Primers for clinical detection of Paracoccidioides brasiliensis

Standardization of Semi-Quantitative Dot Blotting Assay-Application in the Diagnosis, Follow-Up, and Relapse of Paracoccidioidomycosis

INTRODUCTION

This study standardized a semi-quantitative dot blotting assay (DB) and a quantitative real-time polymerase chain reaction (qPCR) to detect specific antibodies for Paracoccidioides brasiliensis and its DNA in PCM patients.

METHODOLOGY

We evaluated 42 confirmed PCM patients upon admission using a serological double agar gel immunodiffusion test (DID), DB, and molecular tests (qPCR in total blood). The control groups included 42 healthy individuals and 37 patients with other infectious diseases. The serological progress during treatment was evaluated in eight patients, and there was a relapse diagnosis in ten patients using the Pb B.339 strain antigen. The cut-off points for the serological tests were determined by a receiver operator characteristic curve.

RESULTS

The DB and DID tests showed similar accuracy, but the DB identified lower antibody concentrations. Cross-reactions were absent in the DB assay. In the relapse diagnoses, DB exhibited much higher sensitivity (90%) than DID (30%).

CONCLUSIONS

A DB assay is easier and faster than a DID test to be performed; DB and DID tests show the same accuracy, while blood qPCR is not recommended in the diagnosis at the time of admission; cross-reactions were not observed with other systemic diseases; DB and DID tests are useful for treatment monitoring PCM patients; and a DB assay is the choice for diagnosing relapse. These findings support the introduction of semi-quantitative DB assays in clinical laboratories.

Paracoccidioidomycosis: Current Status and Future Trends

Paracoccidioidomycosis (PCM), initially reported in 1908 in the city of São Paulo, Brazil, by Adolpho Lutz, is primarily a systemic and neglected tropical mycosis that may affect individuals with certain risk factors around Latin America, especially Brazil. Paracoccidioides brasiliensis sensu stricto, a classical thermodimorphic fungus associated with PCM, was long considered to represent a monotypic taxon. However, advances in molecular taxonomy revealed several cryptic species, including Paracoccidioides americana, P. restrepiensis, P. venezuelensis, and P. lutzii, that show a preference for skin and mucous membranes, lymph nodes, and respiratory organs but can also affect many other organs. The classical diagnosis of PCM benefits from direct microscopy culture-based, biochemical, and immunological assays in a general microbiology laboratory practice providing a generic identification of the agents. However, molecular assays should be employed to identify Paracoccidioides isolates to the species level, data that would be complemented by epidemiological investigations. From a clinical perspective, all probable and confirmed cases should be treated. The choice of treatment and its duration must be considered, along with the affected organs, process severity, history of previous treatment failure, possibility of administering oral medication, associated diseases, pregnancy, and patient compliance with the proposed treatment regimen. Nevertheless, even after appropriate treatment, there may be relapses, which generally occur 5 years after the apparent cure following treatment, and also, the mycosis may be confused with other diseases. This review provides a comprehensive and critical overview of the immunopathology, laboratory diagnosis, clinical aspects, and current treatment of PCM, highlighting current issues in the identification, treatment, and patient follow-up in light of recent Paracoccidioides species taxonomic developments.

Prevalence of pulmonary mycoses in smear-negative patients with suspected tuberculosis in the Brazilian Amazon

BACKGROUND

Pulmonary mycoses resemble clinically and radiologically chronic pulmonary tuberculosis. Studies describing the prevalence, etiology and clinical features of pulmonary mycosis are of crucial importance in the Brazilian Amazon.

AIMS

To estimate the frequency of pulmonary mycoses in smear-negative tuberculosis patients; to describe their demographic, epidemiological, and clinical characteristics; and to evaluate diagnostic methods.

METHODS

A cross-sectional study was conducted at two tuberculosis reference institutions in Amazonas, Brazil. We included 213 patients and collected clinical data, blood and induced sputum to perform serological, direct microscopy, microbiologic culture and PCR-based assays to identify infections caused by Aspergillus fumigatus, Paracoccidioides brasiliensis, Histoplasma capsulatum, Cryptococcus, and HIV. Chest computed tomography was also performed.

