Identification of the Most Immunoreactive Antigens of Candida auris to IgGs from Systemic Infections in Mice.

The delay in making a correct diagnosis of Candida auris causes concern in the healthcare system setting, and immunoproteomics studies are important to identify immunoreactive proteins for new diagnostic strategies. In this study, immunocompetent murine systemic infections caused by non-aggregative and aggregative phenotypes of C. auris and by Candida albicans and Candida haemulonii were carried out, and the obtained sera were used to study their immunoreactivity against C. auris proteins. The results showed higher virulence, in terms of infection signs, weight loss, and histopathological damage, of the non-aggregative isolate. Moreover, C. auris was less virulent than C. albicans but more than C. haemulonii. Regarding the immunoproteomics study, 13 spots recognized by sera from mice infected with both C. auris phenotypes and analyzed by mass spectrometry corresponded to enolase, phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase, and phosphoglycerate mutase. These four proteins were also recognized by sera obtained from human patients with disseminated C. auris infection but not by sera obtained from mice infected with C. albicans or Aspergillus fumigatus. Spot identification data are available via ProteomeXchange with the identifier PXD049077. In conclusion, this study showed that the identified proteins could be potential candidates to be studied as new diagnostic or even therapeutic targets for C. auris.

Dextrose-containing fluids causing false-positive serum galactomannan: a case-control study and interrupted time series analysis.

OBJECTIVES: This study aimed to identify the cause of false-positive serum Aspergillus antigen galactomannan (GM) results in our centre. METHODS: We performed a case-control study aiming to elucidate the factors associated with false-positive GM results. Independent risk factors for false-positive GM were evaluated through a multivariable regression analysis. An interrupted time series analysis was used to evaluate the effectiveness of an intervention removing the identified factors. RESULTS: Among 568 patients tested, GM was positive in 130 patients of whom 97 had false-positive GM (cases). These were compared with 427 patients with true-negative GM (controls). Administration of dextrose-containing fluids within 6 days before GM testing was an independent predictor for false-positive GM results (adjusted odds ratio [aOR], 18.60; 95% CI, 8.95-38.66. An analysis of GM presence in different dextrose-containing fluids revealed positivity in 34.8% (8 of 23) (manufacturer A) and 33.3% (5 of 15) (manufacturer B) of the samples. Investigation of the manufacturing process revealed that the saccharification process employed enzymes derived from Aspergillus niger. After identifying the root cause of false positivity, GM-containing dextrose fluid use was restricted. Interrupted time series analysis showed an immediate reduction of GM false-positivity (-6.5% per week, p = 0.045) and a declining trend (-0.33% per week, p = 0.005) postintervention. CONCLUSIONS: Administering dextrose-containing fluids was the primary factor causing false-positive serum Aspergillus antigen GM assay results. Our investigation led to a modification of the manufacturing process of the dextrose-containing fluids.

Diagnostic value of galactomannan antigen test in serum and bronchoalveolar lavage fluid sample from suspected patients of invasive pulmonary aspergillosis.

Invasive pulmonary aspergillosis (IPA) is mainly caused by Aspergillus fumigatus and other Aspergillus species. Galactomannan (GM) is a polysaccharide antigen that exists primarily in the cell walls of Aspergillus species. GM may be released into the blood and other body fluids even in the early stages of Aspergillus invasion; therefore, detection of the GM antigen level can be useful in making an early diagnosis of IPA.

Prevalence of Advanced HIV Disease, Cryptococcal Antigenemia, and Suboptimal Clinical Outcomes Among Those Enrolled in Care in Vietnam.

