The Effect of Chloramphenicol on Bacteria

Chloramphenicol is an antibiotic that gained popularity in the late 1940s. However, due to a number of dangerous side effects, chloramphenicol is no longer given to humans unless other the bacterial infection is resistant to other antibiotics. Chloramphenicol destroys a wide spectrum of bacteria, including many gram-positive and gram-negative cocci and bacilli. It is now commonly prescribed by veterinarians.

Chemistry

• The chemical formula for chloramphenicol is C11H12Cl2N2O5. Because chloramphenicol has a neutral pH, it is able to move freely through cell membranes and into vital organs, which makes it chemically flexible and able to attack a wide spectrum of bacteria. Chloramphenicol's chemistry also allows the antibiotic to easily break down within the body and be eliminated through urine.

History

• Scientists extracted chloramphenicol from the bacteria Streptomyces venezuelae in 1947, and found it to be a powerful antibiotic against strong, antibiotic-resistant strains of bacteria. Chloramphenicol was extremely effective against typhus epidemics, and so was mass-produced starting in 1948. However, by 1950, the scientific community was aware of the extreme side effects of chloramphenicol, and doctors stopped using the antibiotic for humans.

Effect on Bacteria

• Chloramphenicol destroys bacteria by attacking the bacteria's ability to manufacture proteins. When a bacteria attempts to make protein in its ribosomes, chloramphenicol prevents proper assembly, either killing the bacteria or preventing it from dividing and reproducing. However, the ribosomes of mammals and birds appear to be unaffected by chloramphenicol.

Side Effects

• Many patients who took chloramphenicol suffered from bone marrow depression, reducing bone marrow growth and function. Aplastic anemia is the most dangerous side effect, preventing the bone marrow from producing new cells to replenish blood cells. Another danger is gray baby syndrome, in which a fetus or newborn is unable to process chloramphenicol ingested by the mother, leading to bone marrow problems in the baby. Chloramphenicol is also considered a carcinogen.

Uses

• Chloramphenicol is only used by humans if the bacteria involved are resistant to other, less-dangerous antibiotics. However, because dogs, cats and birds do not suffer the same bone-related side effects, Chloramphenicol serves as a common oral antibiotic for veterinarians. Chloramphenicol is a useful antibiotic for pets when fighting pneumonia or intracellular parasites like chlamydia or rickettsia, or when dealing with bacteria in the central nervous system, eyes or prostate.