A review on comparative analysis of marine and freshwater fish gut microbiomes: insights into environmental impact on gut microbiota

The gut microbiota, which includes prokaryotes, archaea, and eukaryotes such as yeasts, some protozoa, and fungi, significantly impacts fish by affecting digestion, metabolism, and the immune system. In this research, we combine various tasks carried out by various bacteria in the gut of fish. This study also examines the gut microbiome composition of marine and freshwater fish, identifying important bacterial species linked to different biological functions. The diversity within fish species highlights the importance of considering nutrition, habitat, and environmental factors in microbiological research on fish. The ever-changing gut microbiome of the fish indicates that microbial communities are specifically adapted to meet the needs of both the host and its environment. This indicates that the fish can adjust to a specific environment with the help of gut microbiota. This important research is crucial for comprehending the complex relationships between fish and their gut bacteria in different aquatic environments. These discoveries have implications for aquaculture practices, fisheries administration, and the broader ecological processes of both freshwater and marine environments. With further progress in this area of study, the knowledge acquired would offer a valuable standpoint to enhance our comprehension of aquatic microbiology and enhance the sustainability and nutrition of fish resources.

Transcriptomic and microbiome analyses of copepod Apocyclops royi in response to an AHPND-causing strain of Vibrio parahaemolyticus

Copepods are small crustaceans that live in microorganism-rich aquatic environments and provide a key supply of live food for fish and shellfish larviculture. To better understand the host-pathogen interaction between the copepod and Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (VPAHPND), the comparative transcriptome and microbiome analyses were conducted in copepod Apocyclops royi-TH following VPAHPND infection. Transcriptome analysis identified a total of 836 differentially expressed genes, with 275 upregulated and 561 downregulated genes. Subsequent analysis showed that a total of 37 differentially expressed genes were associated with the innate immune system, including 16 upregulated genes related to Toll-like receptor signaling pathway, antimicrobial peptides, and stress response genes, and 21 downregulated genes associated with immunological modulators, signaling molecules, and apoptosis-related proteins. Analysis of the copepod microbiome following VPAHPND infection showed that the microbes changed significantly after bacterial infection, with a reduced alpha diversity accompanied by the increased level of Proteobacteria and decreased levels of Bdellovibrionota, Bacteroidota, and Verrucomicrobiota. The population of Vibrio genera were increased significantly, while several other genera, including Denitromonas, Nitrosomonas, Blastopirellula, Fusibacter, Alteromonas, KI89A_clade, and Ruegeria, were decreased significantly after infection. These findings suggest that VPAHPND infection has a significant impact on the immune defense and the composition of the copepod microbiota.

Edible portions of precooked blue swimming crab: Chemical composition and effect of chitooligosaccharide conjugate and high-pressure processing on microbial inactivation

Different edible portions including meat (lump, claw and backfin) and roe of blue swimming crab (Portunus pelagicus) were analyzed. Both meat and roe had high protein content, but a greater fat content was found in roe. All meats showed higher levels of polyunsaturated fatty acids than roe. Myosin heavy chain and actin constituted as key proteins in meat, but the protein pattern of roe was completely different. Glutamic acid/glutamine were dominant in lump meat, while leucine was prevalent in roe. Meats were fibrous, while roe had a granular structure. Moraxellaceae were dominant in both samples and roe had higher microbial diversity than lump meat. When chitooligosaccharide-catechin (COSC) conjugate and high-pressure processing (HPP) were applied for both lump meat and roe, COSC conjugate (200 ppm) reduced Vibrio spp., and HPP at 500 MPa eliminated all detectable bacteria in both samples. Developed method was promising for enhancing food safety and maintaining quality of precooked crab products.

A case of Vibrio pelagius in a child with inflammatory bowel disease

We describe a rare case of an eleven-year-old child with undiagnosed underlying Crohn's disease who contracted Vibrio pelagius. Though the exact source remained undetermined, the child may have acquired it through infected sea food. Automated system failed to exactly identify the isolated organism; we used detailed biochemical tests for identification. Early diagnosis and identification allowed for efficient treatment plan and the clinical improvement of the child. This case report will give insight to clinical microbiologists for identifying such uncommon bacteria by using biochemical assays in addition to automated systems especially, in those with underlying bowel illnesses.

Genome sequence of Vibrio harveyi strain TUMSAT-2019, isolated from kuruma shrimp, Penaeus japonicus

The Gram-negative bacterium Vibrio harveyi is a serious shrimp pathogen. Here, we present the genome sequence of Vibrio harveyi TUMSAT-2019, which was isolated from a kuruma shrimp (Penaeus japonicus) that originated from a shrimp farm in Okinawa Prefecture. The assembly totaled 5.7 Mbp, consisting of two chromosomes with no plasmid.

A mutualistic model bacterium is lethal to non-symbiotic hosts via the type VI secretion system

What makes a bacterium pathogenic? Since the early days of germ theory, researchers have categorized bacteria as pathogens or non-pathogens, those that cause harm and those that do not, but this binary view is not always accurate. Vibrio fischeri is an exclusive mutualistic symbiont found within the light organs of Hawaiian bobtail squid. This symbiotic interaction requires V. fischeri to utilize a range of behaviors and produce molecules that are often associated with pathogenicity. This juxtaposition of employing "pathogenic" behaviors for a symbiotic relationship led the field to focus on how V. fischeri establishes a beneficial association with its host. In this study, we observe that V. fischeri induces mortality in zebrafish embryos and Artemia nauplii. Non-lethal doses of V. fischeri leads to zebrafish growth delays and phenotypes indicative of disease. Our data also provide evidence that the conserved type VI secretion system on chromosome I (T6SS1) plays a role in the V. fischeri-induced mortality of zebrafish embryos and Artemia nauplii. These results support the hypothesis that the V. fischeri T6SS1 is involved in eukaryotic cell interactions. Despite its traditional view as a beneficial symbiont, we provide evidence that V. fischeri is capable of harming aquatic organisms, indicating its potential to be pathogenic toward non-symbiotic hosts.

