Invasive aspergillosis. Disease spectrum, treatment practices, and outcomes. I3 Aspergillus Study Group

Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Morbidity and mortality caused by invasive Aspergillus infections are increasing. This is because of the higher number of patients with malignancies treated with intensive immunosuppressive therapy regimens as well as their improved survival from formerly fatal bacterial infections, and the rising number of patients undergoing allogeneic haematopoietic stem cell or organ transplantation. Early initiation of effective systemic antifungal treatment is essential for a successful clinical outcome in these patients; however, clinical clues for diagnosis are sparse and early microbiological proof of invasive aspergillosis (IA) is rare. Clinical diagnosis is based on pulmonary CT scan findings and non-culture based diagnostic techniques such as galactomannan or DNA detection in blood or bronchoalveolar lavage samples. Most promising outcomes can be expected in patients at high risk for aspergillosis in whom antifungal treatment has been started pre-emptively, backed up by laboratory and imaging findings. The gold standard of systemic antifungal treatment is voriconazole, which has been proven to be significantly superior to conventional amphotericin B and has led to a profound improvement of survival rates in patients with cerebral aspergillosis. Liposomal amphotericin B at standard dosages appears to be a suitable alternative for primary treatment, while caspofungin, amphotericin B lipid complex or posaconazole have shown partial or complete response in patients who had been refractory to or intolerant of primary antifungal therapy. Combination therapy with two antifungal compounds may be a promising future strategy for first-line treatment. Lung resection helps to prevent fatal haemorrhage in single patients with pulmonary lesions located in close proximity to larger blood vessels, but is primarily considered for reducing the risk of relapse during subsequent periods of severe immunosuppression. Strict reverse isolation appears to reduce the incidence of aspergillosis in allogeneic stem cell transplant recipients and patients with acute myeloid leukaemia undergoing aggressive anticancer therapy. Well designed, prospective randomised studies on infection control measures effective to prevent aspergillosis are lacking. Prophylactic systemic antifungal treatment with posaconazole significantly improves survival and reduces IA in acute myeloid leukaemia patients and reduces aspergillosis incidence rates in patients with intermediate-to-severe graft-versus-host reaction emerging after allogeneic haematopoietic stem cell transplantation. Voriconazole prophylaxis may be suitable for prevention of IA as well; however, the results of large clinical trials are still awaited.

CNS aspergillosis: recognition, diagnosis and management

Early diagnosis of CNS aspergillosis requires a high degree of clinical suspicion, because there are no typical clinical symptoms or CSF findings. Clinical features are usually dramatic and tend to progress rapidly. Changes in mental status, hemiparesis and seizures are most common, but other nonspecific neurological features may occur and should always be an indication for neuroradiological examination in high-risk patients, in order to allow early initiation of antifungal therapy. Low density lesions with little or no mass effect and minimal or no contrast enhancement on CT scans that are usually more numerous on MRI and show intermediate signal intensity within high-signal areas on T2-weighted images, may suggest CNS aspergillosis. Cerebral lesions in CNS aspergillosis are often located not only in the cerebral hemispheres but also in the basal ganglia, thalami, corpus callosum and perforator artery territories. There is frequently a lack of contrast enhancement or perifocal oedema, due to the immunosuppressed status of the patient. A definite diagnosis requires brain tissue for histopathological analysis. However, neurosurgery is often not feasible, so that any of the neuroradiological findings mentioned above should raise the suspicion of CNS aspergillosis in immunocompromised patients and lead to early initiation of antifungal therapy. In the past, amphotericin B-based therapy was the treatment of choice for CNS aspergillosis, but this treatment produced negligible effects. Recently, voriconazole has been reported to be more effective than amphotericin B in the treatment of invasive aspergillosis. Response rates of about 35% have been achieved with voriconazole in patients with CNS aspergillosis. Combination therapy with antifungal agents, such as voriconazole plus caspofungin or liposomal amphotericin B, is being investigated in vitro and in animal models, and optimistic results have been observed. A combined medical and neurosurgical treatment should be considered in all patients with this disease.

Management of invasive pulmonary aspergillosis in non-neutropenic critically ill patients

During recent years, a rising incidence of invasive pulmonary aspergillosis (IPA) in non-neutropenic critically ill patients has been reported. Critically ill patients are prone to develop disturbances in immunoregulation during their stay in the ICU, which render them more vulnerable for fungal infections. Risk factors such as chronic obstructive pulmonary disease (COPD), prolonged use of steroids, advanced liver disease, chronic renal replacement therapy, near-drowning and diabetes mellitus have been described. Diagnosis of IPA may be difficult and obtaining histo- or cytopathological demonstration of the fungus in order to meet the gold standard for IPA is not always feasible in these patients. Laboratory markers used as a non-invasive diagnostic tool, such as the galactomannan antigen test (GM), 1,3-beta-glucan, and Aspergillus PCR, show varying results. Antifungal therapy might be considered in patients with persistent pulmonary infection who exhibit risk factors together with positive cultures or sequentially positive GM and Aspergillus PCR in serum, in whom voriconazole is the drug of choice. The benefit of combination antifungal therapy lacks sufficient evidence so far, but this treatment might be considered in patients with breakthrough infections or refractory disease.

Fungal infections in recipients of hematopoietic stem cell transplants: results of the SEIFEM B-2004 study--Sorveglianza Epidemiologica Infezioni Fungine Nelle Emopatie Maligne

BACKGROUND

The purpose of our study was to evaluate the incidence and outcome of invasive fungal infection (IFI) among patients who underwent autologous or allogeneic hematopoietic stem cell transplantation (HSCT) at 11 Italian transplantation centers.

METHODS

This cohort-retrospective study, conducted during 1999-2003, involved HSCT patients admitted to 11 tertiary care centers or university hospitals in Italy, who developed IFIs (proven or probable).

