Research has shed light on the structural basis of resistance to certain antibiotics, including phenicol and oxazolidinone. The resistance is mediated by various factors, including genes such as poxtA, and has been observed in different bacteria, including enterococcal isolates from a swine farm and enterococci found in human patients. The mechanisms of resistance appear to involve multiple pathways and factors, including ABCF-mediated resistance and the presence of specific genes like optrA and cfr.