scholarly journals A Review on Diagnostic Methods for the Identification of Vibrio cholerae

2020 ◽  
pp. 136-164
Author(s):  
Tarh, Jacqueline Ebob
Keyword(s):  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Variable Number Tandem Repeat ◽  
Simultaneous Detection ◽  
Diagnostic Methods ◽  
Cholerae Strain ◽  
Low Resource Settings ◽  
Remote Areas ◽  
Low Resource ◽  
Life Threatening

The severe diarrheal disease Cholera, has gained public health importance because of its life-threatening effect. The detection of the causative agent of this disease (Vibrio cholerae (V.  Cholerae) O1 or O139) from a specimen (stool, vomitus of food sample) remains a major concern in the world today. Phenotypic finger printing (the conventional methods) of the toxigenic V. cholerae strain, remains the gold standard for the laboratory diagnosis of cholera; especially during cholera epidemic outbreaks. Detection around the remote areas which are usually rampaged by these outbreaks is usually difficult due to lack of required diagnostic facilities in small laboratories. However, the use of phenotypic approaches have some major setbacks as they are usually labor-intensive and time consuming. This delays treatment commencement especially in life threatening cases.To alleviate these setbacks, rapid molecular typing techniques involving the Polymerase chain reaction (PCR) amplification, hybridization methods, Pulsed Field Gel Electrophoresis (PFGE), Multilocus Sequence Typing (MLST), Multiple-Locus Variable Number Tandem Repeat Analysis (MVLA), Fluorescent Amplified Fragment Length Polymorphism (FAFLP),  Whole Genome Sequencing (WGS) etc. represent promising tools for early detection of the pathogen V. cholerae O1/O139 even in remote areas where laboratory resources are poor. Immunoassay-based techniques like enzyme-linked immune-sorbent assay (ELISA), coagglutination, immunofluorescence, and quartz crystal microbalance (QCM), are capital/labour intensive and expensive for low resource settings. Rapid diagnostic tests based on immune-chromatography principle have also been developed for simultaneous detection of V. choleraesero groups O1 and O139. These test kits are easy to use, transport, and fast. All these methods enable the subtyping of unrelated bacterial strains and they all operate with different accuracies, discriminatory ability, and reproducibility. This review sought to address some of the methods used in diagnosing the disease cholera, with the objective of identifying the best and easiest of the methods that can help to curb the cholera problem (deaths) often encountered, especially in low resource settings in the developing countries (Nigeria inclusive).

scholarly journals Derivation of the first clinical diagnostic models for dehydration severity in patients over five years with acute diarrhea

2021 ◽  
Vol 15 (3) ◽  
pp. e0009266
Author(s):  
Adam C. Levine ◽  
Meagan A. Barry ◽  
Monique Gainey ◽  
Sabiha Nasrin ◽  
Kexin Qu ◽  
...  
Keyword(s):  
Acute Diarrhea ◽  
Diarrheal Disease ◽  
Characteristic Curve ◽  
World Health ◽  
Simplified Model ◽  
Full Model ◽  
Low Resource Settings ◽  
Low Resource ◽  
Clinical Diagnostic ◽  
Diagnostic Models

Diarrheal diseases lead to an estimated 1.3 million deaths each year, with the majority of those deaths occurring in patients over five years of age. As the severity of diarrheal disease can vary widely, accurately assessing dehydration status remains the most critical step in acute diarrhea management. The objective of this study is to empirically derive clinical diagnostic models for assessing dehydration severity in patients over five years with acute diarrhea in low resource settings. We enrolled a random sample of patients over five years with acute diarrhea presenting to the icddr,b Dhaka Hospital. Two blinded nurses independently assessed patients for symptoms/signs of dehydration on arrival. Afterward, consecutive weights were obtained to determine the percent weight change with rehydration, our criterion standard for dehydration severity. Full and simplified ordinal logistic regression models were derived to predict the outcome of none (<3%), some (3–9%), or severe (>9%) dehydration. The reliability and accuracy of each model were assessed. Bootstrapping was used to correct for over-optimism and compare each model’s performance to the current World Health Organization (WHO) algorithm. 2,172 patients were enrolled, of which 2,139 (98.5%) had complete data for analysis. The Inter-Class Correlation Coefficient (reliability) was 0.90 (95% CI = 0.87, 0.91) for the full model and 0.82 (95% CI = 0.77, 0.86) for the simplified model. The area under the Receiver-Operator Characteristic curve (accuracy) for severe dehydration was 0.79 (95% CI: 0.76–0.82) for the full model and 0.73 (95% CI: 0.70, 0.76) for the simplified model. The accuracy for both the full and simplified models were significantly better than the WHO algorithm (p<0.001). This is the first study to empirically derive clinical diagnostic models for dehydration severity in patients over five years. Once prospectively validated, the models may improve management of patients with acute diarrhea in low resource settings.

