Understanding the Different Types of Antibiotics and How They Work

By Global Health

Antibiotics are one of the most important discoveries in medical science. They are used to treat bacterial infections by either killing the bacteria or inhibiting their growth, allowing the body’s immune system to eliminate the pathogens more effectively.

But not all antibiotics are the same. There are several classes, each with distinct mechanisms of action, spectrums of activity, and clinical uses. The image below helps illustrate the classification of antibiotics commonly used in medicine today:

What Are Antibiotics?

Antibiotics are medications designed to treat infections caused by bacteria. They do not work against viruses (such as those causing colds or flu). Their action generally falls into two categories:

• Bactericidal: Kills bacteria directly (e.g., penicillins, cephalosporins)

• Bacteriostatic: Inhibits bacterial growth, allowing the immune system to take over (e.g., tetracyclines)

Different Classes of Antibiotics and Their Examples

1. Beta-Lactams

These include:

• Penicillins (e.g., ampicillin, amoxicillin): Often used for respiratory, skin, and urinary infections.

• Cephalosporins (e.g., cefuroxime, ceftriaxone): Effective for a broader range of infections, including pneumonia and meningitis.

• Carbapenems (e.g., imipenem, meropenem): Reserved for resistant or severe infections.

• Monobactams (e.g., aztreonam): Useful for patients allergic to penicillins.

  
  

2. Macrolides

(e.g., erythromycin, azithromycin): Often used in respiratory infections, skin infections, and for patients allergic to penicillin.

3. Fluoroquinolones

(e.g., ciprofloxacin, levofloxacin): Broad-spectrum antibiotics used for urinary tract infections, GI infections, and pneumonia.

4. Aminoglycosides

(e.g., gentamicin, tobramycin): Potent antibiotics used mainly in hospital settings for serious infections, especially Gram-negative bacteria.

5. Glycopeptides

(e.g., vancomycin, teicoplanin): Used to treat severe infections caused by Gram-positive bacteria, including MRSA.

6. Tetracyclines

(e.g., doxycycline): Broad-spectrum and commonly used for acne, respiratory infections, and Lyme disease.

7. Others

• Clindamycin: Often used for anaerobic infections or penicillin-allergic patients.

• Metronidazole: Targets anaerobic bacteria and protozoa.

• Trimethoprim: Frequently used for urinary tract infections.

Why It’s Important to Use Antibiotics Responsibly

Overuse and misuse of antibiotics have led to the rise of antibiotic-resistant bacteria—a serious global health threat. It’s vital to:

• Use antibiotics only when prescribed

• Complete the full course of treatment

• Never self-medicate or share antibiotics

Consult a Doctor Before Using Antibiotics

Antibiotics should only be used under the guidance of a qualified medical professional. Each infection requires proper evaluation to determine whether antibiotics are necessary, and if so, which type is appropriate. Misuse can lead to resistance, side effects, and ineffective treatment.

At Global Health, we are deeply committed to the well-being of our patients and to promoting health education in our communities. Understanding how antibiotics work and using them responsibly is a vital part of protecting both individual and public health.