Nonfungal Infections Research Articles

Endemic Fungal Infections in Solid Organ Transplantation

Endemic Fungal Infections in Solid Organ Transplantation

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay

The second-generation MVista Blastomyces antigen enzyme immunoassay was not quantitative; therefore, specimens obtained previously were tested in the same assay as new specimens to assess the change in antigen levels. Furthermore, the sensitivity in serum had not been fully evaluated. The purpose of this study was to evaluate a quantitative Blastomyces antigen assay and detection of antigen in serum. Calibrators containing known concentrations of Blastomyces galactomannan were used to quantify antigen in urine and serum from patients with proven blastomycosis and from controls. Paired current and previously obtained urine specimens were tested to determine if quantification eliminated the need for concurrent testing to assess change in antigen. Pretreatment of serum with EDTA at 104°C was evaluated to determine if dissociation of immune complexes improved detection of antigenemia. Antigenuria was detected in 89.9% of patients with culture- or histopathology-proven blastomycosis. Specificity was 99.0% in patients with nonfungal infections and healthy subjects, but cross-reactions occurred in 95.6% of patients with histoplasmosis. Change in antigen level categorized as increase, no change, or decrease based on antigen units determined in the same assay agreed closely with the category of change in ng/ml determined from different assays. Pretreatment increased the sensitivity of detection of antigenemia from 35.7% to 57.1%. Quantification eliminated the need for concurrent testing of current and previously obtained specimens for assessment of changes in antigen concentration. Pretreatment increased the sensitivity for detection of antigenemia. Differentiation of histoplasmosis and blastomycosis is not possible by antigen detection.

A Multicenter Evaluation of Tests for Diagnosis of Histoplasmosis

The sensitivity of the MVista Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics) has been evaluated in disseminated histoplasmosis in patients with AIDS and in the "epidemic" form of acute pneumonia. Moreover, there has been no evaluation of the sensitivity of antigenemia detection in disseminated histoplasmosis after the implementation of methods to dissociate immune complexes and denature released antibodies. The goal of this study was to determine the sensitivity of the current antigen assay in different categories of histoplasmosis. Urine and serum specimens obtained from 218 patients with histoplasmosis and 229 control subjects, including 30 with blastomycosis, were tested. Antigenuria was detected in 91.8% of 158 patients with disseminated histoplasmosis, 83.3% of 6 patients with acute histoplasmosis, 30.4% of 46 patients with subacute histoplasmosis, and 87.5% of 8 patients with chronic pulmonary histoplasmosis; antigenemia was present in 100% of 31 tested cases of disseminated histoplasmosis. Among patients with disseminated cases, antigenuria was detected more often and at higher concentrations in immunocompromised patients and those with severe disease. Specificity was 99.0% for patients with nonfungal infections (n = 130) and in healthy subjects (n = 69), but cross-reactivity occurred in 90% of patients with blastomycosis. The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.

Evaluation of a latex agglutination test using particles coated with crude exoantigen of Paracoccidioides brasiliensis in the serodiagnosis of paracoccidioidomycosis

