Molecular identification of Proteus mirabilis, Vibrio species leading to CRISPR-Cas9 modification of tcpA and UreC genes causing cholera and UTI

Heavy metal accumulation increases rapidly in the environment due to anthropogenic activities and industrialization. The leather and surgical industry produces many contaminants containing heavy metals. Cadmium, a prominent contaminant, is linked to severe health risks, notably kidney and liver damage, especially among individuals exposed to contaminated wastewater. This study aims to leverage the natural cadmium resistance mechanisms in bacteria for bioaccumulation purposes. The industrial wastewater samples, characterized by an alarming cadmium concentration of 29.6 ppm, 52 ppm, and 76.4 ppm-far exceeding the recommended limit of 0.003 ppm-were subjected to screening for cadmium-resistant bacteria using cadmium-supplemented media with CdCl2. 16S rRNA characterization identified Vibrio cholerae and Proteus mirabilis as cadmium-resistant bacteria in the collected samples. Subsequently, the cadmium resistance-associated cadA gene was successfully amplified in Vibrio species and Proteus mirabilis, revealing a product size of 623 bp. Further analysis of the identified bacteria included the examination of virulent genes, specifically the tcpA gene (472 bp) associated with cholera and the UreC gene (317 bp) linked to urinary tract infections. To enhance the bioaccumulation of cadmium, the study proposes the potential suppression of virulent gene expression through in-silico gene-editing tools such as CRISPR-Cas9. A total of 27 gRNAs were generated for UreC, with five selected for expression. Similarly, 42 gRNA sequences were generated for tcpA, with eight chosen for expression analysis. The selected gRNAs were integrated into the lentiCRISPR v2 expression vector. This strategic approach aims to facilitate precise gene editing of disease-causing genes (tcpA and UreC) within the bacterial genome. In conclusion, this study underscores the potential utility of Vibrio species and Proteus mirabilis as effective candidates for the removal of cadmium from industrial wastewater, offering insights for future environmental remediation strategies.

Spatiotemporal dynamics of cholera epidemics in Ethiopia: 2015-2021

Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly understood. This study aimed to describe cholera outbreak characteristics in Ethiopia from 2015 to 2021. During this period, Ethiopia experienced four epidemic waves. The first wave involved nationwide outbreaks during the second half of 2016 followed by outbreaks predominantly affecting Somali Region in 2017. The second wave primarily affected Tigray and Afar Regions. During the third wave, multiple smaller-scale outbreaks occurred during 2019. The fourth wave was limited to Bale Zone (Oromia Region) in 2021. Overall, a north to south shift was observed over the course of the study period. Major cholera transmission factors included limited access to safe water and sanitation facilities. Severe weather events (drought and flooding) appear to aggravate cholera diffusion. Cholera transmission between Ethiopia and nearby countries (Kenya and Somalia), likely plays a major role in regional cholera dynamics. Overall, this study provides the first understanding of recent spatiotemporal cholera dynamics in Ethiopia to inform cholera control and elimination strategies.

Total Synthesis of Vibrio Cholerae O43 Tetrasaccharide Repeating Unit

Vibrio cholerae is a pathogen responsible for the deadly pandemic - cholera. The glycans present on the surface of various strains of V. cholerae are considered as potential vaccine candidates. The tetrasaccharide repeating unit (RU) of V. cholerae O43 is decorated with less-explored rare deoxy amino sugars like d-quinosamine and d-viosamine, along with a rare amino acid, N-acetyl-l-allothreonine. Herein, we report a detailed account of the total synthesis of V. cholerae O43 tetrasaccharide RU. In our earlier attempt, while a one-pot assembly of trisaccharide was successful, the final coupling with a fully functionalized d-viosamine donor was low yielding. The successful route involved employing the Fmoc-protected d-viosamine building block as a donor and a late-stage amide bond formation of the tetrasaccharide.

Whole genome sequence of Vibrio cholerae NB-183 isolated from freshwater in Ontario, Canada harbors a unique gene repertoire

OBJECTIVE

Vibrio cholerae is an enteric pathogen that poses a significant threat to global health. It causes severe dehydrating diarrheal disease cholera in humans. V. cholerae could be acquired either from consuming contaminated seafood or direct contact with polluted waters. As part of a larger program that assesses the microbial community profile in aquatic systems, V. cholerae strain NB-183 was isolated and characterized using a combination of culture- and whole-genome sequencing-based approaches.

DATA DESCRIPTION

Here we report the assembled and annotated whole-genome sequence of a V. cholerae strain NB-183 isolated from a recreational freshwater lake in Ontario, Canada. The genome was sequenced using short-read Illumina systems. The whole-genome sequencing yielded 4,112,549 bp genome size with 99 contigs with an average genome coverage of 96× and 47.42% G + C content. The whole genome-based comparison, phylogenomic and gene repertoire indicates that this strain harbors multiple virulence genes and biosynthetic gene clusters. This genome sequence and its associated datasets provided in this study will be an indispensable resource to enhance the understanding of the functional, ecological, and evolutionary dynamics of V. cholerae.

Sugar-binding and split domain combinations in repeats-in-toxin adhesins from Vibrio cholerae and Aeromonas veronii mediate cell-surface recognition and hemolytic activities

Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent Vibrio cholerae, flagellar-regulated hemagglutinin A (FrhA) enables these functions. Using bioinformatic analysis, a sugar-binding domain was identified in FrhA adjacent to a domain of unknown function. AlphaFold2 indicated the boundaries of both domains to be slightly shorter than previously predicted and assisted in the recognition of the unknown domain as a split immunoglobulin-like fold that can assist in projecting the sugar-binding domain toward its target. The AlphaFold2-predicted structure is in excellent agreement with the molecular envelope obtained from small-angle X-ray scattering analysis of a recombinant construct spanning the sugar-binding and unknown domains. This two-domain construct was probed by glycan micro-array screening and showed binding to mammalian fucosylated glycans, some of which are characteristic erythrocyte markers and intestinal cell epitopes. Isothermal titration calorimetry further showed the construct-bound l-fucose with a Kd of 21 µM. Strikingly, this recombinant protein construct bound and lysed erythrocytes in a concentration-dependent manner, and its hemolytic activity was blocked by the addition of l-fucose. A protein ortholog construct from Aeromonas veronii was also produced and showed a similar glycan-binding pattern, binding affinity, erythrocyte-binding, and hemolytic activities. As demonstrated here with Hep-2 cells, fucose-based inhibitors of this sugar-binding domain can potentially be developed to block colonization by V. cholerae and other pathogenic bacteria that share this adhesin domain.IMPORTANCEThe bacterium, Vibrio cholerae, which causes cholera, uses an adhesion protein to stick to human cells and begin the infection process. One part of this adhesin protein binds to a particular sugar, fucose, on the surface of the target cells. This binding can lead to colonization and killing of the cells by the bacteria. Adding l-fucose to the bacteria before they bind to the human cells can prevent attachment and has promise as a preventative drug to protect against cholera.

