Wastewater monitoring - passive sampling for the detection of SARS-CoV-2 and antibiotic resistance genes in wastewater.

As a lesson learned from the COVID-19 pandemic, wastewater-based epidemiology was recognised and used as an important method for surveillance and early detection of SARS-CoV-2. As a result, consideration of wastewater as a source of public health information has gained new prominence, and there is consensus that similar approaches can be used to detect the spread of other viral pathogens or antimicrobial resistance (AMR) in populations. However, the implementation of wastewater monitoring poses challenges in terms of obtaining representative and meaningful samples. In particular, it is difficult to sample small catchments, critical facilities (e.g. hospitals) or low-income countries where the use of automatic water samplers is not possible or the samplers are not available. To overcome these problems, this study developed a low-cost and easy-to-use passive sampler based on activated carbon as an adsorbent with a corresponding elution/extraction protocol that allows the detection of viruses and antibiotic resistance genes in wastewater. Monitoring of SARS-CoV-2 with these passive samplers at the influent of a wastewater treatment plant over a period of 1.5 months showed a positive correlation with monitoring with 24-h composite samples in the catchment area. Analysis of the nucleic acid extracts for antibiotic resistance genes showed the presence of clinically relevant carbapenemase genes such as bla and bla in the wastewater samples, with these genes being detected more reliably by the passive samplers than in the 24-h composite samples. This study therefore demonstrated that passive samplers provide reproducible SARS-CoV-2 RNA and antibiotic resistance gene signals from wastewater and a time-integrated measurement of the sampled matrix with high sensitivity.