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Scientific classification
Kingdom: Bacteria
Division: Actinobacteria
Class: Actinobacteria
Subclass: Actinobacteridae
Order: Actinomycetales
Suborder: Corynebacterineae
Family: Nocardiaceae
Garrity et al. 2001

Micropolyspora (now defunct)

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The Nocardiaceae are a family of aerobic, non-fastidious, high G+C, Gram-positive actinomycetes that are commonly found in soil and water.[1] Some bacteria from this family are even indigenous to the Antarctic.[2] Nocardiaceae present coccobacilli, filamentous or, rarely, fragmented and palisading forms,[3] and filamentous species grow in a branching morphological pattern similar to fungal hyphae.[4]

Pathogenic capacity

Some species colonize animals, and members of the Nocardia and Rhodococcus genera can cause infection in humans and livestock.[5] 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.[6]

Environmental effects

Wastewater foaming

Nocardia species are often responsible for the accumulation of foam that occurs in activate sludge during wastewater treatment.[4][7][8][9] Biological foaming can be problematic for the water treatment process, and foam accumulation is reduced by adding surfactants to the wastewater.[10][11]

Bioremediation of hydrocarbons

Soil Nocardiaceae can degrade hydrocarbons (e.g. petroleum distillates) and have been proposed as bioremediation agents for environmental spills.[12]

Nomenclature changes

In the 1980's, all Micropolyspora spp. were transferred to the genera Nocardia, Nonomuraea in family Streptosporangiaceae, or Saccharopolyspora in family Pseudonocardiaceae.[13] This effectively ended the official status of this genus, but the name persists in older research articles.


  1. Stackebrandt, E., Rainey, F.A. and N.L. Ward-Rainey. 1997. Proposal for a new hierarchic classification system, Actinobacteria classis nov. Int. J. Syst. Bacteriol., 1997, 47:479-491.
  2. Aislabie, J. Ecosystems Processes in Antarctic Ice-Free Landscapes. "Hydrocarbon-degrading bacteria in oil-contaminated soils near Scott Base, Antarctica." Page 257.
  3. Kulich, S.M. and W.A. Pasculle. Final Diagnosis - Pneumonia, Hilar Lymphadenitis and Sepsis Secondary to Rhodococcus equi. The University of Pittsburgh School of Medicine. Retrieved October 20, 2007.
  4. 4.0 4.1 Bitton, G. Wastewater Microbiology. "Foam Microbiology." page 229.
  5. Castellani, A. and A.J. Chalmers. 1919. Manual of Tropical Medicine, 3rd ed., Williams Wood and Co., New York, p. 1040.
  6. Nocardia: a serious matter for cows. Presentation images from: Retrieved October 20, 2007.
  7. Blackall, L.L., Tandoi, V., Jenkins, D. 1991. Continuous culture studies with Nocardia amarae from activated sludge and their implications for Nocardia foaming control. Res. J. Water Pollution Cont. Fed. 63:44-50.
  8. Pitt, P., and D. Jenkins. 1990. Causes and Control of Nocardia in Activated Sludge. Res. J. Water Pollution Cont. Fed. 62:143-150.
  9. Blackall, L.L. 1994. Microorganisms in activated sludge and biofilm processes. Water Sci. Technol. 29:35-44.
  10. Shao, Y.J., Starr, M., Kaporis, K., Kim, H.S., Jenkins, D. 1997. Polymer addition as a solution to Nocardia foaming problems. Water Enviro. Res., 69:25-27.
  11. Ho, C.F., Jenkins, D. 1991 Effect of surfactants on Nocardia foaming in activated sludge. Water Sci. Tech. 23:879-887.
  12. Aislabie, J., McLeod, M., and R. Fraser. Potential for biodegradation of hydrocarbons in soil from the Ross Dependency, Antarctica. Appl. Microbiol. Biotechnol. 49:210-214.
  13. Euzéby. J.P. List of Prokaryotic names with Standing in Nomenclature - Genus Micropolyspora. From: Retrieved October 20, 2007


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