scholarly journals The Sodium-Driven Flagellar Motor Controls Exopolysaccharide Expression in Vibrio cholerae

2004 ◽  
Vol 186 (15) ◽  
pp. 4864-4874 ◽  
Author(s):  
Crystal M. Lauriano ◽  
Chandradipa Ghosh ◽  
Nidia E. Correa ◽  
Karl E. Klose
Keyword(s):  
Vibrio Cholerae ◽  
Gene Transcription ◽  
Biofilm Formation ◽  
Diarrheal Disease ◽  
Response Regulator ◽  
Gene Clusters ◽  
Signaling Cascade ◽  
Genes Encoding ◽  
Life Threatening

ABSTRACT Vibrio cholerae causes the life-threatening diarrheal disease cholera. This organism persists in aquatic environments in areas of endemicity, and it is believed that the ability of the bacteria to form biofilms in the environment contributes to their persistence. Expression of an exopolysaccharide (EPS), encoded by two vps gene clusters, is essential for biofilm formation and causes a rugose colonial phenotype. We previously reported that the lack of a flagellum induces V. cholerae EPS expression. To uncover the signaling pathway that links the lack of a flagellum to EPS expression, we introduced into a rugose flaA strain second-site mutations that would cause reversion back to the smooth phenotype. Interestingly, mutation of the genes encoding the sodium-driven motor (mot) in a nonflagellated strain reduces EPS expression, biofilm formation, and vps gene transcription, as does the addition of phenamil, which specifically inhibits the sodium-driven motor. Mutation of vpsR, which encodes a response regulator, also reduces EPS expression, biofilm formation, and vps gene transcription in nonflagellated cells. Complementation of a vpsR strain with a constitutive vpsR allele likely to mimic the phosphorylated state (D59E) restores EPS expression and biofilm formation, while complementation with an allele predicted to remain unphosphorylated (D59A) does not. Our results demonstrate the involvement of the sodium-driven motor and suggest the involvement of phospho-VpsR in the signaling cascade that induces EPS expression. A nonflagellated strain expressing EPS is defective for intestinal colonization in the suckling mouse model of cholera and expresses reduced amounts of cholera toxin and toxin-coregulated pili in vitro. Wild-type levels of virulence factor expression and colonization could be restored by a second mutation within the vps gene cluster that eliminated EPS biosynthesis. These results demonstrate a complex relationship between the flagellum-dependent EPS signaling cascade and virulence.

scholarly journals Characterization of the Immune Response to Vibrio cholerae Infection in a Natural Host Model

2021 ◽  
Vol 11 ◽  
Author(s):  
Dustin A. Farr ◽  
Dhrubajyoti Nag ◽  
Jeffrey H. Withey
Keyword(s):  
Immune Response ◽  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Natural Host ◽  
Zebrafish Model ◽  
Mucin Production ◽  
Immunological Markers ◽  
Contaminated Food ◽  
Life Threatening ◽  
El Tor