Metagenomic insights into the microbial community of the Buhera soda pans, Zimbabwe

BACKGROUND

Soda pans are unique, natural aquatic environments characterised by elevated salinity and alkalinity, creating a distinctive and often extreme geochemistry. The microbiomes of soda pans are unique, with extremophiles such as halophiles, alkaliphiles and haloalkaliphiles being important. Despite being dominated by mostly unculturable inhabitants, soda pans hold immense biotechnological potential. The application of modern "omics-based" techniques helps us better understand the ecology and true extend of the biotechnological potential of soda pan microbiomes. In this study, we used a shotgun metagenomic approach to determine the microbial diversity and functional profile of previously unexplored soda pans located in Buhera, Eastern Zimbabwe. A combination of titrimetry and inductively coupled plasma optical emission spectroscopy (ICP‒OES) was used to perform physico-chemical analysis of the soda pan water.

RESULTS

Physicochemical analysis revealed that the Buhera soda pans are highly alkaline, with a pH range of 8.74 to 11.03, moderately saline (2.94 - 7.55 g/L), and have high carbonate (3625 mg/L) and bicarbonate ion (1325 mg/L) alkalinity. High levels of sulphate, phosphate, chloride and fluoride ions were detected. Metagenomic analysis revealed that domain Bacteria dominated the soda pan microbial community, with Pseudomonadota and Bacillota being the dominant phyla. Vibrio was shown to be the predominant genus, followed by Clostridium, Candidatus Brevefilum, Acetoanaerobium, Thioalkalivibrio and Marinilactibacillus. Archaea were also detected, albeit at a low prevalence of 1%. Functional profiling revealed that the Buhera soda pan microbiome is functionally diverse, has hydrolytic-enzyme production potential and is capable of supporting a variety of geochemical cycles.

CONCLUSIONS

The results of this pioneering study showed that despite their extreme alkalinity and moderate salinity, the Buhera soda pans harbour a taxonomically and functionally diverse microbiome dominated by bacteria. Future work will aim towards establishing the full extent of the soda pan's biotechnological potential, with a particular emphasis on potential enzyme production.

Isolation and Characterization of Infection of Four New Bacteriophages Infecting a Vibrio parahaemolyticus Strain

Bacteria from genus Vibrio continue to be one of the most common threats to aquaculture sustainability. Vibrio spp. have been associated with infectious outbreaks in fish, shrimp, bivalves and even algae farms worldwide. Moreover, several Vibrio spp. are also pathogens that impact human health and are a threat to public health when transferred to consumers through contaminated seafood products. The use of bacteriophages is an evolving technology that could be applied in the treatment of Vibrio spp. either to protect aquaculture farms or to decontaminate seafood, namely bivalves during their depuration. In the present study, bacteriophages vB_VpS_LMAVpS1 (S1) vB_VpS_LMAVpVPP (VPP), vB_VpS_LMAVpSH (SH) and vB_VpS_LMAVpH (H) infecting V. parahaemolyticus were isolated and characterized. All phages presented fast adsorption rates and were able to control V. parahaemolyticus at all multiplicity of infections (MOIs) tested (MOI of 1, 10 and 100), with reductions of more than 4 log CFU/mL being recorded, but only in the presence of divalent cation calcium. The rate of emergence of phage-resistant mutants was very low (1.8 × 10-6 to 3.1 × 10-6). Bacterial phage resistance was not permanent and led to a loss of bacterial fitness. All four phages presented with lysins encoded in their genomes. The results presented provide valuable insights for future studies in the application of these bacteriophages in different scenarios to control, decontaminate or treat bacterial infections or contaminations of V. parahaemolyticus.

Existence of Thermotolerant and Salt-Loving Diarrheagenic Vibrio alginolyticus in Non-Saline Potable Water System: A Novel Finding from India

We present a novel report of abundance of halophilic Vibrio alginolyticus with thermotolerant and enterotoxigenic characteristics from community water system of an inland-focus of India causing diarrheal outbreak as an index pathogen. Though, Vibrio alginolyticus causing diarrhea after exposure to marine water and consumption of seafood was reported globally, its existence in non-saline drinking-water sources with pathogenic viability was unknown. A 'matched-pair-case-control' study identified the primary source of V. alginolyticus infection as 'tap-water' distributed by the municipality, used for drinking (MOR: 8.33; 95% CI 2.51-27.6) and household chores (MOR: 3.75; 95% CI 1.24-11.3). Cardinal toxin gene 'tdh' and other pathogenicity markers viz.tlh, vppC, toxR, VPI, T3SS1 and sxt were detected in V. alginolyticus isolates. Expression potential of the hemolytic genes are demonstrated by hemolysis assay and transcriptome analysis. Altogether 30.55% of isolates exhibited strong hemolytic potential in vitro. RT-PCR revealed uninterrupted virulence gene expression in outbreak strains under heat stress. Surprisingly, ~ 100% of V. alginolyticus from the outbreak focus were sensitive/partially sensitive to all group of antibiotics except β-lactums, carbapenem and quinolones. High drug-sensitivity suggested lack of previous human gut exposure and indicated a fresh dissemination from the environmental niche to the community domain. The maximum likelihood phylogeny depicted multiple clades in V. alginolyticus strains from Pan India sources. Isolated outbreak strains shared common ancestry with the strains from nearby riverine system, a source of 'drinking water' supplied to the affected community, confirming its environmental origin. V. alginolyticus, traditionally a fish-pathogen, is steadily gaining an emerging epidemiological relevance alongside other waterborne diarrheagenic bacteria and its 'thermotolerant' attribute poses additional threat under the canvas of climate change.

