid-organ transplant who used inhaled amphotericin B in the prevention of invasive Aspergillus infections.

DATA SYNTHESIS

Inhaled amphotericin B has been evaluated for the prevention of invasive aspergillosis (IA) infections in neutropenic patients and certain solid-organ transplant recipients. Use of inhaled amphotericin B seems to reduce the incidence of IA in these patients; however, some of the clinical evidence was limited by factors such as small sample sizes, lack of statistical analyses, and lack of power to detect a difference between prophylaxis and control groups. Although the clinical evidence supporting the use of inhaled amphotericin B has some limitations, its use still may be beneficial for the prophylaxis of invasive Aspergillus infections, especially in solid-organ transplant recipients where the evidence is strongest.

CONCLUSIONS

Invasive Aspergillus infections are becoming more prevalent in high-risk populations (eg, patients with malignancies, following bone marrow transplantation, or following solid-organ transplantation). The mortality rates associated with IA are great in these populations, making prophylaxis an important consideration. Inhaled amphotericin B has recently come into vogue as an option for prophylaxis against IA. Some of the data available supports the use of inhaled amphotericin B for the prevention of IA while providing evidence of fewer drug interactions and toxicities associated with other antifungal agents.

Voriconazole prophylaxis in lung transplant recipients

Lung transplant recipients have one of the highest rates of invasive aspergillosis (IA) in solid organ transplantation. We used a single center, nonrandomized, retrospective, sequential study design to evaluate fungal infection rates in lung transplant recipients who were managed with either universal prophylaxis with voriconazole (n = 65) or targeted prophylaxis (n = 30) with itraconazole +/- inhaled amphotericin in patients at high risk (pre- or posttransplant Aspergillus colonization [except Aspergillus niger]). The rate of IA at 1 year was better in lung transplant recipients receiving voriconazole prophylaxis as compared to the cohort managed with targeted prophylaxis (1.5% vs. 23%; p = 0.001). Twenty-nine percent of cases in the targeted prophylaxis group were in patients colonized with A. niger who did not receive itraconazole. A three-fold or higher increase in liver enzymes was noted in 37-60% of patients receiving voriconazole prophylaxis as compared to 15-41% of patients in the targeted prophylaxis cohort. Fourteen percent in the voriconazole group as compared to 8% in the targeted prophylaxis group had to discontinue antifungal medications due to side effects. Voriconazole prophylaxis can be used in preventing IA in lung transplant recipients. Regular monitoring of liver enzymes and serum concentrations of calcineurin inhibitors are required to avoid hepatotoxicity and nephrotoxicity.

Variation in antifungal prophylaxis strategies in lung transplantation

We conducted a survey of 50 lung transplant centers across the world to evaluate the variation in antifungal prophylaxis practices. These 50 centers performed 63% of the world's lung transplants reported in 2001. Eighty-six percent (43/50) of the centers responded to the survey. Sixty-nine percent (30/43) of centers used universal antifungal prophylaxis. Aerosolized amphotericin B deoxycholate (AmBd) alone or in combination with itraconazole was used at 56% (24/43) of centers. The median duration of prophylaxis with aerosolized AmBd and itraconazole was 30 and 90 days, respectively. Seventy-four percent of the centers surveyed agreed to participate in future research prophylaxis protocols, which they felt should include both diagnostic and therapeutic arms. Our survey is the first documentation of the international variation in antifungal prophylactic strategies in lung transplant recipients, and underscores the need for multicenter, randomized trials of antifungal prophylaxis in lung transplant recipients.

Aerosol deposition of lipid complex amphotericin-B (Abelcet) in lung transplant recipients

Lung transplant recipients exhibit a high incidence of invasive aspergillosis. The inhalation of lipid complex amphotericin-B (Abelcet; ABLC) offers a possible prophylactic strategy. The goals of this study were to select the optimal nebulizer delivery system for ABLC and to measure deposited aerosol dose in 12 lung transplant recipients. In vitro testing was performed to select a nebulizer delivery system, and an empirical model was used to estimate lung deposition. Estimated pulmonary doses varied by as much as 2-fold between different nebulizers. Aerosol deposition testing was performed in six single and six double lung recipients, each of whom received one 7 mL (35 mg) nebulized dose of Technetium-labeled ABLC using the selected nebulizer. In single lung recipients, the average deposited doses were 3.9 +/- 1.6 mg (mean +/- S.D.) in the allograft versus 2.1 +/- 1.1 mg in the native lung. Double lung recipients deposited on average 2.8 +/- 0.8 mg (left lung) and 4.0 +/- 1.3 mg (right lung). The drug was well distributed throughout the lungs, but delivery to the native lung was in some cases suboptimal. These studies provide an important precursor to studies of the efficacy of inhaled ABLC as a prophylaxis of invasive aspergillosis after lung transplant.

Infections Complicating Solid Organ Transplantation

The requirements for immune suppression after solid organ transplantation increases the risk of infection with a myriad of organisms. There are many unique and evolving aspects of infection after solid organ transplantation. Advances in immunosuppressive therapy and improved protocols for infection prophylaxis have resulted in changes in the timing and clinical presentation of opportunistic infections. Vigilance in the diagnostic evaluation of suspected infection in the solid organ transplant recipient is essential. This article reviews the basic evaluation and treatment options for many of the infectious conditions peculiar to the immunosuppressed patient.

Micafungin (FK463), alone or in combination with other systemic antifungal agents, for the treatment of acute invasive aspergillosis

BACKGROUND

Micafungin (FK463) is a new lipopeptide compound (echinocandin) with activity against Aspergillus and Candida species. This study evaluated the safety and efficacy of micafungin in patients with proven or probable invasive aspergillosis (IA).

