Paracoccidioides brasiliensis habitat: far beyond armadillo burrows?

Paracoccidioides spp. isolation from environmental samples is rare and hardly reproducible. Molecular techniques have facilitated the fungal detection. However, it can be still difficult. Some strategies to enhance the capacity of DNA detection have been adopted, including the analysis of soil samples belonging to the habitat of animals from which Paracoccidioides spp. have already been isolated, notably armadillo burrows. To date, the detection of Paracoccidioides spp. has not yet been reported from outbreak hotspots. Clusters and outbreaks of acute paracoccidioidomycosis (PCM), usually a more severe clinical form, have currently occurred in urban areas being associated to climate changes, deforestation, and great constructions. These occurrences potentially signalise the fungus' environmental niche, a riddle not yet solved. The authors performed an environmental investigation in a deeply disturbed area, after a highway construction in Rio de Janeiro, Brazil, where a recent outbreak of acute PCM occurred. Specific DNA sequences of Paracoccidioides brasiliensis were detected in shallow soil samples around the highway, reinforcing the association between the road construction and this PCM outbreak.

Distinct chitinases are expressed during various growth phases of the human pathogen Paracoccidioides brasiliensis

The aim of this work was the partial purification and subsequent evaluation of chitinase expression during the various growth phases of Paracoccidioides brasiliensis. Initially, PbCTS1r was expressed as a recombinant protein and displayed enzymatic activity against 4-MU-[N-acetylglucosamine (GlcNAc)]3 and 4-MU-(GlcNAc)2. Two proteins, 45 kDa and 39 kDa in size, were partially purified from P. brasiliensis yeast crude extract using cation-exchange chromatography coupled with HPLC and were characterised as PbCTS1 and PbCTS2, respectively. Anti-PbCTS1r antibody recognised two proteins in the crude extracts of yeast and the transitional stage between mycelial and yeast phases. In crude extracts of mycelium, only the 45 kDa protein was detected. However, quantitative real-time polymerase chain reaction led to the detection of small quantities of Pbcts2 transcript in the mycelial phase. In the yeast cell wall extract, only the 39 kDa protein was detected. Moreover, both proteins were secreted by the yeast parasitic phase, suggesting that these proteins participate in the modulation of the fungal environment. Phylogenetic analysis of the predicted PbCTS1 and PbCTS2 proteins indicated that they code for distinct chitinases in P. brasiliensis. During evolution, P. brasiliensis could have acquired the paralogues Pbcts1 and Pbcts2 for growth and survival in diverse environments in both saprophytic and parasitic phases.

Interleukin-15 augments oxidative metabolism and fungicidal activity of human monocytes against Paracoccidioides brasiliensis

Interleukin (IL)-15 is a pleiotropic cytokine that regulates the proliferation and survival of many cell types. IL-15 is produced by monocytes and macrophages against infectious agents and plays a pivotal role in innate and adaptive immune responses. This study analyzed the effect of IL-15 on fungicidal activity, oxidative metabolism and cytokine production by human monocytes challenged in vitro with Paracoccidioides brasiliensis (Pb18), the agent of paracoccidioidomycosis. Peripheral blood monocytes were pre-incubated with IL-15 and then challenged with Pb18. Fungicidal activity was assessed by viable fungi recovery from cultures after plating on brain-heart infusion-agar. Superoxide anion (O2-), hydrogen peroxide (H2O2), tumour necrosis factor-alpha (TNF-α), IL-6, IL-15 and IL-10 production by monocytes were also determined. IL-15 enhanced fungicidal activity against Pb18 in a dose-dependent pattern. This effect was abrogated by addition of anti-IL-15 monoclonal antibody. A significant stimulatory effect of IL-15 on O2- and H2O2 release suggests that fungicidal activity was dependent on the activation of oxidative metabolism. Pre-treatment of monocytes with IL-15 induced significantly higher levels of TNF-α, IL-10 and IL-15 production by cells challenged with the fungus. These results suggest a modulatory effect of IL-15 on pro and anti-inflammatory cytokine production, oxidative metabolism and fungicidal activity of monocytes during Pb18 infection.