RESULTS

Among 3228 patients who underwent HSCT (1249 allogeneic HSCT recipients and 1979 autologous HSCT recipients), IFI occurred in 121 patients (overall incidence, 3.7%). Ninety-one episodes (2.8% of all patients) were due to molds, and 30 (0.9%) were due to yeasts. Ninety-eight episodes (7.8%) occurred among the 1249 allogeneic HSCT recipients, and 23 (1.2%) occurred among the 1979 autologous HSCT recipients. The most frequent etiological agents were Aspergillus species (86 episodes) and Candida species (30 episodes). The overall mortality rate was 5.7% among allogeneic HSCT recipients and 0.4% among autologous HSCT recipients, whereas the attributable mortality rate registered in our population was 65.3% (72.4% for allogeneic HSCT recipients and 34.7% for autologous HSCT recipients). Etiology influenced the patients' outcomes: the attributable mortality rate for aspergillosis was 72.1% (77.2% and 14.3% for allogeneic and autologous HSCT recipients, respectively), and the rate for Candida IFI was 50% (57.1% and 43.8% for allogeneic and autologous HSCT recipients, respectively).

CONCLUSIONS

IFI represents a common complication for allogeneic HSCT recipients. Aspergillus species is the most frequently detected agent in these patients, and aspergillosis is characterized by a high mortality rate. Conversely, autologous HSCT recipients rarely develop aspergillosis, and the attributable mortality rate is markedly lower. Candidemia was observed less often than aspergillosis among both allogeneic and autologous HSCT recipients; furthermore, there was no difference in either the incidence of or the attributable mortality rate for candidemia among recipients of the 2 transplant types.

Occupational risk assessment of aspergillosis after renal transplantation

Returning to work after transplantation is a much-discussed topic today, especially as a measure to avoid permanent work disability. Many transplant patients regain their ability to work 2-6 months after transplantation. However, returning to work should not endanger their health. This means that occupational risks such as occupational exposure to Aspergillus spores must be evaluated. We evaluated the community-acquired aspergillosis risk and in particularly the occupational aspergillosis risk, using the example of a 39-year-old construction worker immunosuppressed after renal transplantation. On one hand the risk is linked to the exposure to microorganisms that the individual is likely to be subjected to, and on the other hand to the factors that modify his state of susceptibility or resistance to these infectious agents. The necessity of immunosuppressive therapy after transplantation elevates the aspergillosis risk, especially 1-6 months after transplantation. There are many professions in which exposure to Aspergillus spores can occur. The risk of acquiring aspergillosis at work exists, but is not quantifiable today. Nevertheless, the risk should be minimized during the period of vulnerability by preventive measures such as restriction of certain activities, changing work methods and reorganizing the work day to adapt to the risk, and wearing personal protective equipment, as well as attention to information about aspergillosis risk and about the likelihood of exposure in the patient's professional and leisure activities.

Aspergillus vertebral osteomyelitis in chronic leukocyte leukemia patient diagnosed by a novel panfungal polymerase chain reaction method

BACKGROUND CONTEXT

Vertebral osteomyelitis and disciitis caused by Aspergillus spp is a rare event. Early diagnosis and early antifungal therapy are critical in improving the prognosis for these patients. The diagnosis of invasive fungal infections is, in many cases, not straightforward and requires invasive procedures so that histological examination and culture can be performed. Furthermore, current traditional microbiological tests (ie, cultures and stains) lack the sensitivity for diagnosis of invasive aspergillosis.

PURPOSE

To present a case of vertebral osteomyelitis caused by Aspergillus spp diagnosed using a novel polymerase chain reaction (PCR) assay.

STUDY DESIGN

Case report.

METHODS

Aspergillus DNA was detected in DNA extracted from the necrotic bone tissue by using a "panfungal" PCR novel method.

RESULTS

Treatment with voriconazole was started based on the diagnosis.

CONCLUSION

Using this novel technique enabled us to diagnose accurately an unusual bone pathogen that requires a unique treatment.

Primary invasive aspergillosis of the digestive tract: report of two cases and review of the literature

Background:

Disseminated aspergillosis is thought to occur as a result of vascular invasion from the lungs with subsequent bloodstream dissemination, and portals of entry other than sinuses and/or the respiratory tract remain speculative.

Methods:

We report two cases of primary aspergillosis in the digestive tract and present a detailed review of eight of the 23 previously-published cases for which detailed data are available.

Results and Conclusion:

These ten cases presented with symptoms suggestive of typhlitis, with further peritonitis requiring laparotomy and small bowel segmental resection. All cases were characterized by the absence of pulmonary disease at the time of histologically-confirmed gastrointestinal involvement with vascular invasion by branched Aspergillus hyphae. These cases suggest that the digestive tract may represent a portal of entry for Aspergillus species in immunocompromised patients.

Successful treatment with voriconazole of Aspergillus brain abscess in a boy with medulloblastoma

Invasive aspergillosis is an increasing problem in immuno-incompetent patients after prolonged steroid therapy, cancer radio-chemotherapy, and bone marrow or solid organ transplantation. Cerebral aspergillosis is a well-described complication of the invasive aspergillosis but only in rare cases, the brain is the sole site of infection. Despite increasing availability of antifungal drugs, the prognosis of cerebral aspergillosis is poor. We report on an 11-year-old boy with medulloblastoma in the area of the fourth ventricle. Following tumor surgery and radio-chemotherapy, several abscess-like structures occurred in the operating field. After incomplete abscess, resection histology and culture confirmed a localized Aspergillus fumigatus infection. The initial treatment of the Aspergillus fumigatus infection with conventional amphotericin B failed, and treatment with the triazole voriconazole was started. Intravenous treatment with voriconazole resulted in a reduction of the Aspergillus fumigatus abscess. After switching to oral ambulatory therapy, the Aspergillus fumigatus abscess increased in size. To improve treatment, voriconazole dosage was adapted to reach drug concentrations in cerebrospinal fluid (CSF) above the minimal fungicidal concentration and plasma specimens. During the concentration-controlled voriconazole therapy for a period of 18 months, a complete response was achieved.

Fatal brain infection caused by Aspergillus glaucus in an immunocompetent patient identified by sequencing of the ribosomal 18S–28S internal transcribed spacer

Cerebral aspergillosis has rarely been reported in immunocompetent patients. We herein describe a unique case of cerebral aspergillosis in a healthy adult that led to his death despite aggressive antifungal therapy. Sequencing of ribosomal 18S-28S internal transcribed spacer identified the organism as Eurotium herbariorum, the teleomorph of Aspergillus glaucus.

