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

Inhibitory and fungicidal effects of antifungal drugs against Aspergillus species in the presence of serum

Given the high protein binding rates of antifungal drugs and the effect of serum proteins on Aspergillus growth, we investigated the in vitro pharmacodynamics of amphotericin B, voriconazole, and three echinocandins in the presence of human serum, assessing both inhibitory and fungicidal effects. In vitro inhibitory (IC) and fungicidal (FC) concentrations against 5 isolates of Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus were determined with a CLSI M38-A2-based microdilution method using the XTT methodology after 48 h of incubation at 35 °C with a medium supplemented with 50% human serum. In the presence of serum, the IC and FC of amphotericin B and the IC of echinocandins were increased (1.21- to 13.44-fold), whereas voriconazole IC and FC were decreased (0.22- to 0.90-fold). The amphotericin B and voriconazole FC/IC ratios did not change significantly (0.59- to 2.33-fold) in the presence of serum, indicating that the FC increase was due to the IC increase. At echinocandin concentrations above the minimum effective concentration (MEC), fungal growth was reduced by 10 to 50% in the presence of human serum, resulting in complete inhibition of growth for some isolates. Thus, the in vitro activities of amphotericin B and echinocandins were reduced, whereas that of voriconazole was enhanced, in the presence of serum. These changes could not be predicted by the percentage of protein binding, indicating that other factors and/or secondary mechanisms may account for the observed in vitro activities of antifungal drugs against Aspergillus species in the presence of serum.

Evaluation and Management of Bacterial and Fungal Infections Occurring in Patients with a Hematological Malignancy: A 2011 Update

Patients with a hematological malignancy are a heterogeneous patient population who are afflicted with diseases that range from rapidly fatal acute leukemia to indolent lymphoma or chronic leukemia. Treatment options for these patients range from observation to hematopoietic stem cell transplantation (HSCT), but all patients are more susceptible to infection. The problem of infection is dynamic with continued shifts in pathogenic organisms and microbial susceptibilities, new treatment regimens that further diminish immune function, and patients receiving treatment who are now older and frailer. The classic patterns of immunodeficiency for patients with a hematological malignancy include: periods of profound neutropenia, increased iatrogenic risks (i.e., central vascular catheters), and cellular immune suppression that affects HSCT recipients, patients with lymphoid malignancies, and those receiving treatment with corticosteroids or agents like alemtuzumab [1–4]. Recent advances in antimicrobial drug development, new technology, clinical trial results, and further clinical experience have enhanced the database on which to make infection prophylaxis and treatment decisions. However, the practicing clinician must remember that the majority of basic infection management principles for patients who are neutropenic remain unchanged.

Overview of invasive fungal infections

The incidence of invasive fungal infections (IFIs) has seen a marked increase in the last two decades. This is especially evident among transplant recipients, patients suffering from AIDS, in addition to those in receipt of immunosuppressive therapy. Worryingly, this increased incidence includes infections caused by opportunistic fungi and emerging fungal infections which are resistant to or certainly less susceptible than others to standard antifungal agents. As a direct response to this phenomenon, there has been a resolute effort over the past several decades to improve early and accurate diagnosis and provide reliable screening protocols thereby promoting the administration of appropriate antifungal therapy for fungal infections. Early diagnosis and treatment with antifungal therapy are vital if a patient is to survive an IFI. Substantial advancements have been made with regard to both the diagnosis and subsequent treatment of an IFI. In parallel, stark changes in the epidemiological profile of these IFIs have similarly occurred, often in direct response the type of antifungal agent being administered. The effects of an IFI can be far reaching, ranging from increased morbidity and mortality to increased length hospital stays and economic burden.

The index case for the fungal meningitis outbreak in the United States

Persistent neutrophilic meningitis presents a diagnostic challenge, because the differential diagnosis is broad and includes atypical infectious causes. We describe a case of persistent neutrophilic meningitis due to Aspergillus fumigatus in an immunocompetent man who had no evidence of sinopulmonary or cutaneous disease. An epidural glucocorticoid injection was identified as a potential route of entry for this organism into the central nervous system, and the case was reported to the state health department.

Voriconazole hepatotoxicity in severe liver dysfunction

There are no studies regarding to these effects in patients with severe liver dysfunction.

OBJECTIVES

The aims of this study were to characterize voriconazole hepatotoxicity in patients with severe liver dysfunction and to compare it with a matched cohort treated with liposomal amphotericin B.

METHODS

This is an observational study, in which adults patients treated with at least 4 doses of voriconazole were included. Patients treated with liposomal amphotericin B were used as control group.