INTRODUCTION: Paracoccidioidomycosis (PCM) is a fungal disease caused by the dimorphic agent, P. brasiliensis and is a significant pulmonary mycosis in Latin American countries such as Venezuela, Argentina, and Brazil. The disease commonly manifests as a pulmonary chronic infection with extra-pulmonary lesions, such as those of the oral mucosa. The route of infection for P. brasiliensis is the inhalation of infectious propagules that have developed from the mycelium form of the fungus (25o), and these can convert to the yeast form in the lungs (35o/37o). Patients can present with one of following two clinical forms: the acute clinical form (subacute/juvenile type) or the chronic form (adult type). A definitive diagnosis is made by the visualization or the isolation of the fungus from sputum or bronchoalveolar lavage specimens from patients. As the conventional diagnostic tools are time-consuming and lack the sensitivity of conventional diagnoses, the detection of antibodies from serological assays can also be an effective tool for diagnosis and to monitor the response to treatment. Moreover, the latex agglutination test (LA test) has advantages over these diagnostic tools, such as its rapid execution, and this study demonstrates its effectiveness as a diagnostic test for the serodiagnosis of PCM.OBJECTIVE: The aim of present study was to determine the ability of the LA test to detect antibodies in the sera of PCM patients.MATERIALS AND METHODS: Solutions of 1% latex particles (LA) in CO32-/HCO3- buffer at pH 9.2 were coated with 400 µg crude exoantigen from the yeast form of P. brasiliensis. In the dark, 25 µL of serum from glass slides was homogenized with 25 µL of LA test solution (diluted 1:2 in the same buffer) and incubated for 5 min before the result was visually read. There were 146 samples tested; of these, 51 were from patients with PCM, 11 were from those with histoplasmosis (HP), 15 were from patients with aspergillosis (ASP), 49 were from patients with non-fungal infections (NFI), and 20 of the samples were from normal human serum (HNS). Each of these samples had been previously tested using the immunodiffusion test (ID).RESULTS: From the present study, we obtained 84% sensitivity and 81% specificity for the LA test. The 43 serum samples from PCM patients that were positive by the LA test showed agglutination ranging from a score of one plus (1 +, small clumps with a cloudy background) to four plus (4 +, large clumps with a clear background). The titers were maintained to a dilution of 1:64. The samples from the HP (3/11), ASP (4/15), and NFI (11/49) patients demonstrated cross-reactivity that was not greater than 1 in 4, and no reactivity was observed in the samples of HNS.CONCLUSION: Due to the straightforward and rapid execution of this LA test, these results should have a significant impact on the development of improved diagnostic methods. Moreover, and although the number of samples examined was small, we conclude that the LA test could serve as a future serodiagnostic method. Nevertheless, a characterization of the interfering factors and the elimination of any cross-reactivity are required prior to its application in routine laboratory analysis.

Diagnosis of Histoplasmosis by Antigen Detection in BAL Fluid

Detection of antigen in BAL is useful for diagnosis of histoplasmosis. The MVista Histoplasma antigen enzyme immunoassay has been modified to permit quantification. The purpose of this study is to compare the sensitivity of the quantitative antigen detection assay with cytopathology and culture of BAL specimens. BAL from patients with histoplasmosis who were evaluated at the Indiana University Medical Center and controls without histoplasmosis were studied. BAL fluid was tested in the quantitative Histoplasma antigen assay. Antigen was detected in the BAL in 93.5% of patients with histoplasmosis, 80% with blastomycosis, and 0% of controls with nonfungal infections. Antigen was detected in the urine of 79% and serum in 65% of patients with histoplasmosis. Cytopathology was positive in 48% and culture in 48% of patients with histoplasmosis, and 40% and 60% of patients with blastomycosis, respectively. Serology was positive in 65%. Combining BAL antigen detection and BAL cytopathology, both methods for rapid diagnosis, the sensitivity was 96.8% in histoplasmosis and 80% in blastomycosis. Detection of antigen in BAL complements antigen detection in serum and urine as an objective diagnostic test for histoplasmosis.

Diagnosis of Coccidioidomycosis with Use of theCoccidioidesAntigen Enzyme Immunoassay

We have previously shown antigenuria in patients with coccidioidomycosis through use of the Histoplasma antigen enzyme immunoassay (EIA), and now we have developed a specific Coccidioides antigen EIA. The Coccidioides EIA uses antibodies to Coccidioides galactomannan. The sensitivity of the Coccidioides and Histoplasma EIAs was evaluated in patients with more-severe coccidioidomycosis, and the specificity of these EIAs was evaluated in patients with nonfungal infections, in patients with other endemic mycoses, and in healthy individuals. Among patients in the present study, antigenuria was detected in 70.8% of patients with coccidioidomycosis with use of the Coccidioides EIA and in 58.3% of patients with use of the Histoplasma EIA. Antigenuria was absent in 99.4% of healthy individuals, patients with nonfungal infections, and patients with noninfectious conditions. Cross-reactions with other endemic mycoses were observed in 10.7% of patients. The Coccidioides EIA has potential to be useful in the rapid diagnosis of more-severe forms of coccidioidomycosis.

Results of a Randomized, Double-Blind Trial of Fluconazole (FLU) vs. Voriconazole (VORI) for the Prevention of Invasive Fungal Infections (IFI) in 600 Allogeneic Blood and Marrow Transplant (BMT) Patients.

