Pulmonary aspergillosis and invasive disease in AIDS: review of 342 cases

A contemporary investigation of burden and natural history of aspergillosis in people living with HIV/AIDS

BACKGROUND

Untreated HIV infection can lead to profound immunosuppression and increase susceptibility of people living with HIV/AIDS (PLHA) to aspergillosis.

OBJECTIVES

Reporting the burden and natural history of aspergillosis documented in PLHA admitted in five medical centres in Brazil.

PATIENTS AND METHODS

Clinical, epidemiological and laboratory data were collected in all sequential cases of proven or probable aspergillosis documented in PLHA hospitalised in five medical centres between 2012 and 2020.

RESULTS

We enrolled 25 patients ageing between 23 and 58 years (mean = 39) including 11 patients with invasive aspergillosis (IA) and 14 with chronic pulmonary aspergillosis (CPA). The prevalence rate of aspergillosis was 0.1% of 19.616 PLHA. Overall, 72.7% of patients with IA exhibited CD4 < 100 cells/mL and 42.8% of patients with CPA exhibited CD4 count >200 cells/mL. Most patients had a history of tuberculosis, especially those with CPA (85.7%). IA was documented after a mean of 16.5 days of hospitalisation, mainly in critically ill patients exposed to corticosteroids and broad-spectrum antibiotics. In the CPA group, a positive culture (71.4%) and radiological alterations were the most frequent findings supporting their diagnosis. Episodes of IA were mostly documented by tissue biopsies. Crude mortality rates were 72.7% and 42.8% in patients with IA and CPA, respectively.

CONCLUSIONS

Despite being considered an unusual complication in PLHA (0.1%), IA should be considered in patients with profound immunosuppression and pneumonia refractory to conventional therapy. CPA should be investigated in PLHA with chronic deterioration of pulmonary function and previous diagnosis of tuberculosis.

Non-Aspergillus Hyaline Molds: A Host-Based Perspective of Emerging Pathogenic Fungi Causing Sinopulmonary Diseases

The incidence of invasive sino-pulmonary diseases due to non-Aspergillus hyaline molds is increasing due to an enlarging and evolving population of immunosuppressed hosts as well as improvements in the capabilities of molecular-based diagnostics. Herein, we review the following opportunistic pathogens known to cause sinopulmonary disease, the most common manifestation of hyalohyphomycosis: Fusarium spp., Scedosporium spp., Lomentospora prolificans, Scopulariopsis spp., Trichoderma spp., Acremonium spp., Paecilomyces variotii, Purpureocillium lilacinum, Rasamsonia argillacea species complex, Arthrographis kalrae, and Penicillium species. To facilitate an understanding of the epidemiology and clinical features of sino-pulmonary hyalohyphomycoses in the context of host immune impairment, we utilized a host-based approach encompassing the following underlying conditions: neutropenia, hematologic malignancy, hematopoietic and solid organ transplantation, chronic granulomatous disease, acquired immunodeficiency syndrome, cystic fibrosis, and healthy individuals who sustain burns, trauma, or iatrogenic exposures. We further summarize the pre-clinical and clinical data informing antifungal management for each pathogen and consider the role of adjunctive surgery and/or immunomodulatory treatments to optimize patient outcome.

Invasive Pulmonary Aspergillosis

Invasive pulmonary aspergillosis is growing in incidence, as patients at risk are growing in diversity. Outside the classical context of neutropenia, new risk factors are emerging or newly identified, such as new anticancer drugs, viral pneumonias and hepatic dysfunctions. Clinical signs remain unspecific in these populations and the diagnostic work-up has considerably expanded. Computed tomography is key to assess the pulmonary lesions of aspergillosis, whose various features must be acknowledged. Positron-emission tomography can bring additional information for diagnosis and follow-up. The mycological argument for diagnosis is rarely fully conclusive, as biopsy from a sterile site is challenging in most clinical contexts. In patients with a risk and suggestive radiological findings, probable invasive aspergillosis is diagnosed through blood and bronchoalveolar lavage fluid samples by detecting galactomannan or DNA, or by direct microscopy and culture for the latter. Diagnosis is considered possible with mold infection in lack of mycological criterion. Nevertheless, the therapeutic decision should not be hindered by these research-oriented categories, that have been completed by better adapted ones in specific settings. Survival has been improved over the past decades with the development of relevant antifungals, including lipid formulations of amphotericin B and new azoles. New antifungals, including first-in-class molecules, are awaited.