Treatment of invasive pulmonary aspergillosis in neutropenic patients by additional bronchoscopic amphotericin B instillation

BACKGROUND

Invasive pulmonary aspergillosis (IPA) remains a life-threatening condition despite systemic antifungal therapy.

OBJECTIVES

This retrospective analysis investigated whether additional bronchoscopic instillation of amphotericin B (amB) would improve efficacy of antifungal treatment in patients with haematological malignancies suffering from IPA.

METHODS

Twenty patients (40.6 +/- 14.2 years, 14 male) with preceding chemotherapy, bone marrow or stem cell transplantation complicated by severe IPA who did not respond sufficiently to systemic antifungal therapy were additionally treated by repeated bronchoscopic instillations of amB solution (91 instillations, on average 4.6 +/- 2.2 instillations per patient over a period of 24.1 +/- 21.0 days). Therapeutic response to this combined treatment regimen was monitored by chest X-ray and CT scan.

RESULTS

The mean infiltration sizes during systemic antifungal therapy alone (mean duration 11.9 +/- 9.9 days) did not change significantly. However, after additional bronchoscopic instillation of amB solution infiltration sizes were reduced significantly (p < 0.05). A total resolution of infiltrates was seen in 3 and a partial reduction in 13 of 20 patients. Mean duration of total antifungal treatment was 50.1 +/- 24.0 days. The mean follow-up period was 34.1 +/- 31.2 months. The IPA-related mortality rate was 18.8% (3 of 16 patients).

CONCLUSIONS

Additional bronchoscopic instillation of amB may improve the efficacy of systemic antifungal therapy in patients with haematological malignancies complicated by severe IPA. Bronchoscopic instillation of amB should be considered as an additional treatment option in cases with IPA unresponsive to systemic therapy.

Antimicrobial resistance prevention initiative--an update: proceedings of an expert panel on resistance

Antimicrobial resistance is a growing problem that complicates the treatment of important nosocomial and community-acquired infections. It is a worldwide problem that spans the range of human pathogens, including bacteria, fungi, and viruses. This update from the Antimicrobial Resistance Prevention Initiative (ARPI) provides a review of some important trends in antibiotic, antifungal, and antiviral resistance. Areas of focus include multidrug-resistant bacteria in the hospital setting; the growing problem of community-acquired methicillin-resistant Staphylococcus aureus; triazole and polyene resistance in nosocomial infections caused by non-Candida albicans or Aspergillus species, and the utility of in vitro susceptibility testing for these fungal infections; antiviral resistance in alpha- or beta-herpesviruses causing genital herpes or cytomegalovirus infection in immunocompromised hosts; and concerns about a possible pandemic involving avian influenza A and the importance of minimizing emergence of resistant strains of this highly pathogenic virus. The challenges in each area are different, but the general keys to addressing the growing problem of antimicrobial resistance continue to be responsible antimicrobial stewardship and the development of newer antimicrobial agents.

Differential fungicidal activities of amphotericin B and voriconazole against Aspergillus species determined by microbroth methodology

Antifungal agents may differ in their fungicidal activities against Aspergillus spp. In order to compare the fungicidal activities of voriconazole and amphotericin B against 40 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, we developed a new microbroth colorimetric method for assessing fungicidal activities and determining minimal fungicidal concentrations (MFCs). This methodology follows the antifungal susceptibility testing reference method M-38A for MIC determination. After drug removal and addition of fresh medium, growth of viable conidia adhering to the bottoms of the microtitration wells was assessed by a colorimetric assay of metabolic activity after 24 h of incubation. The new method was faster (six times), reproducible (92 to 97%), and in agreement with culture-based MFCs (91 to 100%). Differential fungicidal activities of voriconazole and amphotericin B were found among the three Aspergillus species, with A. fumigatus and A. flavus having the lowest (1 and 2 mg/liter, respectively) and A. terreus the highest (>16 mg/liter) median amphotericin B MFCs; A. flavus had a lower median voriconazole MFC (4 mg/liter) than the other species (>8 mg/liter; P < 0.05). Amphotericin B was fungicidal (MFC/MIC </= 4) against all A. fumigatus and A. flavus isolates but no A. terreus isolates, whereas voriconazole was fungicidal against 82% of A. flavus isolates and fungistatic (MFC/MIC > 4) against 94% of A. fumigatus and 84% of A. terreus isolates. The new methodology revealed a concentration-dependent sigmoid pattern of fungicidal effects, indicating that fungicidal activity is not an all-or-nothing phenomenon and that some degree of fungicidal action can be found even for agents considered fungistatic based on the MFC/MIC ratio.

Invasive aspergillosis in the intensive care unit

Data regarding the incidence of invasive aspergillosis (IA) in the intensive care unit (ICU) are scarce, and the incidence varies. An incidence of 5.8% in a medical ICU has been reported. The majority of patients did not have a hematological malignancy, and conditions such as chronic obstructive pulmonary disease and liver failure became recognized as risk factors. Diagnosis of IA remains difficult. Mechanical ventilation makes it difficult to interpret clinical signs, and radiological diagnoses are clouded by underlying lung pathologies. The significance of a positive respiratory culture result is greatly uncertain, because cultures of respiratory specimens have low sensitivity (50%) and specificity (20%-70%, depending on whether the patient is immunocompromised). The use of serologic markers has never been validated in an ICU population. Limited experience with the detection of galactomannan in bronchoalveolar lavage fluid specimens has yielded promising results. Because of a delay in the diagnosis of IA, the mortality rate exceeds 50%. Recently, our therapeutic armamentarium against IA has improved. Data concerning the safety and efficacy of new antifungal agents in the ICU setting, however, are lacking.