A multi-center, randomized, double blind trial was performed to determine the impact of FLU (400 mg daily in adults) vs. VORI (200 mg twice daily in adults) on the prevention of IFIs in standard risk allogeneic BMT patients receiving full-intensity conditioning regimens. 600 patients with AML (n=230), ALL (n=122), CML (n=103), MDS (n=98), lymphoma (n=43) and other diseases (n=4) were randomized; 295 to FLU, 305 to VORI between 2003 and 2006 (1 not transplanted). Study drugs were given for 100 days; in those receiving prednisone at a dose of ≥1 mg/kg/day at day 100 or for recipients of T cell depleted grafts with CD4+ counts <200 at day 100, drugs were administered for 180 days. All patients had serum galactomannan (GM) assayed twice weekly for 60 days, then once to twice weekly until day 100, depending on severity of graft versus host disease (GVHD). Positive GM, radiology or the presence of suspicious symptoms or signs triggered intensive evaluation for IFI. Empirical antifungal therapy was permitted for suspected IFI during diagnostic assessment but was limited to ≤14 days. The primary endpoint was freedom from IFI or death at 6 months (fungal-free survival) in the intent to treat cohort. Median recipient age was 43 years (range, 3-66) with 92% >18 years; 55% male; 95% with HLA A, B, and DRB1 matched donor; stem cell graft was related donor marrow or PBSC in 56%. There were no significant differences between the two arms in patient, disease type or risk, or transplant characteristics. Rates of engraftment, acute or chronic GVHD, non-fungal infections, expected or unexpected severe adverse events, and rates of premature study drug withdrawal were similar in both arms (p=NS). At a median follow-up of 12 months, overall survival was 80% at 6 months and 67% at 12 months. A blinded data review committee reviewed source documents of all reported fungal infections, deaths, patients with a positive GM and those given empirical antifungal therapy. There were 25 proven, 30 probable, 15 presumptive, and 74 possible IFIs. The cumulative rates of proven, probable and presumptive IFI were similar in the two arms: 10.6% for FLU and 6.6% for VORI at 6 months (p=0.11) and 13.1% and 11.6% at 12 months (p=0.50), respectively. Microbiologically documented IFIs at 6 months in each arm (FLU and VORI) were caused by Aspergillus (16 and 7, p=0.05), Candida (3 and 3), Zygomycetes (3 and 2), and other (1 and 1). Fungal-free survival rates were similar: 76% for FLU and 78% for VORI at 6 months (p=NS) and 65% and 63% at 12 months (p=NS), respectively. Event-free and overall survival rates also were similar in both arms at 6 and 12 months (p=NS). There were no differences in fungal-free survival rates in patients who received prophylactic fluconazole or voriconazole when intensive monitoring and early empirical therapy were employed in standard risk allogeneic BMT recipients.

Comparison of Fungal and Nonfungal Infections in a Broad-Based Surgical Patient Population

Our aim was to compare fungal and nonfungal infections among a diverse surgical patient population. Data on all hospital-acquired infectious episodes among surgical intensive care unit and ward patients were collected prospectively over six years at a single university hospital. The relationships between fungal and nonfungal infection and over 100 variables were examined using univariate and multiple logistic regression analysis. During the study period, 3,980 infectious episodes were identified; 554 were associated with fungal infection. Multiple logistic regression analysis demonstrated that markers of severity of acute illness (higher APACHE II scores and white blood cell counts, greater transfusion of cellular blood products, mechanical ventilator dependency, and prior infection) predicted fungal infection, whereas markers of chronic illness (comorbidities) did not independently predict either fungal or nonfungal infection. Patients with fungal infection were treated with more antibiotics for longer periods of time, had prolonged lengths of stay, and more often died compared with nonfungal infection patients. A separate multiple logistic regression analysis demonstrated that both fungal infection and the number of fungal sites of infection independently predicted mortality. Of all fungal isolates, only Candida albicans and Aspergillus spp. independently predicted mortality. Fungal infections differ significantly in character and outcomes from nonfungal infections among surgical patients.

