Vibrio Species Research Articles

Abundance of Vibrio aestuarianus, water temperature, and stocking density are associated with summer mortality of Pacific oysters in suspended culture

High mortality rates of cultured Pacific oysters (Crassostrea gigas) during the summer months have regularly occurred on oyster farms in British Columbia, Canada over the last 10 years, but little is known about the microbial and environmental conditions that contribute to such mortality events. The objective of the study was to determine correlative factors associated with the onset of a summer mortality event in oysters (mean ± SD shell height: 14.2 ± 0.5 mm) grown in suspended culture at four stocking densities (150, 300, 450, 600 oysters tray−1) from May 11 to September 17, 2018. Variables examined included both biotic (oyster growth, mortality, reproductive development, and microbiome (approximately every week); Vibrio and harmful algal species abundance) and abiotic (temperature, salinity, turbidity, dissolved oxygen, pCO2, pH, and aragonite saturation) ones. Both the absolute abundance of V. aestuarianus and the relative abundance of Vibrio spp. increased with observed oyster mortality and declining health. Mortality was highest on August 12 and associated with a prior period of elevated temperatures (i.e., increasing temperatures from early July to early August) and increased oyster growth/reproductive development. At that time, systemic mixed microbial infections and necrotic gill tissue in histological cross sections were observed in 19% of oysters that appeared healthy macroscopically. Cumulative percent mortalities per tray ranged from 34 to 75%, the highest-density trays having significantly less mortality and smaller shell width, shell length, and gonad length than lower-density trays. This study demonstrates the significant impact of summer mortality on Pacific oysters and highlights the biotic (host growth, reproductive development, and microbiome composition as well as Vibrio spp. abundance) and abiotic (water temperature) factors associated with the observed mortality in this region.

Vibrio species as next-generation chassis for accelerated synthetic biology

Vibrio species as next-generation chassis for accelerated synthetic biology

The Mediterranean Zoanthid Parazoanthus axinellae as a Novel Source of Antimicrobial Compounds

Marine bioprospecting is a dynamic research field that explores the oceans and their biodiversity as noteworthy sources of new bioactive compounds. Anthozoans are marine animals belonging to the Cnidaria phylum characterized by highly specialized mechanosensory cells used both for defence against predators and prey capture. Here, high concentration of cnidocysts have been isolated from the Mediterranean zoanthid coral Parazoanthus axinellae (Schmidt, 1862) and their antimicrobial potential has been investigated. The cnidocyst extract exerted significant antibacterial activity against some human pathogens capable of developing resistance to conventional antibiotics such as Streptococcus agalactiae and Coccus sp., and against several Vibrio species, including some microbial strains for humans and farmed fish, such as Vibrio alginolyticus, Vibrio anguillarum, Vibrio fischeri, Vibrio harveyi, and Vibrio vulnificus. Results have been discussed in light of both the ecological aspects and biotechnological value of the cnidocyst extract in the nutritional, nutraceutical, and pharmaceutical fields.

The analysis of complete genome sequence and comparative genomics of Vibrio parahaemolyticus LF1113 in Hainan

Vibrio parahaemolyticus is a Gram-negative, halophilic and polymorphic coccobacillus. It is world-widely distributed and has resulted in great economic losses since its first appearance. In this study, a pathogenic strain was isolated from diseased pearl gentian grouper and identified as V. parahaemolyticus based on the sequencing results of 16S rDNA gene. In order to gain a comprehensive understanding of this isolation, the whole genome sequencing was conducted. Phylogenetic analysis of the complete genomes of 16 Vibrio species showed that LF1113, ATCC17802, ATCC33787, 2210633, FORC 004, and 160807 were the most closely related. Animal experiments demonstrated that the isolated LF1113 strain was pathogenic in a fish model.This study is the first study to describe the complete genome sequence of a V. parahaemolyticus isolate, which infected pearl gentian grouper from an outbreak in a fish factory farm in Hainan. The results will expand our understanding of genetic characteristics, pathogenesis, diagnostics and disease prevention of V. parahaemolyticus, and lay the foundation for further study.

Differential responses of selectively bred mussels (Perna canaliculus) to heat stress-survival, immunology, gene expression and microbiome diversity.

