Only a few decades ago, antibiotics were considered to be wonder drugs because they worked so well to cure deadly diseases. Ironically, though, many antibiotics have become less effective, precisely because they have worked so well and have been used so often.
It's not just antibiotics (antibacterials), Antimicrobial resistance (AMR) threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi.
Microorganisms that develop antimicrobial resistance are sometimes referred to as "superbugs".

The golden age of antibiotics proved to be a short-lived one. During the past few decades, many strains of bacteria have evolved resistance to antibiotics.
This evolution has accelerated because of,
1. Overuse of antibiotics.
2. Use of preventive antibiotics on livestock and crops.
3. use antibiotics to treat viral infections. Antibiotics work on bacterial infections not viral infections.
4. Using mild doses of an antibiotic over long periods of time; A high-dosage prescription is preferable.

Common examples are:
- MRSA - methicillin-resistant Staphylococcus aureus. in 2004, 63% of all reported staph infections in the United States were caused by MRSA.
- Neisseria gonorrhoeae - Today, more than 24 percent of gonorrheal bacteria in the U.S. are resistant to at least one antibiotic.
- Pseudomonas aeruginosa poses a greater threat because it has certain biological features that make it more readily resistant to antibiotics than MRSA
- Globally, 480 000 people develop multi-drug resistant TB each year.
- Klebsiella pneumoniae - In some countries, because of resistance, carbapenem antibiotics do not work in more than half of people treated for K. pneumoniae infections.
- E. coli - There are countries in many parts of the world where treatment of urinary tract infections with fluoroquinolone antibiotics is now ineffective in more than half of patients.
- P. falciparum malaria