Lysozyme plays a dual role against the dimorphic fungus Paracoccidioides brasiliensis / A lisozima desempenha um papel duplo contra o fungo dimórfico Paracoccidioides brasiliensis

In order to determine the role of lysozyme, an antimicrobial peptide belonging to the innate immune system, against the dimorphic fungus Paracoccidioides brasiliensis, co-cultures of the MH-S murine alveolar macrophages cell line with P. brasiliensis conidia were done; assays to evaluate the effect of physiological and inflammatory concentrations of lysozyme directly on the fungus life cycle were also undertaken. We observed that TNF-α-activated macrophages significantly inhibited the conidia to yeast transition (p = 0.0043) and exerted an important fungicidal effect (p = 0.0044), killing 27 percent more fungal propagules in comparison with controls. Nonetheless, after adding a selective inhibitor of lysozyme, the fungicidal effect was reverted. When P. brasiliensis propagules were exposed directly to different concentrations of lysozyme, a dual effect was observed. Physiologic concentrations of the enzyme facilitated the conidia-to-yeast transition process (p < 0.05). On the contrary, inflammatory concentrations impaired the normal temperature-dependant fungal transition (p < 0.0001). When yeast cells were exposed to lysozyme, irrespective of concentration, the multiple-budding ability was badly impaired (p < 0.0001). In addition, ultra-structural changes such as subcellular degradation, fusion of lipid vacuoles, lamellar structures and interruption of the fibrilar layer were observed in lysozyme exposed conidia. These results suggest that lysozyme appears to exert a dual role as part of the anti-P. brasiliensis defense mechanisms.

Com a finalidade de determinar o papel da lisozima, um peptídeo antimicrobiano que pertence ao sistema imune inato, contra o fungo dimórfico Paracoccidioides brasiliensis, foram feitas co-culturas de uma linha de macrófagos alveolares murinos (MH-S) com as conídias do fungo na presença ou não do TNF-α e/ou um inibidor da lisozima; também foram feitos ensaios que avaliaram o efeito das concentrações fisiológicas e inflamatórias de lisozima diretamente sobre o ciclo de vida do fungo. Observamos que os macrófagos ativados com a citoquina tiveram um efeito significativo na inibição da transição conídia/levedura (p = 0,0043) e exerceram um efeito fungicida importante (p = 0,0044), matando mais de 27 por cento das propágulas do fungo em comparação com os macrófagos não ativados. No entanto, após ser o inibidor seletivo da lisozima adicionado, o efeito fungicida foi revertido. Quando os propágulos do fungo foram expostos diretamente a diferentes concentrações da lisozima, um duplo efeito foi observado. Assim, as concentrações fisiológicas da enzima facilitaram o processo de transição conídia-levedura (p < 0,05). Contrariamente, as concentrações inflamatórias prejudicaram a transição fúngica (p < 0,0001). Quando as leveduras foram expostas a qualquer concentração de lisozima, sua capacidade de multi-brotação foi gravemente prejudicada (p < 0,0001). Além disso, mudanças ultra-estruturais, como a sub degradação, a fusão dos vacúolos dos lípidos, estruturas lamelares e interrupção da camada fibrilar foram observadas em conídios expostos à lisozima. Estes resultados sugerem que a lisozima poderia exercer um duplo papel no mecanismo antifúngico contra P. brasiliensis.

Determinación de un medio de cultivo apropiado para acelerar el crecimiento de paracoccidioides brasiliensis / Determination of an appropriate culture medium to accelerate the growth of paracoccidioides brasiliensis

A pesar de los avances de la tecnología en los últimos años, en una infección micótica la "prueba de oro" para realizar el diagnóstico definitivo, es el aislamiento del agente causal mediante la práctica del cultivo de una muestra clínica; por lo que a través de los años han sido elaborados numerosos medios de cultivo, en los cuales se han utilizado desde sustancias naturales, hasta otras artificiales de composición más compleja. El problema más importante al cual se enfrentan los laboratorios de micología médica, es que los hongos productores de micosis profundas en Venezuela, tienen la propiedad de ser de lento y difícil crecimiento, inclusive hasta 8 semanas son necesarias para poder visualizar estructuras características del agente investigado. Es por ello que es importante desarrollar un medio de cultivo que aumente la sensibilidad de recuperación de hongos dimorfos, como el P. brasiliensis, a partir de muestras clínicas y provenientes de la micoteca; y que a su vez pueda ser utilizado para la obtención de la fase de levadura en forma eficaz. Se procesaron dos muestras clínicas y dos cepas provenientes de la Micoteca de la Sección de Micología Médica del Instituto de Medicina Tropical, los cuales fueron sembrados en: Sabouraud, agar cerebro corazón (brain heat), agar Kelley y agar Kelley Modificado a temperatura ambiente para obtener la fase micelial y a 37° C para incluir la transformación térmica y así recuperar la fase de levadura. En relación al crecimiento a temperatura ambiente, de las muestras clínicas se observó el crecimiento de una colonia característica de P. brasiliensis entre el séptimo día y la sexta semana en el siguiente orden: agar Kelley, agar Kelley modificado, agar brain heart y Sabouraud. En el caso de dos cepas provenientes de la micoteca a su desarrollo fue casi similar en Agar Kelley y Brain heart. Para la transformación a fase de levadura ésta se obtuvo antes de los 7 días con el agar Kelley Modificado y el agar Kelley.

