Category Archives: vibrio cholerae

Research – Prevalence, genomic characterization, and risk assessment of human pathogenic Vibrio species in seafood

Journal of Food Protection

Pathogenic Vibrio spp. are largely responsible for human diseases caused through consumption of contaminated seafood. The aim of this study was to determine the prevalence, population densities, species diversity and molecular characteristics of pathogenic Vibrio in various seafood commodities and its associated health risks. Samples of finfish and shellfish (oysters and sea urchins) were collected from different regions and analyzed for Vibrio using the Most Probable Number (MPN) technique. Genomic DNA of putative Vibrio isolates was analyzed by whole genome sequencing (WGS) for taxonomic identification and identification of genes responsible for virulence and antimicrobial resistance. The risk of vibrio-related illnesses due to the consumption of contaminated seafood was assessed using Risk Ranger. Population densities of presumptive Vibrio fell in the range of 2.6 – 4.4 Log MPN/g and correlated with seasonality, with the summer season favoring significantly (p < 0.05) higher Vibrio counts. A total of 15 Vibrio isolates were identified as V. alginolyticus (5), V . parahaemolyticus (6), V. harveyi (2) or V. diabolicus (2). Two of the six V. parahaemolyticus isolates (ST 2504 and ST 2505) originating from oysters were found to be either tdh + or trh + and thus considered a human pathogen due to elaboration of Thermostable Direct Hemolysin (TDH) or TDH-related hemolysin (TRH). In addition to virulence genes, the shellfish isolates also harbored genes encoding resistance to multiple antibiotics including tetracycline, penicillin, quinolone and beta-lactam antibiotics, thus arousing concern. The risk assessment exercise pointed to an estimated 21 annual cases of V. parahaemolyticus -associated gastroenteritis in the general population attributed to consumption of contaminated oysters. This study highlights not only the wide prevalence and diversity of Vibrio in seafood, but also the potential of certain strains to threaten public health.

Research – Epidemiological and microbiological investigation of a large increase in vibriosis, northern Europe, 2018


Food Illness

The habitat of  spp. bacteria is fresh and brackish water with moderate salinity. Non-toxigenic , as well as several human pathogenic non-cholera  species, including  and , cause vibriosis after seawater exposure or consumption of contaminated seafood [1]. Clinical manifestations range from mild gastroenteritis and otitis to wound infections that may lead to severe necrotising fasciitis and septicaemia with a potentially fatal outcome [25].

The Baltic Sea region is one of the areas where increasing numbers of cases related to  species causing vibriosis (VCV) have been reported in the last decades [6]. Several studies have shown how the occurrence of heatwaves, which lead to an increase in sea surface temperature, are linked with an increase in the number of reported vibriosis cases [4,712]. For instance, the years with an especially warm summer in the Baltic Sea region, 2006, 2010 and particularly 2014 (the warmest year in historical records at the time), were also the years with the largest number of vibriosis cases reported [6,11].

However, there is a notable gap in surveillance data for vibriosis since it is not a notifiable disease in the majority of European countries [1,6]. Therefore, the aim of this multi-country study was to describe the epidemiology of vibriosis cases in countries bordering the North and Baltic Seas area during the exceptionally warm year of 2018 [13,14], in order to investigate the extent of these infections in the study countries, map their genetic diversity, understand the predictors for developing severe vibriosis, and propose recommendations for public health measures.

Nepal – Nepalese cholera outbreak: Kathmandu bans Panipuri

World Akkam

Kathmandu, June 26: Kathmandu, the capital of Nepal, is currently facing another outbreak of cholera. As of Sunday, at least 12 people have been infected with the disease, and authorities are struggling to contain the outbreak.

Cases of cholera have been found in several parts of the city, and health authorities have not yet identified the source. It was found that the water sources in many areas contained Vibrio cholerae.

Meanwhile, Kathmandu’s affiliated city, Lalitpur, has banned the sale of Panipuri and chat from Sunday for fear of cholera.

Lalitpur Metropolitan City (LMC) has decided to stop selling and distributing Panipuri and Chatpate in big cities from Saturday. LMC has banned the sale of Panipuri and Chapati, claiming that Vibrio cholerae was found in the water used in Panipuri.

RASFF Alerts – Vibrio cholerae – Shrimps


Presence of Vibrio cholerae in shrimps from Ecuador in Spain


Vibrio cholerae in shrimps from Ecuador in Spain

RASFF Alert – Vibrio cholerae – Prawns


Vibrio cholerae in prawns from Ecuador in Spain

Research – Vital Surveillances: Phylogenetic Analysis of Serogroup O5 Vibrio cholerae that Caused Successive Cholera Outbreaks — Guangdong Province, China, 2020–2021

China CDC

Food Illness

  • Abstract

    IntroductionGastroenteritis caused by non-O1/non-O139 Vibrio cholerae exhibited an increasing trend in recent years in China. Whole genome sequence (WGS) data could play an important role both in the identification of the outbreaks and in the determination of the serogroup. Here, we present the employment of WGS data in the investigation of two outbreaks caused by non-O1/non-O139 V. cholerae in Guangdong, China, 2020–2021.

