The importance of serological assays in diagnosing acute pulmonary histoplasmosis

Histoplasmosis is a systemic mycosis caused by inhalation of Histoplasma capsulatum microconidia. The disease does not normally affect immunocompetent individuals after a single, transient inhalation exposure. However, longer exposure may cause chronic or disseminated acute pulmonary infection. Herein, we report the case of a 24-year-old immunocompetent patient, who presented fever, cough and dyspnea for one month. The chest radiography revealed interstitial infiltrate and diffuse micronodules. The patient reported having had close and prolonged contact with bats. Diagnosis was confirmed by positive double immunodifusion and immunoblotting assays. She was treated with ketoconazole (400 mg) and there was complete resolution of the disease.

Use of immunoblotting assay improves the sensitivity of paracoccidioidomycosis diagnosis

The purpose of this work was to evaluate two serological assays: double immunodiffusion (DI) and immunoblotting (IB) in immunodiagnosis of paracoccidioidomycosis (PCM). We evaluated by IB assay 23 sera samples from patients with clinical confirmation of PCM, all of them with negative DI results against culture filtrate from Paracoccidioides brasiliensis isolate 113. For IB, as well as for comparative DI assay, we employed soluble components of the cell wall outer surface (SCCWOS) from P. brasiliensis isolate 113 cultivated at 36°C in Fava-Neto's agar medium for 5 and 10 days. Among the 20 sera samples analyzed by DI, 13 (65 percent) were negative and 7 (35 percent) were positive against SCCWOS obtained on the 5th and 10th days. By IB assay, 95.4 percent and 100 percent of sera reacted against gp43 and gp70 present in SCCWOS from the 5th day and 95.6 percent recognized these fractions when evaluated against SCCWOS from the 10th day. Our results demonstrated that the use of an immunoenzymatic assay significantly improves the sensitivity of PCM immunodiagnosis and also suggests that at least two serological tests for antibody detection should be adopted in cases of questionable diagnosis.

Lung tissue mechanics in the early stages of induced paracoccidioidomycosis in rats

Pulmonary dysfunction represents the most important cause of death in patients with paracoccidioidomycosis (PBM). In order to investigate the functional changes of the lungs in the early stages of PBM, a model of benign disease was developed by intratracheal challenge of 12-week old isogenic Wistar rats with 1 x 10(6) yeast forms of Paracoccidioides brasiliensis. Animals were studied 30 and 60 days after infection, when fully developed granulomas were demonstrable in the lungs. Measurements of airway reistance, lung elastance and tissue hysteresis were made during sinusoidal deformations (100 breaths/min, tidal volume = 2 ml) with direct measurement of alveolar pressure using the alveolar capsule technique. Infection caused a significant increase in hysteresis (infected: 1.69, N = 13; control: 1.13, N=12,P = 0.024, ANOVA), with no alterations in airway resitance or lung elastance. Histopathological analysis revealed the presence of fully developed granulomas located in the axial compartment of the lung interstitial space. These results suggest that alterations of tissue mechanics represent an early event in experimental PBM.

In vitro action of some disinfectants on Paracoccidioides brasiliensis yeast forms

Descreveu-se a acao fungicida do hipoclorito de sodio (0,3; 1; 2,5; 5 e 10 por cento); do formaldeido (em solucao aquosa a 2,5 e 10 por cento); e alcool etilico a 70,0 por cento sobre formas leveduriformes de 2 cepas de Paraccoccidioides brasiliensis: Pb 18 e cepa Goiana, recentemente isolada. A incubacao do fungo e desinfetantes foi realizada a temperatura ambiente por periodos de 1, 2, 24, 48 e 72 horas. A viabilidade foi avaliada pelo tratamento com diacetato de fluoresceina-brometo de etideo; pela cultura em meios solidos e liquidos a 36 graus Celsius e 26 graus Celsius; transformacao de levedura em micelio a temperatura ambiente; e estudo radiometrico da atividade metabolica. Todas as concentracoes de todos os desinfetantes estudados foram capazes de inativar ambas as cepas, exceto na incubacao com formaldeido a 2 por cento por 1 hora, em que o tratamento por diacetato de fluoresceina-brometo de etideo revelou 40 por cento e 27 por cento de celulas viaveis, respectivamente, para a cepa Pb 18 e Goiana. A transformacao de levedura em micelio foi considerada um metodo rapido, com resultados semelhantes ao cultivo em meios solidos e liquidos.