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ObjectiveIn this paper， the cause of an outbreak of foodborne disease in Huzhou City was analyzed， which may help avoid the recurrence of such incidents. MethodsThrough the field epidemiological investigation， the case definition was formulated and the questionnaire survey was carried out in the case group and the control group. In addition， the chi-square test and logistic regression method were used to identify the factors affecting the outbreak. The patient stool samples， food samples， environmental samples and water samples were collected and used for the laboratory test. The PFGE molecular typing was conducted on the isolated positive strains. ResultsThe number of people exposed during the same period was 410， and the number of possible cases was 18， with an incidence of 4.39%. Generally， the main symptoms were abdominal pain and diarrhea， accompanied by nausea， fatigue， fever and others. For case-control analysis， 17 of the 18 patients were included in the case group， and 19 non-patients were into control group. The results suggested that the risk factors were blanched deep-water shrimp（OR=19.42， 95%CI=1.06‒357.02， P=0.046）and steamed Ao Long （Australian lobster） with garlic and vermicelli （OR=22.01， 95%CI=1.24‒390.70， P=0.035）. According to the laboratory test results Vibrio parahaemolyticus （VP） was positive in 5 cases， and the serum type was is O10∶K4. In the reserved food， VP was positive in the samples of steamed Australian lobster with garlic vermicelli and lamb chops. The serum type was O5∶Kut. ConclusionThis incident was an outbreak of foodborne disease caused by the consumption of wedding food contaminated by VP. The dinner was served by Hotel B on September 17. Moreover， the suspicious foods include the blanched deep-water shrimp and steamed lobster with garlic vermicelli.
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ObjectiveTo ascertain the causes of a food poisoning incident and provide references for the prevention of similar incidents in the future. MethodsCase investigation was conducted through field epidemiological investigation methods， and suspicious meals and foods were searched by the analytical epidemiological method. A food hygiene investigation was conducted in the establishment involved and samples of suspicious food， processing steps， and cases were collected for laboratory testing. ResultsA total of 91 individuals meeting the case definition were identified， resulting in an attack rate of 14.97% （91/608）. The main clinical manifestations included abdominal pain （97.80%）， diarrhea （84.62%）， nausea （62.64%）， vomiting （72.53%）， fever （12.09%）， and increased white blood cells （90.11%）. The peak incidence occurred from 16：00 to 18：00 on June 15. The epidemic curve showed a point-source exposure pattern， with an incubation period of 1 h minimum and 10 h maximum， and an average of 5 h. Analytical epidemiological studies indicated that lunch on June 15 was the suspicious meal （χ2=38.78， P<0.001）， and those who consumed cold-dressed tofu with preserved eggs had a significantly higher risk of falling ill compared to non-consumers （χ2=105.21， P<0.001）. Laboratory testing results revealed Vibrio parahaemolyticus detected in 1 employee’s anal swab and 18 cases’ anal swabs. Staphylococcus aureus was detected in 1 food ingredient and 1 case’s anal swab. The remaining samples tested negative. ConclusionThe cause of this food poisoning incident is Vibrio parahaemolyticus. The cause is the canteen’s supply of cold-dressed tofu with preserved eggs beyond its permissible business scope， potentially leading to cross-contamination during food processing. Regulatory authorities should strengthen routine law enforcement inspections and monitoring. Food service establishments should strengthen food safety awareness， standardize operational procedures in strict accordance with relevant national laws and regulations and food safety standards， and strive to reduce the occurrence of foodborne disease incidents at their source.
