Antimicrobial Drug-resistance Profile of Vibrio Parahaemolyticus isolated from Japanese Horse Mackerel (Trachurus Japonicus)

Antimicrobial susceptibility profile and molecular characterization of Vibrio parahaemolyticus strains isolated from imported shrimps

Vibrio parahaemolyticus is a threat to human health and one of the leading bacterial causes of seafood-borne infection worldwide. This pathogen is autochtonous in the marine environment and is able to acquire antimicrobial resistance (AMR) mechanisms, which is a global concern. However, the emergence of AMR V. parahaemolyticus strains in seafood is still understudied, as interpretation criteria for this species for antimicrobial susceptibility tests are limited in the literature. In this study, we investigated the susceptibility profiles to clinically important antibiotics and the associated genetic determinants of V. parahaemolyticus isolates cultured from imported shrimps. Based on the analysis of the resistance phenotypes of 304 V. parahaemolyticus isolates, we have defined experimental epidemiological cutoff values (COWT) for 14/15 antibiotics tested. We observed that 19.1% of the bacterial isolates had acquired resistance to at least one antibiotic class. The highest number of resistance was associated with tetracycline (14.5% of the strains) and trimethoprim-sulfamethoxazole (3.6%). Moreover, seven strains were multidrug-resistant (MDR, resistant to at least three antibiotic classes). The most frequently identified genes in these strains were aph(3″)-Ib/aph(6)-Id (aminoglycoside resistance), sul2 (sulfonamide), tet(59) (tetracycline), and floR (chloramphenicol). The SXT/R391 family ICE and class 1 integron-integrase genes were detected by PCR in three and one MDR V. parahaemolyticus strains, respectively. Consequently, V. parahaemolyticus in seafood can act as a reservoir of AMR, constituting a health risk for the consumer.IMPORTANCEOur study on "Antimicrobial Resistance Profiles and Genetic Determinants of Vibrio parahaemolyticus Isolates from Imported Shrimps" addresses a critical gap in understanding the emergence of antimicrobial resistance (AMR) in this seafood-associated pathogen. Vibrio parahaemolyticus is a major cause of global seafood-borne infections, and our research reveals that 19.1% of isolates from imported shrimps display resistance to at least one antibiotic class, with multidrug resistance observed in seven strains. Importantly, we establish experimental epidemiological cutoff values for antibiotic susceptibility, providing valuable criteria specific to V. parahaemolyticus. Our findings underscore the potential risk to consumers, emphasizing the need for vigilant monitoring and intervention strategies. This study significantly contributes to the comprehension of AMR dynamics in V. parahaemolyticus, offering crucial insights for global public health. The dissemination of our research through Microbiology Spectrum ensures broad accessibility and impact within the scientific community and beyond.

Incidence, genetic diversity, and antimicrobial resistance profiles of Vibrio parahaemolyticus in seafood in Bangkok and eastern Thailand

Background

Emergence of Vibrio parahaemolyticus pandemic strain O3:K6 was first documented in 1996. Since then it has been accounted for large outbreaks of diarrhea globally. In Thailand, prior studies on pandemic and non-pandemic V. parahaemolyticus had mostly been done in the south. The incidence and molecular characterization of pandemic and non-pandemic strains in other parts of Thailand have not been fully characterized. This study examined the incidence of V. parahaemolyticus in seafood samples purchased in Bangkok and collected in eastern Thailand and characterized V. parahaemolyticus isolates. Potential virulence genes, VPaI-7, T3SS2, and biofilm were examined. Antimicrobial resistance (AMR) profiles and AMR genes (ARGs) were determined.

Methods

V. parahaemolyticus was isolated from 190 marketed and farmed seafood samples by a culture method and confirmed by polymerase chain reaction (PCR). The incidence of pandemic and non-pandemic V. parahaemolyticus and VPaI-7, T3SS2, and biofilm genes was examined by PCR. AMR profiles were verified by a broth microdilution technique. The presence of ARGs was verified by genome analysis. V. parahaemolyticus characterization was done by multilocus sequence typing (MLST). A phylogenomic tree was built from nucleotide sequences by UBCG2.0 and RAxML softwares.

Results

All 50 V. parahaemolyticus isolates including 21 pathogenic and 29 non-pathogenic strains from 190 samples had the toxRS/old sequence, indicating non-pandemic strains. All isolates had biofilm genes (VP0950, VP0952, and VP0962). None carried T3SS2 genes (VP1346 and VP1367), while VPaI-7 gene (VP1321) was seen in two isolates. Antimicrobial susceptibility profiles obtained from 36 V. parahaemolyticus isolates revealed high frequency of resistance to colistin (100%, 36/36) and ampicillin (83%, 30/36), but susceptibility to amoxicillin/clavulanic acid and piperacillin/tazobactam (100%, 36/36). Multidrug resistance (MDR) was seen in 11 isolates (31%, 11/36). Genome analysis revealed ARGs including blaCARB (100%, 36/36), tet(34) (83%, 30/36), tet(35) (42%, 15/36), qnrC (6%, 2/36), dfrA6 (3%, 1/36), and blaCTX-M-55 (3%, 1/36). Phylogenomic and MLST analyses classified 36 V. parahaemolyticus isolates into 5 clades, with 12 known and 13 novel sequence types (STs), suggesting high genetic variation among the isolates.

Conclusions

Although none V. parahaemolyticus strains isolated from seafood samples purchased in Bangkok and collected in eastern Thailand were pandemic strains, around one third of isolates were MDR V. parahaemolyticus strains. The presence of resistance genes of the first-line antibiotics for V. parahaemolyticus infection raises a major concern for clinical treatment outcome since these resistance genes could be highly expressed under suitable circumstances.

On-Farm Practices Associated with Multi-Drug-Resistant Escherichia coli and Vibrio parahaemolyticus Derived from Cultured Fish

Aquaculture activities have been implicated as responsible for the emergence of antimicrobial resistance (AMR), leading to broad dissemination and transference of antibiotic resistance to pathogens that affect humans and animals. The current study investigates the on-farm practices and environmental risk factors that can potentially drive the development and emergence of multi-drug-resistant (MDR) Escherichia coli and Vibrio parahaemolyticus in the aquaculture system. A cross-sectional study was conducted on 19 red hybrid tilapia (Oreochromis spp.) and 13 Asian seabass (Lates calcarifer, Bloch 1970) farms on the west coast of peninsular Malaysia. Data were collected using a structured questionnaire pertaining to farm demography, on-farm management practices and environmental characteristics. Multi-drug-resistant E. coli (n = 249) and V. parahaemolyticus (n = 162) isolates were analyzed using multi-level binary logistic regression to identify important drivers for the occurrence and proliferation of the MDR bacteria. On-farm practices such as manuring the pond (OR = 4.5; 95% CI = 1.21–16.57) were significantly associated with the occurrence of MDR E. coli, while earthen ponds (OR = 8.2; 95% CI = 1.47–45.2) and human activity adjacent to the farm (OR = 4.6; 95% CI = 0.75–27.98) were associated with an increased likelihood of MDR V. parahaemolyticus. Considering the paucity of information on the drivers of AMR in the aquaculture production in this region, these findings indicate the targeted interventions implementable at aquaculture farms to efficiently abate the risk of MDR amongst bacteria that affect fish that are of public health importance.