Global prevalence patterns and distribution of Vibrio cholerae: A systematic review and meta-analysis of 176,740 samples

This global systematic review and meta-analysis of Vibrio cholerae prevalence, covering environmental, food, animal, and human samples, analysed 111 studies from five databases. The meta-analysis, adhering to standard reporting guidelines, revealed a pooled prevalence of 10.6 % (95 % CI; 8.2 - 13.5; I2 = 99.595 %, p < 0.001) from 176,740 samples, including 27,219 cholera cases. Despite significant publication bias (Egger's test, p = 0.00018), prevalence estimate remained stable in leave-one-out analysis. Subgroup analysis showed prevalence varied by region, with Indonesia highest (55.2 %) and Jordan lowest (0.2 %). Asia continent had the highest prevalence (13.9 %), followed by South America (12.1 %), and lowest in Europe (3.8 %). Environmental samples exhibited the highest prevalence (24.9 %), while human samples had the lowest (7.1 %). The pervasive presence of V. cholerae in environmental resources highlights the persistent risk of global cholera outbreaks, necessitating urgent proactive measures and ongoing surveillance for effective cholera control.

Emerging Vibrio vulnificus-Associated Infections After Seawater Exposure-Cases from the Bulgarian Black Sea Coast

Objectives: The aim of the current report is to present three cases of necrotizing fasciitis and sepsis caused by Vibrio vulnificus on the Bulgarian Black Sea coast. Materials and Methods: Two of the patients are males, 70 and 86 years of age, respectively, and one is an 86-year-old female. Data were collected from the patients' examination records. V. vulnificus was isolated on 5% sheep blood agar from wound and blood samples and identified by the automated system Phoenix M50 (BD, Franklin Lakes, NJ, USA). Antimicrobial susceptibility was tested with two well-known methods (disk diffusion and broth microdilution). Results: All of the patients were admitted to our hospital due to pain, swelling, ulceration, and bullae on the legs and were febrile. They underwent surgery and received intensive care support. One of the patients developed septicemia and septic shock; one of his legs was amputated, but the outcome was fatal. The other patient received immediate approptiate antibiotic and surgical treatment, and the outcome was favorable. The third patient underwent emergency fasciotomy but died a few hours after admission. Conclusions: Global climate change is affecting the distribution of Vibrio spp., and their incidence is expected to increase. It is important to highlight the need for awareness among immunocompromised and elderly patients of the potential threat posed by V. vulnificus infections.

Evaluation of the relationships between physico-chemical parameters and the abundance of Vibrio spp. in blue crabs (Callinectes sapidus) and seawater from the Maryland Coastal Bays

Introduction

Fluctuations in water quality characteristics influence the productivity of blue crabs (Callinectes sapidus), and the risk of human exposure to pathogenic Vibrio species. Thus, this study assessed the prevalence of total and pathogenic/clinical markers of Vibrio parahaemolyticus and Vibrio vulnificus in blue crabs and seawater from the Maryland Coastal Bays (MCBs) and the correlation between Vibrio levels and physicochemical parameters.

Methods

Three to five crabs and 1 L of seawater were collected monthly for 3 years (May 2018 to December 2020) from six sites within the MCBs. Hemolymph and crab tissue were extracted and pooled for each site. Extracted hemolymph, crab tissue, and seawater were analyzed for V. parahaemolyticus and V. vulnificus using the Most Probable Number (MPN) and real-time PCR methods. A one-way Analysis of Variance (ANOVA), correlations, and linear models were used to analyze the data. Akaike Information Criterion (AICc) was evaluated to determine the model that provides the best fit to the data relating to Vibrio concentrations and environmental factors.

Results

Results suggested that environmental factors could influence the growth of Vibrio spp. Both V. parahaemolyticus and V. vulnificus were more prevalent during the warmer months than colder months. Vibrio was more prevalent in crab samples compared to seawater. Vibrio vulnificus concentrations in seawater and hemolymph were positively correlated with temperature (p = 0.0143 seawater) and pH (p = 0.006 hemolymph). A negative correlation was observed between the concentration of V. vulnificus in whole crab (tissue) and dissolved oxygen level (p = 0.0256). The concentration of V. parahaemolyticus in seawater was positively correlated with temperature (p = 0.009) and negatively correlated with dissolved oxygen (p = 0.012).

Discussion

These results provide current information on the spatial and temporal distributions of Vibrio spp. in the MCBs that are useful for implementing more efficient processing and handling procedures of seafood products.

Non-cholera Vibrio spp. invasive infections in the summer following May 2023 flood disaster in Romagna, Italy: a case series

Non-cholera Vibrio spp. includes ubiquitous organisms living in aquatic environments. Their occurrence is associated with global warming and meteorological disasters. In May 2023 the Romagna region, Italy, was affected by severe floods. In the following 15 weeks we observed 5 patients with invasive infections caused by V. vulnificus (3/5) and V. harveyi (2/5). All patients (median age 77 years) had medical comorbidities and shared exposure to seawater. Two patients needed surgery; 2 died. In conclusion, we observed an increased burden of Vibrio spp. invasive infections after May 2023 floods, affecting old patients with predisposing medical conditions.

Public health aspects of Vibrio spp. related to the consumption of seafood in the EU

Vibrio parahaemolyticus, Vibrio vulnificus and non-O1/non-O139 Vibrio cholerae are the Vibrio spp. of highest relevance for public health in the EU through seafood consumption. Infection with V. parahaemolyticus is associated with the haemolysins thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH) and mainly leads to acute gastroenteritis. V. vulnificus infections can lead to sepsis and death in susceptible individuals. V. cholerae non-O1/non-O139 can cause mild gastroenteritis or lead to severe infections, including sepsis, in susceptible individuals. The pooled prevalence estimate in seafood is 19.6% (95% CI 13.7-27.4), 6.1% (95% CI 3.0-11.8) and 4.1% (95% CI 2.4-6.9) for V. parahaemolyticus, V. vulnificus and non-choleragenic V. cholerae, respectively. Approximately one out of five V. parahaemolyticus-positive samples contain pathogenic strains. A large spectrum of antimicrobial resistances, some of which are intrinsic, has been found in vibrios isolated from seafood or food-borne infections in Europe. Genes conferring resistance to medically important antimicrobials and associated with mobile genetic elements are increasingly detected in vibrios. Temperature and salinity are the most relevant drivers for Vibrio abundance in the aquatic environment. It is anticipated that the occurrence and levels of the relevant Vibrio spp. in seafood will increase in response to coastal warming and extreme weather events, especially in low-salinity/brackish waters. While some measures, like high-pressure processing, irradiation or depuration reduce the levels of Vibrio spp. in seafood, maintaining the cold chain is important to prevent their growth. Available risk assessments addressed V. parahaemolyticus in various types of seafood and V. vulnificus in raw oysters and octopus. A quantitative microbiological risk assessment relevant in an EU context would be V. parahaemolyticus in bivalve molluscs (oysters), evaluating the effect of mitigations, especially in a climate change scenario. Knowledge gaps related to Vibrio spp. in seafood and aquatic environments are identified and future research needs are prioritised.

