Colistin and carbapenems as last-resort antibiotics: Challenging environmental impacts and analytical methods

Abstract

Colistin and carbapenems, vital last-resort antibiotics against severe bacterial infections unresponsive to common drugs, pose a threat when resistance develops as it may leads to complete antibiotic ineffectiveness. The estimation and quantification of colistin and carbapenems in environmental samples is challenging due to their low concentrations, complex structures, stability issues, and potential interference from other substances. Despite known side-effects, the biological impacts of their residues recirculated in the environment has not yet been evaluated. This review provides an in-depth analysis of these two critical drugs by exploring their chemical and biological properties and current detection. This is based on 41 analytical studies on their quantitation methods, with 7 studies being from environmental matrices and the rest being from biological matrices. Reverse-phased chromatography and high-performance liquid chromatography tandem mass spectrometry are the main instruments due to their polar nature. We also discuss the growing challenges associated with their release into environmental settings. We focus on the environmental entry pathways of these antibiotic residues, as well as the development of resistance. These antibiotics primarily enter the environment through runoff from hospitals and agricultural sites, leading to their accumulation in wastewater, soil, and natural water bodies. This environmental exposure is particularly of concern due to the potential for resistance development. The spread of resistance genes is a complex process, often involving mechanisms like horizontal gene transfer, which are facilitated by the presence of these antibiotic residues in the environment. Further research is crucial in understanding the environmental release of these critical antibiotics, the analytical methods of their quantifycation in environmental settings, and their role in the dissemination of antimicrobial resistance.