Medical and Experimental Mycology Unit

Medellín, Colombia

Medical and Experimental Mycology Unit

Medellín, Colombia
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PubMed | Fundacion Institute Inmunologia Of Colombia Fidic, Medical and Experimental Mycology Unit, Pontifical Xavierian University and El Rosario University
Type: | Journal: BMC microbiology | Year: 2015

Candida species are the most frequently found fungal pathogens causing nosocomial disease in a hospital setting. Such species must be correctly identified to ensure that appropriate control measures are taken and that suitable treatment is given for each species. Candida albicans is causing most fungal disease burden worldwide; the challenge lies in differentiating it from emerging atypical, minor and related species such as Candida dubliniensis and Candida africana. The purpose of this study was to compare identification based on MALDI-TOF MS to standard identification systems using a set of nosocomial isolates.Eleven nosocomial samples were collected from 6 third-level hospitals in Bogot, Colombia. All the samples were identified by combining MALDI-TOF MS with morphological characters, carbohydrate assimilation and molecular markers (D1/D2 and HWP1).The present work describes the first collection of atypical Colombian Candida clinical isolates; these were identified as Candida albicans/Candida africana by their MALDI-TOF MS profile. Phenotypical characteristics showed that they were unable to produce chlamydospores, assimilate trehalose, glucosamine, N- acetyl-glucosamine and barely grew at 42C, as would be expected for Candida africana. The molecular identification of the D1/D2 region of large subunit ribosomal RNA and HWP1 hyphal cell wall protein 1 sequences from these isolates was consistent with those for Candida albicans. The mass spectra obtained by MALDI-TOF MS were analysed by multi-dimensional scaling (MDS) and cluster analysis, differences being revealed between Candida albicans, Candida africana, Candida dubliniensis reference spectra and two clinical isolate groups which clustered according to the clinical setting, one of them being clearly related to C. albicans.This study highlights the importance of using MALDI-TOF MS in combination with morphology, substrate assimilation and molecular markers for characterising Candida albicans-related and atypical C. albicans species, thereby overcoming conventional identification methods. This is the first report of hospital-obtained isolates of this type in Colombia; the approach followed might be useful for gathering knowledge regarding local epidemiology which could, in turn, have an impact on clinical management. The findings highlight the complexity of distinguishing between typical and atypical Candida albicans isolates in hospitals.


Tamayo D.,Molecular and Cell Biology Unit | Tamayo D.,Major College of Antioquia | Hernandez O.,Molecular and Cell Biology Unit | Hernandez O.,Major College of Antioquia | And 4 more authors.
Memorias do Instituto Oswaldo Cruz | Year: 2013

The infectious process starts with an initial contact between pathogen and host. We have previously demonstrated that Paracoccidioides brasiliensis conidia interact with plasma proteins including fibrinogen, which is considered the major component of the coagulation system. In this study, we evaluated the in vitro capacity of P. brasiliensis conidia to aggregate with plasma proteins and compounds involved in the coagulation system. We assessed the aggregation of P. brasiliensis conidia after incubation with human serum or plasma in the presence or absence of anticoagulants, extracellular matrix (ECM) proteins, metabolic and protein inhibitors, monosaccharides and other compounds. Additionally, prothrombin and partial thromboplastin times were determined after the interaction of P. brasiliensis conidia with human plasma. ECM proteins, monosaccharides and human plasma significantly induced P. brasiliensis conidial aggregation; however, anticoagulants and metabolic and protein inhibitors diminished the aggregation process. The extrinsic coagulation pathway was not affected by the interaction between P. brasiliensis conidia and plasma proteins, while the intrinsic pathway was markedly altered. These results indicate that P. brasili-ensis conidia interact with proteins involved in the coagulation system. This interaction may play an important role in the initial inflammatory response, as well as fungal disease progression caused by P. brasiliensis dissemination.


Puerta-Arias J.D.,Medical and Experimental Mycology Unit | Pino-Tamayo P.A.,Medical and Experimental Mycology Unit | Arango J.C.,Medical and Experimental Mycology Unit | Arango J.C.,University of Antioquia | Gonzalez A.,University of Antioquia
PLoS ONE | Year: 2016