Unveiling the trifecta of cyanobacterial quorum sensing: LuxI, LuxR and LuxS as the intricate machinery for harmful algal bloom formation in freshwater ecosystems

Harmful algal blooms (HABs) are causing significant disruptions in freshwater ecosystems, primarily due to the proliferation of cyanobacteria. These blooms have a widespread impact on various lakes globally, leading to profound environmental and health consequences. Cyanobacteria, with their ability to produce diverse toxins, pose a particular concern as they negatively affect the well-being of humans and animals, exacerbating the situation. Notably, cyanobacteria utilize quorum sensing (QS) as a complex communication mechanism that facilitates coordinated growth and toxin production. QS plays a critical role in regulating the dynamics of HABs. However, recent advances in control and mitigation strategies have shown promising results in effectively managing and reducing the occurrence of HABs. This comprehensive review explores the intricate aspects of cyanobacteria development in freshwater ecosystems, explicitly focusing on deciphering the signaling molecules associated with QS and their corresponding genes. Furthermore, a concise overview of diverse measures implemented to efficiently control and mitigate the spread of these bacteria will be provided, shedding light on the ongoing global efforts to address this urgent environmental issue. By deepening our understanding of the mechanisms driving cyanobacteria growth and developing targeted control strategies, we hope to safeguard freshwater ecosystems and protect the health of humans and animals from the detrimental impacts of HABs.

Bactericidal effect of water-washing methods on Vibrio vulnificus contaminated in a raw fish Konosirus punctatus: water type, temperature, and pH

This study aimed to evaluate a method for effectively reducing Vibrio vulnificus contamination in fish based on the type of washing water and method. Texture profiles and sensory evaluations were performed to determine the effect of the developed method on the quality and preference of the samples. The selected fish sample was Konosirus punctatus, which is mainly consumed in Asian countries. Various factors that could affect the survival rate of V. vulnificus were reviewed, including water type, temperature, exposure time, organic acids, pH, and washing methods. As a result, immersion and washing with filtered water with pH adjusted to 4.0 using acetic acid showed a high bactericidal effect of 2.5 log MPN/100 g. Furthermore, this method showed no statistically significant effect on the texture and sensory characteristics of fish. The results of the present study suggest a simple and effective method for preventing V. vulnificus infection in raw fish.

Harnessing the intragenomic variability of rRNA operons to improve differentiation of Vibrio species

Although the 16S rRNA gene is frequently used as a phylogenetic marker in analysis of environmental DNA, this marker often fails to distinguish closely related species, including those in the genus Vibrio. Here, we investigate whether inclusion and analysis of 23S rRNA sequence can help overcome the intrinsic weaknesses of 16S rRNA analyses for the differentiation of Vibrio species. We construct a maximum likelihood 16S rRNA gene tree to assess the use of this gene to identify clades of Vibrio species. Within the 16S rRNA tree, we identify the putative informative bases responsible for polyphyly, and demonstrate the association of these positions with tree topology. We demonstrate that concatenation of 16S and 23S rRNA genes increases the number of informative nucleotide positions, thereby overcoming ambiguities in 16S rRNA-based phylogenetic reconstructions. Finally, we experimentally demonstrate that this approach considerably improves the differentiation and identification of Vibrio species in environmental samples.

Saturated Iso-Type Fatty Acids from the Marine Bacterium Mesoflavibacter zeaxanthinifaciens with Anti-Trypanosomal Potential

Chagas disease is a Neglected Tropical Disease with limited and ineffective therapy. In a search for new anti-trypanosomal compounds, we investigated the potential of the metabolites from the bacteria living in the corals and sediments of the southeastern Brazilian coast. Three corals, Tubastraea coccinea, Mussismilia hispida, Madracis decactis, and sediments yielded 11 bacterial strains that were fully identified by MALDI-ToF/MS or gene sequencing, resulting in six genera-Vibrio, Shewanella, Mesoflavibacter, Halomonas, Bacillus, and Alteromonas. To conduct this study, EtOAc extracts were prepared and tested against Trypanosoma cruzi. The crude extracts showed IC50 values ranging from 15 to 51 μg/mL against the trypomastigotes. The bacterium Mesoflavibacter zeaxanthinifaciens was selected for fractionation, resulting in an active fraction (FII) with IC50 values of 17.7 μg/mL and 23.8 μg/mL against the trypomastigotes and amastigotes, respectively, with neither mammalian cytotoxicity nor hemolytic activity. Using an NMR and ESI-HRMS analysis, the FII revealed the presence of unsaturated iso-type fatty acids. Its lethal action was investigated, leading to a protein spectral profile of the parasite altered after treatment. The FII also induced a rapid permeabilization of the plasma membrane of the parasite, leading to cell death. These findings demonstrate that these unsaturated iso-type fatty acids are possible new hits against T. cruzi.