RESULTS

Pulmonary mycoses were diagnosed in 7% (15/213) of the cases, comprising ten aspergillosis cases, three cases of paracoccidioidomycosis and one case each of histoplasmosis and cryptococcosis. Among the patients with pulmonary mycoses, 86.7% were former tuberculosis patients. The most significant clinical characteristics associated with pulmonary mycoses were cavity-shaped lung injuries, prolonged chronic cough and hemoptysis.

CONCLUSIONS

Our study confirmed the high prevalence of pulmonary mycoses in smear-negative tuberculosis patients in the Brazilian Amazon.

Molecular Tools for Detection and Identification of Paracoccidioides Species: Current Status and Future Perspectives

Paracoccidioidomycosis (PCM) is a mycotic disease caused by the Paracoccidioides species, a group of thermally dimorphic fungi that grow in mycelial form at 25 °C and as budding yeasts when cultured at 37 °C or when parasitizing the host tissues. PCM occurs in a large area of Latin America, and the most critical regions of endemicity are in Brazil, Colombia, and Venezuela. The clinical diagnosis of PCM needs to be confirmed through laboratory tests. Although classical laboratory techniques provide valuable information due to the presence of pathognomonic forms of Paracoccidioides spp., nucleic acid-based diagnostics gradually are replacing or complementing culture-based, biochemical, and immunological assays in routine microbiology laboratory practice. Recently, taxonomic changes driven by whole-genomic sequencing of Paracoccidioides have highlighted the need to recognize species boundaries, which could better ascertain Paracoccidioides taxonomy. In this scenario, classical laboratory techniques do not have significant discriminatory power over cryptic agents. On the other hand, several PCR-based methods can detect polymorphisms in Paracoccidioides DNA and thus support species identification. This review is focused on the recent achievements in molecular diagnostics of paracoccidioidomycosis, including the main advantages and pitfalls related to each technique. We discuss these breakthroughs in light of taxonomic changes in the Paracoccidioides genus.

Metabolomics and Machine Learning Approaches Combined in Pursuit for More Accurate Paracoccidioidomycosis Diagnoses

Brazil and many other Latin American countries are areas of endemicity for different neglected diseases, and the fungal infection paracoccidioidomycosis (PCM) is one of them. Among the clinical manifestations, pneumopathy associated with skin and mucosal lesions is the most frequent. PCM definitive diagnosis depends on yeast microscopic visualization and immunological tests, but both present ambiguous results and difficulty in differentiating PCM from other fungal infections. This research has employed metabolomics analysis through high-resolution mass spectrometry to identify PCM biomarkers in serum samples in order to improve diagnosis for this debilitating disease. To upgrade the biomarker selection, machine learning approaches, using Random Forest classifiers, were combined with metabolomics data analysis. The proposed combination of these two analytical methods resulted in the identification of a set of 19 PCM biomarkers that show accuracy of 97.1%, specificity of 100%, and sensitivity of 94.1%. The obtained results are promising and present great potential to improve PCM definitive diagnosis and adequate pharmacological treatment, reducing the incidence of PCM sequelae and resulting in a better quality of life.IMPORTANCE Paracoccidioidomycosis (PCM) is a fungal infection typically found in Latin American countries, especially in Brazil. The identification of this disease is based on techniques that may fail sometimes. Intending to improve PCM detection in patient samples, this study used the combination of two of the newest technologies, artificial intelligence and metabolomics. This combination allowed PCM detection, independently of disease form, through identification of a set of molecules present in patients' blood. The great difference in this research was the ability to detect disease with better confidence than the routine methods employed today. Another important point is that among the molecules, it was possible to identify some indicators of contamination and other infection that might worsen patients' condition. Thus, the present work shows a great potential to improve PCM diagnosis and even disease management, considering the possibility to identify concomitant harmful factors.