RESULTS

Sixty nine percent of patients treated with voriconazole showed changes in liver function tests (LFTs) during therapy. They showed elevated transaminases in 35%, cholestasis in 15% or a combination of both in 45%. According to the CTC classification, all patients with hepatotoxicity had a severe reaction. The Roussel Uclaf Causality Assessment Method score in all patients with hepatotoxicity was greater than 8. There was a correlation between initial loading dose greater than 300 mg (4.5 mg/kg) and the risk of hepatotoxicity (p < 0.001). The control group developed alterations in the LFTs in only 10.3% of patients.

CONCLUSION

Voriconazole should be used with caution in patients with severe liver dysfunction and following liver transplantation, with frequent monitoring of LFTs or using liposomal amphotericin B instead.

(1-3)-β-D-Glucan vs Galactomannan Antigen in Diagnosing Invasive Fungal Infections (IFIs)

Invasive fungal infections (IFIs) are serious and often life-threatening complications in patients with haematological malignancies. Early diagnosis and the initiation of efficacious antifungal treatments could affect the prognosis of these patients. The detection of (1-3)-β-D-Glucan (BDG) could be a promising non-culture-based, noninvasive tool for IFI analyses in haemato-oncological patients, allowing the diagnosis of the two major IFIs, invasive aspergillosis (IA) and invasive candidiasis (IC), with a single test. The aim of this work was to evaluate and compare the use of the BDG in combination with the galactomannan antigen (GAL) assay in order to exclude or confirm suspected IFIs. Sera from 46 haemato-oncological patients (24 with proven/probable IFI and 22 without IFI symptoms) were evaluated retrospectively for the detection of GAL and BDG. In 24 patients, the serum BDG levels facilitated IFI diagnosis: 18 probable IA, 3 proven IA and 3 IC. In the remaining 22 patients, the BDG level helped exclude IFIs. The BDG was positive earlier than GAL in 5/24 cases [three of probable invasive aspergillosis (IA), one of proven IA and one case of proven invasive candidiasis (IC)] and was positive at the same time as GAL in 19/24 cases; in no case was GAL positive before BDG was. The BDG detection is useful, however, the test has a great limitation because it is a completely manual procedure.

In vitro pharmacokinetic/pharmacodynamic modeling of voriconazole activity against Aspergillus species in a new in vitro dynamic model

The pharmacodynamics (PD) of voriconazole activity against Aspergillus spp. were studied using a new in vitro dynamic model simulating voriconazole human pharmacokinetics (PK), and the PK-PD data were bridged with human drug exposure to assess the percent target (near-maximum activity) attainment of different voriconazole dosages. Three Aspergillus clinical isolates (1 A. fumigatus, 1 A. flavus, and 1 A. terreus isolate) with CLSI MICs of 0.5 mg/liter were tested in an in vitro model simulating voriconazole PK in human plasma with C(max) values of 7, 3.5, and 1.75 mg/liter and a t(1/2) of 6 h. The area under the galactomannan index-time curve (AUC(GI)) was used as the PD parameter. In vitro PK-PD data were bridged with population human PK of voriconazole exposure, and the percent target attainment was calculated. The in vitro PK-PD relationship of fAUC(0-24)-AUC(GI) followed a sigmoid pattern (global R(2) = 0.97), with near-maximum activities (10% fungal growth) observed at an fAUC(0-24) (95% confidence interval [CI]) of 18.9 (14.4 to 23.1) mg · h/liter against A. fumigatus, 26.6 (21.1 to 32.9) mg · h/liter against A. flavus, and 36.2 (27.8 to 45.7) mg · h/liter against A. terreus (F test; P < 0.0001). Target attainment for 3, 4, and 5 mg/kg-of-body-weight voriconazole dosages was 24% (11 to 45%), 80% (32 to 97%), and 93% (86 to 97%) for A. fumigatus, 12% (5 to 26%), 63% (17 to 93%), and 86% (73 to 94%) for A. flavus, and 4% (2 to 11%), 36% (6 to 83%), and 68% (47 to 83%) for A. terreus. Based on the in vitro exposure-effect relationships, a standard dosage of voriconazole may be adequate for most patients with A. fumigatus but not A. flavus and A. terreus infections, for which a higher drug exposure may be required. This could be achieved using a higher voriconazole dosage, thus highlighting the usefulness of therapeutic drug monitoring in patients receiving a standard dosage.

