The aerobic actinomycetes have been described as consisting of "heterogeneous and taxonomically divergent genera"58. As mentioned previously, many taxonomy changes have taken place with the advent of genetic testing.
Similar, less commonly isolated organisms within the aerobic actinomycetes include59:
| Other Similar Organisms | Notable Characteristics |
Amycolata, Amycolatopsis, Pseudonocardia
| Amycolata and Amycolatopsis were removed from the Nocardia genus because they are modified acid-fast negative. Rarely associated with human disease. An isolate found in the infected pharyngeal mucosa of an elderly patient. |
Dermatophilus (D. congolensis)
| Causing disease in cattle; in humans, skin lesions and chronic nodular disease |
Dietzia (D. maris, D. cinnamea, D. pappillomatosis, D. aurantiaca)
| Once considered a Rhodococcus. D. maris is most often identified; causes bacteremia; associated in an infection of a hip prosthesis |
Nocardiopsis (N. dassonvillei and N. synnemataformans)
| Members of Actinomadura dassovillei were moved recently to Nocardiopsis. Causes mycetoma and abscesses |
Segniliparus (S. rotundus and S. rugosus)
| Strongly acid-fast. Most closely related to Rhodococcus. S rotundus isolated from bronchial isolates, S. rugosus associated with cystic fibrosis patients. |
58. Mochon AB, Sussland D, Saubolle MA. Aerobic actinomycetes of clinical significance. Microbiol Spectr. 2016;4(4):10.1128/microbiolspec.DMIH2-0021-2015. doi:10.1128/microbiolspec.DMIH2-0021-2015
59. Conville PS, Brown-Elliott BA, Witebsky FG. Nocardia, Rhodococcus, Gordonia, Actinomadura, Streptomyces, and other aerobic actinomycetes. In: Carroll KC, Pfaller MA, Landry ML, McAdam AJ, Patel R, Richter SS, Warnock DW, eds. Manual of Clinical Microbiology, 12th ed. ASM Press; 2019:525-557.
60. CDC/Berd. Image #3078. This photograph depicted three slant cultures, which demonstrated the variations in colonial appearance among aerobic Actinomycetales bacteria. PHIL public domain. Created 1972. Accessed October 27, 2022. https://phil.cdc.gov/Details.aspx?pid=3078
