Diagnosis, Management, and Future Control of Cholera

Chemical synthesis elucidates the absolute configuration and key antigenic epitope of Vibrio cholerae serotype O100 O-antigen

The emergence of drug-resistant strains of Vibrio cholerae, coupled with the current limitations of oral vaccines, underscores the urgent need for the development of new vaccines. The O-antigen of V. cholerae serotype O100 has emerged as a promising candidate for vaccine development. To investigate the absolute configuration of 3,5-dihydroxyhexanoyl (dHh) and to evaluate the structure-activity relationship of the O-antigen trisaccharide repeating unit, we completed total synthesis of four potential trisaccharide isomers, along with 11 additional oligosaccharide fragments of the O-antigen. Stereoselective reduction was used for the synthesis of dHh, and the efficient assembly of dHh and (R)-3-hydroxybutanoyl (RHb) was achieved through a post-glycosylation modification strategy. Through NMR analysis, the absolute configuration of dHh was assigned 3S,5S. Glycan microarray screening indicated that RHb is essential for the antigenicity of O-antigen. The nonreducing end disaccharide 59 may serve as the minimal antigenic epitope. These findings are an important step toward the design of semi-synthetic carbohydrate vaccines against V. cholerae.

Non-toxigenic Vibrio cholerae - just another cause of vibriosis or a potential new pandemic?

Although nontoxigenic Vibrio cholerae usually stands in the shadow of the two serogroups (O1 and O139) that cause pandemic cholera, its role in human pathology is increasingly recognized and described in the literature. The habitat of these pathogens is brackish seawater or even freshwater, and the infections caused by them include contact with these waters or consumption of seafood originating in this habitat, which is constantly expanding because of global warming. This habitat extension is a typical example of climate change's impact on infectious diseases. Although nontoxigenic Vibrio cholerae strains are rarely capable of producing the classical cholera toxin, they possess many other virulence factors, can secrete various other toxins, and thus produce illnesses that are sometimes even severe or life-threatening, more frequently in immunocompromised patients. Vibriosis may manifest as gastrointestinal illnesses, wounds, skin or subcutaneous tissue infections, or septicemia. To establish the correct etiological diagnosis for these infections, a high index of suspicion must be maintained, as the diagnostic techniques require targeted investigations and specific collection and transportation of the samples. Empiric treatment recommendations are available, but owing to the increasing resistance of this pathogen, susceptibility testing is needed for every diagnosed case. We intend to raise awareness regarding these infections, as they tend to be more frequent than they were in the past and to appear in areas where they had not been recognized before.

Time to invest in cholera

The recent surge in cholera cases globally calls for urgent evaluation of current approaches to prevention and control of the disease. Malawi was one of the worst affected countries in 2022-2023 with the highest number of deaths due to cholera in the world. In this personal view, we look at Malawi as a case example to illustrate how current approaches lack sufficient investment. We review the history of cholera in Malawi and compare previous outbreaks to the 2022/23 outbreak. We discuss contributing factors to the outbreak including a lack of investment in water, sanitation and hygiene (both historically and currently), human resource constraints, and the market structures which make accessing oral cholera vaccine challenging both in the midst of an ongoing outbreak and as a preventative approach. We call for international action to address the economic and structural challenges underlying cholera persistence and propose solutions to prevent future epidemics and to eliminate cholera as a public health threat.

Spatio-temporal patterns of cholera outbreak in rural settings of Ethiopia, 2023

Objectives

The aim of this study was to assess the spatio-temporal pattern of cholera in rural settings of Ethiopia.

Methods

A spatiotemporal analysis of daily cholera cases in 59 Kebeles across 7 districts in the Gedeo zone from April 2 to November 18, 2023, obtained from the Gedeo Zone Health Department, was conducted. The global Moran's I statistic was used for spatial autocorrelation analysis, and the retrospective space-time scan statistic was used to analyze spatiotemporal clusters of cholera.

Results

Throughout the outbreak, 792 cholera cases were reported, corresponding to an annual incidence of 169.4 per 100,000 population. The spatial distribution showed strong autocorrelation, with a global Moran's I coefficient of 0.272 (P-value <0.001). Five statistically significant clusters were identified by space-time scan statistics using a discrete Poisson model. These identified clusters overlapped in time and had longer durations with a relatively high risk of cholera in the study areas.

Conclusion

The identification of high-risk clusters specific to rural settings forms the basis for rapid public health emergency response and resource allocation by prioritizing the significantly high-risk clusters to control and eventually eliminate cholera. There is room to improve the public health response to cholera outbreaks in the study settings.

Can Wastewater Surveillance Enhance Genomic Tracking of Climate-Driven Pathogens?

Climate change heightens the threat of infectious diseases in Europe, necessitating innovative surveillance methods. Based on 390 scientific papers, for the first time, this review associates climate-related pathogens, data related to their presence in wastewater, and associated available genomic detection methods. This deep analysis reveals a wide range of pathogens that can be tracked through methods such as quantitative and digital PCR, as well as genomic pathogen enrichment in combination with sequencing and metagenomics. Nevertheless, significant gaps remain in the development of methods, particularly for vector-borne pathogens, and in their general harmonization relating to performance criteria. By offering an overview of recent advancements while identifying critical gaps, we advocate for collaborative research and validation to integrate detection techniques into surveillance frameworks. This will enhance public health resilience against emerging infectious diseases driven by climate change.

