chloramphenicol CAS:56-75-7 antibiotic_resistance ARO:3000385 ChEBI:17698 ChEMBL:CHEMBL130 PubChem:5959 CHL Chloramphenicol is a bacteriostatic antimicrobial originally derived from the bacterium Streptomyces venezuelae. It was the first antibiotic to be manufactured synthetically on a large scale. It functions by inhibiting peptidyl transferase activity of the bacterial ribosome, binding to A2451 and A2452 residues in the 23S rRNA of the 50S ribosomal subunit and preventing peptide bond formation. phenicol antibiotic