Ceramide in bacterial infections and cystic fibrosis

2008 ◽  
Vol 389 (11) ◽  
Author(s):  
Heike Grassmé ◽  
Katrin Anne Becker ◽  
Yang Zhang ◽  
Erich Gulbins
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
De Novo ◽  
Acid Sphingomyelinase ◽  
Temporal Organization ◽  
Host Cells ◽  
Host Responses ◽  
Mammalian Host ◽  
Membrane Domains

AbstractCeramide is formed by the activity of sphingomyelinases, by degradation of complex sphingolipids, reverse ceramidase activity orde novosynthesized. The formation of ceramide within biological membranes results in the formation of large ceramide-enriched membrane domains. These domains serve the spatial and temporal organization of receptors and signaling molecules. The acid sphingomyelinase-ceramide system plays an important role in the infection of mammalian host cells with bacterial pathogens such asNeisseria gonorrhoeae,Escherichia coli,Staphylococcus aureus,Listeria monocytogenes,Salmonella typhimuriumandPseudomonas aeruginosa. Ceramide and ceramide-enriched membrane platforms are also involved in the induction of apoptosis in infected cells, such as in epithelial and endothelial cells after infection withPseudomonas aeruginosaandStaphylococcus aureus, respectively. Finally, ceramide-enriched membrane platforms are critical regulators of the release of pro-inflammatory cytokines upon infection. The diverse functions of ceramide in bacterial infections suggest that ceramide and ceramide-enriched membrane domains are key players in host responses to many pathogens and thus are potential novel targets to treat infections.

scholarly journals Bacteriophage-Based Biosensing of Pseudomonas aeruginosa: An Integrated Approach for the Putative Real-Time Detection of Multi-Drug-Resistant Strains

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 124
Author(s):  
Liliam K. Harada ◽  
Waldemar Bonventi Júnior ◽  
Erica C. Silva ◽  
Thais J. Oliveira ◽  
Fernanda C. Moreli ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Research Effort ◽  
Acquired Resistance ◽  
Integrated Approach ◽  
Healthcare Services ◽  
Host Cells ◽  
Color Changes ◽  
Metabolic Versatility ◽  
The Matrix

During the last decennium, it has become widely accepted that ubiquitous bacterial viruses, or bacteriophages, exert enormous influences on our planet’s biosphere, killing between 4–50% of the daily produced bacteria and constituting the largest genetic diversity pool on our planet. Currently, bacterial infections linked to healthcare services are widespread, which, when associated with the increasing surge of antibiotic-resistant microorganisms, play a major role in patient morbidity and mortality. In this scenario, Pseudomonas aeruginosa alone is responsible for ca. 13–15% of all hospital-acquired infections. The pathogen P. aeruginosa is an opportunistic one, being endowed with metabolic versatility and high (both intrinsic and acquired) resistance to antibiotics. Bacteriophages (or phages) have been recognized as a tool with high potential for the detection of bacterial infections since these metabolically inert entities specifically attach to, and lyse, bacterial host cells, thus, allowing confirmation of the presence of viable cells. In the research effort described herein, three different phages with broad lytic spectrum capable of infecting P. aeruginosa were isolated from environmental sources. The isolated phages were elected on the basis of their ability to form clear and distinctive plaques, which is a hallmark characteristic of virulent phages. Next, their structural and functional stabilization was achieved via entrapment within the matrix of porous alginate, biopolymeric, and bio-reactive, chromogenic hydrogels aiming at their use as sensitive matrices producing both color changes and/or light emissions evolving from a reaction with (released) cytoplasmic moieties, as a bio-detection kit for P. aeruginosa cells. Full physicochemical and biological characterization of the isolated bacteriophages was the subject of a previous research paper.

scholarly journals Type III Secretion Decreases Bacterial and Host Survival following Phagocytosis of Yersinia pseudotuberculosis by Macrophages

2008 ◽  
Vol 76 (9) ◽  
pp. 4299-4310 ◽  
Author(s):  
Yue Zhang ◽  
James Murtha ◽  
Margaret A. Roberts ◽  
Richard M. Siegel ◽  
James B. Bliska
Keyword(s):  
Cell Death ◽  
Type Iii Secretion ◽  
Yersinia Pseudotuberculosis ◽  
De Novo ◽  
Host Cells ◽  
Host Responses ◽  
Intracellular Bacteria ◽  
Wild Type ◽  
Macrophage Response ◽  
Type Iii

ABSTRACT Yersinia pseudotuberculosis uses a plasmid (pYV)-encoded type III secretion system (T3SS) to translocate a set of effectors called Yops into infected host cells. YopJ functions to induce apoptosis, and YopT, YopE, and YopH act to antagonize phagocytosis in macrophages. Because Yops do not completely block phagocytosis and Y. pseudotuberculosis can replicate in macrophages, it is important to determine if the T3SS modulates host responses to intracellular bacteria. Isogenic pYV-cured, pYV+ wild-type, and yop mutant Y. pseudotuberculosis strains were allowed to infect bone marrow-derived murine macrophages at a low multiplicity of infection under conditions in which the survival of extracellular bacteria was prevented. Phagocytosis, the intracellular survival of the bacteria, and the apoptosis of the infected macrophages were analyzed. Forty percent of cell-associated wild-type bacteria were intracellular after a 20-min infection, allowing the study of the macrophage response to internalized pYV+ Y. pseudotuberculosis. Interestingly, macrophages restricted survival of pYV+ but not pYV-cured or ΔyopB Y. pseudotuberculosis within phagosomes: only a small fraction of the pYV+ bacteria internalized replicated by 24 h. In addition, ∼20% of macrophages infected with wild-type pYV+ Y. pseudotuberculosis died of apoptosis after 20 h. Analysis of yop mutants expressing catalytically inactive effectors revealed that YopJ was important for apoptosis, while a role for YopE, YopH, and YopT in modulating macrophage responses to intracellular bacteria could not be identified. Apoptosis was reduced in Toll-like receptor 4-deficient macrophages, indicating that cell death required signaling through this receptor. Treatment of macrophages harboring intracellular pYV+ Y. pseudotuberculosis with chloramphenicol reduced apoptosis, indicating that the de novo bacterial protein synthesis was necessary for cell death. Our finding that the presence of a functional T3SS impacts the survival of both bacterium and host following phagocytosis of Y. pseudotuberculosis suggests new roles for the T3SS in Yersinia pathogenesis.

