Experimental murine chromoblastomycosis obtained from Fonsecaea pedrosoi isolate cultured for a long periodt

The present study aimed to describe F. pedrosoi propagules capable of causing chronic murine disease. Several changes in F. pedrosoi hyphae were identified in fungal cells cultured for a long period. Optical microscopy found many rounded cells with double-rigid melanin-rich walls. Terminal and intercalary chlamydoconidia were also frequently observed. Analyses of images from transmission electron microscopy (TEM) revealed several cells with walls composed of at least three layers and an outer layer enriched with melanin. Two groups of twenty BALB/c mice were subcutaneously infected in their footpads with F. pedrosoi cells at an inoculum concentration of approximately 1 x 10(4) cells/mL. In one group, long-term cultured F. pedrosoi cells were inoculated in one footpad, whereas in the other group, both footpads were infected. Active lesions were observed up to seven months post-infection, particularly in mice inoculated at two sites. After this period, animals were killed. Histological sections revealed characteristics bearing a strong resemblance to the human form of the disease such as tissue hyperplasia, granulomas with microabscesses and sclerotic cells. Based on this study, we identified fungal cells from old cultures capable of provoking chronic chromoblastomycosis under experimental conditions, especially when more than one site is infected.

Biliary and pancreatic stent blockage by bacterial biofilm: presentation of two cases

Biliary and pancreatic stents are effective tools in the management of obstructive jaundice (both malignant and benign), pancreatic pseudocyst drainage, and as treatment for biliary and pancreatic fistulae. Unfortunately, stents may become blocked and require replacement in a number of patients. In the present study a blocked stent from a patient with transpapillary drainage of pancreatic pseudocyst and another from a patient with obstructive jaundice resulting from cancer of the head of the pancreas associated with Mirizzi syndrome were characterized by electron microscopy. Stent blockage was diagnosed by a pressure test and stent cultures were performed. Electron microscopy of the blocked stents revealed the sludge to consist of microcolonies of bacteria mixed with amorphous material, and cultures of both stents were positive for Klebsiella sp and E. coli.

Sorotipos de Escherichia coli enteropatogênica clássica (EPEC) causadores de alteraçöes da ultra-estrutura do intestino delgado e invasäo de células Hela / Serotypes of classical enteropathogic that cause changes in the small bowel ultrastructure and invasion of Hela cells

Escherichia coli enteropatogênica clássica (EPEC) é a principal causa de diarréia em lactentes menores de um ano de idade nos países subdesenvolvidos. In vitro, cepas de EPEC sao capazes de aderir a células HeLa ou Hep-2, obedecendo um padrao característico denominado adesao localizada. Estudos in vivo demonstram que as cepas de EPEC provocam profundas alteraçoes nas micro-vilosidades do enterócito, causando lesoes em pedestal. Objetivos. Neste trabalho, os autores relatam as alteraçoes da ultra-estrutura do intestino delgado causada pelos sorotipos 0111ab:H2, 0119:H6 e 018ab:H14, em lactentes portadores de diarréia aguda, e a capacidade destas bactérias de penetrar e se multiplicar no interior de células HeLa. Pacientes e Métodos. Estes sorotipos de EPEC foram isolados das fezes de três pacientes portadores de diarréia aguda que apresentaram intolerância alimentar e agravo nutricional. Alteraçoes ultra-estruturais do intestino delagado foram observadas nos espécimes estudados com formaçao de pedestal e penetraçao das bactérias no interior do citoplasma dos enterócitos. Estas bactérias também penetraram e se multiplicaram no interior das células HeLa. Conclusao. As alteraçoes ultra-estruturaisdescritas em pacientes com diarréria aguda devem ser levadas em conta quanto ao seu potencial efeito de provocar prolongamento da diarréia, seja por um fenômeno secretor ou por má absorçao dos nutrientes.