Prevalence of Vibrio parahaemolyticus in seafood and water environment in the Mekong Delta, Vietnam

Global and regional final point-of-drinking water prevalence of Vibrio pathogens: a systematic analysis with socioeconomic, global health security, and WASH indices-guided meta-regressions

The final point-of-drinking water (FPODW) exposure to Vibrio and waterborne pathogens remains a misaim surveillance target. Therefore, the current study purposed to estimate the global and regional prevalence of Vibrio pathogens in FPODW. Vibrio-FPODW data derived from integrated databases per PRISMA protocol were fitted to a random-intercept-logistic mixed-effects and meta-regression models. The global FPODW Vibrio prevalence was 5.13% (95%CI: 2.24-11.30) with 7.76% (6.84-8.78) cross-validated value. Vibrio prevalence in different FPODW varied with the highest in unclassified (13.98%, 3.98-38.95), household stored (6.42%, 1.16-28.69), municipal (4.39%, 1.54-11.90), and bottled (1.06%, 0.00-98.57) FPODW. Regionally, FPODW Vibrio prevalence varied significantly with highest in Africa (6.31%, 0.49-47.88), then Asia (4.83%, 2.01-11.18). Similarly, it varied significantly among income classification with the highest from low-income (8.77%, 0.91-50.05), then lower-middle-income (6.16%, 2.75-13.20), upper-middle-income (0.23%, 0.00-82.04), and 0.94% (0.19-2.72) in high-income economies. Among the WHO region, it varied significantly from 1.41% (0.17-10.45) in Eastern Mediterranean, 6.31% (0.49-47.88) in Africa to 8.86% (3.85-19.06) in South-East Asia and declining among SDI-quintiles from 11.64% (3.29-33.83) in Low-SDI, 10.59% (4.58-22.61) in High-middle-SDI to 0.26% (0.01-9.09) in Middle-SDI. FPODW Vibrio prevalence was 7.31% (2.94-17.03) in the low-GHSIG, followed by 4.55% (0.00-100.00) in the upper-GHSIG, and 2.21% (0.31-14.24) in middle-GHSIG; rural (4.18%, 0.06-76.17) and urban (5.28%, 2.35-11.44) settings. Also, sample size, SDI, SDI-quintiles, and nation significantly explained 14.12%, 10.91%, 30.35%, and 87.65% variance in FPODW Vibrio prevalence, respectively as a univariate influence. Additionally, 11.90% variance in FPODW Vibrio prevalence explained mortality rate attributed to unsafe WASH services. In conclusion, the study revealed a substantial high FPODW prevalence of Vibrio calling for initiative-taking and intentional surveillances of waterborne pathogens at the neglected stage across nations in order to achieve sustainably the SDG 3.

Antimicrobial susceptibility and genomic characterization of Vibrio parahaemolyticus isolated from aquatic foods in 15 provinces, China, 2020

Prevalent in marine, estuarine and coastal environments, Vibrio parahaemolyticus is one of the major foodborne pathogens which can cause acute gastroenteritis through consumption of contaminated food. This study encompassed antimicrobial resistance, molecular characteristics and phylogenetic relationships of 163 V. parahaemolyticus isolated from aquatic foods across 15 provinces in China. The isolates showed high resistance rates against ampicillin (90.80 %, 148/163) and cefazolin (72.39 %, 118/163). Only 5 isolates demonstrated multi-drug resistance (MDR) phenotypes. A total of 37 different antibiotic resistance genes (ARGs) in correlation with seven antimicrobial categories were identified. tet(34) and tet(35) were present in all 163 isolates. Other most prevalent ARGs were those conferring resistance to β-lactams, with prevalence rate around 18.40 % (30/163). The virulence genes tdh and trh were found in 17 (10.43 %) and 9 (5.52 %) isolates, respectively. Totally 121 sequence types (STs) were identified through whole genome analysis, among which 60 were novel. The most prevalent sequence type was ST3 (9.20 %, 15/163), which shared the same genotype profile of trh_, tdh+ and blaCARB-22+. Most of the tdh+V. parahaemolyticus isolates was clustered into a distinctive clade by the phylogenetic analysis. Our study showed that the antimicrobial resistance of V. parahaemolyticus in aquatic foods in China was moderate. However, the emerging of MDR isolates implicate strengthened monitoring is needed for the better treatment of human V. parahaemolyticus infections. High genetic diversity and virulence potential of the isolates analyzed in this study help better understanding and evaluating the risk of V. parahaemolyticus posed to public health.