Recent developments in isothermal amplification technology for rapid detection of SARS-CoV-2

Coronavirus disease 2019 (COVID-19), an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread globally, posing a significant threat to human health. Rapid and accurate detection of infectious disease pathogens is of crucial practical significance for early screening, timely intervention, and outbreak prevention. However, conventional diagnostic methods are increasingly unable to meet clinical demands. Recently developed isothermal analysis methods offer mild reaction conditions and reduce dependence on specialized instruments. These convenient, fast, and reliable methods show great promise for diagnosing infectious pathogens, especially for on-site detection in areas without laboratories or with limited resources. Among them, loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA), which integrate various widely used detection techniques, stand out as rapidly advancing and relatively mature isothermal nucleic acid amplification technologies. This review outlines several representative isothermal amplification technologies and associated detection methods. We summarize the latest advancements in LAMP and RPA technologies for the rapid detection of SARS-CoV-2 and discuss the future prospects of isothermal amplification in diversified testing.

Geographic disparities impacting oral vaccine performance: Observations and future directions

Oral vaccines have several advantages compared with parenteral administration: they can be relatively cheap to produce in high quantities, easier to administer, and induce intestinal mucosal immunity that can protect against infection. These characteristics have led to successful use of oral vaccines against rotavirus, polio, and cholera. Unfortunately, oral vaccines for all three diseases have demonstrated lower performance in the highest-burden settings where they are most needed. Rotavirus vaccines are estimated to have >85% effectiveness against hospitalization in children <12 months in countries with low child mortality, but only ~65% effectiveness in countries with high child mortality. Similarly, oral polio vaccines have lower immunogenicity in developing country settings compared with high-resource settings. Data are more limited for oral cholera vaccines, but suggest lower titers among children compared with adults, and, for some vaccines, lower efficacy in endemic settings compared with non-endemic settings. These disparities are likely multifactorial, and available evidence suggests a role for maternal factors (e.g. transplacental antibodies, breastmilk), host factors (e.g. genetic polymorphisms-with the best evidence for rotavirus-or previous infection), and environmental factors (e.g. gut microbiome, co-infections). Overall, these data highlight the rather ambiguous and often contradictory nature of evidence on factors affecting oral vaccine response, cautioning against broad extrapolation of outcomes based on one population or one vaccine type. Meaningful impact on performance of oral vaccines will likely only be possible with a suite of interventions, given the complex and multifactorial nature of the problem, and the degree to which contributing factors are intertwined.

Water pollution, cholera, and the role of probiotics: a comprehensive review in relation to public health in Bangladesh

Cholera, a disease caused by Vibrio cholerae, remains a pervasive public health threat, particularly in regions with inadequate water sanitation and hygiene infrastructure, such as Bangladesh. This review explores the complex interplay between water pollution and cholera transmission in Bangladesh, highlighting how contaminated water bodies serve as reservoirs for V. cholerae. A key focus is the potential role of probiotics as a novel intervention approach for cholera prevention and management. Probiotics are promising as an adjunctive approach to existing therapies as they can enhance gut barrier function, induce competitive exclusion of pathogens, and modulate host immune responses. Recent probiotic advancements include engineering strains that disrupt V. cholerae biofilms and inhibit their virulence. Integrating probiotics with traditional cholera control measures could significantly enhance their effectiveness and provide a multifaceted approach to combating this persistent disease. This review aims to shed light on the potential of probiotics in revolutionizing cholera management and to offer insights into their application as both preventive and therapeutic tools in the fight against this enduring public health challenge.

The role of morphological adaptability in Vibrio cholerae's motility

Vibrio cholerae, the causative agent of cholera, displays remarkable adaptability to diverse environmental conditions through morphological changes that enhance its pathogenicity and influence the global epidemiology of the disease. This study examines the motility differences between filamentous and comma-shaped forms of the V. cholerae O1 strain under various viscosity conditions. Utilizing the El Tor strain, we induced filamentous transformation and conducted a comparative analysis with the canonical comma-shaped morphology. Our methodology involved assessing motility patterns, swimming speeds, rotation rates, kinematics, and reversal frequencies using dark-field microscopy and high-speed imaging techniques. The results show that filamentous V. cholerae cells retain enhanced motility in viscous environments, indicating an evolutionary adaptation for survival in varied habitats, particularly the human gastrointestinal tract. Filamentous forms exhibited increased reversal behavior at mucin interfaces, suggesting an advantage in penetrating the mucus layer. Furthermore, the presence of filamentous cells in bile-supplemented medium underscores their relevance in natural infection scenarios.

IMPORTANCE

This study highlights the enhanced motility of filamentous Vibrio cholerae in viscous environments, an adaptation that may provide a survival advantage in the human gastrointestinal tract. By demonstrating increased reversal behavior at mucin interfaces, filamentous V. cholerae cells exhibit a superior ability to penetrate the mucus layer, which is crucial for effective colonization and infection. Filamentous cells in bile-supplemented media further underscores their potential role in disease pathogenesis. These findings offer critical insights into the morphological flexibility of V. cholerae and its potential implications for infection dynamics, paving the way for more effective strategies in managing and preventing cholera outbreaks.

Liver abscesses secondary to a non-O1/non-O139 Vibrio cholerae bacteremia acquired in a non-coastal area: a case report

Non-O1/non-O139 Vibrio cholerae (NOVC) strains are a distinct group of Vibrio cholerae that do not cause epidemic cholera. NOVC infections usually cause mild forms of gastroenteritis, and rarely severe (extra)intestinal infections, mostly affecting immunocompromised patients. Here, we describe the clinical course of a patient with NOVC bacteremia causing multiple liver abscesses, after drinking from a freshwater well in a non-coastal area. This case highlights the potential of a V. cholerae strain, that is phylogenetically distinct from the current pandemic cholera strain, to cause severe extra-intestinal infections, including liver abscesses.

