scholarly journals Reduced Infection Efficiency of Phage NCTC 12673 on Non-Motile Campylobacter jejuni Strains Is Related to Oxidative Stress

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1955
Author(s):  
Jessica C. Sacher ◽  
Muhammad Afzal Javed ◽  
Clay S. Crippen ◽  
James Butcher ◽  
Annika Flint ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Surface ◽  
Campylobacter Jejuni ◽  
Diarrheal Disease ◽  
Foodborne Pathogen ◽  
Flagellar Motility ◽  
Phenotypic Analysis ◽  
Host Interactions ◽  
Host Interaction ◽  
Human Infections

Campylobacter jejuni is a Gram-negative foodborne pathogen that causes diarrheal disease and is associated with severe post-infectious sequelae. Bacteriophages (phages) are a possible means of reducing Campylobacter colonization in poultry to prevent downstream human infections. However, the factors influencing phage-host interactions must be better understood before this strategy can be predictably employed. Most studies have focused on Campylobacter phage binding to the host surface, with all phages classified as either capsule- or flagella-specific. Here we describe the characterization of a C. jejuni phage that requires functional flagellar glycosylation and motor genes for infection, without needing the flagella for adsorption to the cell surface. Through phage infectivity studies of targeted C. jejuni mutants, transcriptomic analysis of phage-resistant mutants, and genotypic and phenotypic analysis of a spontaneous phage variant capable of simultaneously overcoming flagellar gene dependence and sensitivity to oxidative stress, we have uncovered a link between oxidative stress, flagellar motility, and phage infectivity. Taken together, our results underscore the importance of understanding phage-host interactions beyond the cell surface and point to host oxidative stress state as an important and underappreciated consideration for future phage-host interaction studies.

scholarly journals Interaction of Escherichia coli O157:H7 with Leafy Green Produce

2009 ◽  
Vol 72 (7) ◽  
pp. 1531-1537 ◽  
Author(s):  
JUAN XICOHTENCATL-CORTES ◽  
ETHEL SÁNCHEZ CHACÓN ◽  
ZEUS SALDAÑA ◽  
ENRIQUE FREER ◽  
JORGE A. GIRÓN
Keyword(s):  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Foodborne Pathogen ◽  
Enterohemorrhagic Escherichia Coli ◽  
Animal Products ◽  
Atpase Gene ◽  
Type 3 Secretion System ◽  
Human Infections ◽  
Type 3

Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen responsible for human diarrheal disease. EHEC lives in the intestinal tract of cattle and other farm and wild animals, which may be the source of environmental contamination particularly of agricultural fields. Human infections are associated with consumption of tainted animal products and fresh produce. How the bacteria interact with the plant phyllosphere and withstand industrial decontamination remain to be elucidated. The goals of the present study were to investigate the environmental conditions and surface structures that influence the interaction of EHEC O157:H7 with baby spinach and lettuce leaves in vitro. Independently of the production of Shiga toxin, EHEC O157:H7 colonizes the leaf surface via flagella and the type 3 secretion system (T3SS). Ultrastructural analysis of EHEC-infected leafy greens revealed the presence of flagellated bacteria, and mutation of the fliC flagellin gene in EHEC EDL933 rendered the bacteria significantly less adherent, suggesting the involvement of flagella in the bacteria-leaf interaction. EDL933 mutated in the escN (ATPase) gene associated with the function of the T3SS but not in the eae (intimin adhesin) gene required for adherence to host intestinal cells had significantly reduced adherence compared with that of the parental strain. The data suggest a compelling role of flagella and the T3SS in colonization of leafy green produce. Colonization of salad leaves by EHEC strains may be a strategy that ensures survival of these bacteria in the environment and allows transmission to the human host.

scholarly journals Inactivation of the core cheVAWY chemotaxis genes disrupts chemotactic motility and organised biofilm formation in Campylobacter jejuni

2018 ◽  
Author(s):  
Mark Reuter ◽  
Eveline Ultee ◽  
Yasmin Toseafa ◽  
Andrew Tan ◽  
Arnoud H.M. van Vliet
Keyword(s):  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Foodborne Pathogen ◽  
Flagellar Motility ◽  
The Core ◽  
Transmission Modes ◽  
Strain Nctc ◽  
Flagellar Assembly ◽  
Flagellar Proteins ◽  
Chemotaxis System

