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A preliminary study on the ultrastructure of Actinomadura pelletieri and its host tissue reaction
A H Fahal1, E A el Toum, A M el Hassan
1Department of Surgery, Faculty of Medicine, University of Khartoum, Sudan.
Abstract:
This is the first report on the fine structure of Actinomadura pelletieri. The in vitro ultrastructure of the organism and that of the grain in vivo were similar. The grain consisted of packed filaments with a faintly electron-dense matrix in between. The individual filament was septate, the cytoplasm was either vacuolated or contained intracellular organelles and the cytoplasmic membrane was adherent to the filamentous wall, which has three electron-dense and two electron-lucent layers. The absence of cement substance around the grain may partially explain the aggressive and destructive behaviour of this organism and may probably also explain its good response to medical treatment. The inflammatory host reaction was similar to that seen with all mycetoma organisms except that there was a massive neutrophil reaction. This was confirmed by electron microscopy.
Insights
This study reveals the fine structure of Actinomadura pelletieri, showing its filaments and unique cell wall. The absence of cement substance may explain its aggressive behavior and treatment response in mycetoma.
Area of Science:
- Microbiology
- Pathology
Background:
- Actinomadura pelletieri causes mycetoma, a destructive infection.
- Its fine structure and interaction with the host are not well understood.
Purpose of the Study:
- To describe the fine structure of Actinomadura pelletieri in vitro and in vivo.
- To correlate ultrastructural features with the organism's pathogenicity and treatment response.
Main Methods:
- Transmission electron microscopy was used to examine the ultrastructure of Actinomadura pelletieri.
- In vitro and in vivo samples (grains) were analyzed.
Main Results:
- The organism's grain consists of packed filaments with an electron-dense matrix.
- Filaments are septate with vacuolated or organelle-containing cytoplasm and a complex cell wall.
- Absence of cement substance and massive neutrophil reaction were observed.
Conclusions:
- The fine structure of Actinomadura pelletieri is similar in vitro and in vivo.
- Lack of cement substance may contribute to aggressive behavior and treatment efficacy.
- A massive neutrophil response is characteristic of this infection.