Development of Recombinant Antibodies and Its Application in Immunomagnetic Separation-Based Rapid Detection of Vibrio cholerae in Aquatic Environments

Cholera caused by Vibrio cholerae remains a major public health concern in many countries. The greatest obstacle to detection of V. cholerae contamination in drinking water or aquatic environments mainly relates to sample preparation steps, especially the enrichment step. In this study, immunomagnetic separation methods were developed based on sequence-defined recombinant antibodies (rAbs) against V. cholerae, then used for the specific and efficient enrichment of V. cholerae in water samples. Using the variable region genes of the anti-V. cholerae monoclonal antibodies (mAbs) 5F2, the full-length IgG rAbs (R5F2) were produced using mammalian human embryonic kidney 293T cells. Two antibodies, 5F2 and R5F2, were used to prepare immunomagnetic beads (IMBs), and their capture efficiencies (CEs) were evaluated. The results showed that 0.4 mg of 5F2-IMBs and R5F2-IMBs exhibited good CEs (96.0% and 75.9%, respectively) against V. cholerae within 40 min. The IMBs could still effectively capture V. cholerae in large-volume reaction systems (5 ml to 25 ml). The CEs of 5F2-IMBs and R5F2-IMBs ranged from 90.2% to 70.7% and 65.1% to 44.2%, respectively. Furthermore, 5F2-IMBs and R5F2-IMBs did not show significant cross-reactivity with other bacteria and exhibited high specificity. When R5F2-IMS was used in combination with quantitative real-time PCR, the detection limit was approximately 5 colony-forming units/25 ml after enrichment for 4 h. Our results suggest that the rAbs produced herein could provide useful alternatives to traditional hybridoma-based antibodies for accurate detection of V. cholerae in food safety and environmental monitoring.

Vibrio cholerae virulence is blocked by chitosan oligosaccharide-mediated inhibition of ChsR activity

Vibrio cholerae causes cholera, an important cause of death worldwide. A fuller understanding of how virulence is regulated offers the potential for developing virulence inhibitors, regarded as efficient therapeutic alternatives for cholera treatment. Here we show using competitive infections of wild-type and mutant bacteria that the regulator of chitosan utilization, ChsR, increases V. cholerae virulence in vivo. Mechanistically, RNA sequencing, chromatin immunoprecipitation with sequencing and molecular biology approaches revealed that ChsR directly upregulated the expression of the virulence regulator, TcpP, which promoted expression of the cholera toxin and the toxin co-regulated pilus, in response to low O2 levels in the small intestine. We also found that chitosan degradation products inhibit the ChsR-tcpP promoter interaction. Consistently, administration of chitosan oligosaccharide, particularly when delivered via sodium alginate microsphere carriers, reduced V. cholerae intestinal colonization and disease severity in mice by blocking the chsR-mediated pathway. These data reveal the potential of chitosan oligosaccharide as supplemental therapy for cholera treatment and prevention.

Wastewater-based surveillance of Vibrio cholerae: Molecular insights on biofilm regulatory diguanylate cyclases, virulence factors and antibiotic resistance patterns

Vibrio cholerae is an inherent inhabitant of aquatic ecosystems. The Indian state of West Bengal, especially the Gangetic delta region is the highest cholera affected region and is considered as the hub of Asiatic cholera. V. cholerae were isolated from publicly accessible wastewater of Midnapore, West Bengal, India. Serotyping determined all isolates to be of non-O1/non-O139 serogroups. Moderate biofilm-forming abilities were noticed in most of the isolates (74.7 %) while, high biofilm formation was recorded for only 6.3 % isolates and 19 % of isolates exhibited low/non-biofilm-forming abilities. PCR-based screening of crucial diguanylate cyclases (DGCs) involved in cyclic-di-GMP-mediated biofilm signaling was performed. cdgH and cdgM were the most abundant DGCs among 93.7 % and 91.5 % of isolates, respectively. Other important DGCs, i.e., cdgK, cdgA, cdgL, and vpvC were present in 84 %, 75.5 %, 72 % and 68 % of isolates, respectively. Besides, the non-O1/non-O139 isolates were screened for the occurrence of virulence factor encoding genes. Moreover, among these non-O1/non-O139 isolates, two strains (3.17 %) harbored both ctxA and ctxB genes, which encode the cholera toxin associated with epidemic cholera. ompU was the most prevalent virulence factor, present in 24.8 % of isolates. Other virulence factors like, zot and st were found in 4.7 % and 9.5 % of isolates. Genes encoding tcp and ace were found to be PCR-negative for the isolates. Additionally, crucial virulence factor regulators, toxT, toxR and hapR were found to be PCR-positive in all the isolates. Antibiotic resistance patterns displayed further vulnerabilities with decreased sensitivity towards commonly used antibiotics with multiple antibiotic resistance index ranging between 0.37 and 0.62. The presence of cholera toxin-encoding multi-drug resistant (MDR) V. cholerae strains in environmental settings is alarming. High occurrence of DGCs are considered to encourage further investigations to use them as alternative therapeutic targets against MDR cholera pathogen due to their unique presence in bacterial systems.

Detection of foodborne pathogens in contaminated food using nanomaterial-based electrochemical biosensors

Foodborne pathogens are a grave concern for the for food, medical, environmental, and economic sectors. Their ease of transmission and resistance to treatments, such as antimicrobial agents, make them an important challenge. Food tainted with these pathogens is swiftly rejected, and if ingested, can result in severe illnesses and even fatalities. This review provides and overview of the current status of various pathogens and their metabolites transmitted through food. Despite a plethora of studies on treatments to eradicate and inhibit these pathogens, their indiscriminate use can compromise the sensory properties of food and lead to contamination. Therefore, the study of detection methods such as electrochemical biosensors has been proposed, which are devices with advantages such as simplicity, fast response, and sensitivity. However, these biosensors may also present some limitations. In this regard, it has been reported that nanomaterials with high conductivity, surface-to-volume ratio, and robustness have been observed to improve the detection of foodborne pathogens or their metabolites. Therefore, in this work, we analyze the detection of pathogens transmitted through food and their metabolites using electrochemical biosensors based on nanomaterials.