BACKGROUND: People living with advanced HIV disease are at high risk of morbidity and mortality. We assessed the prevalence of cryptococcal antigenemia (CrAg) and clinical outcomes among patients newly presenting with CD4 ≤100 cells/µL in Vietnam. SETTING: Twenty-two public HIV clinics in Vietnam. METHODS: During August 2015-March 2017, antiretroviral therapy (ART)-naïve adults presenting for care with CD4 ≤100 cells/µL were screened for CrAg. Those who consented to study enrollment were followed up for up to 12 months and assessed for clinical outcomes. RESULTS: Of 3504 patients with CD4 results, 1354 (38.6%) had CD4 ≤100 cells/µL, of whom 1177 (86.9%) enrolled in the study. The median age was 35 years (interquartile range 30-40); 872 (74.1%) of them were men, and 892 (75.8%) had CD4 <50 cells/µL. Thirty-six patients (3.1%) were CrAg-positive. Overall, 1151 (97.8%) including all who were CrAg-positive initiated ART. Of 881 patients (76.5%) followed up for ≥12 months, 623 (70.7%) were still alive and on ART at 12 months, 54 (6.1%) had transferred to nonstudy clinics, 86 (9.8%) were lost to follow-up, and 104 (11.8%) had died. Among all 1177 study participants, 143 (12.1%) died, most of them (123, 86.0%) before or within 6 months of enrollment. Twenty-seven patients (18.9%) died of pulmonary tuberculosis, 23 (16.1%) died of extrapulmonary tuberculosis, 8 (5.6%) died of Talaromyces marneffei infection, and 6 (4.2%) died of opioid overdose. Eight deaths (5.8%) occurred among the 36 CrAg-positive individuals. CONCLUSIONS: Late presentation for HIV care was common. The high mortality after entry in care calls for strengthening of the management of advanced HIV disease.

Cryptococcal antigen carriage among HIV infected children aged 6 months to 15 years at Laquintinie Hospital in Douala.

BACKGROUND: Up to 15% of deaths of people living with HIV is attributable to meningeal cryptococcosis, with nearly 75% occuring in sub-Saharan Africa. Although rare in children, it is a major cause of morbidity and mortality in people living with HIV. A strong association between cryptococcal antigenemia and the development of meningeal cryptococcosis has been shown in adults. Thus, in 2018, the World Health Organization published an updated version of its guidelines for the diagnosis, prevention and management of cryptococcal infection in adults, adolescents and the HIV-infected child. GOAL: To determine the prevalence of cryptococcal antigenemia and to identify its determinants in children infected with HIV. METHODS: An analytical cross-sectional study was carried out at the approved treatment center of Laquintinie hospital in Douala over a period of 4 months. Children were recruited consecutively after informed parental consent. Cryptococcal antigenemia and CD4 assay were performed using a Cryptops® immunochromatographic rapid diagnostic test and flow cytometry, respectively. The data collected included the socio-demographic, clinical and paraclinical variables of the children, as well as their antecedents. Data analysis was performed using Epiinfo software version 3.1 and SPSS 21.0. The significance threshold was set at 5%. RESULTS: A total of 147 children were enrolled. The mean age was 9.8 ± 4.09 years. The majority were on antiretroviral therapy (142, 96.60%). Only 13 (8.80%) were in severe immunosuppression. No child showed signs of meningeal cryptococcosis. The prevalence of cryptococcal antigenemia was 6.12%. Severe immunosuppression [OR: 10.03 (1.52-65.91), p = 0.016] and contact with pigeons [OR: 9.76 (1.14-83.65), p = 0.037] were independent factors significantly associated with the carriage of the cryptococcal antigen. CONCLUSION: We recommend screening for cryptococcal antigenemia and routine treatment with fluconazole of all HIV positive children with cryptococcal antigen whether symptomatic or not.

Serum Lateral Flow assay with digital reader for the diagnosis of invasive pulmonary aspergillosis: A two-centre mixed cohort study.