Quantifying Deaths from Aspergillosis in HIV Positive People

Aspergillus spp. are ubiquitous and cause severe infections in immunocompromised patients. Less is known about its incidence and prognosis in patients with HIV/AIDS. We reviewed the mortality of invasive aspergillosis in HIV/AIDS patients. Pubmed, Embase and Medline databases were used to search for articles. Studies were excluded if they contained other aspergillosis risk factors, no original or patient survival data or were not in English. From 747 articles published, 54 studies and case reports were identified following reading, published between 1985 and 2021, with 54% papers prior to 2000 reporting 853 patients from 16 countries, none from Africa. 707 (83%) patients died with an average time from diagnosis to death of 77.5 days. Postmortem diagnosis was seen in 21% of deaths recorded. A national series from France of 242 cases of invasive aspergillosis diagnosed in life recorded a 3 month mortality of 68% pre-ART, falling to 31% after introduction of ART and voriconazole. CD4 count was recorded in 39 studies and ranged from 2 to >1000 cells/mm3; only 8 patients (1.8%) had a CD4 > 100 cells/mm3. Aspergillosis occurs in patients with HIV/AIDS and associated with high mortality but its slow progression should allow diagnosis and treatment with improved outcome.

Cytopathological analysis of bronchoalveolar lavage fluid in patients with and without HIV infection

BACKGROUND

Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) infection can lead to a broad spectrum of lung diseases, including infectious diseases and tumors. Recently, with the wide application of bronchoscopes and cytopathology of bronchoalveolar lavage fluid (BALF), the diagnostic efficiency of lung diseases has improved. The present study focuses on analyzing the cytopathologic characteristics of BALF in the diagnosis of HIV/AIDS-related lung disease and comparing the lung disease spectrum between HIV and HIV-uninfected patients.

METHODS

BALF specimens were collected from 2211 patients. Using ThinPrep liquid-based technology, the cytologic smears were prepared by staining with Hematoxylin and Eosin (HE), Gomori's methenamine silver (GMS), and Periodic Acid Schiff (PAS), acid-fast and immunocytochemical (ICC) staining. Real-time PCR was used to detect cytomegalovirus (CMV) and Mycobacterium tuberculosis (M. tuberculosis) in the remaining BALF. PCR-reverse dot hybridization was used for mycobacterial species identification.

RESULTS

From the 2211 BALF specimens, 1768 (79.96%) were specimens from HIV-infected patients, and 443 (20.04%) were speciments from HIV-uninfected patients. The HIV-infected patients with a median age of 38.5 ± 11.3 years were markedly younger than the HIV-uninfected patients (52.9 ± 14.9 years) (p < 0.01). We found that 1635 (92.5%) HIV-infected patients were males, showing a prominently higher proportion than those without HIV infection (71.1%) (p < 0.01). Meanwhile, 1045 specific lesions were found in 1768 HIV-infected patients (59.1%), including 1034 cases of infectious diseases and 11 neoplastic lesions, also exhibiting a distinctly higher proportion compared to the HIV-uninfected patients (12.2%) (p < 0.001). For the HIV-infected group, a distinctly higher proportion of single infection lesions (724/1768, 41%) was noted than the HIV-uninfected group (14/443, 3.2%) (p < 0.001). Among single infection lesions, the most common was Cytomegalovirus(CMV) infection (20.9%) for the HIV-infected group, followed by Pneumocystis jiroveci(PJ) (13.0%), Fungal (3.5%), and Mycobacterial infections (3.4%), of which M. tuberculosis infection accounted for 3.1%. Double infections (300/1768, 17.0%) and Triple infections (10/1768, 0.6%) were found only among the patients with HIV. The malignancies among HIV-infected patients included adenocarcinomas (0.22%), small cell carcinomas (0.2%), squamous cell carcinomas (0.1%), and diffuse large B-cell lymphoma (0.1%). HIV-infected patients exhibited a significantly lower incidence of neoplastic lesions (0.6% vs. 9.0%) than the HIV-uninfected patients (p < 0.001).

CONCLUSIONS

There was a significant difference in the spectrum of lung diseases between HIV-infected and non-infected patients diagnosed by BALF cytopathology.

Surgical Outcome of Chronic Pulmonary Aspergilloma: An Experience from Two Tertiary Referral Hospitals in Addis Ababa, Ethiopia

BACKGROUND

Surgical management of pulmonary aspergillosis is challenging and controversial. This study is designed to assess the clinical profile, indications and surgical outcome of Pulmonary aspergilloma.

METHODS

A retrospective cross-sectional analysis of 72 patients who underwent pulmonary resection for pulmonary aspergilloma over the period from November, 2014, to November, 2019 was done. Data on demographic, clinical and surgical out come were retrieved. Analysis was done using SPSS version 23. Chi-square test was used to assess for significance of the association between variables and surgical outcome.