The gram-negative bacterium Vibrio cholerae causes the life-threatening diarrheal disease cholera, which is spread through the ingestion of contaminated food or water. Cholera epidemics occur largely in developing countries that lack proper infrastructure to treat sewage and provide clean water. Numerous vertebrate fish species have been found to be natural V. cholerae hosts. Based on these findings, zebrafish (Danio rerio) have been developed as a natural host model for V. cholerae. Diarrheal symptoms similar to those seen in humans are seen in zebrafish as early as 6 hours after exposure. Our understanding of basic zebrafish immunology is currently rudimentary, and no research has been done to date exploring the immune response of zebrafish to V. cholerae infection. In the present study, zebrafish were infected with either pandemic El Tor or non-pandemic, environmental V. cholerae strains and select immunological markers were assessed to determine cellular immunity and humoral immunity. Significant increases in the gene expression of two transcription factors, T-bet and GATA3, were observed in response to infection with both V. cholerae strains, as were levels of mucosal related antibodies. Additionally, the cytokine IL-13 was shown to be significantly elevated and paralleled the mucin output in zebrafish excretions, strengthening our knowledge of IL-13 induced mucin production in cholera. The data presented here further solidify the relevancy of the zebrafish model in studying V. cholerae, as well as expanding its utility in the field of cholera immunology.

scholarly journals Mr.Vc: a database of microarray and RNA-seq of Vibrio cholerae

Database ◽  
2019 ◽  
Vol 2019 ◽  
Author(s):  
Zhiyuan Zhang ◽  
Guozhong Chen ◽  
Jun Hu ◽  
Wajid Hussain ◽  
Fenxia Fan ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Gene Annotation ◽  
Relevant Information ◽  
Differentially Expressed ◽  
Data Repository ◽  
Rna Seq ◽  
Experimental Conditions ◽  
Life Threatening ◽  
Infectious Cycle

AbstractGram-negative bacterium Vibrio cholerae is the causative agent of cholera, a life-threatening diarrheal disease. During its infectious cycle, V. cholerae routinely switches niches between aquatic environment and host gastrointestinal tract, in which V. cholerae modulates its transcriptome pattern accordingly for better survival and proliferation. A comprehensive resource for V. cholerae transcriptome will be helpful for cholera research, including prevention, diagnosis and intervention strategies. In this study, we constructed a microarray and RNA-seq database of V. cholerae (Mr.Vc), containing gene transcriptional expression data of 145 experimental conditions of V. cholerae from various sources, covering 25 937 entries of differentially expressed genes. In addition, we collected relevant information including gene annotation, operons they may belong to and possible interaction partners of their protein products. With Mr.Vc, users can easily find transcriptome data they are interested in, such as the experimental conditions in which a gene of interest was differentially expressed in, or all genes that were differentially expressed in an experimental condition. We believe that Mr.Vc database is a comprehensive data repository dedicated to V. cholerae and could be a useful resource for all researchers in related fields. Mr.Vc is available for free at http://bioinfo.life.hust.edu.cn/mrvc.

An Accurate and Rapid Color-Based Point-of-Care Assay for the Detection of Severe Anemia in Low Resource Settings

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 688-688
Author(s):  
Patrick T. McGann ◽  
Erika Tyburski ◽  
Vysolela de Oliveira ◽  
Brigida Santos ◽  
Russell E. Ware ◽  
...  
Keyword(s):  
Diagnostic Tool ◽  
Point Of Care ◽  
Hemoglobin Concentration ◽  
Capillary Blood ◽  
Severe Anemia ◽  
Low Resource Settings ◽  
Low Resource ◽  
Color Scale ◽  
Hematology Analyzer ◽  
Life Threatening