Chronic stages of paracoccidioidomycosis (PCM) are characterized by granulomatous lesions which promote the development of pulmonary fibrosis leading to the loss of respiratory function in 50% of patients; in addition, it has been observed that neutrophils predominate during these chronic stages of P. brasiliensis infection. The goal of this study was to evaluate the role of the neutrophil during the chronic stages of experimental pulmonary PCM and during the fibrosis development and tissue repair using a monoclonal specific to this phagocytic cell. Male BALB/c mice were inoculated intranasally with 1.5x106 P. brasiliensis yeast cells. A monoclonal antibody specific to neutrophils was administered at 4 weeks post-inoculation followed by doses every 48h during two weeks. Mice were sacrificed at 8 and 12 weeks post-inoculation to assess cellularity, fungal load, cytokine/chemokine levels, histopathological analysis, collagen and expression of genes related to fibrosis development. Depletion of neutrophils was associated with a significant decrease in the number of eosinophils, dendritic cells, B cells, CD4-T cells, MDSCs and Treg cells, fungal load and levels of most of the pro-inflammatory cytokines/chemokines evaluated, including IL-17, TNF-α and TGF-β1. Recovery of lung architecture was also associated with reduced levels of collagen, high expression of TGF-β3, matrix metalloproteinase (MMP)-12 and -14, and decreased expression of tissue inhibitor metalloproteinase (TIMP)-2, and MMP-8. Depletion of neutrophils might attenuate lung fibrosis and inflammation through down-regulating TGF-β1, TNF-α, IL-17, MMP-8 and TIMP-2. These results suggest that neutrophil could be considered as a therapeutic target in pulmonary fibrosis induced by P. brasiliensis. © 2016 Puerta-Arias et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Zuluaga A.,Medical and Experimental Mycology Unit | Ospina-Medina J.,University of Antioquia | Castano-Gallego I.,University of Antioquia | Arango K.,Medical and Experimental Mycology Unit | Gonzalez A.,University of Antioquia
Diagnostic Microbiology and Infectious Disease | Year: 2015

Fungal rhinosinusitis (FRS) is one of the most important rhinosinusoidal disorders, which involves a variety of etiological agents. We carried out a study to determine the frequency of fungal agents in sinus samples from patients with clinically suspected rhinosinusitis (RS). A total of 205 clinical samples were assessed from 174 patients with clinically suspected RS, of which 48 were positive for microscopic examination and culture, 47 were positive for direct examination but negative by culture, 4 were negative for direct examination but positive by culture, and 106 were negative for both methodologies. The main fungal agents isolated were Aspergillus spp. (32.7%), followed by Schizophyllum commune (28.8%). Sensitivity and specificity of the direct examination were 92.3% and 69.3%, respectively, and concordance between the direct examination and culture was 48.4%. This study indicated that both Aspergillus and S. commune appear to be the most important agents involved in the development of FRS. © 2015 Elsevier Inc.


Nucci M.,Federal University of Rio de Janeiro | Queiroz-Telles F.,Federal University of Paraná | Tobon A.M.,Medical and Experimental Mycology Unit | Restrepo A.,Medical and Experimental Mycology Unit | Colombo A.L.,University of Sao Paulo
Clinical Infectious Diseases | Year: 2010

This review discusses the epidemiology of the most clinically relevant opportunistic fungal infections in Latin America, including candidiasis, cryptococcosis, trichosporonosis, aspergillosis, and fusariosis. The epidemiologic features, including incidence, of some of these mycoses are markedly different in Latin America than they are in other parts of the world. The most consistent epidemiologic data are available for candidemia, with a large prospective study in Brazil reporting an incidence that is 3- to 15-fold higher than that reported in studies from North America and Europe. Species distribution also differs: in Latin America, the most common Candida species (other than Candida albicans) causing bloodstream infections are Candida parapsilosis or Candida tropicalis, rather than Candida glabrata. © 2010 by the Infectious Diseases Society of America.


Lopes L.C.L.,Yeshiva University | Lopes L.C.L.,Federal University of Rio de Janeiro | Guimaraes A.J.,Yeshiva University | De Cerqueira M.D.,Yeshiva University | And 3 more authors.
Clinical and Vaccine Immunology | Year: 2010

Monoclonal antibodies to Histoplasma capsulatum can modify pathogenesis. We now show that monoclonal antibody H1C to a 70-kDa antigen increases intracellular fungal growth and reduces macrophage nitric oxide release but has no effect on fungal burden or survival in murine infection. This further demonstrates the complexities of host-pathogen interactions. Copyright © 2010, American Society for Microbiology. All Rights Reserved.


Restrepo A.,Medical and Experimental Mycology Unit | Cano L.E.,Medical and Experimental Mycology Unit | Cano L.E.,University of Antioquia | Gonzalez A.,University of Antioquia
Revista do Instituto de Medicina Tropical de Sao Paulo | Year: 2015

Research on Paracoccidioides brasiliensis has centered in the yeast cell probably because of the lack of distinctive features in the mycelium. In 1942 and for the first time, lateral conidia were noticed in the fungus’ hyphae. Later on, Brazilian, Venezuelan and Argentinean researchers described “aleurias” when the fungus was grown in natural substrates. In 1970 authors became interested in the conidia and were able to obtain them in large numbers and treat them as individual units. Their shape and size were defined and the presence of all the elements of a competent eukaryotic cell were demonstrated. Conidia exhibited thermal dimorphism and, additionally, when given intranasally to BALB/c male mice, they converted into yeasts in the lungs and produce progressive pulmonary lesions with further dissemination to other organs. Studies on the phagocyte-conidia interaction were revealing and showed that these versatile structures allow a better understanding of the host- P. brasiliensis interactions. © 2015, Instituto de Medicina Tropical de Sao Paulo. All rights reserved.