The intersection between host-pathogen interactions and metabolism during Vibrio cholerae infection

Vibrio cholerae (V. cholerae), the etiological agent of cholera, uses cholera toxin (CT) to cause severe diarrheal disease. Cholera is still a significant cause of mortality worldwide with about half of all cholera cases and deaths occurring in children under five. Owing to the lack of cost-effective vaccination and poor vaccine efficacy in children, there is a need for alternative preventative and therapeutic strategies. Recent advances in our knowledge of the interplay between CT-induced disease and host-pathogen metabolism have opened the door for investigating how modulation of intestinal metabolism by V. cholerae during disease impacts host intestinal immunity, the gut microbiota, and pathogen-phage interactions. In this review article, we examine recent progress in our understanding of host-pathogen interactions during V. cholerae infection and discuss future work deciphering how modulation of gut metabolism during cholera intersects these processes to enable successful fecal-oral transmission of the pathogen.

In Commemoration of Dr. Mostafa Pourtaghva Shahrestani, a Pioneer in Infectious Disease Research

It is important to honor the contributions of scientific leaders who have dedicated their lives to advancing knowledge and serving their country. One way is to document their experiences and personalities in a documentary format, which can serve as a historical record and an inspiration for future generations. Dr. Mostafa Pourtaghva Shahrestani, a renowned physician and specialist in infectious diseases and tropical medicine, has made significant contributions to public health in Iran. He has played a crucial role in controlling infectious diseases such as smallpox, tuberculosis, rabies, plague, and cholera. Throughout his career, he has held various executive positions, including the head of Pasteur Hospital and the director of the Pasteur Institute of Iran. Dr. Pourtaghva's life is a testament to his unwavering dedication to public health services, as evidenced by his continuous effort, love, and interest in honest work. His inspiring story can serve as a model for those who seek to follow in his footsteps.

Emergence of multidrug resistant, ctx negative seventh pandemic Vibrio cholerae O1 El Tor sequence type (ST) 69 in coastal water of Kerala, India

Seventh pandemic Vibrio choleare O1 El Tor strain is responsible for the on-going pandemic outbreak of cholera globally. This strain evolved from non-pathogenic V. cholerae by acquiring seventh pandemic gene (VC 2346), pandemic Islands (VSP1 and VSP2), pathogenicity islands (VP1 and VP2) and CTX prophage region. The cholera toxin production is mainly attributed to the presence of ctx gene in these strains. However, several variants of this strain emerged as hybrid strains or atypical strains. The present study aimed to assess the aquatic environment of Cochin, India, over a period of 5 years for the emergence of multidrug resistant V. cholerae and its similarity with seventh pandemic strain. The continuous surveillance and monitoring resulted in the isolation of ctx negative, O1 positive V. cholerae isolate (VC6) from coastal water, Cochin, Kerala. The isolate possessed the biotype specific O1 El Tor tcpA gene and lacked other biotype specific ctx, zot, ace and rst genes. Whole genome analysis revealed the isolate belongs to pandemic sequence type (ST) 69 with the possession of pandemic VC2346 gene, pathogenic island VPI1, VPI2, and pandemic island VSP1 and VSP2. The isolate possessed several insertion sequences and the SXT/R391 family related Integrative Conjugative Elements (ICEs). In addition to this, the isolate genome carried virulence genes such as VgrG, mshA, ompT, toxR, ompU, rtxA, als, VasX, makA, and hlyA and antimicrobial resistance genes such as gyrA, dfrA1, strB, parE, sul2, parC, strA, VC1786ICE9-floR, and catB9. Moreover, the phylogenetic analysis suggests that the isolate genome is more closely related to seventh pandemic V. cholerae O1 N16961 strain. This study reports the first incidence of environmental ctx negative seventh pandemic V. choleare O1 El Tor isolate, globally and its presence in the aquatic system likely to induce toxicity in terms of public health point of view. The presence of this isolate in the aquatic environment warns the strict implementation of the epidemiological surveillance on the occurrence of emerging strains and the execution of flagship program for the judicious use of antibiotics in the aquatic ecosystem.

Mg2+ supplementation treats secretory diarrhea in mice by activating calcium-sensing receptor in intestinal epithelial cells

Cholera is a global health problem with no targeted therapies. The Ca2+-sensing receptor (CaSR) is a regulator of intestinal ion transport and a therapeutic target for diarrhea, and Ca2+ is considered its main agonist. We found that increasing extracellular Ca2+ had a minimal effect on forskolin-induced Cl- secretion in human intestinal epithelial T84 cells. However, extracellular Mg2+, an often-neglected CaSR agonist, suppressed forskolin-induced Cl- secretion in T84 cells by 65% at physiological levels seen in stool (10 mM). The effect of Mg2+ occurred via the CaSR/Gq signaling that led to cAMP hydrolysis. Mg2+ (10 mM) also suppressed Cl- secretion induced by cholera toxin, heat-stable E. coli enterotoxin, and vasoactive intestinal peptide by 50%. In mouse intestinal closed loops, luminal Mg2+ treatment (20 mM) inhibited cholera toxin-induced fluid accumulation by 40%. In a mouse intestinal perfusion model of cholera, addition of 10 mM Mg2+ to the perfusate reversed net fluid transport from secretion to absorption. These results suggest that Mg2+ is the key CaSR activator in mouse and human intestinal epithelia at physiological levels in stool. Since stool Mg2+ concentrations in patients with cholera are essentially zero, oral Mg2+ supplementation, alone or in an oral rehydration solution, could be a potential therapy for cholera and other cyclic nucleotide-mediated secretory diarrheas.

Cholera intoxication of human enteroids reveals interplay between decoy and functional glycoconjugate ligands

Prior research on cholera toxin (CT) binding and intoxication has relied on human colonic cancer derived epithelial cells. While these transformed cell lines have been beneficial, they neither derive from small intestine where intoxication occurs, nor represent the diversity of small intestinal epithelial cells (SI-ECs) and variation in glycoconjugate expression among individuals. Here, we used human enteroids, derived from jejunal biopsies of multipledonors to study CT binding and intoxication of human non-transformed SI-ECs. We modulated surface expression of glycosphingolipids, glycoproteins and specific glycans to distinguish the role of each glycan/glycoconjugate. Cholera-toxin-subunit-B (CTB) mutants were generated to decipher the preference of each glycoconjugate to different binding sites and the correlation between CT binding and intoxication. Human enteroids contain trace amounts of GM1, but other glycosphingolipids may be contributing to CT intoxication. We discovered that inhibition of either fucosylation or O-glycosylation sensitize enteroids to CT-intoxication. This can either be a consequence of the removal of fucosylated "decoy-like-ligands" binding to CTB's non-canonical site and/or increase in the availability of Gal/GalNAc-terminating glycoconjugates binding to the canonical site. Furthermore, simultaneous inhibition of fucosylation and O-glycosylation increased the availability of additional Gal/GalNAc-terminating glycoconjugates but counteracted the sensitization in CT intoxication caused by inhibiting O-glycosylation because of reduction in fucose. This implies a dual role of fucose as a functional glycan and a decoy, the interplay of which influences CT binding and intoxication. Finally, while the results were similar for enteroids from different donors, they were not identical, pointing to a role for human genetic variation in determining sensitivity to CT.

