IMP-type metallo-β-lactamase (MBL) has become a more prominent enzyme, especially in Asia, since it was discovered in the 1990s in Japan. There are currently 88 variants of IMP-type enzymes and similar to other MBLs, IMP is commonly transferred between organisms, especially Gram-negative bacteria, via horizontal gene transfer. IMP−1 variant is the most commonly identified variant and can be resistant to even more antibiotics than KPC. IMP-type MBLs have been detected in more than ten species in Enterobacterales although Pseudomonas aeruginosa is the most frequent carrier of IMP-type enzymes worldwide.