Antibiotics deserve much of the credit for the dramatic increase in life expectancy around the world in the 20th century. Antibiotics have saved millions of lives, prevented amputations and blindness, advanced our abilities to perform surgery, enabled new cancer treatments, and protected the lives of our military men and women. Unfortunately, it is inevitable that over time bacteria develop resistance to existing antibiotics, making infections more difficult to treat. Antibiotics and other antimicrobials are the only drugs where extensive use leads to loss of benefit.
Microbes are very small living organisms, like bacteria. Most of the time, microbes are harmless and even helpful to humans, but some cause infections and disease. Drugs that we use to treat infections caused by microbes are called antimicrobial drugs. Antimicrobials are drugs that either kill or slow the growth of microbes (bacteria, fungi, viruses, and parasites). The most commonly known antimicrobial is antibiotics, which are used to treat bacterial infections. When the microbe develops resistance, i.e. a particular drug is no longer able to kill or slow the growth of the microorganism, this is called antimicrobial resistance (AMR). In some cases, the microorganism develops resistance to more than one drug, in which case the term multidrug resistance (MDR) is used. As a result of AMR, the antimicrobial drugs become ineffective and the infections persist in the body, which in turn increases the chance of spreading the infection to others. This resistance has the potential to affect people at any stage of life, as well as healthcare, veterinary, and agriculture industries. For example, without effective antibiotics, the success of any major surgery and cancer chemotherapy is compromised. The cost of healthcare for patients with resistance infections is much higher than non-resistant infections because the illness will have a longer duration, additional testing is required, and more expensive drugs must be used. New resistance mechanisms are emerging and spreading globally, which threatens our ability to treat infectious diseases, leading to prolonged illness, disability, and death, making AMR one of the worlds' most urgent public health problems.