RESULTS

There were 46(63.9%) males and 26(36.1%) female patients with a mean age of 35.2+/-11.6 years (Range 16- 65 years). All patients were previously treated for tuberculosis. Cough, hemoptysis, and shortness of breath were the main symptoms identified. A ball of fungus together with the surrounding lung was removed. Accordingly, 32(44,4%) lobectomies, 12(16.7%) pneumonectomy, 7(9.7%) Bi-lobectomy, and 21(29.2%) cavernostomy were done. Intraoperative and Postoperative complications were seen in 8(11.1%) and 21(29.1%) patients respectively. Major morbidity encounters included massive intraoperative blood loss, prolonged air leak, empyema, air space, bronchopleural fistula, and wound infection. The hospital mortality was 3(4.2%) and the average hospital stay was 14.8days. Postoperative complications were evaluated for the difference in socio-demographic characteristics and other variables and a statistically significant difference was detected only for the location of aspergilloma, site of the lung involved and type of surgery done. (P-value =0.05.).

CONCLUSION

Pulmonary resection done for pulmonary aspergilloma showed favorable outcomes when done with good patient selection, meticulous surgical techniques, and good postoperative management. However, its long term outcome and role of antifungal treatment as adjunctive therapy for surgical resection need further investigation.

Invasive aspergillosis in patients with systemic lupus erythematosus: a retrospective study on clinical characteristics and risk factors for mortality

Objective

The objective of this paper is to analyze the clinical features, outcomes, mortality risk factors, and all-cause mortalities of invasive aspergillosis (IA) in patients with systemic lupus erythematosus (SLE).

Methods

Medical records were reviewed to identify SLE patients with IA from January 2006 to June 2017, at Taipei Veterans General Hospital, Taiwan. A total of 6714 SLE patients were included. Clinical/laboratory parameters and treatment outcomes were analyzed.

Results

Four patients (19.0%) had definite and 17 had probable (81.0%) IA. Seven patients (33.3%) survived and 14 died (66.7%). Concurrently, there were 19 pneumonias (90.5%), 17 cases of other infections (81.0%), eight bacteremia (38.1%), nine cytomegalovirus (CMV, 42.7%) and six Candida (28.6%) infections. In all 55 blood cultures, 38 (69.1%) yielded gram-negative bacilli, of which carbapenem-resistant A. baumannii accounted for eight (21.1%); 17 (30.9%) yielded gram-positive cocci, of which methicillin-resistant S. aureus accounted for six (35.3%); and vancomycin-resistant Enterococcus accounted for four (23.5%). Daily steroid dose ≥ 20 mg (hazard ratio (HR) 2.00), recent pulse steroid therapy (HR 2.80), azathioprine (HR 2.00), rituximab (HR 2.00), plasmapheresis (HR 2.00), acute respiratory distress syndrome (HR 2.00), concurrent infections (HR 5.667) and CMV viremia (HR 1.75) were higher in the fatality group. All p values were less than 0.05. Septic shock ( n = 7, 50% in the fatality group) is the most common cause of mortality.

Conclusions

High daily steroid dosing, recent pulse steroid therapy, azathioprine, rituximab, concurrent infections, and CMV viremia were mortality risk factors for IA in SLE.

A Rare and Potentially Catastrophic Infection: Primary Intestinal Aspergillosis-Case Report in an HIV Patient

Aspergillus species are ubiquitous in nature; however, infection is uncommon, except in immunocompromised or immunosuppressed hosts. We present the case of a 71-year-old woman with a history of human immunodeficiency virus infection who presented with fever, weight loss, and diarrhea, posteriorly diagnosed with intestinal aspergillosis after examination of a segmental enterectomy piece. The diagnosis was made postmortem once the patient died after fast and progressive deterioration in the postoperative period.

Chitosan stabilized gold nanoparticle mediated self-assembled gliP nanobiosensor for diagnosis of Invasive Aspergillosis

Diagnosis of Invasive Aspergillosis (IA) casused by Aspergillus fumigatus in miniaturized setting is challenging with great importance in human health. In this direction, we have designed a sensitive electrochemical nanobiosensor for diagnosis of IA through detecting the virulent glip target gene (glip-T) in a miniaturized experimetal setting. The sensor probe was fabricated using 1,6-Hexanedithiol and chitosan stabilized gold nanoparticle mediated self-assembly of glip probes (glip-P) on gold electrode. It was characterized by UV-visible spectroscopy, cyclic voltametry and electrochemical impedance spectroscopy. The ability of sensor to detect glip-T was analysed based on the hybridyzation reaction and the signal obtained using toluidine blue as indicator molecule. Analytical parameters were optimized in terms of glip-P concentration, temperature, reaction time, and concentration of toluidine blue. The biosensor showed the dynamic range between 1 × 10^-14- 1 × 10^-2 M with the detection limit of 0.32 ± 0.01 × 10^-14(RSD < 5.2%). The regeneration of biosensor was evaluated and the interference due to non-target oligonucleotide sequences was evaluated individualy as well as in mixed sample to validate the high selectivity of the designed sensor. The stability of the designed sensor was examined and practical applicability of biosensor was tested by detecting glip-T in real sample environment.