ABSTRACTFlagellar motility plays a central role in the bacterial foodborne pathogen Campylobacter jejuni, as flagellar motility is required for reaching the intestinal epithelium and subsequent colonisation or disease. Flagellar proteins also contribute strongly to biofilm formation during transmission. Chemotaxis is the process directing flagellar motility in response to attractant and repellent stimuli, but its role in biofilm formation of C. jejuni is not well understood. Here we show that inactivation of the core chemotaxis genes cheVAWY in C. jejuni strain NCTC 11168 affects both chemotactic motility and biofilm formation. Inactivation of any of the core chemotaxis genes (cheA, cheY, cheV or cheW) impaired chemotactic motility but did not affect flagellar assembly or growth. The ΔcheY mutant swam in clockwise loops, while complementation restored normal motility. Inactivation of the core chemotaxis genes interfered with the ability to form a discrete biofilm at the air-media interface, and the ΔcheY mutant displayed reduced dispersal/shedding of bacteria into the planktonic fraction. This suggests that while the chemotaxis system is not required for biofilm formation per se, it is necessary for organized biofilm formation. Hence interference with the Campylobacter chemotaxis system at any level disrupts optimal chemotactic motility and transmission modes such as biofilm formation.

scholarly journals Inactivation of the core cheVAWY chemotaxis genes disrupts chemotactic motility and organised biofilm formation in Campylobacter jejuni

2020 ◽  
Author(s):  
Mark Reuter ◽  
Eveline Ultee ◽  
Yasmin Toseafa ◽  
Andrew Tan ◽  
Arnoud H M van Vliet
Keyword(s):  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Foodborne Pathogen ◽  
Flagellar Motility ◽  
The Core ◽  
Transmission Modes ◽  
Strain Nctc ◽  
Flagellar Assembly ◽  
Flagellar Proteins ◽  
Chemotaxis System

Abstract Flagellar motility plays a central role in the bacterial foodborne pathogen Campylobacter jejuni, as flagellar motility is required for reaching the intestinal epithelium and subsequent colonisation or disease. Flagellar proteins also contribute strongly to biofilm formation during transmission. Chemotaxis is the process directing flagellar motility in response to attractant and repellent stimuli, but its role in biofilm formation of C. jejuni is not well understood. Here we show that inactivation of the core chemotaxis genes cheVAWY in C. jejuni strain NCTC 11168 affects both chemotactic motility and biofilm formation. Inactivation of any of the core chemotaxis genes (cheA, cheY, cheV or cheW) impaired chemotactic motility but did not affect flagellar assembly or growth. The ∆cheY mutant swam in clockwise loops, while complementation restored normal motility. Inactivation of the core chemotaxis genes interfered with the ability to form a discrete biofilm at the air-media interface, and the ∆cheY mutant displayed reduced dispersal/shedding of bacteria into the planktonic fraction. This suggests that while the chemotaxis system is not required for biofilm formation per se, it is necessary for organized biofilm formation. Hence interference with the Campylobacter chemotaxis system at any level disrupts optimal chemotactic motility and transmission modes such as biofilm formation.

scholarly journals Defects in Conidiophore Development and Conidium-Macrophage Interactions in a Dioxygenase Mutant of Aspergillus fumigatus

2008 ◽  
Vol 76 (7) ◽  
pp. 3214-3220 ◽  
Author(s):  
Taylor R. T. Dagenais ◽  
DaWoon Chung ◽  
Steven S. Giles ◽  
Christina M. Hull ◽  
David Andes ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aspergillus Fumigatus ◽  
Essential Role ◽  
Octadecadienoic Acid ◽  
Wild Type ◽  
Host Interactions ◽  
Host Interaction ◽  
Hydroperoxyoctadecadienoic Acid

ABSTRACT Oxygenated fatty acids, or oxylipins, play an essential role in physiological signaling and developmental processes in animals, plants, and fungi. Previous characterization of three Aspergillus fumigatus dioxygenases (PpoA, PpoB, and PpoC), similar in sequence to mammalian cyclooxygenases, showed that PpoA is responsible for the production of the oxylipins 8R-hydroperoxyoctadecadienoic acid and 5S,8R-dihydroxy-9Z,12Z-octadecadienoic acid and that PpoC is responsible for 10R-hydroxy-8E,12Z-hydroperoxyoctadecadienoic acid. Here, Δppo mutants were characterized to elucidate the role of fungal dioxygenases in A. fumigatus development and host interactions. The ΔppoC strain displayed distinct phenotypes compared to those of other Δppo mutants and the wild type, including altered conidium size, germination, and tolerance to oxidative stress as well as increased uptake and killing by primary alveolar macrophages. These experiments implicate oxylipins in pathogen development and suggest that ΔppoC represents a useful model for studying the A. fumigatus-host interaction.