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Objective To evaluate the risk of disease of Vibrio parahaemolyticus in aquatic products of raw food animals for population in guangzhou,and determine risk management points. Methods VP quantitative detection was carried out in aquatic products of raw food animals sold in Guangzhou from 2009 to 2022.sQMRA was applied to assess Vibrio parahaemolyticus risk of aquatic products of raw food animals. According to stratified analysis based on the pollution of Vibrio parahaemolyticus and evaluation results,carry out risk management and analysis. Results Among the 98 samples were detected positive of VP from 1 343 samples from 2009 to 2022 , with an overall positive rate of 7.30%.The number of Vibrio parahaemolyticus infection cases caused by eating aquatic products of raw food animals in Guangzhou was 3012. If the proportion of raw food is reduced , the number of Vibrio parahaemolyticus infection cases will be significantly reduced. The number of cases caused by eating raw fash will be reduced from 2128 to 217.The detection rate of Vibrio parahaemolyticus in raw fresh water products was much higher than that in marine products. The probability of infection in the population was higher. The number of cases caused by eating raw fash was the highest.The detection rate of Vibrio parahaemolyticus was higher in raw crustaceans and molluscs. The incidence of Vibrio parahaemolyticus infection cases caused by eating raw fash in the four quarters varied from high to low as such sequence ,4.93×10-5 in the three quarters , 2.53×10-5 in the second quarter , 2.40×10-5 in the first quarter ,1.77×10-5 in the fourth quarter . Conclusion The risk of disease of Vibrio parahaemolyticus in aquatic products of raw food animals was higher. The public health education should be done well. Aquatic products should be cooked thoroughly before eating . Reduce the intake of raw aquatic products and avoid cross contamination. Focus on the risks of summer and autumn seasons and seafood such as crustaceans and molluscs. Concentrate on scientific research on Vibrio parahaemolyticus pollution of fresh water products.
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Objective To investigate the etiological characteristics of food poisoning isolates of Vibrio parahaemolyticus (VP) from 2019 to 2021 in Zhongshan City. Methods A total of 37 strains of Vibrio parahaemolyticus isolated from 8 food poisoning incidents in Zhongshan City from 2019 to 2021 were collected, including 1 residual food isolate and 36 human isolates. The genetic correlation of Vibrio parahaemolyticus food poisoning isolates in this region was analyzed by serological typing, virulence gene detection (TLH, TDH, and TRH), drug sensitivity test, pulsed field gel electrophoresis (PFGE) and multipoint sequence typing (MLST). Results The 37 strains of Vibrio parahaemolyticus were divided into 4 serotypes: O3:K6, O10:K4, O4:K8, and O4:KUT. The tdh+ and trh- were the main virulence genotypes, accounting for 97.30% (36/37). The drug resistance rate of cefazolin was 40.54% (15 strains R, 22 strains I), and no multidrug-resistant strains were found. The 37 VP strains were divided into 23 PFGE types and 6 cluster groups, with correlation coefficients ranging from 60.4%-100%. The multipoint sequencing typing showed that the 37 VP strains were divided into 9 ST types and 3 complex groups, of which ST3 type was the main type (23 strains, 62.1%). Conclusion This study has found that the dominant virulence types of Vibrio parahaemolyticus food poisoning isolates in Zhongshan City from 2019 to 2021 are tdh+ and trh-, and 37 representative strains can be divided into 6 PFGE clusters and 9 ST types with MLST type being mainly ST3. This study has identified the rare serotype O10:K4 which has caused an increase in the proportion of food poisoning events, suggesting that we should strengthen detection and be alert to the risk of continued local epidemics of new rare serotype strains.
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Objective To analyze the infection status and epidemic characteristics of Vibrio parahaemolyticus diarrhea cases in Shanghai in recent years， and to explore its influencing factors and provide a basis for the prevention and control of Vibrio parahaemolyticus infection. Methods Food-borne disease surveillance data in Shanghai from 2017 to 2018 was collected， and the infection status and epidemic characteristics of Vibrio parahaemolyticus were analyzed. χ 2 test and multivariate unconditional logistic regression were used to analyze the factors of Vibrio parahaemolyticus infection. Results Among the food-borne surveillance cases in Shanghai from 2017 to 2018， the positive detection rate of Vibrio parahaemolyticus reached 5.1%， and the positive cases were concentrated in July， August， and September. Those working in the catering industry， migrant workers and workers， and the young and middle-aged people （19‒59 years old） have a high incidence. The results of multivariate analysis showed that dining in Qingpu， Songjiang or Minhang District， occupations of migrant workers and workers， age over 19 years old， the third quarter of a year， and the consumption of aquatic animals and related foods are risk factors for Vibrio parahaemolyticus infection. Conclusion The infection of Vibrio parahaemolyticus in Shanghai is still one of the food-borne diseases that warrant our attention. Strengthening food safety management and supervision， and promoting publicity and education for key populations are important for reducing the risk of infection by this pathogen. At the same time， long-term monitoring of infectious diarrhea cases in this city is necessary to dynamically understand the infection and epidemic characteristics of Vibrio parahaemolyticus ， and adjust the annual prevention and control measures in time.
