Antibiotic resistance pattern and its correlation to the presence of tdh gene and CRISPR-Cas system in Vibrio parahaemolyticus strains isolated from seafood

Abstract

Vibrio parahaemolyticus is a pathogen native to the aquatic environment. In this study, 46 environmental V. parahaemolyticus isolates were subjected to a correlational analysis to find the association between their antimicrobial susceptibility pattern, prevalence of CRISPR-Cas system and thermostable direct hemolysin (tdh) gene. Antibiotic resistance profiling against eleven antibiotics revealed the isolates to be multidrug resistant. Isolates exhibited highest resistance to vancomycin (97.8%) followed by ampicillin (91.3%), cefotaxime (69.6%), ceftazidime/clavulanic acid (54.4%), ceftazidime (45.7%) and gentamicin (39.1%). CRISPR loci and tdh gene were detected in 47.83 and 58.7% of strains respectively. No significant correlation was observed between antibiotic resistance to presence of CRISPR, except in the case of gentamicin wherein, a negative correlation was seen (r=-0.272, p<0.10). Similarly, tdh did not correlate to antibiotic resistance. Seventeen strains in this study harboured the CRISPR loci as well as tdh gene, the association of which was found to be statistically significant.

Characterization and Analysis of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) in Pandemic and Non-Pandemic Vibrio parahaemolyticus Isolates from Seafood Sources

“…The result of this study corroborates earlier findings; however, we could detect CRISPR in two of the tdh− trh + and one of the tdh− trh− isolates. The presence of CRISPR in the tdh− isolates were also reported in a previous study [41]. The CRISPR loci detected in this study is located on the V. parahaemolyticus island-7 (VPAI-7) region of chromosome 2, which encodes the tdh gene and are closely associated with tdh+ V. parahaemolyticus [43][44][45], thus this may be the reason why this CRISPR loci is more prevalent in the tdh+ isolates.…”

“…In this study, nearly half of the V. parahaemolyticus isolates had an MAR index ≥ 0.2, which indicated that these isolates originated from high-risk sources that have been exposed to antibiotics, such as humans and aquaculture, and seafood might be considered as a possible vehicle for pathogen transmission. Previous studies have reported that the V. parahaemolyticus isolates from seafood showed an MAR index > 0.2 [41,42]. Thus, antimicrobial resistance should continue to be monitored to ensure seafood safety.…”

Serological and Antibiotic Resistance Patterns As Well As Molecular Characterization of Vibrio parahaemolyticus Isolated from Coastal Waters in the Eastern Province of Saudi Arabia

“…This agrees with other studies elsewhere that detected an MAR index above 0.2 among 45% of pandemic and non-pandemic V. parahaemolyticus isolated from seafood [69]. The MAR indices that exceed 0.2 indicated that these isolates originated from high-risk contamination and may pose human risks [70,71].…”