Global climate and infectious disease: the cholera paradigm

Artificial intelligence in bacterial diagnostics and antimicrobial susceptibility testing: Current advances and future prospects

Recently, artificial intelligence (AI) has emerged as a transformative tool, enhancing the speed, accuracy, and scalability of bacterial diagnostics. This review explores the role of AI in revolutionizing bacterial detection and antimicrobial susceptibility testing (AST) by leveraging machine learning models, including Random Forest, Support Vector Machines (SVM), and deep learning architectures such as Convolutional Neural Networks (CNNs) and transformers. The integration of AI into these methods promises to address the current limitations of traditional techniques, offering a path toward more efficient, accessible, and reliable diagnostic solutions. In particular, AI-based approaches have demonstrated significant potential in resource-limited settings by enabling cost-effective and portable diagnostic solutions, reducing dependency on specialized infrastructure, and facilitating remote bacterial detection through smartphone-integrated platforms and telemedicine applications. This review highlights AI's transformative role in automating data analysis, minimizing human error, and delivering real-time diagnostic results, ultimately improving patient outcomes and optimizing healthcare efficiency. In addition, we not only examine the current advances in machine learning and deep learning but also review their applications in plate counting, mass spectrometry, morphology-based and motion-based microscopic detection, holographic microscopy, colorimetric and fluorescence detection, electrochemical sensors, Raman and Surface-Enhanced Raman Spectroscopy (SERS), and Atomic Force Microscopy (AFM) for bacterial diagnostics and AST. Finally, we discuss the future directions and potential advancements in AI-driven bacterial diagnostics.

Assessment of water scarcity as a risk factor for cholera outbreaks

INTRODUCTION

Increasing aridity and incidence of droughts pose a significant threat to human health, primarily in exacerbating water scarcity, and is projected to become more frequent and severe as a result of related environmental changes in many regions globally. Concomitantly, water scarcity will force populations to utilize potentially contaminated water sources, hence increasing exposure to waterborne diseases, notably cholera. Proliferation of Vibrio cholerae, causative agent of cholera, is driven by environmental factors. Notably, temperature and precipitation have been employed in providing predictive awareness of cholera, allowing early warning and mitigation. The impact of droughts on incidence and spread of cholera is less understood.

METHODS

This study aimed to quantify relationships among temperature, precipitation, and droughts as a basis for establishing the connection of environmental parameters and outbreaks of cholera. Thirteen cholera outbreaks between 2003 and 2023 in four African countries (Ethiopia, Kenya, Nigeria, and Senegal) were assessed using odds ratio and k-means clustering analysis.

RESULTS

Cholera outbreaks were 3.07 (95 % CI: [0.95, 9.88]) times more likely when drought conditions (negative precipitation anomalies, positive temperature anomalies, and negative Standardized Precipitation-Evapotranspiration Index) were present, compared to their absence. When excess rainfall was also considered, the odds ratio increased to 3.50 (95 % CI: [1.03, 11.90]). Complementary evidence obtained using k-means clustering analysis supported the conclusion that outbreaks of cholera were common during drought conditions.

CONCLUSIONS

Considering the last few decades with increased severity and frequency of droughts in cholera-impacted regions, climate projections indicate the threat of cholera outbreaks will continue, especially noting increasing reports of cholera globally. Hence, predictive intelligence systems for rapid risk assessment, with respect to climate, drought, and human health, are warranted.

Prevalence of Vibrio cholerae in an Acute Watery Diarrhea Outbreak in Sulaymaniyah City, Iraq

Cholera is a life-threatening diarrheal disease caused by Vibrio cholerae, with recurring outbreaks in Iraq, including the Kurdistan Region. Despite its endemic nature, outbreaks have primarily been reported by the health sector without comprehensive molecular epidemiological investigations. Limited studies have characterized outbreak dynamics, prevalence, and antimicrobial resistance, hindering effective public health interventions. This study aimed to analyze the prevalence, molecular characteristics, and antibiotic resistance of V. cholerae isolates from the 2023 outbreak in Sulaymaniyah, Kurdistan, Iraq. A total of 1200 diarrheic stool samples were collected from Shar Hospital between July and October 2023. Bacterial isolation was performed using microbiological methods and automated VITEK 2 analysis, followed by serological identification (O1 and O139 antisera) and 16S rRNA gene sequencing. Antibiotic susceptibility testing (AST) was conducted to assess resistance patterns. The outbreak prevalence was 0.015%, with the highest infection rate in August (0.009%). The overall infection rate was 28.91% (347/1200), with the most affected age groups being 19-33 years (27.66%) and 34-48 years (26.22%). Infection was more common in females (55.6%) than males (44.4%). Phylogenetic analysis revealed high genetic similarity to the V. cholerae Kuwait1 strain, suggesting potential introduction from southern Iraq, possibly due to an influx of tourists. Furthermore, antibiotic susceptibility testing revealed that all V. cholerae isolates were susceptible to most tested antibiotics; however, complete resistance (100%) was observed against amikacin, amoxicillin, amoxiclav, nalidixic acid, and trimethoprim, with partial resistance (30%) to tetracycline. Cholera remains a major public health concern in Kurdistan, particularly in Sulaymaniyah, due to recurrent outbreaks. Molecular techniques provided crucial insights into outbreak tracking and genetic relatedness, while AST profiling highlighted the urgent need for revised treatment guidelines. Strengthening water sanitation, continuous antimicrobial resistance monitoring, and targeted public health interventions are essential for preventing future outbreaks.

In Vivo Nitrosative Stress-Induced Expression of a Photolyase Promotes Vibrio cholerae Environmental Blue Light Resistance

Bacterial pathogens possess a remarkable capacity to sense and adapt to ever-changing environments. For example, Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, thrives in aquatic ecosystems and human hosts through dynamic survival strategies. In this study, we investigated the role of three photolyases, enzymes that repair DNA damage caused by exposure to UV radiation and blue light, in the environmental survival of V. cholerae. Among these, we identified cry1 as critical for resistance to blue light, as mutations in this gene, but not in the other photolyase genes, rendered V. cholerae susceptible to such stress. Expression of cry1 was induced by blue light and regulated by RpoE and the anti-sigma factor ChrR. We further showed that nitric oxide (NO), a host-derived stressor encountered during infection, also activated cry1 expression. We found that one of the two cysteine residues in ChrR was important for sensing reactive nitrogen species (RNS), thereby modulating cry1 expression. While Cry1 was not required for V. cholerae colonization in animal models, pre-induction of Cry1 by RNS in vivo or in vitro enhanced V. cholerae resistance to blue light. These findings suggest that host-derived NO encountered during infection primes V. cholerae for survival in blue-light-rich aquatic environments, supporting its transition between host and environmental niches.

Scoping review on assessing climate-sensitive health risks

BACKGROUND

Climate change is making the existing health problems worse and also introducing new health problem and therefore calls for a wider evaluation of climate sensitive global diseases. The review sought to assess and collate quantitative and qualitative evidence on the effects of climate change on global health, more specifically, infectious and respiratory diseases, the impacts of extreme weather events as well as the implications for mental health with the view of establishing appropriate sustainable and resilience public health measures and policies.

METHODOLOGY

A scoping review of observational studies carried out between the years 2000 and 2024, synthesized information on climate-sensitive health outcomes: infectious diseases, severe weather events, and mental illnesses. This analysis was based on data from PubMed, Scopus, Web of Science and Cochrane Library, where appropriate, utilizing meta-extraction and Meta-analysis techniques.

RESULTS

A total of 3077 studies were screened, and 96 articles were included for quantitative and qualitative analysis, highlighting the significant health risks posed by climate change. Key areas of concern identified include climate-sensitive infectious diseases, respiratory and cardiovascular conditions, food- and water-borne illnesses, and mental health effects. Rising temperatures and variable rainfall patterns increase the incidence of diseases like malaria (up to 50%) and dengue (8-10% per 1 °C rise). Extreme weather events, such as heatwaves and floods, contribute to a 30% rise in respiratory diseases and a 25% increase in cardiovascular conditions. Food- and water-borne illnesses are more prevalent in regions like Africa (30-40%) due to climate change. Additionally, climate change exacerbates mental health issues, leading to conditions like post-traumatic stress disorder (PTSD), anxiety, and depression.

