scholarly journals Multifunctional transcription factor CytR of Vibrio cholerae is important for pathogenesis

Microbiology ◽  
2020 ◽  
Vol 166 (12) ◽  
pp. 1136-1148 ◽  
Author(s):  
Suman Das ◽  
Rhishita Chourashi ◽  
Priyadarshini Mukherjee ◽  
Animesh Gope ◽  
Hemanta Koley ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Vibrio Cholerae ◽  
Significant Role ◽  
Type Species ◽  
Vital Role ◽  
Class Iii ◽  
Content Type ◽  
Link Type ◽  
Isogenic Mutant Strain ◽  
Mucin Layer

Vibrio cholerae, the Gram-negative facultative pathogen, resides in the aquatic environment and infects humans and causes diarrhoeagenic cholera. Although the environment differs drastically, V. cholerae thrives in both of these conditions aptly and chitinases play a vital role in their persistence and nutrient acquisition. Chitinases also play a role in V. cholerae pathogenesis. Chitinases and its downstream chitin utilization genes are regulated by sensor histidine kinase ChiS, which also plays a significant role in pathogenesis. Recent exploration suggests that CytR, a transcription factor of the LacI family in V. cholerae, also regulates chitinase secretion in environmental conditions. Since chitinases and chitinase regulator ChiS is involved in pathogenesis, CytR might also play a significant role in pathogenicity. However, the role of CytR in pathogenesis is yet to be known. This study explores the regulation of CytR on the activation of ChiS in the presence of mucin and its role in pathogenesis. Therefore, we created a CytR isogenic mutant strain of V. cholerae (CytR¯) and found considerably less β-hexosaminidase enzyme production, which is an indicator of ChiS activity. The CytR¯ strain greatly reduced the expression of chitinases chiA1 and chiA2 in mucin-supplemented media. Electron microscopy showed that the CytR¯ strain was aflagellate. The expression of flagellar-synthesis regulatory genes flrB, flrC and class III flagellar-synthesis genes were reduced in the CytR¯ strain. The isogenic CytR mutant showed less growth compared to the wild-type in mucin-supplemented media as well as demonstrated highly retarded motility and reduced mucin-layer penetration. The CytR mutant revealed decreased adherence to the HT-29 cell line. In animal models, reduced fluid accumulation and colonization were observed during infection with the CytR¯ strain due to reduced expression of ctxB, toxT and tcpA. Collectively these data suggest that CytR plays an important role in V. cholerae pathogenesis.

Two regulatory factors of Vibrio cholerae activating the mannose-sensitive haemagglutinin pilus expression is important for biofilm formation and colonization in mice

Microbiology ◽  
2021 ◽  
Vol 167 (10) ◽  
Author(s):  
Mengting Shi ◽  
Yue Zheng ◽  
Xianghong Wang ◽  
Zhengjia Wang ◽  
Menghua Yang
Keyword(s):  
Mouse Model ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Type Species ◽  
Wild Type ◽  
Expression Library ◽  
Content Type ◽  
Genomic Expression ◽  
Infant Mouse ◽  
Link Type

Vibrio cholerae the causative agent of cholera, uses a large number of coordinated transcriptional regulatory events to transition from its environmental reservoir to the host intestine, which is its preferred colonization site. Transcription of the mannose-sensitive haemagglutinin pilus (MSHA), which aids the persistence of V. cholerae in aquatic environments, but causes its clearance by host immune defenses, was found to be regulated by a yet unknown mechanism during the infection cycle of V. cholerae . In this study, genomic expression library screening revealed that two regulators, VC1371 and VcRfaH, are able to positively activate the transcription of MSHA operon. VC1371 is localized and active in the cell membrane. Deletion of vc1371 or VcrfaH genes in V. cholerae resulted in less MshA protein production and less efficiency of biofilm formation compared to that in the wild-type strain. An adult mouse model showed that the mutants with vc1371 or VcrfaH deletion colonized less efficiently than the wild-type; the VcrfaH deletion mutant showed less colonization efficiency in the infant mouse model. The findings strongly suggested that the two regulators, namely VC1371 and VcRfaH, which are involved in the regulation of MSHA expression, play an important role in V. cholerae biofilm formation and colonization in mice.

