Stephen I. Feller , 2025-04-30 21:17:00
April 30, 2025
2 min read
Key takeaways:
- Hospital wastewater analysis showed that clinical respiratory viruses and other pathogens appear to be accurate.
- The accuracy of antimicrobial resistance genes did not align with clinical cases in the hospital.
ORLANDO — Wastewater surveillance is generally conducted at local, state and national population levels, but a study presented at SHEA Spring suggested it could be useful for health care facilities to conduct themselves.
Guillermo Rodriguez–Nava, MD, third-year infectious diseases fellow at Stanford University, who presented the study at SHEA, told Healio that he is only aware of a handful of institutions in the United States that conduct their own wastewater surveillance and whether more should be doing so was one of the questions the study was aiming to answer.
A wastewater surveillance trial program at Stanford Hospital suggested the effort may be worth it for larger institutions, researchers said at SHEA, but challenges to accuracy still remain. Image: Adobe Stock
“It may depend on the hospitals and what they’re trying to do,” Rodriguez said. “For respiratory viruses, perhaps community wastewater is good enough as usual, but for antibiotic resistant genes, maybe some hospitals … [should] try to do it every 1 or 2 months to get an idea of what’s going on in terms of antimicrobial resistance.”
Early in the COVID-19 pandemic, the CDC started using wastewater surveillance to detect upticks in SARS-CoV-2 cases. Several studies have shown that the surveillance method can confirm spikes in clinical cases of COVID-19, influenza and RSV during respiratory virus season and a 2024 study showed that detection of highly pathogenic H5N1 avian influenza could have offered experts an early warning of its spread.
Rodriguez and colleagues, in a pilot study at Stanford Hospital, deployed a Teledyne ISCO 5800 wastewater autosampler to collect samples from the final hospital outflow point before the water merged with the community sewer system to determine if they could detect circulating pathogens among all people in the facility.
The researchers programmed the sampler to collect 1,000 mL of water per week at a rate of 15 mL every 151 minutes. They processed the samples within 48 hours of collection, separating solids using centrifugation, and conducted nucleic acid extraction and droplet digital PCR testing targeting a set of pathogens.
The hospital wastewater nucleic acid concentrations were then compared with the number of positive cultures at the hospital during the same time period and with community wastewater data.
According to Rodriguez, the researchers faced several challenges, including the location of the wastewater outflow and the size of the autosampler.
The samples paralleled the number of clinical cases of infection and were similar to community wastewater trends, he said. He noted, however, that while mecA showed some alignment, most antimicrobial genes, including vanA, and carbapenemase genes, including KPC, NDM, OXA-48 and VIM, showed limited alignment with clinical cases at the hospital.
Hospital wastewater also had a higher concentration of resistant genes than community wastewater, he said.
Overall, Rodriguez said the ability to track clinical respiratory virus trends through facility wastewater could be useful, but that determining trends for antimicrobial resistance is more challenging because of a range of potential additional influences. These could include the number of colonized patients, bacterial load in the hospital’s sewage system, hospital antimicrobial use and drug residues in the water.
When it comes to individual facilities and health systems making a decision on wastewater surveillance, Rodriguez said it likely comes down to the facility itself, their size and their needs, as well as changes to public health funding and programs — which often pay for these types of efforts.
“It depends,” Rodriguez said. “Some facilities may benefit from it, perhaps some would not. We’re lucky enough that we are in an area where there is a lot of biotech companies to invest in this. So, perhaps this can be outsourced to the industry side to distribute costs to private sources rather than the government.”
For more information:
Guillermo Rodriguez–Nava, MD, can be reached at guiro@stanford.edu.
Sources/Disclosures
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Rodriguez Nava G. Abstract 231. Presented at: SHEA Spring 2025; April 27-30, 2025; Orlando.
Disclosures:
Rodriguez reports no relevant financial disclosures.