CONCLUSION AND RECOMMENDATIONS

Climate change amplifies global public health risks, worsening diseases and creating new challenges. To address this, enhance machine learning climate sensitive disease surveillance, strengthen climate resilience health infrastructure, and integrate health into climate adaptation and mitigation strategies, promote sustainable agriculture, improve WASH infrastructure, and foster global collaboration.

Climate change and Vibrio vulnificus dynamics: A blueprint for infectious diseases

Climate change is having increasingly profound effects on human health, notably those associated with the occurrence, distribution, and transmission of infectious diseases. The number of disparate ecological parameters and pathogens affected by climate change are vast and expansive. Disentangling the complex relationship between these variables is critical for the development of effective countermeasures against its effects. The pathogen Vibrio vulnificus, a naturally occurring aquatic bacterium that causes fulminant septicemia, represents a quintessential climate-sensitive organism. In this review, we use V. vulnificus as a model organism to elucidate the intricate network of interactions between climatic factors and pathogens, with the objective of identifying common patterns by which climate change is affecting their disease burden. Recent findings indicate that in regions native to V. vulnificus or related pathogens, climate-driven natural disasters are the chief contributors to their disease outbreaks. Concurrently, climate change is increasing the environmental suitability of areas non-endemic to their diseases, promoting a surge in their natural populations and transmission dynamics, thus elevating the risk of new outbreaks. We highlight potential risk factors and climatic drivers aggravating the threat of V. vulnificus transmission under both scenarios and propose potential measures for mitigating its impact. By defining the mechanisms by which climate change influences V. vulnificus disease burden, we aim to shed light on the transmission dynamics of related disease-causing agents, thereby laying the groundwork for early warning systems and broadly applicable control measures.

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.

Accelerating growth of human coastal populations at the global and continent levels: 2000-2018

Current human population growth along Earth's coasts is on a collision path with anticipated consequences of increasing natural and anthropogenic induced coastal hazards. Using recently-available ambient, dasymetric data, we developed methods to estimate annual continental and global coastal populations from (2000-2018) measured horizontally from the shoreline inward. We found: (1) large concentrations of population in relatively small bands and regions along the coast (~ 2 billion within 50 km and ~ 1 billion within 10 km); (2) higher growth rates of coastal population than inland population (an addition of 463 million within 50 km and 233 million within 10 km); (3) strong influence of distance from the coast to predict population distribution; and (4) that macro population patterns and growth could be expressed and modeled as a power function at continental and global levels. Findings point to emerging macro population patterns along the coast as contributing to increasing anthropogenic effects on Earth systems and increasing human risks associated with sea-level rise, land subsidence, extreme weather, and public health. Reliable data tracking of the magnitude, spatial distribution and change of human populations in the coastal regions is essential for comprehensive coastal monitoring.

High temperatures increase the virulence of Vibrio bacteria towards their coral host and competing bacteria via type VI secretion systems

The bacterial pathogen Vibrio coralliilyticus induces severe coral diseases in warming oceans. A study in PLOS Biology reveals that high temperatures activate 2 type VI secretion systems in V. coralliilyticus, enhancing pathogenicity by deploying toxic effectors against competing bacteria and coral cells.

Hemolysin Coregulated Protein (HCP) from Vibrio Cholerae Interacts with the Host Cell Actin Cytoskeleton

Vibrio cholerae (V. cholerae), the etiological agent of cholera, employs various virulence factors to adapt and thrive within both aquatic and human host environments. Among these factors, the type VI secretion system (T6SS) stands out as one of the crucial determinants of its pathogenicity. Valine glycine repeat protein G1 (VgrG1) and hemolysin coregulated protein (HCP) are considered major effector molecules of T6SS. Previous studies have highlighted that VgrG1 interacts with HCP proteins. Additionally, it has been shown that VgrG1 possesses an actin cross-linking domain (ACD) with actin-binding activity. Interestingly, it was reported that purified HCP protein treatment increased the stress fibers within cells. Therefore, we hypothesize that HCP may interact with host cell actin, potentially playing a role in the cytoskeletal rearrangement during V. cholerae infection. To test this hypothesis, we characterized HCP from the V. cholerae O139 serotype and demonstrated its interaction with actin monomers. In silico analysis and experimental validation revealed the presence of an actin-binding site within HCP. Furthermore, overexpression of HCP resulted in its colocalization with actin stress fibers in host cells. Our findings establish HCP as an effector molecule for potent host cell actin cytoskeleton remodeling during V. cholerae infection, providing new insights into bacterial pathogenicity mechanisms. Understanding the interplay between bacterial effectors and host cell components is crucial for developing targeted therapeutic interventions against cholera and related infectious diseases.

The 2016 Severe Floods and Incidence of Hemorrhagic Fever With Renal Syndrome in the Yangtze River Basin

Importance

Hemorrhagic fever with renal syndrome (HFRS), a neglected zoonotic disease, has received only short-term attention in postflood prevention and control initiatives, possibly because of a lack of evidence regarding the long-term association of flooding with HFRS.

Objectives

To quantify the association between severe floods and long-term incidence of HFRS in the Yangtze River basin and to examine the modifying role of geographical factors in this association.

Design, Setting, and Participants

This cross-sectional study collected data on HFRS cases between July 1, 2013, and June 30, 2019, from 58 cities in 4 provinces (Anhui, Hubei, Hunan, and Jiangxi) in the Yangtze River basin of China, with a breakpoint of flooding in July 2016, generating monthly data. The 3 years after July 2016 were defined as the postflood period, while the 3 years before the breakpoint were defined as the control period. Statistical analysis was performed from October to December 2023.

Exposures

City-level monthly flooding, elevation, ruggedness index, and closest distance from each city to the Yangtze River and its tributaries.

Main Outcomes and Measures

The primary outcomes were the number of city-level monthly HFRS cases and the number of type 1 (spring or summer) and type 2 (autumn or winter) HFRS cases.

Results

A total of 11 745 patients with HFRS were reported during the study period: 5216 patients (mean [SD] age, 47.1 [16.2] years; 3737 men [71.6%]) in the control period and 6529 patients (mean [SD] age, 49.8 [15.8] years; 4672 men [71.6%]) in the postflood period. The pooled effects of interrupted time series analysis indicated a long-term association between flooding and HFRS incidence (odds ratio, 1.38; 95% CI, 1.13-1.68), with type 1 cases being at highest risk (odds ratio, 1.71; 95% CI, 1.40-2.09). The metaregression results indicated that elevation and ruggedness index were negatively associated with the risk of HFRS, while the distance to rivers interacted with these associations.

Conclusions and Relevance

This cross-sectional study of the long-term association between flooding and HFRS incidence, as well as the modification effects of geographical factors, suggests that severe floods were associated with an increased risk of HFRS within 3 years. This study provides evidence for the development of HFRS prevention and control strategies after floods.

Strain variation and anomalous climate synergistically influence cholera pandemics

BACKGROUND

Explanations for the genesis and propagation of cholera pandemics since 1817 have remained elusive. Evolutionary pathogen change is presumed to have been a dominant factor behind the 7th "El Tor" pandemic, but little is known to support this hypothesis for preceding pandemics. The role of anomalous climate in facilitating strain replacements has never been assessed. The question is of relevance to guide the understanding of infectious disease emergence today and in the context of climate change.

