Role of integrons in antimicrobial resistance: A review

Antibiotic resistance in bacteria still remains one of the leading concerns in global public health. Horizontal transfer of resistance genes is considered to be a major cause to facilitate the rapid spread of antibiotic resistance in microbes. In recent years, the role of integrons as mobile genetic elements playing a central role in horizontal transfer of antibiotic resistance have been well studied and documented. Nevertheless, up to date, most of the available investigations and studies on integron had focused on class 1 integrons of Gram-negative microorganisms. In the last decade, class 4 integrons (also known as super integrons) has been considered a major concern in antimicrobial resistance, as well as, a significant factor in bacterial genome evolution; however, most reports had been limited to Vibrio. Thus, this review is aimed at summarizing the occurrence and prevalence of integrons in bacterial isolates, with the focus on class 1 integron within Gram-positive bacteria, class 2 and 3 integrons.   Key words: Antibiotic resistance, mobile genetic element, Class 1 integron, Class 2 integron, Class 3 integron, Gram-positive bacteria.