Role of iron in the nitric oxide-mediated fungicidal mechanism of IFN-gamma-activated murine macrophages against Paracoccidioides brasiliensis conidia

Iron is an essential growth element of virtually all microorganisms and its restriction is one of the mechanisms used by macrophages to control microbial multiplication. Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis, an important systemic mycosis in Latin America, is inhibited in its conidia-to-yeast conversion in the absence of iron. We studied the participation of iron in the nitric oxide (NO)-mediated fungicidal mechanism against conidia. Peritoneal murine macrophages activated with 50U/mL of IFN-gamma or treated with 35 æM Deferoxamine (DEX) and infected with P. brasiliensis conidia, were co-cultured and incubated for 96 h in the presence of different concentrations of holotransferrin (HOLO) and FeS0(4). The supernatants were withdrawn in order to assess NO2 production by the Griess method. The monolayers were fixed, stained and observed microscopically. The percentage of the conidia-to-yeast transition was estimated by counting 200 intracellular propagules. IFN-gamma-activated or DEX-treated Mthetas presented marked inhibition of the conidia-to-yeast conversion (19 and 56 percent, respectively) in comparison with non-activated or untreated Mthetas (80 percent). IFN-gamma-activated macrophages produced high NO levels in comparison with the controls. Additionally, when the activated or treated-macrophages were supplemented with iron donors (HOLO or FeSO4), the inhibitory action was reversed, although NO production remained intact. These results suggest that the NO-mediated fungicidal mechanism exerted by IFN-gamma-activated macrophages against P. brasiliensis conidia, is dependent of an iron interaction.

O ferro é elemento essencial para o crescimento de microrganismos e sua limitação é um dos mecanismos usados por macrófagos para controlar a multiplicação microbiana. Paracoccidioides brasiliensis, o agente da paracoccidioidomicose, uma das micoses sistêmicas mais importantes na América Latina, é inibido em sua conversão de conídia-à-levedura na ausência do ferro. Estudamos a participação do ferro no mecanismo fungicida mediado pelo óxido nítrico (NO) na sua interação com as conídias do fungo. Macrófagos peritoneais murinos ativados com 50U/mL de IFN-gama ou tratados com 35 æM Deferoxamina (DEX) e infectados com conídias do P. brasiliensis foram co-cultivados e incubados por 96 h na presença de concentrações diferentes de holotransferrina (HOLO) e FeS0(4). Os sobrenadantes foram retirados a fim de avaliar a produção de NO2 pelo método de Griess. Os macrófagos eram fixados, corados e observados ao microscópio. A porcentagem da transição de conídia-à-levedura foi estimada contando 200 propágulos intracelulares. Os macrófagos ativados com citocina ou tratados com DEX apresentaram inibição marcada da conversão de conídia-à-levedura (19 e 56 por cento, respectivamente) em comparação com macrófagos controle (80 por cento). Os macrófagos ativados com IFN-gama produziram elevação nos níveis de NO em comparação com macrófagos não-tratados ou não-activados. Adicionalmente, quando as monocapas ativadas ou tratadas foram suplementadas com doadores do ferro (HOLO ou FeSO4), a ação inibitória foi revertida embora a produção de NO permanecesse intacto. Estes resultados sugerem que o mecanismo fungicida mediado pelo NO exercido por macrófagos ativados com IFN-gama contra conídias do P. brasiliensis é dependente de uma interação do ferro.