Virulence factors of Paracoccidioides brasiliensis as therapeutic targets: a review

Paracoccidiodomycosis (PCM) is a systemic mycosis caused by the fungus Paracoccidioides brasiliensis and Paracoccidioides lutzii. The disease requires long and complicated treatment. The aim of this review is to address the fungal virulence factors that could be the target of the development of new drugs for PCM treatment. Virulence factors favoring the process of fungal infection and pathogenicity are considered as a microbial attribute associated with host susceptibility. P. brasiliensis has some known virulence factors which are 43 kDa glycoprotein (gp 43) which is an important fungal antigen, 70 kDa glycoprotein (gp 70), the carbohydrates constituting the fungal cell wall α-1,3, glucan and β-1,3-glucan, cell adhesion molecules and the presence of melanin pigments. The discovery and development of drugs that interact with these factors, such as inhibitors of β-1,3-glucan, reduced synthesis of gp 43, inhibitors of melanin production, is of great importance for the treatment of PCM. The study of virulence factors favors the understanding of pathogen-host relationships, aiming to evaluate the possibility of developing new therapeutic targets and mechanisms that these molecules play in the infectious process, favoring the design of a more specific treatment for this disease.

Paracoccidioidomycosis: Current Perspectives from Brazil

BACKGROUND

This review article summarizes and updates the knowledge on paracoccidioidomycosis. P lutzii and the cryptic species of P. brasiliensis and their geographical distribution in Latin America, explaining the difficulties observed in the serological diagnosis.

OBJECTIVES

Emphasis has been placed on some genetic factors as predisposing condition for paracoccidioidomycosis. Veterinary aspects were focused, showing the wide distribution of infection among animals. The cell-mediated immunity was better characterized, incorporating the recent findings.

METHODS

Serological methods for diagnosis were also compared for their parameters of accuracy, including the analysis of relapse.

RESULTS

Clinical forms have been better classified in order to include the pictures less frequently observesiod.

CONCLUSION

Itraconazole and the trimethoprim-sulfamethoxazole combination was compared regarding efficacy, effectiveness and safety, demonstrating that azole should be the first choice in the treatment of paracoccidioidomycosis.

Molecular diagnosis of invasive mycoses of the central nervous system

INTRODUCTION

In September 2012, the Centers for Disease Control and Prevention (CDC) began investigating an outbreak of fungal meningitis among patients who had received contaminated preservative-free methyl prednisolone acetate injections from the New England Compounding Center in Framingham, Massachusetts. Thousands of patients were potentially exposed to tainted corticosteroids, but establishing the diagnosis of fungal meningitis during the nationwide outbreak was difficult because little was known about the natural history of the disease. Areas covered: The challenges associated with this outbreak highlighted the need for rapid and reliable methodologies to assist in the diagnosis of invasive mycoses of the central nervous system (IMCNS), which may be devastating and difficult to treat. In this paper, we review the causative agents of these potentially-lethal infections, which include cryptococcal meningitis, cerebral aspergillosis, and hematogenous Candida meningoencephalitis. Expert commentary: While microscopy, culture, and histopathologic identification of fungal pathogens remain the gold standard for diagnosis, new platforms and species-specific assays have recently emerged, including lateral flow immunoassays (LFA), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and multiplex PCR in conjunction with magnetic resonance (MR) to potentially aid in the diagnosis of IMCNS.

Molecular diagnosis of infectious diseases using cytological specimens

Pathologists have an important role in the diagnosis of infectious disease (ID). In many cases, a definitive diagnosis can be made using cytopathology alone. However, several ancillary techniques can be used on cytological material to reach a specific diagnosis by identifying the causative agent and consequently defining the management of the patient. This review aims to present the effectiveness of the application of molecular studies on cytological material to diagnose IDs and discuss the advantages and disadvantages of the various molecular techniques according to the type of cytological specimen and the infectious agents.

Paracoccidioides-host Interaction: An Overview on Recent Advances in the Paracoccidioidomycosis