Ability to grow on lipids accounts for the fully virulent phenotype in neutropenic mice of Aspergillus fumigatus null mutants in the key glyoxylate cycle enzymes

Incidence and mortality rates of invasive aspergillosis clearly indicate the need of novel antifungals to treat patients suffering from this disease. Fungal proteins playing a crucial role in pathogenesis and with no orthologue in human cells are considered as primary therapeutic targets for the development of new antifungals with a high therapeutic index, one of the major drawbacks of the standard antifungal therapy, so far. In this work, we have analyzed the role in pathogenesis of the key enzymes of the Aspergillus fumigatus glyxoxylate cycle, isocitrate lyase and malate synthase, two possible candidates to primary therapeutic targets in this fungus. Deletion strains lacking isocitrate lyase (DeltaacuD strains) or malate synthase (DeltaacuE mutants) were constructed in this work. The Neurospora crassa pyr-4 gene was used as the replacing marker in gene deletion experiments. The pathogenicities of DeltaacuD and DeltaacuE mutants were tested in neutropenic mice and compared with those of two reference wild-type isolates A. fumigatus 237 and A. fumigatus 293. Interestingly, virulence and cytological studies clearly indicated the dispensability of the A. fumigatus glyoxylate cycle for pathogenicity. In addition, these results suggested the suitability of the pyr-4 gene as a valuable replacing marker for virulence studies in this fungus, a fact that was further confirmed by gene expression analyses. Finally, growth tests were performed to investigate the germination and growth of the DeltaacuD and DeltaacuE strains in nutrient deprivation environments, resembling the conditions that A. fumigatus conidia face after phagocytosis. Results obtained in this work strongly suggest that the ability to grow on lipids (triglycerides) of A. fumigatus isocitrate lyase and malate synthase deletion strains accounts for their fully virulent phenotype.

Aspergillus oryzae peritonitis in CAPD: case report and review of the literature

Fungal peritonitis is a rare, but serious, complication of continuous ambulatory peritoneal dialysis (CAPD). We report a case of peritonitis caused by Aspergillus oryzae in a man on CAPD therapy who was treated successfully with amphotericin B and caspofungin, followed by itraconazole and removal of the peritoneal catheter. A oryzae was identified by using sequence analysis of the ribosomal DNA genes. Of 10 reported cases since 2003, the mortality rate was 30%. Removal of the CAPD catheter and systemic antimycotic therapy are essential to achieve clinical cure in patients with fungal CAPD-related peritonitis.

Central nervous system aspergillosis in children: a systematic review of reported cases

OBJECTIVE

Central nervous system (CNS) aspergillosis is a life-threatening disease that has had a published mortality of >80%. Little is known about this serious infection in the pediatric population. We conducted this study to analyze characteristics of CNS aspergillosis in infants and children.

METHODS

The English literature was reviewed and all CNS aspergillosis cases in patients younger than 18 years of age were analyzed.

RESULTS

Ninety cases were recorded up to June 2005. The median age of the patients was 9 years, ranging from 18 days to 18 years (15.6% younger than 1 year). CNS aspergillosis most commonly presented as brain abscess(es), either single or multiple. While prematurity was the predominant underlying condition among infants, leukemia was the most frequent underlying disease in children. Aspergillus fumigatus was isolated from 75.5% of the cases. The overall mortality in published cases was 65.4%. In multivariate analysis, surgical treatment was independently associated with survival.

CONCLUSION

CNS aspergillosis in infants and children predominantly presents as brain abscess(es) and has significantly better outcome compared to published adult data. The findings of this systematic review could assist future investigations for improved outcome of this life-threatening infection in pediatric patients.

Thymosin alpha1: an endogenous regulator of inflammation, immunity, and tolerance

Thymosin alpha1 (Talpha1), first described and characterized by Allan Goldstein in 1972, is used worldwide for the treatment of some immunodeficiencies, malignancies, and infections. Although Talpha1 has shown a variety of effects on cells and pathways of the immune system, its central role in modulating dendritic cell (DC) function has only recently been appreciated. As DCs have the ability to sense infection and tissue stress and to translate collectively this information into an appropriate immune response, an action on DCs would predict a central role for Talpha1 in inducing different forms of immunity and tolerance. Recent results have shown that Talpha1: (a) primed DCs for antifungal Th1 resistance through Toll-like receptor (TLR)/MyD88-dependent signaling and this translated in vivo in protection against aspergillosis; (b) activated plasmacytoid DCs (pDC) via the TLR9/MyD88-dependent viral recognition, thus leading to the activation of interferon regulatory factor 7 and the promotion of the IFN-alpha/IFN-gamma-dependent effector pathway, which resulted in vivo in protection against primary murine cytomegalovirus infection; (c) induced indoleamine 2,3-dioxygenase activity in DCs, thus affecting tolerization toward self as well as microbial non-self-antigens, and this resulted in vivo in transplantation tolerance and protection from inflammatory allergy. Talpha1 is produced in vivo by cleavage of prothymosin alpha in diverse mammalian tissues. Our data qualify Talpha1 as an endogenous regulator of immune homeostasis and suggest that instructive immunotherapy with Talpha1, via DCs and tryptophan catabolism, could be at work to control inflammation, immunity, and tolerance in a variety of clinical settings.

Poor efficacy of amphotericin B-based therapy in CNS aspergillosis

Recently, improved response and survival rates in patients treated with voriconazole and neurosurgery for central nervous system (CNS) aspergillosis have been reported. We assessed retrospectively the outcome in 17 patients with definite or probable CNS aspergillosis treated with amphotericin B alone (n = 15) or in combination with 5-fluorocytosine (n = 3) or itraconazole (n = 2). Four patients underwent neurosurgery. The mortality rate was 100% with a median survival of only 10 days (range: 3-60) after onset of first symptoms or first radiological evidence of CNS aspergillosis. In conclusion, treatment with amphotericin B and itraconazole has negligible efficacy in CNS aspergillosis.