BACKGROUND: Detection of galactomannan (GM) from bronchoalveolar lavage fluid (BALF) or serum is broadly used for diagnosis of invasive aspergillosis (IA), although the sensitivity of GM from serum is lower in non-neutropenic patients. We evaluated the Aspergillus galactomannan Lateral Flow assay (LFA) with digital readout from serum in a mixed cohort of patients. METHODS: We performed a retrospective two-centre study evaluating the LFA from serum of patients with clinical suspicion of IA obtained between 2015 and 2021 at the University of California San Diego and the Medical University of Graz. The sensitivity and specificity was calculated for proven/probable aspergillosis versus no aspergillosis. Correlation with same-sample GM was calculated using Spearman correlation analysis and kappa statistics. RESULTS: In total, 122 serum samples from 122 patients were analysed, including proven IA (n = 1), probable IA or coronavirus-associated pulmonary aspergillosis (CAPA) (n = 27), and no IA/CAPA/non-classifiable (n = 94). At a 0.5 ODI cut-off, the sensitivity and specificity of the LFA was 78.6% and 80.5%. Spearman correlation analysis showed a strong correlation between serum LFA ODI and serum GM ODI (ρ 0.459, p < .0001). Kappa was 0.611 when both LFA and GM were used with a 0.5 ODI cut-off, showing substantial agreement (p < .001). DISCUSSION: The LFA with digital read out from serum showed good performance for the diagnosis of probable/proven aspergillosis, with substantial agreement to GM from serum. Like the LFA from BALF, the LFA from serum may serve as a more rapid test compared to conventional GM, particularly in settings where GM is not readily available.

Combining urine antigen and blood polymerase chain reaction for the diagnosis of disseminated histoplasmosis in hospitalized patients with advanced HIV disease.

Disseminated histoplasmosis (DH) is endemic in Latin America and the Caribbean where diagnostic tools are restricted. We carried-out a 1-year prospective cohort study at a referral hospital in São Paulo, Brazil. Participants had > or =18 years old, were hospitalized due to any indication and had CD4+ < 200 cells/µl. A urine commercial monoclonal Histoplasma galactomannan enzyme-linked immunosorbent assay (IMMY, Norman, OK, USA) and 'in house' Histoplasma blood nested PCR were performed in all cases. Probable/proven DH cases were defined according to international guidelines. Conventional mycological methods were available in routine conditions to investigate suspected DH cases. Treatment of participants followed the institutional routine. One-hundred six participants were included. Median age (interquartile range [IQR]) was 39.5 years (30.0-47.3) and 80 individuals (75.5%) were males. Median (IQR) CD4 cell count was 26.5 (9.4-89.3) cells/mm3. DH was diagnosed in 8/106 patients (7.5%). Antigen assay and/or PCR were positive in 4.7% (5/106) of patients. The antigen assay and/or PCR identified 37.5% (3/8) of DH cases, which had not been diagnosed with conventional mycological methods, but had clinical manifestations compatible with HD. In conclusion, the use of Histoplasma urine antigen and Histoplasma blood PCR guided by CD4 status contributed to the diagnosis of DH in hospitalized individuals. These assays were complementary to conventional mycologic methods and are urgently needed in our setting. LAY SUMMARY: In this prospective cohort study carried-out in a referral center in São Paulo, Brazil, we found a high frequency of AIDS-related disseminated histoplasmosis (8/106, 7.5%). We used urine antigen test and blood PCR assay to improve the diagnosis of this opportunistic disease.

Implementation of rapid diagnostics assays for detection of histoplasmosis and cryptococcosis in central american people living with HIV.

OBJECTIVES: Histoplasmosis and cryptococcosis are important public health problems in people living with HIV (PLHIV) in Central America. Conventional laboratory assays, based on microscopy and culture, are not optimal for the diagnosis of either disease. However, antigen (Ag) assays are rapid and highly accurate for the diagnosis of these infections. METHODS: Laboratory surveillance of PLHIV was carried out in four hospitals in Panama, Honduras and Nicaragua, between 2015 and 2019. Detection of Histoplasma antigens in urine was performed by enzyme immunoassay (EIA), and Cryptococcus antigen detection in sera and cerebrospinal fluid specimens was performed by lateral flow assay (LFA). RESULTS: A total of 4,453 PLHIV with clinical suspicion of histoplasmosis (n = 1,343) or cryptococcosis (n = 3,110; 2,721 sera and 389 CSF) were tested. Of 1,343 patients suspected of having histoplasmosis, 269 (20%) were Histoplasma Ag positive. Of 3,110 patients tested using the Cryptococcus Ag assay, 329 (11%) were positive. Honduras reported the highest positivity rates (32% for Histoplasma Ag, and 16% for Cryptococcus Ag); Panama reported the largest number of patients testing positive using the Histoplasma Ag assay (n = 201); and Nicaragua reported the largest number of patients testing positive using the Cryptococcus Ag assay (n = 170). CONCLUSION: Here, we show how the implementation of rapid diagnostics assays impacted case detection and was useful for the care of people with advanced HIV. Rapid and accurate diagnosis could reduce mortality associated with histoplasmosis and cryptococcosis in PLHIV.