Paracoccidioides brasiliensis and P. lutzii are etiologic agents of paracoccidioidomycosis (PCM), an important endemic mycosis in Latin America. During its evolution, these fungi have developed characteristics and mechanisms that allow their growth in adverse conditions within their host through which they efficiently cause disease. This process is multi-factorial and involves host-pathogen interactions (adaptation, adhesion, and invasion), as well as fungal virulence and host immune response. In this review, we demonstrated the glycoproteins and polysaccharides network, which composes the cell wall of Paracoccidioides spp. These are important for the change of conidia or mycelial (26°C) to parasitic yeast (37°C). The morphological switch, a mechanism for the pathogen to adapt and thrive inside the host, is obligatory for the establishment of the infection and seems to be related to pathogenicity. For these fungi, one of the most important steps during the interaction with the host is the adhesion. Cell surface proteins called adhesins, responsible for the first contact with host cells, contribute to host colonization and invasion by mediating this process. These fungi also present the capacity to form biofilm and through which they may evade the host's immune system. During infection, Paracoccidioides spp. can interact with different host cell types and has the ability to modulate the host's adaptive and/or innate immune response. In addition, it participates and interferes in the coagulation system and phenomena like cytoskeletal rearrangement and apoptosis. In recent years, Paracoccidioides spp. have had their endemic areas expanding in correlation with the expansion of agriculture. In response, several studies were developed to understand the infection using in vitro and in vivo systems, including alternative non-mammal models. Moreover, new advances were made in treating these infections using both well-established and new antifungal agents. These included natural and/or derivate synthetic substances as well as vaccines, peptides, and anti-adhesins sera. Because of all the advances in the PCM study, this review has the objective to summarize all of the recent discoveries on Paracoccidioides-host interaction, with particular emphasis on fungi surface proteins (molecules that play a fundamental role in the adhesion and/or dissemination of the fungi to host-cells), as well as advances in the treatment of PCM with new and well-established antifungal agents and approaches.

Prevalence and serological diagnosis of relapse in paracoccidioidomycosis patients

A review of 400 clinical records of paracoccidioidomycosis (PCM) patients, 93 with the acute/subacute (AF) and 307 with the chronic form (CF), attended from 1977 to 2011, selected as to the schedule of release for study by the Office of Medical Records at the University Hospital of the Faculdade de Medicina de Botucatu-São Paulo State University--UNESP, was performed to detect cases in relapse. The control of cure was performed by clinical and serological evaluation using the double agar gel immunodiffusion test (DID). In the diagnosis of relapse, DID, enzyme-linked immunosorbent assay (ELISA) and immunoblotting assay (IBgp70 and IBgp43) were evaluated. Out of 400 patients, 21 (5.2%) went through relapse, 18 of them were male and 3 were female, 6∶1 male/female ratio. Out of the 21 patients in relapse, 15 (4.8%) showed the CF, and 6 (6.4%) the AF (p>0.05). The sensitivity of DID and ELISA before treatment was the same (76.1%). DID presented higher sensitivity in pre-treatment (80%) than at relapse (45%; p = 0.017), while ELISA showed the same sensitivity (80% vs 65%; p = 0.125). The serological methods for identifying PCM patients in relapse showed low rates of sensitivity, from 12.5% in IBgp70 to 65.0% in IBgp43 identification and 68.8% in ELISA. The sensitivity of ELISA in diagnosing PCM relapse showed a strong tendency to be higher than DID (p = 0.06) and is equal to IBgp43 (p = 0.11). In sum, prevalence of relapse was not high in PCM patients whose treatment duration was based on immunological parameters. However, the used methods for serological diagnosis present low sensitivity. While more accurate serological methods are not available, we pay special attention to the mycological and histopathological diagnosis of PCM relapse. Hence, direct mycological, cytopathological, and histopathological examinations and isolation in culture for P. brasiliensis must be appropriately and routinely performed when the hypothesis of relapse is considered.

Important aspects of oral paracoccidioidomycosis--a literature review

Paracoccidioidomycosis is a deep mycosis endemic to Latin America, with considerable morbidity and mortality. It is caused by the dimorphic fungus Paracoccidioides brasiliensis, which affects, among other organs in the human body, the oral cavity. Fungus virulence and immunocompetence of the host determine the establishment of infection or active disease, whose severity and clinical behaviour depend mostly on the cellular immune response of the host. Often, oral lesions constitute the first sign and site of confirmation of diagnosis, which in most cases is delayed. The success of the treatment depends on early and correct diagnosis, as well as on the patient's adherence to the drug therapy.

[Mycoses in Venezuela: Working Groups in Mycology reported cases (1984-2010)]

BACKGROUND

In 1984 the Venezuelan Work Groups in Mycology (VWGM) were created introducing an innovative approach to the study of the mycoses in Venezuela.

AIM

To study the occurrence of the mycoses in Venezuela.

METHODS

Review the reported cases of mycoses by the newsletter Boletín Informativo Las Micosis en Venezuela (VWGM) from 1984 to 2010.