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Objective To analyze the infection status and epidemic characteristics of Vibrio parahaemolyticus diarrhea cases in Shanghai in recent years， and to explore its influencing factors and provide a basis for the prevention and control of Vibrio parahaemolyticus infection. Methods Food-borne disease surveillance data in Shanghai from 2017 to 2018 was collected， and the infection status and epidemic characteristics of Vibrio parahaemolyticus were analyzed. χ 2 test and multivariate unconditional logistic regression were used to analyze the factors of Vibrio parahaemolyticus infection. Results Among the food-borne surveillance cases in Shanghai from 2017 to 2018， the positive detection rate of Vibrio parahaemolyticus reached 5.1%， and the positive cases were concentrated in July， August， and September. Those working in the catering industry， migrant workers and workers， and the young and middle-aged people （19‒59 years old） have a high incidence. The results of multivariate analysis showed that dining in Qingpu， Songjiang or Minhang District， occupations of migrant workers and workers， age over 19 years old， the third quarter of a year， and the consumption of aquatic animals and related foods are risk factors for Vibrio parahaemolyticus infection. Conclusion The infection of Vibrio parahaemolyticus in Shanghai is still one of the food-borne diseases that warrant our attention. Strengthening food safety management and supervision， and promoting publicity and education for key populations are important for reducing the risk of infection by this pathogen. At the same time， long-term monitoring of infectious diarrhea cases in this city is necessary to dynamically understand the infection and epidemic characteristics of Vibrio parahaemolyticus ， and adjust the annual prevention and control measures in time.
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Objective@#To establish an ultra-sensitive, ultra-fast, visible detection method for Vibrio parahaemolyticus (VP) .@*Methods@#We established a new method for detecting the tdh and trh genes of VP using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a (CRISPR/Cas12a) combined with recombinase polymerase amplification and visual detection (CRISPR/Cas12a-VD).@*Results@#CRISPR/Cas12a-VD accurately detected target DNA at concentrations as low as 10 -18 M (single molecule detection) within 30 min without cross-reactivity against other bacteria. When detecting pure cultures of VP, the consistency of results reached 100% compared with real-time PCR. The method accurately analysed pure cultures and spiked shrimp samples at concentrations as low as 10 2 CFU/g.@*Conclusion@#The novel CRISPR/Cas12a-VD method for detecting VP performed better than traditional detection methods, such as real-time PCR, and has great potential for preventing the spread of pathogens.
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CRISPR-Cas Systems , Nucleic Acid Amplification Techniques/methods , Recombinases/genetics , Vibrio parahaemolyticus/geneticsABSTRACT
ObjectiveTo investigate a foodborne disease outbreak and identify the pathogenic factors in order to prevent the occurrence of similar incidents. MethodsEpidemiological study， on-site food hygiene investigation， and laboratory testing were used to analyze the cause of outbreak in Company A. ResultsA total of 24 confirmed cases were screened out. The major clinical symptoms were diarrhea （100.0%）， stomachache （100.0%）， and vomiting （41.7%）. Samples from 24 patients were tested positive for Vibrio parahaemolyticus， and were homologous by Pulsed field gel electrophoresis （PFGE） phylogenetic study. According to the result of case-control study， eating glass noodles salad at the dinner and supper on July 16th， 2019 was the risk factor （OR=15.71，95%CI：1.90‒129.71）. ConclusionThis foodborne disease outbreak was caused by glass noodles salad cross contaminated with Vibrio parahaemolyticus.
