Other Agents That Inhibit Bacterial Cell Wall Synthesis

Other Agents That Inhibit Bacterial Cell Wall Synthesis 

Colistin. Colistin (also known as colistimethate or polymyxin E) is similar to polymyxin B in terms of 

Ertapenem. Ertapenem (Invanz) is another car-bapenam antibacterial agent that is similar to mero-penem (see below).11 Ertapenem is effective against gram-positive and gram-negative aerobic and anaerobic bacteria, and is often used to treat intra-abdominal and pelvic infections, as well as infections in the skin, urinary tract, and respiratory tract. Side effects include chest pain, gastrointestinal problems (nausea, diarrhea), headache, and fever. 

Meropenem. Meropenem is a carbapenam antibacterial with effects and spectrum similar to imipen- 

Polymyxin B. Polymyxin antibiotics are cationic compounds that are attracted to negatively charged phospholipids in the bacterial cell membrane. These drugs penetrate and disrupt the architecture and integrity of the surface membrane. Essentially, polymyxins act as detergents that break apart the phospholipid bilayer, which creates gaps in the bacterial cell wall, leading to the subsequent destruction of the bacteria.31 

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The mechanism of toxicity for aminoglycosides has not been fully explained and is therefore unclear. It is known that the drug attaches to a bacterial cell wall and is drawn into the cell via channels made up of a protein, porin. Once inside the cell, the aminoglycoside attaches to the 30S bacterial ribosomes. Ribosomes are the intracellular structures responsible for manufacturing proteins. This attachment either inhibits protein biosynthesis or causes the cell to produce abnormal, ineffective proteins. The bacterial cell cannot survive with this impediment. This explanation, however, does not account for the potent bactericidal properties of these agents, since other antibiotics that inhibit the synthesis of proteins (such as tetracycline) are not bactericidal. Recent experimental studies show that the initial site of action is the outer bacterial membrane. The cationic antibiotic molecules create fissures in the outer cell membrane, resulting in leakage of intracellular contents and enhanced antibiotic uptake. This rapid action at the outer membrane probably accounts for most of the bactericidal activity. 

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