METHODOLOGY/PRINCIPAL FINDINGS

We investigate the roles of climate and putative strain variation for the 6th cholera pandemic (1899-1923) using newly assembled historical records for climate variables and cholera deaths in provinces of former British India. We compare this historical pandemic with the 7th (El Tor) one and with the temporary emergence of the O139 strain in Bangladesh and globally. With statistical methods for nonlinear time series analysis, we examine the regional synchrony of outbreaks and associations of the disease with regional temperature and rainfall, and with the El Niño Southern Oscillation (ENSO). To establish future expectations and evaluate climate anomalies accompanying historical strain replacements, climate projections are generated with multi-model climate simulations for different 50-year periods. The 6th cholera pandemic featured the striking synchronisation of cholera outbreaks over Bengal during the El Niño event of 1904-07, following the invasion of the Bombay Presidency with a delay of a few years. Accompanying anomalous weather conditions are similar to those related to ENSO during strain replacements and pandemic expansions into Africa and South America in the late 20th century. Rainfall anomalies of 1904-05 at the beginning of the large cholera anomaly fall in the 99th percentile of simulated changes for the regional climate.

CONCLUSIONS/SIGNIFICANCE

Evolutionary pathogen change can act synergistically with climatic conditions in the emergence and propagation of cholera strains. Increased climate variability and extremes under global warming provide windows of opportunity for emerging pathogens.

Acute gastroenteritis caused by Vibrio cholerae O1 Ogawa serotype in gastric cancer patient in Eastern India: Case report and review of literature

ABSTRACT

Acute gastroenteritis is the most common clinical manifestation of Vibrio cholerae infection. Cases of non-O1 V. cholerae infections in cancer patients have been previously reported in the literature. To our best knowledge, this is a unique case of V. cholerae classical biotype, serovar Ogawa infection in a young female patient with gastric malignancy.

Effect of a Water, Sanitation, and Hygiene Program on Handwashing with a Cleansing Agent among Diarrhea Patients and Attendants in Healthcare Facilities in the Democratic Republic of the Congo: A Randomized Pilot of the PICHA7 Program

Healthcare-acquired infections are a major problem in healthcare facility settings around the world. The Democratic Republic of the Congo (DRC) has over 2 million diarrhea patients hospitalized each year. These healthcare settings become high-risk environments for spreading diarrheal illnesses such as cholera. The objective of the Preventative Intervention for Cholera for 7 Days (PICHA7) program is to develop evidence-based water, sanitation, and hygiene (WASH) interventions to reduce cholera and other severe diarrheal diseases in the DRC. The study objective was to evaluate the effectiveness of PICHA7 program delivery in increasing handwashing with a cleansing agent at stool/vomit- and food-related events in a healthcare facility setting among diarrhea patients and patient attendants. A pilot of the PICHA7 program was conducted among 284 participants in 27 healthcare facilities from March 2020 to November 2021 in urban Bukavu in the South Kivu Province of the DRC. The standard arm received the standard message provided in the DRC to diarrhea patients on the use of oral rehydration solution and a basic WASH message at healthcare facility discharge. The PICHA7 arm received the PICHA7 WASH pictorial module delivered by a health promoter focused on handwashing with a cleansing agent at the bedside of the diarrhea patient in the healthcare facility and provision of a soapy water bottle (water and detergent powder). Within 24 h of intervention delivery, a three-hour structured observation of handwashing practices at stool/vomit- and food-related events (key events) was conducted in healthcare facilities of diarrhea patients and their attendants. Compared to the standard arm, there was significantly more handwashing with a cleansing agent at key events in the PICHA7 arm (40% vs. 15%) (odds ratio: 5.04; (95% confidence interval (CI): 2.01, 12.7)). These findings demonstrate that delivery of the PICHA7 WASH pictorial module and provision of a soapy water bottle to diarrhea patients and their attendants presents a promising approach to increase handwashing with a cleansing agent among this high-risk population in healthcare facilities in the eastern DRC.

Tracking Vibrio: population dynamics and ecology of Vibrio parahaemolyticus and V. vulnificus in an Alabama estuary

Vibrio is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of pathogenic Vibrio spp. (e.g., consuming raw shellfish). High rates of mortality from certain Vibrio spp. infections demonstrate the need for an improved understanding of Vibrio spp. dynamics in estuarine regions. Our study assessed meteorological, hydrographic, and biological correlates of Vibrio parahaemolyticus and V. vulnificus at 10 sites in the Eastern Mississippi Sound System (EMSS) from April to October 2019. During the sampling period, median abundances of V. parahaemolyticus and V. vulnificus were 2.31 log MPN/L and 2.90 log MPN/L, respectively. Vibrio spp. dynamics were largely driven by site-based variation, with sites closest to freshwater inputs having the highest abundances. The E-W wind scalar, which affects Ekman transport, was a novel Vibrio spp. correlate observed. A potential salinity effect on bacterial-particle associations was identified, where V. vulnificus was associated with larger particles in conditions outside of their optimal salinity. Additionally, V. vulnificus abundances were correlated to those of harmful algal species that did not dominate community chlorophyll. Correlates from this study may be used to inform the next iteration of regionally predictive Vibrio models and may lend additional insight to Vibrio spp. ecology in similar systems.

IMPORTANCE

Vibrio spp. are bacteria found in estuaries worldwide; some species can cause illness and infections in humans. Relationships between Vibrio spp. abundance, salinity, and temperature are well documented, but correlations to other environmental parameters are less understood. This study identifies unique correlates (e.g., E-W wind scalar and harmful algal species) that could potentially inform the next iteration of predictive Vibrio models for the EMSS region. Additionally, these correlates may allow existing environmental monitoring efforts to be leveraged in providing data inputs for future Vibrio risk models. An observed correlation between salinity and V. vulnificus/particle-size associations suggests that predicted environmental changes may affect the abundance of Vibrio spp. in certain reservoirs, which may alter which vectors present the greatest vibrio risk.

Elevated concentrations of polymyxin B elicit a biofilm-specific resistance mechanism in Vibrio cholerae

Vibrio cholerae can form biofilms in the aquatic environment and in the human intestine, facilitating the release of hyper-infectious aggregates. Due to the increasing antibiotic resistance, alternatives need to be found. One of these alternatives is antimicrobial peptides, including polymyxin B (PmB). In this study, we first investigated the resistance of V. cholerae O1 El Tor strain A1552 to various antimicrobials under aerobic and anaerobic conditions. An increased resistance to PmB is observed in anaerobiosis, with a 3-fold increase in the dose required for 50 % growth inhibition. We then studied the impact of the PmB on the formation and the degradation of V. cholerae biofilms to PmB. Our results show that PmB affects more efficiently biofilm formation under anaerobic conditions. On the other hand, preformed biofilms are susceptible to degradation by PmB at concentrations close to the minimal inhibitory concentration. At higher concentrations, we observe an opacification of the biofilm structures within 20 min post-treatment, suggesting a densification of the structure. This densification does not seem to result from the overexpression of matrix genes but rather from DNA release through massive cell lysis, likely forming a protective shield that limits the penetration of the PmB into the biofilm.

Clinical surveillance systems obscure the true cholera infection burden in an endemic region

Our understanding of cholera transmission and burden largely relies on clinic-based surveillance, which can obscure trends, bias burden estimates and limit the impact of targeted cholera-prevention measures. Serological surveillance provides a complementary approach to monitoring infections, although the link between serologically derived infections and medically attended disease incidence-shaped by immunological, behavioral and clinical factors-remains poorly understood. We unravel this cascade in a cholera-endemic Bangladeshi community by integrating clinic-based surveillance, healthcare-seeking and longitudinal serological data through statistical modeling. Combining the serological trajectories with a reconstructed incidence timeline of symptomatic cholera, we estimated an annual Vibrio cholerae O1 infection incidence rate of 535 per 1,000 population (95% credible interval 514-556), with incidence increasing by age group. Clinic-based surveillance alone underestimated the number of infections and reported cases were not consistently correlated with infection timing. Of the infections, 4 in 3,280 resulted in symptoms, only 1 of which was reported through the surveillance system. These results impart insights into cholera transmission dynamics and burden in the epicenter of the seventh cholera pandemic, where >50% of our study population had an annual V. cholerae O1 infection, and emphasize the potential for a biased view of disease burden and infection risk when depending solely on clinical surveillance data.