Better Performance of Modified Scoring Systems to Predict the Clinical Outcomes of Vibrio Bacteremia in the Emergency Department: An Observational Study

BACKGROUND

Vibrio is a genus of Gram-negative bacteria found in various aquatic environments, including saltwater and freshwater. Vibrio bacteremia can lead to sepsis, a potentially life-threatening condition in which the immune system enters overdrive in response to the disease, causing widespread inflammation and damage to tissues and organs. V. vulnificus had the highest case fatality rate (39%) of all reported foodborne infections in the United States and a high mortality rate in Asia, including Taiwan. Numerous scoring systems have been created to estimate the mortality risk in the emergency department (ED). However, there are no specific scoring systems to predict the mortality risk of Vibrio bacteremia. Therefore, this study modified the existing scoring systems to better predict the mortality risk of Vibrio bacteremia.

METHODS

Cases of Vibrio bacteremia were diagnosed based on the results from at least one blood culture in the ED. Patient data were extracted from the electronic clinical database, covering January 2012 to December 2021. The primary outcome was in-hospital mortality.This study used univariate and multivariate analyses to evaluate the mortality risk.

RESULTS

This study enrolled 36 patients diagnosed with Vibrio bacteremia, including 23 males (63.9%) and 13 females (36.1%), with a mean age of 65.1 ± 15.7 years. The in-hospital mortality rate amounted to 25% (9/36), with 31.5% in V. vulnificus (6/19) and 17.6% in V. non-vulnificus (3/17). The non-survivors demonstrated higher MEDS (10.3 ± 2.4) than the survivors (6.2 ± 4.1) (p = 0.002). Concerning the qSOFA, the survivors scored 0.3 ± 0.5, and the non-survivors displayed a score of 0.6 ± 0.7 (p = 0.387). The AUC of the ROC for the MEDS and qSOFA was 0.833 and 0.599, respectively. This study modified the scoring systems with other predictive factors, including BUN and pH. The AUC of the ROC for the modified MEDS and qSOFA reached up to 0.852 and 0.802, respectively.

CONCLUSION

The MEDS could serve as reliable indicators for forecasting the mortality rate of patients grappling with Vibrio bacteremia. This study modified the MEDS and qSOFA to strengthen the predictive performance of mortality risk for Vibrio bacteremia. We advocate the prompt initiation of targeted therapeutic interventions and judicious antibiotic treatments to curb fatality rates.

Vanadium Accumulation and Reduction by Vanadium-Accumulating Bacteria Isolated from the Intestinal Contents of Ciona robusta

The sea squirt Ciona robusta (formerly Ciona intestinalis type A) has been the subject of many interdisciplinary studies. Known as a vanadium-rich ascidian, C. robusta is an ideal model for exploring microbes associated with the ascidian and the roles of these microbes in vanadium accumulation and reduction. In this study, we discovered two bacterial strains that accumulate large amounts of vanadium, CD2-88 and CD2-102, which belong to the genera Pseudoalteromonas and Vibrio, respectively. The growth medium composition impacted vanadium uptake. Furthermore, pH was also an important factor in the accumulation and localization of vanadium. Most of the vanadium(V) accumulated by these bacteria was converted to less toxic vanadium(IV). Our results provide insights into vanadium accumulation and reduction by bacteria isolated from the ascidian C. robusta to further study the relations between ascidians and microbes and their possible applications for bioremediation or biomineralization.

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

OBJECTIVES

South 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.

METHODS

For 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.

RESULTS

In 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.

CONCLUSIONS

This study demonstrates a high burden of infections caused by non-cholera-causing Vibrio species in South Asia.

Isolation and Characterization of Cholera Toxin Gene-Positive Vibrio cholerae Non-O1/Non-O139 Isolated from Urinary Tract Infection: A Case Report

Background

Urinary tract infection (UTI) caused by V. cholerae is rare and less common. V. cholerae is a Gram-negative bacterium motile using single polar flagellum and, originally, is a waterborne microbe found in aquatic and estuarine environments. Toxigenic V. cholerae is well-known as a causative agent of acute and excessive watery diarrhea after ingesting food and water contaminated with this bacterium.

Case Presentation

A 27-year-old male patient presented to the emergency department on 17th July 2021 with burning micturition, normal vital signs, and no fever, vomiting, or diarrhea. In 2017, the patient complained of short stature and vitamin D deficiency. He was on human growth hormone from January 2018 till October 2019. The diagnosis was V. cholerae Non-O1/non-O139 urinary tract infection (UTI). Considering a urinary tract infection, empirical treatment with Lornoxicam and Ciprofloxacin was initiated, while the result of urine culture was still pending. The patient was discharged on the same day and without any complications.

Conclusion

V. cholerae non-O1/non-O139 is primarily a marine inhabitant and is associated with sporadic cases resulting in cholera-like diarrhea after consumption of contaminated seafood and exposure to seawater. Extraintestinal infection associated with this bacterium should no longer be ignored as this change in the behavior of cholera bacteria mechanism of pathogenicity might be related to some associated virulence genes.

Disease prevalence and bacterial isolates associated with Acropora palmata in the Colombian Caribbean

The decline in Acropora palmata populations in Colombian reefs has been mainly attributed to diseases outbreaks. The population size structure and prevalence of white pox and white band disease were evaluated in six localities of the Colombian Caribbean. Here, we aimed to isolate enteric bacteria and Vibrios from healthy and diseased coral mucus to relate its presence to the health status of Acropora palmata. The isolated bacteria were identified using molecular analyses with the 16S rRNA gene. Larger colonies had the highest percentage of the prevalence of both diseases. The strains that were identified as Vibrio sp. and Bacillus sp. were common in the healthy and diseased mucus of the holobiont. The Exiguobacterium sp. and Cobetia sp. strains isolated from diseased mucus may indicate maintenance and resilience mechanisms in the coral. Enterococcus sp. and other bacteria of the Enterobacteriaceae family were isolated from some localities, suggesting that probably contamination due to poor treatment of domestic wastewater and contributions from river discharges can affect coral health. The spatial heterogeneity of Colombian coral reefs exhibited variability in the bacteria, wherein environmental alterations can trigger signs of disease.

