Development of a rapid diagnostic test based on loop-mediated isothermal amplification to identify the most frequent non-typhoidal Salmonella serovars from culture
In this study, a molecular assay based on loop-mediated isothermal amplification (LAMP) targeting specific gene sequences ofSalmonella Enteritidis,S. Typhimurium,S. Infantis,S. Derby, andS. Choleraesuis has been developed for rapid serovar identification from cultured colonies. A total of 318Salmonella strains and 25 isolates of otherEnterobacterales species that served as negative controls were analyzed. AllS. Enteritidis (n = 40),S. Infantis (n = 27), andS. Choleraesuis (n = 11) strains were correctly identified. Seven out of 104S. Typhimurium and 10 out of 38S. Derby strains missed a positive signal. Cross-reactions of the gene targets were only rarely observed and restricted to theS. Typhimurium primer set (5 false-positives). Sensitivity and specificity of the assay compared to seroagglutination were as follows: 100% and 100% forS. Enteritidis, 93.3% and 97.7% forS. Typhimurium, 100% and 100% forS. Infantis, 73.7% and 100% for S. Derby, and 100% and 100% forS. Choleraesuis, respectively. With results available in just a few minutes of hands-on time and a test run time of 20 min, the LAMP assay developed here may be a useful tool for the rapid identification of commonSalmonella NTS in daily routine diagnostics.