The biology and genetics of the genus Rhodococcus

The genus Rhodococcus is a unique taxon consisting of microorganisms that exhibit broad metabolic diversity, particularly to hydrophobic compounds such as hydrocarbons, chlorinated phenolics, steroids, lignin, coal, and petroleum. Advances in chemical, numerical, and molecular systematic methods have contributed greatly to the circumspection of the rhodococci, including the development of diagnostic fluoregenic probes for improved biochemical profiling and identification. Bioprocessing systems employing various Rhodococcus strains are operational for industrial and environmental applications. Such applications include production of acrylic acid and acrylamide, steroid conversions, and bioremediation of chlorinated hydrocarbons and phenolics. Progress on the genetic systems of the rhodococci is rather limited, although a number of plasmids, cloning vectors, and DNA transfer systems have been reported recently, such that progress should be rapid. Certain members of the genus Rhodococcus are known pathogens for humans, animals, and plants. Recent trends indicate that rhodococci of animal origin are opportunistic human pathogens, indicating the need for a greatly improved recognition and understanding of the virulence factors associated with the genus Rhodococcus.