Invasive Fungal Infections in Pediatric Oncology Patients

The purpose of this study was to determine the incidence of fungal infections in pediatric hematology and oncology (PHO) patients and to describe variations regarding site of infection, organisms, and mortality. The records of 1,052 patients presenting to the UCLA PHO service with various malignancies from 1991 to 2001 were retrospectively reviewed. No patient received invasive antifungal prophylaxis. Transplant patients were excluded. The 11-year incidence of fungal infections in this pediatric oncology cohort was 4.9%. There was a linear increase in the incidence of fungal infections from 2.9% to 7.8% between 1996 and 2001 (P = 0.001). Patients with acute leukemia represented 36% of the population but had a disproportionate incidence (67%) of fungal infections. Adolescents had twice the expected incidence of infection (P < 0.0001). Overall, Candida sp. was the major pathogen. Over time, a trend of fewer infections caused by Candida and more due to Aspergillus was noted. Blood-borne infections decreased over time, while those in the urinary and respiratory tracts increased (P = 0.04). Sixty-two percent of infections occurred in neutropenic patients. PHO patients had an overall mortality of 21%, but those with fungal infections experienced a 2.6-fold higher mortality that was not attributable to infections alone. Empiric antifungal therapy had no effect on mortality rates. Concurrent nonfungal infections did not increase mortality rates. The incidence of fungal infections increased over time, possibly as a result of advances in antibacterial and chemotherapeutic regimens. Adolescents and patients with leukemia were especially at risk. Fungal infections are a poor prognostic factor, independent of fungal-related mortality. New diagnostic methods allowing for early detection and treatment as well as more effective therapies are needed.

Low-Dose Amphotericin B Lipid Complex for the Treatment of Persistent Fever of Unknown Origin in Patients with Hematologic Malignancies and Prolonged Neutropenia

We studied the safety of low-dose amphotericin B lipid complex (ABLC, at 1 mg/kg/day) in 30 persistently febrile (>38°C for at least 5 days or with recurrent fever after 3 days of apyrexia) and neutropenic (<0.5 × 10⁹/l) adult patients with hematologic malignancies. The median age was 45 years (range 18–67), most (60%) had an acute leukemia and all had fever of unknown origin (FUO). The total duration of neutropenia was a median of 17 days (range 9–33), and the total number of days with fever 10 days (range 6–39). Seven patients experienced mild-to- moderate infusion-related adverse events (IRAE). The serum creatinine and urea increased from baseline to end of therapy in 76 and 63% of cases, but the maximum levels reached were <130 µmol/l and <11 mmol/l, respectively, in all cases. Liver enzymes showed modest but significant increases in most patients during therapy, while bilirubin decreased in 74% of cases. Response to treatment (defervescence within 6 days without developing a fungal or nonfungal infection) was seen in 22 cases (73%, 95% CI 58–89%), while 8 episodes were considered treatment failures: 2 due to persistent FUO, 1 withdrew due to IRAE, 2 developed nonfungal infections and 3 developed a presumed or definite invasive mycosis. We conclude that low-dose ABLC is very safe and well tolerated and seems as effective as c-AmB for this indication. Thus, randomized trials at this dose level appear justified to demonstrate any real benefit over c-AmB or other lipid formulations for the treatment of FUO in neutropenic patients.

Plasma (1→3)-β-D-glucan measurement in diagnosis of invasive deep mycosis and fungal febrile episodes

Summary (1→3)-β-D-glucan is a characteristic fungal cell-wall constituent. To assess the clinical usefulness of this glucan in screening for invasive fungal infection or fungal febrile episodes, we measured the plasma concentration at the time of routine blood culture in 202 febrile episodes by means of factor G, a horseshoe-crab coagulation enzyme that is extremely sensitive to this polysaccharide. With a plasma cut-off value of 20 pg/mL, 37 of 41 episodes of definite fungal infections (confirmed at necropsy or by microbiology) had positive results (sensitivity 90%). All of 59 episodes of non-fungal infections, tumour fever, or collagen diseases had concentrations below the cut-off value (specificity 100%). Of 102 episodes of fever of unknown origin, 26 had plasma glucan concentrations of more than 20 pg/mL. With those 102 cases taken as non-fungal infections, the positive predictive value of the test was estimated as 59% (37/63), the negative predictive value as 97% (135/139), and the efficiency as 85% (172/202). The positive predictive value should improve if there were a sensitive gold standard that could discriminate fungal from non-fungal infections. Causative fungi included candida, aspergillus, cryptococcus, and trichosporon. Determination of plasma (1→3)-β-D-glucan with factor G is a highly sensitive and specific test for invasive deep mycosis and fungal febrile episodes, and will substantially benefit immunocompromised patients.