A MIQE-compliant real-time PCR assay for Aspergillus detection

The polymerase chain reaction (PCR) is widely used as a diagnostic tool in clinical laboratories and is particularly effective for detecting and identifying infectious agents for which routine culture and microscopy methods are inadequate. Invasive fungal disease (IFD) is a major cause of morbidity and mortality in immunosuppressed patients, and optimal diagnostic criteria are contentious. Although PCR-based methods have long been used for the diagnosis of invasive aspergillosis (IA), variable performance in clinical practice has limited their value. This shortcoming is a consequence of differing sample selection, collection and preparation protocols coupled with a lack of standardisation of the PCR itself. Furthermore, it has become clear that the performance of PCR-based assays in general is compromised by the inadequacy of experimental controls, insufficient optimisation of assay performance as well as lack of transparency in reporting experimental details. The recently published "Minimum Information for the publication of real-time Quantitative PCR Experiments" (MIQE) guidelines provide a blueprint for good PCR assay design and unambiguous reporting of experimental detail and results. We report the first real-time quantitative PCR (qPCR) assay targeting Aspergillus species that has been designed, optimised and validated in strict compliance with the MIQE guidelines. The hydrolysis probe-based assay, designed to target the 18S rRNA DNA sequence of Aspergillus species, has an efficiency of 100% (range 95-107%), a dynamic range of at least six orders of magnitude and limits of quantification and detection of 6 and 0.6 Aspergillus fumigatus genomes, respectively. It does not amplify Candida, Scedosporium, Fusarium or Rhizopus species and its clinical sensitivity is demonstrated in histological material from proven IA cases, as well as concordant PCR and galactomannan data in matched broncho-alveolar lavage and blood samples. The robustness, specificity and sensitivity of this assay make it an ideal molecular diagnostic tool for clinical use.

Murine infection models for Aspergillus terreus pulmonary aspergillosis reveal long-term persistence of conidia and liver degeneration

Aspergillus terreus is emerging as a causative agent of life-threatening invasive aspergillosis. Prognosis for affected patients is often worse than for A. fumigatus infections. To study A. terreus-mediated disease, we developed 3 infection models. In embryonated hen's eggs and leucopenic mice, the outcome of invasive aspergillosis was similar to that described for A. fumigatus. However, 10(2)- and 10(3)-fold higher conidia concentrations were required for 100% lethality. In corticosteroid-treated mice, only 50% mortality was observed, although bioluminescence imaging revealed transient disease in all infected animals. In surviving animals, we observed persistence of ungerminated but viable conidia. Cytokine levels in these mice were comparable to uninfected controls. In contrast to A. fumigatus infections, all mice infected with A. terreus developed fatty liver degeneration, suggesting the production of toxic secondary metabolites. Thus, at least in mice, persistence and subclinical liver damage are unique features of A. terreus infections.

Neonatal cutaneous disseminated aspergillosis in a preterm extremely-low-birth-weight infant with favourable outcome at 3-year follow-up: a case report

Invasive disseminated neonatal aspergillosis is an uncommon disease, with only scattered reports in literature in the last few years. Here we report on a 25-week gestational age, 730 g at birth preterm female infant who developed on day-of-life 10 multiple cutaneous exhulcerative lesions in her right arm, trunk and abdomen. Early recognition and diagnosis of these lesions as a due to cutaneous initial symptom of cutaneous disseminated aspergillosis, as well as prompt treatment with Liposomal amphotericin B + Itraconazole, secured successful recovery from the systemic infection. Skin lesions healed without any surgical treatment. The infant was discharged in good health. Long-term follow-up at three years of age revealed normality of all neurodevelopmental and cognitive parameters. To our knowledge, this is one of the very few cases of survival, free from sequelae, for a preterm infant affected by neonatal cutaneous disseminated aspergillosis.

Association between a Primitive Brain Tumor and Cerebral Aspergillosis

Cerebral aspergillosis is a rare pathology of poor prognosis in spite of the use of adapted antifungal treatments. This infection of the central nervous system is generally the complication of an invasive aspergillosis with hematogenic scattering from pulmonary focal spots. It can arise in immunocompetent patients treated with prolonged corticotherapy or chemoradiotherapy for cancer. A case of lethal cerebral aspergillosis in a patient with an infiltrative glioma treated with corticotherapy and radiotherapy is reported. Clinicopathological aspects and therapeutic approach are described.

Aspergillus osteomyelitis of the lumbar spine complicated with orbital apex syndrome: A potential role of the Batson's plexus in disease propagation

We report a rare case of orbital apex syndrome following epidural steroid injections of the lumbar spine in an immunocompetent individual with osteomyelitis and discitis caused by Aspergillus fumigatus. We suspect that the craniospinal venous system, also known as the Batson's plexus, was the main route for steroid-facilitated disease propagation from the spine to intracranial structures.

Invasive fungal infection among hematopoietic stem cell transplantation patients with mechanical ventilation in the intensive care unit

Background

Invasive fungal infection (IFI) is associated with high morbidity and high mortality in hematopoietic stem cell transplantation (HSCT) patientsThe purpose of this study was to assess the characteristics and outcomes of HSCT patients with IFIs who are undergoing MV at a single institution in Taiwan.