Spotlight on the epidemiology and antimicrobial susceptibility profiles of Vibrio species in the MENA region, 2000-2023

Recent cholera outbreaks in many countries in the Middle East and North Africa (MENA) region have raised public health concerns and focused attention on the genus Vibrio. However, the epidemiology of Vibrio species in humans, water, and seafood is often anecdotal in this region. In this review, we screened the literature and provided a comprehensive assessment of the distribution and antibiotic resistance properties of Vibrio species in different clinical and environmental samples in the region. This review will contribute to understanding closely the real burden of Vibrio species and the spread of antibiotic-resistant strains in the MENA region. The overall objective is to engage epidemiologists, sanitarians and public health stakeholders to address this problem under the One-health ethos.

Multiple endemic equilibria in an environmentally-transmitted disease with three disease stages

We construct, analyze and interpret a mathematical model for an environmental transmitted disease characterized for the existence of three disease stages: acute, severe and asymptomatic. Besides, we consider that severe and asymptomatic cases may present relapse between them. Transmission dynamics driven by the contact rates only occurs when a parameter R∗>1, as normally occur in directly-transmitted or vector-transmitted diseases, but it will not adequately correspond to a basic reproductive number as it depends on environmental parameters. In this case, the forward transcritical bifurcation that exists for R∗<1, becomes a backward bifurcation, producing multiple steady-states, a hysteresis effect and dependence on initial conditions. A threshold parameter for an epidemic outbreak, independent of R∗ is only the ratio of the external contamination inflow shedding rate to the environmental clearance rate. R∗ describes the strength of the transmission to infectious classes other than the I-(acute) type infections. The epidemic outbreak conditions and the structure of R∗ appearing in this model are both responsible for the existence of endemic states.

Towards a Comprehensive Definition of Pandemics and Strategies for Prevention: A Historical Review and Future Perspectives

The lack of a universally accepted definition of a pandemic hinders a comprehensive understanding of and effective response to these global health crises. Current definitions often lack quantitative criteria, rendering them vague and limiting their utility. Here, we propose a refined definition that considers the likelihood of susceptible individuals contracting an infectious disease that culminates in widespread global transmission, increased morbidity and mortality, and profound societal, economic, and political consequences. Applying this definition retrospectively, we identify 22 pandemics that occurred between 165 and 2024 AD and were caused by a variety of diseases, including smallpox (Antonine and American), plague (Justinian, Black Death, and Third Plague), cholera (seven pandemics), influenza (two Russian, Spanish, Asian, Hong Kong, and swine), AIDS, and coronaviruses (SARS, MERS, and COVID-19). This work presents a comprehensive analysis of past pandemics caused by both emerging and re-emerging pathogens, along with their epidemiological characteristics, societal impact, and evolution of public health responses. We also highlight the need for proactive measures to reduce the risk of future pandemics. These strategies include prioritizing surveillance of emerging zoonotic pathogens, conserving biodiversity to counter wildlife trafficking, and minimizing the potential for zoonotic spillover events. In addition, interventions such as promoting alternative protein sources, enforcing the closure of live animal markets in biodiversity-rich regions, and fostering global collaboration among diverse stakeholders are critical to preventing future pandemics. Crucially, improving wildlife surveillance systems will require the concerted efforts of local, national and international entities, including laboratories, field researchers, wildlife conservationists, government agencies and other stakeholders. By fostering collaborative networks and establishing robust biorepositories, we can strengthen our collective capacity to detect, monitor, and mitigate the emergence and transmission of zoonotic pathogens.

Prevalence and antimicrobial susceptibility pattern of Vibrio cholerae isolates from cholera outbreak sites in Ethiopia

BACKGROUND

Cholera is an acute infectious disease caused by ingestion of contaminated food or water with Vibrio cholerae. Cholera remains a global threat to public health and an indicator of inequity and lack of social development. The aim of this study was to assess the prevalence and antimicrobial susceptibility pattern of V. cholerae from cholera outbreak sites in Ethiopia.

METHODS

Across-sectional study was conducted from May 2022 to October 2023 across different regions in Ethiopia: Oromia National Regional State, Amhara National Regional State and Addis Ababa City Administration. A total of 415 fecal samples were collected from the three regions. Two milliliter fecal samples were collected from each study participants. The collected samples were cultured on Blood Agar, MacConkey Agar and Thiosulfate Citrate Bile Salt Sucrose Agar. A series of biochemical tests Oxidase test, String test, Motility, Indole, Citrate, Gas production, H2S production, Urease test were used to identify V. cholerae species. Both polyvalent and monovalent antisera were used for agglutination tests to identify and differentiate V. cholerae serogroup and serotypes. In addition, Kirby-Bauer Disk diffusion antibiotic susceptibility test method was done. Data were registered in epi-enfo version 7 and analyzed by Statistical Package for Social Science version 25. Descriptive statistics were used to determine the prevalence of Vibrio cholerae. Logistic regression model was fitted and p-value < 0.05 was considered as statically significant.

RESULTS

The prevalence of V. cholerae in the fecal samples was 30.1%. Majority of the isolates were from Oromia National Regional State 43.2% (n = 54) followed by Amhara National Regional State 31.2% (n = 39) and Addis Ababa City Administration 25.6% (n = 32). Most of the V. cholerae isolates were O1 serogroups 90.4% (n = 113) and Ogawa serotypes 86.4% (n = 108). Majority of the isolates were susceptible to ciprofloxacin 100% (n = 125), tetracycline 72% (n = 90) and gentamycin 68% (n = 85). More than half of the isolates were resistant to trimethoprim-sulfamethoxazole 62.4% (n = 78) and ampicillin 56.8% (n = 71). In this study, participants unable to read and write were about four times more at risk for V. cholerae infection (AOR: 3.8, 95% CI: 1.07-13.33). In addition, consumption of river water were about three times more at risk for V. cholerae infection (AOR: 2.8, 95% CI: 1.08-7.08).

