Chloramphenicol
Chloramphenicol is a broad-spectrum antibiotic that is small enough to effect
areas of the body that are too small for other antibiotics to enter. Chloramphenicol
is an antibiotic of last resort because it inhibits formation of blood cells, causing
aplastic anemia.
Macrolides
Macrolides are a group of antibiotics that have a similar effect as that of peni-
cillin G. They affect the organism by inhibiting its ability to synthesize protein
and are a secondary drug when penicillin G is unavailable or the organism has
become resistant to penicillin G. Macrolide antibiotics can be administered
orally, making them the choice for treating children who have streptococcal and
staphylococcal infections. The most commonly used macrolide is Erythromycin,
which is used to treat legionellosis, mycoplasmal pneumonia, and streptococcal
and staphylococcal infections.
PLASMA MEMBRANE INHIBITORS
Plasma membrane inhibitors are antibiotics that interfere with the functionality
of the plasma membrane of a pathogen. The commonly used plasma membrane
inhibitor antibiotic is Polymyxin B, which combats gram-negative bacteria such
as Pseudomonas.Today, when combined with neomycin, it is used in nonpre-
scription topical antibiotics for superficial infections.
NUCLEIC ACID INHIBITORS
Nucleic acid inhibitors interfere with the formation of nucleic acids. The com-
monly used nucleic acid inhibitor antibiotics follow.
Rifamycins
Rifamycins comprise a group of antibiotics that inhibit mRNA synthesis. They
are used to treat tuberculosis and leprosy. Rifamycins can reach the cere-
brospinal fluid and enter tissues and abscesses. The disadvantage of rifamycins
is that they cause urine, feces, saliva, sweat and tears to appear an orange-red
CHAPTER 16 Antimicrobial Drugs^241