Prevalence, multidrug resistance, and biofilm formation of Vibrio parahaemolyticus isolated from fish mariculture environments in Cat Ba Island, Vietnam

BACKGROUND

Vibrio parahaemolyticus is a major foodborne pathogen in aquatic animals and a threat to human health worldwide. This study investigated the prevalence, antimicrobial resistance, antimicrobial resistance genes (ARGs), and biofilm formation of V. parahaemolyticus strains isolated from fish mariculture environments in Cat Ba Island, Vietnam.

METHODS

In total, 150 rearing water samples were collected from 10 fish mariculture farms in winter and summer. A polymerase chain reaction assay was used to identify V. parahaemolyticus, its virulence factors, and ARGs. The antimicrobial resistance patterns and biofilm formation ability of V. parahaemolyticus strains were investigated using the disk diffusion test and a microtiter plate-based crystal violet method, respectively.

RESULTS

Thirty-seven V. parahaemolyticus isolates were recovered from 150 samples. The frequencies of the tdh and trh genes among V. parahaemolyticus isolates were 8.1% and 21.6%, respectively. More than 90% of isolates were susceptible to ceftazidime, cefotaxime, and chloramphenicol, but over 72% were resistant to ampicillin, tetracycline, and erythromycin. Furthermore, 67.57% of isolates exhibited multidrug resistance. The presence of ARGs related to gentamicin (aac(3)-IV), tetracycline (tetA) and ciprofloxacin (qnrA) in V. parahaemolyticus isolates was identified. Conversely, no ARGs related to ampicillin or erythromycin resistance were detected. Biofilm formation capacity was detected in significantly more multidrug-resistant isolates (64.9%) than non-multidrug-resistant isolates (18.9%).

CONCLUSION

Mariculture environments are a potential source of antibiotic-resistant V. parahaemolyticus and a hotspot for virulence genes and ARGs diffusing to aquatic environments. Thus, the prevention of antibiotic-resistant foodborne vibriosis in aquatic animals and humans requires continuous monitoring.

Polychaeta-mediated synthesis of gold nanoparticles: A potential antibacterial agent against Acute Hepatopancreatic Necrosis Disease (AHPND)-causing bacteria, Vibrio parahaemolyticus

Gold nanoparticles (AuNPs) have emerged as a promising application in aquaculture. Their nano-sized dimensions, comparable to pathogens offer potential solutions for combating antibiotic resistance. In this study, AuNPs were synthesized by using polychaetes, Marphysa moribidii as the bio-reducing agent. Modifications were made to reduce agglomeration in green-synthesized AuNPs through ultrasonication. The antibacterial activities of AuNPs against V. parahaemolyticus were evaluated. The physicochemical characteristics of the green synthesized AuNPs were comprehensively investigated. The successful formation of AuNPs was confirmed by the appearance of a red ruby colour and the presence of surface Plasmon resonance (SPR) absorption peaks at 530 nm as observed from UV-vis spectroscopy. Scanning electron microscopy (SEM) revealed spherical-shaped AuNPs with some agglomerations. Transmission electron microscopy (TEM) showed particle size of AuNPs ranging from 10 nm to 60 nm, meanwhile dynamic light scattering (DLS) analysis indicated an average particle size of 24.36 nm. X-ray diffraction (XRD) analysis confirmed the high crystallinity of AuNPs, and no AuNPs were detected in the polychaetes extracts prior to synthesis. A brief ultrasonication significantly reduced the tendencies for AuNPs to coalesce. The green-synthesized AuNPs demonstrated a remarkable antibacterial efficacy against V. parahaemolyticus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests revealed that a concentration of 0.3 g/ml of AuNPs effectively inhibited V. parahaemolyticus. These findings highlighted the potential of green-synthesized AuNPs as antibacterial agents for the prevention and management of AHPND in aquaculture.