CONCLUSION

our study revealed a high prevalence of V. cholerae from fecal samples. The predominant serogroups and serotypes were O1 and Ogawa, respectively. Fortunately, the isolates showed susceptible to most tested antibiotics. Drinking water from river were the identified associated risk factor for V. cholerae infection. Protecting the community from drinking of river water and provision of safe and treated water could reduce cholera outbreaks in the study areas.

Tailored multivalent peptide targeting the B-subunit pentamer of cholera toxin inhibits its intestinal toxicity by inducing aberrant transport of the toxin in cells

Cholera toxin (Ctx) is a major virulence factor produced by Vibrio cholerae that can cause gastrointestinal diseases, including severe watery diarrhea and dehydration, in humans. Ctx binds to target cells through multivalent interactions between its B-subunit pentamer and the receptor ganglioside GM1 present on the cell surface. Here, we identified a series of tetravalent peptides that specifically bind to the receptor-binding region of the B-subunit pentamer using affinity-based screening of multivalent random-peptide libraries. These tetravalent peptides efficiently inhibited not only the cell-elongation phenotype but also the elevated cAMP levels, both of which are induced by Ctx treatment in CHO cells or a human colon carcinoma cell line (Caco-2 cells), respectively. Importantly, one of these peptides, NRR-tet, which was highly efficient in these two activities, markedly inhibited fluid accumulation in the mouse ileum caused by the direct injection of Ctx. In consistent, NRR-tet reduced the extensive Ctx-induced damage of the intestinal villi. After NRR-tet bound to Ctx, the complex was incorporated into the cultured epithelial cells and accumulated in the recycling endosome, affecting the retrograde transport of Ctx from the endosome to the Golgi, which is an essential process for Ctx to exert its toxicity in cells. Thus, NRR-tet may be a novel type of therapeutic agent against cholera, which induces the aberrant transport of Ctx in the intestinal epithelial cells, detoxifying the toxin.

Evaluation of humoral and cellular immune responses against Vibrio cholerae using oral immunization by multi-epitope-phage-based vaccine

INTRODUCTION

Cholera is a severe gastrointestinal disease that manifests with rapid onset of diarrhea, vomiting, and high mortality rates. Due to its widespread occurrence in impoverished communities with poor water sanitation, there is an urgent demand for a cost-effective and highly efficient vaccine. Multi-epitope vaccines containing dominant immunological epitopes and adjuvant compounds have demonstrated potential in boosting the immune response.

MATERIAL AND METHODS

B and T epitopes of OMPU, OMPW, TCPA, CTXA, and CTXB proteins were predicted using bioinformatics methods. Subsequently, highly antigenic multi-epitopes that are non-allergenic and non-toxic were synthesized. These multi-epitopes were then cloned into the pCOMB phagemid. A plasmid M13KO7ΔpIII containing all helper phage proteins except pIII was created to produce the recombinant phage. Female Balb/c mice were divided into three groups and immunized accordingly. The mice received the helper phage, recombinant phage or PBS via gavage feeding thrice within two weeks. Serum samples were collected before and after immunization for the ELISA test as well as evaluating immune system induction through ELISpot testing of spleen lymphocytes.

RESULTS

The titer of the recombinant phage was determined to be 1011 PFU/ml. The presence of the recombinant phage was confirmed through differences in optical density between sample and control groups in the ELISA phage technique, as well as by observing transduction activity, which demonstrated successful production of a recombinant phage displaying the Vibrio multi-epitope on M13 phage pIII. ELISA results revealed significant differences in phage antibodies before and after inoculation, particularly notable in the negative control mice. Mice treated with multi-epitope phages exhibited antibodies against Vibrio cholerae lysate. Additionally, ELISpot results indicated activation of cellular immunity in mice receiving both Vibrio and helper phage.

CONCLUSION

This study emphasizes the potential of multi-epitope on phage to enhance both cellular and humoral immunity in mice, demonstrating how phages can be used as adjuvants to stimulate mucosal immunity and act as promising candidates for oral vaccination.

Thiol-Based Modification of MarR Protein VnrR Regulates Resistance Toward Nitrofuran in Vibrio cholerae By Promoting the Expression of a Novel Nitroreductase VnrA and of NO-Detoxifying Enzyme HmpA

Aims: Epidemiological investigations have indicated low resistance toward nitrofuran in clinical isolates, suggesting its potential application in the treatment of multidrug-resistant bacteria. Therefore, it is valuable to explore the mechanism of bacterial resistance to nitrofuran. Results: Through phenotypic screening of ten multiple antibiotic resistance regulator (MarR) proteins in Vibrio cholerae, we discovered that the regulator VnrR (VCA1058) plays a crucial role in defending against nitrofuran, specifically furazolidone (FZ). Our findings demonstrate that VnrR responds to FZ metabolites, such as hydroxylamine, methylglyoxal, hydrogen peroxide (H2O2), β-hydroxyethylhydrazine. Notably, VnrR exhibits reversible responses to the addition of H2O2 through three cysteine residues (Cys180, Cys223, Cys247), leading to the derepression of its upstream gene, vnrA (vca1057). Gene vnrA encodes a novel nitroreductase, which directly contributes to the degradation of FZ. Our study reveals that V. cholerae metabolizes FZ via the vnrR-vnrA system and achieves resistance to FZ with the assistance of the classical reactive oxygen/nitrogen species scavenging pathway. Innovation and Conclusion: This study represents a significant advancement in understanding the antibiotic resistance mechanisms of V. cholerae and other pathogens. Our findings demonstrate that the MarR family regulator, VnrR, responds to the FZ metabolite H2O2, facilitating the degradation and detoxification of this antibiotic in a thiol-dependent manner. These insights not only enrich our knowledge of antibiotic resistance but also provide new perspectives for the control and prevention of multidrug-resistant bacteria.