New Zealand's green-lipped mussel (Perna canaliculus) is an ecologically and economically important species. Marine heatwaves are increasing in frequency around NZ's coastline, and these events are correlated with increased stress and mortality of some aquaculture species. This study aimed to identify general biomarkers of heat stress in P. canaliculus and to assess whether responses differed between genetically distinct selectively bred mussels. We exposed three families of selectively bred mussels (families A, B and C) to three seawater temperature regimes in the laboratory: 1) a "control" treatment (ambient 12°C), 2) a 26°C heat challenge with a subsequent recovery period, and 3) a sustained 26°C heat challenge with no recovery. We investigated whether the survival, immune response (hemocyte concentration and viability, oxidative stress and total antioxidant capacity), hemocyte gene expression and gill microbiome differed between the families during the temperature challenges. In the sustained heat-stress treatment, family A had the highest survival rate (42% compared with 25% and 5% for families C and B, respectively). Gene expression levels significantly shifted during thermal stress and differed between families, with family A more dissimilar than families B and C. Family C had substantially more genes impacted by temperature treatment and timepoint than the other families, while family B had very little genes/pathways that responded to thermal stress. Genes related to heat shock proteins and immune responses (e.g., AIF1, CTSC, TOLL8, CASP9, FNTA, AHCY, CRYAB, PPIF) were upregulated in all families during heat stress. Microbiome species-richness differed between families before and during heat-stress, with family A having a distinctly different microbiome flora than the other families. Microbial diversity changed similarly in all families exposed to prolonged heat-stress, with species of Vibrio and Campylobacter increasing in these mussels. Our study highlights the use of non-lethal sampling of hemocytes as a diagnostic tool to explore the immune response and gene expression of selectively bred mussels, to predict their response to ocean warming. This approach can identify potential thermotolerant candidates for further selective breeding, which may increase the resilience of the mussel aquaculture industry in a warming ocean.

Occurrence of Potentially Pathogenic Bacteria in Commercially Sold Seafood from Misamis Occidental, Philippines

Seafood is a nutritious food that is an enviable component of a healthy diet. Nevertheless, there are health risks associated with the consumption of seafood.
 This study aimed to investigate the occurrence of potentially pathogenic Vibrio spp., Staphylococcus aureus, and Salmonella spp. in 200 seafood samples purchased from several retail outlets in Ozamiz City, Philippines. Different samples analyzed using standard microbiological techniques were clam, shrimp, squid, and fish (anchovy and oil sardines). The Vibrio species identified and isolated were V. parahaemolyticus (47%), V. cholerae (16%) and V. alginolyticus (9%). Thirty percent (30%) of the samples analyzed were positive for S. aureus and 9% of the samples were contaminated with Salmonella sp. The total aerobic plate count mean log10 cfu/g of clams, shrimps, head/gills, intestine of fish (oil sardine, anchovy), and squids were considered as medium to high risk of transmitting pathogenic bacteria. Moreover, the clams and head/gills of oil sardines were considered to be at medium to high risk of transmitting pathogenic V. parahaemolyticus. The findings revealed that seafood samples analyzed microbiologically were loaded with potentially pathogenic bacteria. This result is of public health concern because these organisms are documented as causes of food-borne diseases.

Vibriosis in South Asia: A systematic review and meta-analysis

ObjectivesSouth Asia remains home to foodborne diseases caused by the Vibrio species. We aimed to compile and update information on the epidemiology of vibriosis in South Asia. MethodsFor this systematic review and meta-analysis, we searched PubMed, Web of Science, EMBASE, and Google Scholar for studies related to vibriosis in South Asia published up to May 2023. A random-effects meta-analysis was used to estimate the pooled isolation rate of non–cholera-causing Vibrio species. ResultsIn total, 38 studies were included. Seven of these were case reports and 22 were included in the meta-analysis. The reported vibriosis cases were caused by non-O1/non-O139 V. cholerae, V. parahaemolyticus, V. fluvialis, and V. vulnificus. The overall pooled isolation rate was 4.0% (95% confidence interval [CI] 3.0-5.0%) in patients with diarrhea. Heterogeneity was high (I2 = 98.0%). The isolation rate of non-O1/non-O139 V. cholerae, V. parahaemolyticus, and V. fluvialis were 9.0 (95% CI 7.0-10.0%), 1.0 (95% CI 1.0-2.0%), and 2.0 (95% CI: 1.0-3.0%), respectively. Regarding V. parahaemolyticus, O3:K6 was the most frequently isolated serotype. Cases peaked during summer. Several studies reported antibiotic-resistant strains and those harboring extended-spectrum beta-lactamases genes. ConclusionsThis study demonstrates a high burden of infections caused by non–cholera-causing Vibrio species in South Asia.

