Final answer:
Penicillins and cephalosporins are broad-spectrum antibiotics essential for treating bacterial infections due to their low toxicity and ability to inhibit cell wall synthesis. While penicillins are more effective against gram-positive bacteria, cephalosporins have increased resistance to β-lactamases, making them effective against a broader range of bacteria, including more gram-negative bacteria.
Step-by-step explanation:
Penicillins and Cephalosporins
Penicillins and cephalosporins are broad-spectrum antibiotics that play a crucial role in treating various bacterial infections due to their low toxicity and wide range of action. Penicillins such as penicillin, amoxicillin, and piperacillin tazobactam, target bacterial cell wall synthesis and are effective against both gram-positive and some gram-negative bacteria. Penicillin G, one of the earliest used penicillins, is not stable in the acidic pH of the stomach, which led to the development of more acid-stable oral penicillins like penicillin V and amoxicillin.
Cephalosporins, also containing a ß-lactam ring, have a structural chemical difference that provides increased resistance to enzymatic inactivation by ß-lactamases, making them effective against a broader range of gram-negative bacteria. These antibiotics originated from the fungus Cephalosporium acremonium and have evolved into several generations, with increasing spectrum of activity from first-generation to the more broad-spectrum fourth- and fifth-generation cephalosporins.
Cephalosporins and penicillins are part of the larger group of ß-lactam antibiotics, characterized by the presence of a ß-lactam ring essential for their antibacterial activity. This ring structure mimics the peptidoglycan subunit that crosslinking enzymes, also known as penicillin-binding proteins, recognize during cell wall synthesis, thus inhibiting bacterial growth and leading to cell lysis. Resistance to β-lactam antibiotics can occur due to the production of β-lactamases by bacteria, necessitating the use of β-lactamase inhibitors or the development of resistant antibiotics such as the cephalosporins.