Cholera rages in Africa and the Middle East: A narrative review on challenges and solutions

Background and Aim

Cholera is a life-threatening infectious disease that is still one of the most common acute watery diarrheal diseases in the world today. Acute diarrhea and severe dehydration brought on by cholera can cause hypovolemic shock, which can be fatal in minutes. Without competent clinical therapy, the rate of case fatality surpasses 50%. The purpose of this review was to highlight cholera challenges in Africa and the Middle East and explain the reasons for why this region is currently a fertile environment for cholera. We investigated cholera serology, epidemiology, and the geographical distribution of cholera in Africa and the Middle East in 2022 and 2023. We reviewed detection methods, such as rapid diagnostic tests (RDTs), and treatments, such as antibiotics and phage therapy. Finally, this review explored oral cholera vaccines (OCVs), and the vaccine shortage crisis.

Methods

We carried out a systematic search in multiple databases, including PubMed, Web of Science, Google Scholar, Scopus, MEDLINE, and Embase, for studies on cholera using the following keywords: ((Cholera) OR (Vibrio cholera) and (Coronavirus) OR (COVID-19) OR (SARS-CoV2) OR (The Middle East) OR (Africa)).

Results and Conclusions

Cholera outbreaks have increased dramatically, mainly in Africa and many Middle Eastern countries. The COVID-19 pandemic has reduced the attention devoted to cholera and disrupted diagnosis and treatment services, as well as vaccination initiatives. Most of the cholera cases in Africa and the Middle East were reported in Malawi and Syria, respectively, in 2022. RDTs are effective in the early detection of cholera epidemics, especially with limited advanced resources, which is the case in much of Africa. By offering both direct and indirect protection, expanding the use of OCV will significantly reduce the burden of current cholera outbreaks in Africa and the Middle East.

Cholera outbreaks among children in sub-Saharan Africa

PURPOSE OF REVIEW

We review current knowledge on the burden, impact and prevention of cholera among children who bear the brunt of cholera outbreaks in sub-Saharan Africa.

RECENT FINDINGS

Several studies have shown that recent outbreaks of cholera among African children are related to minimal progress in basic sanitation and infrastructural development. Poor hygiene practices such as open defecation and indiscriminate disposal of feces are still common in many parts of Africa.

SUMMARY

Cholera case fatality rates in sub-Saharan Africa remain unacceptably high. Children are disproportionately affected and bear the brunt of the disease. Controlling outbreaks of cholera among African children will require a synchronous implementation of the five levels of disease prevention.

Sporadic regional re-emergent cholera: a 19th century problem in the 21st century

Cholera, caused by Vibrio cholerae, is a severe diarrheal disease that necessitates prompt diagnosis and effective treatment. This review comprehensively examines various diagnostic methods, from traditional microscopy and culture to advanced nucleic acid testing like polymerase spiral reaction and rapid diagnostic tests, highlighting their advantages and limitations. Additionally, we explore evolving treatment strategies, with a focus on the challenges posed by antibiotic resistance due to the activation of the SOS response pathway in V. cholerae. We discuss promising alternative treatments, including low-pressure plasma sterilization, bacteriophages, and selenium nanoparticles. The paper emphasizes the importance of multidisciplinary approaches combining novel diagnostics and treatments in managing and preventing cholera, a persistent global health challenge. The current re-emergent 7th pandemic of cholera commenced in 1961 and shows no signs of abeyance. This is probably due to the changing genetic profile of V. cholerae concerning bacterial pathogenic toxins. Given this factor, we argue that the disease is effectively re-emergent, particularly in Eastern Mediterranean countries such as Lebanon, Syria, etc. This review considers the history of the current pandemic, the genetics of the causal agent, and current treatment regimes. In conclusion, cholera remains a significant global health challenge that requires prompt diagnosis and effective treatment. Understanding the history, genetics, and current treatments is crucial in effectively addressing this persistent and re-emergent disease.

Ophthalmic implications of biological threat agents according to the chemical, biological, radiological, nuclear, and explosives framework

As technology continues to evolve, the possibility for a wide range of dangers to people, organizations, and countries escalate globally. The United States federal government classifies types of threats with the capability of inflicting mass casualties and societal disruption as Chemical, Biological, Radiological, Nuclear, and Energetics/Explosives (CBRNE). Such incidents encompass accidental and intentional events ranging from weapons of mass destruction and bioterrorism to fires or spills involving hazardous or radiologic material. All of these have the capacity to inflict death or severe physical, neurological, and/or sensorial disabilities if injuries are not diagnosed and treated in a timely manner. Ophthalmic injury can provide important insight into understanding and treating patients impacted by CBRNE agents; however, improper ophthalmic management can result in suboptimal patient outcomes. This review specifically addresses the biological agents the Center for Disease Control and Prevention (CDC) deems to have the greatest capacity for bioterrorism. CBRNE biological agents, encompassing pathogens and organic toxins, are further subdivided into categories A, B, and C according to their national security threat level. In our compendium of these biological agents, we address their respective CDC category, systemic and ophthalmic manifestations, route of transmission and personal protective equipment considerations as well as pertinent vaccination and treatment guidelines.

Food safety-related practices among residents aged 18-75 years during the COVID-19 pandemic: a cross-sectional study in Southwest China

BACKGROUND

Good food safety practices are essential to minimizing foodborne diseases. The present study explored the food safety-related practices of residents during the COVID-19 pandemic in Southwest China and identified the impacting factors.