Approach to Fungal Infections in Human Immunodeficiency Virus-Infected Individuals: Pneumocystis and Beyond

Many fungi cause pulmonary disease in patients with human immunodeficiency virus (HIV) infection. Pathogens include Pneumocystis jirovecii, Cryptococcus neoformans, Aspergillus spp, Histoplasma capsulatum, Coccidioides spp, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and Emmonsia spp. Because symptoms are frequently nonspecific, a high index of suspicion for fungal infection is required for diagnosis. Clinical manifestations of fungal infection in HIV-infected patients frequently depend on the degree of immunosuppression and the CD4⁺ helper T cell count. Establishing definitive diagnosis is important because treatments differ. Primary and secondary prophylaxes depend on CD4⁺ helper T cell counts, geographic location, and local prevalence of disease.

Mycological Profile of Sputum of HIV Positive Patients with Lower Respiratory Tract Infection and its Correlation with CD4+ T Lymphocyte Count

INTRODUCTION

Fungal respiratory infections are important cause of mortality and morbidity among HIV positive individuals. They account for up to 70% of illness in Acquired Immunodeficiency Disease Syndrome cases (AIDS). The range of illness varies from asymptomatic mucosal candidiasis to overwhelming disseminated infections. In these patients dissemination of fungus leads to very serious outcomes hence, it is important to have the knowledge of prevailing profile of fungus causing infections, so that it can be treated at the onset. Low CD4+ T lymphocyte count is an excellent indicator of decreased immunity and can also be helpful to predict opportunistic fungal respiratory infections and other complications.

AIM

To define the fungal aetiology of lower respiratory tract infections in HIV positive patients and to correlate the occurrence of different fungi with CD4+ T lymphocyte count.

MATERIALS AND METHODS

This was a cross sectional study conducted between May 2014 to April 2015, on 180 treatment naive HIV seropositive patients with lower respiratory tract infections attending the Integrated Counselling and Testing Centre, SMS Medical College, Jaipur, Rajasthan. Early morning expectorated and induced sputum samples were collected and processed for isolation and identification of fungal species. CD4+ T lymphocyte count estimation was done by BD FACS Calibur.

RESULTS

Fungal species were isolated from 155 (86.1%) patients. The most common isolate was Candida albicans (31.7%), followed by Aspergillus niger (17.7%) and Aspergillus flavus (10%). The fungal species were most commonly isolated from patients with CD4+ T lymphocyte cell less than 200 cells/μl.

CONCLUSION

Fungal infections were seen in 86.1% of HIV positive patients with lower respiratory tract infections hence, high level of clinical suspicion for fungal aetiology of respiratory infections in HIV positive patients should be kept in mind.

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Human Neutrophils Use Different Mechanisms To Kill Aspergillus fumigatus Conidia and Hyphae: Evidence from Phagocyte Defects

Neutrophils are known to play a pivotal role in the host defense against Aspergillus infections. This is illustrated by the prevalence of Aspergillus infections in patients with neutropenia or phagocyte functional defects, such as chronic granulomatous disease. However, the mechanisms by which human neutrophils recognize and kill Aspergillus are poorly understood. In this work, we have studied in detail which neutrophil functions, including neutrophil extracellular trap (NET) formation, are involved in the killing of Aspergillus fumigatus conidia and hyphae, using neutrophils from patients with well-defined genetic immunodeficiencies. Recognition of conidia involves integrin CD11b/CD18 (and not dectin-1), which triggers a PI3K-dependent nonoxidative intracellular mechanism of killing. When the conidia escape from early killing and germinate, the extracellular destruction of the Aspergillus hyphae needs opsonization by Abs and involves predominantly recognition via Fcγ receptors, signaling via Syk, PI3K, and protein kinase C to trigger the production of toxic reactive oxygen metabolites by the NADPH oxidase and myeloperoxidase. A. fumigatus induces NET formation; however, NETs did not contribute to A. fumigatus killing. Thus, our findings reveal distinct killing mechanisms of Aspergillus conidia and hyphae by human neutrophils, leading to a comprehensive insight in the innate antifungal response.