Chemical Proteomics Reveals Nε-Fatty-Acylation of Septins by Rho Inactivation Domain (RID) of the Vibrio MARTX Toxin to Alter Septin Localization and Organization

Vibrio species, the Gram-negative bacterial pathogens causing cholera and sepsis, produce multiple secreted virulence factors for infection and pathogenesis. Among these is the multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin that releases several critical effector domains with distinct functions inside eukaryotic host cells. One such effector domain, the Rho inactivation domain (RID), has been discovered to catalyze long-chain Nε-fatty-acylation on lysine residues of Rho GTPases, causing inactivation of Rho GTPases and disruption of the host actin cytoskeleton. However, whether RID modifies other host proteins to exert additional functions remains to be determined. Herein, we describe the integration of bioorthogonal chemical labeling and quantitative proteomics to globally profile the target proteins modified by RID in living cells. More than 246 proteins are identified as new RID substrates, including many involved in GTPase regulation, cytoskeletal organization, and cell division. We demonstrate that RID extensively Nε-fatty-acylates septin proteins, the fourth cytoskeletal component of mammalian cells with important roles in diverse cellular processes. While affinity purification and mass spectrometry analysis show that RID-mediated Nε-fatty-acylation does not affect septin-septin interactions, this modification increases the membrane association of septins and confers localization to detergent-resistant membrane rafts. As a result, the filamentous assembly and organization of septins are disrupted by RID-mediated Nε-fatty-acylation, further contributing to cytoskeletal and mitotic defects that phenocopy the effects of septin depletion. Overall, our work greatly expands the substrate scope and function of RID and demonstrates the role of RID-mediated Nε-fatty-acylation in manipulating septin localization and organization.

Increased abundance of potentially pathogenic Vibrio and a marine heatwave co-occur with a Pacific Oyster summer mortality event

The Pacific Oyster (Crassostrea gigas) is an important aquaculture species, that has been globally affected by “summer mortality” outbreaks. The causes of summer mortality are often unclear, but several contributing factors have been implicated. To better understand the factors contributing to C. gigas summer mortality, we performed a 24 week experiment in tanks filled by a continuous flow of unfiltered surface seawater during a summer mortality high-risk period. Throughout this period, we measured a suite of environmental parameters, with weekly sampling to characterise the bacterial community composition, the abundance and diversity of the Vibrio genus, and the expression of oyster immune response genes. We observed three clear phases of oyster mortality: Phase 1 (day 0 to 75) was characterised by sporadic and low levels (mean < 1% per week) of oyster mortality; Phase 2 (day 82 to 119) involved constant levels of ongoing mortality (mean < 10% per week); and Phase 3 (day 125 to 161) involved a sharp increase in mortality (mean > 10% per week) reaching up to weekly mortality of 51%. The shift between phase 2 and 3 coincided with heavy rainfall and a marine heatwave (MHW) event at our study site, which lasted 13 days, when the average water temperature was elevated by 0.8 °C when compared to the weeks prior and following the MHW, and a maximum water temperature of 27.7 °C was reached. Oyster mortality was positively correlated with the occurrence of the MHW as well as bacterial and Vibrio abundance, and negatively correlated with seawater salinity that decreased from a salinity of 34.6 to 31.4 psu following rainfall events. In addition, the relative abundance of several Vibrio species, including V. campbellii, V. rotiferianus and V. owensii displayed positive correlations to oyster mortality. Shifts in the oyster-associated bacterial community and oyster immunity gene expression profiles occurred in parallel to increased mortality levels, with genes involved in the regulation of antimicrobial peptides (IkB1 and NF-kB p105) significantly over-expressed during high mortality. Overall, we observed a C. gigas mortality event that coincided with a marine heatwave, rainfall event and a shift in bacterial community composition. Our analyses provides further evidence for the putative role of Vibrio in summer mortality events.

DISSEMINATION OF DIARRHEAGENIC BACTERIA IN COMMUNITY-BASED NATURAL WATER SOURCES AND WASTEWATER ENVIRONMENTS: A COMPREHENSIVE ANALYSIS IN UNIVERSITY OF NIGERIA, NSUKKA AND ITS METROPOLIS.