METHODS

Residents aged 18-75 years from Guizhou, Yunnan, Sichuan, and Chongqing, China, were included in our study. The convenience sampling method was used to select participants, and face-to-face surveys were conducted in households and communities to collect data. Descriptive statistics including sociodemographic characteristics of respondents and weighted percentages were obtained and the log-binomial regression was used to evaluate the influencing factors associated with food safety-related practices.

RESULTS

Overall, 7,848 respondents were involved, with 97.5% efficacy. Disparities in food safety-related practices were observed between males and females, with the former performing poorer practices than the latter (70.5% vs. 68.0%, respectively). Notably, paying attention to nutrition labels when shopping for prepackaged foods was the worst practice. Age, ethnicity, region, occupation, education level, and income were identified as significant determinants of food safety-related practices. Moreover, in comparison to males, females were more likely to acquire pertinent knowledge from diverse sources, including social media, family members/ friends, books/ newspapers/ magazines, experts, and food sales staff (p < 0.05).

CONCLUSIONS

Males performed inferior food safety-related practices than females during the COVID-19 pandemic in Southwest China. It is suggested that future food safety education programs should incorporate diverse targeted approaches, with emphasis on males. The role of mainstream media in promoting food safety practices should be expanded and prioritized in the forthcoming initiatives.

An Interesting Case of Asymptomatic Cholera in the Setting of Large Bowel Obstruction

Vibrio cholerae is the culprit behind many endemics globally. Classically characterized by profuse diarrhea with a "rice water" description, cholera can be fatal if not treated promptly. However, infected individuals can present with little to no symptoms. These individuals allow for a carrier state and play a large part in the survival of an endemic. Asymptomatic patients can present in areas where Cholera is not endemic. Herein, we present an atypical case of vibrio chloerae infection without diarrhea in the setting of large bowel obstruction secondary to colon cancer. We aim to highlight the unusual presentation of a cholera infection.

The health of mankind and the health of the planet in a historical-ethical perspective: an inseparable relationship and a single destiny

Recent years have seen increasingly severe natural disasters, the consequences of which have been catastrophic. Clearly, our global environment is undergoing major changes. The climate is becoming deranged and pollution on a global scale afflicts air, water, and land. We are faced with an unprecedented shortage of cultivable land and fresh water for drinking, irrigation, and livestock farming, while our marine systems are breaking down. These environmental changes have a very high anthropogenic component; they are induced by human activities that are potentially dangerous for both the environment and human life. Moreover, not only do they have an enormous impact on the environments in which we live and on our way of life, they also have harmful effects on our health. Indeed, we must understand that our body - as Hippocrates explained long ago - is a system that constantly interacts with the surrounding environment.

Pharmacological Management of Cholera: A Century of Expert Opinions in Cecil Textbook of Medicine

BACKGROUND

Cholera is a potentially lethal diarrheal disease produced by Vibrio cholerae serotypes O1 El Tor and O139. Known since antiquity, the condition causes epidemics in many areas, particularly in Asia, Africa, and South America. Left untreated, the mortality may reach 50%. The crucial therapeutic intervention is intravenous or oral rehydration and correction of acidosis, dyselectrolytemia, and renal impairment. Antibiotic use represents the main pharmacological intervention.

STUDY QUESTION

What are the milestones of the antibiotics use recommended by experts for the pharmacological management of cholera in the past century?

STUDY DESIGN

To determine the changes in the experts' approach to the management of cholera and particularly the use of antibiotics as presented in a widely used textbook in the United States.

DATA SOURCES

The chapters describing the management of cholera in the 26 editions of Cecil Textbook of Medicine published from 1927 through 2020.

RESULTS

Sulfonamides were recommended in 1947, followed by the introduction of tetracyclines, chloramphenicol, and furazolidone in 1955. The options were restricted in 2000 to doxycycline. In the past decade, patients infected with strains known to have a degree a resistance to tetracyclines were treated with azithromycin or ciprofloxacin. Antibiotic use decreases the volume of stool and the duration of diarrhea but has not been considered lifesaving. Drugs with antimotility, antiemetic, or antisecretory properties are not useful.

CONCLUSIONS

The utility of antibiotic use in cholera has been endorsed by experts, but only as an adjunct to rapid and complete fluid and electrolyte replacement.

Acute gastroenteritis due to Vibrio cholerae biovar albensis infection: A case report

Vibrio cholerae represents diverse species and includes pathogenic and non-pathogenic variants. Particularly serogroups O1 and O139 are related to cholera epidemics, while non-O1/O139 serogroups (NOVC) in general are non-pathogenic or asymptomatic colonizers in humans, but also can cause different diseases. Vibrio albensis, a non-O1/non-O-139 serogroup, is rarely implicated in human infections. Only a few cases of human pathology related to this species are described in the literature. We present the menagement of V. albensis gastroenteritis in a a 47-year-old woman and discuss clinical presentation, diagnosis and treatement.

VP3 Phage Combined with High Salt Promotes the Lysis of Biofilm-Associated Vibrio cholerae

Cholera, caused by pathogenic Vibrio cholerae, poses a significant public health risk through water and food transmission. Biofilm-associated V. cholerae plays a crucial role in seasonal cholera outbreaks as both a reservoir in aquatic environments and a direct source of human infection. Although VP3, a lytic phage, shows promise in eliminating planktonic V. cholerae from the aquatic environment, its effectiveness against biofilm-associated V. cholerae is limited. To address this limitation, our proposed approach aims to enhance the efficacy of VP3 in eliminating biofilm-associated V. cholerae by augmenting the availability of phage receptors on the surface of Vibrio cholerae. TolC is a receptor of VP3 and a salt efflux pump present in many bacteria. In this study, we employed NaCl as an enhancer to stimulate TolC expression and observed a significant enhancement of TolC expression in both planktonic and biofilm cells of V. cholerae. This enhancement led to improved adsorption of VP3. Importantly, our findings provide strong evidence that high salt concentrations combined with VP3 significantly improve the elimination of biofilm-associated V. cholerae. This approach offers a potential strategy to eliminate biofilm-formation bacteria by enhancing phage-host interaction.

