Evaluation of Preservation and Isolation of Stool Pathogens with FecalSwab and WASP

Abstract
The isolation of stool pathogens is difficult due to their fastidious nature and the rapid overgrowth of fecal flora. In this study, we evaluate the preservation and isolation of enteric pathogens from stool using the automated COPAN Walk-Away Specimen Processor (WASP®) in conjunction with FecalSwab® and selenite media. Pathogen viability and fecal commensal abundance was stable in FecalSwab® media under both room-temperature and refrigerated incubation conditions, resulting in a significantly increased number of well-isolated pathogen colonies observed when compared to samples incubated in modified Cary-Blair media.

Isolation of individual pathogen colonies was improved via WASP® planting compared to those planted using the Isoplater system. Furthermore, pre-incubation using the newly formulated COPAN selenite media significantly enhanced the yield of Salmonella enterica serovar Typhimurium. Together, the automated WASP® system, combined with FecalSwab® and selenite media, represents a rapid and efficient approach for the processing of stool specimens compared to standard methods.