Application of two nucleic acid detection methods in evaluation of thermostable direct hemolysin (TDH) and thermolabilehemolysin (TLH) of Vibrio parahaemolyticus

Objective To compare the sensitivity and specificity of CPA-nucleic acid test strip and real-time PCR for the detection of tlh specific genes and tdh virulence genes of Vibrio parahaemolyticus. Methods The tlh and tdh genes of 655 strains of V.parahaemolyticus were detected by using CPA-nucleic acid test strip and real-time PCR simultaneously. Results The results CPA-nucleic acid test strip and real-time PCR were consistent, the detection rates of tlh gene were all 100% (655/655). The detection results of the tdh gene were consistent too. The detection rates of the tdh gene isolated from clinical patients and seafood were 95.8% (207/216) and 2.27% (10/439) respectively. CPA-nucleic acid test strip had high specificity and sensitivity (6.2103 cfu/ml bacteria liquid) in the detections of tlh and tdh genes, only 1 hour was needed to complete the test after the nucleic acid preparation. Conclusion V.parahaemolyticus strains isolated from clinical patients and seafood generally carry tlh specific gene, but tdh virulence gene mainly exist in clinical specimens. CPA-nucleic acid test strip can be used in the clinical diagnosis of diarrhea caused by V.parahaemolyticus and rapid field detection of food poisoning.