Establishment of a duplex real-time qPCR method for detection of Salmonella spp. and Serratia fonticola in fishmeal

Abstract

Salmonella spp. is a high-risk bacterial pathogen that is monitored in imported animal-derived feedstuffs. Serratia fonticola is the bacterial species most frequently confused with Salmonella spp. in traditional identification methods based on biochemical characteristics, which are time-consuming and labor-intensive, and thus unsuitable for daily inspection and quarantine work. In this study, we established a duplex real-time qPCR method with invA- and gyrB-specific primers and probes corresponding to Salmonella spp. and S. fonticola. The method could simultaneously detect both pathogens in imported feedstuffs, with a minimum limit of detection for Salmonella spp. and S. fonticola of 197 copies/μL and 145 copies/μL, respectively (correlation coefficient R2 = 0.999 in both cases). The amplification efficiency for Salmonella spp. and S. fonticola was 98.346% and 96.49%, respectively. Detection of fishmeal was consistent with method GB/T 13091-2018, and all seven artificially contaminated imported feed samples were positively identified. Thus, the developed duplex real-time qPCR assay displays high specificity and sensitivity, and can be used for the rapid and accurate detection of genomic DNA from Salmonella spp. and S. fonticola within hours. This represents a significant improvement in the efficiency of detection of both pathogens in imported feedstuffs.

Engineered Gut Symbiotic Bacterium-Mediated RNAi for Effective Control of Anopheles Mosquito Larvae

“…Serratia bacteria are dominant gut symbionts of anopheline mosquitoes and are commonly present in water, soil, and plant surfaces ( 18 , 31 ). S. fonticola , a ubiquitous inhabitant of aquatic environments, soil, and plants ( 32 , 33 ), is a possible source of S. fonticola for field mosquito larvae. Therefore, S. fonticola is an excellent candidate for delivering dsRNA to mosquito larvae in the field.…”

Serratia fonticola and its role as a single pathogen causing emphysematous pyelonephritis in a non-diabetic patient: A case report

“…Since then, S. fonticola has mainly been identified in open wounds (mostly due to trauma) and in the respiratory, gastrointestinal and urinary tracts. Recently, some reports have identified S. fonticola in the biliary tract[ 13 , 18 , 20 ].…”

Recent Developments in Lateral Flow Assays for Salmonella Detection in Food Products: A Review

“…PCR is renowned for its reliability and sensitivity, amplifying nucleic acids to identify Salmonella with precision [36]. Variations such as multiplex PCR [37] and real-time PCR (qPCR) [38] allow for simultaneous detection of multiple pathogens and quantitative analysis, respectively. Despite its efficacy, PCR can be inhibited by certain food components, like fats, which can interfere with the amplification process [39].…”