No abstract

Since the COVID-19 pandemic started, there has been much speculation about how COVID-19 and antimicrobial resistance may be interconnected. In this study, untreated wastewater was sampled from Hospital A designated to treat COVID-19 patients during the first wave of the COVID-19 pandemic alongside Hospital B that did not receive any COVID-19 patients. Metagenomics was used to determine the relative abundance and mobile potential of antibiotic resistant genes (ARGs), prior to determining the correlation of ARGs with time/incidence of COVID-19. Our findings showed that ARGs resistant to macrolides, sulfonamides, and tetracyclines were positively correlated with time in Hospital A but not in Hospital B. Likewise, minor extended spectrum beta-lactamases (ESBLs) and carbapenemases of classes B and D were positively correlated with time, suggesting the selection of rare and/or carbapenem-resistant genes in Hospital A. Non-carbapenemase bla VEB also positively correlated with both time and intI1 and was copresent with other ARGs including carbapenem-resistant genes in 6 metagenome-assembled genomes (MAGs). This study highlighted concerns related to the dissemination of antimicrobial resistance (AMR) during the COVID-19 pandemic that may arise from antibiotic use and untreated hospital wastewater.

This study characterizes a total of 21 wastewater samples collected from Al Amal hospital, and aims to determine if untreated hospital wastewater may impose a potentially detrimental impact on the downstream municipal biological wastewater treatment process. By means of solid phase extraction and liquid chromatography with tandem mass spectrometry (LC-MS/MS), chemical contaminants in these wastewater samples were determined in a non-targeted manner. In-silico characterization for the mutagenicity and reactive oxygen species (ROS) producing capabilities was performed by checking against database and literature. However, majority of the chemical contaminants have no prior information available and remain uncharacterized for both traits. Instead, in-vitro mutagenicity tests by means of Ames test showed that majority of the samples were non-mutagenic except for 5 samples that imposed mutagenic effect at high concentrations of >×10. In-vitro tests to determine for intracellular ROS production further showed that one of the mutagenic samples collected on Jun-22 positively induce ROS production and subsequently increased horizontal gene transfer via natural transformation. The findings in this study suggest that a specialty hospital like Al Amal does not frequently contribute mutagenic compounds and ROS to the wastewater streams, and in instances where it contributed positively, would require a high concentration to do so. Hence in general, wastewater streams from a specialty hospital like Al Amal may be unlikely to significantly perturb the downstream environment.

The environmental cycling of antibiotic-resistant blaCTX-M-15-producing E. coli following release from wastewater treatment plants is a major public health concern. This study aimed to (i) assess the impact of sediment concentrations on the rate of their inactivation following release from human wastewater into freshwater, and (ii) simulate their subsequent dispersal to the nearby coastline during a “worst-case” event where heavy rainfall coincided with high spring tide in the Conwy Estuary, North Wales. Freshwater microcosms of low, medium and high turbidity were inoculated with blaCTX-M-15 -producing E. coli, then exposed to ultraviolet (UV) radiation. Typical regional wintertime exposure to UV was found to be insufficient to eradicate E. coli, and in highly turbid water, many bacteria survived simulated typical regional summertime UV exposure. Modelling results revealed that blaCTX-M-15-producing E. coli concentrations reduced downstream from the discharge source, with ~ 30% of the source concentration capable of dispersing through the estuary to the coast, taking ~36 h. Offshore, the concentration simulated at key shellfisheries and bathing water sites ranged from 1.4% to 10% of the upstream input, depending on the distance offshore and tidal regime, persisting in the water column for over a week. Our work indicates that the survival of such organisms post-release into freshwater is extended under typical wintertime conditions, which could ultimately have implications for human health.