Methods

We performed an observational retrospective analysis of IFIs in HSCT patients undergoing mechanical ventilation (MV) in an intensive care unit (ICU) from the year 2000 to 2009. The characteristics of these HSCT patients and risk factors related to IFIs were evaluated. The status of discharge, length of ICU stay, date of death and cause of death were also recorded.

Results

There were 326 HSCT patients at the Linkou Chang-Gung Memorial Hospital (Taipei, Taiwan) during the study period. Sixty of these patients (18%) were transferred to the ICU and placed on mechanical ventilators. A total of 20 of these 60 patients (33%) had IFIs. Multivariate analysis indicated that independent risk factors for IFI were admission to an ICU more than 40 days after HSCT, graft versus host disease (GVHD), and high dose corticosteroid (p < 0.01 for all). The overall ICU mortality rate was 88% (53 of 60 patients), and was not significantly different for patients with IFIs (85%) and those without IFIs (90%, p = 0.676).

Conclusion

There was a high incidence of IFIs in HSCT patients requiring MV in the ICU in our study cohort. The independent risk factors for IFI are ICU admission more than 40 days after HSCT, GVHD, and use of high-dose corticosteroid.

Diagnostic value of routine chest radiography in febrile, neutropenic children for early detection of pneumonia and mould infections

BACKGROUND

Despite recent studies failing to demonstrate the value of routine chest radiography (CXR) in the initial evaluation of the febrile neutropenic patient with cancer, this screening test is advocated by some experts. We evaluated the benefits of CXR for early diagnosis of pulmonary infection at St. Jude Children's Research Hospital (SJCRH) with emphasis on early recognition of mould infections.

PATIENTS AND METHODS

We reviewed the courses of 200 consecutive febrile neutropenic pediatric patients to determine if routine CXR at initial evaluation was useful in the identification of clinically occult pneumonia. We also reviewed all cases of proven or probable mould infections from the opening of SJCRH in 1962 until 1998 when routine CXR was no longer practiced in our institution to identify cases that were first recognized by routine CXR.

RESULTS

Of 200 febrile neutropenic patients, pulmonary abnormalities consistent with pneumonia were detected by routine CXR in only five patients without pulmonary signs or symptoms. In only one case was a change in management considered. Of the 70 patients with pulmonary mould infection identified from 1962 to 1998, routine CXR was performed in 45 patients at the onset of a febrile, neutropenic episode in which a mould infection was diagnosed. Routine CXR was pivotal in the recognition of the mould infection in only two cases over this 36-year period.

CONCLUSION

CXR is warranted in the evaluation of the newly febrile neutropenic pediatric oncology patient only when respiratory signs or symptoms are present.

Assessment of Aspergillus fumigatus in guinea pig bronchoalveolar lavages and pulmonary tissue by culture and realtime polymerase chain reaction studies

In this study we pursued a diagnostic target in Aspergillus fumigatus (AF) by using qualitative Realtime PCR combined with proprietary DNA primers and a hydrolysis probe specific for this fungal target. Qualitative Realtime PCR is a diagnostic tool that utilizes Realtime PCR technology and detects the presence or absence target specific DNA within a predetermined detection range. Respiratory tissue and fluids from experimentally infected guinea pigs were tested by extracting DNA from the samples which were amplified and detected using AF specific DNA primers and probe. This study included qualitative evaluations of all specimens for the presence of the DNA of AF. The findings in the tissues after AF infection were compared to the numbers of spores in aerosolized samples used to inoculate the animals. Results demonstrated that the specific probe and primer set could detect the presence or absence of AF DNA in the sample. The qualitative detection limit of the assay ranged from 6 × 10⁴ copies to 6 copies. Since blood cultures are rarely positive for Aspergillosis, our data indicate that qualitative Realtime PCR, in combination with the appropriate DNA primers and probe can serve as an effective diagnostic tool in the early detection of fungal infections.

Invasive Fungal Sinusitis

Invasive sinus Aspergillus infection has been reported in the last decade with increased frequency, most commonly in the setting of hematologic malignancy, neutropenia, HIV infection and other states of immunosuppression. Fungal rhinosinusitis can be broadly classified into two varieties-invasive and noninvasive on the basis of tissue invasion. Invasive fungal sinusitis are acute invasive, chronic invasive (both granulomatous and nongranulomatous forms), whereas noninvasive are fungus balls and allergic fungal sinusitis. Invasive fungal sinusitis is one of the most challenging forms of sinonasal pathology to manage, most commonly presenting in immunocompromised individuals. Chronic invasive being sinus aspergillosis (CISA) is being reported in immunocompetent patients at an increasing rate while most of these cases are being reported from the India subcontinent and middle east. Invasive fungal sinusitis is on the rise worldwide and especially in north India as it is endemic in this part of the country. It is affecting immunocompetent young and middle aged population causing a great morbidity and mortality. This entity needs to be picked up early by spreading awareness among the family physicians, internists, otolaryngologists, ophthalmologists, neurosurgeons, pulmonary physicians, critical care specialists so that an early management can initiated to achieve better control over the disease. This review is an attempt to initiate an interdisciplinary approach to achieve a better outcome.