Increased incidence of vibriosis in Maryland, U.S.A., 2006-2019

BACKGROUND

Vibrio spp. naturally occur in warm water with moderate salinity. Infections with non-cholera Vibrio (vibriosis) cause an estimated 80,000 illnesses and 100 fatalities each year in the United States. Climate associated changes to environmental parameters in aquatic ecosystems are largely promoting Vibrio growth, and increased incidence of vibriosis is being reported globally. However, vibriosis trends in the northeastern U.S. (e.g., Maryland) have not been evaluated since 2008.

METHODS

Vibriosis case data for Maryland (2006-2019; n = 611) were obtained from the COVIS database. Incidence rates were calculated using U.S. Census Bureau population estimates for Maryland. A logistic regression model, including region, age group, race, gender, occupation, and exposure type, was used to estimate the likelihood of hospitalization.

RESULTS

Comparing the 2006-2012 and 2013-2019 periods, there was a 39% (p = 0.01) increase in the average annual incidence rate (per 100,000 population) of vibriosis, with V. vulnificus infections seeing the greatest percentage increase (53%, p = 0.01), followed by V. parahaemolyticus (47%, p = 0.05). The number of hospitalizations increased by 58% (p = 0.01). Since 2010, there were more reported vibriosis cases with a hospital duration ≥10 days. Patients from the upper eastern shore region and those over the age of 65 were more likely (OR = 6.8 and 12.2) to be hospitalized compared to other patients.

CONCLUSIONS

Long-term increases in Vibrio infections, notably V. vulnificus wound infections, are occurring in Maryland. This trend, along with increased rates in hospitalizations and average hospital durations, underscore the need to improve public awareness, water monitoring, post-harvest seafood interventions, and environmental forecasting ability.

Recovering high-quality bacterial genomes from cross-contaminated cultures: a case study of marine Vibrio campbellii

BACKGROUND

Environmental monitoring of bacterial pathogens is critical for disease control in coastal marine ecosystems to maintain animal welfare and ecosystem function and to prevent significant economic losses. This requires accurate taxonomic identification of environmental bacterial pathogens, which often cannot be achieved by commonly used genetic markers (e.g., 16S rRNA gene), and an understanding of their pathogenic potential based on the information encoded in their genomes. The decreasing costs of whole genome sequencing (WGS), combined with newly developed bioinformatics tools, now make it possible to unravel the full potential of environmental pathogens, beyond traditional microbiological approaches. However, obtaining a high-quality bacterial genome, requires initial cultivation in an axenic culture, which is a bottleneck in environmental microbiology due to cross-contamination in the laboratory or isolation of non-axenic strains.

RESULTS

We applied WGS to determine the pathogenic potential of two Vibrio isolates from coastal seawater. During the analysis, we identified cross-contamination of one of the isolates and decided to use this dataset to evaluate the possibility of bioinformatic contaminant removal and recovery of bacterial genomes from a contaminated culture. Despite the contamination, using an appropriate bioinformatics workflow, we were able to obtain high quality and highly identical genomes (Average Nucleotide Identity value 99.98%) of one of the Vibrio isolates from both the axenic and the contaminated culture. Using the assembled genome, we were able to determine that this isolate belongs to a sub-lineage of Vibrio campbellii associated with several diseases in marine organisms. We also found that the genome of the isolate contains a novel Vibrio plasmid associated with bacterial defense mechanisms and horizontal gene transfer, which may offer a competitive advantage to this putative pathogen.

CONCLUSIONS

Our study shows that, using state-of-the-art bioinformatics tools and a sufficient sequencing effort, it is possible to obtain high quality genomes of the bacteria of interest and perform in-depth genomic analyses even in the case of a contaminated culture. With the new isolate and its complete genome, we are providing new insights into the genomic characteristics and functional potential of this sub-lineage of V. campbellii. The approach described here also highlights the possibility of recovering complete bacterial genomes in the case of non-axenic cultures or obligatory co-cultures.

Complex adaptive systems-based framework for modeling the health impacts of climate change

Introduction

Climate change is a global phenomenon with far-reaching consequences, and its impact on human health is a growing concern. The intricate interplay of various factors makes it challenging to accurately predict and understand the implications of climate change on human well-being. Conventional methodologies have limitations in comprehensively addressing the complexity and nonlinearity inherent in the relationships between climate change and health outcomes.

Objectives

The primary objective of this paper is to develop a robust theoretical framework that can effectively analyze and interpret the intricate web of variables influencing the human health impacts of climate change. By doing so, we aim to overcome the limitations of conventional approaches and provide a more nuanced understanding of the complex relationships involved. Furthermore, we seek to explore practical applications of this theoretical framework to enhance our ability to predict, mitigate, and adapt to the diverse health challenges posed by a changing climate.

Methods

Addressing the challenges outlined in the objectives, this study introduces the Complex Adaptive Systems (CAS) framework, acknowledging its significance in capturing the nuanced dynamics of health effects linked to climate change. The research utilizes a blend of field observations, expert interviews, key informant interviews, and an extensive literature review to shape the development of the CAS framework.

Results and discussion

The proposed CAS framework categorizes findings into six key sub-systems: ecological services, extreme weather, infectious diseases, food security, disaster risk management, and clinical public health. The study employs agent-based modeling, using causal loop diagrams (CLDs) tailored for each CAS sub-system. A set of identified variables is incorporated into predictive modeling to enhance the understanding of health outcomes within the CAS framework. Through a combination of theoretical development and practical application, this paper aspires to contribute valuable insights to the interdisciplinary field of climate change and health. Integrating agent-based modeling and CLDs enhances the predictive capabilities required for effective health outcome analysis in the context of climate change.

Conclusion

This paper serves as a valuable resource for policymakers, researchers, and public health professionals by employing a CAS framework to understand and assess the complex network of health impacts associated with climate change. It offers insights into effective strategies for safeguarding human health amidst current and future climate challenges.

A Quantitative and Qualitative Program Evaluation of a Case-Area Targeted Intervention to Reduce Cholera in Eastern Democratic Republic of the Congo

Individuals living near cholera patients have an increased risk of cholera infections. Case-area targeted interventions (CATIs) promoting improved water, sanitation, and hygiene (WASH) present a promising approach to reducing cholera for those residing near cholera cases. However, there is limited evidence on the effectiveness and implementation of this approach in increasing WASH behaviors. We conducted a mixed-methods program evaluation in rural and urban eastern Democratic Republic of the Congo. The quantitative component included household structured observations and spot checks in CATI and control areas to assess WASH conditions and behaviors. The qualitative component included semi-structured interviews with CATI recipients, non-recipients, and implementers to assess CATI implementation. A total of 399 participants were enrolled in the quantitative evaluation conducted within 1 month of CATI delivery. For the qualitative evaluation, 41 semi-structured interviews were conducted, 30 with individuals in CATI areas (recipients and non-recipients) and 11 with CATI implementers. Handwashing with soap was low among both CATI and control area participants (1% vs. 2%, p = 0.89). Significantly more CATI area households (75%) had chlorine tablets present compared to control area households (0%) (p < 0.0001); however, the percentage of households with stored water free chlorine concentrations > 0.2 mg/L was low for both CATI and control area households (11% vs. 6%, p = 0.45). Implementers reported an insufficient supply of soap for distribution to recipients and mistrust in the community of their activities. CATI recipients demonstrated low knowledge of the correct preparation and use of chlorine for water treatment. Recipients also indicated a need for CATI implementers to engage community leaders. As CATIs are part of cholera control plans in many cholera-endemic countries, it is important to evaluate existing programs and develop evidence-based approaches to deliver CATIs that are both tailored to the local context and engage affected communities to increase WASH behaviors to reduce the spread of cholera.

Genomic diversity of Vibrio spp. and metagenomic analysis of pathogens in Florida Gulf coastal waters following Hurricane Ian

IMPORTANCE

Evidence suggests warming temperatures are associated with the spread of potentially pathogenic Vibrio spp. and the emergence of human disease globally. Following Hurricane Ian, the State of Florida reported a sharp increase in the number of reported Vibrio spp. infections and deaths. Hence, monitoring of pathogens, including vibrios, and environmental parameters influencing their occurrence is critical to public health. Here, DNA sequencing was used to investigate the genomic diversity of Vibrio parahaemolyticus and Vibrio vulnificus, both potential human pathogens, in Florida coastal waters post Hurricane Ian, in October 2022. Additionally, the microbial community of water samples was profiled to detect the presence of Vibrio spp. and other microorganisms (bacteria, fungi, protists, and viruses) present in the samples. Long-term environmental data analysis showed changes in environmental parameters during and after Ian were optimal for the growth of Vibrio spp. and related pathogens. Collectively, results will be used to develop predictive risk models during climate change.