Recovery of Vibrio cholerae polarized cellular organization after exit from a non-proliferating spheroplast state

Vibrio cholerae, the causative agent of cholera epidemics, is a rod-shaped bacterium with a highly polarized cellular organization. It can survive harmful growth conditions by entering a non-proliferating spheroplast state, which involves loss of the cell envelope and polarity. How polarized rod organization cells are formed when the spheroplasts exit the non-proliferating state remains largely uncharacterized. To address this question, we investigated how L-arabinose-induced V. cholerae spheroplasts return to growth. We found that de novo morphogenesis started with the elimination of an excess of periplasm, which was immediately followed by cell elongation and the formation of cell branches with a diameter similar to that of normal V. cholerae cells. Periplasm elimination was driven by bifunctional peptidoglycan synthases involved in cell-wall maintenance, the aPBPs. Elongation and branching relied on the MreB-associated monofunctional peptidoglycan synthase PBP2. The cell division monofunctional peptidoglycan synthase FtsI was not involved in any of these processes. However, the FtsK cell division protein specifically targeted the sites of vesicle extrusion. Genetic material was amplified by synchronous waves of DNA replication as periplasmic elimination began. The HubP polarity factor targeted the tip of the branches as they began to form. However, HubP-mediated polarization was not involved in the efficiency of the recovery process. Finally, our results suggest that the positioning of HubP and the activities of the replication terminus organizer of the two V. cholerae chromosomes, MatP, are independent of cell division. Taken together, these results confirm the interest of L-arabinose-induced V. cholerae spheroplasts to study how cell shape is generated and shed light on the de novo establishment of the intracellular organization and cell polarization in V. cholerae.

Vibrio cholerae phage ICP3 requires O1 antigen for infection

In its natural aquatic environment, the bacterial pathogen Vibrio cholerae, the causative agent of the enteric disease cholera, is in constant competition with bacterial viruses known as phages. Following ICP3 infection, V. cholerae cultures that exhibited phage killing always recovered overnight, and clones isolated from these regrowth populations exhibited complete resistance to subsequent infections. Whole-genome sequencing of these resistant mutants revealed seven distinct mutations in genes encoding for enzymes involved in O1 antigen biosynthesis, demonstrating that the O1 antigen is a previously uncharacterized putative receptor of ICP3. To further elucidate the specificity of the resistance conferred by these mutations, they were challenged with the V. cholerae-specific phages ICP1 and ICP2. All seven O1 antigen mutants demonstrated pan-resistance to ICP1 but not ICP2, which utilizes the OmpU outer membrane protein as a receptor. We show that resistant mutations to ICP1 and ICP3 evolve at a significantly higher frequency than ICP2, but these mutations have a significant fitness tradeoff to V. cholerae and are unable to evolve in the presence of an antimicrobial that mimics host cell defensins.

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.

Characterization of a Nonagglutinating Toxigenic Vibrio cholerae Isolate

Toxigenic Vibrio cholerae serogroup O1 is the etiologic agent of the disease cholera, and strains of this serogroup are responsible for pandemics. A few other serogroups have been found to carry cholera toxin genes-most notably, O139, O75, and O141-and public health surveillance in the United States is focused on these four serogroups. A toxigenic isolate was recovered from a case of vibriosis from Texas in 2008. This isolate did not agglutinate with any of the four different serogroups' antisera (O1, O139, O75, or O141) routinely used in phenotypic testing and did not display a rough phenotype. We investigated several hypotheses that might explain the recovery of this potential nonagglutinating (NAG) strain using whole-genome sequencing analysis and phylogenetic methods. The NAG strain formed a monophyletic cluster with O141 strains in a whole-genome phylogeny. Furthermore, a phylogeny of ctxAB and tcpA sequences revealed that the sequences from the NAG strain also formed a monophyletic cluster with toxigenic U.S. Gulf Coast (USGC) strains (O1, O75, and O141) that were recovered from vibriosis cases associated with exposures to Gulf Coast waters. A comparison of the NAG whole-genome sequence showed that the O-antigen-determining region of the NAG strain was closely related to those of O141 strains, and specific mutations were likely responsible for the inability to agglutinate. This work shows the utility of whole-genome sequence analysis tools for characterization of an atypical clinical isolate of V. cholerae originating from a USGC state. IMPORTANCE Clinical cases of vibriosis are on the rise due to climate events and ocean warming (1, 2), and increased surveillance of toxigenic Vibrio cholerae strains is now more crucial than ever. While traditional phenotyping using antisera against O1 and O139 is useful for monitoring currently circulating strains with pandemic or epidemic potential, reagents are limited for non-O1/non-O139 strains. With the increased use of next-generation sequencing technologies, analysis of less well-characterized strains and O-antigen regions is possible. The framework for advanced molecular analysis of O-antigen-determining regions presented herein will be useful in the absence of reagents for serotyping. Furthermore, molecular analyses based on whole-genome sequence data and using phylogenetic methods will help characterize both historical and novel strains of clinical importance. Closely monitoring emerging mutations and trends will improve our understanding of the epidemic potential of Vibrio cholerae to anticipate and rapidly respond to future public health emergencies.

Current status of infectious diseases among migrants and non-citizens in Malaysia

The mass movement of migrants to Malaysia for employment is one of the factors contributing to the emergence and re-emergence of infectious diseases in this country. Despite mandatory health screening for migrants seeking employment, prevalence records of infectious diseases amongst migrant populations in Malaysia are still within negligible proportions. Therefore, the present review highlights the incidence, mortality and overall status of infectious diseases amongst migrants' populations in Malaysia, which maybe be useful for impeding exacerbation of inequalities among them and improving our national health system thru robust and effective emergency responses in controlling the prevalent diseases found among these populations and maybe, Malaysian citizens too. Peer-reviewed articles from January 2016 to December 2020 were searched through online platform including SCOPUS, PubMed, Science Direct, and Google Scholar. Non-peer-reviewed reports and publications from ministry and government websites including data from related agencies were also scoured from in order to ensure that there are no cases being overlooked, as most published articles did not have migrants as the research subjects. A total of 29 studies had been selected in the final analysis. Migrants in Malaysia were at higher risk for tuberculosis, malaria, lymphatic filariasis, cholera, leprosy and leptospirosis. Lymphatic filariasis was still endemic among this population while thousand cases of TB and cholera had been reported among them due to cramp living conditions and poor sanitation in their settlements respectively. While malaria had gradually decreased and become sporadic, the influx of migrant workers had led to the rising of imported malaria cases. Low cases of leprosy had been recorded in Malaysia but a significant proportion of it was contributed by migrant workers. As for leptospirosis, studies found that there are prominent cases among migrant workers, which particularly highest within workers with lower educational attainment. Infectious diseases are still prevalent among migrants in Malaysia due to various interplay factors including their working sectors, country of origin, immunization status, type of settlement, impoverished living conditions, and language and cultural barriers that impeding access to health facilities.

Transcriptome-wide identification and characterization of the Macrobrachium rosenbergii microRNAs potentially related to immunity against non-O1 Vibrio cholerae infection

Non-O1 Vibrio cholerae, a member of the Vibrio family, could cause gastrointestinal infection of Macrobrachium rosenbergii and result in significant economic losses. However, few studies on microRNA immunity related to non-O1 V. cholerae infection of M. rosenbergii. The aim of this study was to elucidate the mechanism of miRNA in the potential immune response of M. rosenbergii. to non-O1 V. cholerae MSVC-GY01 infection by transcriptome sequencing. Following quality screening, the control group received 10, 616, 712 clean reads, whereas the infected group received 9,727,616. The miRNA sequences in the two samples are extremely consistent and have a length of roughly 23 nt. In all, 871 known miRNAs were discovered, with 279 differentially expressed miRNAs (DEMs). Meanwhile, 62 novel miRNAs were predicted, including 43 DEMs. In order to understand the immune-related biological functions of DEMs, target genes were predicted. Pathway function annotation analysis showed that non-O1 V. cholerae affected the NOD-like receptor signaling pathway, RIG-I-like receptor signaling pathway, and Toll-like receptor signaling pathway, suggesting that miRNAs in the hepatopancreas play a key role in immune responses to pattern recognition receptors. Twelve DEMs were randomly selected for Quantitative Real-time PCR (qRT-PCR). Overall, the expression trends of qRT-PCR were consistent with the sequencing results. These findings corroborate the immunomodulatory function of miRNA in M. rosenbergii against non-O1 V. cholerae infection and provide guidance for the prevention and treatment of related illnesses.

