Cephem

Cephem is a class of beta-lactam antibiotics that includes cephalosporins, cephamycins, oxacephems, and carbapenems. These antibiotics are widely used in the treatment of bacterial infections due to their broad spectrum of activity.

History

The first cephem antibiotic, cephalothin, was discovered in 1964. Since then, several generations of cephem antibiotics have been developed, each with improved properties and broader spectrum of activity.

Structure

Cephem antibiotics share a common beta-lactam ring structure, which is responsible for their antibacterial activity. The beta-lactam ring is highly reactive and binds to penicillin-binding proteins (PBPs) in the bacterial cell wall, inhibiting cell wall synthesis and leading to cell death.

Mechanism of Action

Cephem antibiotics work by inhibiting the synthesis of the bacterial cell wall. They bind to PBPs in the bacterial cell wall, preventing the cross-linking of peptidoglycan chains, which are essential for bacterial cell wall strength and rigidity. This leads to cell lysis and death.

Resistance

Bacterial resistance to cephem antibiotics can occur through several mechanisms, including the production of beta-lactamases, which are enzymes that hydrolyze the beta-lactam ring, rendering the antibiotic ineffective. Other mechanisms of resistance include alterations in PBPs and efflux pumps.

Clinical Use

Cephem antibiotics are used to treat a wide range of bacterial infections, including respiratory tract infections, urinary tract infections, skin infections, and sepsis. The choice of cephem antibiotic depends on the type of infection, the susceptibility of the bacteria, and the patient's clinical condition.

Side Effects

Common side effects of cephem antibiotics include allergic reactions, diarrhea, nausea, and vomiting. Serious side effects can include Clostridium difficile infection, kidney damage, and blood disorders.

See Also

• Beta-lactam antibiotics
• Penicillin-binding proteins
• Beta-lactamases

Cephem

• 
  Cephalosporin core structure
• 
  Cephamycin core structure