scholarly journals Interaction of Copper Toxicity and Oxidative Stress in Campylobacter jejuni

2018 ◽  
Vol 200 (21) ◽  
Author(s):  
Susan P. Gardner ◽  
Jonathan W. Olson
Keyword(s):  
Oxidative Stress ◽  
Campylobacter Jejuni ◽  
Copper Toxicity ◽  
Foodborne Pathogen ◽  
Growth Media ◽  
Avian Host ◽  
Copper Binding ◽  
Copper Transporter ◽  
Content Type ◽  
Metabolic Requirement

ABSTRACT Copper is both a required micronutrient and a source of toxicity in most organisms, including Campylobacter jejuni. Two proteins expressed in C. jejuni (termed CopA and CueO) have been shown to be a copper transporter and multicopper oxidase, respectively. We have isolated strains with mutations in these genes, and here we report that they were more susceptible to both the addition of copper in the growth media and to induced oxidative stress. Both mutant strains were defective in colonization of an avian host, and copper in the feed exacerbated the colonization deficiency. Overexpression of a cytoplasmic peptide derived from the normally periplasmic copper-binding region of CueO also caused copper intolerance compared to nonexpressing strains or strains expressing the non-copper-binding versions of the peptide. Taken together, the results indicate that copper toxicity in C. jejuni is due to a failure to effectively sequester cytoplasmic copper, resulting in an increase in copper-mediated oxidative damage. IMPORTANCE Copper is a required micronutrient for most aerobic organisms, but it is universally toxic at elevated levels. These organisms use homeostatic mechanisms that allow for cells to acquire enough of the element to sustain metabolic requirements while ensuring that lethal levels cannot build up in the cell. Campylobacter jejuni is an important foodborne pathogen that typically makes its way into the food chain through contaminated poultry. C. jejuni has a metabolic requirement for copper and encodes a copper detoxification system. In the course of studying this system, we have learned that it is important for avian colonization. We have also gained insight into how copper exerts its toxic effects in C. jejuni by promoting oxidative stress.

scholarly journals The Campylobacter jejuni CiaD effector co-opts the host cell protein IQGAP1 to promote cell entry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicholas M. Negretti ◽  
Christopher R. Gourley ◽  
Prabhat K. Talukdar ◽  
Geremy Clair ◽  
Courtney M. Klappenbach ◽  
...  
Keyword(s):  
Host Cell ◽  
Campylobacter Jejuni ◽  
Foodborne Pathogen ◽  
Small Gtpase ◽  
Host Cells ◽  
Cell Protein ◽  
Host Cell Protein ◽  
Cell Binding ◽  
Actin Reorganization ◽  
Cell Cytosol

AbstractCampylobacter jejuni is a foodborne pathogen that binds to and invades the epithelial cells lining the human intestinal tract. Maximal invasion of host cells by C. jejuni requires cell binding as well as delivery of the Cia proteins (Campylobacter invasion antigens) to the host cell cytosol via the flagellum. Here, we show that CiaD binds to the host cell protein IQGAP1 (a Ras GTPase-activating-like protein), thus displacing RacGAP1 from the IQGAP1 complex. This, in turn, leads to the unconstrained activity of the small GTPase Rac1, which is known to have roles in actin reorganization and internalization of C. jejuni. Our results represent the identification of a host cell protein targeted by a flagellar secreted effector protein and demonstrate that C. jejuni-stimulated Rac signaling is dependent on IQGAP1.

scholarly journals The Interplay between Campylobacter and the Caecal Microbial Community of Commercial Broiler Chickens over Time

2021 ◽  
Vol 9 (2) ◽  
pp. 221
Author(s):  
Ilaria Patuzzi ◽  
Massimiliano Orsini ◽  
Veronica Cibin ◽  
Sara Petrin ◽  
Eleonora Mastrorilli ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Broiler Chickens ◽  
Control Strategies ◽  
Chicken Meat ◽  
Control Measures ◽  
Microbial Network ◽  
Gut Colonization ◽  
Commercial Broiler ◽  
Zoonotic Bacteria ◽  
Human Infections