Uran M.E.,Medical and Experimental Mycology Unit | Uran M.E.,Pontifical Bolivarian University | Nosanchuk J.D.,Yeshiva University | Restrepo A.,Medical and Experimental Mycology Unit | And 6 more authors.
Clinical and Vaccine Immunology | Year: 2011

Several cell wall constituents, including melanins or melanin-like compounds, have been implicated in the pathogenesis of a wide variety of microbial diseases caused by diverse species of pathogenic bacteria, fungi, and helminthes. Among these microorganisms, the dimorphic fungal pathogen Paracoccidioides brasiliensis produces melanin in its conidial and yeast forms. In the present study, melanin particles from P. brasiliensis were injected into BALB/c mice in order to produce monoclonal antibodies (MAbs). We identified five immunoglobulin G1 (IgG1) κ-chain and four IgM melanin-binding MAbs. The five IgG1 κ-chain isotypes are the first melanin-binding IgG MAbs ever reported. The nine MAbs labeled P. brasiliensis conidia and yeast cells both in vitro and in pulmonary tissues. The MAbs cross-reacted with melanin-like purified particles from other fungi and also with commercial melanins, such as synthetic and Sepia officinalis melanin. Melanization during paracoccidioidomycosis (PCM) was also further supported by the detection of IgG antibodies reactive to melanin from P. brasiliensis conidia and yeast in sera and bronchoalveolar lavage fluids from P. brasiliensis-infected mice, as well as in sera from human patients with PCM. Serum specimens from patients with other mycoses were also tested for melanin-binding antibodies by enzyme-linked immunosorbent assay, and cross-reactivities were detected for melanin particles from different fungal sources. These results suggest that melanin from P. brasiliensis is an immunologically active fungal structure that activates a strong IgG humoral response in humans and mice. Copyright © 2011, American Society for Microbiology. All Rights Reserved.


Pino-Tamayo P.A.,Medical and Experimental Mycology Unit | Puerta-Arias J.D.,Medical and Experimental Mycology Unit | Lopera D.,Medical and Experimental Mycology Unit | Uran-Jimenez M.E.,Medical and Experimental Mycology Unit | Gonzalez A.,University of Antioquia
Mediators of Inflammation | Year: 2016

Neutrophils predominate during the acute phase of the Paracoccidioides brasiliensis infection. Herein, we determined the role of the neutrophil during the early stages of experimental pulmonary paracoccidioidomycosis using a monoclonal antibody (mAb) specific for neutrophils. Male BALB/c mice were inoculated intranasally with 1.5 × 106 or 2 × 106 P. brasiliensis yeast cells. The mAb was administered 24 h before infection, followed by doses every 48 h until mice were sacrificed. Survival time was evaluated and mice were sacrificed at 48 h and 96 h after inoculation to assess cellularity, fungal load, cytokine/chemokine levels, and histopathological analysis. Neutrophils from mAb-treated mice were efficiently depleted (99.04%). Eighty percent of the mice treated with the mAb and infected with 1.5 × 106 yeast cells died during the first two weeks after infection. When mice were treated and infected with 2 × 106 yeast cells, 100% of them succumbed by the first week after infection. During the acute inflammatory response significant increases in numbers of eosinophils, fungal load and levels of proinflammatory cytokines/chemokines were observed in the mAb-treated mice. We also confirmed that neutrophils are an important source of IFN-γ and IL-17. These results indicate that neutrophils are essential for protection as well as being important for regulating the early inflammatory immune response in experimental pulmonary paracoccidioidomycosis. © 2016 Paula Andrea Pino-Tamayo et al.


PubMed | Medical and Experimental Mycology Unit and University of Antioquia
Type: | Journal: Mediators of inflammation | Year: 2016

Neutrophils predominate during the acute phase of the Paracoccidioides brasiliensis infection. Herein, we determined the role of the neutrophil during the early stages of experimental pulmonary paracoccidioidomycosis using a monoclonal antibody (mAb) specific for neutrophils. Male BALB/c mice were inoculated intranasally with 1.5 10(6) or 2 10(6) P. brasiliensis yeast cells. The mAb was administered 24h before infection, followed by doses every 48h until mice were sacrificed. Survival time was evaluated and mice were sacrificed at 48h and 96h after inoculation to assess cellularity, fungal load, cytokine/chemokine levels, and histopathological analysis. Neutrophils from mAb-treated mice were efficiently depleted (99.04%). Eighty percent of the mice treated with the mAb and infected with 1.5 10(6) yeast cells died during the first two weeks after infection. When mice were treated and infected with 2 10(6) yeast cells, 100% of them succumbed by the first week after infection. During the acute inflammatory response significant increases in numbers of eosinophils, fungal load and levels of proinflammatory cytokines/chemokines were observed in the mAb-treated mice. We also confirmed that neutrophils are an important source of IFN- and IL-17. These results indicate that neutrophils are essential for protection as well as being important for regulating the early inflammatory immune response in experimental pulmonary paracoccidioidomycosis.

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