AMR refers to the phenomenon of microorganisms to survive under the exposure to antimicrobials. Some AMR genes can be transmitted horizontally, and can therefore be transferred to other bacteria, so called AMR spreading. Antimicrobial pressure leads to the selection of resistant strains. Therefore, the overuse of antimicrobials leads to the spread of AMR bacteria, and proper usage of antimicrobials is very important to prevent the AMR spread.

Since the discovery of penicillin, the first commercialized antimicrobials, various antimicrobials have been developed, and they have saved life from infectious diseases. However, antimicrobial usage was followed by AMR. Microorganisms are constantly searching for ways to survive under antimicrobial pressure by acquiring the AMR genes from other bacteria, thereby leading to a global threat to public health. Worldwide, AMR-related death is expected to reach 700,000 per year (approximately 20,000 in the USA) and 10 million by 2050. If we fail to address the challenge of AMR, the pre-antimicrobial era would come soon.