Self-reported symptoms of ocular allergy and its comorbid factors among residents living near a landfill site in Ghana

Residents close to landfill sites may be exposed to long-term emitted toxic compounds that may have effects on their eyes. The aim of this study was to determine the prevalence of symptomatic ocular allergy and its comorbid factors among residents living near a landfill site in Ghana. An exploratory cross-sectional design involving 400 inhabitants living around a landfill site was employed. The prevalence of symptomatic ocular allergy was 59.3%. In a bivariate analysis, comorbid conditions including respiratory disease, coughing, flu, cholera, skin disease, diarrhoea, and hypertension predicted symptomatic ocular allergy. However, only cholera remained a significant predictor of symptomatic ocular allergy in the multivariate analysis. Symptomatic ocular allergy was high among inhabitants around the landfill site in Ghana. While proper design and management of landfills in Ghana is crucial, further longitudinal and clinical studies are required to clinically establish the link between landfill and ocular allergy.

Dracula as Cholera: The Influences of Sligo's Cholera Epidemic of 1832 on Bram Stoker's Novel Dracula (1897)

The paper argues that historic events in the western Irish town of Sligo were more substantial in shaping Bram Stoker's novel Dracula (1897) than previously thought. Biographers of Stoker have credited his mother, Charlotte Thornley Stoker, for influencing her son's gothic imagination during his childhood by sharing tales of the Sligo cholera epidemic she had witnessed in 1832. While Charlotte Stoker's written account of Sligo's epidemic Experiences of the Cholera in Ireland (1873) influenced Bram Stoker, it is argued that as a voracious library researcher he is likely to have cross-referenced it with other historical accounts. Furthermore, by viewing the text of Dracula through the lens of Charlotte Stoker's account and the historical reportage of the epidemic, clear parallels emerge. Ultimately, the striking similarities between Sligo's cholera are marshaled to argue that Count Dracula may be read as the personification of Sligo's cholera.

Environmental Drivers of Vibrio cholerae Abundances in Mobile Bay, Alabama

Vibrio cholerae is the etiological agent of the illness cholera. However, there are non-O1/non-O139 V. cholerae (NOVC) strains that generally lack the toxin gene (ctx) and colonization factors that cause cholera. These NOVC strains are autochthonous members of estuarine environments and a significant cause of seafood-borne gastroenteritis in the United States. The objective of this study was to identify environmental parameters that correlate with NOVC prevalence in oysters, water, and sediment at three ecologically diverse locations in Mobile Bay, AL, including Dog River (DR), Fowl River (FR), and Cedar Point (CP). Oyster, water, and sediment samples were collected twice a month when conditions were favorable for NOVC growth and once a month when they were not. A most probable number (MPN)/real-time PCR assay was used to determine NOVC abundances. Environmental parameters were measured during sampling to determine their relationship, if any, with NOVC at each site. NOVC abundances in oysters at DR, FR, and CP were 0.87, 0.87, and -0.13 log MPN/g, respectively. In water, the median NOVC levels at DR, FR, and CP were 1.18, -0.13, and -0.82 log MPN/mL, and in sediment, the levels were 1.48, 1.87, and -0.03 log MPN/g, respectively. Correlations of NOVC abundances in oyster, water, and sediment samples with environmental parameters were largely site specific. For example, the levels of NOVC in oysters at DR had a positive correlation with temperature but a negative correlation with dissolved oxygen (DO) and nutrient concentrations, NO2-, NO3-, dissolved inorganic nitrogen (DIN), total dissolved nitrogen (TDN), and dissolved inorganic phosphorus (DIP). At FR, however, the levels of NOVC in oysters displayed only a negative correlation with NO2-. When grouping NOVC abundances by temperature, the main driving factor for prevalence, additional correlations with salinity, total cell counts, dissolved organic nitrogen (DON), and dissolved organic carbon (DOC) became evident regardless of the site. IMPORTANCE NOVC can cause gastrointestinal illness in humans, which typically occurs after the consumption of raw or undercooked seafood. Incidence rates of NOVC gastroenteritis have increased during the past decade. In this study, NOVC was enumerated from oysters, sediment, and water collected at three sites in Mobile Bay, with environmental parameters measured concurrently over the course of a year, to identify potential environmental drivers of NOVC abundances. The data from this study, from an area lacking in V. cholerae research, provide a useful baseline for risk analysis of V. cholerae infections. Defining correlations between NOVC and environmental attributes at different sites and temperatures within a dynamic system such as Mobile Bay provides valuable data to better understand the occurrence and proliferation of V. cholerae in the environment.

Development of a smart pH-responsive nano-polymer drug, 2-methoxy-4-vinylphenol conjugate against the intestinal pathogen, Vibrio cholerae

Vibrio cholerae causes cholera, an acute diarrhoeal disease. The virulence in V. cholerae is regulated by the quorum-sensing mechanism and response regulator LuxO positively regulates the expression of virulence determinants adhesion, biofilm formation, and cholera toxin production. Previous in-silico studies revealed that 2-methoxy-4-vinylphenol could bind to the ATP binding site of LuxO and the complex was compact and stable in pHs like intestinal pHs. Here, we have explored the polymeric nano-formulation of 2-methoxy-4-vinylphenol using cellulose acetate phthalate for controlled drug release and their effectiveness in attenuating the expression of V. cholerae virulence. Physico-chemical characterization of the formulation showed particles with a mean size of 91.8 ± 14 nm diameter and surface charge of - 14.7 ± 0.07 mV. The uniform round polymeric nanoparticles formed displayed about 51% burst release of the drug at pH 7 by 3rd h, followed by a controlled linear release in alkaline pH. The polymeric nanoparticles demonstrated a tenfold increase in intestinal membrane permeability ex-vivo. At lower concentrations, the 2-methoxy-4-vinylphenol polymeric nanoparticles were non-cytotoxic to Int 407 cells. In-vitro analysis at pH 6, pH 7, pH 8, and pH 9 revealed that cellulose acetate phthalate-2-methoxy-4-vinylphenol nanoparticles were non-bactericidal at concentrations up to 500 μg/mL. At 31.25 μg/mL, the nanoparticles inhibited about 50% of the biofilm formation of V. cholerae MTCC 3905 and HYR14 strains. At this concentration, the adherence of V. cholerae MTCC 3905 and HYR14 to Int 407 cell lines were also significantly affected. Gene expression analysis revealed that the expression of tcp, qrr, and ct at pH 6, 7, 8, and 9 has reduced. The CAP-2M4VP nanoparticles have demonstrated the potential to effectively reduce the virulence of V. cholerae in-vitro.

