Nocardiaceae

Nocardiaceae
Nocardia asteroides colonies
Scientific classification
Kingdom:	Bacteria
Division:	Actinobacteria
Class:	Actinobacteria
Subclass:	Actinobacteridae
Order:	Actinomycetales
Suborder:	Corynebacterineae
Family:	Nocardiaceae Garrity et al. 2001
Genera
Nocardia Rhodococcus Smaragdicoccus Micropolyspora (now defunct)

The Nocardiaceae are a family of aerobic, non-fastidious, high G+C, Gram-positive actinomycetes that are commonly found in soil and water.^[1] Members of this family have been isolated from Antarctic soils.^[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 activated 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 1980s, all Nocardiaceae species assigned to the Micropolyspora genus 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.

References

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. ^ ^{a b} 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: aids-images.ch. 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. ^ Micropolyspora entry in LPSN [Euzéby, J.P. (1997). "List of Bacterial Names with Standing in Nomenclature: a folder available on the Internet". Int J Syst Bacteriol 47 (2): 590-2. doi:10.1099/00207713-47-2-590. ISSN 0020-7713. PMID 9103655. http://ijs.sgmjournals.org/cgi/reprint/47/2/590. ]