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Vibrio parahaemolyticus, the main pathogen causing seafood related food poisoning worldwide, has strong biofilm formation ability. ToxR is a membrane binding regulatory protein, which has regulatory effect on biofilm formation of V. parahaemolyticus, but the specific mechanism has not been reported. c-di-GMP is an important second messenger in bacteria and is involved in regulating a variety of bacterial behaviors including biofilm formation. In this study, we investigated the regulation of ToxR on c-di-GMP metabolism in V. parahaemolyticus. Intracellular c-di-GMP in the wild type (WT) and toxR mutant (ΔtoxR) strains were extracted by ultrasonication, and the concentrations of c-di-GMP were then determined by enzyme linked immunosorbent assay (ELISA). Three c-di-GMP metabolism-related genes scrA, scrG and vpa0198 were selected as the target genes. Quantitative real-time PCR (q-PCR) was employed to calculate the transcriptional variation of each target gene between WT and ΔtoxR strains. The regulatory DNA region of each target gene was cloned into the pHR309 plasmid harboring a promoterless lacZ gene. The recombinant plasmid was subsequently transferred into WT and ΔtoxR strains to detect the β-galactosidase activity in the cellular extracts. The recombinant lacZ plasmid containing each of the target gene was also transferred into E. coli 100λpir strain harboring the pBAD33 plasmid or the recombinant pBAD33-toxR to test whether ToxR could regulate the expression of the target gene in a heterologous host. The regulatory DNA region of each target gene was amplified by PCR, and the over-expressed His-ToxR was purified. The electrophoretic mobility shift assay (EMSA) was applied to verify whether His-ToxR directly bound to the target promoter region. ELISA results showed that the intracellular c-di-GMP level significantly enhanced in ΔtoxR strain relative to that in WT strain, suggesting that ToxR inhibited the production of c-di-GMP in V. parahaemolyticus. qPCR results showed that the mRNA levels of scrA, scrG and vpa0198 significantly increased in ΔtoxR strain relative to those in WT strain, suggesting that ToxR repressed the transcription of scrA, scrG and vpa0198. lacZ fusion assay showed that ToxR was able to repress the promoter activities of scrA, scrG and vpa0198 in both V. parahaemolyticus and E. coli 100λpir. EMSA results showed that His-ToxR was able to bind to the regulatory DNA regions of scrA and scrG, but not to the regulatory DNA region of vpa0198. In conclusion, ToxR inhibited the production of c-di-GMP in V. parahaemolyticus via directly regulating the transcription of enzyme genes associated with c-di-GMP metabolism, which would be beneficial for V. parahaemolyticus to precisely control bacterial behaviors including biofilm formation.
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Vibrio parahaemolyticus/metabolism , Escherichia coli/metabolism , Bacterial Proteins/metabolism , Transcription Factors/genetics , Gene Expression Regulation, BacterialABSTRACT
Objective:To determine the distribution and epidemic characteristics of Vibrio parahaemolyticus in Jinshan District of Shanghai from 2016 through 2018. Methods:Serotype analysis，examination of virulence genes， including thermolabilehemolysin（TLH），thermostable direct hemolysin（TDH），and TDH related hemolysin（TRH），and antimicrobial susceptibility test and pulsed field gel electrophoresis （PFGE） molecular typing were performed on 218 Vibrio parahaemolyticus isolated from diarrhea patients. Results:A total of 218 strains were divided into 8 groups and 21 serotypes. Of them， 147 strains were serotyped，with O3：K6 as the most common serotype （57.3%）. All tested strains were divided into 25 clusters based on the similarity of 85% and above，in which the dominant cluster was JSVP02，and the total similarity was 56.3%-100.0%. Two hundred and one strains （92.2%） carried tdh gene，13 strains （6.0%） carried trh gene，and 7 strains were negative for both tdh and trh. A total of 35 strains were completely sensitive to 17 kinds of antibiotics，while the remaining 183 strains showed different drug resistance. Conclusion:Vibrio parahaemolyticus isolated from diarrhea patients in Jinshan District from 2016 through 2018 is diverse. Majority of the strains have TDH gene and are resistant to the first generation cephalosporins such as cefazolin and penicillin ampicillin. Construction of regional PFGE molecular typing database will facilitate screening，identification and early warning of high-risk strains.
