Vibrio parahaemolyticus, a Gram-negative, salt-loving bacterium common in marine environments, is the leading cause of acute hepatopancreatic necrosis, also known as “early death syndrome,” in aqua culture, and is responsible for a significant number of foodborne illnesses in humans.
Over the past two decades, the bacteria has led to a significant rise of infections in humans, more so than other foodborne pathogens. These infections primarily result from consuming raw fish and seafood, and particularly, shellfish.
Climate change, causing rising ocean temperatures and ocean acidification, has resulted in increased abundances of Vibrio parahaemolyticus in oceans worldwide. In fact, the most recent FoodNet annual report indicates that the overall incidence in 2021 rose by 45.5% when compared with the annual incidence from 2016 to 2018.
Traditional detection methods for bacteria are labor intensive and time consuming, falling short of the need for accurate, rapid, and convenient detection required by food safety supervision and food enterprises; however, researchers in Shanghai, China, have developed a point-of-care detection method that allows for the quick and sensitive identification of the bacteria in seafood.
This new method uses advanced techniques called recombinant polymerase amplification (RPA) and the CRISPR/Cas12a system, along with a test strip. The method provides a low-cost, simple, and visually clear way to quickly detect Vibrio parahaemolyticus in seafood.
The researchers note that RPA-CRISPR/Cas12a-ICS can detect Vibrio parahaemolyticus in salmon sashimi at extremely low levels, as little as 154 CFU/g, without needing to enrich the sample first. “Our innovative detection platform represents a significant advancement in the rapid and sensitive detection of Vibrio parahaemolyticus, proving especially valuable for ensuring seafood safety and preventing public health crises,” corresponding author Haijuan Zeng, leader of the Biotechnology Research Institute at the Shanghai Academy of Agricultural Sciences, said in a prepared statement.
Zeng, who designed and performed the experiments and analyzed the data, explained that by using this platform, Vibrio parahaemolyticus can be detected in approximately 30 minutes, with a limit of detection of 250 copies/μL for plasmid samples and 140 CFU/mL for bacteria. The platform has been validated with artificially contaminated food samples and various clinical isolates.
Furthermore, in the report, the researchers noted that adjusting the crRNA sequences could enable the identification of various other targets, allowing the optimized ssDNA concentration to be used for detecting different targets. Therefore, the RPA-CRISPR/Cas12a-ICS platform could be employed to detect foodborne pathogens linked to humans, adulterated foods, and even viruses.
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