Nocardiaceae
Family of bacteria
From Wikipedia, the free encyclopedia
The Nocardiaceae are a family of aerobic, non-fastidious, high G+C, Gram-positive actinomycetes that are commonly found in soil and water.[3] Members of this family have been isolated from Antarctic soils.[4] Nocardiaceae present coccobacilli, filamentous or, rarely, fragmented and palisading forms,[5] and filamentous species grow in a branching morphological pattern similar to fungal hyphae.[6]
| Nocardiaceae | |
|---|---|
| |
| Nocardia asteroides colonies | |
Scientific classification  | |
| Domain: | Bacteria |
| Kingdom: | Bacillati |
| Phylum: | Actinomycetota |
| Class: | Actinomycetes |
| Order: | Mycobacteriales |
| Family: | Nocardiaceae Castellani and Chalmers 1919 (Approved Lists 1980)[1] |
| Type genus | |
| Nocardia Trevisan 1889 (Approved Lists 1980) | |
| Genera[2] | |
| |
| Synonyms | |
| |
Genomics
The Nocardiaceae form a monophyletic clade within the Corynebacteriales in both 16S rRNA and protein-based phylogenetic trees.[7][8] A number of conserved signature indels and conserved signature proteins have been identified which are uniquely found in the genera Nocardia and Rhodococcus, supporting a close relationship between the two genera.[8] Recent proposals have been made, based on 16S rRNA signature nucleotides and chemotaxonomic markers, to add the genera Gordonia, Skermania, Williamsia, Millisia, and Smaragdicoccus to the family Nocardiaceae.[7][9] However, no conserved signature indels or proteins have been found that are commonly shared by Nocardia, Rhodococcus, and Gordonia, the fully sequenced members of the proposed Nocardiaceae revision.[8]
Pathogenic capacity
Some species colonize animals, and members of the Nocardia and Rhodococcus genera can cause infection in humans and livestock.[10] Nocardiosis represent also a serious health problem for fish (marine or not).[11] Many members of this family integrate mycolic acids into their cell wall, and as a result, Nocardia spp. may be mistaken for mycobacteria when viewed under a microscope following an acid-fast stain.[12]
Environmental effects
Wastewater foaming
Nocardia species are often responsible for the accumulation of foam that occurs in activated sludge during sewage treatment.[6][13][14][15] Biological foaming can be problematic for the water treatment process, and foam accumulation is reduced by adding surfactants to the wastewater.[16][17]
Bioremediation of hydrocarbons
Soil Nocardiaceae can degrade hydrocarbons (e.g. petroleum distillates) and have been proposed as bioremediation agents for environmental spills.[18]
Nomenclature changes
In the 1980s, all Nocardiaceae species assigned to the genus Micropolyspora were transferred to the genera Nocardia or Nonomuraea in family Streptosporangiaceae, or Saccharopolyspora in family Pseudonocardiaceae.[19] This effectively ended the official status of this genus, but the name persists in older research articles.