RESULTS

The data collected showed 36,968 reported cases of superficial mycoses, 1,989 of deep systemic cases, and 822 of localized mycoses. Pityriasis dermatophytosis was the most common superficial infection, and paracoccidioidomycosis and histoplasmosis the most frequent deep systemic infection. Chromoblastomycosis was the most frequently diagnosed subcutaneous infection. The data provided showed the distribution by geographical area for each of the fungal infections studied, which may help to establish the endemic areas.

DISCUSSION

Superficial mycosis is a public health problem due to its high morbidity and is probably responsible for some of the outbreaks in high-risk groups. Paracoccidioidomycosis and histoplasmosis were reported more often, which agrees with earlier reports prior to the formation of the VWGM. Cases of sporotrichosis and chromoblastomycosis in Venezuela can be considered unique due to the high number of cases. This study highlights the contribution of the VWGM to the behavior of the mycoses in Venezuela, its incidence, prevalence, and the recognition of these infections as a problem of public health importance. The VWGM should keep working in this endeavor, not only reporting new cases, but also unifying the clinical and epidemiological criteria, in order to properly monitor the evolving epidemiological changes reported in these types of infections.

A semi-nested PCR assay for molecular detection of Paracoccidioides brasiliensis in tissue samples

INTRODUCTION

Paracoccidioidomycosis is a systemic infection caused by Paracoccidioides brasiliensis.

METHODS

In this study, a semi-nested PCR for paracoccidioidomycosis diagnosis was developed. The primers ITS1 and ITS4 were used in the first reaction, while the primers MJ03 and ITS1 primer were used in the second reaction. The semi-nested PCR was used to investigate biopsies of five patients with oral lesions that resembled paracoccidioidomycosis.

RESULTS

The semi-nested PCR was positive for four samples and negative for a sample from a patient later diagnosed with leishmaniasis.

CONCLUSIONS

The new semi-nested PCR describe is useful for paracoccidioidomycosis diagnosis.

Histoplasmosis and paracoccidioidomycosis in a non-endemic area: a review of cases and diagnosis

BACKGROUND

Histoplasmosis and paracoccidioidomycosis (PCM) have increased in Spain in recent years, due firstly to the migration from endemic regions and secondly to travelers returning from these regions. In non-endemic areas, diagnosis of both diseases is hampered by the lack of experience, long silent periods, and the resemblance to other diseases such as tuberculosis and sarcoidosis.

METHODS

A total of 39 cases of imported histoplasmosis and 6 cases of PCM diagnosed in the Spanish Mycology Reference Laboratory since 2006 were analyzed. Microbiological diagnosis was performed using classical methods and also a specific real-time polymerase chain reaction (RT-PCR) assay for each microorganism.

RESULTS

We had 9 cases of probable histoplasmosis in travelers and 30 cases in immigrants, 29 of whom were defined as proven. Paracoccidioidomycosis (PCM) cases were either immigrants or people who had lived for a long period of time in endemic regions, all of whom were classified as proven cases. Cultures showed a good sensitivity in detecting Histoplasma capsulatum in immigrants with proven histoplasmosis (73%); however, growth was very slow. The fungus was never recovered in traveler patients. Paracoccidioides brasiliensis was isolated in a culture only in one case of the proven PCM. Serological methods were not very reliable in immunocompromised patients with histoplasmosis (40%). A PCR-based technique for histoplasmosis detected 55.5% of the cases in travelers (probable cases) and 89% of the cases in immigrants (proven). The PCR method for PCM detected 100% of the cases.

CONCLUSIONS

These kinds of mycoses are increasingly frequent in non-endemic areas, and newer and faster techniques should be used to reach an early diagnosis. The RT-PCR techniques developed appear to be sensitive, specific, and fast and could be helpful to detect those mycoses. However, it is also essential that physicians perform differential diagnosis in individuals coming from endemic areas.

Experimental medical mycological research in Latin America - a 2000-2009 overview

An overview of current trends in Latin American Experimental Medical Mycological research since the beginning of the 21(st) century is done (search from January 2000 to December 2009). Using the PubMed and LILACS databases, the authors have chosen publications on medically important fungi which, according to our opinion, are the most relevant because of their novelty, interest, and international impact, based on research made entirely in the Latin American region or as part of collaborative efforts with laboratories elsewhere. In this way, the following areas are discussed: 1) molecular identification of fungal pathogens; 2) molecular and clinical epidemiology on fungal pathogens of prevalence in the region; 3) cell biology; 4) transcriptome, genome, molecular taxonomy and phylogeny; 5) immunology; 6) vaccines; 7) new and experimental antifungals.

