REAL-TIME PCR METHOD FOR DETECTION OF SALMONELLA SPP. IN ENVIRONMENTAL SAMPLES
38th Annual congress on Microbes Infection
September 28-29, 2017 | London, UK
Kuppuswamy N Kasturi and Tomas Drgon
US Food and Drug Administration, New York, USA
US Food and Drug Administration, Maryland, USA
Posters & Accepted Abstracts : Microbiology: Current Research
The methods currently used in FDA (Food and Drug Administration) field laboratories and other public health laboratories for detecting Salmonella in food/environmental samples require 2 days and have limited sensitivity. We describe the development and validation of a real-time PCR method that detected Salmonella and presence of group D in 24 h. Primers and probes specific to the invA gene of Salmonella, group D, and Enteritidis serovar were designed and evaluated for the inclusivity and exclusivity using a panel of 329 Salmonella isolates consisting 126 serovars from 32- O groups and 22 non-Salmonella environmental organisms. The invA-, group D- and Enteritidis-specific sets identified the isolates accurately. The PCR method was100% inclusive for Salmonella spp. and had a detection limit of 2 copies of Salmonella DNA per reaction. A Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the Vitek immunodiagnostic assay system method (VIDAS) method that is currently used. The method is more specific and did not report any false-negatives. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples.