New medium detects enteric pathogens by color change

June 27, 2013

Hardy Diagnostics, an ISO-certified biomedical firm, has announced the release of HardyCHROM SS, a highly selective chromogenic medium recommended for use as a primary screening medium for the isolation and differentiation of both Salmonella and Shigella spp from stool cultures.

According to company representatives, with this new medium, Salmonella and Shigella can easily be distinguished from non-pathogenic enteric bacteria based on colony color. HardyCHROM SS simultaneously detects both Salmonella and Shigella spp. while ruling out non-pathogenic enteric bacteria (both lactose and non-lactose-fermenting organisms). Most Proteus spp. do not produce black colonies (H2S) and do not produce a color change on this medium and therefore cannot be confused with Salmonella and Shigella.

Hardy is publicizing a recent scientific study performed by the University of Washington School of Medicine in Seattle. The study concluded that HardyCHROM SS Agar, combined with MALDI-TOF-MS, improved the turnaround time for the reporting of negative results by up to two days, while reducing the costs associated with stool cultures by almost 50%. In addition, HardyCHROM SS Agar successfully recovered all Salmonella and Shigella isolates tested and yielded the expected color reactions in all cases. HardyCHROM SS Agar demonstrated improved sensitivity and specificity over MacConkey and HE Agars. The study was presented as a poster at the 2013 American Society for Microbiology (ASM) conference held in Denver, CO, last month. View the poster.