Amine Functionalized Gadolinium Oxide Nanoparticles-Based Electrochemical Immunosensor for Cholera

Herein, we report the synthesis and functionalization of gadolinium oxide nanoparticles (Gd₂O₃ NPs) to fabricate a highly efficient immunosensor for the detection of Vibrio cholera toxin (CT). Gd₂O₃ NPs were produced in a straightforward manner utilizing the microwave irradiation technique using a domestic microwave oven. X-ray diffraction, transmission electron microscopy, and spectroscopic techniques were used to characterize the structural and physical aspects of Gd₂O₃ NPs. The Gd₂O₃ NPs were then functionalized with 3-(Aminopropyl) triethoxysilane (APTES) and electrophoretically deposited onto an ITO-coated glass substrate. The anti-CT monoclonal antibodies were covalently attached to the APTES-Gd₂O₃/ITO electrode via EDC-NHS chemistry, followed by bovine serum albumin (BSA). For CT detection, electrochemical response experiments using BSA/anti-CT/APTES-Gd₂O₃/ITO immunoelectrodes were carried out (5-700 ng mL^-1). The immunoelectrode demonstrated an outstanding electrochemical reaction against CT, with a sensitivity of 8.37 mA ng^-1 mL cm^-2 and a detection limit of 1.48 ng mL^-1.

B-Cell Epitope Mapping of the Vibrio cholera Toxins A, B, and P and an ELISA Assay

Oral immunization with the choleric toxin (CT) elicits a high level of protection against its enterotoxin activities and can control cholera in endemic settings. However, the complete B-cell epitope map of the CT that is responsible for protection remains to be clarified. A library of one-hundred, twenty-two 15-mer peptides covering the entire sequence of the three chains of the CT protein (CTP) was prepared by SPOT synthesis. The immunoreactivity of membrane-bound peptides with sera from mice vaccinated with an oral inactivated vaccine (Schankol™) allowed the mapping of continuous B-cell epitopes, topological studies, multi-antigen peptide (MAP) synthesis, and Enzyme-Linked Immunosorbent Assay (ELISA) development. Eighteen IgG epitopes were identified; eight in the CTA, three in the CTB, and seven in the protein P. Three V. cholera specific epitopes, Vc/TxA-3, Vc/TxB-11, and Vc/TxP-16, were synthesized as MAP4 and used to coat ELISA plates in order to screen immunized mouse sera. Sensitivities and specificities of 100% were obtained with the MAP4s of Vc/TxA-3 and Vc/TxB-11. The results revealed a set of peptides whose immunoreactivity reflects the immune response to vaccination. The array of peptide data can be applied to develop improved serological tests in order to detect cholera toxin exposure, as well as next generation vaccines to induce more specific antibodies against the cholera toxin.

Long-term sialidase-specific immune responses after natural infection with cholera: Findings from a longitudinal cohort study in Bangladesh

Background

Immune responses that target sialidase occur following natural cholera and have been associated with protection against cholera. Sialidase is a neuraminidase that facilitates the binding of cholera toxin (CT) to intestinal epithelial cells. Despite this, little is known about age-related sialidase-specific immune responses and the impact of nutritional status and co-infection on sialidase-specific immunity.

Methods

We enrolled 50 culture-confirmed Vibrio cholerae O1 cholera cases presenting to the icddr,b Dhaka hospital with moderate to severe dehydration. We evaluated antibody responses out to 18 months (day 540) following cholera. We assessed immune responses targeting sialidase, lipopolysaccharide (LPS), cholera toxin B subunit (CtxB), and vibriocidal responses. We also explored the association of sialidase-specific immune responses to nutritional parameters and parasitic co-infection of cases.

Results

This longitudinal cohort study showed age-dependent differences in anti-sialidase immune response after natural cholera infection. Adult patients developed plasma anti-sialidase IgA and IgG responses after acute infection (P<0.05), which gradually decreased from day 30 on. In children, no significant anti-sialidase IgA, IgM, and IgG response was seen with the exception of a late IgG response at study day 540 (p=0.05 compared to adults). There was a correlation between anti-sialidase IgA with vibriocidal titers, as well as anti-sialidase IgA and IgG with anti-LPS and anti-CtxB antibody responses in adult patients, whereas in children, a significant positive correlation was seen only between anti-sialidase IgA and CtxB IgA responses. Stunted children showed significantly lower anti-sialidase IgA, IgG, and IgM antibody responses and higher LPS IgG and IgM antibody responses than healthy children. The anti-sialidase IgA and IgG responses were significantly higher in cases with concomitant parasitic infection.

Conclusion

Our data suggest that cholera patients develop age-distinct systemic and mucosal immune responses against sialidase. The stunted children have a lower anti-sialidase antibody response which may be associated with gut enteropathy and the neuraminidase plays an important role in augmented immune response in cholera patients infected with parasites.

Pasteurella multocida toxin - lessons learned from a mitogenic toxin

The gram-negative, zoonotic bacterium Pasteurella multocida was discovered in 1880 and found to be the causative pathogen of fowl cholera. Pasteurella-related diseases can be found in domestic and wild life animals such as buffalo, sheep, goat, deer and antelope, cats, dogs and tigers and cause hemorrhagic septicemia in cattle, rhinitis or pneumonia in rabbits or fowl cholera in poultry and birds. Pasteurella multocida does not play a major role in the immune-competent human host, but can be found after animal bites or in people with close contact to animals. Toxigenic strains are most commonly found in pigs and express a phage-encoded 146 kDa protein, the Pasteurella multocida toxin (PMT). Toxin-expressing strains cause atrophic rhinitis where nasal turbinate bones are destroyed through the inhibition of bone building osteoblasts and the activation of bone resorbing osteoclasts. After its uptake through receptor-mediated endocytosis, PMT specifically targets the alpha subunit of several heterotrimeric G proteins and constitutively activates them through deamidation of a glutamine residue to glutamate in the alpha subunit. This results in cytoskeletal rearrangement, proliferation, differentiation and survival of cells. Because of the toxin's mitogenic effects, it was suggested that it might have carcinogenic properties, however, no link between Pasteurella infections and cell transformation could be established, neither in tissue culture models nor through epidemiological data. In the recent years it was shown that the toxin not only affects bone, but also the heart as well as basically all cells of innate and adaptive immunity. During the last decade the focus of research shifted from signal transduction processes to understanding how the bacteria might benefit from a bone-destroying toxin. The primary function of PMT seems to be the modulation of immune cell activation which at the same time creates an environment permissive for osteoclast formation. While the disease is restricted to pigs, the implications of the findings from PMT research can be used to explore human diseases and have a high translational potential. In this review our current knowledge will be summarized and it will be discussed what can be learned from using PMT as a tool to understand human pathologies.

How did primary health care in Beira experience Cyclone Idai?