The presence of pathogenic strains abounds in our environment, arising from many sources. The study was aimed at identifying Vibrio species, E. coli, and other coliforms in various water sources within a university setting and its metropolis. Approximately 20 samples from roof-collected rainwater, municipal piped tap water, borehole water and 60 samples of sewage effluent from the central effluent water of University of Nigeria, Nsukka were systematically collected at intervals and subjected to bacteriological analysis. The samples underwent dilutions, and aliquots were inoculated on chromocult and thiosulfate-citrate-bile salts-sucrose (TCBS) agar. Simultaneously, 100 ml of each natural water sample underwent membrane filtration, followed by the inoculation of TCBS agar plates in duplicates. Both sets of culture plates were incubated at 37 °C for 24 h. Further biochemical characterization was performed after microscopy. Susceptibility profile was done using disk diffusion assay. Descriptive statistics were used in the aggregation of the results where necessary. Results revealed that each sample, when plated on chromocult agar, yielded a substantial number of colonies of E. coli (bluish colour) and other coliforms (pink-red colonies). Notably, wastewater gave a maximum yield of Vibrio cholera. Conversely, all significant pathogenic Vibrio species were recovered on TCBS agar inoculated with natural water samples, wastewater and sewage effluent, with isolation rates appearing independent of both time (in weeks) and collection points. Antimicrobial susceptibility studies disclosed that some of the isolates exhibited antibiotic resistance. The study underscores the need to install appropriate measures to mitigate the contamination of the environment. Keywords: Wastewater, Vibrio, Antimicrobial, Chromocult, Pathogen, Sewage

Characterization and genomic analysis of a broad-spectrum lytic phage PG288: A potential natural therapy candidate for Vibrio infections

Vibrio parahaemolyticus, an important zoonotic pathogen, can cause severe diseases and even death in aquatic animals and humans. As the widespread use of antibiotics gradually diminishes their effectiveness, phages, which can selectively lyse bacteria, are garnering increased attention as a valuable alternative antibacterial strategy. This study characterized PG288, a lytic phage utilizing V. parahaemolyticus strain G855 as its host. Morphologically, the phage features a polyhedral head and a long, non-retractable tail. Bactericidal assays revealed that phage PG288 exhibited a strong lytic ability against V. parahaemolyticus strain G855 and demonstrated a broad host range, as evidenced by the ability to infect several distinct Vibrio species. The one-step growth curve indicated a latent period of approximately 50 min for phage PG288, with a burst size of roughly 92 PFU per cell. Additionally, phage PG288 exhibited remarkable stability within a temperature range of 20–50°C and a pH range of 4–10. Genomic analysis unveiled 105 ORFs within phage PG288, notably devoid of genes associated with antibiotic resistance, virulence, and lysogenic activity. Phylogenetic analysis conclusively identified it as a new member of the genus Mardecavirus within the class Caudoviricetes. In summary, this study contributes valuable insights to the phage database, presenting phage PG288 as a promising candidate for phage therapies against Vibrio infections.

Complete genome sequence of a winter season Vibrio facilitates discovery of a novel subclade of cold-adapted species in the albus clade.

In temperate marine climate zones, seasonal changes in water temperature contribute to distinct populations of warm- and cold-water vibrios. We report here the complete genome sequence (BUSCO score=94.8) of the novel strain Vibrio sp. VB16 isolated in late winter from the intertidal zone near Virginia Beach, Virginia, USA with the ability to form colonies at 4 °C. The 5.2 Mbp genome is composed of a large (3.6 Mbp) and small (1.6 Mbp) chromosome. Based on paired average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH), V. sp. VB16 is the same species as V. sp. UBA2437 from a North Sea tidal flat and is closely related to V. sp. DW001 from Antarctic sea ice. Our phylogenomic and bioinformatic analyses placed VB16, UBA2437 and DW001 into a cold-tolerant subclade within the albus clade, along with two non-cold-tolerant subclades. Orthovenn analysis indicated that VB16 and its other albus clade members shared 1544 gene orthologue clusters, including clusters for biosynthesis of polar flagella and tight adhesion pili that predict multiple lifestyles, either free-living or as an opportunistic pathogen within a marine eukaryotic host. The cold-tolerant subclade shared 552 orthologue proteins, including genes known to promote survival in cold or freezing temperatures, such as the eicosapentaenoic acid biosynthetic gene cluster, syp exopolysaccharide gene cluster and novel giant proteins with ice-binding domains. This subclade represents a group of psychrotolerant or 'moderate psychrophile' winter season Vibrio species. The discovery of this subclade opens the door for experimental work on the physiological features, virulence potential and ecological importance of this subclade.