Dissection of the anti-Candida albicans mannan immune response using synthetic oligomannosides reveals unique properties of ß-1,2 mannotriose protective epitopes.

Candida albicans mannan consists of a large repertoire of oligomannosides with different types of mannose linkages and chain lengths, which act as individual epitopes with more or less overlapping antibody specificities. Although anti-C. albicans mannan antibody levels are monitored for diagnostic purposes nothing is known about the qualitative distribution of these antibodies in terms of epitope specificity. We addressed this question using a bank of previously synthesized biotin sulfone tagged oligomannosides (BSTOs) of α and ß anomery complemented with a synthetic ß-mannotriose described as a protective epitope. The reactivity of these BSTOs was analyzed with IgM isotype monoclonal antibodies (MAbs) of known specificity, polyclonal sera from patients colonized or infected with C. albicans, and mannose binding lectin (MBL). Surface plasmon resonance (SPR) and multiple analyte profiling (MAP) were used. Both methods confirmed the usual reactivity of MAbs against either α or ß linkages, excepted for MAb B6.1 (protective epitope) reacting with ß-Man whereas the corresponding BSTO reacted with anti-α-Man. These results were confirmed in western blots with native C. albicans antigens. Using patients' sera in MAP, a significant correlation was observed between the detection of anti-mannan antibodies recognizing ß- and α-Man epitopes and detection of antibodies against ß-linked mannotriose suggesting that this epitope also reacts with human polyclonal antibodies of both specificities. By contrast, the reactivity of human sera with other α- and ß-linked BSTOs clearly differed according to their colonized or infected status. In these cases, the establishment of an α/ß ratio was extremely discriminant. Finally SPR with MBL, an important lectin of innate immunity to C. albicans, classically known to interact with α-mannose, also interacted in an unexpected way with the protective epitope. These cumulative data suggest that structure/activity investigations of the finely tuned C. albicans anti-mannose immune response are worthwhile to increase our basic knowledge and for translation in medicine.

Diagnostic value of serum human Galactomannan aspergillus antigen and 1,3-beta-D-glucan in immunocompromised patient suspected fungal infection.

BACKGROUND: The prevalence of fungal infection (FI) in developing countries is high, but the diagnosis of FI is still challenging to determine, so it is needed evaluation of biomarkers other than microbiological culture, because the culture has low sensitivity, high cost, not available in every laboratory and needs a long time. The detection of human galactomannan Aspergillus antigen (GAL) and 1,3-beta-D-glucan (BDG) on the fungal cell wall could be the promising biomarkers for fungal infection. Neutropenia, lymphopenia and CD4T cells in the immunocompromised patients are essential factors, but these cell associations with BDG and GAL levels have not been evaluated yet. The study aimed to evaluate GAL and BDG for detecting fungal infection and their association with total leucocyte count, neutrophil, monocyte, lymphocyte and CD4T cells. METHOD: A cross-sectional study was conducted among 86 patient with suspected FI. Fungal infection established using EORTC/MSG criteria. Serology test performed using ELISA. Leucocyte cells were measured using a haematology autoanalyser, and CD4T cells were analysed using BD FACSPresto. Statistical analysis obtained using Spearman's correlation coefficient, ROC curve analysis and 2 × 2 contingency table. RESULTS: Serum Galactomannan and BDG had a significant correlation with CD4T cells and total lymphocyte count (p < 0.05). The cut-off OD GAL >0.3 had sensitivity 54.6%, specificity 87.5% and AUC 0.71; meanwhile, the BDG cut-off >115.78 pg/ mL had sensitivity 71.2%, specificity 52.4% and AUC 0.63 for detecting fungal infection. CONCLUSIONS: The immunocompromised patients can undergo GAL for determining the diagnose of FI. The lower the CD4T cells and total lymphocyte count, the higher the GAL and BDG serum levels.

