Detection of Salmonella species in faeces by latex agglutination in enrichment broth.

A test was developed for the detection of Salmonella spp. in stool enrichment broths using latex particles coated with polyvalent salmonella H antiserum. The test detected salmonella in 146 of 168 positive specimens and gave a positive result in two of 308 culture negative specimens. There was a positive predictive value of 99.6% and a negative predictive value of 95.4%, with an overall efficiency of 95%. Results were available within 18h of receipt compared to the 48-72h required for conventional methods. A positive result was also available within 4h for 17 of 18 specimens tested from patients with active salmonella gastroenteritis. The latex test was rapid, easy to perform and cost-effective, and would appear to be a useful aid in the rapid diagnosis of salmonella infection and carriage.