Caspofungin as salvage monotherapy for invasive aspergillosis in patients with haematological malignancies or following allogeneic stem cell transplantation: efficacy and concomitant cyclosporin A

Caspofungin (CAS) has shown efficacy as salvage monotherapy for invasive aspergillosis (IA) in two open label non-comparative trials. The association between hepatotoxicity and concomitant use of CAS and cyclosporin A (CsA) has not been fully elucidated. We report results on CAS efficacy in the first cohort from outside Europe and USA and the interaction between CAS and CsA. We retrospectively reviewed the charts of all patients with haematological malignancies or postallogeneic haematopoietic stem cell transplant (HSCT) who received >/=1 dose of CAS as salvage monotherapy for IA as part of the Australian Special Access Scheme (4/2001-8/2002). Outcomes were assessed at the end of CAS therapy. Favourable response (FR) was defined as >50% clinical and radiological improvement. Risk factors for elevation of liver transaminases (LTs) were examined using multivariate models. 54 patients were included in the analysis with 47 neutropenic at study entry. Proven or probable IA occurred in 11 and refractory IA in 28. An FR occurred in 26 (48.1%) and predictors for a poor response to CAS were allogeneic HSCT, graft vs. host disease and treatment with CAS for <14 days. Concomitant CAS and CsA for >7 days was an independent risk factor for laboratory hepatoxicity. The CAS efficacy results from the Australian cohort confirm those of previous studies. Close monitoring of LTs is necessary on concomitant CAS and CsA but clinically relevant hepatotoxicity is rare.

Relevant imaging findings of cerebral aspergillosis on MRI: a retrospective case-based study in immunocompromised patients

The aim of the study was to assess neuroimaging patterns of cerebral aspergillosis with magnetic resonance imaging (1.5 T). The clinical and imaging data of nine patients were reviewed. Patients were included in the study if the diagnosis of aspergillosis was confirmed by either biopsy, autopsy, aspergillus antigen determination and/or neuroradiological and clinical response to specific treatment. Four patients had single or multiple abscesses presenting as ring-enhancing lesions on T1-weighted images, hypointensity of the ring on T2-weighted MR images and low to high signal intensity on diffusion-weighted imaging. Four patients had single or multiple infarctions affecting all compartments of the brain with hyperintensities on T2-weighted images in three of four patients, irregular parenchymal contrast enhancement in all patients and hemorrhagic transformation of the infarcted parenchyma in one patient. Diffusion-weighted images were positive in all ischemic areas. One patient with paranasal sinusitis developed a mycotic aneurysm of the internal carotid artery. Cerebral aspergillosis presents three principal neuroimaging findings: areas consistent with infarction; ring lesions consistent with abscess formation following infarction; and dural or vascular infiltration originating from paranasal sinusitis or orbital infiltration. Recognition of these patterns in cerebral aspergillosis may lead to more timely and effective diagnosis and treatment.

In vitro determination of phagocytosis and intracellular killing of Aspergillus species by mononuclear phagocytes

We investigated phagocytosis and intracellular killing of clinical and environmental isolates of Aspergillus spp. by human monocyte-derived macrophages (MDMs). Serial pathogens such as Aspergillus fumigatus, Aspergillus flavus and Aspergillus terreus were examined with a microbiological assay. Phagocytosis for resting conidia of Aspergillus spp. was similar for all isolates tested. During 30 min of incubation phagocytosis ranged from 49.9% to 85.5% for clinical isolates and from 40.3% to 87.1% for environmental isolates. MDMs killed A. fumigatus, A. flavus and A. terreus conidia after ingestion for 120 min, as shown by a decrease in colony forming units (cfu) count of intracellular fungi. The killing index for all isolates of Aspergillus spp., ranged from 12.1 +/- 1.1% to 90.3 +/- 10.4%; isolate-dependent (P < 0.01) differences against the fungicidal action of MDMs were observed. In conclusion, significant differences were noted for killing indices between several strains of Aspergillus spp. whereas phagocytosis was similar for all isolates tested in vitro. No differences were observed within environmental and clinical isolates.

Bronchoalveolar lavage galactomannan in diagnosis of invasive pulmonary aspergillosis among solid-organ transplant recipients

We review the experience at our institution with galactomannan (GM) testing of bronchoalveolar lavage (BAL) fluid in the diagnosis of invasive pulmonary aspergillosis (IPA) among solid-organ transplant recipients. Among 81 patients for whom BAL GM testing was ordered (heart, 24; kidney, 22; liver, 19; lung, 16), there were five cases of proven or probable IPA. All five patients had BAL GM of > or = 2.1 and survived following antifungal therapy. The sensitivity, specificity, and positive and negative predictive values for BAL GM testing at a cutoff of > or = 1.0 were 100%, 90.8%, 41.7%, and 100%, respectively. The sensitivity of BAL GM testing was better than that of conventional tests such as serum GM or BAL cytology and culture. Moreover, a positive BAL GM test diagnosed IPA several days to 4 weeks before other methods for three patients. Twelve patients had BAL GM of > or = 0.5 but no evidence of IPA. Among these, lung transplant recipients accounted for 41.7% (5/12) of the false-positive results, reflecting frequent colonization of airways in this population. Excluding lung transplants, the specificity and positive predictive value for other solid-organ transplants increased to 92.9% and 62.5%, respectively (cutoff, > or = 1.0). In conclusion, BAL GM testing facilitated more-rapid diagnoses of IPA and the institution of antifungal therapy among non-lung solid-organ transplant recipients and helped to rule out IPA.

Epidemiology of invasive candidiasis: a persistent public health problem

Invasive candidiasis (IC) is a leading cause of mycosis-associated mortality in the United States. We examined data from the National Center for Health Statistics and reviewed recent literature in order to update the epidemiology of IC. IC-associated mortality has remained stable, at approximately 0.4 deaths per 100,000 population, since 1997, while mortality associated with invasive aspergillosis has continued to decline. Candida albicans remains the predominant cause of IC, accounting for over half of all cases, but Candida glabrata has emerged as the second most common cause of IC in the United States, and several less common Candida species may be emerging, some of which can exhibit resistance to triazoles and/or amphotericin B. Crude and attributable rates of mortality due to IC remain unacceptably high and unchanged for the past 2 decades. Nonpharmacologic preventive strategies should be emphasized, including hand hygiene; appropriate use, placement, and care of central venous catheters; and prudent use of antimicrobial therapy. Given that delays in appropriate antifungal therapy are associated with increased mortality, improved use of early empirical, preemptive, and prophylactic therapies should also help reduce IC-associated mortality. Several studies have now identified important variables that can be used to predict risk of IC and to help guide preventive strategies such as antifungal prophylaxis and early empirical therapy. However, improved non-culture-based diagnostics are needed to expand the potential for preemptive (or early directed) therapy. Further research to improve diagnostic, preventive, and therapeutic strategies is necessary to reduce the considerable morbidity and mortality associated with IC.