Anticipatory decision-making for cholera in Malawi

Climate change raises an old disease to a new level of public health threat. The causative agent, Vibrio cholerae, native to aquatic ecosystems, is influenced by climate and weather processes. The risk of cholera is elevated in vulnerable populations lacking access to safe water and sanitation infrastructure. Predictive intelligence, employing mathematical algorithms that integrate earth observations and heuristics derived from microbiological, sociological, and weather data, can provide anticipatory decision-making capabilities to reduce the burden of cholera and save human lives. An example offered here is the recent outbreak of cholera in Malawi, predicted in advance by such algorithms.

Flagella-related gene mutations in Vibrio cholerae during extended cultivation in nutrient-limited media impair cell motility and prolong culturability

IMPORTANCE

Vibrio cholerae undergoes a transition to a viable but non-culturable (VNC) state when subjected to various environmental stresses. We showed here that flagellar motility was involved in the development of the VNC state of V. cholerae. In this study, motility-defective isolates with mutations in various flagella-related genes, but not motile isolates, were predominantly obtained under the stress of long-term batch culture. Other genomic regions were highly conserved, suggesting that the mutations were selective. During the stationary phase of long-term culture, V. cholerae isolates with mutations in the acetate kinase and flagella-related genes were predominant. This study suggests that genes involved in specific functions in V. cholerae undergo mutations under certain environmental conditions.

Environmental Factors Associated with Incidence and Distribution of V. parahaemolyticus and V. vulnificus in Chesapeake Bay, Maryland, USA: A three-year case study

Members of the genus Vibrio are ecologically significant bacteria native to aquatic ecosystems globally, and a few can cause diseases in humans. Vibrio-related illnesses have increased in recent years, primarily attributed to changing environmental conditions. Therefore, understanding the role of environmental factors in the occurrence and growth of pathogenic strains is crucial for public health. Water, oyster, and sediment samples were collected between 2009 and 2012 from Chester River and Tangier Sound sites in Chesapeake Bay, Maryland, USA, to investigate the relationship between water temperature, salinity, and chlorophyll with the incidence and distribution of Vibrio parahaemolyticus (VP) and Vibrio vulnificus (VV). Odds ratio analysis was used to determine association between the likelihood of VP and VV presence and these environmental variables. Results suggested that water temperature threshold of 20°C or higher was associated with an increased risk, favoring the incidence of Vibrio spp. A significant difference in salinity was observed between the two sampling sites, with distinct ranges showing high odds ratio for Vibrio incidence, especially in water and sediment, emphasizing the impact of salinity on VP and VV incidence and distribution. Notably, salinity between 9-20 PPT consistently favored the Vibrio incidence across all samples. Relationship between chlorophyll concentrations and VP and VV incidence varied depending on sample type. However, chlorophyll range of 0-10 μg/L was identified as critical in oyster samples for both vibrios. Analysis of odds ratios for water samples demonstrated consistent outcomes across all environmental parameters, indicating water samples offer a more reliable indicator of Vibrio spp. incidence.

The Response Regulator VC1795 of Vibrio Pathogenicity Island-2 Contributes to Intestinal Colonization by Vibrio cholerae

Vibrio cholerae is an intestinal pathogen that can cause severe diarrheal disease. The disease has afflicted millions of people since the 19th century and has aroused global concern. The Vibrio Pathogenicity Island-2 (VPI-2) is a 57.3 kb region, VC1758-VC1809, which is present in choleragenic V. cholerae. At present, little is known about the function of VC1795 in the VPI-2 of V. cholerae. In this study, the intestinal colonization ability of the ΔVC1795 strain was significantly reduced compared to that of the wild-type strain, and the colonization ability was restored to the wild-type strain after VC1795 gene replacement. This result indicated that the VC1795 gene plays a key role in the intestinal colonization and pathogenicity of V. cholerae. Then, we explored the upstream and downstream regulation mechanisms of the VC1795 gene. Cyclic adenylate receptor protein (CRP) was identified as being located upstream of VC1795 by a DNA pull-down assay and electrophoretic mobility shift assays (EMSAs) and negatively regulating the expression of VC1795. In addition, the results of Chromatin immunoprecipitation followed by sequencing (ChIP-seq), EMSAs, and Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) indicated that VC1795 directly negatively regulates the expression of its downstream gene, VC1794. Furthermore, by using qRT-PCR, we hypothesized that VC1795 indirectly positively regulates the toxin-coregulated pilus (TCP) cluster to influence the colonization ability of V. cholerae in intestinal tracts. In short, our findings support the key regulatory role of VC1795 in bacterial pathogenesis as well as lay the groundwork for the further determination of the complex regulatory network of VC1795 in bacteria.

Precisely Controlling Csr sRNA Levels by MshH Enhances Vibrio cholerae Colonization in Adult Mice

Vibrio cholerae is the causative agent of cholera. Effective intestinal colonization is a key step for V. cholerae pathogenicity and transmission. In this study, we found that deleting mshH, a homolog of the Escherichia coli CsrD protein, caused a V. cholerae colonization defect in the intestine of adult mice. By analyzing the RNA levels of CsrB, CsrC, and CsrD, we found that deleting mshH increased the levels of CsrB and CsrD but decreased the level of CsrC. However, deleting CsrB and -D not only recovered the mshH deletion mutant colonization defect but also recovered CsrC to wild-type levels. These results indicated that controlling the RNA levels of CsrB, -C, and -D is crucial for V. cholerae colonization of adult mice. We further demonstrated that the RNA levels of CsrB and CsrD were mainly controlled by MshH-dependent degradation, yet the level of CsrC was mainly determined by the CsrA-dependent stabilization. Our data show that V. cholerae differentially controls CsrB, -C, and -D abundance through the MshH-CsrB/C/D-CsrA regulatory pathway to finely regulate the activity of CsrA targets such as ToxR, so as to better survive in adult mouse intestine. IMPORTANCE The ability of V. cholerae to colonize the intestine is a key factor for its fitness and transmissibility between hosts. Here, we investigated the mechanism of V. cholerae colonization of adult mammal intestine and found that precisely controlling the CsrB, -C, and -D contents by MshH and CsrA plays an essential role for V. cholerae colonization in the adult mouse intestine. These data expand our knowledge on the mechanism of V. cholerae controlling the RNA level of CsrB, -C, and -D and highlight the importance that the different strategies used by V. cholerae to regulate the RNA level of CsrB, -C, and -D confer the bacterium with a survival advantage.

Estimating the gap between clinical cholera and true community infections: findings from an integrated surveillance study in an endemic region of Bangladesh

Our understanding of cholera transmission and burden largely rely on clinic-based surveillance, which can obscure trends, bias burden estimates and limit the impact of targeted cholera-prevention measures. Serologic surveillance provides a complementary approach to monitoring infections, though the link between serologically-derived infections and medically-attended disease - shaped by immunological, behavioral, and clinical factors - remains poorly understood. We unravel this cascade in a cholera-endemic Bangladeshi community by integrating clinic-based surveillance, healthcare seeking, and longitudinal serological data through statistical modeling. We found >50% of the study population had a V. cholerae O1 infection annually, and infection timing was not consistently correlated with reported cases. Four in 2,340 infections resulted in symptoms, only one of which was reported through the surveillance system. These results provide new insights into cholera transmission dynamics and burden in the epicenter of the 7th cholera pandemic and provide a framework to synthesize serological and clinical surveillance data.