Beira, the biggest city of Mozambique's Sofala province, was struck by Cyclone Idai on 14 March 2019, with devastating impacts. The floods along with the cyclone destroyed road infrastructure and health facilities and disrupted primary health care (PHC) service delivery. In addition, destruction of farmland and food stocks resulted in malnutrition; the abundance of water fostered the reproduction of mosquitos, exacerbating the burden of malaria; and problems with water and sanitation led to epidemics of cholera. The exact role and contribution of human-induced climate change is very difficult to quantify, but there is little doubt that climate change is driving more frequent and severe cyclones, such as Idai. Considering the current climatic changes, it is expected that climate hotspots such as Beira will only experience more frequent extreme weather events. In these settings, with high risks but low adaptive capacity, dedicated efforts are required to strengthen PHC with a focus on preparedness for disasters. This should entail community awareness and education, strengthening infrastructure and service provision, as well as collaboration with important stakeholders across other sectors.Contribution: Using a case study approach, this article contributes climate resilient PHC for better preparedness to service continuity.

Abiotic factors modulate interspecies competition mediated by the type VI secretion system effectors in Vibrio cholerae

Vibrio cholerae, the etiological pathogen of cholera, employs its type VI secretion system (T6SS) as an effective weapon to survive in highly competitive communities. Antibacterial and anti-eukaryotic functions of the T6SS depend on its secreted effectors that target multiple cellular processes. However, the mechanisms that account for effector diversity and different effectiveness during interspecies competition remain elusive. Here we report that environmental cations and temperature play a key role in dictating cellular response and effector effectiveness during interspecies competition mediated by the T6SS of V. cholerae. We found that V. cholerae could employ its cell-wall-targeting effector TseH to outcompete the otherwise resistant Escherichia coli and the V. cholerae immunity deletion mutant ∆tsiH when Mg²⁺ or Ca²⁺ was supplemented. Transcriptome and genetic analyses demonstrate that the metal-sensing PhoPQ two-component system is important for Mg²⁺-dependent sensitivity. Competition analysis in infant mice shows that TseH was active under in vivo conditions. Using a panel of V. cholerae single-effector active mutants, we further show that E. coli also exhibited variable susceptibilities to other T6SS effectors depending on cations and temperatures, respectively. Lastly, V. cholerae effector VasX could sensitize Pseudomonas aeruginosa to its intrinsically resistant antibiotic irgasan in a temperature-dependent manner. Collectively, these findings suggest that abiotic factors, that V. cholerae frequently encounters in natural and host environments, could modulate cellular responses and dictate the competitive fitness conferred by the T6SS effectors in complex multispecies communities.

Mucosal-Associated Invariant T (MAIT) cells are highly activated in duodenal tissue of humans with Vibrio cholerae O1 infection: A preliminary report

Mucosal-associated invariant T (MAIT) cells are unconventional T lymphocytes with a semi-conserved TCRα, activated by the presentation of vitamin B metabolites by the MHC-I related protein, MR1, and with diverse innate and adaptive effector functions. The role of MAIT cells in acute intestinal infections, especially at the mucosal level, is not well known. Here, we analyzed the presence and phenotype of MAIT cells in duodenal biopsies and paired peripheral blood samples, in patients during and after culture-confirmed Vibrio cholerae O1 infection. Immunohistochemical staining of duodenal biopsies from cholera patients (n = 5, median age 32 years, range 26-44, 1 female) identified MAIT cells in the lamina propria of the crypts, but not the villi. By flow cytometry (n = 10, median age 31 years, range 23-36, 1 female), we showed that duodenal MAIT cells are more activated than peripheral MAIT cells (p < 0.01 across time points), although there were no significant differences between duodenal MAIT cells at day 2 and day 30. We found fecal markers of intestinal permeability and inflammation to be correlated with the loss of duodenal (but not peripheral) MAIT cells, and single-cell sequencing revealed differing T cell receptor usage between the duodenal and peripheral blood MAIT cells. In this preliminary report limited by a small sample size, we show that MAIT cells are present in the lamina propria of the duodenum during V. cholerae infection, and more activated than those in the blood. Future work into the trafficking and tissue-resident function of MAIT cells is warranted.

Microbiota-Associated Biofilm Regulation Leads to Vibrio cholerae Resistance Against Intestinal Environmental Stress

The commensal microbes of the gut microbiota make important contributions to host defense against gastrointestinal pathogens, including Vibrio cholerae, the etiologic agent of cholera. As interindividual microbiota variation drives individual differences in infection susceptibility, we examined both host and V. cholerae gene expression during infection of suckling mice transplanted with different model human commensal communities, including an infection-susceptible configuration representing communities damaged by recurrent diarrhea and malnutrition in cholera endemic areas and a representative infection-resistant microbiota characteristic of healthy individuals. In comparison to colonization of animals with resistant microbiota, animals bearing susceptible microbiota challenged with V. cholerae downregulate genes associated with generation of reactive oxygen/nitrogen stress, while V. cholerae in these animals upregulates biofilm-associated genes. We show that V. cholerae in susceptible microbe infection contexts are more resistant to oxidative stress and inhibitory bile metabolites generated by the action of commensal microbes and that both phenotypes are dependent on biofilm-associated genes, including vpsL. We also show that susceptible and infection-resistant microbes drive different bile acid compositions in vivo by the action of bile salt hydrolase enzymes. Taken together, these findings provide a better understanding of how the microbiota uses multiple mechanisms to modulate the infection-associated host environment encountered by V. cholerae, leading to commensal-dependent differences in infection susceptibility.

Genetic and mutational analysis of virulence traits and their modulation in an environmental toxigenic Vibrio cholerae non-O1/non-O139 strain, VCE232

Vibrio cholerae O1 and O139 isolates deploy cholera toxin (CT) and toxin-coregulated pilus (TCP) to cause the diarrhoeal disease cholera. The ctxAB and tcpA genes encoding CT and TCP are part of two acquired genetic elements, the CTX phage and Vibrio pathogenicity island-1 (VPI-1), respectively. ToxR and ToxT proteins are the key regulators of virulence genes of V. cholerae O1 and O139. V. cholerae isolates belonging to serogroups other than O1/O139, called non-O1/non-O139, are usually devoid of virulence-related elements and are non-pathogenic. Here, we have analysed the available whole genome sequence of an environmental toxigenic V. cholerae non-O1/non-O139 strain, VCE232, carrying the CTX phage and VPI-1. Extensive bioinformatics and phylogenetic analyses indicated high similarity of the VCE232 genome sequence with the genome of V. cholerae O1 strains, including organization of the VPI-1 locus, ctxAB, tcpA and toxT genes, and promoters. We established that the VCE232 strain produces an optimal amount of CT at 30 °C under AKI conditions. To investigate the role of ToxT and ToxR in the regulation of virulence factors, we constructed ΔtoxT, ΔtoxR and ΔtoxTΔtoxR deletion mutants of VCE232. Extensive genetic analyses of these mutants indicated that the toxT and toxR genes of VCE232 are crucial for CT and TCP production. However, unlike O1 isolates, the presence of either toxT or toxR gene is sufficient for optimal CT production in VCE232. In addition, the VCE232 ΔtoxR mutant showed differential regulation of the major outer membrane proteins, OmpT and OmpU. This is the first attempt to explore the regulation of expression of major virulence genes and regulators in an environmental toxigenic V. cholerae non-O1/non-O139 strain.

Phenotypic and genotypic characterization of antimicrobial resistance in clinical isolates of Vibrio cholerae over a decade (2002-2016)

PURPOSE

Emergence and spread of resistance among Vibrio cholerae have become a global public health problem. In India, no consolidated data is available on antimicrobial susceptibility patterns and antibiotic resistance genes.