Concentration-dependent synergy and antagonism within a triple antifungal drug combination against Aspergillus species: analysis by a new response surface model

Triple antifungal combinations are used against refractory invasive aspergillosis without an adequate understanding of their pharmacodynamic interactions. We initially studied the in vitro triple combination of voriconazole, amphotericin B, and caspofungin against Aspergillus fumigatus, A. flavus, and A. terreus by a spectrophotometric microdilution broth method after 48 h of incubation. We then analyzed these results with a recently described nonlinear mixture response surface E(max)-based model modified to assess pharmacodynamic interactions at various growth levels. The new model allows flexibility in all four parameters of the E(max) model and is able to describe complex pharmacodynamic interactions. Concentration-dependent pharmacodynamic interactions were found within the triple antifungal combination. At the 50% growth level, synergy (median interaction indices of 0.43 to 0.82) was observed at low concentrations of voriconazole (<0.03 mg/liter) and amphotericin B (</=0.20 mg/liter) and at intermediate concentrations of caspofungin (0.95 to 14.88 mg/liter), whereas antagonism (median interaction indices of 1.17 to 1.80) was found at higher concentrations of voriconazole and amphotericin B. Ternary plot and interaction surface analysis further revealed the complexity of these concentration-dependent interactions. With increasing concentrations of amphotericin B, the synergistic interactions of voriconazole-caspofungin double combination decreased while the antagonistic interactions increased. A similar effect was observed when voriconazole was added to the double combination of amphotericin B and caspofungin. In conclusion, the new nonlinear mixture-amount response surface modeling of the triple antifungal combination demonstrated a net antagonism or synergy against Aspergillus species depending upon drug concentrations and species.

Behavior of itraconazole and benzyl alcohol in aqueous solution containing nonionic surfactants

In order to investigate the behavior of itraconazole and benzyl alcohol in aqueous solution containing surfactants, the distribution of itraconazole and benzyl alcohol between the micellar and aqueous phases was determined and the partition of itraconazole between the hydrophilic and lipophilic moieties in micelles was measured. From these experiments, we can conclude that: (1) in aqueous surfactant solution, itraconazole mainly exists in the micellar phase; (2) the cosolvency effect of benzyl alcohol has a negligible effect on the solubility of itraconazole in aqueous solution; (3) itraconazole tends to align itself in an intermediate position (palisade layer) within the surfactant molecules forming the micelle, which may result in the destruction of the micellar structure; and (4) the precipitation of itraconazole may occur in the process of the exchange of benzyl alcohol between the aqueous and micellar phases. This is the mechanism of destabilization of colloidal drug carriers based on benzyl alcohol.

Galactomannan antigen enzyme-linked immunosorbent assay for diagnosis of invasive aspergillosis after hematopoietic stem cell transplantation

Invasive aspergillosis is difficult to diagnose in patients undergoing hematopoietic stem cell transplantation (HSCT). In 2003, a serum enzyme-linked immunosorbent assay (ELISA) test for the detection of galactomannan (a glycoprotein found on the Aspergillus cell wall) became available in the United States. In 2004, patients undergoing HSCT were screened biweekly with the galactomannan ELISA at our institution. We performed a retrospective chart review of 121 SCT patients who underwent galactomannan testing. Thirteen of the patients (10.7%) had at least 1 positive galactomannan ELISA, and 4 had multiple positive tests. When calculated in reference to a proved or probable diagnosis of aspergillosis, the galactomannan ELISA had a sensitivity of 0.50 and a specificity of 0.94. The positive predictive value was 0.46, and the negative predictive value was 0.94. Galactomannan ELISA had fewer false-positive and false-negative results in pediatric patients than in adult patients. In 4 of the 12 cases of invasive aspergillosis, the galactomannan ELISA was positive before other microbiologic evidence of aspergillosis was available. In these cases, a positive ELISA predated culture and cytologic evidence of invasive aspergillosis by a mean of 5 days (range, 1-8 days). Our findings indicate that a biweekly serum galactomannan ELISA is a highly specific diagnostic tool for detecting invasive aspergillosis in patients undergoing HSCT. When used regularly, the ELISA may allow for earlier diagnosis of invasive aspergillosis in some patients. The test is troubled by a low sensitivity and high frequency of false-negative tests.

Treatment of Invasive Aspergillosis with Posaconazole in Patients Who Are Refractory to or Intolerant of Conventional Therapy: An Externally Controlled Trial

BACKGROUND

Invasive aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Current treatments provide limited benefit. Posaconazole is an extended-spectrum triazole with in vitro and in vivo activity against Aspergillus species.

METHODS

We investigated the efficacy and safety of posaconazole oral suspension (800 mg/day in divided doses) as monotherapy in an open-label, multicenter study in patients with invasive aspergillosis and other mycoses who were refractory to or intolerant of conventional antifungal therapy. Data from external control cases were collected retrospectively to provide a comparative reference group.

RESULTS

Cases of aspergillosis deemed evaluable by a blinded data review committee included 107 posaconazole recipients and 86 control subjects (modified intent-to-treat population). The populations were similar and balanced with regard to prespecified demographic and disease variables. The overall success rate (i.e., the data review committee-assessed global response at the end of treatment) was 42% for posaconazole recipients and 26% for control subjects (odds ratio, 4.06; 95% confidence interval, 1.50-11.04; P=.006). The differences in response between the modified intent-to-treat treatment groups were preserved across additional, prespecified subsets, including infection site (pulmonary or disseminated), hematological malignancy, hematopoietic stem cell transplantation, baseline neutropenia, and reason for enrollment (patient was refractory to or intolerant of previous antifungal therapy). An exposure-response relationship was suggested by pharmacokinetic analyses.

CONCLUSIONS

Although the study predates extensive use of echinocandins and voriconazole, these findings demonstrate that posaconazole is an alternative to salvage therapy for patients with invasive aspergillosis who are refractory to or intolerant of previous antifungal therapy.