Molecular characterization of Vibrio cholerae O1 isolates obtained from outbreaks in the Philippines, 2015–2016

2021 ◽  
Vol 70 (11) ◽  
Author(s):  
Mark Philip Bugayong ◽  
Hidemasa Izumiya ◽  
Josie M. Bilar ◽  
Masatomo Morita ◽  
Eiji Arakawa ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
Variable Number Tandem Repeat ◽  
The Philippines ◽  
Large Chromosome ◽  
Content Type ◽  
Link Type ◽  
Mlva Type ◽  
El Tor

Introduction. The Philippines, comprising three island groups, namely, Luzon, Visayas and Mindanao, experienced an increase in cholera outbreaks in 2016. Previous studies have shown that Vibrio cholerae isolates obtained from the Philippines are novel hybrid El Tor strains that have evolved in the country and are clearly distinct from those found in Mozambique and Cameroon. Gap statement. The characterization of the strains isolated from outbreaks has been limited to phenotypic characteristics, such as biochemical and serological characteristics, in most previous studies. Aim. We performed multilocus variable-number tandem repeat (VNTR) analysis (MLVA) for V. cholerae isolates obtained from 2015 to 2016 to further characterize and understand the emergence and dissemination of the strains in the Philippines. Methodology. A total of 139 V . cholerae O1 Ogawa biotype El Tor isolates were obtained from the Philippines during diarrhoeal outbreaks in 18 provinces between 2015 and 2016. VNTR data were analysed to classify the MLVA profiles where the large-chromosome types (LCTs) were applied for grouping. Results. We identified 50 MLVA types among 139 isolates originating from 18 provinces, and 14 LCTs. The distribution of the LCTs was variable, and a few were located in specific areas or even in specific provinces. Based on eBURST analysis, 99 isolates with 7 LCTs and 32 MLVA types belonged to 1 group, suggesting that they were related to each other. LCT A was predominant (n=67) and was isolated from Luzon and Visayas. LCT A had 14 MLVA types; however, it mostly emerged during a single quarter of a year. Eight clusters were identified, each of which involved specific MLVA type(s). The largest cluster involved 23 isolates showing 3 MLVA types, 21 of which were MLVA type A-14 isolated from Negros Occidental during quarter 4 of 2016. Comparative analysis showed that almost all isolates from the Philippines were distinct from those in other countries. Conclusions. The genotypic relationship of the V. cholerae isolates obtained during outbreaks in the Philippines was studied, and their emergence and dissemination were elucidated. MLVA revealed the short-term dynamics of V. cholerae genotypes in the Philippines.

scholarly journals gbpA and chiA genes are not uniformly distributed amongst diverse Vibrio cholerae

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
Thea G. Fennell ◽  
Grace A. Blackwell ◽  
Nicholas R. Thomson ◽  
Matthew J. Dorman
Keyword(s):  
Vibrio Cholerae ◽  
Metabolic Pathway ◽  
Type Species ◽  
Gene Encoding ◽  
Natural Competence ◽  
Content Type ◽  
Metabolic Substrate ◽  
Link Type ◽  
Reference Strains ◽  
Present Experimental Evidence

Members of the bacterial genus Vibrio utilize chitin both as a metabolic substrate and a signal to activate natural competence. Vibrio cholerae is a bacterial enteric pathogen, sub-lineages of which can cause pandemic cholera. However, the chitin metabolic pathway in V. cholerae has been dissected using only a limited number of laboratory strains of this species. Here, we survey the complement of key chitin metabolism genes amongst 195 diverse V. cholerae . We show that the gene encoding GbpA, known to be an important colonization and virulence factor in pandemic isolates, is not ubiquitous amongst V. cholerae . We also identify a putatively novel chitinase, and present experimental evidence in support of its functionality. Our data indicate that the chitin metabolic pathway within V. cholerae is more complex than previously thought, and emphasize the importance of considering genes and functions in the context of a species in its entirety, rather than simply relying on traditional reference strains.

scholarly journals Phylogenetic and antimicrobial drug resistance analysis of Vibrio cholerae O1 isolates from Ghana