How to cite this article

Gupta AK, Bansal S, Rijuneeta, Gupta B. Invasive Fungal Sinusitis. Clin Rhinol An Int J 2012;5(2): 63-71.

A nonlethal murine cutaneous model of invasive aspergillosis

Cutaneous models allow researchers to dynamically monitor infection by visually determining changes in skin lesion dimensions over time. We present a nonlethal cutaneous model of invasive aspergillosis (IA) in nude BALB/c mice and describe its use to determine altered virulence in Aspergillus strains and response to antifungal drugs. In addition, as an example of the versatility of this model, we show how the cutaneous model can be used to assess the effect of IA on angiogenesis in vivo.

Surface display of Gaussia princeps luciferase allows sensitive fungal pathogen detection during cutaneous aspergillosis

Non-invasive imaging techniques in microbial disease models have delivered valuable insights in the intimate pathogen-host interplay during infection. Here we describe evaluation and validation of a transgenic bioluminescence reporter strain of the human-pathogenic mold Aspergillus fumigatus, one of the main fungal pathogens affecting immunocompromised individuals. Expression and surface display of the Gaussia princeps luciferase allowed sensitive and rapid detection of luminescence emitted from this strain after substrate addition, with photon fluxes strongly correlating to the amounts of fungal conidia or germlings. The reporter strain allowed spatio-temporal monitoring of infection in a cutaneous model of aspergillosis, where neutropenic mice maintained the fungal burden while immunocompetent ones were able to clear it entirely. Most importantly, antifungal therapy could be followed in this type of disease model making use of the bioluminescent A. fumigatus strain. In conclusion, combining sensitivity of the Gaussia luciferase with a surface display expression system in the fungal host allows longitudinal infection studies on cutaneous forms of aspergillosis, providing perspective on drug screening approaches at high-throughput.

Tracheobronchial manifestations of Aspergillus infections

Human lungs are constantly exposed to a large number of Aspergillus spores which are present in ambient air. These spores are usually harmless to immunocompetent subjects but can produce a symptomatic disease in patients with impaired antifungal defense. In a small percentage of patients, the trachea and bronchi may be the main or even the sole site of Aspergillus infection. The clinical entities that may develop in tracheobronchial location include saprophytic, allergic and invasive diseases. Although this review is focused on invasive Aspergillus tracheobronchial infections, some aspects of allergic and saprophytic tracheobronchial diseases are also discussed in order to present the whole spectrum of tracheobronchial aspergillosis. To be consistent with clinical practice, an approach basing on specific conditions predisposing to invasive Aspergillus tracheobronchial infections is used to present the differences in the clinical course and prognosis of these infections. Thus, invasive or potentially invasive Aspergillus airway diseases are discussed separately in three groups of patients: (1) lung transplant recipients, (2) highly immunocompromised patients with hematologic malignancies and/or patients undergoing hematopoietic stem cell transplantation, and (3) the remaining, less severely immunocompromised patients or even immunocompetent subjects.

Pharmacodynamic effects of simulated standard doses of antifungal drugs against Aspergillus species in a new in vitro pharmacokinetic/pharmacodynamic model

In conventional ΜΙC tests, fungi are exposed to constant drug concentrations, whereas in vivo, fungi are exposed to changing drug concentrations. Therefore, we developed a new in vitro pharmacokinetic/pharmacodynamic model where human plasma pharmacokinetics of standard doses of 1 mg/kg amphotericin B, 4 mg/kg voriconazole, and 1 mg/kg caspofungin were simulated and their pharmacodynamic characteristics were determined against three clinical isolates of Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus with identical MICs (1 mg/liter for amphotericin B, 0.5 mg/liter for voriconazole) and minimum effective concentrations (0.5 mg/liter for caspofungin). This new model consists of an internal compartment (a 10-ml dialysis tube made out of a semipermeable cellulose membrane allowing the free diffusion of antifungals but not galactomannan) inoculated with Aspergillus conidia and placed inside an external compartment (a 700-ml glass beaker) whose content is diluted after the addition of antifungal drugs by a peristaltic pump at the same rate as the clearance of the antifungal drugs in human plasma. Fungal growth was assessed by galactomannan production. Despite demonstrating the same MICs, amphotericin B completely inhibited (100%) A. fumigatus but not A. flavus and A. terreus, whose growth was delayed for 7.53 and 22.8 h, respectively. Voriconazole partially inhibited A. fumigatus (49.5%) and Α. flavus (27.9%) but not Α. terreus; it delayed their growth by 3.99 h (A. fumigatus) and 5.37 h (Α. terreus). Caspofungin did not alter galactomannan production in all of the species but A. terreus. The new model simulated human pharmacokinetics of antifungal drugs and revealed important pharmacodynamic differences in their activity.

Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease: a case control study from China

Patients with severe chronic obstructive pulmonary disease (COPD) are at higher risk of developing invasive pulmonary aspergillosis (IPA). However, there are limited data for this disease. To evaluate risk factors and the clinical characteristics of IPA in COPD patients, we conducted a hospital-based, retrospective case-control study of 30 COPD patients with IPA and 60 COPD control patients without IPA. Patients in the case group were significantly more likely to have concurrent co-morbidities than controls. Of the IPA patients, 65.4% had worsening radiological findings vs. 11.4% in the control group (p<0.001). IPA in COPD was associated with a higher proportion of mechanical ventilation (43.3% vs. 5%; p<0.001), a longer hospital stay duration (45.8±39.1 days vs. 18.4±11.8 days; p<0.001), and higher mortality (43.3% vs. 11.4%; p<0.001). Systemic use of steroids in the stable phase, treatment with three or more antibiotics during hospitalization and antibiotic treatment longer than 10 days were independent risk factors associated with IPA. COPD patients with obvious dyspnoea, antibiotic-resistant lower respiratory tract infection and repeated detection of Aspergillus in sputum should be considered for the possibility of IPA.

Neutrophils produce interleukin 17A (IL-17A) in a dectin-1- and IL-23-dependent manner during invasive fungal infection

We have previously reported that compromised interleukin 17A (IL-17A) production in the lungs increased susceptibility to infection with the invasive fungal pathogen Aspergillus fumigatus. Here we have shown that culturing lung cells from A. fumigatus-challenged mice ex vivo demonstrated Dectin-1-dependent IL-17A production. In this system, neutralization of IL-23 but not IL-6, IL-1β, or IL-18 resulted in attenuated IL-17A production. Il23 mRNA expression was found to be lower in lung cells from A. fumigatus-challenged Dectin-1-deficient mice, whereas bone marrow-derived dendritic cells from Dectin-1-deficient mice failed to produce IL-23 in response to A. fumigatus in vitro. Addition of recombinant IL-23 augmented IL-17A production by wild-type (WT) and Dectin-1-deficient lung cells, although the addition of IL-6 or IL-1β did not augment the effect of IL-23. Intracellular cytokine staining of lung cells revealed lower levels of CD11b(+) IL-17A(+) and Ly-6G(+) IL-17A(+) cells in A. fumigatus-challenged Dectin-1-deficient mice. Ly-6G(+) neutrophils purified from the lungs of A. fumigatus-challenged Dectin-1-deficient mice displayed lower Il17a mRNA expression but surprisingly had intact Rorc and Rora mRNA expression. We further demonstrated that Ly-6G(+) neutrophils required the presence of myeloid cells for IL-17A production. Finally, upon in vitro stimulation with A. fumigatus, thioglycolate-elicited peritoneal neutrophils were positive for intracellular IL-17A expression and produced IL-17A in a Dectin-1- and IL-23-dependent manner. In summary, Dectin-1-dependent IL-17A production in the lungs during invasive fungal infection is mediated in part by CD11b(+) Ly-6G(+) neutrophils in an IL-23-dependent manner.

Recent advances in invasive pulmonary aspergillosis

PURPOSE OF REVIEW

This review highlights the most important and salient recent developments with regards to invasive pulmonary aspergillosis (IPA), currently the most common opportunistic fungal pneumonia in patients with hematological malignancies.

RECENT FINDINGS

Besides patients in hematology units, other immunosuppressed and critically ill patients are also at risk of IPA. Identification of patients who possess specific polymorphisms of Toll-like receptor 4 and dectin-1, both of which are involved in the immune sensing of Aspergillus spp., may facilitate risk-stratification. The use of the galactomannan assay in bronchoalveolar fluid to improve diagnosis of IPA is undergoing validation. Trending galactomannan and other biomarker results may prognosticate clinical outcomes. During intensive chemotherapy for leukemia, posaconazole and aerosolized liposomal amphotericin B (L-AMB) have demonstrated efficacy as prophylaxis against invasive fungal infection. However, fluconazole remains an effective prophylactic agent in the setting of hematopoietic stem cell transplantation despite availability of newer antifungal agents. Although voriconazole is still the drug of choice for IPA, both caspofungin and L-AMB are viable alternatives.

