B-230 Analytical performance of a new investigational use only (IUO) Panther Fusion® Gastrointestinal (GI) Expanded Bacterial Assay

Background Acute diarrhea from gastrointestinal (GI) infections is a leading cause of hospitalization and outpatient visits globally, with an estimated 500 million cases and 230,000 deaths annually. Accurate pathogen identification is crucial for effective treatment. Bacterial, viral, and parasitic GI infections often present similar symptoms, necessitating laboratory testing for proper diagnosis. The IUO Panther Fusion® GI Expanded Bacterial Assay is a multiplex real-time PCR test for the rapid detection of Yersinia enterocolitica, Vibrio species (V. parahaemolyticus, V. vulnificus, V. cholerae), Shigatoxigenic Escherichia coli (STEC) O157, and Plesiomonas shigelloides. This study evaluated the analytical performance of the GI Expanded Bacterial Assay on the Panther Fusion® system. Methods Stool specimens collected in Cary-Blair (CB) and spiked with non-target and/or assay targets were transferred to the Aptima® Multitest collection tubes (Hologic), then loaded on the Panther Fusion system for nucleic acid isolation, amplification, and detection. The limit of detection (LoD), inclusivity and specificity of the Panther Fusion® GI Expanded Bacterial Assay were evaluated. Results Limit of Detection (LoD): LoD values for each bacterial target are summarized in Attachment 1. Inclusivity 64 clinically relevant inclusivity strains for assay targets were tested at 3x LoD in stool matrix. All tested strains demonstrated 100% reactivity. Specificity 108 non-target organisms, including bacteria, virus, parasite and yeast were tested in the absence and in the presence of assay targets. In the absence of assay targets, results were negative except for Vibrio alginolyticus, where cross reactivity was observed when tested at concentrations above 1e4 CFU/mL. All intended targets at 3xLoD tested in the presence of unintended organisms were 100% positive. Interfering Substances 40 substances of endogenous and exogenous origin were evaluated for interference with and without assay targets. All panels gave valid results. All negative panels were 100% negative, and all positive panels were 100% positive on testing in the presence of potential interfering substances. Conclusion Panther Fusion® GI Expanded Bacterial Assay demonstrated excellent analytical performance in detection and differentiation of intended targets. This assay will provide a sensitive, accurate and rapid molecular tool for automated syndromic investigation of pathogenic bacteria in human stool.