2021 ◽  
Vol 7 (10) ◽  
Author(s):  
Japheth A. Opintan ◽  
Robert C. Will ◽  
George K. Kuma ◽  
Mary Osei ◽  
Amos Akumwena ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
Lag Phase ◽  
Environmental Isolates ◽  
Content Type ◽  
Antimicrobial Drug Resistance ◽  
Link Type ◽  
Pathogen Persistence ◽  
Vibrio Cholerae O1 ◽  
Vaccination Campaigns

We investigated the evolution, phylogeny and antimicrobial resistance of Vibrio cholerae O1 isolates (VCO1) from Ghana. Outbreak and environmental sources of VCO1 were characterized, whole-genome sequenced and compared to globally available seventh pandemic (7P) strains of V. cholerae at SNP resolution. Final analyses included 636 isolates. Novel Ghanaian isolates clustered into three distinct clades (clades 1, 2 and 3) in wave 3 of the 7P lineage. The closest relatives of our novel Ghanaian isolates were from Benin, Cameroon, Togo, Niger and Nigeria. All novel Ghanaian isolates were multi-drug resistant. Environmental isolates clustered into clade 2, despite being isolated years later, showing the possibility of persistence and re-emergence of older clades. A lag phase of several years from estimated introduction to reported cases suggests pathogen persistence in the absence of reported cholera cases. These results highlight the importance of deeper surveillance for understanding transmission routes between bordering countries and planning tailored vaccination campaigns in an effort to eradicate cholera.

The enigma of Pacini’s Vibrio cholerae discovery

2021 ◽  
Vol 70 (11) ◽  
Author(s):  
Gian Piero Carboni
Keyword(s):  
Vibrio Cholerae ◽  
Intestinal Mucosa ◽  
Type Species ◽  
Polluted Water ◽  
Cholera Outbreak ◽  
Histological Techniques ◽  
Content Type ◽  
Link Type ◽  
Mutual Knowledge ◽  
Worldwide Distribution

During the 1854 cholera outbreak in Florence, Italy, Filippo Pacini documented that the cause of the infection was a bacterium. This conclusion was also independently reached by John Snow during the 1854 cholera outbreak in London. By using an epidemiological method, Snow found that the infection spread through a polluted water network. Snow identified a water pump as the source of the disease. After removing the infected handle of this pump, the cases of cholera rapidly began to decrease. A microscopic examination of the water showed organic impurities but no bacteria. This discovery was ignored during Snow’s lifetime. In contrast, through microscopy during the autopsies of cholera victims, Pacini observed that the disruption of their intestinal mucosa was closely associated with millions of the bacteria that he called Vibrio cholerae . Via histological techniques, Pacini detected that intestinal mucosa reabsorption dysfunction was the cause of debilitating diarrhoea, vomiting, severe dehydration and death. Nevertheless, his discovery of Vibrio cholerae was ignored during Pacini’s lifetime. A survey of Pacini’s autographic manuscripts suggests that Pacini and Snow may have shared mutual knowledge within their respective seminal papers. This survey also facilitates, for the first time, the creation of maps that illustrate the worldwide distribution of Pacini’s cholera papers from 1854 to 1881. The consistent neglect of Pacini’s discovery remains a true enigma.

scholarly journals Vibrio metoecus sp. nov., a close relative of Vibrio cholerae isolated from coastal brackish ponds and clinical specimens

2014 ◽  
Vol 64 (Pt_9) ◽  
pp. 3208-3214 ◽  
Author(s):  
Paul C. Kirchberger ◽  
Maryann Turnsek ◽  
Dana E. Hunt ◽  
Bradd J. Haley ◽  
Rita R. Colwell ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
The United States ◽  
Nucleotide Identity ◽  
Close Relative ◽  
Average Nucleotide Identity ◽  
Content Type ◽  
The Past ◽  
Link Type ◽  
Close Resemblance