Comparative genomic analysis reveals the potential transmission of Vibrio parahaemolyticus from freshwater food to humans

Vibrio parahaemolyticus is an increasingly important foodborne pathogen that cause acute gastroenteritis in humans. However, the prevalence and transmission of this pathogen in freshwater food remains unclear. This study aimed to determine the molecular characteristics and genetic relatedness of V. parahaemolyticus isolates obtained from freshwater food, seafood, environmental, and clinical samples. A total of 138 (46.6%) isolates were detected from 296 food and environmental samples, and 68 clinical isolates from patients. Notably, V. parahaemolyticus was more prevalent in freshwater food (56.7%, 85/150) than in seafood (38.8%, 49/137). Virulence phenotype analyses revealed that the high motility of isolates from freshwater food (40.0%) and clinical isolates (42.0%) was higher than that of isolates from seafood (12.2%), whereas the biofilm-forming capacity of freshwater food isolates (9.4%) was lower than that of seafood (22.4%) and clinical isolates (15.9%). Virulence genes analysis showed that 46.4% of the clinical isolates contained the tdh gene encoding thermostable direct hemolysin (TDH) and only two freshwater food isolates contained the trh gene encoding TDH-related hemolysin (TRH). Multilocus sequence typing (MLST) analysis divided the 206 isolates into 105 sequence types (STs), including 56 (53.3%) novel STs. ST2583, ST469, and ST453 have been isolated from freshwater food and clinical samples. Whole-genome sequence (WGS) analyses revealed that the 206 isolates were divided into five clusters. Cluster II contained isolates from freshwater food and clinical samples, whereas the other clusters contained isolates from seafood, freshwater food, and clinical samples. In addition, we observed that ST2516 had the same virulence pattern, with a close phylogenetic relationship to ST3. The increased prevalence and adaption of V. parahaemolyticus in freshwater food is a potential cause of clinical cases closely related to the consumption of V. parahaemolyticus contaminated freshwater food.

Multiplex PCR-Lateral Flow Dipstick Method for Detection of Thermostable Direct Hemolysin (TDH) Producing V. parahaemolyticus

Vibrio parahaemolyticus is usually found in seafood and causes acute gastroenteritis in humans. Therefore, a detection method of pathogenic V. parahaemolyticus is necessary. Multiplex PCR combined with lateral flow dipstick (LFD) assay was developed to detect pathogenic V. parahaemolyticus. Biotin-, FAM-, and Dig-conjugated primers targeting thermolabile hemolysin (TLH) and thermostable direct hemolysin (TDH) genes were used for multiplex PCR amplification. The condition of the method was optimized and evaluated by agarose gel electrophoresis and universal lateral flow dipstick. The specificity assay was evaluated using strains belonging to seven foodborne pathogen species. The sensitivity of the method was also evaluated using DNA in the concentration range of 0.39-100 ng/reaction. The artificial spiking experiment was performed using 10 g of shrimp samples with an enrichment time of 0, 4, and 8 h with 10¹, 10², and 10³ CFU of V. parahaemolyticus. The developed multiplex PCR-LFD assay showed no non-specific amplification with a limit of the detection of 0.78 ng DNA/reaction visualized by agarose gel electrophoresis and 0.39 ng DNA with LFD assay. The artificial spiking experiment demonstrated that this method could detect pathogenic V. parahaemolyticus at 10 CFU/10 g shrimp samples following a 4 h of enrichment. Multiplex PCR-LFD assay was therefore established for detecting pathogenic V. parahaemolyticus with high sensitivity and specificity and might be a useful tool to develop a detection kit used in the food safety sector.

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 Ceftazidime. 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.

Evaluation of the pathogenesis of non-typical strain with α-hemolysin, Vibrio parahaemolyticus 353, isolated from Chinese seafood through comparative genome and transcriptome analysis

Vibrio parahaemolyticus outbreaks frequently occur, causing gastrointestinal sickness owing to the consumption of aquatic foods by various virulence factors; however, the mechanism of pathogenesis is still unknown. In this study, a non-typical strain of V. parahaemolyticus, named VP353, was isolated from shrimp in China. Its comparative genome and transcriptome after infection with Caco-2 cells were examined to illustrate the mechanisms of its pathogenesis. VP353 was a tdh-trh- strain but uncommonly manifested robust cytotoxicity towards Caco-2 cells. Compared with the standard strain RIMD2210633, VP353 harbored alpha-hemolysins (hlyA, hlyB, hlyC, and hlyD) was first reported in V. parahaemolyticus and showed high diversity in the T3SS2 gene cluster. Moreover, the expression of flagella, T2SS, quorum sensing-related genes, hlyA, hlyC were up-regulated, and hlyB, hlyD were down-regulated. In summary, our results demonstrate that some novel virulence factors contribute to the pathogenesis of V. parahaemolyticus infection.