Inoculation of BALB/c mice with Lacazia loboi

In a previous study, the authors inoculated Swiss mice with Lacazia loboi (L. loboi) and succeeded in maintaining a granulomatous infiltrate and viable fungal cells up to one year and six months after inoculation. Considering the experimental work on paracoccidioidomycosis, 0.03 ml of a fungal suspension obtained from a biopsy of a Jorge Lobo's Disease patient were inoculated into both hind foot pads of 32 six week-old BALB/c mice of both sexes. The animals were sacrificed 1, 4, 7 and 10 months post inoculation. The suspension contained 1.3 x 10(6) fungi/ml and presented 38 percent viability. Seven months after inoculation, most of the animals presented profuse infiltrates consisting of isolated histiocytes, foreign body and Langhans' giant cells and a large number of fungi, most of them viable. Emergence of macroscopic lesions was observed during the 8th month. Based on fungal count, viability index before and after inoculation, presence of macroscopic lesions and histopathological findings similar to the findings in humans, the authors believe that BALB/c mice may be a good experimental model to study Jorge Lobo's Disease, mainly regarding therapeutic evaluation

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage

The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequencial in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM): acute form (group A, n=15) and chronic form (group C, n=15). The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups). The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1um in contrast with 32.9um exhibited by mother cells from group C (p<0.05). The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0um (SD + or - 4.0), a value significantly higher than the 14.1um (SD = + or - 3.3) exhibited by 1500 mother cells from group C isolates (0.05). Our results reinforce the polymorphism exhibited by P. brasiliensis in biological material and the need for further investigations to elucidate the role of morphological parameters of the fungus in the natural history of the disease

La infección pulmonar y sistémica causada por el Paracoccidioides brasiliensis. Avances recientes y perspectivas terapéuticas / Pulmonary and systemic infection caused by Paracoccidioides brasiliensis. Recent advances and therapeutic perspectives

La paracoccidioidomicosis es una infección fúngica subaguda o crónica adquirida por la inhalación del Paracoccidioides brasiliensis, caracterizada por la presencia de infiltados pulmonares "en mancha", y/o lesiones ulcesosa de la mucosa oronasal y la piel. La linfadenopatía es frecuente. En los casos diseminados, todas las vísceras pueden ser afectadas, pero las glándulas suprarrenales son especialmente susceptibles. El diagnóstico se confirma con el examen microscópico directo de los productos patológicos, la histopatología o el cultivo del agente infeccioso. Las técnicas de seroinmunología pueden ser de utilidad en el diagnóstico. Es endémica en las regiones tropicales y subtropicales de Sudamérica, Centroamérica y México. Los trabajadores con mayor riesgo son aquellos en contacto con el suelo, principalmente los campesinos, agricultores y obreros de la construcción; la incidencia más alta se ha registrado entre los adultos de 30 a 50 años de edad, siendo mucho más prevalente en los hombres que en las mujeres. El reservorio probablemente sea el suelo o la tierra cargada con las esporas del hongo. El medicamento de elección es el itraconazol. La anfotericina B seguida de una terapia prolongada con sulfas, resulta ser más barata pero menos efectiva. Sin embargo, los casos diseminados más graves, y la insuficiencia respiratoria residual representan un reto significativo a la terapéutica disponible.

Seguimiento post-terapia en pacientes con paracoccidioidomicosis tratados con itraconazol

De 80 pacientes con paracoccidioidomicosis (PCM) que, a partir de 1985, fueran diagnosticados en los laboratorios de la Corporación para Investigaciones Biológicas (CIB) y que recibieran tratamiento con itraconazol (ITZ), fue posible hacer un seguimiento post-terapia prolongado (promedio de 30 meses, rango 1-8 años) en 53 de ellos. Al momento del diagnóstico, 50 presentaban la forma crónica pulmonar del adulto y los 3 restantes, la forma juvenil. Cuatro de los enfermos estudiados habían recaído después de tratamiento con Ketoconazol. La mayoría de los pacientes (92.4 por ciento) recibieron 100 mgs diarios de ITZ, con una duración promedio de 6 meses de tratamiento en el 62 por ciento de los casos. Ninguno de los pacientes seguidos post-terapia presentó recaída durante el período de observación. Los sítomas más importantes a la terminación de la terapia fueron tos, expertoración y disnea, presentes al final de la terapia en 38.3 por ciento, 22.6 por ciento y 26.4 por ciento de los casos, respectivamente. Su frecuencia, sin embargo, disminuyó durante la observación post-terapia, persistiendo sólo la disnea en 35 por ciento de los casos. El seguimiento radiológico permitió observar la desaparición de los infiltrados retículo-nodulares presentes durante la terapia; sin embargo, la fibrosis fue permanente en 7 de los 11 pacientes que fueron seguidos por más de 4 años. En el 85 por ciento de los pacientes se notó un importante descenso en los títulos de anticuerpos contra el agente causal, P brasiliensis. Los anteriores hallazgos revelan la eficacia del ITZ en el tratamiento de la PCM; se comprueba que este triazol es superior a las drogas para administración oral o intravenosa anteriormente utilizadas ya que no se acompaña de recaídas.