High prevalence of Cryptococcal antigenemia using a finger-prick lateral flow assay in individuals with advanced HIV disease in Santarém Municipality, Brazilian Amazon Basin.

There is scarce information about HIV-related cryptococcosis in the Brazilian Amazon basin where laboratory infrastructure is limited. The serum cryptococcal antigen (CrAg) lateral flow assay (LFA) has simplified diagnosis of cryptococcosis and is recommended for screening in advanced HIV disease. We evaluated the prevalence of cryptococcal antigenemia using finger-prick CrAg LFA in the Brazilian Amazon basin. We enrolled a prospective cohort of outpatients and hospitalized individuals with advanced HIV disease at two centers in Santarém Municipality, Northern Brazil. All individuals were > 18 years old with advanced HIV disease, regardless of antiretroviral therapy (ART) status and with no prior or current history of confirmed cryptococcal meningitis. We tested CrAg LFA on finger-prick whole blood using an exact volume transfer pipette. From August 2018 to October 2019, 104 individuals were enrolled (outpatients 62 [60%] and hospitalized 42 [40%]). Median age was 38 years (interquartile range [IQR] 30-46), and 84 (81%) were male. Sixty-five (63%) individuals were ART-naïve. Prevalence of finger-prick CrAg LFA-positive was 10.6%; 95% CI, 5.4 to 18.1%. Prevalence of finger-prick CrAg LFA-positive among individuals without neurological symptoms was 6.0%; 95% CI, 1.7-14.6%. The number needed to test to detect one CrAg-positive individual was 9.4 persons (95% CI, 5.5-18.5). Prevalence of cryptococcal antigenemia using finger-prick whole blood CrAg LFA was high. Point-of-care approach was important for the diagnosis and screening of cryptococcosis in resource-limited settings. Screening and preemptive therapy strategy should be urgently implemented in individuals with advanced HIV disease in the Brazilian Amazon basin.

This prospective cohort study was carried-out in the Brazilian Amazon basin. We used a cryptococcal rapid test in patients with AIDS. We included 104 participants, and 11 (10.6%) of them had positive results showing a high prevalence of cryptococcal antigenemia.

Serum Aspergillus galactomannan lateral flow assay for the diagnosis of invasive aspergillosis: A single-centre study.

BACKGROUND: Aspergillus species meet the most important group of invasive fungal diseases (IFD) in immunosuppressed patients. Galactomannan is a polysaccharide antigen located in the wall structure of Aspergillus. The most commonly used method for antigen detection is enzyme-linked immunoassay (ELISA). Aspergillus galactomannan lateral flow assay (LFA) constitutes one of the new methods in the diagnosis of invasive aspergillosis (IA). The goal of this study was to demonstrate efficacy of LFA in our patients and to compare it to synchronous ELISA results. METHODS: Galactomannan antigen was examined using both LFA and ELISA in serum samples taken from patients who were followed up in our haematology clinic. All patients are classified in subgroups as 'proven', 'probable' and 'possible' patients according to the last EORTC / MSG guideline. Patients who met the 'proven' IA criteria were included in the study as the gold standard. RESULTS: A total of 87 patients were included in the study. Majority of patients had acute myeloid leukaemia (AML) (56.3%). Eleven (12.6%) were in 'proven' IA group. LFA test showed a superior diagnostic performance compared with ELISA (LFAAUC  = 0.934 vs ELISAAUC  = 0.545; p < .001). The LFA had a sensitivity of 90.9% and a specificity of 90.8% for '0.5 ODI' in predicting IA (PPV = 55.8%; NPV = 98.6%; p < .001). CONCLUSION: The most important finding of this study is that the specificity of LFA was found to be higher for cut-off value of 0.5. It is recommended to combine the methods in many studies to provide a better early diagnosis for IA.

An unusual case of reactivated latent pulmonary cryptococcal infection in a patient after short-term steroid and azathioprine therapy: a case report.