Quantification and Antimicrobial Resistance of Vibrio parahaemolyticus in Retail Seafood in Hanoi, Vietnam

ABSTRACT

Vibrio parahaemolyticus is a major cause of foodborne diseases and a significant threat to human health worldwide. Most of the infections caused by V. parahaemolyticus are usually associated with the consumption of raw or undercooked seafood. This study was conducted to determine the prevalence, quantitative load, and antimicrobial resistance of V. parahaemolyticus in retail seafood in Hanoi, Vietnam. A total of 120 seafood samples consisting of marine fish (n = 30), oysters (n = 30), shrimp (n = 30), and squid (n = 30) were purchased from different traditional markets in Hanoi between May and October 2020. Isolation of V. parahaemolyticus was based on ISO/TS 21872-1:2017, and the most-probable-number (MPN) method was used for quantification. The disk diffusion method was applied for antimicrobial susceptibility testing. Overall, V. parahaemolyticus was detected in 58.33% of the samples. V. parahaemolyticus was most commonly isolated in shrimp samples, with a prevalence of 86.67%, followed by fish (53.33%), squid (53.33%), and oysters (40%). One V. parahaemolyticus isolate from an oyster carrying the trh gene was detected. Of the positive samples, 27.14% contained V. parahaemolyticus counts of less than 2 log MPN/g, whereas 44.29% ranged from 2 to 4 log MPN/g and 28.57% contained more than 4 log MPN/g. Regarding antimicrobial resistance, 85.71% of V. parahaemolyticus isolates were resistant to at least one antibiotic tested. The highest rate of resistance was observed against ampicillin (81.43%), followed by cefotaxime (11.43%), ceftazidime (11.43%), trimethoprim-sulfamethoxazole (8.57%), and tetracycline (2.86%). The results demonstrate the high prevalence and quantitative load and the antimicrobial resistance of V. parahaemolyticus isolated from seafood sold in the study area.

HIGHLIGHTS

Occurrence and antibiotic resistance of Vibrio parahaemolyticus isolated from the Tunisian coastal seawater

Vibrio parahaemolyticus is a gram-negative bacterium ubiquitous in seawater or estuarine water throughout the world. It is a major cause of seafood gastroenteritis complications. In this study, the presence of V. parahaemolyticus was investigated in 66 seawater samples collected during 2018 from 15 stations spread along the Tunisian coast using selective media including CHROMagar Vibrio media. The results show that only eight samples contained V. parahaemolyticus. However, while Vibrio alginolyticus was detected in all samples; both Vibrio cholerae and Vibrio vulnificus were not found. Nine of the presumed V. parahaemolyticus colonies were purified on tryptic soy agar from eight positive samples then identified by the API 20E biochemical test and confirmed by the presence of a specific target toxR gene. The detection of virulence genes, thermostable direct haemolysin (tdh) and thermostable-related haemolysin (trh), by the polymerase chain reaction (PCR) showed the presence of only two trh-positive isolates. The assessment of antibiotic susceptibility of the V. parahaemolyticus isolated revealed a complete resistance to colistin, amikacin, penicillin and cefotaxime and a total sensitivity to chloramphenicol, nitrofurantoin and sulfamethoxazole-trimethoprim with a multiple antibiotic resistance index (MAR) ranging from 0.4 to 0.5.