Imaging infection

Thoracic imaging is widely used to detect lower respiratory tract infections, identify their complications, and aid in differentiating infectious from noninfectious thoracic disease. Less commonly, the combination of imaging findings and a clinical setting can favor infection with a specific organism. This confluence can occur in cases of bronchiectatic nontuberculous mycobacterial infections in immune-competent hosts, invasive fungal disease among neutropenic patients, Pneumocystis jiroveci pneumonia in patients with AIDS, and in cytomegalovirus infections in patients with recent hematopoietic cell transplantation. These specific diagnoses often depend on computed tomography scanning rather than chest radiography alone.

Clinical characteristics and outcomes in 303 HIV-infected patients with invasive fungal infections: data from the Prospective Antifungal Therapy Alliance registry, a multicenter, observational study

This analysis aimed to characterize the epidemiology, diagnosis, treatment, and outcomes of invasive fungal infections (IFIs) in patients with human immunodeficiency virus (HIV). Data were examined for HIV patients enrolled in the Prospective Antifungal Therapy (PATH) Alliance registry, a multicenter, observational study of patients with IFIs in North America from 2004 to 2008. Patient demographics, clinical characteristics, comorbidities, antifungal therapies, and survival were assessed. In total, 320 fungal isolates were identified from 303 HIV patients with IFIs in the PATH Alliance® registry. These included Cryptococcus (50.0%), Candida (33.1%), Histoplasma (9.1%), and Aspergillus (4.4%). Candida infection occurred mainly as candidemia (86.0%); Cryptococcus as central nervous system infection (76.7%); Histoplasma as disseminated infection (74.1%); and Aspergillus as pulmonary infection (81.8%). The CD4 cell count was ≤200 cells/μL in 91.2% of patients with available data. The majority of patients with Cryptococcus (77.9%), Histoplasma (100.0%), and Aspergillus (71.4%) infections had CD4 cell counts <50 cells/μL compared with 48.9% of patients with Candida infections. Patients with candidiasis were more likely to have other conditions requiring medical services compared with patients with other IFIs. Survival probability was lower in patients with Aspergillus (0.58) and Candida (0.59) infection than in patients with Histoplasma (0.84) and Cryptococcus (0.81) infection. In the highly active antiretroviral therapy era, traditional opportunistic IFIs such as cryptococcosis and histoplasmosis still mainly occur in HIV patients with CD4 counts <50 cells/μL. Fungal infections remain a clinical challenge in HIV patients with severe immunosuppression. Our data also suggest that HIV patients with CD4 cell counts >200 cells/μL and other underlying conditions may be susceptible to invasive candidiasis.

Other HIV-associated pneumonias

The incidence, mortality, and epidemiology of human immunodeficiency virus (HIV)-associated pulmonary infections have changed as a result of effective antiretroviral and prophylaxis antimicrobial therapy. The clinical presentation, radiographic abnormalities, and treatment of pneumonia from various uncommon pathogens in patients with AIDS can be different from those in immunocompetent patients. Advances in invasive and noninvasive testing and molecular biological techniques have improved the diagnosis and prognosis of pulmonary infections in patients infected with HIV. This review focuses on pulmonary infections from nontuberculosis mycobacteria, cytomegalovirus, fungi (aspergillosis, cryptococcosis, endemic fungi), and parasites (toxoplasmosis), and uncommon bacterial pneumonia (nocardiosis, rhodococcosis) in these patients.

Cross-reactivity of Aspergillus galactomannan in an HIV-infected patient with histoplasmosis

Non-invasive assays are increasingly being used in patients with suspected fungal infections. Limitations to these tests include limited sensitivity, specificity, and cross reactivity with other fungal pathogens. Herein we report a case of disseminated histoplasmosis producing a false positive serum and bronchoalveolar lavage (BAL) Aspergillus galactomannan assays. This test may have a role in the evaluation of patients with suspected histoplasmosis in settings where Histoplasma antigen testing is not widely available.

Use of Filgrastim (r-metHuG-CSF) in Human Immunodeficiency Virus Infection

In 2008, an estimated 33.4 million individuals worldwide were infected with the human immunodeficiency virus (HIV) [1]. Only a few years ago, infection with HIV almost invariably culminated in the development of the acquired immunodeficiency syndrome (AIDS), characterized by severe depletion of CD4⁺ lymphocytes leading to derangements predominantly affecting cell-mediated immunity, but affecting humoral immunity as well [2]. In the later stages of AIDS, neutropenia and neutrophil functional deficits were common sequelae of HIV infection, other opportunistic infections, or HIV- or opportunistic infection-related treatment [3]. The care of the HIV-infected patient was palliative in nature, and the possibility that use of filgrastim (rHuG-CSF) might extend survival in late-stage AIDS patients with severe neutropenia or severe opportunistic infections, or might be a treatment for HIV infection itself, was explored [4]. Subsequently, however, the development of protease inhibitors and the widespread adoption of their use in multidrug regimens of highly active antiretroviral therapy (HAART) revolutionized the care of HIV-infected patients, and the number of patients dying from HIV decreased dramatically [5].

