Antibiotic resistant bacteria and genes (ARB and ARG) in water and sewage treatment units: A review

Microorganisms have historically coexisted with humans, animals, and the environment in a natural way. Like any other living being, microorganisms are subjected to environmental pressures that can eventually extinguish or strengthen their existence. In recent years, the emergence of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) has raised an alert about their influence on human and animal health. In addition to ARBs found in nosocomial environments, recent studies point to the environment as an auxiliary hotspot for the spread of antimicrobial resistance. In this sense, this review covers research that investigated ARB and ARG in E. coli and Salmonella, occurrence and potential environmental reservoirs for the spread of antimicrobial resistance, as well as a discussion on how bacterial resistance affects public health, the detection and treatment methods currently employed to reduce or remove this pollutant from water treatment plants (WTP) and sewage treatment plants (WWTP). The results indicated that the great increase in bacterial resistance may be linked, among other reasons, to repetitive contact with residual concentrations of antibiotics present in the environment, causing the bacteria to suffer from selective pressure and if resistant to one or more antibiotics. Thus, public health is compromised, since commonly used antibiotics are often ineffective in treating disease-resistant pathogenic bacteria. From this perspective, studies have shown the importance of consistent detection methods, which allow the tracking and analysis of sources of antimicrobial resistance on a global scale, in addition to the need to improve advanced treatment to reduce the ARG and ARB of WTPs and WWTPs. The first two sections of this review article present an overview of the problems related to the occurrence and dissemination of antimicrobial resistance (AMR) in bacteria, with a focus on E. coli and Salmonella, identified by the WHO as bacteria of global priority for surveillance. The third section addresses environmental and public health issues related to AMR. Section 4 addresses analytical methods for detecting antibiotic-resistant bacteria (E. coli and Salmonella) in the most diverse types of samples. In the subsequent chapter, the application of technologies for the removal/reduction of ARB and ARG as environmental contaminants in water and wastewater is discussed. Finally, future perspectives and gaps to be faced by this field of research are presented. A critical analysis of the authors is presented in each section.