SUMMARY

Despite increasing knowledge of IPA and availability of newer antifungal agents, clinical management remains a challenge in the setting of a compromised host defense system that is unable to mount an appropriate immune response against the pathogen.

Epidemiological trends in invasive aspergillosis in France: the SAIF network (2005-2007)

A prospective (2005-2007) hospital-based multicentre surveillance of EORTC/MSG-proven or probable invasive aspergillosis (IA) cases whatever the underlying diseases was implemented in 12 French academic hospitals. Admissions per hospital and transplantation procedures were obtained. Cox regression models were used to determine risk factors associated with the 12-week overall mortality. With 424 case-patients included, the median incidence/hospital was 0.271/10(3) admissions (range 0.072-0.910) without significant alteration of incidence and seasonality over time. Among the 393 adults (62% men, 56 years (16-84 years)), 15% had proven IA, 78% haematological conditions, and 92.9% had lung involvement. Acute leukaemia (34.6%) and allogeneic stem cell transplantation (21.4%) were major host factors, together with chronic lymphoproliferative disorders (21.6%), which emerged as a new high-risk group. The other risk host factors consisted of solid organ transplantation (8.7%), solid tumours (4.3%), systemic inflammatory diseases (4.6%) and chronic respiratory diseases (2.3%). Serum galactomannan tests were more often positive (≥69%) for acute leukaemia and allogeneic stem cell transplantation than for the others (<42%; p <10(-3)). When positive (n = 245), cultures mainly yielded Aspergillus fumigatus (79.7%). First-line antifungal therapy consisted of voriconazole, caspofungin, lipid formulations of amphotericin, or any combination therapy (52%, 14%, 8% and 19.9%, respectively). Twelve-week overall mortality was 44.8% (95% CI, 39.8-50.0); it was 41% when first-line therapy included voriconazole and 60% otherwise (p <0.001). Independent factors for 12-week mortality were older age, positivity for both culture and galactomannan and central nervous system or pleural involvement, while any strategy containing voriconazole was protective.

Immune response to Aspergillus fumigatus in compromised hosts: from bedside to bench

The relevance of studies aimed at understanding host immune response against Aspergillus fumigatus takes on much significance given that all patients with invasive aspergillosis are invariably immunocompromised. This article attempts to correlate relevant findings from recent experimental studies to clinical observations made by the physician at the bedside. It is hoped that the increased understanding of host-fungus immune interaction may pave the way for the development of new management strategies against this difficult-to-treat fungal disease.

Antifungal treatment strategies in patients with haematological diseases or cancer: from prophylaxis to empirical, pre-emptive and targeted therapy

Immunocompromised patients have a high risk for invasive fungal diseases (IFDs). These infections are mostly life-threatening and an early diagnosis and initiation of appropriate antifungal therapy are essential for the clinical outcome. Empirical treatment is regarded as the standard of care for granulocytopenic patients who remain febrile despite broad-spectrum antibiotics. However, this strategy can bear a risk of overtreatment and subsequently induce toxicities and unnecessary treatment costs. Pre-emptive antifungal therapy is now increasingly used to close the time gap between delayed initiation for proven disease and empirical treatment for anticipated infection without further laboratory or radiological evidence of fungal disease. Currently, some new non-invasive microbiological and laboratory methods, like the Aspergillus-galactomannan sandwich-enzyme immunoassay (Aspergillus GM-ELISA), 1,3-β-D-glucan assay or PCR techniques have been developed for a better diagnosis and determination of target patients. The current diagnostic approaches to fungal infections and the role of the revised definitions for invasive fungal infections, now IFDs, will be discussed in this review as well as old and emerging approaches to empirical, pre-emptive and targeted antifungal therapies in patients with haemato-oncological malignancies.

Case-control study of statin prevention of mould infections

Invasive mould infections (IMI) are associated with significant morbidity and mortality. In vitro studies have demonstrated that hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors (statins) have activity against several pathogenic moulds including Zygomycetes and Aspergillus spp. The aim of our study was to determine if statin use is a preventive factor for the development of IMI. This was a retrospective case-control study of 10 United States Veterans Affairs Medical Centers that comprise the Veterans Integrated Service Network (VISN) 16. Cases with IMI and controls were identified from 2001 to 2008. Controls were matched by age, facility, history of transplantation, presence of chronic steroid use and presence of human immunodeficiency virus infection (HIV). Two hundred and thirty-eight patients were included. Independent variables associated with the development of IMI were history of solid malignant tumours (OR 2.63, 1.41-4.87) and hypertension (OR 2.29, 1.13-4.68). Statin use within 3 months of index date was not an independent variable for prevention or development of IMI. No level of exposure to a statin drug appeared to influence the development of infection. This retrospective case-control study suggests that despite evidence of in vitro activity, statins may not decrease risk of IMI. Prospective, controlled trials may be necessary to investigate any potential clinical benefit.