Ploidy in Vibrio natriegens: Very Dynamic and Rapidly Changing Copy Numbers of Both Chromosomes

Vibrio natriegens is the fastest-growing bacterium, with a doubling time of approximately 12-14 min. It has a high potential for basic research and biotechnological applications, e.g., it can be used for the cell-free production of (labeled) heterologous proteins, for synthetic biological applications, and for the production of various compounds. However, the ploidy level in V. natriegens remains unknown. At nine time points throughout the growth curve, we analyzed the numbers of origins and termini of both chromosomes with qPCR and the relative abundances of all genomic sites with marker frequency analyses. During the lag phase until early exponential growth, the origin copy number and origin/terminus ratio of chromosome 1 increased severalfold, but the increase was lower for chromosome 2. This increase was paralleled by an increase in cell volume. During the exponential phase, the origin/terminus ratio and cell volume decreased again. This highly dynamic and fast regulation has not yet been described for any other species. In this study, the gene dosage increase in origin-adjacent genes during the lag phase is discussed together with the nonrandom distribution of genes on the chromosomes of V. natriegens. Taken together, the results of this study provide the first comprehensive overview of the chromosome dynamics in V. natriegens and will guide the optimization of molecular biological characterization and biotechnological applications.

Coral Disease and Ingestion: Investigating the Role of Heterotrophy in the Transmission of Pathogenic Vibrio spp. using a Sea Anemone (Exaiptasia pallida) Model System

Understanding disease transmission in corals can be complicated given the intricacy of the holobiont and difficulties associated with ex situ coral cultivation. As a result, most of the established transmission pathways for coral disease are associated with perturbance (i.e., damage) rather than evasion of immune defenses. Here, we investigate ingestion as a potential pathway for the transmission of coral pathogens that evades the mucus membrane. Using sea anemones (Exaiptasia pallida) and brine shrimp (Artemia sp.) to model coral feeding, we tracked the acquisition of the putative pathogens, Vibrio alginolyticus, V. harveyi, and V. mediterranei using GFP-tagged strains. Vibrio sp. were provided to anemones using 3 experimental exposures (i) direct water exposure alone, (ii) water exposure in the presence of a food source (non-spiked Artemia), and (iii) through a "spiked" food source (Vibrio-colonized Artemia) created by exposing Artemia cultures to GFP-Vibrio via the ambient water overnight. Following a 3 h feeding/exposure duration, the level of acquired GFP-Vibrio was quantified from anemone tissue homogenate. Ingestion of spiked Artemia resulted in a significantly greater burden of GFP-Vibrio equating to an 830-fold, 3,108-fold, and 435-fold increase in CFU mL-1 when compared to water exposed trials and a 207-fold, 62-fold, and 27-fold increase in CFU mL-1 compared to water exposed with food trials for V. alginolyticus, V. harveyi, and V. mediterranei, respectively. These data suggest that ingestion can facilitate delivery of an elevated dose of pathogenic bacteria in cnidarians and may describe an important portal of entry for pathogens in the absence of perturbing conditions. IMPORTANCE The front line of pathogen defense in corals is the mucus membrane. This membrane coats the surface body wall creating a semi-impermeable layer that inhibits pathogen entry from the ambient water both physically and biologically through mutualistic antagonism from resident mucus microbes. To date, much of the coral disease transmission research has been focused on mechanisms associated with perturbance of this membrane such as direct contact, vector lesions (predation/biting), and waterborne exposure through preexisting lesions. The present research describes a potential transmission pathway that evades the defenses provided by this membrane allowing unencumbered entry of bacteria as in association with food. This pathway may explain an important portal of entry for emergence of idiopathic infections in otherwise healthy corals and can be used to improve management practices for coral conservation.

The concern about main crises such as the Covid-19 pandemic, the war in Ukraine, and climate change's impact on energy-saving behavior

The number of crises experienced around the world forces people to reconsider and reassess various aspects of their lives. The energy crisis caused by the war in Ukraine and uncontrolled climate change revealed the importance of energy-saving behavior. Thus, the aim of this paper is to analyze the concerns about current crises such as the Covid-19 pandemic, the war in Ukraine, and climate change's impact on energy-saving behavior and changes in environmental concern. Referring to the survey conducted in Lithuania in 2022, where 1000 respondents participated, the results revealed that the war in Ukraine was the most concerning problem. The level of climate change concern was slightly lower. Meanwhile, the Covid-19 pandemic was the least important problem in Lithuania in 2022. Furthermore, respondents stated that the Covid-19 pandemic contributed to the changes in environmental concern and energy-saving actions more than the war in Ukraine did. Meanwhile, the Generalized Linear Model results revealed that only the war in Ukraine positively and significantly influenced energy-saving behavior. The Covid-19 pandemic concern negatively affected energy-saving behavior, while the climate change concern factor affected it indirectly, as the interaction of attitudes toward energy consumption. Thus, this study revealed the main aspect of and how to encourage energy-saving behavior in the context of the main current crises.

Impact of pathogenic bacterial communities present in wastewater on aquatic organisms: Application of nanomaterials for the removal of these pathogens

Contaminated wastewater (WW) can cause severe hazards to numerous delicate ecosystems and associated life forms. In addition, human health is negatively impacted by the presence of microorganisms in water. Multiple pathogenic microorganisms in contaminated water, including bacteria, fungi, yeast, and viruses, are vectors for several contagious diseases. To avoid the negative impact of these pathogens, WW must be free from pathogens before being released into stream water or used for other reasons. In this review article, we have focused on pathogenic bacteria in WW and summarized the impact of the different types of pathogenic bacteria on marine organisms. Moreover, we presented a variety of physical and chemical techniques that have been developed to provide a pathogen-free aquatic environment. Among the techniques, membrane-based techniques for trapping hazardous biological contaminants are gaining popularity around the world. Besides, novel and recent advancements in nanotechnological science and engineering suggest that many waterborne pathogens could be inactivated using nano catalysts, bioactive nanoparticles, nanostructured catalytic membranes, nanosized photocatalytic structures, and electrospun nanofibers and processes have been thoroughly examined.

Modeling pH and Temperature Effects as Climatic Hazards in Vibrio Vulnificus and Vibrio Parahaemolyticus Planktonic Growth and Biofilm Formation

Climate-induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased Vibrio spread, exposure, and infection rates, thus facilitating greater Vibrio-human interactions. Multiple efforts have been developed to predict Vibrio exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on V. vulnificus and V. parahaemolyticus planktonic and biofilm growth. Vibrio strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl2 at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm Vibrio growth within- and between-species. This study showed that temperature and pH factors significantly affect Vibrio planktonic growth rates and V. parahaemolyticus biofilm formation. Therefore, pH effects must be added to the Vibrio growth modeling efforts to better predict Vibrio risk in estuarine and coastal zones that can potentially experience the cooccurrence of Vibrio and harmful algal bloom outbreak events.

A new generation of real-time environmental monitoring systems to study the impact of El Niño on disease dynamics

Global warming is drastically altering weather patterns, accentuating the frequency and strength of global events such as the El Niño Southern Oscillation. This alteration is driving the spread of diseases sensitive to climate such as diarrheal diseases. Environmental monitoring through remote sensing, in combination with data from epidemiological surveillance programs, is facilitating the study of infectious disease dynamics associated with El Niño. This integrative approach can inform the development of strategies for mitigating the impact of these diseases on public health. Here, we discuss some of the achievements of this approach in the management, control, and prevention of infectious diseases linked to El Niño.

Selection of G-rich ssDNA aptamers for the detection of enterotoxins of the cholera toxin family

Cholera and milder diarrheal disease are caused by Vibrio cholerae and enterotoxigenic Escherichia coli and are still a prominent public health concern. Evaluation of suspicious isolates is essential for the rapid containment of acute diarrhea outbreaks or prevention of epidemic cholera. Existing detection techniques require expensive equipment, trained personnel and are time-consuming. Antibody-based methods are also available, but cost and stability issues can limit their applications for point-of-care testing. This study focused on the selection of single stranded DNA aptamers as simpler, more stable and more cost-effective alternatives to antibodies for the co-detection of AB₅ toxins secreted by enterobacteria causing acute diarrheal infections. Cholera toxin and Escherichia coli heat-labile enterotoxin, the key toxigenicity biomarkers of these bacteria, were immobilized on magnetic beads and were used in a SELEX-based selection strategy. This led to the enrichment of sequences with a high % GC content and a dominant G-rich motif as revealed by Next Generation Sequencing. Enriched sequences were confirmed to fold into G-quadruplex structures and the binding of one of the most abundant candidates to the two enterotoxins was confirmed. Ongoing work is focused on the development of monitoring tools for potential environmental surveillance of epidemic choleraand milder diarrheal disease.

