Molecular Mechanisms of Resistance to Conventional Antibiotics in Bacteria

In the early years of the 20th century, the medical world was able to discover drugs that can eliminate microbial infections, and in the mid-twentieth century gradually began the clinical application of these drugs as antibiotics. Soon, however, scientists found that some microbes become resistant to these drugs and began attempts to identify new antibiotics. At the same time, microbes were also considering changes to escape the effects of antibiotics. The reality is that, like any other living creature, microorganisms, especially bacteria, adapt to their surroundings in order to survive. Therefore, the bacteria that were already affected by one or more antibiotics became resistant to them. Classically, drug resistance in bacteria is attributed to chromosomal mutations, but chiefly, it seems that it is associated with extra-chromosomal elements acquired from environmental bacteria. Accordingly, this review investigated the molecular mechanisms that lead to drug resistance in bacteria.