Incidence, virulence genes and antimicrobial resistance of Vibrio parahaemolyticus isolated from seafood

The objective of the study was to establish the incidence, pathogenic factors and antimicrobial resistance of Vibrio parahaemolyticus in seafood from retail shops in Bulgaria. A hundred and eighty samples of sea fish, mussels, oysters, veined rapa whelks, shrimps and squids were included in the study. PCR methods were used to identify V. parahaemolyticus and prove tdh and trh genes. Antimicrobial resistance was established by disc diffusion method, and MAR index was calculated. The results proved the presence of V. parahaemolyticus in 24% (44/180) of the seafood samples. tdh-positive V. parahaemolyticus was not found, while the trh gene was detected in one veined rapa whelk isolate. All isolates were susceptible to Sulfamethoxazole/trimethoprim, Tetracycline, Gentamycin, Amoxicillin-clavulanic acid, Amikacin, Ciprofloxacin, and Levofloxacin. Intermediate resistance was found to Ampicillin (25%; 11/44), Cefepime (16%; 7/44), and Ceftazidime (2%; 1/44). The results showed that 16% (7/44) of the isolates were resistant to Cefepime, 9% (4/44) to Ampicillin, and 5% (2/44) to Cefta-zidime. MAR-index values ranged from 0.10 to 0.30. The incidence of pathogenic and multidrug-resistant V. parahaemolyticus strains in seafood offered on the market poses a risk to consumer health.

Automated summary

The study aimed to investigate the occurrence, pathogenic factors, and antimicrobial resistance of Vibrio parahaemolyticus in seafood sold in Bulgarian retail shops. A total of 180 seafood samples including sea fish, mussels, oysters, veined rapa whelks, shrimps, and squids were analyzed. PCR methods were used to identify V. parahaemolyticus and detect tdh and trh genes. The results showed that 24% of the samples were positive for V. parahaemolyticus, with no tdh-positive strains found and only one veined rapa whelk isolate carrying the trh gene. Antimicrobial susceptibility testing revealed susceptibility to most antibiotics, with intermediate resistance observed for a few. The study highlights the presence of pathogenic and multidrug-resistant V. parahaemolyticus strains in seafood, posing a risk to consumer health.