Campylobacter is the most frequent foodborne zoonotic bacteria worldwide, with chicken meat being overwhelmingly the most important reservoir for human infections. Control measures implemented at the farm level (i.e., biosecurity or vaccination), which have been successfully applied to limit other pathogens, such as Salmonella, have not been effective in reducing Campylobacter occurrence. Thus, new approaches are needed to fully understand the ecological interactions of Campylobacter with host animals to effectively comprehend its epidemiology. The objective of this study was to analyse longitudinally the gut microbiota composition of Campylobacter-infected and non-infected farms to identify any difference that could potentially be indicative of gut colonization by Campylobacter spp. Differences in the colonization rate and timing were observed at the farms that became positive for Campylobacter jejuni over the investigated time points, even though in positive tests, the occurrence of Campylobacter jejuni gut colonization was not observed before the second week of the life of the birds. Significant differences were observed in the abundances of specific bacterial taxa between the microbiota of individuals belonging to farms that became Campylobacter positive during the study and those who remained negative with particular reference to Bacteroidales and Clostridiales, respectively. Moreover, Campylobacter colonization dramatically influenced the microbiota richness, although to a different extent depending on the infection timing. Finally, a key role of Faecalibacterium and Lactobacillus genera on the Campylobacter microbial network was observed. Understanding the ecology of the Campylobacter interaction with host microbiota during infection could support novel approaches for broiler microbial barrier restoration. Therefore, evidence obtained through this study can be used to identify options to reduce the incidence of infection at a primary production level based on the targeted influence of the intestinal microbiota, thus helping develop new control strategies in order to mitigate the risk of human exposure to Campylobacter by chicken meat consumption.

scholarly journals Organoids to Dissect Gastrointestinal Virus–Host Interactions: What Have We Learned?

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 999
Author(s):  
Sue E. Crawford ◽  
Sasirekha Ramani ◽  
Sarah E. Blutt ◽  
Mary K. Estes
Keyword(s):  
Cell Types ◽  
Human Infection ◽  
Viral Pathogens ◽  
Host Interactions ◽  
Complex Interactions ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Human Intestinal Epithelium ◽  
Human Viruses ◽  
Human Infections

Historically, knowledge of human host–enteric pathogen interactions has been elucidated from studies using cancer cells, animal models, clinical data, and occasionally, controlled human infection models. Although much has been learned from these studies, an understanding of the complex interactions between human viruses and the human intestinal epithelium was initially limited by the lack of nontransformed culture systems, which recapitulate the relevant heterogenous cell types that comprise the intestinal villus epithelium. New investigations using multicellular, physiologically active, organotypic cultures produced from intestinal stem cells isolated from biopsies or surgical specimens provide an exciting new avenue for understanding human specific pathogens and revealing previously unknown host–microbe interactions that affect replication and outcomes of human infections. Here, we summarize recent biologic discoveries using human intestinal organoids and human enteric viral pathogens.

scholarly journals The Phosphoarginine Phosphatase PtpB from Staphylococcus aureus Is Involved in Bacterial Stress Adaptation during Infection

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 645
Author(s):  
Mohamed Ibrahem Elhawy ◽  
Sylvaine Huc-Brandt ◽  
Linda Pätzold ◽  
Laila Gannoun-Zaki ◽  
Ahmed Mohamed Mostafa Abdrabou ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Treatment Strategies ◽  
Physiological Role ◽  
Aureus Strain ◽  
Stress Adaptation ◽  
Cellular Mechanisms ◽  
Host Interaction ◽  
Liver And Kidney

Staphylococcus aureus continues to be a public health threat, especially in hospital settings. Studies aimed at deciphering the molecular and cellular mechanisms that underlie pathogenesis, host adaptation, and virulence are required to develop effective treatment strategies. Numerous host-pathogen interactions were found to be dependent on phosphatases-mediated regulation. This study focused on the analysis of the role of the low-molecular weight phosphatase PtpB, in particular, during infection. Deletion of ptpB in S. aureus strain SA564 significantly reduced the capacity of the mutant to withstand intracellular killing by THP-1 macrophages. When injected into normoglycemic C57BL/6 mice, the SA564 ΔptpB mutant displayed markedly reduced bacterial loads in liver and kidney tissues in a murine S. aureus abscess model when compared to the wild type. We also observed that PtpB phosphatase-activity was sensitive to oxidative stress. Our quantitative transcript analyses revealed that PtpB affects the transcription of various genes involved in oxidative stress adaptation and infectivity. Thus, this study disclosed first insights into the physiological role of PtpB during host interaction allowing us to link phosphatase-dependent regulation to oxidative bacterial stress adaptation during infection.

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