Imaging findings in acute invasive pulmonary aspergillosis: clinical significance of the halo sign

BACKGROUND

Computed tomography (CT) of the chest may be used to identify the halo sign, a macronodule surrounded by a perimeter of ground-glass opacity, which is an early sign of invasive pulmonary aspergillosis (IPA). This study analyzed chest CT findings at presentation from a large series of patients with IPA, to assess the prevalence of these imaging findings and to evaluate the clinical utility of the halo sign for early identification of this potentially life-threatening infection.

METHODS

Baseline chest CT imaging findings from 235 patients with IPA who participated in a previously published study were systematically analyzed. To evaluate the clinical utility of the halo sign for the early identification and treatment of IPA, we compared response to treatment and survival after 12 weeks of treatment in 143 patients who presented with a halo sign and in 79 patients with other imaging findings.

RESULTS

At presentation, most patients (94%) had > or =1 macronodules, and many (61%) also had halo signs. Other imaging findings at presentation, including consolidations (30%), infarct-shaped nodules (27%), cavitary lesions (20%), and air-crescent signs (10%), were less common. Patients presenting with a halo sign had significantly better responses to treatment (52% vs. 29%; P<.001) and greater survival to 84 days (71% vs. 53%; P<.01) than did patients who presented with other imaging findings.

CONCLUSIONS

Most patients presented with a halo sign and/or a macronodule in this large imaging study of IPA. Initiation of antifungal treatment on the basis of the identification of a halo sign by chest CT is associated with a significantly better response to treatment and improved survival.

Acute pulmonary aspergillosis in immunocompetent subjects after exposure to bark chippings

We describe 2 cases of immunocompetent males with acute community-acquired invasive pulmonary aspergillosis developing shortly after spreading bark chippings. One patient with a fatal outcome was initially diagnosed as allergic alveolitis rather than infection and received steroid treatment illustrating the obvious challenges in the differential diagnosis between these disease entities.

Issues Related to the Design and Interpretation of Clinical Trials of Salvage Therapy for Invasive Mold Infection

Invasive mold infection is a major cause of morbidity and mortality among severely immunocompromised individuals. We discuss the challenges involved in the design and interpretation of salvage antifungal trials, focusing on mold infection. We suggest that patients with refractory fungal infection be analyzed separately from those with intolerance to standard regimens because of the poorer prognosis of the former group. We propose a composite outcome assessment in which refractory infection is defined as infection associated with the worsening of at least 2 of the following 3 types of criteria: clinical, radiologic, and mycologic. Confounding variables, including heterogeneity in host factors, initial antifungal therapy, and selection bias, are discussed. Although randomized studies would provide the most credible results, the lack of an adequate number of patients to meet prespecified stratification criteria for all confounding variables makes such studies impractical. Given that randomized studies are unrealistic, studies involving carefully selected, matched, contemporaneous control subjects are likely to be the most useful alternative.

The role of echinocandins, extended-spectrum azoles, and polyenes to treat opportunistic moulds and candida

Three classes of antifungals--polyenes, extended-spectrum azoles, and echinocandins--are now available for treating systemic fungal infections. Guidance for the appropriate use of this expanded variety of antifungals may come from recent clinical trials. Extended-spectrum azoles have excellent in vitro activity against Aspergillus and have been shown to improve clinical outcomes. For Zygomycetes, along with the lipid formulations of amphotericin, of the new agents, only posaconazole has activity. For Candida, the echinocandins offer a broad spectrum of activity. These new agents offer less toxicity and potentially improved efficacy in these difficult infections.

Voriconazole brain tissue levels in rhinocerebral aspergillosis in a successfully treated young woman

Invasive aspergillosis of the central nervous system has a mortality rate exceeding 90%. We describe a 29-year-old woman with a medical history of chronic polyarthritis who developed a proven rhinocerebral Aspergillus fumigatus infection refractory to first-line treatment with liposomal amphotericin B. The patient responded successfully to salvage combination treatment with voriconazole and caspofungin. Furthermore, for the first time, voriconazole levels in an intracerebral abscess were measured in this patient undergoing voriconazole oral therapy.

Echinocandins in the management of invasive fungal infections, part 2

PURPOSE

The chemistry, pharmacology, spectrum of activity, resistance, pharmacokinetics, pharmacodynamics, clinical efficacy, adverse effects, drug interactions, dosage and administration, cost, and place in therapy of echinocandins are reviewed.

SUMMARY

Three echinocandins are currently available: caspofungin, micafungin, and anidulafungin. The principal mechanism of action of the echinocandins is the noncompetitive inhibition of beta-(1,3)-D-glucan synthase, an essential component of the cell wall of many fungi that is not present in mammalian cells. Echinocandins exhibit fungicidal activity against Candida species, including triazole-resistant isolates, and fungistatic activity against Aspergillus species. While fungistatic against mold, echinocandins may hold promise for the treatment of these pathogens when given in combination with amphotericin B or broad-spectrum triazoles, such as voriconazole. To date, resistance to echinocandins has been reported in only two patients. Echinocandins exhibit concentration-dependent activity against Candida species. In clinical trials, caspofungin has demonstrated efficacy in treating candidemia, esophageal candidiasis, and febrile neutropenia. Micafungin has demonstrated efficacy as antifungal prophylaxis in hematopoietic stem cell transplant recipients and in the treatment of esophageal candidiasis. Anidulafungin received approved labeling from the Food and Drug Administration in February 2006. Clinical efficacy data will be forthcoming.

CONCLUSION

Echinocandins are fungicidal against yeast and fungistatic against mold. Their limited toxicity profile and minimal drug-drug interactions make them an attractive new option for the treatment of invasive fungal infections. Their cost may limit their use as initial therapy for patients with fungemia in medical centers or intensive care units with a high rate of triazoleresistant Candida infections.

Interaction between posaconazole and caspofungin in concomitant treatment of mice with systemic Aspergillus infection

The interaction of posaconazole and caspofungin was evaluated in concomitant treatment of Aspergillus fumigatus (two strains) or A. flavus (one strain) systemic infections in immunocompetent mice. Survival curves for mice treated with the combinations were compared statistically with those for mice treated with the component monotherapies. No antagonism was observed.