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Objective To investigate the prevalence of Vibrio parahaemolyticus(VP)in oysters in Jinshan District, Shanghai and make assessment on the risks that may cause, providing the basis for prevention and control of foodborne disease. Methods Raw oyster samples with shells were randomly collected from markets, supermarkets and restaurants in Jinshan District from July to October in 2017. The content of VP in oysters was tested in accordance with the national standard methods. The semi-quantitative risk assessment for VP in oysters was made by Risk Ranger combining with the monitoring results of diet and health status of residents in Jinshan District of Shanghai in 2012-2013. Results The overall positive rate of VP in the 40 oyster samples was 80.0%(32/40). The positive rate of VP in oyster samples from farmer's markets was the highest, 85.7%(12/14), followed by those from restaurants and supermarkets. The relative risk for VP in raw oysters was 63. The probability of illness caused by VP in oysters per day per consumer of interest was 6.85×10-4, and the total predicted patients annual incidence rate in this population was 1 247.8/105. Conclusion The contamination of VP in seafood oysters in Jinshan District is serious. Eating raw oysters is at high risk; consumers are advised to reduce or avoid eating raw oysters, and processing food before eating is an effective method to decrease VP infection. Strengthening surveillance and management is imperative in this regard.
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Objective:To understand the contamination and antimicrobial resistance of Vibrio parahaemolyticus in seafood sold in a place of Zhejiang Province， and to provide basic data for the prevention and control of food-borne diseases caused by V. parahaemolyticus. Methods:V. parahaemolyticus was isolated and identified from seafood according to GB 4789.7—2013 method. The virulence genes were identified by real-time fluorescent PCR， and the antimicrobial sensitivity test was performed by Kirby-Bauer method. Results:V. parahaemolyticus was isolated from 55 of 210 seafood samples. The detection rate was 26.19%， and the detection rates of different species were quite different. None of the 55 isolates contained virulence genes tdh and trh， while all isolates have species-specific genes tlh and toxR. Most isolates were resistant to ampicillin and amoxicillin， with the same antimicrobial resistance rate of 96.36%. All isolates were fully sensitive to ampicillin/sulbactam， tetracycline， ciprofloxacin， levofloxacin， loxacin and chloramphenicol. Conclusion:V. parahaemolyticus contamination is common in sold seafood. The antimicrobial resistance of the isolates has reached a certain level. Monitoring of the pollution status of V. parahaemolyticus in seafood should be strengthened and the aquaculture and clinical use of antibiotics should be standardized.
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Objective:To establish the concatenated DNA sequencing of 16S ribosomal RNA （16S rRNA） and DNA gyrase subunit B （gyrB） gene， and provide evidence for the identification and classification of Vibrio parahaemolyticus （V. parahaemolyticus）. Methods:Typical strains in the genus of Vibrio spp. was selected， such as V. parahaemolyticus， V. alginolyticus and other species for examination of 16S rRNA and gyrB gene as target. Primers were separately designed to amplify these two nucleotide fragments. Phylogenetic analysis was performed using the concatenated sequences. Results:The concatenated 16S rRNA+gyrB nucleotide sequence of V. parahaemolyticus formed a single cluster in the phylogenetic analysis， which identified the typical strains of Vibro spp. at the species level. Conclusion:In our study， an identification method of V. parahaemolyticus is established based on concatenated 16S rRNA+gyrB nucleotide sequencing. It can identify the strains of V. parahaemolyticus at the species level， which may be applied in phylogenetic analysis and contamination tracing of V. parahaemolyticus in food and drug control.