Abstract Background: Severe anemia is a leading cause of morbidity and mortality among children in low-resource countries, particulalrly in sub-Saharan Africa, where malaria is endemic and sickle cell disease is prevalent. In many low-resource regions, particularly more remote areas, laboratory diagnostics are not always readily available. The utility of available equipment can be limited by lack of technical expertise, maintenance, and trained personnel, as well as lack of affordable reagents and reliable power. In a setting where severe, life-threatening anemia is common, it is critical for providers to have access to a rapid and accurate diagnostic tool to determine which patients need acute evaluation and treatment. A simple, rapid, accurate, and disposable point-of-care assay (AnemoCheck¨) has recently been tested and published(Tyburski et al. JCI 2014, in press), Hemoglobin concentration is measured by assessing the color of a chemical solution containing hydrogen peroxide and 3,3',5,5'-tetramethylbenzidine, after mixing with 10μL blood. The AnemoCheck assay is self-contained and does not require electricity, complicated sensors, or additional equipment. The color scale of the original assay correlated well with mild anemia (Hb 9-13 g/dL) but was not designed to discriminate lower hemoglobin concentrations. Accordingly, the test was modified to allow the color scale to detect more severe anemia (Hb 2.5-9.1 g/dL), but needs to be tested in a real-world setting where severe anemia is prevalent. Methods: The primary objective of this study was to determine whether AnemoCheck tests could measure hemoglobin concentrations at least as accurately as currently used standard laboratory techniques in low resource settings where severe anemia is common. The study was performed in the sickle cell clinic at Hospital Pedi‡trico David Bernardino, a large, public pediatric hospital in Luanda, Angola. After receiving informed consent from a parent or guardian, capillary blood was collected by fingerstick as per routine to measure hemoglobin using a BioSystems BTS-350 Hemoglobin Analyzer. A small sample of capillary blood was also collected for the AnemoCheck assay using a 10μL end-to-end capillary tube via capillary action (Sanguis Counting, Germany). Venous blood was also collected to measure hemoglobin using a calibrated hematology analyzer (Sysmex XT-2000i), which was considered the true hemoglobin concentration for comparison purposes. Hemoglobin was determined first by AnemoCheck by placing the 10μL capillary into a 2mL screw cap polypropylene tube containing the chemical reagents. The tube was then vigorously shaken and after 60 seconds, was compared to a standardized color scale and the hemoglobin concentration was determined. The AnemoCheck results were obtained and recorded before any additional machine-determined results were available, to avoid potential bias. Results: For this pilot study, samples were collected from 40 children for hemoglobin determination by all three methods. The range of hemoglobin concentrations, based on results from the Sysmex hematology analyzer, was 4.8 – 9.2 g/dL (median 7.0). As illustrated in the Figure, the hemoglobin values obtained from the AnemoCheck assay correlated well with the Sysmex hematology analyzer results, r=0.74, p<0.0001. The AnemoCheck results were more accurate than the hemoglobin values obtained by the BioSystems Hemoglobin Analyzer (r=0.47, p=0.020), which is the primary mode of hemoglobin determination in the clinic. On average, the hemoglobin obtained by AnemoCheck was within 0.5 g/dL of the Sysmex value (range 0-1.9 g/dL), compared to the Biosystems value (absolute mean difference=0.7 g/dL, range 0-2.2 g/dL). Figure 1 Figure 1. Conclusions: Laboratory diagnosis of anemia is expensive and difficult in low resource settings such as Angola, where severe anemia is common and life-threatening. Our pilot data demonstrate that a novel, point-of-care, color-based assay that does not require electricity or expensive reagents is able to accurately estimate low hemoglobin concentrations. Further refinements of the AnemoCheck assay will include photographic color assessment and automated hemoglobin estimation, which will be helpful in resource-poor settings. This test has the potential to become extremely useful diagnostic tool in low resource hospitals and health centers, where sophisticated equipment and reagents may not be available. Disclosures No relevant conflicts of interest to declare.

scholarly journals Mortality reduction in ICU-admitted COVID-19 patients in Suriname after treatment with convalescent plasma acquired via gravity filtration

2021 ◽  
Author(s):  
Rosita Bihariesingh ◽  
Rakesh Bansie ◽  
Janeri Froberg ◽  
Navin Ramdhani ◽  
Rishi Mangroo ◽  
...  
Keyword(s):  
Disease Severity ◽  
Survival Probability ◽  
Standard Treatment ◽  
Therapeutic Option ◽  
Control Group ◽  
Icu Mortality ◽  
Filtration Method ◽  
Low Resource Settings ◽  
Low Resource ◽  
Life Threatening

