Actinomycetaceae

Actinomyces israelii

Actinomyzetaceae is a family of bacterial order Actinomycetales, which is expected 5 genera. The genus Actinomyces contains the most species. Characteristic of Actinomycetaceae are elongated, often branched cells, with the exception of the genus Mobiluncus without active movement, predominantly anaerobic growth and positive behavior in the Gram stain.

The family Actinomycetaceae is often referred to as the " Actinomycetes " or " actinomycete ". However, these names are not unique, because thus the order Actinomycetales and the genus Actinomyces are known.

Shape, cell structure

Actinomycetes usually form straight or curved rod-shaped cells with a diameter of 0.2 to 3.0 microns. The length is very different, there are short coccoid cells before and even long filamentous up to a length of 50 microns or even more. Some species form small, branched mycelia. The langfädigen shapes and mycelia proliferate occasionally decay into short cells ( segmentation ). Actinomycetes are Gram- positive. Active movement occurs only in the species Mobiluncus, by in each case a flagellum or more (up to 8), which are located at a cell end. In this genus also forms occur, although they possess a typical cell wall of Gram-positive bacteria, which is so thin that they are Gram- variable in the Gram stain or Gram negative behavior.

Metabolism

Actinomycetes are predominantly anaerobic, facultatively aerobic, some are only a few possess catalase. In some species (CO2 ) and bicarbonate ( HCO3- ) concentration is in the medium allows growth under aerobic conditions by a high carbon dioxide. Most actinomycetes need to grow a complex nutrient supply. Often they have a fermentative energy metabolism, are reacted at the carbohydrates into organic acids, In the genus Varibaculum reduction of nitrate ( NO3- ) to nitrite (NO2 - ) occurs in the genus Mobiluncus will fumarate reduced to malate and some of these species can nitrate reduce.

Occurrence of life

Most actinomycetes are found in warm-blooded vertebrates, either as pathogens or as commensals. Therefore, the optimum temperature of growth is relatively high: 30 - 37 ° C. The pathogens cause various diseases, including Aktinomykosen.

Genera and species ( selection)

The Actinomycetaceae family includes the following genera, plus a variety of ways:

  • Actinobaculum Lawson et al. 1997
  • Actinomyces Harz 1877 Actinomyces bovis Harz 1877 ( type species )
  • Actinomyces funkei Lawson et al. 2001
  • Actinomyces gerencseriae Johnson et al. 1990
  • Actinomyces graevenitzii Pascual Ramos et al. 1997
  • Actinomyces israelii ( Kruse 1896) Lachner - Sandoval 1898
  • Actinomyces naeslundii Thompson & Lovestedt 1951
  • Actinomyces odontolyticus Batty 1958
  • Arcanobacterium haemolyticum (ex MacLean et al. 1946) Collins et al. 1983
  • Arcanobacterium pyogenes ( Glage 1903) Pascual Ramos et al. 1997
Actinobacteria Fermentation
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