Influence of enrichment media and application of a PCR based method to detect Salmonella in poultry industry products and clinical samples

To attempt the rapid detection of Salmonella enterica, we have coupled a cu lture procedure with PCR amplification of the genus-specific invElinvA gene s. The method was applied to different kinds of samples from the poultry in dustry and evaluated by using hydrolyzed feather meal, meat meal, litter an d viscera, all experimentally inoculated with a known number of Salmonella followed by cultivation in selenite-cystine broth prior to the PCR reaction . The expected 457 bp specific DNA fragment could be amplified from dilutio ns containing as few as 5.7 CFU, indicating that the PCR technique can be s uccessfully coupled with culture in an enrichment broth to distinguish Salm onella species from other enteric bacteria present in samples from the poul try industry. Tetrathionate broth proved to be a much better enrichment med ia compared to selenite-cystine when the presence of Salmonella was evaluat ed by PCR in 1-day-old chicks experimentally infected with known numbers of Salmonella. Samples included cecal tonsils and viscera, collected at 48 h and 7 days postinfection. The PCR technique was more sensitive in detecting infected animals than the standard microbiological procedure, which detect ed only 47% of all PCR positive samples. (C) 2001 Elsevier Science B.V. All rights reserved.