Aspergillus brain abscess in a patient with acute myeloid leukaemia successfully treated with voriconazole

Cerebral aspergillosis is associated with very high mortality in immunocompromised hosts. Conventional antifungal agents like amphotericin-B and itraconazole are almost ineffective in cerebral aspergillosis. Newer azoles have been shown to penetrate the blood, cerebrospinal fluid barrier and achieve effective fungicidal concentrations. These newer azoles may change the outlook of this fatal condition. We report here a patient with cerebral aspergillosis who was successfully treated with voriconazole.

Invasive aspergillosis of the central nervous system after allogeneic stem cell transplantation

Central nervous system aspergillosis is a rare infectious complication in patients submitted to allogeneic stem cell transplantation. When it arises, this infection appears early post-transplant and most patients present with multiple central nervous system lesions. We report the clinical case of a 52 year old woman with IgGk multiple myeloma in relapse after a matched related allogeneic bone marrow transplant, who presented with a single large central nervous system Aspergillus lesion 11 months post-transplant in the setting of acute graft vs. host disease developing after the infusion of donor leucocytes. Although liposomal amphotericin B was promptly instituted, the patient died 1 week after the diagnosis.

Primer R108 performs best in the RAPD strain typing of three Aspergillus species frequently isolated from patients

We evaluated the suitability of various primers for the RAPD (random amplified polymorphic DNA) accurate species identification and strain typing of Aspergillus clinical isolates. Five primers described previously were tested for their discriminatory power in three Aspergillus species (A. fumigatus, A. niger agg. and A. flavus - 23 clinical isolates and 2 reference strains). Clustering of RAPD fingerprints corresponded well with the identification based on morphological features. All isolates were resolved as different strains using the primer R108 and the RAPD protocol optimized for a Robocycler thermal cycler. RAPD with the primer R108 thus can be considered to be a valuable, simple and powerful tool for identification and strain delineation of Aspergillus spp.

Design of clinical trials of empiric antifungal therapy in patients with persistent febrile neutropenia: considerations and critiques

Febrile neutropenic patients who receive antibiotics are at risk for fungal infections. This risk increases greatly with the length and severity of neutropenia. Because diagnostic tests for fungal infections lack sensitivity and specificity and because established fungal infections are associated with poor outcomes, empiric antifungal therapy is frequently given to patients with fever that persists despite antibacterial therapy. Early trials of empiric amphotericin B showed reductions in the number of invasive fungal infections and in related morbidity and mortality. However, as a result of infusion-related and renal adverse effects of amphotericin B, newer agents, such as lipid formulations of amphotericin B, extended-spectrum azoles, and echinocandins, have been developed. Although these alternatives have been associated with decreased toxicity, improved efficacy has not been clearly demonstrated. Although empiric antifungal therapy can prevent undetected breakthrough infections and morbidity associated with many fungal infections, its shortcomings include overtreatment, toxicity, and increased costs of unnecessary treatment. Recent studies have highlighted several questions in trial design and data interpretation. For example, what is the appropriate study design? Who should be enrolled in studies of empiric antifungal therapy? How should successful therapy be defined? These issues are reviewed to determine whether new antifungal agents should be evaluated for empiric use in patients with fever and neutropenia.

Fungal CNS infections in patients with hematologic malignancy

Various fungal agents can cause CNS infections. CNS fungal infections may present as a mass (i.e., brain abscess) typically in the course of aspergillosis or zygomycosis, or may primarily involve the meninges (i.e., meningitis), as can be observed in patients with candidiasis or cryptococcosis. Most commonly, fungal brain abscesses are due to aspergillosis. CNS aspergillosis is observed particularly in acute leukemia and allogeneic hemopoietic stem cell transplantation patients. Usually, aspergillosis is localized in the lungs and secondarily spreads to the brain; only in few cases does it develop as solitary localization of CNS. In these conditions, diagnosis is very difficult because signs and symptoms can be completely aspecific. Diagnosis can often be performed only through aggressive procedures (i.e., stereotactic puncture). Zygomycetes are the second most frequent cause of brain abscesses. CNS involvement is higher than in the course of invasive aspergillosis, and this fungal complication is also characterized by a high mortality rate. In vitro and in vivo studies demonstrated that only posaconazole and lipid formulations of amphotericin B present some possibility of success in the treatment of zygomycosis, but the pharmacologic approach should always be associated with surgery. Among molds, other agents (i.e., Fusarium and Scedosporium) may also be responsible for fungal abscess. More rarely during the course of a hematologic malignancy, a meningeal candidiasis or cryptococcosis may be observed. This review mainly focuses on the epidemiology, clinical manifestations, diagnosis and management strategies of all cases of CNS fungal infections in hematologic patients.

Review of Epidemiology, Diagnosis, and Treatment of Invasive Mould Infections in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Invasive mould infections are a major cause of morbidity and mortality in hematopoietic stem cell transplant recipients (HSCT). Allogeneic HSCT recipients are at substantially higher risk than autologous HSCT recipients. Although neutropenia following the conditioning regimen remains an important risk factor for opportunistic fungal infections, most cases of invasive mould infection in allogeneic HSCT recipients occur after neutrophil recovery in the setting of potent immunosuppressive therapy for graft-versus-host disease. Invasive aspergillosis is the most common mould infection. However, there has been an increased incidence of less common non-Aspergillus moulds that include zygomycetes, Fusarium sp., and Scedosporium sp. Reflecting a key need, important advances have been made in the antifungal armamentarium. Voriconazole has become a new standard of care as primary therapy for invasive aspergillosis based on superiority over amphotericin B. There is significant interest in combination therapy for invasive aspergillosis pairing voriconazole or an amphotericin B formulation with an echinocandin. There have also been advances in novel diagnostic methods that facilitate early detection of invasive fungal infections that include galactomannan and beta-glucan antigen detection and PCR using fungal specific primers. We review the epidemiology, diagnosis, and management of invasive mould infection in HSCT, with a focus on allogeneic recipients. We also discuss options for prevention and early treatment of invasive mould infections.