Prevalence investigation of translucent post-larvae disease (TPD) in China

In early 2020, the shrimp farming in China suffered a severe setback due to an outbreak of the translucent post-larvae disease (TPD) in Penaeus vannamei. The emerging disease was caused by a hypervirulent strain of Vibrio parahaemolyticus (VpTPD). Although some progress has been made in understanding virulence factors of VpTPD, the diversity and prevalence of TPD pathogen are still unclear. Therefore, this study was undertaken to systematically investigate the epidemiology of TPD in China. In this study, potentially pathogenic bacteria present in naturally infected shrimp samples were isolated, identified, and preserved firstly. The further investigation showed that different Vibrio species carrying the key virulence genes of VpTPD can infect post-larvae of P. vannamei and cause TPD, revealing the diversity of TPD pathogens, and the pathogenic Vibrio strains has been temporarily named as Vibrio causing TPD (VTPD). In addition, epidemiological surveillance based on TaqMan qPCR detection and histopathology techniques analysis showed that VTPD positive samples were detected in most shrimp aquaculture ponds in different shrimp aquaculture provinces of China, with prevalence rate exceeding 50% in some areas. And seawater cultured species such as P. vannamei and P. japonicus were more sensitive to VTPD and were more likely to be infected or carry it. Freshwater cultured shrimp such as Macrobrachium rosenbergii and Procambarus clarkii may not be affected by VTPD. However, shrimp bait organisms are still at risk of carrying or being infected with VTPD. The result suggests that VTPD is still prevalent and spreading in coastal shrimp farming areas in China, with a high risk of transmission. This effort of present study provided a basic epidemiological understanding as well as important technical insights for prevention and management of emerging shrimp diseases.

Identification of promoter activity in gene-less cassettes fromVibrionaceae superintegrons.

Integrons are genetic platforms that acquire new genes encoded in integron cassettes (ICs), building arrays of adaptive functions. ICs generally encode promoterless genes, whose expression relies on the platform-associated Pc promoter, with the cassette array functioning as an operon-like structure regulated by the distance to the Pc. This is relevant in large sedentary chromosomal integrons (SCIs) carrying hundreds of ICs, like those in Vibrio species. We selected 29 gene-less cassettes in four Vibrio SCIs, and explored whether their function could be related to the transcription regulation of adjacent ICs. We show that most gene-less cassettes have promoter activity on the sense strand, enhancing the expression of downstream cassettes. Additionally, we identified the transcription start sites of gene-less ICs through 5'-RACE. Accordingly, we found that most of the superintegron in Vibrio cholerae is not silent. These promoter cassettes can trigger the expression of a silent dfrB9 cassette downstream, increasing trimethoprim resistance>512-fold in V. cholerae and Escherichia coli. Furthermore, one cassette with an antisense promoter can reduce trimethoprim resistance when cloned downstream. Our findings highlight the regulatory role of gene-less cassettes in the expression of adjacent cassettes, emphasizing their significance in SCIs and their clinical importance if captured by mobile integrons.

Coral mucus as a reservoir of bacteriophages targeting Vibrio pathogens.

The increasing trend in sea surface temperature promotes the spread of Vibrio species, which are known to cause diseases in a wide range of marine organisms. Among these pathogens, Vibrio mediterranei has emerged as a significant threat, leading to bleaching in the coral species Oculina patagonica. Bacteriophages, or phages, are viruses that infect bacteria, thereby regulating microbial communities and playing a crucial role in the coral's defense against pathogens. However, our understanding of phages that infect V. mediterranei is limited. In this study, we identified two phage species capable of infecting V. mediterranei by utilizing a combination of cultivation and metagenomic approaches. These phages are low-abundance specialists within the coral mucus layer that exhibit rapid proliferation in the presence of their hosts, suggesting a potential role in coral defense. Additionally, one of these phages possesses a conserved domain of a leucine-rich repeat protein, similar to those harbored in the coral genome, that plays a key role in pathogen recognition, hinting at potential coral-phage coevolution. Furthermore, our research suggests that lytic Vibrio infections could trigger prophage induction, which may disseminate genetic elements, including virulence factors, in the coral mucus layer. Overall, our findings underscore the importance of historical coral-phage interactions as a form of coral immunity against invasive Vibrio pathogens.