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.

Sources and contamination routes of seafood with human pathogenic Vibrio spp.: A Farm-to-Fork approach

Vibrio spp., known human foodborne pathogens, thrive in freshwater, estuaries, and marine settings, causing vibriosis upon ingestion. The rising global vibriosis cases due to climate change necessitate a deeper understanding of Vibrio epidemiology and human transmission. This review delves into Vibrio contamination in seafood, scrutinizing its sources and pathways. We comprehensively assess the contamination of human-pathogenic Vibrio in the seafood chain, covering raw materials to processed products. A "Farm-to-Fork" approach, aligned with the One Health concept, is essential for grasping the complex nature of Vibrio contamination. Vibrio's widespread presence in natural and farmed aquatic environments establishes them as potential entry points into the seafood chain. Environmental factors, including climate, human activities, and wildlife, influence contamination sources and routes, underscoring the need to understand the origin and transmission of pathogens in raw seafood. Once within the seafood chain, the formation of protective biofilms on various surfaces in production and processing poses significant food safety risks, necessitating proper cleaning and disinfection to prevent microbial residue. In addition, inadequate seafood handling, from inappropriate processing procedures to cross-contamination via pests or seafood handlers, significantly contributes to Vibrio food contamination, thus warranting attention to reduce risks. Information presented here support the imperative for proactive measures, robust research, and interdisciplinary collaboration in order to effectively mitigate the risks posed by human pathogenic Vibrio contamination, safeguarding public health and global food security. This review serves as a crucial resource for researchers, industrials, and policymakers, equipping them with the knowledge to develop biosecurity measures associated with Vibrio-contaminated seafood.

Characterization of Host-Associated Microbiota and Isolation of Antagonistic Bacteria from Greater Amberjack (Seriola dumerili, Risso, 1810) Larvae

Greater amberjack (Seriola dumerili) is a new species in marine aquaculture with high mortalities at the larval stages. The microbiota of amberjack larvae was analyzed using 16S rDNA sequencing in two groups, one added copepod nauplii (Acartia tonsa) in the diet, and one without copepods (control). In addition, antagonistic bacteria were isolated from amberjack larvae and live food cultures. Proteobacteria was the most abundant phylum followed by Bacteroidota in amberjack larvae. The composition and diversity of the microbiota were influenced by age, but not by diet. Microbial community richness and diversity significantly increased over time. Rhodobacteraceae was the most dominant family followed by Vibrionaceae, which showed the highest relative abundance in larvae from the control group 31 days after hatching. Alcaligenes and Thalassobius genera exhibited a significantly higher relative abundance in the copepod group. Sixty-two antagonistic bacterial strains were isolated and screened for their ability to inhibit four fish pathogens (Aeromonas veronii, Vibrio harveyi, V. anguillarum, V. alginolyticus) using a double-layer test. Phaeobacter gallaeciensis, Phaeobacter sp., Ruegeria sp., and Rhodobacter sp. isolated from larvae and Artemia sp. inhibited the fish pathogens. These antagonistic bacteria could be used as host-derived probiotics to improve the growth and survival of the greater amberjack larvae.

Distribution, Prevalence, and Antibiotic Susceptibility Profiles of Infectious Noncholera Vibrio Species in Malaysia

Background

The noncholera Vibrio spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is a paucity of information available on the existence and pathogenicity of this particular noncholera Vibrio spp. in Malaysia in comparison to their counterpart, Vibrio cholera.

Methods

In this study, we extracted retrospective data from Malaysian surveillance database. Analysis was carried out using WHONET software focusing noncholera Vibrio spp. including Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio fluvialis, Vibrio alginolyticus, Vibrio hollisae (Grimontia hollisae), Vibrio mimicus, Vibrio metschnikovii, and Vibrio furnissii.

Results

Here, we report the first distribution and prevalence of these species isolated in Malaysia together with the antibiotic sensitivity profile based on the species. We found that V. parahaemolyticus is the predominant species isolated in Malaysia. Noticeably, across the study period, V. fluvialis is becoming more prevalent, as compared to V. parahaemolyticus. In addition, this study also reports the first isolation of pathogenic V. furnissii from stool in Malaysia.

Conclusion

These data represent an important step toward understanding the potential emergence of noncholera Vibrio spp. outbreaks.

Antibiotic Resistance in Selected Emerging Bacterial Foodborne Pathogens-An Issue of Concern?

Antibiotic resistance (AR) and multidrug resistance (MDR) have been confirmed for all major foodborne pathogens: Campylobacter spp., Salmonella spp., Escherichia coli and Listeria monocytogenes. Of great concern to scientists and physicians are also reports of antibiotic-resistant emerging food pathogens-microorganisms that have not previously been linked to food contamination or were considered epidemiologically insignificant. Since the properties of foodborne pathogens are not always sufficiently recognized, the consequences of the infections are often not easily predictable, and the control of their activity is difficult. The bacteria most commonly identified as emerging foodborne pathogens include Aliarcobacter spp., Aeromonas spp., Cronobacter spp., Vibrio spp., Clostridioides difficile, Escherichia coli, Mycobacterium paratuberculosis, Salmonella enterica, Streptocccus suis, Campylobacter jejuni, Helicobacter pylori, Listeria monocytogenes and Yersinia enterocolitica. The results of our analysis confirm antibiotic resistance and multidrug resistance among the mentioned species. Among the antibiotics whose effectiveness is steadily declining due to expanding resistance among bacteria isolated from food are β-lactams, sulfonamides, tetracyclines and fluoroquinolones. Continuous and thorough monitoring of strains isolated from food is necessary to characterize the existing mechanisms of resistance. In our opinion, this review shows the scale of the problem of microbes related to health, which should not be underestimated.