Immunological basis for the gender differences in murine Paracoccidioides brasiliensis infection

This study aimed to investigate the immunological mechanisms involved in the gender distinct incidence of paracoccidioidomycosis (pcm), an endemic systemic mycosis in Latin America, which is at least 10 times more frequent in men than in women. Then, we compared the immune response of male and female mice to Paracoccidioides brasiliensis infection, as well as the influence in the gender differences exerted by paracoccin, a P. brasiliensis component with carbohydrate recognition property. High production of Th1 cytokines and T-bet expression have been detected in the paracoccin stimulated cultures of spleen cells from infected female mice. In contrast, in similar experimental conditions, cells from infected males produced higher levels of the Th2 cytokines and expressed GATA-3. Macrophages from male and female mice when stimulated with paracoccin displayed similar phagocytic capability, while fungicidal activity was two times more efficiently performed by macrophages from female mice, a fact that was associated with 50% higher levels of nitric oxide production. In order to evaluate the role of sexual hormones in the observed gender distinction, we have utilized mice that have been submitted to gonadectomy followed by inverse hormonal reconstitution. Spleen cells derived from castrated males reconstituted with estradiol have produced higher levels of IFN-γ (1291±15 pg/mL) and lower levels of IL-10 (494±38 pg/mL), than normal male in response to paracoccin stimulus. In contrast, spleen cells from castrated female mice that had been treated with testosterone produced more IL-10 (1284±36 pg/mL) and less IFN-γ (587±14 pg/mL) than cells from normal female. In conclusion, our results reveal that the sexual hormones had a profound effect on the biology of immune cells, and estradiol favours protective responses to P. brasiliensis infection. In addition, fungal components, such as paracoccin, may provide additional support to the gender dimorphic immunity that marks P. brasiliensis infection.

Lack of galectin-3 drives response to Paracoccidioides brasiliensis toward a Th2-biased immunity

There is recent evidence that galectin-3 participates in immunity to infections, mostly by tuning cytokine production. We studied the balance of Th1/Th2 responses to P. brasiliensis experimental infection in the absence of galectin-3. The intermediate resistance to the fungal infection presented by C57BL/6 mice, associated with the development of a mixed type of immunity, was replaced with susceptibility to infection and a Th2-polarized immune response, in galectin-3-deficient (gal3^−/−) mice. Such a response was associated with defective inflammatory and delayed type hypersensitivity (DTH) reactions, high IL-4 and GATA-3 expression and low nitric oxide production in the organs of infected animals. Gal3^−/− macrophages exhibited higher TLR2 transcript levels and IL-10 production compared to wild-type macrophages after stimulation with P. brasiliensis antigens. We hypothesize that, during an in vivo P. brasiliensis infection, galectin-3 exerts its tuning role on immunity by interfering with the generation of regulatory macrophages, thus hindering the consequent Th2-polarized type of response.

Paracoccidioides brasiliensis: chemical and molecular tools for research on cell walls, antifungals, diagnosis, taxonomy

Paracoccidioides brasiliensis is a dimorphic fungus, a causative agent of paracoccidioidomycosis, one of the most frequent systemic mycoses that affect the rural population in Latin America, only geographical region in which this fungus is to be found. In this work, we discuss matters related to (a) cell wall studies based on the cloning and analysis of genes involved in the synthesis of cell wall components, and their possible roles in virulence and dimorphism in P. brasiliensis, (b) molecular taxonomy and the molecular classification of P. brasiliensis as an Ascomycete belonging in the Order Onygenales, (c) phylogeny of P. brasiliensis and the possible existence of cryptic species within the genus Paracoccidioides, and (d) new experimental antifungal drugs such as azasterols or sterol hydrazones, compounds that affect the activity of delta 24(28) sterol methyl reductase (SMR) and/or delta (24)-sterol methyl transferase (SMT), and (e) specific primers for the molecular detection of P. brasiliensis in vitro and in clinical samples.