Antibiotic-resistant bacteria and antibiotic resistance genes profile in wastewater treatment plants by using genomic approaches

Abstract

Abstract Antibiotic resistance is recognized as one of the most important serious public health problem. Together with antibiotics, antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are introduced into wastewater. Wastewater treatment plants (WWTPs) are considered as a source antibiotic resistance dissemination in the environment due to horizontal transfer of ARGs among different microorganisms. In fact, genes conferring resistance to all classes of antibiotics together with mobile genetic elements like plasmids, transposons, bacteriophages, and integrons carrying ARGs are detected in WWTPs in different countries. Metagenomic analyses have shown that genera such as Enterococcus or Escherichia, often targeted in antibiotic resistance culture-dependent studies in WWTPs, are not detected among the most abundant groups. Proteobacteria followed by Firmicutes and Actinobacteria and members of the genera Aeromonas, Bacillus, Lysinibacillus, Microbacterium, Providencia, and Staphylococcus were predominant bacteria observed in both influent and effluent of WWTP samples. Increasing evidence has indicated that sewage treatment plants serve as essential reservoirs for tetracycline-resistant bacteria and resistance genes (tet) to the environment. Proper treatment of wastewater is essential to prevent the spread of ARB and ARGs into the environment prior to its discharge into rivers, lakes, or sewage systems. The accelerating development of antibiotic resistance among bacteria is a challenging problem, requiring improvement in treatment processes to the next decade.