Development of Multienzyme Isothermal Rapid Amplification (MIRA) Combined with Lateral-Flow Dipstick (LFD) Assay to Detect Species-Specific tlh and Pathogenic trh and tdh Genes of Vibrio parahaemolyticus.

Vibrio parahaemolyticus causes severe gastroenteritis in humans after consuming contaminated raw or undercooked seafood. A species-specific marker, the thermolabile hemolysin (tlh) gene, and two pathogenic markers, thermostable-related hemolysin (trh) and thermostable-direct hemolysin (tdh) genes, have been used to identify V. parahaemolyticus and determine its pathogenicity using both PCR and qPCR assays. To enable testing in field conditions with limited resources, this study aimed to develop a simple and rapid method to detect the species-specific (tlh) and pathogenic (trh and tdh) genes of V. parahaemolyticus using multienzyme isothermal rapid amplification (MIRA) combined with a lateral-flow dipstick (LFD). The amplification of the tlh, trh, and tdh genes could be completed within 20 min at temperatures ranging from 30 to 45 °C (p < 0.05). The test yielded positive results for V. parahaemolyticus but produced negative results for nine Vibrio species and eighteen foodborne pathogenic bacterial species. MIRA-LFD could detect 10 fg of DNA and 2 colony-forming units (CFU) of V. parahaemolyticus per reaction, demonstrating a sensitivity level comparable to that of qPCR, which can detect 10 fg of DNA and 2 CFU per reaction. Both MIRA-LFD and qPCR detected seven tlh-positive results from thirty-six oyster samples, whereas one positive result was obtained using the PCR assay. No positive results for the trh and tdh genes were obtained from any oyster samples using MIRA-LFD, PCR, and qPCR. This study suggests that MIRA-LFD is a simple and rapid method to detect species-specific and pathogenic genes of V. parahaemolyticus with high sensitivity.

Molecular Characterization of Vibrio Spp Isolated from Fresh Water Fish in Kafer Elsheikh Government

The most important threatening disease problem facing freshwater aquaculture is Vibriosis that cause water-borne diseases and foodborne gastroenteritis resulted from ingesting of uncooked or undercooked fish products. Also, it is one of the most zoonotic disease which transmitted to human from fish and another aquaculture. This study aimed to isolate different vibrio species from freshwater fish. Microbiological identification of Vibrio species were made using colonial morphology, biochemical characteristics and Identification system for Gram negative bacteria (GN 24) (Diagnostic sro kits) from total of 100 clinically diseased fish samples (Oreochromis niloticus) were collected alive from two various fish farms ( each 50 fish from one farm) from Kafrelsheik Governorate., the prevalence of Vibrio species were noticed in samples tilabia (23/100) 23% which V. parahaemolyticus was found in 6/100 (6%) and V. alginolyticus was detected in 16/100 (16%) and in V. cholera 1/100 (1%), Also we used PCR using 16S rRNA gene-specific for the genus Vibrio , detection of virulence and antibacterial resistance associated genes in v. parahaemolyticus and V. alginolyticus which the most pathogenic vibrio species .The present study also focused on the emergence of Multiple Antibiotic Resistance (MAR) index with the aim of developing strategies to mitigate the potential for infection and ensure effective treatment in the near future.

