List of β-lactam antibiotics

β-lactam antibiotics are a broad class of antibiotics that include penicillin derivatives, cephalosporins, monobactams, and carbapenems. They are characterized by a β-lactam ring in their chemical structure and are known for their ability to inhibit bacterial cell wall synthesis.

Penicillins

Penicillins are the oldest β-lactam antibiotics and are derived from the fungus Penicillium. They are divided into two groups: natural penicillins and synthetic penicillins. Natural penicillins, such as penicillin G and penicillin V, are effective against gram-positive bacteria. Synthetic penicillins, such as amoxicillin and ampicillin, have a broader spectrum of activity.

Cephalosporins

Cephalosporins are a large group of β-lactam antibiotics that are divided into five generations based on their spectrum of activity. First-generation cephalosporins, such as cefazolin and cephalexin, are primarily effective against gram-positive bacteria. Later generations, such as ceftazidime and cefepime, have a broader spectrum of activity and are effective against more types of bacteria.

Monobactams

Monobactams are a class of β-lactam antibiotics that contain a single β-lactam ring. The only monobactam currently in clinical use is aztreonam, which is primarily used to treat infections caused by gram-negative bacteria.

Carbapenems

Carbapenems are a class of highly potent β-lactam antibiotics that are effective against a wide range of bacteria. They include drugs such as imipenem, meropenem, and ertapenem. Due to their broad spectrum of activity, they are often reserved for severe or high-risk infections.

Mechanism of Action

β-lactam antibiotics work by inhibiting the synthesis of the bacterial cell wall. They do this by binding to penicillin-binding proteins (PBPs), which are enzymes involved in the final stages of cell wall synthesis. This prevents the formation of the cell wall, leading to bacterial cell death.

Resistance

Resistance to β-lactam antibiotics can occur through several mechanisms, including the production of β-lactamase enzymes that break down the antibiotic, changes in PBPs that prevent the antibiotic from binding, and changes in the bacterial cell wall that prevent the antibiotic from reaching its target.