A Review of Bacterial Antibiotic Resistance Genes and Their Removal Strategies from Wastewater

This review is intended to address the issues of unsafe disposal of antibiotics from various sources to the environment, its incomplete degradation, the resulting antibiotic resistance properties on microorganisms exposed to these antibiotics as well as some currently available techniques to remove both the antibiotic-resistant bacteria (ARBs) and antibiotic-resistant genes (ARGs) from water and wastewater systems. There is a linear correlation between the concentration of antibiotics in wastewater and the emergence of ARBs and the presence of ARGs. Wastewater treatment plant (WWTP) remains as one of the primary sources for ARB and ARG, even though the occurrence of ARBs and ARGs has also been reported in environment with no anthropogenic impact. Conventional removal techniques are available together with newer approaches that promises higher ARBs and ARGs removal efficiencies. Use of bioinformatic tools such as plasmidome is important to ensure sufficient information on ARGs, which may be directly mobilized and transferred to pathogens, can be obtained and analyzed. This review highlights the effects of continuous exposure to ARBs and ARGs present in the environment, notably wastewater, to human health. Various sources of antibiotics, classes of ARBs, and types of ARGs are adequately covered including highlights on recent reports from different countries. Conventional and newer approaches to remove ARBs and ARGs from wastewater were also elaborated to further assist reader’s understanding on the subject matter discussed.