Cholera Infection Risks and Cholera Vaccine Safety in Pregnancy

Introduction

Discuss the impact of cholera infection on pregnant women, fetus, and neonates and review the safety of cholera vaccines in pregnancy.

Methods

This study was carried out as a narrative review during November 2022. A thorough literature review was conducted on the following databases: PubMed, Scopus, SciELO, CINAHL, Web of Science, and ScienceDirect. The following parameters were assessed from the included studies: type of cholera vaccine, cholera symptoms, cholera treatment, effect of cholera on pregnancy, effect of cholera treatment on pregnancy, effect of cholera vaccine on pregnancy, risk factors for fetuses and neonates, and prevention of cholera. The authors independently extracted data from the 24 included studies.

Results

Cholera infection is a serious threat on pregnancy as it could lead to increased stillbirths and neonatal death. Fetal death was shown to occur mainly in the third trimester as most of the pregnant women infected with cholera had spontaneous abortions even after controlling for other confounding variables such as maternal age, dehydration level, and vomiting. Neonatal death was attributed mainly to congenital malformations and low Apgar scores with no improvements. Besides, cholera vaccines have shown to be safe in pregnancy and have proven to lower fetal and neonatal malformations among vaccinated compared to nonvaccinated pregnant women.

Conclusion

This narrative summarizes the different complications due to cholera infection in pregnancy. It also reviews the safety of cholera vaccine administration in pregnant women.

Vibrio cholerae, classification, pathogenesis, immune response, and trends in vaccine development

Vibrio cholerae is the causative agent of cholera, a highly contagious diarrheal disease affecting millions worldwide each year. Cholera is a major public health problem, primarily in countries with poor sanitary conditions and regions affected by natural disasters, where access to safe drinking water is limited. In this narrative review, we aim to summarize the current understanding of the evolution of virulence and pathogenesis of V. cholerae as well as provide an overview of the immune response against this pathogen. We highlight that V. cholerae has a remarkable ability to adapt and evolve, which is a global concern because it increases the risk of cholera outbreaks and the spread of the disease to new regions, making its control even more challenging. Furthermore, we show that this pathogen expresses several virulence factors enabling it to efficiently colonize the human intestine and cause cholera. A cumulative body of work also shows that V. cholerae infection triggers an inflammatory response that influences the development of immune memory against cholera. Lastly, we reviewed the status of licensed cholera vaccines, those undergoing clinical evaluation, and recent progress in developing next-generation vaccines. This review offers a comprehensive view of V. cholerae and identifies knowledge gaps that must be addressed to develop more effective cholera vaccines.

A Molecular and Epidemiological Study of Cholera Outbreak in Sulaymaniyah Province, Iraq, in 2022

Cholera is a disease caused by a Gram-negative bacterium Vibrio cholerae and is among the significant threats to global public health. The disease is mainly spread in the hot months of the year; low sanitation and lack of clean water are the major causes of the disease. In this study, we conducted a molecular and epidemiological study of the recent outbreak in the city of Sulaymaniyah in Iraq. Based on the bacteriological, serological, and molecular identification of the bacterium, it was shown that V. cholerae O1 serotype Ogawa caused the disease. Additionally, the number of positive cholera cases were higher in June compared to July (391 positive cases in June and 23 in July). Moreover, the majority (> 60%) of the cholera cases were recorded among 20-44-year-old people in both months; however, there was no significant difference in the patient genders diagnosed every month. Overall, this is the first report on the recent cholera outbreak in the city of Sulaimaniyah in Iraq.

A snap-shot of a diarrheal epidemic in Dhaka due to enterotoxigenic Escherichia coli and Vibrio cholerae O1 in 2022

Background

Enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae O1 are most common bacterial causes of diarrheal diseases in Bangladesh. This analysis projected distribution of ETEC and V. cholerae O1 among diarrheal patients of icddr,b, Dhaka hospital in two diarrheal peaks of 2022.

Methodology

Under the 2% systematic surveillance system, stool samples collected from diarrheal patients of icddr,b hospital were cultured and diagnostic testing was done for ETEC and V. cholerae O1. Comparison of positive cases was done between first peak (March-April) and second peak (October-November) in 2022.

Results

A total of 2,937 stool specimens were tested of which 12% were ETEC and 20% were V. cholerae O1. About 40% of the severe dehydration cases were infected with V. cholerae O1. Predominant ETEC enterotoxin type was 'LT/ST' (41%). The LT enterotoxin significantly increased from 13% to 28% in the second peak (p = 0.015). The predominant colonization factors (CFs) on ETEC were CS5 + CS6 (23%), followed by CS6 (15%). CF-positive isolates was significantly higher in the second peak (36%) than in the first peak (22%) (p = 0.043). Total 14% cases were co-infected with ETEC and V. cholerae O1. Significant differences in the distribution of enterotoxin types were observed (p = 0.029) among the co-infection cases.

Conclusion

Changing patterns of enterotoxin and CFs observed in ETEC pathogens should be taken into consideration for ETEC vaccine development. Considering cholera and ETEC biannual trends in causing diarrheal epidemics and outbreaks, emphasizes the need for thoughts on combination vaccine strategies for preventing acute watery diarrhea due to the two major bacterial pathogens.