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

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

An official American Thoracic Society statement: Treatment of fungal infections in adult pulmonary and critical care patients

With increasing numbers of immune-compromised patients with malignancy, hematologic disease, and HIV, as well as those receiving immunosupressive drug regimens for the management of organ transplantation or autoimmune inflammatory conditions, the incidence of fungal infections has dramatically increased over recent years. Definitive diagnosis of pulmonary fungal infections has also been substantially assisted by the development of newer diagnostic methods and techniques, including the use of antigen detection, polymerase chain reaction, serologies, computed tomography and positron emission tomography scans, bronchoscopy, mediastinoscopy, and video-assisted thorascopic biopsy. At the same time, the introduction of new treatment modalities has significantly broadened options available to physicians who treat these conditions. While traditionally antifungal therapy was limited to the use of amphotericin B, flucytosine, and a handful of clinically available azole agents, current pharmacologic treatment options include potent new azole compounds with extended antifungal activity, lipid forms of amphotericin B, and newer antifungal drugs, including the echinocandins. In view of the changing treatment of pulmonary fungal infections, the American Thoracic Society convened a working group of experts in fungal infections to develop a concise clinical statement of current therapeutic options for those fungal infections of particular relevance to pulmonary and critical care practice. This document focuses on three primary areas of concern: the endemic mycoses, including histoplasmosis, sporotrichosis, blastomycosis, and coccidioidomycosis; fungal infections of special concern for immune-compromised and critically ill patients, including cryptococcosis, aspergillosis, candidiasis, and Pneumocystis pneumonia; and rare and emerging fungal infections.

Antifungal prophylaxis and therapy in patients with hematological malignancies and hematopoietic stem cell transplant recipients

Patients with acute leukemia and hematopoietic stem cell transplant recipients are at risk of a spectrum of invasive fungal diseases corresponding to the type and intensity of immunosuppression. The development of newer antifungal agents has broadened therapeutic options. In the 1990s, lipid formulations of amphotericin B became widely used as safer alternatives to amphotericin B deoxycholate. In addition, fluconazole was shown to be beneficial as a yeast-active prophylaxis in hematopoietic stem cell transplant recipients. In the past decade, the antifungal armamentarium was further enhanced with the availability of extended-spectrum azoles and echinocandins. The development of effective broad-spectrum antifungal agents has led to their use as prophylaxis rather than delaying treatment until clinical signs of infection manifest. Antigen-based and PCR-based diagnostic adjuncts facilitate earlier detection of invasive fungal diseases compared with conventional culture, and have been incorporated into strategies in which initiation or modification of an antifungal regimen is targeted to patients with the highest likelihood of having fungal disease. Here, we review the pharmacological data and major clinical trials that guide the use of antifungals, as well as areas of uncertainty and future perspectives.

Diagnostic significance of Aspergillus species isolated from respiratory samples in an adult pneumology ward

Although the diagnostic significance of isolating Aspergillus spp. from respiratory cultures has been studied in immunocompromised hosts with invasive pulmonary aspergillosis (IPA), little is known of such infections in immunocompetent patients with other forms of aspergillosis. In this study of adult pneumology ward patients, we examined the association between Aspergillus spp. and disease prevalence. Laboratory records from April 1998 to March 2009 were reviewed to identify patients with Aspergillus spp. in respiratory samples. Correlations between the isolated species and clinical characteristics of patients were evaluated. During the study period, 165 Aspergillus spp. isolates were detected in the respiratory cultures of 139 patients. Of these patients, 62 (45%) were colonized with Aspergillus spp. and displayed no clinical symptoms of aspergillosis, while 77 (55%) had a form of pulmonary aspergillosis, characterized as either chronic necrotizing pulmonary aspergillosis (CNPA) (48%), aspergilloma (29%), IPA (13%), or allergic bronchopulmonary aspergillosis (ABPA) (10%). The dominant species were Aspergillus fumigatus (41%), A. niger (32%), and A. versicolor (12%). A. fumigatus was most commonly isolated in patients with IPA, aspergilloma, and CNPA, whereas A. niger was the dominant species in colonized patients and those with ABPA. Isolation of an Aspergillus spp. from respiratory samples does not confirm it as the etiologic pathogen because airway colonization by Aspergillus spp. is a common feature in several chronic lung diseases. Repeated isolation of the identical Aspergillus species and detection of anti-Aspergillus antibodies and/or Aspergillus antigens in sera are needed to determine the isolate represents the etiologic agent of disease.