Utilização de aminoácidos no estudo do crescimento do Paracoccidioides brasiliensis: influencia sobre o dimorfismo / Utilization of aminoacids in the study of the growth of Paracoccidioides brasiliensis. Influence on dimorphism

Utilizamos 15 amostras de Pacoccidioides brasiliensis nas formas miceliana (M) e leveduriforme (L), cultivadas em meio minimo (MM) e adaptadas ao mesmo meio suplementado com a solucao de aminoacidos (MMS). Para a realizacao do estudo auxologico das amostras, foram preparadas solucoes complementares das quais foram retirados um aminoacido de cada vez. Nove amostras foram prototroficas nas formas M e/ou L e as demais auxotroficas para os diferentes aminoacidos e bases nitrogenadas. A heterogeneidade dos resultados apresentados nao permitiu a caracterizacao auxologica das 15 amostras de P. brasiliensis estudadas. Nenhum dos compostos nitrogenados demonstrou ser essencial para o crescimento ou para a manuntencao da morfogenese do fungo. Alteracoes morfologicas (macro e microscopicas) tambem foram observadas, mas somente entre as amostras prototroficas, sugerindo a ativacao de um mecanismo de adaptacao desenvolvido pelo fungo mediante a ausencia de substratos nitrogenados no meio de cultura (MM).

Papel del hierro en el crecimiento del Paracoccidioides brasiliensis / Iron role in Paracoccidioides brasillensis growth

Se evaluo el crecimiento del Paracoccidioides Brasilensis en un medio de cultivo con diferentes concentraciones de hierro y frente a la edicion de agentes quelantes tales como transferrina serica humana, desferoxamina, y 1,10-fenantrolina y se elaboraron curvas de crecimiento. Como control se hizo la mismo con una cepa de Candida Albicans. No se obtuvo inhibicion del crecimiento del Paracoccidioides Brasiliensis en un medio de cultivo con baja concentracion de hierro ni aun frente a la adicion de quelantes. Contrariamente, al crecimiento de Candida Albicans si inhibio en los medios de cultivo a los cuales se adicionaron quelantes. Estos hallazgos continuan demostrando la facilidad del Paracoccidioides Brasiliensis por subsistir frente a condiciones aparentemente adversas

Contribuiçäo ao estudo da Paracoccidioidomicose na República do Equador / Contribution to study of the Paracoccidioidomycosis in Ecuador Republic

A partir dos dados de 133 pacientes com paracoccidioidomicose, obtidos do arquivo do Departamento de Micologia, do INHMT - LIP de Guayaquil, Equador, apresentamos consideraçöes sobre o diagnóstico micológico, epidemiologia clínica, e radiologia da doença. Demonstramos que a enfermidadde já é um problema de saúde pública no país, apesar de näo se conhecer sua real magnitude, em número de pacientes e extensäo das áreas endêmicas. Ressaltamos a importância do diagnóstico precoce nas regiöes rurais e damos sugestöes, visando ao adestramento do médico rural e do pessoal paramédico. Destacamos a facilidade do diagnóstico direto, pelo exame a fresco de fragmentos de simplicidade de execuçäo do teste de IDD. Assinalamos a bacia do Rio Guayas como a regiäo endêmica mais importante e discutimos o papel de outras regöes como zonas endêmicas atuais ou futuras. Apresentamos casos considerados ilustrativos de diversos quadros clínicos e radiológicos. Damos, finalmente, sugestöes tendentes a melhorar o conhecimento da doença, limitar as áreas endêmicas e favorecer o diagnóstico e tratamento da paracoccidioidomicose no Equador