Integrons and antibiotic resistance genes in water-borne pathogens: threat detection and risk assessment

Antibiotic-resistant genes (ARGs) are regarded as emerging environmental pollutants and pose a serious health risk to the human population. Integrons are genetic elements that are involved in the spread of ARGs amongst bacterial species. They also act as reservoirs of these resistance traits, further contributing to the development of multi-drug resistance in several water-borne pathogens. Due to inter- and intra-species transfer, integrons are now commonly reported in important water-borne pathogens such as Vibrio, Campylobacter, Salmonella, Shigella, Escherichia coli and other opportunistic pathogens. These pathogens exhibit immense diversity in their resistance gene cassettes. The evolution of multiple novel and complex gene cassettes in integrons further suggests the selection and horizontal transfer of ARGs in multi-drug resistant bacteria. Thus, the detection and characterization of these integrons in water-borne pathogens, especially in epidemic and pandemic strains, is of the utmost importance. It will provide a framework in which health authorities can conduct improved surveillance of antibiotic resistance in our natural water bodies. Such a study will also be helpful in developing better strategies for the containment and cure of infections caused by these bacteria.