METHODS

A total of 110 representative isolates obtained over a period of 14 years were included. Antimicrobial susceptibility was tested by disc diffusion and micro broth dilution. Presence of 13 antimicrobial resistance genes was ascertained by using PCR.

RESULTS

Antimicrobial resistance fluctuated for most of the antibiotics. Resistance to cotrimoxazole in our study was 92.72% and the SXT element was present in all isolates. Resistance to nalidixic acid, tetracycline, and cefotaxime was found to be 98.18%, 7.27%, and 10.9% respectively. Resistance to ampicillin saw a fluctuating trend with a recent fall. Resistance to ciprofloxacin and azithromycin was 12.72% and 29% by MIC. bla_TEM was the most common ESBL gene (94.5%). Other were bla_CMY (26.36%) and bla_NDM (2.7%). We report bla_CTX-M-15 and bla_OXA-48 and ermB for the first time in the world. Newer antimicrobials like prulifloxacin and rifaximin were tested for the first time from India.

CONCLUSIONS

Our study has shown very high levels of resistance to older antibiotics and the emergence of resistance to some of the newer classes of antibiotics. There is an urgent need for increased surveillance studies, rational use of the antimicrobials and preventive measures to control the disease.

Temperature and risk of infectious diarrhea: a systematic review and meta-analysis

Infectious diarrhea (ID) is an intestinal infectious disease including cholera, typhoid and paratyphoid fever, bacterial and amebic dysentery, and other infectious diarrhea. There are many studies that have explored the relationship between ambient temperature and the spread of infectious diarrhea, but the results are inconsistent. It is necessary to systematically evaluate the impact of temperature on the incidence of ID. This study was based on the PRISMA statement to report this systematic review. We conducted literature searches from CNKI, VIP databases, CBM, PubMed, Web of Science, Cochrane Library, and other databases. The number registered in PROSPERO is CRD42021225472. After searching a total of 4915 articles in the database and references, 27 studies were included. The number of people involved exceeded 7.07 million. The overall result demonstrated when the temperature rises, the risk of infectious diarrhea increases significantly (RR_cumulative=1.42, 95%CI: 1.07-1.88, RR_single-day=1.08, 95%CI: 1.03-1.14). Subgroup analysis found the effect of temperature on the bacillary dysentery group (RR_cumulative=1.85, 95%CI: 1.48-2.30) and unclassified diarrhea groups (RR_cumulative=1.18, 95%CI: 0.59-2.34). The result of the single-day effect subgroup analysis was similar to the result of the cumulative effect. And the sensitivity analysis proved that the results were robust. This systematic review and meta-analysis support that temperature will increase the risk of ID, which is helpful for ID prediction and early warning in the future.

[A young woman with severe dehydration]

A 28-year-old female presented with severe dehydration due to acute diarrhea and vomiting, which she developed after returning from a vacation in Togo. Her stool was watery, with flecks of mucous, also referred to as "rice-water" stool, which is typical for cholera and can amount to 1000 cc/hour. The infection was confirmedby stool culture.

Environmental reservoirs of Vibrio cholerae serogroups in the flowing freshwater environs from the tribal areas of Odisha, Eastern India

The environmental reservoirs of different serogroups of Vibrio cholerae causing cholera in the flowing freshwater bodies of the tribal areas of Odisha are not known. So the present study was conducted from June 2017 to March 2020 to find out the environmental reservoirs of V. cholerae serogroups in the water and plankton samples collected from the river, nala, stream and chua from Rayagada district. Similarly, rectal swabs were collected from diarrhoea patients and correlation was established among the V. cholerae strains isolated from diarrhoea patients and environmental V. cholerae isolates through routine culture, different multiplex PCR assays and pulse field gel electrophoresis (PFGE) analysis using standard techniques. The multiplex PCR assays on biotypes and different toxic genes exhibited similar correlation between the clinical and water isolates, which was further strengthened by PFGE analysis. The planktonic DNA was positive for ctxA gene which established that the environmental water bodies were the reservoirs for virulence genes of V. cholerae serogroups. The detection of environmental reservoirs of V. cholerae serogroups in temporarily stagnant condition of water; partially encircled by stones, and near the bank of the river, nala and stream were the reservoirs which is a rare report from Odisha, India and Globe.

Laboratory efficacy of surface disinfection using chlorine against Vibrio cholerae

Disinfecting surfaces with chlorine is commonly conducted in cholera outbreaks to prevent ongoing fomite-based transmission, yet evidence gaps have led to contradictory guidance. In this study, we tested the efficacy of spraying and wiping chlorine on five representatives non-porous and five porous surfaces to remove Vibrio cholerae. In total, 120 disinfection tests were run in replicate on carriers inoculated with 1.02 × 10⁷-1.73 × 10⁸ V. cholerae CFU/cm². Surfaces disinfected by spraying 0.2% chlorine had >3 log reduction value (LRV) on 7/10 and 9/10 surfaces at 1 and 10 min, respectively; and 2.0% chlorine on 9/10 and 10/10 surfaces at 1 and 10 min, respectively. Surfaces disinfected by wiping 0.2% chlorine had >3 LRV on 3/10 and 7/10 surfaces at 1 and 10 min, respectively; and 2.0% chlorine on 8/10 surfaces at 1 and 10 min. We found no significant differences between chlorine types (p < 0.05), higher reductions with spraying compared to wiping (p = 0.001), and lower reductions on porous compared to non-porous surfaces (p = 0.006 spraying and p < 0.001 wiping). Our results support using 0.2% chlorine sprayed on all surfaces, or wiped on most non-heavily soiled surfaces, and a 2.0% concentration on contaminated porous surfaces; and emphasize surfaces must be visibly wetted to achieve disinfection.

How climate change can affect cholera incidence and prevalence? A systematic review

Although the number of cholera infection decreased universally, climate change can potentially affect both incidence and prevalence rates of disease in endemic regions. There is considerable consistent evidence, explaining the associations between cholera and climatic variables. However, it is essentially required to compare and interpret these relationships globally. The aim of the present study was to carry out a systematic review in order to identify and appraise the literature concerning the relationship between nonanthropogenic climatic variabilities such as extreme weather- and ocean-related variables and cholera infection rates. The systematic literature review of studies was conducted by using determined search terms via four major electronic databases (PubMed, Web of Science, Embase, and Scopus) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. This search focused on published articles in English-language up to December 31, 2018. A total of 43 full-text studies that met our criteria have been identified and included in our analysis. The reviewed studies demonstrated that cholera incidence is highly attributed to climatic variables, especially rainfall, temperature, sea surface temperature (SST) and El Niño Southern Oscillation (ENSO). The association between cholera incidence and climatic variables has been investigated by a variety of data analysis methodologies, most commonly time series analysis, generalized linear model (GLM), regression analysis, and spatial/GIS. The results of this study assist the policy-makers who provide the efforts for planning and prevention actions in the face of changing global climatic variables.