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.

Substrate specifity profiling of the Aspergillus fumigatus proteolytic secretome reveals consensus motifs with predominance of Ile/Leu and Phe/Tyr

Background

The filamentous fungus Aspergillus fumigatus (AF) can cause devastating infections in immunocompromised individuals. Early diagnosis improves patient outcomes but remains challenging because of the limitations of current methods. To augment the clinician's toolkit for rapid diagnosis of AF infections, we are investigating AF secreted proteases as novel diagnostic targets. The AF genome encodes up to 100 secreted proteases, but fewer than 15 of these enzymes have been characterized thus far. Given the large number of proteases in the genome, studies focused on individual enzymes may overlook potential diagnostic biomarkers.

Methodology and Principal Findings

As an alternative, we employed a combinatorial library of internally quenched fluorogenic probes (IQFPs) to profile the global proteolytic secretome of an AF clinical isolate in vitro. Comparative protease activity profiling revealed 212 substrate sequences that were cleaved by AF secreted proteases but not by normal human serum. A central finding was that isoleucine, leucine, phenylalanine, and tyrosine predominated at each of the three variable positions of the library (44.1%, 59.1%, and 57.0%, respectively) among substrate sequences cleaved by AF secreted proteases. In contrast, fewer than 10% of the residues at each position of cleaved sequences were cationic or anionic. Consensus substrate motifs were cleaved by thermostable serine proteases that retained activity up to 50°C. Precise proteolytic cleavage sites were reliably determined by a simple, rapid mass spectrometry-based method, revealing predominantly non-prime side specificity. A comparison of the secreted protease activities of three AF clinical isolates revealed consistent protease substrate specificity fingerprints. However, secreted proteases of A. flavus, A. nidulans, and A. terreus strains exhibited striking differences in their proteolytic signatures.

Conclusions

This report provides proof-of-principle for the use of protease substrate specificity profiling to define the proteolytic secretome of Aspergillus fumigatus. Expansion of this technique to protease secretion during infection could lead to development of novel approaches to fungal diagnosis.

A rare, fatal case of invasive spinal aspergillosis in an antiretroviral-naive, HIV-infected man with pre-existing lung colonization

Infection of the central nervous system (CNS) is a rare but devastating complication of invasive aspergillosis. We report a case of invasive aspergillosis with spinal involvement in a human immunodeficiency virus (HIV)-infected patient without neutropenia. A 42-year-old, antiretroviral-naïve, HIV-infected man presented with progressive weakness in the lower limbs and urinary and faecal incontinence for 2 weeks. The patient had been prescribed broad-spectrum antibiotics and prednisone. He had upper motor neuron signs and a sensory level at T1, with accompanying neck stiffness on flexion. Magnetic resonance imaging revealed diffuse abnormal signals of the vertebral bodies in the lower cervical and thoracic areas, with cord compression in the C2 and C3 region and signal distortions of the T2 and T3 vertebral bodies. Chest X-ray and computerized tomography demonstrated post-tuberculous apical cavities with suspected fungal colonization. Histopathology of an extradural spinal lesion at T1/T2 suggested invasive aspergillosis. The patient was started on fluconazole in response to the histopathological evidence of Aspergillus infection, but died within 3 weeks. Post-mortem analysis of the biopsy sample by PCR identified the infectious agent as Aspergillus fumigatus. Atypically, his CD4(+) T-cell count was 239 cells mm(-3) and he had no evidence of neutropenia. Invasive aspergillosis should be considered as part of the differential diagnosis among HIV-infected patients with non-specific, focal CNS symptoms, even among those without classical risk factors such as neutropenia, and aggressive antifungal therapy should be instituted as early as possible.

Infections due to Pseudallescheria/Scedosporium species in patients with advanced HIV disease--a diagnostic and therapeutic challenge

OBJECTIVES

The aim of this study is to highlight the importance of infections caused by members of the genera Pseudallescheria/Scedosporium in HIV-positive patients.

METHODS

We describe a case of a fatal scedosporiosis in a treatment-naïve HIV patient and review all previously reported cases of pseudallescheriosis/scedosporiosis from a search of the PubMed and Deutsches Institut für Medizinische Dokumentation und Information (DIMDI) databases, applying the terms 'Pseudallescheria', 'Scedosporium', 'Allescheria', 'Monosporium', 'Petriellidium', 'boydii', 'prolificans', 'inflatum', cross-referenced with 'HIV' and 'AIDS'.

