Beta Lactam Antibiotics

What is Beta Lactam Antibiotics?

Antibiotics with a beta-lactam ring in their chemical structure are known as -lactam antibiotics (beta-lactam antibiotics). Penicillins, cephalosporins, are examples of beta-lactam antibiotics. These medications are effective against a wide range of gram-positive, gram-negative, and anaerobic bacteria.

Antibiotics known as beta-lactams are one of the most often prescribed medication groups, with a wide range of clinical applications. Their introduction, which began in the 1930s, revolutionised the fight against bacterial infectious illnesses.

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Beta Lactam Antibiotics Classification

For β-lactamases, there are two widely accepted classification schemes: the first is based on amino-acid sequence classification, while the second is based on functionality. Ambler classified β-lactamases into four groups (Class A–D) based on sequence similarities in 1980. The serine ester hydrolysis mechanism is used by classes A, C, and D, whereas class B -lactamases, commonly known as metallo-lactamases, use a zinc ion to catalyse the reaction.

The functional classification approach yielded three primary groups: Group 1 cephalosphorinases (Class C), Group 2 serine-lactamases (Class A and Class D), and Group 3 metallo-lactamases (Class B), each of which is further subdivided into subgroups.

  • Penicillins
  • Cephalosporins
  • Monobactams
  • Carbapenems

Beta Lactam Antibiotics Examples

Penicillin – These antibiotics have a nucleus of 6-animopenicillanic acid (lactam plus thiazolidine) ring with various ringside chains (most of which end in -cillin). Natural penicillins, beta-lactamase-resistant agents, aminopenicillins, carboxypenicillins, and ureidopenicillins are all members of this group.

Cephalosporins – Cephalosporins are beta-lactam antimicrobials that are used to treat gram-positive and gram-negative bacteria infections. Cephalosporins come in five generations and are effective against skin infections, resistant bacteria, meningitis, and other infections.

Monobactams – Monobactams are bacterially generated monocyclic -lactam antibiotics. Unlike most other -lactams, the -lactam ring is not bonded to another ring. Monobactams are only effective against Gram-negative bacteria that are aerobic.

Carbapenems – Carbapenems are a type of beta-lactam antibiotic that may kill gram-positive and gram-negative bacteria in both aerobic and anaerobic environments. The first carbapenem, thienamycin, was found in 1976.

Mechanism of Resistance

Beta-lactam resistance is an alarming and developing problem that poses a public health threat. It mostly affects Streptococcus pneumoniae and single gram-negative bacteria like Pseudomonas aeruginosa. With antibiotic resistance on the rise, it makes sense to investigate causes of resistance, since this can help determine which treatments to give in certain settings and how to combat the problem. Although the development of beta-lactamases is the most common mechanism for bacterial resistance to beta-lactams, other processes are also implicated.

The methods of resistance are listed below.

  • The formation of beta-lactamases inactivates the bacteria.
  • Reduced penetration to the target site (e.g., Pseudomonas aeruginosa resistance)
  • PBPs at the target location are altered (e.g., penicillin resistance in pneumococci)
  • Through particular pumping processes, efflux from the periplasmic region is achieved.

Adverse Effects of Beta Lactam Antibiotics

In comparison to other types of drugs, beta-lactams are generally safe and well tolerated. [8] Allergic responses, which range from 0.7 percent to 10%, are the most common side effects. These responses can occur with any penicillin dose form and are typically maculopapular rashes, with anaphylaxis reported in 0.004 to 0.015 percent of individuals. Beta-lactams can cause a variety of adverse effects in addition to allergic reactions.

  • Penicillin G and piperacillin have also been linked to a lack of hemostasis due to platelet aggregation problems.
  • A benzathine penicillin G IV injection has been linked to cardiorespiratory arrest and mortality.
  • Cephalosporins have been linked to a small number of cases of bone marrow depression, including granulocytopenia.
  • Some cephalosporins are nephrotoxic, and renal tubular necrosis is linked to them. By displacing bilirubin from albumin, ceftriaxone can cause jaundice in newborns.
  • Due to its high affinity for biliary calcium, it can potentially cause biliary pseudolithiasis.
  • At large doses or in patients with renal failure, cefepime causes encephalopathy and nonconvulsive status epilepticus.
  • When given in high doses to patients with CNS lesions or renal failure, imipenem might cause seizures.

Frequently Asked Questions on Beta Lactam Antibiotics


Which are beta-lactam antibiotics?

β-Lactam antibiotics have a β-lactam ring in their molecular structure. They include penicillins, cephalosporins, monobactams, and carbapenems. They are bactericidal antibiotics that bind covalently to and inhibit penicillin binding proteins (PBPs).


Why is it called beta-lactam?

Any substance that can destroy or inhibit the growth of bacteria and similar microorganisms. β-lactam: A β-lactam (beta-lactam) ring is a four-membered lactam. A lactam is a cyclic amide. It is named as such, because the nitrogen atom is attached to the β-carbon relative to the carbonyl.


What is the classification of beta-lactam antibiotics?

β-lactams are classified according to their core ring structures. β-lactams fused to saturated five-membered rings: β-lactams containing thiazolidine rings are named penams. β-lactams containing pyrrolidine rings are named carbapenams.


Is penicillin a beta-lactam antibiotic?

Beta-lactam antibiotics include penicillins, cephalosporins, and related compounds. As a group, these drugs are active against many gram-positive, gram-negative, and anaerobic organisms.


Why are they called beta-lactam antibiotics?

A beta-lactam (β-lactam) ring is a four-membered lactam. A lactam is a cyclic amide, and beta-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl.


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