Cotrimoxazole reduces nonfungal infections in chronic GD

Cotrimoxazole reduces nonfungal infections in chronic GD

Trimethoprim-Sulfamethoxazole Prophylaxis in the Management of Chronic Granulomatous Disease

Long-term oral antimicrobial prophylaxis is accepted practice in the management of patients with chronic granulomatous disease (CGD). Reports of adverse outcome with trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis in other patient groups, and the recent occurrence of several severe fungal infections in patients followed at the National Institutes of Health (NIH), prompted a review of the NIH experience to examine the incidence of nonfungal and fungal infections in CGD patients with and without TMP-SMX prophylaxis. Prophylaxis decreased the incidence of nonfungal infections from 7.1 to 2.4 per 100 patient-months in patients with autosomal CGD (P less than .01) and from 15.8 to 6.9 infections per 100 patient-months (P = .06) in X-linked CGD patients. There was no significant change in the incidence of fungal infection in CGD patients on TMP-SMX (1.5-0.3 fungal infections/100 patient-months in autosomal CGD and 1.7-0.2 fungal infections/100 patient-months in X-linked CGD patients). TMP-SMX prophylaxis is indicated for the management of patients with CGD and decreases the incidence of non-fungal infections without increasing the incidence of fungal infections.

The role of fiberoptic bronchoscopy in the evaluation of immunocompromised hosts with diffuse pulmonary infiltrates.

To define the utility of fiberoptic bronchoscopy in the evaluation of immunocompromised patients with diffuse pulmonary infiltrates, we reviewed our experience between January 1980, and January 1983, with 50 such patients with a wide variety of underlying diseases. Of these, 35 patients underwent bronchoscopy, including brushings, alveolar lavage, and transbronchial biopsy, and 15 underwent open lung biopsy; 8 patients underwent both procedures. All patients with a nondiagnostic bronchoscopy either recovered without specific antibiotic therapy or underwent an open procedure. A diagnosis was made in 29 patients (58%). An infectious process was found in 20 patients (40%). A diagnosis was made bronchoscopically in 19 patients including 18 infections. Transbronchial biopsy was rarely diagnostic of infection when brushings were negative. For all diagnoses, bronchoscopy had a sensitivity of 76.9%. For all pulmonary infections, bronchoscopy had a sensitivity of 90%. Given a negative bronchoscopy, the probability that an infection was not present (i.e., predictive value negative) was 94.4%. Unfortunately, making a specific diagnosis did not appear to greatly improve survival. We conclude that in this setting: (1) fiberoptic bronchoscopy is an extremely sensitive procedure for diagnosing pulmonary infections, (2) bronchial brushings are as useful as transbronchial biopsies for diagnosing nonfungal infections, (3) these procedures are less useful for diagnosing noninfectious conditions, and (4) in the face of a negative bronchoscopic procedure, there is a very low probability that an infectious process will be found with an open biopsy.

Fungal Infection Following Renal Transplantation

Twenty-seven deep fungal infections developed in 22 of 171 patients following renal transplantation. These infections included cryptococcosis (ten), nocardiosis (seven), candidiasis (four), aspergillosis (two), phycomycosis (two), chromomycosis (one), and subcutaneous infection with Phialophora gougeroti (one). Twelve infections occurred in living-related and ten in cadaveric recipients. Nineteen of the 22 patients were male. Infections occurred from 0 to 61 months after transplantation. Complicating non-fungal infections were present concomitantly in 15 patients. Thirteen patients died, eight probably as a result of fungal infection. Appropriate diagnostic procedures yielded a diagnosis in 20 of 27 infections, and therapy was begun in 18 patients. Serologic, culture, and biopsy procedures useful in making rapid diagnoses are advocated in the hope of increasing survival.

Fungal infection following renal transplantation

Twenty-seven deep fungal infections developed in 22 of 171 patients following renal transplantation. These infections included cryptococcosis (ten), nocardiosis (seven), candidiasis (four), aspergillosis (two), phycomycosis (two), chromomycosis (one), and subcutaneous infection with<i>Phialophora gougeroti</i>(one). Twelve infections occurred in living-related and ten in cadaveric recipients. Nineteen of the 22 patients were male. Infections occurred from 0 to 61 months after transplantation. Complicating nonfungal infections were present concomitantly in 15 patients. Thirteen patients died, eight probably as a result of fungal infection. Appropriate diagnostic procedures yielded a diagnosis in 20 of 27 infections, and therapy was begun in 18 patients. Serologic, culture, and biopsy procedures useful in making rapid diagnoses are advocated in the hope of increasing survival.