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Objective:To study the transcriptional regulation of pilABCD by the master quorum sensing (QS) regulator OpaR in Vibrio parahaemolyticus. Methods:Total RNAs were extracted from the wild type (WT) and opaR mutant (Δ opaR) strain. Quantitative real-time PCR (qPCR) was employed to calculate the transcriptional variation of pilA (the first gene of pilABCD operon) between WT and Δ opaR. The regulatory DNA region of pilABCD was cloned into the corresponding restriction endonuclease sites of pHRP309 harboring a promoterless lacZ reporter gene. The recombinant pHRP309 plasmid was then transferred into WT and Δ opaR, respectively, to detect the β-galactosidase activity in cellular extracts using a β-Galactosidase Enzyme Assay System (Promega). The primer extension assay was applied to map the transcription start site of pilABCD using the total RNAs extracted from the WT strain as the template. The regulatory DNA region of pilABCD was amplified by PCR, and the over-expressed His-OpaR was purified under native conditions with nickel loaded HiTrap Chelating Sepharose columns (Amersham). Thereafter, the electrophoretic mobility shift assay (EMSA) was applied to analyze the DNA-binding activity of His-OpaR to the target DNA in vitro, and the DNase I footprinting assay was further employed to detect the DNA-binding sites of His-OpaR within the target DNA. Results:The results of qPCR and LacZ fusion assays showed that OpaR activated the transcription of pilABCD, leading to a gradual increase in the expression level of pilA with the extension of culture time. The primer extension assay detected only one transcription start site located at 155 bp upstream of pilA. The results of EMSA and DNase Ⅰ footprinting assays showed that His-OpaR protected two DNA regions located from -246 to -197 bp and -181 to -131 bp upstream of pilA. Conclusions:Vibrio parahaemolyticus OpaR activated the transcription of pilABCD in a direct manner.
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RESUMEN Con el objetivo de determinar la diversidad de variantes patogénicas de Vibrio parahaemolyticus en el Perú durante el periodo 1995-2017, se analizaron 102 genomas peruanos (97 clínicos y 5 ambientales) empleando el esquema de tipificación multilocus y BLASTn para la búsqueda de genes de virulencia. Se identificaron 15 tipos de secuencia diferentes, encontrándose que el genotipo ST3, perteneciente al clon pandémico, fue el más abundante, con 52% (n=53); seguido por el ST120, con 23,5% (n=24); y el complejo clonal CC345, con 11,8% (n=12). Un total de 89 cepas analizadas presentaron genes que codifican la isla de patogenicidad VpaI-7 (87,3%), mientras que 96 presentaron el gen tdh (94,1%), y 6, el trh (5,9%). Durante el periodo evaluado, se resalta la predominancia del ST3, causante de un importante brote en el pasado del Perú, además de otros genotipos patógenos que representan un riesgo latente en salud pública asociado al consumo de alimentos marinos.
ABSTRACT During the period from 1995 to 2017, in order to determine the diversity of Vibrio parahaemolyticus pathogenic variants in Peru, 102 Peruvian genomes (97 from a hospital setting and 5 from an out-of-hospital setting) were analyzed using the multilocus typification scheme and BLASTn in the search for virulence genes. Fifteen different sequence types were identified. It was found that the ST3 genotype, which is found in the pandemic clone, was the most abundant, with 52% (n=53); followed by ST120, with 23.5% (n=24); and the CC345 clonal complex, with 11.8% (n=12). A total of 89 analyzed strains presented genes encoding the pathogenicity island VpaI-7 (87.3%), while 96 presented the tdh gene (94.1%), and 6 the trh gene (5.9%). The ST3 genotype was the predominant one during the evaluated period, this genotype was the cause of a major outbreak in Peru's past history. Other pathogenic genotypes found represent a latent public health risk associated with seafood consumption.