RESULTS

Detection of Scedosporium and Pseudallescheria species has been reported in 22 HIV-positive patients. Fourteen isolates belonged to the Pseudallescheria boydii complex and eight to Scedosporium prolificans. Invasive scedosporiosis (IS) was proven in 54.5% of the patients. Among them dissemination was observed in 66.7%. Pseudallescheria/Scedosporium species were mainly isolated from male individuals. Patients with proven IS showed CD4+ cell counts <100/μl and a higher co-infection rate as compared to colonized patients. Patients with central nervous system (CNS) manifestations showed CD4+ cell counts <50/μl. The mortality rate for patients with proven IS was 75% and was 100% for patients with dissemination/CNS manifestations. The fatality rate for patients treated with antifungal drugs plus surgery was lower compared to patients treated with antimycotic agents alone.

CONCLUSIONS

IS only occurred in HIV-positive patients with a strongly impaired immune system. The survival rates of patients with advanced HIV disease and invasive scedosporiosis can be improved by rapid diagnosis by biopsy and requires complex therapy with a combination of active antifungal drugs, surgery and supportive immune augmentation.

Hospital epidemiology and infection control in acute-care settings

Health care-associated infections (HAIs) have become more common as medical care has grown more complex and patients have become more complicated. HAIs are associated with significant morbidity, mortality, and cost. Growing rates of HAIs alongside evidence suggesting that active surveillance and infection control practices can prevent HAIs led to the development of hospital epidemiology and infection control programs. The role for infection control programs has grown and continues to grow as rates of antimicrobial resistance rise and HAIs lead to increasing risks to patients and expanding health care costs. In this review, we summarize the history of the development of hospital epidemiology and infection control, common HAIs and the pathogens causing them, and the structure and role of a hospital epidemiology and infection control program.

Epidemiology of invasive aspergillosis and risk factors in non neutropaenic patients

INTRODUCTION

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

STATE OF THE ART

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

PROSPECTS

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

CONCLUSIONS

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

Fungus ball in HIV-infected patients

Aspergillus is a phagocyte opportunistic fungus that causes aspergillosis, an unusual disease in patients with AIDS. Six cases of fungal ball in patients with AIDS are reported here. In this group, all patients had hemoptysis and tuberculosis as the underlying lung disease. The diagnosis of pulmonary fungus ball was based on the clinical and radiographic feature, combined with serological and mycological evidence of Aspergillus fumigatus.

Antifungal drug discovery through the study of invertebrate model hosts

There is an urgent need for new antifungal agents that are both effective and non-toxic in the therapy of systemic mycoses. The model nematode Caenorhabditis elegans has been used both to elucidate evolutionarily conserved components of host-pathogen interactions and to screen large chemical libraries for novel antimicrobial compounds. Here we review the use of C. elegans models in drug discovery and discuss caffeic acid phenethyl ester, a novel antifungal agent identified using an in vivo screening system. C. elegans bioassays allow high-throughput screens of chemical libraries in vivo. This whole-animal system may enable the identification of compounds that modulate immune responses or affect fungal virulence factors that are only expressed during infection. In addition, compounds can be simultaneously screened for antifungal efficacy and toxicity, which may overcome one of the main obstacles in current antimicrobial discovery. A pilot screen for antifungal compounds using this novel C. elegans system identified 15 compounds that prolonged survival of nematodes infected with the medically important human pathogen Candida albicans. One of these compounds, caffeic acid phenethyl ester (CAPE), was an effective antifungal agent in a murine model of systemic candidiasis and had in vitro activity against several fungal species. Interestingly, CAPE is a potent immunomodulator in mammals with several distinct mechanisms of action. The identification of CAPE in a C. elegans screen supports the hypothesis that this model can identify compounds with both antifungal and host immunomodulatory activity.

Respiratory infections in immunocompromised patients

PURPOSE OF REVIEW

Immunosuppressive states and therapies are becoming common in clinical practice. Recent advances and trends in bacterial, fungal, viral and parasitic pulmonary infections in immunosuppressed patients are described.

RECENT FINDINGS

Pulmonary infections can jeopardize the prognosis of immunosuppressed patients. The number of patients infected with multidrug-resistant bacteria or opportunistic pathogens like rapid-growing environmental mycobacteria, Strongyloides stercoralis or Rhodococcus equi is increasing with the increased numbers of immunosuppressed patients due to HIV/AIDS and the potent immunosuppressive therapies used in solid-organ and haematopoietic transplantations, cancer and systemic illnesses. The slow development of more effective antibiotics underlines the necessity of preventive measures, development of rapid detection tests for pathogens and appropriate treatment regimens to avoid development of further resistance.