Increased incidence and antimicrobial resistance among Vibrio parahaemolyticus in shellfishes from major fish markets in Cochin, South India: Seafood risk assessment

India remains as a top supplier of value-added seafoods to the global markets. Cochin is one of the leading fishing ports in India contributing to country’s major seafood export. As part of risk assessment, we analyzed the prevalence of multi-drug resistant Vibrio parahaemolyticus; seafood borne gastroenteritis-causing pathogen, in shellfishes collected from major fish markets in Cochin. This bacterial species was initially isolated on Thiosulfate-citrate-bile salts-sucrose agar and HiCrome™ Vibrio agar, further confirmed by detection of V. parahaemolyticus species-specific toxR gene and by 16S r RNA sequencing. A total of 113 confirmed V. parahaemolyticus were recovered. Almost all the strains exhibited resistance towards three or more antibiotics (multiple-drug resistant) and harbored virulence related exoenzymes especially hemolysin (Kanagawa phenomenon); which is indeed a matter of concern. The multiple antibiotic resistance (MAR) index of the isolates ranged from 0.21 to 0.57. Furthermore, our results also indicate a substantial increase in the incidence of the pathogen in seafood from the area compared to previous years. This may pose a risk to the local and international consumers of the seafood. Practicing complete hygiene and adequate cooking is strongly recommended. Regular monitoring of aquaculture areas and fish markets is urged to reduce dissemination of pathogenic V. parahaemolyticus in seafood and to prevent fatal cases of human infection induced by this species in the country.

Presence, Seasonal Distribution, and Biomolecular Characterization of Vibrio parahaemolyticus and Vibrio vulnificus in Shellfish Harvested and Marketed in Sardinia (Italy) between 2017 and 2018

ABSTRACT

In the present study, we investigated the presence, seasonal distribution, and biomolecular characteristics of Vibrio parahaemolyticus and Vibrio vulnificus in samples of bivalve mollusks (Mytilus galloprovincialis, Crassostrea gigas, and Ruditapes decussatus) harvested and marketed in Sardinia (Italy) between 2017 and 2018. A total of 435 samples were submitted for qualitative determination of Vibrio spp., V. parahaemolyticus, and V. vulnificus. Potentially enteropathogenic isolates were detected with biomolecular methods. The overall prevalence of Vibrio spp. was 7.6%. The highest Vibrio prevalence was found in R. decussatus (8.3%). The prevalences of V. parahaemolyticus and V. vulnificus were 2.7 and 4.8%, respectively. Higher prevalences of V. parahaemolyticus and V. vulnificus were found in R. decussatus (4.2%) and C. gigas (6.2%), respectively. Only two pathogenic V. parahaemolyticus strains were recovered (genotypes: tdh- and trh+; tdh+ and trh-), both from M. galloprovincialis. None of the isolates were tdh+ and trh+. Pathogenic Vibrio infections are often underestimated, and human infections are increasing in Europe. European data on the true distribution of Vibrionaceae are scarce, and the results of the present study highlight the need of constant monitoring to update the distribution of pathogenic vibrios.

HIGHLIGHTS

Prevalence and Population Analysis of Vibrio parahaemolyticus Isolated from Freshwater Fish in Zhejiang Province, China

Objectives: The previous researches revealed that Vibrio parahaemolyticus has been detected in freshwater fish samples. However, the molecular characteristics of V. parahaemolyticus isolated from freshwater fish, including pathogenic and pandemic strains, are still unknown. This study aims to characterize and identify molecular properties of the bacterium. In addition, it identifies the source of V. parahaemolyticus from freshwater fish samples in Zhejiang Province, China. Methods: Four hundred and twenty-one freshwater fish samples (from fishing farms, retail markets, and restaurants) and 212 seafood samples (from retail markets) were collected in 10 cities of Zhejiang Province. V. parahaemolyticus strains were isolated from these samples and comparatively analyzed by multilocus sequence typing, serotyping, antimicrobial susceptibility test, and polymerase chain reaction, targeting common toxin genes (tdh, trh) and markers for pandemic strains (orf8, toxRS/new). Results: Sixty-eight V. parahaemolyticus strains were isolated from the 421 freshwater fish samples, and 89 V. parahaemolyticus isolates were identified out of 212 seafood samples. The detection rate of V. parahaemolyticus was significantly different (p < 0.05) between the fishing farms, the retail markets, and the restaurants. The isolates from freshwater fish samples were divided into eight O serotypes with three O3:K6 isolates, which contain three pandemic complexes (tdh⁺, orf8⁺, toxRS/new⁺). A total of 53 different sequence types (STs) were identified among the 68 isolates, including 28 novel STs. Antimicrobial susceptibility results indicated that 76.5% of the strains were resistant to ampicillin. A third (3/9) of the isolates from fishing farm sources shared the same STs with their counterparts from retail markets. Compared with the isolates from the seafood samples collected in the same sampling sites, 13.2% (9/68) freshwater fish isolates overlapped with seafood isolates. Conclusions: Our study showed that V. parahaemolyticus population in freshwater fish is genetically diverse. The V. parahaemolyticus contaminates might have come from both fishing farm sources and cross-contamination from seafood in the closed area at the markets. Freshwater fish may work as a reservoir of pathogenic and pandemic V. parahaemolyticus isolates, indicating potential public health and food safety risks associated with the consumption of freshwater fish.

