Rhodococcus cerastii

Rhodococcus cerastii is a Gram-positive, rod-shaped bacteria of the family Nocardiaceae. Colonies appear circular in form, convex in elevation, and pale yellow in color when grown on tryptic soy agar (TSA).^[1]

Rhodococcus cerastii
Scientific classification
Domain:	Bacteria
Kingdom:	Bacillati
Phylum:	Actinomycetota
Class:	Actinomycetes
Order:	Mycobacteriales
Family:	Nocardiaceae
Genus:	Rhodococcus
Species:	R. cerastii
Binomial name
Rhodococcus cerastii Kämpfer et al., 2013

It is a typical component of soil ecosystems where it has been successfully isolated from both soil and the surface of Cerastium holosteoides (the common mouse-ear chickweed) leaves.^[1][2] When incubated in tryptic soy broth, these aerobic rods exhibit optimal growth conditions of 30 °C (86 °F), a pH between 7–8, and 2–3% sodium chloride (${\displaystyle {\ce {NaCl}}}$). However, there has been successful growth present within the following ranges: 15–50 °C (59–122 °F), pH 6.5-10.5, and 1-6% ${\displaystyle {\ce {NaCl}}}$^[1]

Notably, most research on R. cerastii focuses on the bacterial responses and adaptations to ibuprofen-related stressors. Specifically, a study conducted by Tyumina et al. found that R. cerastii moderately degraded the NSAID with patterns of increased metabolic activity and initially decreased catalase activity.^[2] Subsequent morphometric analysis found changes in size, shape, and surface roughness in directly exposed bacteria. Ibuprofen-treated R. cerastii samples exhibited lipid inclusions, polyphosphate granules, and intracellular membrane-like structures. Similarly, another study by Ivshina et al.proved that R. cerastii possesses a notably high ibuprofen tolerance with a promising potential for the biodegradation of ibuprofen under cometabolic conditions. Exposed samples commonly showed the formation of loose, needle-like, pale yellow aggregates.^[3]