Genomic attributes of Vibrio cholerae O1 responsible for 2022 massive cholera outbreak in Bangladesh

In 2022, one of its worst cholera outbreaks began in Bangladesh and the icddr,b Dhaka hospital treated more than 1300 patients and ca. 42,000 diarrheal cases from March-1 to April-10, 20221. Here, we present genomic attributes of V. cholerae O1 responsible for the 2022 Dhaka outbreak and 960 7th pandemic El Tor (7PET) strains from 88 countries. Results show strains isolated during the Dhaka outbreak cluster with 7PET wave-3 global clade strains, but comprise subclade BD-1.2, for which the most recent common ancestor appears to be that responsible for recent endemic cholera in India. BD-1.2 strains are present in Bangladesh since 2016, but not establishing dominance over BD-2 lineage strains2 until 2018 and predominantly associated with endemic cholera. In conclusion, the recent shift in lineage and genetic attributes, including serotype switching of BD-1.2 from Ogawa to Inaba, may explain the increasing number of cholera cases in Bangladesh.

The Role of Nutrients and Nutritional Signals in the Pathogenesis of Vibrio cholerae

Vibrio cholerae, the agent of cholera, is a natural inhabitant of aquatic environments. Over the past decades, the importance of specific nutrients and micronutrients in the environmental survival, host colonization, and pathogenesis of this species has become increasingly clear. For instance, V. cholerae has evolved ingenious mechanisms that allow the bacterium to colonize and establish a niche in the intestine of human hosts, where it competes with commensals (gut microbiota) and other pathogenic bacteria for available nutrients. Here, we discuss the carbon and energy sources utilized by V. cholerae and what is known about the role of nutrition in V. cholerae colonization. We examine how nutritional signals affect virulence gene regulation and how interactions with intestinal commensal species can affect intestinal colonization.

When Vibrios Take Flight: A Meta-Analysis of Pathogenic Vibrio Species in Wild and Domestic Birds

Of the over 100 species in the genus Vibrio, approximately twelve are associated with clinical disease, such as cholera and vibriosis. Crucially, eleven of those twelve, including Vibrio cholerae and Vibrio vulnificus, have been isolated from birds. Since 1965, pathogenic Vibrio species have been consistently isolated from aquatic and ground-foraging bird species, which has implications for public health, as well as the One Health paradigm defined as an ecology-inspired, integrative framework for the study of health and disease, inclusive of environmental, human, and animal health. In this meta-analysis, we identified 76 studies from the primary literature which report on or examine birds as hosts for pathogenic Vibrio species. We found that the burden of disease in birds was most commonly associated with V. cholerae, followed by V. metschnikovii and V. parahaemolyticus. Meta-analysis wide prevalence of our Vibrio pathogens varied from 19% for V. parahaemolyticus to 1% for V. mimicus. Wild and domestic birds were both affected, which may have implications for conservation, as well as agriculturally associated avian species. As pathogenic Vibrios become more abundant throughout the world as a result of warming estuaries and oceans, susceptible avian species should be continually monitored as potential reservoirs for these pathogens.

Cholera Dynamics and the Emergence of Pandemic Vibrio cholerae

Cholera is a severe diarrheal disease caused by the aquatic bacterium Vibrio cholerae. Interestingly, to date, only one major clade has emerged to cause pandemic disease in humans: the clade that encompasses the strains from the O1 and O139 serogroups. In this chapter, we provide a comprehensive perspective on the virulence factors and mobile genetic elements (MGEs) associated with the emergence of pandemic V. cholerae strains and highlight novel findings such as specific genomic background or interactions between MGEs that explain their confined distribution. Finally, we discuss pandemic cholera dynamics contextualizing them within the evolution of the bacterium.

Combating cholera by building predictive capabilities for pathogenic Vibrio cholerae in Yemen

Cholera remains a global public health threat in regions where social vulnerabilities intersect with climate and weather processes that impact infectious Vibrio cholerae. While access to safe drinking water and sanitation facilities limit cholera outbreaks, sheer cost of building such infrastructure limits the ability to safeguard the population. Here, using Yemen as an example where cholera outbreak was reported in 2016, we show how predictive abilities for forecasting risk, employing sociodemographical, microbiological, and climate information of cholera, can aid in combating disease outbreak. An epidemiological analysis using Bradford Hill Criteria was employed in near-real-time to understand a predictive model's outputs and cholera cases in Yemen. We note that the model predicted cholera risk at least four weeks in advance for all governorates of Yemen with overall 72% accuracy (varies with the year). We argue the development of anticipatory decision-making frameworks for climate modulated diseases to design intervention activities and limit exposure of pathogens preemptively.

Vibrio floridensis sp. nov., a novel species closely related to the human pathogen Vibrio vulnificus isolated from a cyanobacterial bloom

A Gram-stain-negative, rod-shaped bacterial strain, designated Vibrio floridensis IRLE0018 (=NRRL B-65642=NCTC 14661), was isolated from a cyanobacterial bloom along the Indian River Lagoon (IRL), a large and highly biodiverse estuary in eastern Florida (USA). The results of phylogenetic, biochemical, and phenotypic analyses indicate that this isolate is distinct from species of the genus Vibrio with validly published names and is the closest relative to the emergent human pathogen, Vibrio vulnificus. Here, we present the complete genome sequence of V. floridensis strain IRLE0018 (4 535 135 bp). On the basis of the established average nucleotide identity (ANI) values for the determination of different species (ANI <95 %), strain IRLE0018, with an ANI of approximately 92 % compared with its closest relative, V. vulnificus, represents a novel species within the genus Vibrio. To our knowledge, this represents the first time this species has been described. The results of genomic analyses of V. floridensis IRLE0018 indicate the presence of antibiotic resistance genes and several known virulence factors, however, its pathogenicity profile (e.g. survival in serum, phagocytosis avoidance) reveals limited virulence potential of this species in contrast to V. vulnificus.

Zooplankton act as cruise ships promoting the survival and pathogenicity of pathogenic bacteria

Bacteria in general interact with zooplankton in aquatic ecosystems. These zooplankton-bacterial interactions help to shape the bacterial community by regulating bacterial abundances. Such interactions are even more significant and crucially in need of investigation in the case of pathogenic bacteria, which cause severe diseases in humans and animals. Among the many associations between a host metazoan and pathogenic bacteria, zooplankton provide nutrition and protection from stressful conditions, promote the horizontal transfer of virulence genes, and act as a mode of pathogen transport. These interactions allow the pathogen to survive and proliferate in aquatic environments and to endure water treatment processes, thereby creating a potential risk to human health. This review highlights current knowledge on the contributions of zooplankton to the survival and pathogenicity of pathogenic bacteria. We also discuss the need to consider these interactions as a risk factor in water treatment processes.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

An Assessment of Household Knowledge and Practices during a Cholera Epidemic- Dar es Salaam, Tanzania, 2016

From August 15, 2015 to March 5, 2016, Tanzania reported 16,521 cholera cases and 251 deaths, with 4,596 cases and 44 deaths in its largest city, Dar es Salaam. To evaluate outbreak response efforts, we conducted a household survey with drinking water testing in the five most affected wards in Dar es Salaam. We interviewed 641 households 6 months after the beginning of the outbreak. Although most respondents knew that cholera causes diarrhea (90%) and would seek care if suspecting cholera (95%), only 45% were aware of the current outbreak in the area and only 5% would use oral rehydration salts (ORS) if ill. Of 200 (31%) respondents reporting no regular water treatment, 46% believed treatment was unnecessary and 18% believed treatment was too expensive. Fecal contamination was found in 45% of water samples and was associated with water availability (P = 0.047). Only 11% of samples had detectable free chlorine residual, which was associated with water availability (P = 0.025), reported current water treatment (P = 0.006), and observed free chlorine product in the household (P = 0.015). The provision of accessible, adequately chlorinated water supply, and implementation of social mobilization campaigns advocating household water treatment and use of ORS should be prioritized to address gaps in cholera prevention and treatment activities.