    MethodsWe obtained the whole genome sequence of 66 V. cholerae strains isolated in two outbreaks with next generation sequencing technology. We retrieved the publicly available WGS data of non-O1/non-O139 V. cholerae from public database. We used a pipeline integrated in China Pathogen Identification Net (PIN) to complete the phylogenetic analysis.

    ResultsTwo outbreaks caused by non-O1/non-O139 V. cholerae were identified using WGS data. These V. cholerae strains were determined as serogroup O5. Type 3 and 6 secretion systems were detected in these serogroup O5 strains. These serogroup O5 strains belonged to sequence type (ST) 88.

    ConclusionsOur analysis indicated the risk of non-O1/non-O139 V. cholerae of leading to outbreaks of diarrheal diseases. The application of genomic data played important role in the identification of the serogroup of non-O1/non-O139 V. cholerae in the lack of antiserum, which gave an example of the application of genome data in disease surveillance and public health emergency response.

  • Vibrio cholerae consists of more than 200 serogroups. The classification of serogroups is based on the O antigen of the lipopolysaccharide (LPS) (1). The classical method of serogroup determination is based on the immune agglutination reaction between the O antigen and the corresponding specific antiserum. The molecular mechanisms of different serogroups are based on the variation in structure of O-antigen polysaccharide (O-PS) coding sequence (2). Therefore, the phenotype of O-antigen is correlated with the molecular type of O-PS coding sequence. Till now, only serogroup O1 and O139 V. cholerae caused cholera epidemics and pandemics (3). V. cholerae does not belong to serogroup O1 and O139 and are designated as “non-O1/non-O139” V. cholerae. Usually, these non-O1/non-O139 V. cholerae only cause sporadic infections and seldomly cause outbreaks (4). Several kinds of toxins, such as a heat-stable toxin, cholera toxin, and other enterotoxins, have been detected in the non-O1/non-O139 V. cholerae that caused an outbreak. Except for the toxins, secretion systems, for example type 3 secretion system (T3SS) and type 6 secretion system, have been detected in some V. cholerae strains that caused cholera outbreaks (5).

    In China, toxigenic serogroup O1 and O139 V. cholerae strains were rarely isolated after 2010 (6). In contrast, sporadic cholera cases even small scale of outbreaks caused by non-O1/non-O139 V. cholerae were reported from time to time (4). Here we report successive cholera outbreaks caused by non-toxin-producing serogroup O5 V. cholerae in 2020 and 2021 in Guangdong Province, China.

Research – Emergence of non-choleragenic Vibrio infections in Australia

1 Health


Vibrio infection was rarely reported in Tasmania prior to 2016, when a multistate outbreak of Vibrio parahaemolyticus associated with Tasmanian oysters was identified and 11 people reported ill. Since then, sporadic foodborne cases have been identified following consumption of commercially- and recreationally-harvested oysters. The increases in both foodborne and non-foodborne Vibrio infec-tions in Tasmania are likely associated with increased sea water temperatures. As oyster production increases and climate change raises the sea surface temperature of our coastline, Tasmania expects to see more vibriosis cases. Vibriosis due to oyster consumption has been reported in other Australian states, but the variability in notification requirements between jurisdictions makes case and outbreak detection difficult and potentially hampers any public health response to prevent further illness.

RASFF Alert – Vibrio cholerae – Frozen Prawns


Vibrio cholerae (presence /25g) in frozen prawns (Litopenaeus vannamei) from Ecuador in Spain

Research – Editorial: Vibrio Species in the Food Processing Chain

Frontiers in Microbiology

Food Illness

Editorial on the Research Topic
Vibrio Species in the Food Processing Chain

Rising concern about the foodborne illnesses caused by pathogenic Vibrio species (mainly V. parahaemolyticus, V. cholera, and V. vulnificus) has led to a strengthening of research on the characterization of the presence of the genus in food matrices, virulence genes, pandemic markers, and the correlation between clinical and environmental isolates from different ecosystems. The emergence of antimicrobial resistance strains (AMR) in Vibrio spp. may produce a decrease in the effectiveness of commonly used antibiotics, thus posing a threat to public health. Progress in genomic studies has identified motile elements implied in gene transfer that may give birth to developing surveillance strategies for risk mitigation. The development of new infection models that can predict the pathogenesis of Vibrio spp. and the use of high-throughput sequencing techniques for serogroup genes may be useful tools for understanding molecular pathways and the infectivity of Vibrio spp. food isolates. In this Research Topic, different approaches, aiming at characterizing Vibrio spp. from aquaculture, marine, and vegetable ecosystems, together with the evaluation of microbial behavior and the development of new infection and serogroup models, are shown.

A mini-review by Dutta et al. discusses the role and antimicrobial resistance of pathogenic Vibrio spp. They present potential sources of antibiotic resistance genes for Vibrio spp., including the horizontal gene transmission from other pathogens as the main route. This has shown the genetic basis of the emergence of multidrug and extensively multidrug resistant Vibrio spp. through different types of highly mobile elements that can be extensively propagated among bacteria. The use of phage or probiotic therapies as alternative treatments for the inactivation of antibiotic resistant species of Vibrio may be helped by the maintenance of good hygiene practices and processing technologies to protect public health.