Background Although convalescent plasma (CP) treatment is a potential therapeutic option for patients with COVID-19, there is a paucity of data from studies in low-resource settings. The efficacy and safety of CP therapy in intensive care unit (ICU) patients with COVID-19 in Suriname was evaluated. A novel gravity-based filtration method was used to obtain CP. The design was an open-label, multi-centre, non-randomized prospective clinical trial performed in two hospitals in Suriname, from June 2020, to December 2020. A pre-planned interim analysis is reported in 78 PCR-confirmed COVID-19 patients admitted to the ICU with severe or lifethreatening symptoms. CP in combination with standard treatment (n = 28) was compared to standard treatment alone (control) (n = 50), stratified by disease severity. The primary endpoint was 28-day ICU mortality. Secondary (exploratory) endpoints were changes two days after treatment initiation in pulmonary oxygen exchange capacity (PF ratio) and chest xray (CXR) score. Findings The median age of patients was 52 years with 43 [55.1%] being male. Twenty-eight day mortality occurred in 18% (5/28) of the CP group vs 36% (18/50) of the control group. Survival probability was significantly higher in the CP group compared to the control group with standard care (P=0.027). When stratifying into disease severity, the survival probability was the lowest for the control group with life-threatening disease (P=0.0051). CP treatment of severe COVID-19 resulted in a higher probability of survival, with a hazard ratio (HR) of 0.22 (95% CI, 0.074-0.067), correcting for age, the presence of diabetes and COVID-19 severity. Age significantly increased the mortality risk (HR, 1.08 [95%CI, 1.022-1.14]; P =0.006). In the severe group, CP resulted in an improved CXR score (P =0.0013) and increase in PF ratio (P = 0.011) as compared to standard therapy. The gravity-based plasmapheresis method used for CP production was well-tolerated and no adverse events were observed in the donors. Interpretation Among patients with severe or life-threatening COVID-19, CP therapy in combination with standard treatment resulted in 78% reduction of 28-day ICU mortality (HR = 0.22) compared to standard treatment alone. Both CXR-score and PF ratio changes represent indicators of treatment effect of CP after two days and can easily be implemented in low-resource settings. The novel CP production method was effective and represents a practical solution for low and middle income countries (LMICs) to produce CP locally. Although interpretation is limited by the non-randomised design of the trial, these results offer a potential route for broader implementation of CP treatment in LMICs.

scholarly journals Genomic characterization of the non-O1/non-O139 Vibrio cholerae strain that caused a gastroenteritis outbreak in Santiago, Chile, 2018

2019 ◽  
Author(s):  
Mónica Arteaga ◽  
Juliana Velasco ◽  
Shelly Rodriguez ◽  
Maricel Vidal ◽  
Carolina Arellano ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Sequence Data ◽  
Genomic Islands ◽  
Cholerae Strain ◽  
Supplementary Data ◽  
Gastroenteritis Outbreak ◽  
Secretion Systems ◽  
Pathogenic Potential ◽  
Data Files

AbstractVibrio cholerae is a human pathogen, which is transmitted by the consumption of contaminated food or water. V. cholerae strains belonging to the serogroups O1 and O139 can cause cholera outbreaks and epidemics, a severe life-threatening diarrheal disease. In contrast, serogroups other than O1 and O139, denominated as non-O1/non-O139, have been mainly associated with sporadic cases of moderate or mild diarrhea, bacteremia and wound infections. Here we investigated the virulence determinants and phylogenetic origin of a non-O1/non-O139 V. cholerae strain that caused a gastroenteritis outbreak in Santiago, Chile, 2018. We found that this outbreak strain lacks the classical virulence genes harboured by O1 and O139 strains, including the cholera toxin (CT) and the toxin-coregulated pilus (TCP). However, this strain carries genomic islands (GIs) encoding Type III and Type VI secretion systems (T3SS/T6SS) and antibiotic resistance genes. Moreover, we found these GIs are wide distributed among several lineages of non-O1/non-O139 strains. Our results suggest that the acquisition of these GIs may enhance the virulence of non-O1/non-O139 strains that lack the CT and TCP-encoding genes. Our results highlight the pathogenic potential of these V. cholerae strains.DATA SUMMARYSequence data were submitted to GenBank under the accession number SRLP00000000. The authors confirm that all supporting data and protocols have been provided within the article or through supplementary data files.Data statementAll supporting data, code and protocols have been provided within the article or through supplementary data files. Four supplementary tables are available with the online version of this article.

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