Lab Matters Fall 2024 | Page 140

APHL 2024 POSTER ABSTRACTS

Wastewater-based Surveillance of Carbapenemaseresistant Genes

M . Schussman 1 , S . McLellan 1 , K . Janssen 2 , E . Doolittle 2 , G . Knuth 2 , University of Wisconsin-Milwaukee 1 , Wisconsin State Laboratory of

Hygiene 2

Wastewater-based surveillance is a rapidly advancing field that has gained popularity over the COVID-19 pandemic . Worldwide there are almost 5,000 sites publishing wastewater surveillance data for SARS-CoV-2 levels that have been used to rapidly and holistically monitor disease spread . Now that laboratories have methods in place , new targets are being explored that can expand the wastewater surveillance system capabilities . We have been investigating surveillance of antimicrobial resistance ( AR ). AR has been declared one of the greatest global public health challenges of our time , according to the CDC , with more than 2.8 million antibiotic-resistant infections occurring in the United States alone . AR wastewater surveillance can provide rapid identification and characterization of resistant bacteria , help communities understand trends and monitor interventions , all of which are goals of the US National Action Plan for Combating Antibiotic-Resistant Bacteria . In this study we quantified the abundance of six carbapenem-resistant genes including bla-KPC , bla-NDM , bla-IMP-1 , bla-VIM , bla-OXA48 and bla- OXA24 / 40 ( which are not distinguished by the assay ) across 70 samples using digital droplet polymerase chain reactions ( ddPCR ). We analyzed two wastewater treatment plants ( WWTP ) that together service the entirety of Milwaukee . The samples were collected biweekly over the span of a year , from September 2022 to August 2022 . Samples were additionally analyzed for humanspecific Bacteroides ( HF183 ) and human-specific Lachnospiraceae ( Lachno3 ), which are present in the human gut microbiome and represent a method to track human fecal inputs . We also quantified the organisms that frequently carry these genes including E . coli ( uidA gene marker ), Acinetobacter baumannii and Klebsiella pneumoniae ( KHE marker ).

We found all six AR genes were present in both WWTPs . Bbla-KPC , bla-OXA48 and bla-OXA24 / 40 were quantified in 100 % of the sample in mean concentrations ranging up to 4.9E + 07 copies per liter for KPC , 1.2E + 06 for bla-OXA24 / 40 and 4.5E + 05 for bla- OXA48 . Bla-NDM , bla-IMP-1 , bla-VIM were detected in the majority of samples , but at concentrations orders of magnitude lower . There was high variability across the time series within a plant and between the two plants . We did not find a clear correlation between the AR gene targets with the two human markers , with the exception of a significant positive correlation of bla-VIM and HF183 in the WWTP with a short travel time . This suggests that organisms carrying these genes can establish reservoirs within the sewer systems and be mobilized into the waste stream , potentially adding to the signal detected in WWTP influent . Further , positive correlations of concentration to temperature for bla-KPC and bla-OXA48 further supported fluctuating reservoirs of organisms carrying these genes . Further research is needed on the ecology and distribution of organisms that carry each gene . Next steps include using a combination of culturing and sequencing to understand how free-living organisms within the sewer system may impact results .

Presenter : Melissa Schussman , schussm2 @ uwm . edu

Wastewater Surveillance for SARS-CoV-2 Prevalence in Wisconsin

O . Long 1 , E . Camarato 1 , S . Shrestha 1 , R . Wied 1 , A . Bruckert 1 , L . Simonson 1 , E . Doolittle 1 , D . Everett 1 , G . Knuth 1 , R . Fahney 1 , P . Mullen 1 , N . Kloczko 2 , K . Janssen 1 , J . Hemming 1 , M . Shafer 1 , Wisconsin State Laboratory of Hygiene 1 , Bureau of Communicable Diseases , Wisconsin Department of Health Services 2

SARS-CoV-2 , the causative agent of COVID-19 , is shed into wastewater by infected individuals . The pathogen ’ s presence in sewage makes wastewater-based surveillance ( WBS ) a cost-efficient method of quantifying disease prevalence in a community . Unlike traditional surveillance , WBS is not biased by socioeconomic status , health care availability , or care-seeking behavior and it includes both symptomatic and asymptomatic infected individuals in a sewershed . In response to the COVID-19 pandemic , the Wisconsin State Laboratory of Hygiene ( WSLH ), in partnership with UW-Milwaukee ( UWM ) and the Wisconsin Department of Health Services ( DHS ), has conducted wastewater surveillance to assess SARS-CoV-2 prevalence in Wisconsin . Now in its fourth year , the program covers 45 sampling sites representing roughly 50 % of state residents . In addition to SARS-CoV-2 quantification through WBS , circulating variants can be determined through genomic sequencing . We continue to develop WBS monitoring methods for other pathogens , including respiratory viruses , enteric viruses and antibiotic-resistant organisms . In recognition of the quality and comprehensiveness of our program , the CDC recently named Wisconsin one of only four national Centers of Excellence for wastewater surveillance .

Here , we present our current workflow , from sample collection to the submission of digital PCR data to the state and national publicfacing dashboards . Based on comparison to clinical trends , we demonstrate that wastewater SARS-CoV-2 levels reflect community prevalence and can serve as an early warning of COVID-19 surges . This is important because , since the early summer of 2022 , wastewater data has been more comprehensive and reliable than clinical surveillance due to widespread at-home rapid testing reducing the quantity of clinically reported COVID-19 tests . The broad coverage , cost-efficiency and reduction of biases from traditional clinical surveillance have made WBS a crucial tool to guide public health and individual decisions regarding SARS-CoV-2 transmission in Wisconsin .

Presenter : Oliver Long , Oliver . Long @ slh . wisc . edu