Independent origins and evolution of the secondary replicons of the class Gammaproteobacteria

Multipartite genomes, consisting of more than one replicon, have been found in approximately 10 % of bacteria, many of which belong to the phylum Proteobacteria. Many aspects of their origin and evolution, and the possible advantages related to this type of genome structure, remain to be elucidated. Here, we performed a systematic analysis of the presence and distribution of multipartite genomes in the class Gammaproteobacteria, which includes several genera with diverse lifestyles. Within this class, multipartite genomes are mainly found in the order Alteromonadales (mostly in the genus Pseudoalteromonas) and in the family Vibrionaceae. Our data suggest that the emergence of secondary replicons in Gammaproteobacteria is rare and that they derive from plasmids. Despite their multiple origins, we highlighted the presence of evolutionary trends such as the inverse proportionality of the genome to chromosome size ratio, which appears to be a general feature of bacteria with multipartite genomes irrespective of taxonomic group. We also highlighted some functional trends. The core gene set of the secondary replicons is extremely small, probably limited to essential genes or genes that favour their maintenance in the genome, while the other genes are less conserved. This hypothesis agrees with the idea that the primary advantage of secondary replicons could be to facilitate gene acquisition through horizontal gene transfer, resulting in replicons enriched in genes associated with adaptation to different ecological niches. Indeed, secondary replicons are enriched both in genes that could promote adaptation to harsh environments, such as those involved in antibiotic, biocide and metal resistance, and in functional categories related to the exploitation of environmental resources (e.g. carbohydrates), which can complement chromosomal functions.

First Steps towards a near Real-Time Modelling System of Vibrio vulnificus in the Baltic Sea

Over the last two decades, Vibrio vulnificus infections have emerged as an increasingly serious public health threat along the German Baltic coast. To manage related risks, near real-time (NRT) modelling of V. vulnificus quantities has often been proposed. Such models require spatially explicit input data, for example, from remote sensing or numerical model products. We tested if data from a hydrodynamic, a meteorological, and a biogeochemical model are suitable as input for an NRT model system by coupling it with field samples and assessing the models' ability to capture known ecological parameters of V. vulnificus. We also identify the most important predictors for V. vulnificus in the Baltic Sea by leveraging the St. Nicolas House Analysis. Using a 27-year time series of sea surface temperature, we have investigated trends of V. vulnificus season length, which pinpoint hotspots mainly in the east of our study region. Our results underline the importance of water temperature and salinity on V. vulnificus abundance but also highlight the potential of air temperature, oxygen, and precipitation to serve as predictors in a statistical model, albeit their relationship with V. vulnificus may not be causal. The evaluated models cannot be used in an NRT model system due to data availability constraints, but promising alternatives are presented. The results provide a valuable basis for a future NRT model for V. vulnificus in the Baltic Sea.

Retrospective analysis of <em>Vibrio</em> spp. isolated from marketed crustaceans using multilocus sequence analysis

The genus Vibrio includes bacteria with different morphological and metabolic characteristics responsible for different human and animal diseases. An accurate identification is essential to assess the risks in regard to aquatic organisms and consequently to public health. The Multilocus Sequence Analysis (MLSA) scheme developed on the basis of 4 housekeeping genes (gyrB, pyrH, recA and atpA) was applied to identify 92 Vibrio strains isolated from crustaceans in 2011. Concatenated sequences were used for the phylogenetic and population analyses and the results were compared with those from biochemical identification tests. From the phylogenetic analysis, 10 clusters and 4 singletons emerged, whereas the population analysis highlighted 12 subpopulations that were well supported by phylogeny with few exceptions. The retrospective analysis allowed correct re-attribution of isolated species, indicating how, for some pathogens, there may be an overestimation of phenotypic identification (e.g. V. parahaemolyticus). Use of the PubMLST Vibrio database highlighted a possible genetic link between Sequence Type (ST) 529 and ST195 (V. alginolyticus) isolated from a human case in Norway during 2018. In addition to the identification of major risk groups of V. cholerae, V. vulnificus and V. parahaemolyticus, MLSA could be a valid support for species considered a minor risk, such as V. alginolyticus, V. mimicus and V. fluvialis. Due to the increased incidence of vibriosis in Europe, the application of different tools will also have to be considered to investigate the possible epidemiological links of the various species in the perspective of Open Science to protect the consumer.

Dataset AqADAPT: Physicochemical Parameters, Vibrio Abundance, and Species Determination in Water Columns of Two Adriatic Sea Aquaculture Sites

Aquaculture provides more than 50% of all seafood for human consumption. This important industrial sector is already under pressure from climate-change-induced shifts in water column temperature, nutrient loads, precipitation patterns, microbial community composition, and ocean acidification, all affecting fish welfare. Disease-related risks are also shifting with important implications for risk from vibriosis, a disease that can lead to massive economic losses. Adaptation to these pressures pose numerous challenges for aquaculture producers, policy makers, and researchers. The dataset AqADAPT aims to help the development of management and adaptation tools by providing (i) measurements of physicochemical (temperature, salinity, total dissolved solids, pH, dissolved oxygen, conductivity, transparency, total nitrogen, ammonia, nitrate, nitrite, total phosphorus, total particulate matter, particulate organic matter, and particulate inorganic matter) and microbiological (heterotrophic (total) bacteria, fecal indicators, and Vibrio abundance) parameters of seawater and (ii) biochemical determination of culturable bacteria in two locations near floating cage fish farms in the Adriatic Sea. Water sampling was conducted seasonally in two fish farms (Cres and Vrgada) and corresponding reference (control) sites between 2019 and 2021 of four vertical layers for a total of 108 observations: the surface, 6 m, 12 m, and the bottom.