Heterogeneous Growth Enhancement of Vibrio cholerae in the Presence of Different Phytoplankton Species

Vibrio cholerae is a ubiquitously distributed human pathogen that naturally inhabits marine and estuarine ecosystems. Two serogroups are responsible for causing cholera epidemics, O1 and O139, but several non-O1 and non-O139 V. cholerae (NOVC) strains can induce cholera-like infections. Outbreaks of V. cholerae have previously been correlated with phytoplankton blooms; however, links to specific phytoplankton species have not been resolved. Here, the growth of a NOVC strain (S24) was measured in the presence of different phytoplankton species, alongside phytoplankton abundance and concentrations of dissolved organic carbon (DOC). During 14-day experiments, V. cholerae S24 was cocultured with strains of the axenic phytoplankton species Actinocyclus curvatulus, Cylindrotheca closterium, a Pseudoscourfieldia sp., and a Picochlorum sp. V. cholerae abundances significantly increased in the presence of A. curvatulus, C. closterium, and the Pseudoscourfieldia sp., whereas abundances significantly decreased in the Picochlorum sp. coculture. V. cholerae growth was significantly enhanced throughout the cogrowth experiment with A. curvatulus, whereas when grown with C. closterium and the Pseudoscourfieldia sp., growth only occurred during the late stationary phase of the phytoplankton growth cycle, potentially coinciding with a release of DOC from senescent phytoplankton cells. In each of these cases, significant correlations between phytoplankton-derived DOC and V. cholerae cell abundances occurred. Notably, the presence of V. cholerae also promoted the growth of A. curvatulus and Picochlorum spp., highlighting potential ecological interactions. Variations in abundances of NOVC identified here highlight the potential diversity in V. cholerae-phytoplankton ecological interactions, which may inform efforts to predict outbreaks of NOVC in coastal environments. IMPORTANCE Many environmental strains of V. cholerae do not cause cholera epidemics but remain a public health concern due to their roles in milder gastrointestinal illnesses. With emerging evidence that these infections are increasing due to climate change, determining the ecological drivers that enable outbreaks of V. cholerae in coastal environments is becoming critical. Links have been established between V. cholerae abundance and chlorophyll a levels, but the ecological relationships between V. cholerae and specific phytoplankton species are unclear. Our research demonstrated that an environmental strain of V. cholerae (serogroup 24) displays highly heterogenous interactions in the presence of different phytoplankton species with a relationship to the dissolved organic carbon released by the phytoplankton species. This research points toward the complexity of the interactions of environmental strains of V. cholerae with phytoplankton communities, which we argue should be considered in predicting outbreaks of this pathogen.

Cholera in Haiti

The cholera epidemic that hit Haiti from October 2010 to February 2019 was the world's deadliest of the last 25 years. Officially, the successive waves caused 9789 deaths, although numerous additional casualties could not be recorded. The origin of this epidemic has been the subject of a controversy involving two opposing theories. The first hypothesis, put forward by renowned American academics, was that the cholera epidemic originated from the environment, due to the proliferation and transmission of aquatic Vibrio cholerae bacteria driven by a confluence of circumstances, i.e., the earthquake followed by a hot summer and, ultimately, heavy rainfall and flooding. The alternative hypothesis, which was subsequently confirmed by epidemiological and genomic studies, attributed the epidemic to the recent importation of cholera by UN peacekeepers having recently arriving from Nepal, and to a river polluted with sewage. In late 2016, the Secretary General of the United Nations finally begged the Haitian people for forgiveness. This implicit recognition of the role of the UN in the cholera epidemic helped to fund the ongoing fight against it. Case-area targeted interventions aimed at interrupting cholera transmission were reinforced, which resulted in the extinction of the epidemic within two years. In the meantime, several phylogenetic studies on Vibrio cholerae during the seventh cholera pandemic demonstrated that local environmental and global epidemic Vibrio populations were distinct. These studies also showed that epidemics arose when the bacterium had diversified and that it had spread during transmission events associated with human travel.

Cholera

Cholera was first described in the areas around the Bay of Bengal and spread globally, resulting in seven pandemics during the past two centuries. It is caused by toxigenic Vibrio cholerae O1 or O139 bacteria. Cholera is characterised by mild to potentially fatal acute watery diarrhoeal disease. Prompt rehydration therapy is the cornerstone of management. We present an overview of cholera and its pathogenesis, natural history, bacteriology, and epidemiology, while highlighting advances over the past 10 years in molecular epidemiology, immunology, and vaccine development and deployment. Since 2014, the Global Task Force on Cholera Control, a WHO coordinated network of partners, has been working with several countries to develop national cholera control strategies. The global roadmap for cholera control focuses on stopping transmission in cholera hotspots through vaccination and improved water, sanitation, and hygiene, with the aim to reduce cholera deaths by 90% and eliminate local transmission in at least 20 countries by 2030.

Mechanisms Generating Dichotomies in the Life Strategies of Heterotrophic Marine Prokaryotes

Understanding the mechanisms that generate and maintain diversity in marine prokaryotic communities is one of the main challenges for contemporary marine microbiology. We here review how observational, experimental, and theoretical evidence converge on the conclusion that the marine pelagic community of heterotrophic prokaryotes consists of organisms with two main types of life strategies. We illustrate this dichotomy by SAR11 and Vibrio spp. as typical representatives of the two strategies. A theory for life strategy dichotomy exists in classical r/K-selection. We here discuss an additional dichotomy introduced by what we term S/L-selection (for Small and Large, respectively). While r/K-selection focuses on the role of environmental disturbances, steady-state models suggest that high abundance at species level should be closely related to a low trade-off between competition and defense. We summarize literature indicating that the high availability of organic C is an essential environmental factor favoring Vibrio spp. and suggest that the essence of the generalized L-strategy is to reduce the competition-predator defense trade-off by using non-limiting organic C to increase size. The “streamlining” theory that has been suggested for the S-strategist SAR11 proposes the opposite: that low trade-off is achieved by a reduction in size. We show how this apparent contradiction disappears when the basic assumptions of diffusion-limited uptake are considered. We propose a classification scheme that combines S/L and r/K-selection using the two dimensions of organic C availability and environmental disturbance. As organic C in terrestrial runoff and size of the oligotrophic oceanic gyres are both changing, habitat size for both S- and L-strategists are affected by global change. A theory capturing the main aspects of prokaryote life strategies is therefore crucial for predicting responses of the marine microbial food web to climate change and other anthropogenic influences.

Membrane Efflux Pumps of Pathogenic Vibrio Species: Role in Antimicrobial Resistance and Virulence

Infectious diseases caused by bacterial species of the Vibrio genus have had considerable significance upon human health for centuries. V. cholerae is the causative microbial agent of cholera, a severe ailment characterized by profuse watery diarrhea, a condition associated with epidemics, and seven great historical pandemics. V. parahaemolyticus causes wound infection and watery diarrhea, while V. vulnificus can cause wound infections and septicemia. Species of the Vibrio genus with resistance to multiple antimicrobials have been a significant health concern for several decades. Mechanisms of antimicrobial resistance machinery in Vibrio spp. include biofilm formation, drug inactivation, target protection, antimicrobial permeability reduction, and active antimicrobial efflux. Integral membrane-bound active antimicrobial efflux pump systems include primary and secondary transporters, members of which belong to closely related protein superfamilies. The RND (resistance-nodulation-division) pumps, the MFS (major facilitator superfamily) transporters, and the ABC superfamily of efflux pumps constitute significant drug transporters for investigation. In this review, we explore these antimicrobial transport systems in the context of Vibrio spp. pathogenesis and virulence.