Evaluation of loop-mediated isothermal amplification assay along with conventional and real-time PCR assay for sensitive detection of pathogenic Vibrio parahaemolyticus from seafood sample without enrichment

The primary reason for foodborne illness is improper seafood safety testing, and hence, an appropriate tool for testing is the key to control the outbreaks. The current study aimed to develop a loop-mediated isothermal amplification (LAMP) assay to detect pathogenic Vibrio parahaemolyticus, important foodborne pathogen, targeting tdh, and trh genes. The specificity of the LAMP assay was good without any false-positive and false-negative results. The assay was highly sensitive and could detect the pathogenic V. parahaemolyticus as low as 1 CFU/reaction in spiked seafood samples and 1 pg of extracted DNA. Out of 62 seafood samples from India’s southwest coastal region tested with LAMP assay, eight (12.9%) were positive for trh, and seven (11.29%) samples were positive tdh gene. LAMP-based on tdh and trh was found to be significantly more sensitive (p < 0.05) than conventional PCR and nearly equal sensitive as real-time PCR (RT-PCR) for the detection of pathogenic V. parahaemolyticus. Our study shows that LAMP assay can be a better approach as a point-of-care (POC) diagnostic tool and could detect pathogenic V. parahaemolyticus on seafood samples directly without enrichment and isolation. The high sensitivity and simplicity make LAMP assay a better alternative method than the conventional method and RT-PCR for the detection of pathogens. LAMP assay can be considered as a good alternative to PCR for the routine detection of pathogenic V. parahaemolyticus in seafood.

Current status of food safety hazards and health risks connected with aquatic food products from Southeast Asian region

Food safety issues associated with aquatic food products become more important with the increasing consumption and followed by its ongoing challenges. The objective of this paper is to review the food safety hazards and health risks related to aquatic food products for the Southeast Asian region. These hazards can be categorized as microplastics (MPs) hazard, biological hazards (pathogenic bacteria, biogenic amines, viruses, parasites), and chemical hazards (antimicrobial, formaldehyde, heavy metal). In different Southeast Asian countries, the potential health risks of aquatic food products brought by food hazards to consumers were at different intensity and classes. Among all these hazards, pathogenic bacteria, antimicrobials, and heavy metal were a particular concern in the Southeast Asian region. With environmental changes, evolving consumption patterns, and the globalization of trade, new food safety challenges are created, which put forward higher requirements on food technologies, food safety regulations, and international cooperation.

Virulence, resistance, and genetic diversity of Vibrio parahaemolyticus recovered from commonly consumed aquatic products in Shanghai, China

Vibrio parahaemolyticus can cause severe gastroenteritis, septicaemia and even death in humans. Continuous monitoring of V. parahaemolyticus contamination in aquatic products is imperative for ensuring food safety. In this study, we isolated and characterized 561 V. parahaemolyticus strains recovered from 23 species of commonly consumed shellfish, crustaceans, and fish collected in July and August of 2017 in Shanghai, China. The bacterium was not isolated from two fish species Carassius auratus and Parabramis pekinensis. The results revealed a very low occurrence of pathogenic V. parahaemolyticus carrying the toxin genes trh (0.2%) and tdh (0.0%). However, high percentages of resistance to the antimicrobial agents ampicillin (93.0%), rifampin (82.9%), streptomycin (75.4%) and kanamycin (50.1%) were found. A high incidence of tolerance to the heavy metals Hg²⁺ (74.7%) and Zn²⁺ (56.2%) was also observed in the isolates. ERIC-PCR-based fingerprinting of MDR isolates (77.5%) revealed 428 ERIC-genotypes, demonstrating remarkable genetic variation among the isolates. The results of this study support the urgent need for food safety risk assessment of aquatic products.

