Initially it was thought that the transfer of resistance genes in bacteria, mainly through conjugation and transduction by plasmids, phages and transposons is done. However, in 1995 by two scientists named Hall and Coli, another mechanism of transfer of resistance genes identified, by name integron elements. . Integrons are mobile genetic elements that are located in plasmids, chromosomes and transposons, carry the resistance genes that are within the gene cassette. Horizontal transfer of integron is the most successful dissemination of resistance genes and the emergence of strains with multiple resistances (MDR). Note that the resistance genes are located on integron and can be transferred from one strain to another side, so it’s important to identify the type of resistance genes.