Actinomycetes are a kind of terrestrial prokaryotes, which mainly grow in hyphae and reproduce through spores. It is named because it grows radially on solid media. Most of them have developed branched hyphae.

The hyphae of actinomycetes are divided into aerial hyphae, vegetative hyphae and spore hyphae.

1, the main function of matrix mycelium is to absorb nutrients and excrete metabolites.

2. Airborne hyphae can produce pigments, mostly fat-soluble pigments.

3. The main function of sporophyte is reproduction. When aerial hyphae develop to a certain stage, spores can be differentiated from them.

Spore filaments of actinomycetes are various in shape, including straight, wavy, hooked, spiral, primary whorl and secondary whorl, which is one of the important signs of actinomycetes colonization. Spore filaments differentiate into conidia at a certain stage of development. Under the optical microscope, spores are round, oval, rod-shaped, cylindrical, melon-seed-shaped, spindle-shaped and half-moon-shaped, and the colors of spores are very rich.

Etiology of actinomycosis

The common pathogens causing human actinomycosis are mainly Israeli actinomycetes, bovine actinomycetes and Leigh's actinomycetes, as well as cobwebs of propionic acid and Bifidobacterium of Bifidobacterium. Actinomycetes belong to prokaryotic microorganisms, which have developed hyphae and spores, but the hyphae are mostly single-celled structures. There are no fixed nuclei in hyphae and spores, but only scattered nucleosomes in cytoplasm; There are no organelles such as mitochondria and chloroplasts in the cytoplasm, and the chemical composition of the cell wall is similar to that of bacteria (mainly peptidoglycan compounds form reticular complexes), which is significantly different from that of fungi. The main component of nucleosome is DNA, but there is no histone, which is unique to eukaryotic chromosomes. Sensitive to antibiotics such as lysozyme and penicillin, but resistant to fungal drugs, because actinomycetes can produce hyphae and spores, much like fungi, and because the clinical manifestations of diseases caused by them are difficult to distinguish from fungal diseases.

Therefore, according to traditional habits and clinical needs, actinomycosis should be classified as mycosis. These pathogenic bacteria are anaerobic bacteria or microaerobic bacteria, which are often a normal flora in the human body, especially in the oral cavity. If there is trauma, infection can occur after operation, and bacterial infection often occurs after infection. The damage gradually spread from the center through the sinuses to the surrounding area, invading the skin, subcutaneous tissue, muscles, fascia, bones and internal organs.