A Gram-staining-negative, curved-rod-shaped bacterium with close resemblance to Vibrio cholerae , the aetiological agent of cholera, was isolated over the course of several years from coastal brackish water (17 strains) and from clinical cases (two strains) in the United States. 16S rRNA gene identity with V. cholerae exceeded 98 % yet an average nucleotide identity based on genome data of around 86 % and multi locus sequence analysis of six housekeeping genes (mdh, adk, gyrB, recA, pgi and rpoB) clearly delineated these isolates as a distinct genotypic cluster within the V. cholerae – V. mimicus clade. Most standard identification techniques do not differentiate this cluster of isolates from V. cholerae . Only amplification of the ompW gene using V. cholerae -specific primers and a negative Voges–Proskauer test showed a difference between the two clusters. Additionally, all isolated strains differed phenotypically from V. cholerae in their ability to utilize N-acetyl-d-galactosamine and d-glucuronic acid as sole carbon sources. Furthermore, they were generally unable to infect the slime mould Dictyostelium discoideum, a widespread ability in V. cholerae . Based on these clear phenotypic differences that are not necessarily apparent in standard tests as well as average nucleotide identity and phylogeny of protein-coding genes, we propose the existence of a novel species, Vibrio metoecus sp. nov. with the type strain OP3HT ( = LMG 27764T = CIP 110643T). Due to its close resemblance to V. cholerae and the increasing number of strains isolated over the past several years, we suggest that V. metoecus sp. nov. is a relatively common species of the genus Vibrio , isolates of which have been identified as atypical isolates of V. cholerae in the past. Its isolation from clinical samples also indicates that strains of this species, like V. cholerae , are opportunistic pathogens.

scholarly journals A mutagenic screen reveals NspS residues important for regulation of Vibrio cholerae biofilm formation

Microbiology ◽  
2021 ◽  
Author(s):  
Erin C. Young ◽  
Jackson T. Baumgartner ◽  
Ece Karatan ◽  
Misty L. Kuhn
Keyword(s):  
Signal Transduction ◽  
Ligand Binding ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Type Species ◽  
Binding Proteins ◽  
Signal Transduction Pathway ◽  
Signalling Pathway ◽  
Content Type ◽  
Link Type

Biofilm formation in the human intestinal pathogen Vibrio cholerae is in part regulated by norspermidine, spermidine and spermine. V. cholerae senses these polyamines through a signalling pathway consisting of the periplasmic protein, NspS, and the integral membrane c-di-GMP phosphodiesterase MbaA. NspS and MbaA belong to a proposed class of novel signalling systems composed of periplasmic ligand-binding proteins and membrane-bound c-di-GMP phosphodiesterases containing both GGDEF and EAL domains. In this signal transduction pathway, NspS is hypothesized to interact with MbaA in the periplasm to regulate its phosphodiesterase activity. Polyamine binding to NspS likely alters this interaction, leading to the activation or inhibition of biofilm formation depending on the polyamine. The purpose of this study was to determine the amino acids important for NspS function. We performed random mutagenesis of the nspS gene, identified mutant clones deficient in biofilm formation, determined their responsiveness to norspermidine and mapped the location of these residues onto NspS homology models. Single mutants clustered on two lobes of the NspS model, but the majority were found on a single lobe that appeared to be more mobile upon norspermidine binding. We also identified residues in the putative ligand-binding site that may be important for norspermidine binding and interactions with MbaA. Ultimately, our results provide new insights into this novel signalling pathway in V. cholerae and highlight differences between periplasmic binding proteins involved in transport versus signal transduction.

scholarly journals Genomic contextualisation of ancient DNA molecular data from an Argentinian fifth pandemic Vibrio cholerae infection

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
Matthew J. Dorman ◽  
Nicholas R. Thomson ◽  
Josefina Campos
Keyword(s):  
Latin America ◽  
Vibrio Cholerae ◽  
Ancient Dna ◽  
Type Species ◽  
Molecular Data ◽  
Molecular Evidence ◽  
Genomic Context ◽  
Content Type ◽  
The Past ◽  
Link Type

Specific lineages of serogroup O1 Vibrio cholerae are notorious for causing cholera pandemics, of which there have been seven since the 1800s. Much is known about the sixth pandemic (1899–1923) and the ongoing seventh pandemic (1961–present), but we know very little about the bacteriology of pandemics 1 to 5. Moreover, although we are learning about the contribution of non-O1 non-pandemic V. cholerae to cholera dynamics during the current pandemic, we know almost nothing about their role in the past. A recent ancient DNA study has presented what may be the first molecular evidence of a V. cholerae infection from the fifth cholera pandemic period (1886–1887 AD) in Argentina. Here, we place the molecular evidence from that study into the genomic context of non-pandemic V. cholerae from Latin America and elsewhere, and show that a gene fragment amplified from ancient DNA is most similar to that of V. cholerae from the Americas, and from Argentina. Our results corroborate and reinforce the findings of the original study, and collectively suggest that even in the 1880s, non-pandemic V. cholerae local to the Americas may have caused sporadic infections in Argentina, just as we know this to have happened during the seventh pandemic in Latin America.

