Chl orampheni col , an antibiotic isolated from Streptomyces venezuelae ,x was the first antimicrobial used in gynecology as a broad-spectrum agent. Parke Davis Laboratories unraveled its chemical structure and marketed the synthetic product, Chloromycetin, after developing a method of synthesizing D(-)-threo-pnitrophenyl-2-dichloracetamido-l ,3-propanediol, the chemical formula of the antibiotic.Chloramphenicol is a bacteriostatic agent that inhibits protein synthesis by binding to a protein receptor of the 50 S subunit of the ribosome of susceptible bacteria. Its interaction with the ribosomal subunit interferes with the transpeptidation reaction that takes place at the amino acid acceptor site of bacterial ribosomes. Bacteria exposed to chloramphenicol in the laboratory are able to resume protein synthesis when the antibiotic is removed." Chloramphenicol is active against many gram-negative aerobic and anaerobic bacteria as well as gram-positive cocci and bacilli of importance in gynecologic infections. Enterobacteriaceae, such as Escherichia coli, Klebsiella, and Proteus, are sensitive. However, resistance may develop by selection of organisms with an R plasmid-mediated transferable factor when chloramphenicol is used extensively. In addition, if choramphenicol is used in combination with aminoglycoside antibiotics, such as gentamicin, it may suppress the rapid bactericidal effect of the aminoglycosides against some of the gram-negative aerobic bacteria.3 On the other hand, some strains of Enterobacteriaceae resistant to beta-lactam antibiotics may become sensitive when chloramphenicol is used in combination with them due to the ability of chloramphenicol to inhibit beta-lactamase production.4Gram-negative anaerobic bacteria are of special importance in obstetric and gynecologic infections. Most species ofBacteroides are susceptible to chloramphenicol. However, the activity of chloramphenicol against clinically important anaerobes is not superior to that of other drugs, such as metronidazole, clindamycin, or most second-generation cephalosporins. Although rare, Bacteroides resistance to chloramphenicol may occur. Two types of resistance have been reported. The most common type is by R plasmids that code for chloramphenicol resistance.5 Some strains of Bacteroides fragilis also may produce chloramphenicol acetyltransferaseconstitutively.6 Aerobic and anaerobic gram-positive cocci of importance in obstetric and gynecologic infections, including beta-lactamase-producing Staphylococcus aureus, the beta-hemolytic streptococci, peptococci, and peptostreptococci, are sensitive to chloramphenicol. Neisseria gonorrhoeae, Treponema pallidum, and the mycoplasmas are among the pathogenic organisms acquired during sexual activity that are known to be sensitive to chloramphenicol. Genital strains of Chlamydia trachomatis are not sensitive to chloramphenicol.Chloramphenicol is excreted predominantly as the inactive conjugated glucuronide form in the urine. Since conversion to the inactive form occurs in the liver, the activ...