Antibiotic resistance genes can also originate from the environment, such as wastewater effluents or sediments in marine or aquaculture habitats. In this regard, Siddique et al. studied the characterization of pathogenic V. parahaemolyticus in a fish farm ecosystem (tilapia, rui, and shrimp). Among the 216 samples, 60.2% were positive for the pathogen, including 323 isolates of which 17 harboured the trh virulence gene gene. They confirm the presence of resistant strains to amoxicillin, ampicillin, and penicillin. Pathogenicity was further confirmed by the fluid accumulation in the ileal loop of rabbits being O8: KUT, the most predominant pathogenic serotype.

The presence and characterization of V. parahaemolyticus and V. vulnificus in marine and estuarine environments was studied by da Silva et al. They found 150 isolates of V. parahaemolyticus, including 52 positives for trh gene, and 129 of V. vulnificus from water and blue crab samples. PFGE and agglutination tests were used for molecular subtyping and determination of antibiotic resistance. The study showed the high presence of the O5 pathogenic serotype, together with the multidrug resistant isolates (41%) and the high genetic diversity of both Vibrio species, as no correlations were found among the sampling sites, antimicrobial resistance profiles, and pathogenicity.

The associated presence of Vibrio spp. in water ecosystems may underestimate their origin from other environmental and food sources. Ready-To-Eat vegetables can harbor pathogenic Vibrio spp. if poor manufacturing, hygiene, and storage practices are followed. Igbinosa et al. evaluated the presence of V. parahaemolyticus in minimally processed vegetables. Among the 63 isolates, they found microbial counts from 1.5 to 1,000 MPN/g and drug resistant isolates to ampicillin and cefotaxime mainly (>60%). They studied the biofilm formation finding that 23.8% of the isolates were strong biofilm producers. Regarding the presence of virulence genes, 100, 14.3, and 31.8% of the isolates harbored the toxR gene, trh, and tdh determinants, respectively.

The microbial behavior of Vibrio spp. can be quantified with predictive models. Posada-Izquierdo et al. investigated the fate of a Vibrio spp. cocktail inoculated in lye-treated table olives for 22 days. A predictive growth model was developed as a function of salt concentration (2–12%) and pH (4–9) using a synthetic medium and table olive brines. They found a higher effect of salt concentration than of pH for the growth inhibition of Vibrio spp. However, they were not able to proliferate in the table olives during fermentation, highlighting that phenolics compounds could exert a clear antimicrobial effect.

The disposal of reliable models to predict the pathogenesis of Vibrio spp. are increasingly needed since the use of virulence markers could not fully elucidate the presence of long-standing virulence indicators. This was demonstrated by Santos et al. using clinical and environmental V. parahaemolyticus isolates in two systemic infection models, namely mice and Galleria mellonella larvae. Interestingly, non-pathogenic environmental isolates produced lethal infections regardless of their source, serotype, and genotype (tdh, orf8, toxRSnew, and vpadF). A high correlation was found in the assayed models, supporting that G. mellonella larvae can be used as an alternative model to study the pathogenesis of V. parahaemolyticus.

Recently, the use of high-throughput sequencing technologies has aided researchers in deciphering the genome of different species. This was essential to provide complete knowledge of the molecular and metabolic pathways of microorganisms and the identification of virulence gene clusters. Bian et al. have developed VPsero, a rapid serotyping tool for V. parahaemolyticus using serogroup specific genes obtained from whole-genome sequencing data. The algorithm, based on the comparison of lipopolysaccharide and capsular polysaccharide gene clusters covered 43 K and 12 O serogroups. The authors showed the high sensitivity and specificity of the tool (>0.91), though limitations could be faced in future studies, such as the addition of new serogroups, the verification of the quality of assembled genomes and the availability of short reads.

This Research Topic presents a collection of manuscripts highlighting relevant findings in the pathogenesis of Vibrio spp. in the food chain and suggests future directions for research, enabling progress in the development of novel analytical methods and surveillance actions to mitigate the emerging risk posed by these human pathogens.

India – Operation Vibrio launched in Kozhikode to tackle waterborne diseases

The Hindu

Operation Vibrio, an action plan to tackle the recurring incidents of food poisoning and waterborne diseases, has been launched in Kozhikode. The Health Department has also issued an alert against cholera in the district.

District Medical Officer Ummer Farooque said on Tuesday that the effort was to detect diseases such as cholera, shigella, amoebiasis, typhoid and jaundice that spread through contaminated food and water. As many as 17 cases of food poisoning had been reported in the district between February and November this year. As many as 257 people were infected and two died. Family events and wedding receptions and the food supplied in shops and hostels were reported to be the source of the infection. Some others took ill through having ice cream and fruit juices. The presence of bacteria such as vibrio cholerae, coliform, and e-coli had been found in water sources in some parts of the district as well.