Quantification of Vibrio cholerae cholix exotoxin by sandwich bead-ELISA

2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Sharda Prasad Awasthi ◽  
Nityananda Chowdhury ◽  
Noritoshi Hatanaka ◽  
Atsushi Hinenoya ◽  
Thandavarayan Ramamurthy ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
Sandwich Elisa ◽  
Luria Bertani ◽  
Production Level ◽  
Quantitative Assay ◽  
Growth Media ◽  
Mice Model ◽  
Content Type ◽  
Link Type

Introduction. Cholix toxin (ChxA) is an ADP-ribosylating exotoxin produced by Vibrio cholerae . However, to date, there is no quantitative assay available for ChxA, which makes it difficult to detect and estimate the level of ChxA produced by V. cholerae . Hypothesis/Gap Statement. It is important to develop a reliable and specific quantitative assay to measure the production level of ChxA, which will help us to understand the role of ChxA in V. cholerae pathogenesis. Aim. The aim of this study was to develop a bead-based sandwich ELISA (bead-ELISA) for the quantification of ChxA and to evaluate the importance of ChxA in the pathogenesis of V. cholerae infection. Methodology. Anti-rChxA was raised in New Zealand white rabbits, and Fab-horse radish peroxidase conjugate was prepared by the maleimide method to use in the bead-ELISA. This anti-ChxA bead-ELISA was applied to quantify the ChxA produced by various V. cholerae strains. The production of ChxA was examined in different growth media such as alkaline peptone water (APW), Luria-Bertani broth and AKI. Finally, the assay was evaluated using a mouse lethality assay with representative V. cholerae strains categorized as low to high ChxA-producers based on anti-ChxA bead-ELISA. Results. A sensitive bead-ELISA assay, which can quantify from 0.6 to 60 ng ml−1 of ChxA, was developed. ChxA was mostly detected in the extracellular cell-free supernatant and its production level varied from 1.2 ng ml−1 to 1.6 µg ml−1. The highest ChxA production was observed when V. cholerae strains were cultured in LB broth, but not in APW or AKI medium. The ChxA-producer V. cholerae strains showed 20–80 % lethality and only the high ChxA II-producer was statistically more lethal than a non-ChxA-producer, in the mice model assay. ChxA I and II production levels were not well correlated with mice lethality, and this could be due to the heterogeneity of the strains tested. Conclusion. ChxA I to III was produced mostly extracellularly at various levels depending on strains and culture conditions. The bead-ELISA developed in this study is useful for the detection and quantification of ChxA in V. cholerae strains.

scholarly journals Siderophore piracy enhances Vibrio cholerae environmental survival and pathogenesis

Microbiology ◽  
2020 ◽  
Vol 166 (11) ◽  
pp. 1038-1046 ◽  
Author(s):  
Hyuntae Byun ◽  
I-Ji Jung ◽  
Jiandong Chen ◽  
Jessie Larios Valencia ◽  
Jay Zhu
Keyword(s):  
Vibrio Cholerae ◽  
Type Species ◽  
Iron Acquisition ◽  
Content Type ◽  
Iron Restriction ◽  
Environmental Survival ◽  
Link Type ◽  
Adult Mice ◽  
Polymicrobial Communities

Vibrio cholerae, the aetiological agent of cholera, possesses multiple iron acquisition systems, including those for the transport of siderophores. How these systems benefit V. cholerae in low-iron, polymicrobial communities in environmental settings or during infection remains poorly understood. Here, we demonstrate that in iron-limiting conditions, co-culture of V. cholerae with a number of individual siderophore-producing microbes significantly promoted V. cholerae growth in vitro. We further show that in the host environment with low iron, V. cholerae colonizes better in adult mice in the presence of the siderophore-producing commensal Escherichia coli . Taken together, our results suggest that in aquatic reservoirs or during infection, V. cholerae may overcome environmental and host iron restriction by hijacking siderophores from other microbes.

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