Hospital Wastewater Case Study

1.0 Introduction
Wastewater refers to any water whose quality has been compromised by human activities. It includes liquid waste discharged from domestic homes, agricultural commercial sectors, pharmaceutical sectors, and hospitals (Fekadu et al., 2015). Hospital wastewater (HWW) can contain hazardous substances, such as pharmaceutical residues, chemical hazardous substances, pathogens, and radioisotopes. Due to these substances, hospital wastewater can represent a chemical, biological, and physical risk for public and environmental health (Carraro et al., 2017). Nevertheless, very frequently there are no legal requirements for hospital effluent treatment prior to its discharge into the municipal collector or directly onto
Gram-negative pathogens such as Escherichia coli and Klebsiella pneumoniae have shown increased resistance to a variety of antibiotics typically used in the treatment of infections and diseases caused by these bacteria (Izadpanah and Khalili, 2015; Santajit and Indrawattana, 2016). Hospital wastewater is considered a hot spot for AR as a consequence of receiving a cocktail of antibiotic compounds, disinfectants, and inputs of bacterial sheddings and metabolized drugs from patient excrement, which potentially contain multidrug-resistant (MDR) pathogens (Chang et al., 2010; Galvin et al., 2010; Chagas et al., 2011). As such, hospital wastewaters provide an environment for the exchange of antibiotic resistance genes (ARGs) between clinical pathogens and other environmental bacteria in recipient sewers, which could result in broader epidemiological consequences extending beyond the hospital setting (Le et al.,
However, those studies used PCR, pulsed-field gel electrophoresis (PFGE), and culture methods to track organisms and antimicrobial resistance genes. WGS was often performed only on a small number of isolates and plasmids in these studies limiting the genomic resolution of the analysis. Additionally, there have been limited studies comparing plasmid diversity among hospitral effluent samples. Furthermore, investigation of antibiotic resistance in microbial communities based solely on cultivable bacteria makes the assessment results unrepresentative and biased (Zhang et al., 2011). Therefore, a metagenomic approach is needed for a more comprehensive overview of plasmids residing in hospital effluent microorganisms. Metagenomics, combined with the Search Engine for Antimicrobial Resistance (SEAR), allows the resolution of full-length ARGs from environmental samples of unknown composition, thus providing an excellent method for investigating the resistome (Rowe et al., 2017). However, it is important when assessing the impact of anthropogenic activities on the resistome that one technique is not used in isolation but rather that