Subject(s)
Humans , Peru , Vibrio Infections , Vibrio parahaemolyticus , Disease Outbreaks , Molecular Typing , Whole Genome Sequencing , Peru/epidemiology , Vibrio Infections/microbiology , Vibrio Infections/epidemiology , Vibrio parahaemolyticus/genetics , Vibrio parahaemolyticus/pathogenicity , Virulence/genetics , Public Health , Epidemiological Monitoring , GenotypeABSTRACT
Objective To investigate and analyze a food borne disease event caused by Vibrio parahaemolyticus (VP) which happened in a company in Shanghai, and to explore the significance of laboratory testing technology in event traceability analysis, then making suggestions on key directions for food-borne disease prevention. Methods On the basis of epidemiological and hygienic investigation, the virulence genes and molecular typing techniques were used for the VP strains detected in the incident. Results A total of 65 patients were consistent with the case definition.The restaurant had no food business license, and its employees had no health certificate.VP was detected in anal swabs of 5 patients and 2 employees, and the PFGE map showed the same. Conclusion The event is suspiciously caused by food contamination from restaurant employees during food processing, assembly or transportation.It is suggested that the management should be improved of all aspects of the restaurant after cooking, and restaurants providing takeaway should be strengthened.
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Objective To find out the causes of food poisoning in a school banquet and identify the pathogenic bacteria, so as to provide evidence for the treatment of food poisoning. Methods A field epidemiological survey was conducted to search for cases, find suspicious poisoning meals and food, and collect cases and food samples for laboratory testing, to determine pathogenic pathogens and virulence genes. The pulsed field gel electrophoresis (PFGE) was applied to identify the homology of the pathogens. Results A total of 92 poisoning cases were found, and the incidence rate was 46.94%. The main clinical manifestations were diarrhea (93.48%), abdominal pain (86.96%), nausea (39.13%), vomiting (34.78%) and fever (17.39%). The median of onset latency was 17 hours. Vibrio parahaemolyticus was detected in samples from 3 patients (2 stools and 1 anal swab). The virulence gene trh was positive and the similarity coefficient of PFGE banding was 97.4%. Pathogenic bacteria were not detected in 10 food samples. The results of the case-control study showed that six types of food were suspicious (OR values were 15.75, 10.14, 8.44, 5.93, 5.56 and 4.71 respectively, P1), including couple lung slices and California bass with extremely high risk of exposure (OR values>10). Conclusion The food poisoning resulted from this enrollment banquet was caused by trh-positive Vibrio parahaemolyticus and no suspicious food was identified (the possibility of contamination by couples' lung slices and California sea bass was high). It is suggested that the supervision and management of catering units and food safety publicity and education should be strengthened to reduce the occurrence of food-borne diseases from the source.
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Vibrio parahaemolyticus is a potentially pathogenic bacterium that occurs naturally in estuarine environments worldwide. This research aimed to investigate the occurrence of V. parahaemolyticus in estuarine environments and determine the virulence profile in an aquaculture environment by molecular techniques and conventional microbiological methods. Sampling was conducted in four estuaries in the State of Ceará (Pacoti, Choró, Pirangi and Jaguaribe), Brazil, between January and April 2009. The analysis included 64 samples of water (n=32) and sediment (n=32) collected from the estuaries. The samples yielded 64 isolates suspected to be V. parahaemolyticus. The isolates were submitted to biochemical identification using a dichotomous key and PCR for the detection of the species-specific tlh gene. Virulence was assessed by testing for urea hydrolysis and ß-hemolysis in erythrocytes (Kanagawa phenomenon) and simultaneous detection of the tdh and trh genes. All but one of the isolates (63/64) were confirmed to be V. parahaemolyticus by genotypic detection of tlh gene. The tdhand trh genes were detected in 57 and 19 isolates, respectively. The Kanagawa test was positive for 51 isolates. Only one isolate was positive for urease. The incidence of tdh/trh-positivity was very high in isolates recovered from the environment. The present study demonstrates the need to increase knowledge of the ecology and pathogeny of V. parahaemolyticus
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Vibrio parahaemolyticus , VirulenceABSTRACT
To analyze compounds in Eleutherine bulbosa (E. bulbosa) (Mill.) Urb. extract and to determine its antibacterial capability against Vibrio parahaemolyticus (V. parahaemolyticus). Methods: E. bulbosa bulb extract was preprared using 96％ ethanol by the maceration method. Phytochemical investigation of E. bulbosa extract was analyzed using GC-MS, spectrophotometry and titrimetry methods. The zone of inhibition was identified by the diffusion agar method. The minimum inhibitory concentration and minimum bactericidal concentration were determined using the plate count method. The inhibitory rate against V. parahaemolyticus was determined by the microdilution method. Cellular leakage was evaluated by spectrophotometry and cellular damage was observed by scanning electron microscopy. Results: GC-MS analysis showed the high compound of the E. bulbosa extract was securixanthone E (7-hydroxy-1,2-dimethoxyxanthone). The compound groups also included fatty acid esters, isoquinolines, naphthalenes, and phenolics. The total phenolic content was (2.50 ± 0.00) mg/g, flavonoid (6.61 ± 0.00) mg/g, and tannin (0.03 ± 0.00)％. The greatest zone of inhibition and inhibitory rate were (11.83 ± 0.06) mm and (91.32 ± 2.76)％, respectively, at 10 mg/mL. The minimum inhibitory concentration was 0.156 mg/mL, while the minimum bactericidal concentration was 10 mg/mL. The E. bulbosa extract caused leakage and cellular damage to V. parahaemolyticus. Conclusions: The E. bulbosa extract possesses inhibitory activities against V. parahaemolyticus and causes cellular leakage and damage.
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Objective To study the biological characteristics of, antibiotic resistance in and ger-micidal efficacy at different temperatures against Vibrio parahaemolyticus ( V. parahaemolyticus) strains isola-ted from different sources in order to provide reference for clinical treatment and prevention. Methods Stool samples from patients with diarrhea and small seafood product specimens from markets were collected and an-alyzed with biochemical identification method, serotyping analysis, drug susceptibility test and germicidal ef-ficacy test at different temperatures. Results There were 107 V. parahaemolyticus strains isolated from 1166 stool samples of patients with foodborne diarrhea with a positive rate of 9. 18％ and 42 from 72 seafood product samples with a positive rate of 58. 30％. V. parahaemolyticus strains isolated from the foodborne diar-rhea cases were divided into eight serogroups and among them, O3 and O4 were the predominant serogroups, accounting for 49. 53％ and 34. 58％, respectively. Most of the O antigens in small seafood products be-longed to serogroups of O4, O1 and O3, and four strains of O3 : K6 were isolated. Results of the drug sus-ceptibility test showed that both of the clinical isolates and marine product isolates were highly resistant to ampicillin and the drug resistance rates were 94. 39％ and 88. 10％, respectively. Antibiotic-sensitive strains to monocyclicβ-lactams, aminoglycosides, quinolones, carbapenems, tetracyclines and sulfonamides accounted for over 90. 00％ or even nearly 100. 00％. There were 17 (15. 89％) clinical strains and three (7. 14％) marine product isolates resistant to three or more kinds of antibiotics. At 80℃, the bactericidal rate for marine product isolates was 85. 71％ in 60 s and reached 100. 00％ in 90 s. At 90℃ and 100℃, these isolates could be completely killed in 40 s and 30 s. It took 120 s, 90 s and 50 s to kill clinical isolates at 80℃, 90℃ and 100℃, respectively. Conclusions This study systematically analyzed and compared the drug-resistant phenotypes of and the bactericidal efficacy at different temperatures on V. parahaemolyticus strains isolated from clinical samples and marine products. It would provide reference for preventing and con-trolling the spread of V. parahaemolyticus and hospital infection and for studying treatment strategies.