CHLORAMPHENICOL

antibiotic substance of molecular formula C11H12Cl2N2O5, originally found as a product of the metabolism of the soil bacterium Streptomyces venezuelae (order Actinomycetales) and now synthesized chemically. It is effective against many disease-causing bacteria, rickettsias, and Mycoplasma but is the preferred treatment only for typhoid fever. Chloramphenicol achieves its antibacterial effect by interfering with protein synthesis in these microorganisms. The drug can cause serious bone marrow disturbances and can prove toxic to newborn infants.