BACKGROUND: Cryptococcus is one of the major fungal pathogens infecting the lungs. Pulmonary cryptococcal infection is generally considered a community-acquired condition caused by inhalation of dust contaminated with fungal cells from the environment. Here, we report a case developing pulmonary cryptococcosis 3 months after hospital admission, which has rarely been reported before. CASE PRESENTATION: A 73-year-old female patient who was previously immunocompetent experienced persistent dry cough for 2 weeks, 3 months after admission. Chest computed tomography (CT) showed a new solitary pulmonary nodule developed in the upper lobe of the left lung. Staining and culture of expectorated sputum smears were negative for bacteria, acid-fast bacilli, or fungus. The patient then underwent biopsy of the lesion. Histopathology findings and a positive serum cryptococcal antigen titer (1:8) indicated pulmonary cryptococcosis. Daily intravenous 400 mg fluconazole was administered initially followed by oral fluconazole therapy. Follow-up chest CT after 3 months of antifungal therapy showed complete disappearance of the pulmonary nodule. Respiratory symptoms of the patient also resolved. A complete investigation excluded the possibility of a patient-to-patient transmission or primarily acquiring the infection from the hospital environment. Based on the patient's history of exposure to pigeons before admission and recent steroid and azathioprine use after admission for the treatment of myasthenic crisis, reactivation of a latent pulmonary cryptococcal infection acquired before admission, in this case, is impressed. CONCLUSIONS: Although rarely reported, pulmonary cryptococcal infection should be included in the differential diagnosis of hospitalized patients with respiratory symptoms, especially in those with predisposing risk factors. Chest image studies and further surgical biopsy are needed for confirmation.

Serological Proteome Analysis for the Characterization of Secreted Fungal Protein Antigens.

Defining the humoral immune response to infectious agents is important for gaining insights into infectious diseases and the response of the immune system. It can further aid development of serodiagnostic tests, discovery of vaccine antigen candidates, and immuno-epidemiological research. During the last three decades, serological proteome analyses (SERPAs) have played a significant role in characterizing the antibody response of humans or animals to fungal pathogens. SERPA combines 2D-gel electrophoresis with Western blotting. The introduction of multiplexing approaches by means of fluorescent dyes has greatly improved the reliability of the 2D technique and has boosted also the qualitative capabilities of the SERPA approach. In this chapter, we detail a SERPA protocol using fungal extracellular proteins from a fungal culture, here as an example the mold Aspergillus fumigatus.

Two Monoclonal Antibodies That Specifically Recognize Aspergillus Cell Wall Antigens and Can Detect Circulating Antigens in Infected Mice.

Invasive aspergillosis (IA) is a life-threatening disease mainly caused by Aspergillus fumigatus and Aspergillus flavus. Early diagnosis of this condition is crucial for patient treatment and survival. As current diagnostic techniques for IA lack sufficient accuracy, we have raised two monoclonal antibodies (1D2 and 4E4) against A. fumigatus cell wall fragments that may provide a platform for a new diagnostic approach. The immunoreactivity of these antibodies was tested by immunofluorescence and ELISA against various Aspergillus and Candida species in vitro and by immunohistochemistry in A. fumigatus infected mouse tissues. Both monoclonal antibodies (mAbs) showed intensive fluorescence with the hyphae wall of A. fumigatus and A. flavus, but there was no staining with other Aspergillus species or Candida species. Both mAbs also showed strong immunoreactivity to the cell wall of A. fumigatus hyphae in the infected liver, spleen and kidney of mice with IA. The antigens identified by 1D2 and 4E4 might be glycoproteins and the epitopes are most likely a protein or peptide rather than a carbohydrate. An antibody-based antigen capture ELISA detected the extracellular antigens released by A. fumigatus, A. flavus, A. niger and A. terreus, but not in Candida species. The antigen could be detected in the plasma of mice after 48 h of infection by double-sandwich ELISA. In conclusion, both 1D2 and 4E4 mAbs are potentially promising diagnostic tools to investigate invasive aspergillosis.

Cryptococcal meningitis: a review of cryptococcal antigen screening programs in Africa.