Occurrence and Identification of Pathogenic Vibrio Contaminants in Common Seafood Available in a Chinese Traditional Market in Qingdao, Shandong Province

The investigation of the causative agents for foodborne diseases and subsequent development of preventive steps to control the outbreak and related economic loss is the basic goal and priority of a rational food safety program. The entero-pathogenic Vibrio spp., which are Gram negative bacteria inhabiting estuarine ecosystems, are the major cause of foodborne illness associated with the consumption of raw or undercooked contaminated seafood or shellfish. To survey the Vibrio contamination in sea snails (Neptunea cumingi Crosse and Busycon canaliculatu), a total of 20 samples were collected from traditional market, at Qingdao city in Shandong province, China and analyzed for Vibrio species contamination. Presumptive-positive colonies grown on a specific Vibrio agar-based medium were picked and identified by the VITEK^TM. Vibrio alginolyticus, V. parahaemolyticus, and V. vulgaris were isolated and identified in 11, 8, and 2 seafood samples, respectively. Among the 8 isolates of V. parahaemolyticus. The V. parahaemolyticus isolates were further tested for the tdh, trh, and tlh virulence factors. All the V. parahaemolyticus isolates were tlh-positive, however, all of them were tdh-negative. Interestingly 2 V. parahaemolyticus isolates were positive for trh virulence factor. These results indicated that there is a high incidence of V. alginolyticus and V. parahaemolyticus in sea snails. Therefore, food safety regulations for fishery auction markets should be established to control these species in addition to other Vibrio pathogenic contaminants. Our study provides the first evidence for the prevalence of Vibrio spp. in sea snail samples from traditional market in the Qingdao province of China.

Prevalence and antibiotic resistance patterns of Vibrio parahaemolyticus isolated from different types of seafood in Selangor, Malaysia

Vibrio parahaemolyticus is a foodborne bacterial pathogen that may cause gastroenteritis in humans through the consumption of seafood contaminated with this microorganism. The emergence of antimicrobial and multidrug-resistant bacteria is another serious public health threat worldwide. In this study, the prevalence and antibiotic susceptibility test of V. parahaemolyticus in blood clams, shrimps, surf clams, and squids were determined. The overall prevalence of V. parahaemolyticus in seafood was 85.71% (120/140), consisting of 91.43% (32/35) in blood clam, 88.57% (31/35) in shrimps, 82.86% (29/35) in surf clams, and 80% (28/35) in squids. The majority of V. parahaemolyticus isolates from the seafood samples were found to be susceptible to most antibiotics except ampicillin, cefazolin, and penicillin. The MAR indices of V. parahaemolyticus isolates ranged from 0.04 to 0.71 and about 90.83% of isolates were found resistant to more than one antibiotic. The high prevalence of V. parahaemolyticus in seafood and multidrug-resistant isolates detected in this study could pose a potential risk to human health and hence appropriate control methods should be in place to minimize the potential contamination and prevent the emergence of antibiotic resistance.

Rapid and selective recognition of Vibrio parahaemolyticus assisted by perfluorinated alkoxysilane modified molecularly imprinted polymer film

Molecular imprinting technology offers a means of tailor-made materials with high affinity and selectivity for certain analysts. However, the recognition and separation of specific bacteria in complex matrices are still challenging. Herein, a bacteria-imprinted polydimethylsiloxane (PDMS) film was facilely prepared and modified with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS). Employing Vibrio parahaemolyticus as a model bacterium, the imprinted surface exhibited three-dimensionality cavities with mean size of 1000 × 800 nm in square and 100 nm in depth. After incubation for 2 h with 6 × 10⁷ CFU mL⁻¹ of V. parahaemolyticus, the imprinted polymer film can reach a 62.9% capture efficiency. Furthermore, the imprinted POTS-modified PDMS film based solid phase extraction combined with polymerase chain reaction and agarose gel electrophoresis allows for detecting 10⁴ CFU mL⁻¹ with excellent selectivity in fresh oyster samples. As a result, the developed selective sample pretreatment method using molecular imprinting technology provides a promising platform for separation, identification, and analysis of pathogens.

Molecular imprinting technology offers a means of tailor-made materials with high affinity and selectivity for certain analysts.