Solar inactivated Vibrio cholerae induces maturation of JAWS II dendritic cell line in vitro

Solar disinfection (SODIS) has been shown to reduce the risk associated with the contraction of water borne diseases such as cholera. However, little or no research has been undertaken in exploring the role played by the immune system following the consumption of solar inactivated water pathogens. This study investigated the potential for solar inactivated Vibrio cholerae to induce the maturation of dendritic cells in vitro. Dendritic cells are professional antigen presenting cells found in mammals. However, only in their mature form are dendritic cells able to play their role towards a long lasting immune response. Three strains of V. cholerae were solar irradiated for 7 hours. Thereafter, the solar irradiated, non-solar irradiated, phosphate buffered saline prepared and heat/chemically inactivated cultures of V. cholerae as well as lipopolysaccharide and cholerae toxin-β subunit were used to stimulate immature dendritic cells. After 48 hours, the dendritic cells were assessed for the expression of CD54, CD80, CD83, CD86, MHC-I and MHC-II cell surface markers. Results show that solar inactivated V. cholerae was able to induce maturation of the dendritic cells in vitro. These findings suggest that there may be an immunological benefit in consuming SODIS treated water.

Impact of Annual Bacterial Epizootics on Albatross Population on a Remote Island

The reduced species richness typical of oceanic islands provides an interesting environmental setup to examine in natura the epidemiological dynamics of infectious agents with potential implications for public health and/or conservation. On Amsterdam Island (Indian Ocean), recurrent die-offs of Indian yellow-nosed albatross (Thalassarche carteri) nestlings have been attributed to avian cholera, caused by the bacterium Pasteurella multocida. In order to help implementing efficient measures for the control of this disease, it is critical to better understand the local epidemiology of P. multocida and to examine its inter- and intra-annual infection dynamics. We evaluated the infection status of 264 yellow-nosed albatrosses over four successive breeding seasons using a real-time PCR targeting P. multocida DNA from cloacal swabs. Infection prevalence patterns revealed an intense circulation of P. multocida throughout the survey, with a steady but variable increase in infection prevalence within each breeding season. These epizootics were associated with massive nestling dies-offs, inducing very low fledging successes (≤ 20%). These results suggest important variations in the transmission dynamics of this pathogen. These findings and the developed PCR protocol have direct applications to guide future research and refine conservation plans aiming at controlling the disease.

Tuberculosis, Cholera, Anthrax: Dreadful Culprits

Dreadful culprits from the minuscule world, indeed, but … what about poverty, war, and terrorism in the macroscopic nowadays world?

Poverty and health among CDC plantation labourers in Cameroon: Perceptions, challenges and coping strategies

Creating better access to good quality healthcare for the poor is a major challenge to development. In this study, we examined inter-linkages between poverty and disease, referred to as poverty-related diseases (PRDs), by investigating how Cameroon Development Corporation (CDC) camp dwellers respond to diseases that adversely affect their health and wellbeing. Living in plantation camps is associated with poverty, overcrowding, poor sanitation and the rapid spread of diseases. In a survey of 237 CDC camp dwellers in Cameroon, we used the health belief model to understand the drivers (perceived threats, benefits and cues for treatment seeking) of reported responses. Using logistic regression analysis, we looked for trends in people’s response to malaria. We calculated the odds ratio of factors shown to have an influence on people’s health, such as food, water, sanitation challenges and seeking formal healthcare for malaria. Malaria (40.3%), cholera (20.8%) and diarrhoea (17.7%) were the major PRDs perceived by camp dwellers. We found a strong link between what respondents perceived as PRDS and hygiene conditions. Poverty for our respondents was more about living in poor hygiene conditions than lack of money. Respondents perceived health challenges as stemming from their immediate living environment. Moreover, people employed self-medication and other informal health practices to seek healthcare. Interestingly, even though respondents reported using formal healthcare services as a general response to illness (84%), almost 90% stated that, in the case of malaria, they would use informal healthcare services. Our study recommends that efforts to curb the devastating effects of PRDs should have a strong focus on perceptions (i.e. include diseases that people living in conditions of poverty perceive as PRDs) and on hygiene practices, emphasising how they can be improved. By providing insights into the inter-linkages between poverty and disease, our study offers relevant guidance for potentially successful health promotion interventions.

Poverty is a condition that increases disease risks and presents severe health challenges. The negative impact of poverty on health is well understood, but much less is known about how people living in poor conditions themselves perceive health challenges and how they try to overcome these challenges. We studied a group of Cameroon Development Corporation (CDC) plantation workers, living in housing provided by the company, known as camps. Living conditions in plantation camps are characterised by small and very basic housing, shared toilet facilities and overall poor sanitation. In the camps, water sources were public taps found in strategic areas. During water cuts, camp dwellers used streams as their water sources. Water was treated at CDC management level. We questioned 237 labourers (or dependants) on matters related to their health. Malaria, cholera and diarrhoea were reported as the main diseases that they associated with poverty. Our results also show that the labourers associated poverty primarily with the poor state of their living conditions rather than with not having money. Even though CDC offered free healthcare, camp dwellers relied on self-treatment and unofficial medication, especially for malaria for which almost 90% of the workers did not use the free services. Therefore, for interventions to be successful, they should include people’s perceptions and focus on improving hygiene conditions.

Vibrio cholerae ensures function of host proteins required for virulence through consumption of luminal methionine sulfoxide

Vibrio cholerae is a diarrheal pathogen that induces accumulation of lipid droplets in enterocytes, leading to lethal infection of the model host Drosophila melanogaster. Through untargeted lipidomics, we provide evidence that this process is the product of a host phospholipid degradation cascade that induces lipid droplet coalescence in enterocytes. This infection-induced cascade is inhibited by mutation of the V. cholerae glycine cleavage system due to intestinal accumulation of methionine sulfoxide (MetO), and both dietary supplementation with MetO and enterocyte knock-down of host methionine sulfoxide reductase A (MsrA) yield increased resistance to infection. MsrA converts both free and protein-associated MetO to methionine. These findings support a model in which dietary MetO competitively inhibits repair of host proteins by MsrA. Bacterial virulence strategies depend on functional host proteins. We propose a novel virulence paradigm in which an intestinal pathogen ensures the repair of host proteins essential for pathogenesis through consumption of dietary MetO.

[Antibiotic resistance and molecular characterization of Vibrio cholera strains isolated from an outbreak of cholera epidemic in Jiangsu province]

OBJECTIVE

To assess the antibiotic resistance and molecular characterization of cholera strains and to provide basis for clinical treatment and prevention of cholera.

METHODS

4 stains isolated from an outbreak of cholera epidemic in Huai'an City in Jiangsu province in September 2010 were characterized using antibiotic susceptibility, biotype analysis, virluence genes detection, ctxB gene sequencing, and PFGE analysis.

RESULTS

The 4 strains were all resistant to sulphamethoxazole/trimethoprim, erythromycin, streptomycin. High drug susceptibility of the samples was found to 6 kinds of antibiotics such as amikacin, norfloxacin, ciprofloxacin, gentamicin, chloramphenicol, ampicillin. The isolates expressed phenotypic traits of both serogroup O1 ogawa and El Tor and carried 9 kinds of virulence genes, ctxA, ace, zot, toxR, tcpI, ompU, rtxC, tcpA, and hlyA gene. They were also identified as harboring the classical ctxB genotype based on amino acid residue substitutions. The PFGE profiles of NotI showed a single banding pattern, while SfiI's was 2 banding patterns.

CONCLUSION

The bacterium type of Vibrio cholerae causing the epidemic outbreak of cholera belonged to the atypical EL Tor variant which was also identified as toxicogenic strain. The mapping of the strains prompted that there should be the common contamination source. Drug sensitivity test can guide the clinical drug use, in order to reduce the emergence of resistant strains.