INTRODUCTION: Cryptococcal meningitis remains a significant contributor to AIDS-related mortality despite widened access to antiretroviral therapy. Cryptococcal antigen (CrAg) can be detected in the blood prior to development of meningitis. Development of highly sensitive and specific rapid diagnostic CrAg tests has helped facilitate the adoption of CrAg screening programs in 19 African countries. AREAS COVERED: The biological rationale for CrAg screening and the programmatic strategies for its implementation are reviewed. We describe the approach to the investigation of patients with cryptococcal antigenemia and the importance of lumbar puncture to identify individuals who may have cryptococcal meningitis in the absence of symptoms. The limitations of current treatment recommendations and the potential role of newly defined combination antifungal therapies are discussed. A literature review was conducted using a broad database search for cryptococcal antigen screening and related terms in published journal articles dating up to December 2019. Conference abstracts, publicly available guidelines, and project descriptions were also incorporated. EXPERT OPINION: As we learn more about the risks of cryptococcal antigenemia, it has become clear that the current management paradigm is inadequate. More intensive investigation and management are required to prevent the development of cryptococcal meningitis and reduce mortality associated with cryptococcal antigenemia.

False-positive galactomannan antigen testing in pulmonary nocardiosis.

Early diagnosis of invasive aspergillosis (IA) is facilitated by detection of galactomannan (GM) in serum and bronchoalveolar lavage fluid (BALF) using an enzyme-linked immunosorbent assay (ELISA). Although accurate, false positive results have been reported with these tests in numerous contexts. We report for the first time the occurrence of false positive GM ELISA due to nocardiosis, initially in a clinical sample of BALF from a patient with pulmonary nocardiosis, and subsequently corroborated by in vitro reactivity of 26% of tested isolates. Since patients at risk for IA are also at risk for nocardiosis, this finding has important clinical implications. LAY SUMMARY: Early diagnosis of aspergillosis has been facilitated by the routine use of antibody-based detection of galactomannan in various bodily fluids. We report for the first time the occurrence of false positive results of this assay in the context of nocardiosis.

IgG reactivity profile to Paracoccidioides spp. antigens in people with asymptomatic Paracoccidioidomycosis.

Introduction. Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides spp. As the disease is known to affect mostly men over 40 years old who previously worked handling soil, some cities of agricultural economy in endemic regions may have more cases of paracoccidioidal infection.Gap statement. The true frequency of PCM cannot be established in Brazil because it is not a disease of mandatory reporting. The detection of paracoccidioidal infection may assist in the planning of health services, in order to provide early detection of the disease and to prevent its worsening or even progression to death. In addition, little is described about sera reactivity with antigens from different species of Paracoccidiodes, especially P. lutzii.Aim. Current research was conducted in an inland municipality of southern Brazil, in order to assess infection rate within this endemic region of PCM disease.Methodology. ELISA was employed to evaluate 359 sera from random volunteers from Guarapuava, Paraná, Brazil, to detect IgG against cell-free antigens (CFA) from P. restrepiensis B339, P. americana LDR3 and P. lutzii LDR2. Confirmatory ELISA employed gp43 from B339. Reduction of cross-reactions was sought by treatment with sodium metaperiodate (SMP-CFA, SMP-gp43). Immunoblot was performed with 37 selected sera among those reactive in ELISA. Epidemiological profile was assessed by questionnaire.Results. ELISA reactivity was: CFA/SMP-CFA in general 37.3/17.8 %, B339 25.3/14.5 %, LDR3 24.5/1.4 %, LDR2 8.3/5.8 %; gp43/SMP-gp43 7.2/4.7 %. There were sera reactive with multiple CFAs. In immunoblot, five sera showed the same reaction profile with P. lutzii's antigens as PCM disease sera. Rural residence and soil-related professions were risk factors for paracoccidioidal infection.Conclusion. The low prevalence is in accordance with previous reports of lower PCM disease endemicity in Guarapuava than in other areas of Paraná. Although P. brasiliensis seems to be the prevalent strain of the region, 21 sera from people who only lived in Guarapuava reacted with P. lutzii LDR2. CFA-ELISA with whole antigens seems a good option for serological screening in epidemiological surveys.