Detection of total and hemolysin-producing Vibrio parahaemolyticus in shellfish using multiplex PCR amplification of tl, tdh and trh

• Published in: Journal of microbiological methods 1999-06, Vol.36 (3), p.215-225
• Main Authors: Bej, Asim K., Patterson, Donald P., Brasher, Cynthia W., Vickery, Michael C.L., Jones, Daniel D., Kaysner, Charles A.
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins; Bacterial Toxins; Bacteriological methods and techniques used in bacteriology; Bacteriology; Biological and medical sciences; DNA Primers; DNA, Bacterial - analysis; Environmental Microbiology; Food Microbiology; Fundamental and applied biological sciences. Psychology; Gene Amplification; Hemolysin; Hemolysin Proteins - biosynthesis; Hemolysin Proteins - genetics; Humans; Microbiology; Microorganism; Mollusca; Multiplex PCR; Ostreidae - microbiology; Polymerase Chain Reaction - methods; Sensitivity and Specificity; Shellfish; Shellfish - microbiology; Vibrio Infections - microbiology; Vibrio parahaemolyticus; Vibrio parahaemolyticus - genetics; Vibrio parahaemolyticus - isolation & purification; Vibrio parahaemolyticus - metabolism; Vibrio parahemolyticus
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/S0167-7012(99)00037-8

Vibrio parahaemolyticus is an important human pathogen which can cause gastroenteritis when consumed in raw or partially-cooked seafood. A multiplex PCR amplification-based detection of total and virulent strains of V. parahaemolyticus was developed by targeting thermolabile hemolysin encoded by tl, thermostable direct hemolysin encoded by tdh, and thermostable direct hemolysin-related trh genes. Following optimization using oligonucleotide primers targeting tl, tdh and trh genes, the multiplex PCR was applied to V. parahaemolyticus from 27 clinical, 43 seafood, 15 environmental, 7 strains obtained from various laboratories and 19 from oyster plants. All 111 V. parahaemolyticus isolates showed PCR amplification of the tl gene; however, only 60 isolates showed amplification of tdh, and 43 isolates showed amplification of the trh gene. Also, 18 strains showed amplification of the tdh gene, but these strains did not show amplification of the trh gene. However, one strain exhibited amplification for the trh but not the tdh gene, suggesting both genes need to be targeted in a PCR amplification reaction to detect all hemolysin-producing strains of this pathogen. The multiplex PCR approach was successfully used to detect various strains of V. parahaemolyticus in seeded oyster tissue homogenate. Sensitivity of detection for all three target gene segments was at least between 10 1–10 2 cfu per 10 g of alkaline peptone water enriched seeded oyster tissue homogenate. This high level of sensitivity of detection of this pathogen within 8 h of pre-enrichment is well within the action level (10 4 cfu per 1 g of shell stock) suggested by the National Seafood Sanitation Program guideline. Compared to conventional microbiological culture methods, this multiplex PCR approach is rapid and reliable for accomplishing a comprehensive detection of V. parahaemolyticus in shellfish.