What are the classes of beta-lactam (β-lactam) antibiotics?

From the Guidelines

Beta-lactam antibiotics are classified into several major groups: penicillins, cephalosporins, carbapenems, and monobactams. The classification of beta-lactam antibiotics is based on their chemical structure and mechanism of action. The main classes of beta-lactam antibiotics include:

• Penicillins, which are further divided into natural penicillins (penicillin G, penicillin V), aminopenicillins (ampicillin, amoxicillin), antipseudomonal penicillins (piperacillin, ticarcillin), and penicillinase-resistant penicillins (methicillin, nafcillin, oxacillin, dicloxacillin) 1.
• Cephalosporins, which are divided into generations: first-generation (cefazolin, cephalexin), second-generation (cefuroxime, cefoxitin), third-generation (ceftriaxone, cefotaxime, ceftazidime), fourth-generation (cefepime), and fifth-generation (ceftaroline, ceftolozane) 1.
• Carbapenems, which include imipenem, meropenem, ertapenem, and doripenem 1.
• Monobactams, with aztreonam being the only clinically available monobactam 1. Beta-lactamase inhibitors like clavulanic acid, sulbactam, tazobactam, and avibactam are often combined with beta-lactams to overcome bacterial resistance 1. All beta-lactams share a common four-membered beta-lactam ring in their structure and work by inhibiting bacterial cell wall synthesis by binding to penicillin-binding proteins, ultimately causing bacterial cell death 1. The different classes vary in their spectrum of activity, resistance to beta-lactamases, and clinical applications 1. It is essential to note that the classification and use of beta-lactam antibiotics can vary depending on the specific clinical context and local resistance patterns 1. In general, the choice of beta-lactam antibiotic depends on the type of infection, the suspected or confirmed causative pathogen, and the patient's individual characteristics, such as renal function and allergy history 1. The most recent and highest quality study 1 provides a comprehensive overview of the classification and use of beta-lactam antibiotics, and it is essential to consult this study for the most up-to-date information on this topic.

From the FDA Drug Label

The bactericidal activity of imipenem results from the inhibition of cell wall synthesis. Its greatest affinity is for penicillin binding proteins (PBPs) 1A, 1B, 2,4,5 and 6 of Escherichia coli, and 1A, 1B, 2,4 and 5 of Pseudomonas aeruginosa. Imipenem has a high degree of stability in the presence of beta-lactamases, both penicillinases and cephalosporinases produced by Gram-negative and Gram-positive bacteria.

The classes of beta-lactam antibiotics include:

• Penicillins: such as penicillinases
• Cephalosporins: such as cephalosporinases
• Monobactams: such as aztreonam 2
• Carbapenems: such as imipenem 3

From the Research

Classes of Beta-Lactam Antibiotics

The classes of beta-lactam antibiotics include:

• Penicillins 4, 5
• Cephalosporins 4, 5, 6, 7
• Carbapenems 4, 5, 6, 7
• Monobactams 4, 5, 6, 7
• Penems 4
• Cephamycins 6

Sub-Classes of Penicillins

Sub-classes of penicillins include:

• Penicillinase-resistant penicillins 5
• Extended-spectrum penicillins 5

Beta-Lactamase Inhibitors

Beta-lactamase inhibitors are used in combination with beta-lactam antibiotics to overcome resistance mechanisms, and include:

• Clavulanate 8
• Sulbactam 8
• Tazobactam 8