Isolation and Characterization of a Novel Vibrio natriegens—Infecting Phage and Its Potential Therapeutic Application in Abalone Aquaculture

Phage-based pathogen control (i.e., phage therapy) has received increasing scientific attention to reduce and prevent the emergence, transmission, and detrimental effects of antibiotic resistance. In the current study, multidrug-resistant Vibrio natriegens strain AbY-1805 was isolated and tentatively identified as a pathogen causing the death of juvenile Pacific abalones (Haliotis discus hannai Ino). In order to apply phage therapy, instead of antibiotics, to treat and control V. natriegens infections in marine aquaculture environments, a lytic phage, vB_VnaS-L3, was isolated. It could effectively infect V. natriegens AbY-1805 with a short latent period (40 min) and high burst size (~890 PFU/cell). Treatment with vB_VnaS-L3 significantly reduced the mortality of juvenile abalones and maintained abalone feeding capacity over a 40-day V. natriegens challenge experiment. Comparative genomic and phylogenetic analyses suggested that vB_VnaS-L3 was a novel marine Siphoviridae-family phage. Furthermore, vB_VnaS-L3 had a narrow host range, possibly specific to the pathogenic V. natriegens strains. It also exhibited viability at a wide range of pH, temperature, and salinity. The short latent period, large burst size, high host specificity, and broad environmental adaptation suggest that phage vB_VnaS-L3 could potentially be developed as an alternative antimicrobial for the control and prevention of marine animal infections caused by pathogenic V. natriegens.

Characterization of Vibrio Populations from Cultured European Seabass and the Surrounding Marine Environment with Emphasis on V. anguillarum

Vibrio species are widely distributed and can be potentially pathogenic to aquatic organisms. In this study, we isolated Vibrio spp. from environmental samples (seawater, sediment, and fish swabs) collected over a three-year period from a fish farm in Mali Ston Bay in the Adriatic Sea, Croatia, and assess their distribution. A total of 48 seawater samples and 12 sediment samples, as well as gill and skin swabs from 110 farmed European seabass, were analysed for the presence of Vibrio. Vibrio strains were identified to the species level by MALDI TOF MS. The analysis revealed that V. alginolyticus was the predominant species in European seabass, followed by V. anguillarum. V. alginolyticus was isolated from the sediments, along with V. gigantis and V. pomeroyi, while V. chagasii, V. cyclitrophicus, V. fortis, V. gigantis, V. harveyi, V. pelagius, and V. pomeroyi were isolated from seawater. V. anguillarum was isolated only twice during two different spring seasons, once from a diseased sea bass and the second time from a healthy sea bass. We analysed these two isolates and found that they differ both genetically and in terms of resistance to antibiotics. Our results confirm the seasonality of vibriosis incidence and the presence of the pathogenic V. anguillarum, which increases the risk of vibriosis.

Improving environmental monitoring of Vibrionaceae in coastal ecosystems through 16S rRNA gene amplicon sequencing

The Vibrionaceae family groups genetically and metabolically diverse bacteria thriving in all marine environments. Despite often representing a minor fraction of bacterial assemblages, members of this family can exploit a wide variety of nutritional sources, which makes them important players in biogeochemical dynamics. Furthermore, several Vibrionaceae species are well-known pathogens, posing a threat to human and animal health. Here, we applied the phylogenetic placement coupled with a consensus-based approach using 16S rRNA gene amplicon sequencing, aiming to reach a reliable and fine-level Vibrionaceae characterization and identify the dynamics of blooming, ecologically important, and potentially pathogenic species in different sites of the northern Adriatic Sea. Water samples were collected monthly at a Long-Term Ecological Research network site from 2018 to 2021, and in spring and summer of 2019 and 2020 at two sites affected by depurated sewage discharge. The 41 identified Vibrionaceae species represented generally below 1% of the sampled communities; blooms (up to ~ 11%) mainly formed by Vibrio chagasii and Vibrio owensii occurred in summer, linked to increasing temperature and particulate matter concentration. Pathogenic species such as Vibrio anguilllarum, Vibrio tapetis, and Photobacterium damselae were found in low abundance. Depuration plant samples were characterized by a lower abundance and diversity of Vibrionaceae species compared to seawater, highlighting that Vibrionaceae dynamics at sea are unlikely to be related to wastewater inputs. Our work represents a further step to improve the molecular approach based on short reads, toward a shared, updated, and curated phylogeny of the Vibrionaceae family.

Investigating the Ability of Growth Models to Predict In Situ Vibrio spp. Abundances

Vibrio spp. have an important role in biogeochemical cycles; some species are disease agents for aquatic animals and/or humans. Predicting population dynamics of Vibrio spp. in natural environments is crucial to predicting how the future conditions will affect the dynamics of these bacteria. The majority of existing Vibrio spp. population growth models were developed in controlled environments, and their applicability to natural environments is unknown. We collected all available functional models from the literature, and distilled them into 28 variants using unified nomenclature. Next, we assessed their ability to predict Vibrio spp. abundance using two new and five already published longitudinal datasets on Vibrio abundance in four different habitat types. Results demonstrate that, while the models were able to predict Vibrio spp. abundance to an extent, the predictions were not reliable. Models often underperformed, especially in environments under significant anthropogenic influence such as aquaculture and urban coastal habitats. We discuss implications and limitations of our analysis, and suggest research priorities; in particular, we advocate for measuring and modeling organic matter.

Aquatic environments: A Potential Source of Antimicrobial-Resistant Vibrio spp

Vibrio spp. are associated with water and seafood-related outbreaks worldwide. They are naturally present in aquatic environments such as seawater, brackish water and freshwater environments. These aquatic environments serve as the main reservoirs of antimicrobial-resistant genes and promote the transfer of antimicrobial-resistant bacterial species to aquatic animals and humans through the aquatic food chain. Vibrio spp. are known as etiological agents of cholera and non-cholera Vibrio infections in humans and animals. Antimicrobial-resistant Vibrio species have become a huge threat in regard to treating Vibrio infections in aquaculture and public health. Most of the Vibrio spp. possess resistance towards the commonly used antimicrobials, including β-lactams, aminoglycosides, tetracyclines, sulfonamides, quinolones and macrolides. The aim of this review is to summarize the antimicrobial resistance properties of Vibrio spp. isolated from aquatic environments to provide awareness about potential health risks related to Vibrio infections in aquaculture and public health.