Lab Matters Fall 2024 | Page 81

APHL 2024 POSTER ABSTRACTS

Analysis of Lead 208 in Retail Juice Samples . J . Chisholm , Young Harris College

We are observing the concentration of Lead 208 in various juice samples . Our study observed concentrations in apple juice , orange juice , grape juice , apple cider and lemonade . These juices are the most common juices that young children tend to consume , which could lead to lead poisoning if not handled or stored properly .

Presenter : John Chisholm , jjchisholm @ yhc . edu

E . coli , Salmonella , Shigella , Vibrio ) appeared to remain unaffected in either submission volume or concordance rate from the change .

Conclusion : Inconsequential changes to the workflow of a single high-volume submitter can have unexpectedly large impacts on an already burdened PHL . With the constant adoption of new and different test methodologies in the clinical setting , a substantial increase in downflow work for PHLs can essentially come without warning carrying heavy costs on resources and time .

Presenter : Raymond Erickson , ray . erickson @ state . mn . us

Analyzing the Impact of CIDT Platform Modifications on Minnesota ’ s Second-largest Clinical Laboratory

R . Erickson , J . Haan , Minnesota Department of Health

Rationale : As the infectious disease detection methods of clinical laboratories change , so does the work for public health laboratories ( PHLs ) in concordance testing — often with substantially fewer resources and labor force . Increases in sample volume have been witnessed nearly every year since the widespread adoption of culture-independent diagnostic testing ( CIDTs ) in Minnesota . However , for large volume submitters , even the change of which CIDT platform is used can have an outsized effect on submission volume and consequently the capacity of PHLs to keep pace . Analyzed here are the effects of one submitter ( Submitter A ), the second largest in volume to the PHL in Minnesota , changing their CIDT platform .

Methods : The study used retrospective data , a year-over-year comparison , to analyze the sample volume of bacterial samples detected on gastrointestinal ( GI ) panels of common CIDT arrays for Submitter A versus overall submission volumes . Submitter A changed their CIDT method from Verigene to BioFire in July 2023 . Additionally , we performed the cost analysis to estimate the impacts these changes can have on both labor hours from sample receiving to testing and their associated cost to PHLs .

Results : Although Campylobacter is detected on both BioFire and Verigene , there was also an increase in the proportion of Campylobacter submissions from submitter A . In the 12 months before the change submitter A averaged 13.2 % of our submissions and 18.5 % in the five months following . This represents around 91 additional samples annually , or a 5.2 % increase in Campylobacter volume overall . This would result in an estimated $ 14,500 in additional culture , confirmation and sequencing costs before labor and amortizing instrumentation .

The largest single factor increase however , was observed in non- Shiga toxin pathogenic E . coli including Enterotoxigenic E . coli ( ETEC ), Enteroaggerative E . coli ( EAEC ) and Enteropathogenic E . coli ( EPEC ), which are listed in Minnesota ’ s Disease Reportable rule . In the 13 months before the change in CIDT ( which previously did not detect these pathogens ), submitter A averaged 2.02 % (± 0.8 ) of the total sample volume submissions for these reportable pathogens . In the first three full months following the change , this submitter increased to 30.5 % (± 2.0 ) of submissions . This resulted in ~ 702.4 additional samples for testing in five months , or a projected 986 annually . This 27.9 % increase in overall volume would result in an estimated $ 27,200 increase in associated costs given culturing , molecular confirmation testing and sequencing of additional Escherichia samples before even calculating labor and amortizing instrumentation . Other common GI pathogenic bacteria ( Shiga Toxin

Discrimination of Viral Capsid Integrity Using a Novel Viability PCR Approach

N . Feirer 1 , W . Randazzo 2 , E . Cuevas-Ferrando 2 , R . Pintó Solé 3 , S . Guiz Arnau 3 , S . Paladugu 4 , T . Kirkland 1 , M . Scurria 4 , J . Cali 1 , G . Sanchez 2 , A . Bosch 3 , S . Mondal 1 , Promega Corporation 1 , Institute of Agrochemistry and Food Technology 2 , Enteric Virus Laboratory , University of Barcelona 3 , Promega Biosciences LLC 4

Norovirus and hepatitis infections are two of the leading causes of viral food-borne illnesses in both adults and children worldwide . As a result , consistent and rapid quantitative methods for the discrimination of infectious viruses in food or water samples are needed . Current culture-based methods for viral detection have long been considered the gold standard for infectivity assessment , but these approaches suffer from lengthy incubation periods , low sensitivity , or in the case of norovirus , lack a suitable culture-based system altogether . RT-qPCR based viral detection directly addresses these issues and is quickly becoming a widely adopted method for rapid detection of pathogenic viruses .

The main drawback of existing PCR approaches is the inability during analysis of test results to determine the proportion of viruses in a sample are still infectious . This presents a substantial challenge in epidemiologic investigations , in which viral RNA from degraded , denatured , or lysed viruses is still amplified and presents as a false-positive result . In this study we show that by using a cellimpermeable intercalating molecule ( Viability PCR Reagent ) that exclusively binds to and covalently modifies RNA from compromised virus particles we can discriminate between intact and non-intact virus capsids using standardized RT-qPCR detection technology .

We first demonstrate that our Viability Reagent is able to eliminate RT-qPCR signal from naked norovirus and hepatitis A virus ( HAV ) genomes , ensuring the feasibility of utilizing Viability PCR with RNA viruses . Subsequently , we show that treatment with increasing concentrations of Viability PCR Reagent is inversely proportional with a reduction of RT-qPCR signal from thermally inactivated Norovirus and HAV . This reduction is concordant with an observed reduction in titer from traditional culture-based infectivity assays . RT-qPCR amplification signal from intact viruses was not affected by the Viability PCR Reagent , even by the highest treatment concentrations . In addition , we present data that the Viability PCR workflow is feasible in complex matrices , as RT-qPCR signal from pressure-inactivated Norovirus residing in strawberry puree is significantly reduced . Lastly , we demonstrate the applicability of this technique beyond enteric viruses , as RT-qPCR signal from thermallyinactivated SARS-CoV-2 is reduced following treatment with Viability PCR Reagent .

These analyses are pivotal in understanding the challenges faced by public health laboratories in the timely and accurate identification