METHODS

A multinational, non-comparative study was conducted to examine proven or probable (pulmonary only) Aspergillus species infection in a wide variety of patient populations. The study employed an open-label design utilizing micafungin alone or in combination with another systemic antifungal agent. Criteria for IA and therapeutic responses were judged by an independent panel.

RESULTS

Of the 331 patients enrolled, only 225 met diagnostic criteria for IA as determined by the independent panel and received at least one dose of micafungin. Patients included 98/225 who had undergone hematopoietic stem cell transplantation (HSCT) (88/98 allogeneic), 48 with graft versus host disease (GVHD), and 83/225 who had received chemotherapy for hematologic malignancy. A favorable response rate at the end of therapy was seen in 35.6% (80/225) of patients. Of those only treated with micafungin, favorable responses were seen in 6/12 (50%) of the primary and 9/22 (40.9%) of the salvage therapy group, with corresponding numbers in the combination treatment groups of 5/17 (29.4%) and 60/174 (34.5%) of the primary and salvage treatment groups, respectively. Of the 326 micafungin-treated patients, 183 (56.1%) died during therapy or in the 6-week follow-up phase; 107 (58.5%) deaths were attributable to IA.

CONCLUSIONS

Micafungin as primary or salvage therapy proved efficacious and safe in high-risk patients with IA, although patient numbers are small in the micafungin-only groups.

Aspergillus fumigatus: Growth and virulence

Aspergillus fumigatus is a ubiquitous fungus that plays an important role in carbon and nitrogen recycling in nature. Because A. fumigatus is thermotolerant, it is a predominant organism during the high-temperature phase of the compost cycle. The ability to grow at elevated temperatures and to utilize numerous varied sources of both carbon and nitrogen to support its growth have made A. fumigatus an important opportunistic pathogen of humans as well as a vital part of the nutrient-recycling ecosystem. Data correlating the growth rate and germination potential of A. fumigatus at 37 degrees C with its pathogenic potential suggest that these are related, both when viewed from a population standpoint and when analyzed on a single gene basis. Nutritional versatility has been cited as an important contributor to virulence as well. Indeed, perturbation of pathways involved with nitrogen or carbon sensing has been shown to reduce virulence in animal models, even when in vitro growth rates have not been altered. Therefore, the remarkable ability of A. fumigatus to grow efficiently under a variety of environmental conditions and to utilize a wide variety of substrates to meet its nutritional needs contributes to its role as the predominant mould pathogen of immunocompromised patients.

Aspergillus pulmonary infections in transplant recipients

Aspergillus infections are increasing in frequency in those undergoing solid organ and hematopoietic stem cell transplantation. The ongoing impact of Aspergillus infection on morbidity and mortality after transplantation makes this subject an area of intense clinical and research interest. This article discusses the evolving epidemiologic features of the infection and its management and diagnosis.

Mediastinal Mass Due to Aspergillus fumigatus After Lung Transplantation: A Case Report

We report a rare case of mediastinal mass caused by Aspergillus fumigatus in a lung transplant recipient. The patient presented 9 months after bilateral lung transplantation for cystic fibrosis with intermittent fevers and new onset atrial fibrillation/flutter caused by a 7-cm mediastinal mass invading the left atrium. The mass was resected, and a prolonged course of voriconazole and caspofungin was given, which resulted in a complete clinical response. Despite long-term suppressive therapy with voriconazole, a relapse occurred 16 months after the initial diagnosis. This case highlights the challenges in the prevention and treatment of invasive aspergillosis in lung transplant recipients.

Incidence of invasive aspergillosis following hematopoietic stem cell and solid organ transplantation: interim results of a prospective multicenter surveillance program

The incidence of invasive aspergillosis was estimated among 4621 hematopoietic stem cell transplants (HSCT) and 4110 solid organ transplants (SOT) at 19 sites dispersed throughout the United States, during a 22 month period from 1 March 2001 through 31 December 2002. Cases were identified using the consensus definitions for proven and probable infection developed by the Invasive Fungal Infections Cooperative Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group of the National Institute of Allergy and Infectious Diseases. The cumulative incidence (CI) of aspergillosis was calculated for the first episode of the infection that occurred within the specified time period after transplantation. To obtain an aggregate CI for each type of transplant, data from participating sites were weighted according to the proportion of transplants followed-up for specified time periods (four and 12 months for HSCT; six and 12 months for SOT). The aggregate CI of aspergillosis at 12 months was 0.5% after autologous HSCT, 2.3% after allogeneic HSCT from an HLA-matched related donor, 3.2% after transplantation from an HLA-mismatched related donor, and 3.9% after transplantation from an unrelated donor. The aggregate CI at 12 months was similar following myeloablative or non-myeloablative conditioning before allogeneic HSCT (3.1 vs. 3.3%). After HSCT, mortality at 3 months following diagnosis of aspergillosis ranged from 53.8% of autologous transplants to 84.6% of unrelated-donor transplants. The aggregate CI of aspergillosis at 12 months was 2.4% after lung transplantation, 0.8% after heart transplantation, 0.3% after liver transplantation, and 0.1% after kidney transplantation. After SOT, mortality at three months after diagnosis of aspergillosis ranged from 20% for lung transplants to 66.7% for heart and kidney transplants. The Aspergillus spp. associated with infections after HSCT included A. fumigatus (56%), A. flavus (18.7%), A. terreus (16%), A. niger (8%), and A. versicolor (1.3%). Those associated with infections after SOT included A. fumigatus (76.4%), A. flavus (11.8%), and A. terreus (11.8%). In conclusion, we found that invasive aspergillosis is an uncommon complication of HSCT and SOT, but one that continues to be associated with poor outcomes. Our CI figures are lower compared to those of previous reports. The reasons for this are unclear, but may be related to changes in transplantation practices, diagnostic methods, and supportive care.