SUMMARY

Adequate prophylaxis, clinical suspicion, microbiological and molecular investigations, drug susceptibility-based antibiotic treatment and new drug development are strategies required to face up to the challenge of pulmonary infections in immunodepressed patients.

Primary aspergilloma and subacute invasive aspergillosis in two AIDS patients

Although uncommon, invasive aspergillosis in the setting of AIDS is important because of its peculiar clinical presentation and high lethality. This report examines two AIDS patients with a history of severe cellular immunosuppression and previous neutropenia, who developed subacute invasive aspergillosis. One female patient developed primary lung aspergilloma, with dissemination to the mediastinum, vertebrae, and spine, which was fatal despite antifungal treatment. The second patient, who had multiple cavitary brain lesions, and eye and lung involvement, recovered following voriconazole and itraconazole, and drugs for increasing neutrophil and CD4+ lymphocyte levels. These cases demonstrate the importance of Aspergillus infections following neutropenia in AIDS patients, and emphasize the need for early and effective antifungal therapy.

Aspergillus flavus: an emerging non-fumigatus Aspergillus species of significance

Invasive aspergillosis is rare in immunocompetent people but contributes to significant morbidity and mortality in immunosuppressed patients. The majority (approximately 80%) of invasive Aspergillus infections is caused by Aspergillus fumigatus. The second most frequent (approximately 15-20%) pathogenic species is Aspergillus flavus and to a lesser extent, Aspergillus niger and Aspergillus terreus. Aspergillus flavus has emerged as a predominant pathogen in patients with fungal sinusitis and fungal keratitis in several institutions worldwide. To date, there has not been any publication exclusively reviewing the topic of A. flavus in the literature. This article reviews the microbiology, toxigenicity and epidemiology of A. flavus as well as describes the clinical characteristics, diagnosis and management of infections caused by this organism.

Computed tomography for the diagnosis of infectious diseases of the chest

BACKGROUND

Pulmonary infection is a common reason for imaging of the lung in immunocompetent and immunosuppressed patients. Findings on chest radiography are nonspecific and encompass poor sensitivity. The role of computed tomography (CT) has been evolving in the diagnosis of lung infections.

OBJECTIVE

This paper reviews recent developments in the efficacy and utility of CT in the diagnosis of suspected pulmonary infections in a variety of patient populations.

METHODS

Recent published literature was reviewed to prepare this treatise on the role of CT.

CONCLUSION

Knowledge and skills at pattern recognition are crucial for the CT interpretation in lung infections. Computed tomography scan is increasingly used to increase the sensitivity of the radiologic diagnosis of thoracic infections. The greatest value of CT is when the radiograph is normal, findings are equivocal, and to differentiate infection from non-infectious disorders.

Efficient clearance of Aspergillus fumigatus in murine lungs by an ultrashort antimicrobial lipopeptide, palmitoyl-lys-ala-DAla-lys

Aspergillus fumigatus is an opportunistic fungal pathogen responsible for invasive aspergillosis in immunocompromised individuals. The inefficiency of antifungal agents and high mortality rate resulting from invasive aspergillosis remain major clinical concerns. Recently, we reported on a new family of ultrashort cationic lipopeptides active in vitro against fungi. Mode of action studies supported a membranolytic or a detergent-like effect. Here, we screened several lipopeptides in vitro for their anti-A. fumigatus activity. To investigate the therapeutic properties of the selected peptides in vivo, we challenged immunosuppressed C57BL/6 wild-type mice intranasally with DsRed-labeled A. fumigatus conidia and subsequently treated the animals locally with the lipopeptides. Confocal microscopic analysis revealed the degradation of DsRed-labeled hyphal forms and residual conidia in the lungs of the mice. The most efficient peptide was tested further using a survival assay and was found to significantly prolong the life of the treated animals, whereas no mice survived with the current standard antifungal treatment with amphotericin B. Moreover, as opposed to the drug-treated lungs, the peptide-treated lungs did not display any toxicity of the peptide. Our results highlight the potential of this family of lipopeptides for the treatment of pulmonary invasive aspergillosis.

Cavitary pulmonary disease

A pulmonary cavity is a gas-filled area of the lung in the center of a nodule or area of consolidation and may be clinically observed by use of plain chest radiography or computed tomography. Cavities are present in a wide variety of infectious and noninfectious processes. This review discusses the differential diagnosis of pathological processes associated with lung cavities, focusing on infections associated with lung cavities. The goal is to provide the clinician and clinical microbiologist with an overview of the diseases most commonly associated with lung cavities, with attention to the epidemiology and clinical characteristics of the host.