A multiplex real-time PCR for differential detection and quantification of Salmonella spp., Salmonella enterica serovar Typhimurium and Enteritidis in meats.
Salmonella (S.) Typhimurium and S. Enteritidis are the major causative agents of food-borne illnesses worldwide. Currently, a rapid detection system using multiplex real-time polymerase chain reaction (PCR) has been applied for other food-borne pathogens such as Escherichia coli, Staphylococcus aureus and Streptococcus spp. A multiplex real-time PCR was developed for the simultaneous detection of Salmonella spp., especially S. Typhimurium and S. Enteritidis, in beef and pork. For the specific and sensitive multiplex real-time PCR, three representative primers and probes were designed based on sequence data from Genbank. Among the three DNA extraction methods (boiling, alkaline lysis, and QIAamp DNA Mini Kit), the QIAamp DNA Mini Kit was the most sensitive in this study. The optimized multiplex real-time PCR was applied to artificially inoculated beef or pork. The detection sensitivity of the multiplex real-time PCR was increased. The specificity of the multiplex real-time PCR assay, using 128 pure-cultured bacteria including 110 Salmonella isolates and 18 non-Salmonella isolates, was 100%, 100% and 99.1% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The sensitivity was 100%, 100% and 91.7% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The multiplex real-time PCR assay developed in this study could detect up to 0.54 +/- 0.09 and 0.65 +/- 0.07 log(10) CFU/ml for S. Typhimurium and S. Enteritidis for beef, 1.45 +/- 0.21 and 1.65 +/- 0.07 log(10) CFU/ml for S. Typhimurium and S. Enteritidis for pork, respectively, with all conditions optimized. Our results indicated that the multiplex real-time PCR assay developed in this study could sensitively detect Salmonella spp. and specifically differentiate S. Typhimurium from S. Enteritidis in meats.
Lee
Su Hwa
SH
National Veterinary Research and Quarantine Service, Anyang 430-824, Korea.
Jung
Byeong Yeal
BY
Rayamahji
Nabin
N
Lee
Hee Soo
HS
Jeon
Woo Jin
WJ
Choi
Kang Seuk
KS
Kweon
Chang Hee
CH
Yoo
Han Sang
HS
D000818:Animals; D002417:Cattle; D004269:DNA, Bacterial; D005516:Food Microbiology; D008460:Meat / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D012475:Salmonella / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013552:Swine
D004269:DNA, Bacterial