Detection of Salmonella, Yersinia and Vibrio species in selected species of marine water fish

Marine fish plays an important role in the human diet with an observed increase in the consumption of marine fish. Thus, it is necessary to study the prevalence of pathogens in fish to ensure the safety of fish and fish products. A total of 100 random samples of marine water fish represented by Sardine (Sardina pilchardus), Barbone (Mullus surmuletus), Saurida undosquamis (Mackerel) and Sparus aurata (Denise) (25 of each) were collected from local markets in Alexandria Governorate. Samples were examined bacteriologically immediately after arrival to the laboratory for isolation and identification of Salmonella, Yersinia and Vibrio species. The obtained results revealed that incidence of Salmonella isolated from the examined samples of marine fish species was 16, 8, 4 and 8% in Sardine, Barboni, Mackerel and Dinese, respectively. Serotyping of Salmonella isolated from the examined samples of marine fish clarified the detection of S. Enteritidis, S. Typhimurium and S. Haifa. Also, it was found that the incidence of Yersinia isolated from the examined samples of marine fish species was 44, 36, 24 and 28 % in Sardine, Barboni, Mackerel and Dinese, respectively and the biochemical identification clarified the detection of Y. enterocolitica, Y. frederiksenii, Y. ruckeri and Y. intermedia. Finally, the incidence of Vibrio isolated from the examined samples of marine fish species was 36, 24, 20 and 16 % in Sardine, Barboni, Mackerel and Dinese, respectively and the biochemical identification of the obtained isolates of Vibrio clarified the presence of V. parahaemolyticus and V. cholera. On the basis of the previously mentioned results, Salmonella, Yersinia and Vibrio still constitute common contaminants of marine fish and its presence is very important due to its public health significance, good hygienic measures must be applied to obtain safe marine fish.

Isolation of Vibrio Species from Fresh and Marine Water Fish

The present study aimed to isolate vibrio species from fresh and marine water fish responsible for summer mortality syndrome affecting Cage- cultured grouper species fish (Epinephelus aneus; Epinephelus guaza; Epinephelus alexandrines and Epinephelus caninus) and Lout fish (Argyrosomus regius) farms in Egypt. A total of 250 fish of each species of grouper species fish (E.aneus; E.guaza; E.alexandrines and E.caninus) and Lout fish (Argyrosomus regius) were collected at different times. The fish samples were collected at summer and autumn seasons. The fish samples were 25 from each species in each season. Clinically diseased fish were collected live then rinsed with sterile water and packed in a sterile polystyrene bag. Collected samples were immediately transported in an icebox to the private fish diseases Lab, Alexandria branch. Grouper fish weight between (500 - 1000) g and Lout fish weight (4 - 4.5) Kg. The collected fish samples were submitted directly to the lab for clinical and bacteriological examination. The results cleared that, after the clonical signs, post-mortem examination, isolation and identification on different media and molecular identification (PCR) of the isolated bacteria the main bacteria isolated from Grouper and lout were V. alginolyticus and V. parahaemolyticus. This study concluded that, the Multi stress factors are responsible for summer mortality syndrome affecting cultured grouper species fish (Epinephelus aneus; Epinephelus guaza; Epinephelus alexandrines and Epinephelus caninus) and Lout fish (Argyrosomus regius) in Egypt; thermal stress associated with heatwaves is the main predisposing factor. Co-infections are very common in nature and occur when Cage- cultured grouper species fish (E.aneus; E.guaza; E.alexandrines and E.caninus) and Lout fish (A. regius) are infected by two or more different pathogens either by simultaneous or secondary infections

Molecular identification and antibiotic resistance profiling of Vibrio spp. in diarrhoeal patients from Dinajpur, Bangladesh

This research aimed to characterize Vibrio species from cholera-suspected patients in three hospitals in Dinajpur. We collected 36 stool samples and identified Vibrio spp. using cultural, morphological, and biochemical tests. The highest prevalence was observed in children (18.18%), compared to adolescents (0%), adults (16.67%), and senior adults (16.67%). Cultural identification revealed yellow colonies on TCBS agar, hemolytic colonies on blood agar, pale non-lactose fermenting colonies on MacConkey agar, and white, opaque colonies on nutrient agar. Gram staining showed gram-negative, curved rod-shaped bacteria. Biochemical tests indicated positive reactions for oxidase, catalase, MR, TSI, citrate utilization, MIU, and indole, while VP was negative. Molecular characterization by PCR and gel electrophoresis using 16S rRNA primers confirmed the presence of Vibrio spp. Antibiotic sensitivity testing showed that isolates were sensitive to cotrimoxazole-25µg (21 mm to 30 mm), neomycin-30µg (22 mm), gentamycin-10µg (15 mm), streptomycin-10µg (20 mm), and tetracycline-30µg (17 mm), but resistant to penicillin, mecillinam, and amoxicillin. These findings suggest streptomycin and cotrimoxazole as effective drugs for controlling cholera.