scholarly journals Pseudomonas aeruginosa and Staphylococcus aureus virulence factors as biomarkers of infection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Artur J. Sabat ◽  
Daniele Pantano ◽  
Viktoria Akkerboom ◽  
Erik Bathoorn ◽  
Alexander W. Friedrich
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Clinical Status ◽  
Clinical Samples ◽  
Pathogenic Microorganisms ◽  
Bacterial Identification ◽  
Accurate Identification ◽  
Culture Independent ◽  
And Staphylococcus Aureus

Abstract The gold standard for the diagnosis of bacterial infections in clinical samples is based on culture tests that are time-consuming and labor-intense. For these reasons, an extraordinary effort has been made to identify biomarkers as the tools for sensitive, rapid and accurate identification of pathogenic microorganisms. Moreover, biomarkers have been tested to distinguish colonization from infection, monitor disease progression, determine the clinical status of patients or predict clinical outcomes. This mini-review describes Pseudomonas aeruginosa and Staphylococcus aureus biomarkers, which contribute to pathogenesis and have been used in culture-independent bacterial identification directly from patient samples.

scholarly journals Pseudomonas aeruginosa injects NDK into host cells through a type III secretion system

Microbiology ◽  
2014 ◽  
Vol 160 (7) ◽  
pp. 1417-1426 ◽  
Author(s):  
Dennis Neeld ◽  
Yongxin Jin ◽  
Candace Bichsel ◽  
Jinghua Jia ◽  
Jianhui Guo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Mammalian Host ◽  
Type I ◽  
Dependent Manner ◽  
Type Iii

Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen possessing a type III secretion system (T3SS) which injects toxic effector proteins into mammalian host cells. In previous studies, P. aeruginosa strains lacking all of the known type III effectors were shown to cause cytotoxicity upon prolonged infection time. In this study, we report the identification of a new cytotoxin, nucleoside diphosphate kinase (NDK), which is injected into eukaryotic cells in a T3SS-dependent manner. Injection of NDK is inhibited by the presence of previously known effectors of the T3SS, with an effectorless strain injecting the highest amount, suggesting active competition with the known T3SS effectors. NDK is shown to cause a cytotoxic response when expressed in eukaryotic cells, and P. aeruginosa strains harbouring NDK also show a greater toxicity than strains lacking it. Interestingly, the cytotoxic effect of intracellular NDK is independent of its kinase activity. In previous studies, NDK was shown to be secreted into culture supernatants via a type I secretion system and cause cytotoxicity in a kinase-dependent manner. Therefore, the current study highlights an alternative route of NDK secretion as well as two different cytotoxic mechanisms of NDK, depending on the extra- or intra-cellular location of the protein.

scholarly journals Optimization of a High-Throughput 384-Well Plate-Based Screening Platform with Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 15442 Biofilms

2020 ◽  
Vol 21 (9) ◽  
pp. 3034 ◽  
Author(s):  
Shella Gilbert-Girard ◽  
Kirsi Savijoki ◽  
Jari Yli-Kauhaluoma ◽  
Adyary Fallarero
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
High Throughput ◽  
High Throughput Screening ◽  
Bacterial Infections ◽  
Rapid Screening ◽  
Bacterial Biofilms ◽  
Main Concern ◽  
Assay Optimization ◽  
Screening Platform

In recent years, bacterial infections have become a main concern following the spread of antimicrobial resistance. In addition, bacterial biofilms are known for their high tolerance to antimicrobials and they are regarded as a main cause of recalcitrant infections in humans. Many efforts have been deployed in order to find new antibacterial therapeutic options and the high-throughput screening (HTS) of large libraries of compounds is one of the utilized strategies. However, HTS efforts for anti-biofilm discovery remain uncommon. Here, we miniaturized a 96-well plate (96WP) screening platform, into a 384-well plate (384WP) format, based on a sequential viability and biomass measurements for the assessment of anti-biofilm activity. During the assay optimization process, different parameters were evaluated while using Staphylococcus aureus and Pseudomonas aeruginosa as the bacterial models. We compared the performance of the optimized 384WP platform to our previously established 96WP-based platform by carrying out a pilot screening of 100 compounds, followed by the screening of a library of 2000 compounds to identify new repurposed anti-biofilm agents. Our results show that the optimized 384WP platform is well-suited for screening purposes, allowing for the rapid screening of a higher number of compounds in a run in a reliable manner.

scholarly journals Competitive adherence as a mechanism of bacterial interference

1983 ◽  
Vol 29 (6) ◽  
pp. 700-703 ◽  
Author(s):  
Debra Jan Bibel ◽  
Raza Aly ◽  
Charlene Bayles ◽  
Walter G. Strauss ◽  
Henry R. Shinefield ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Host Cell ◽  
Virulent Strain ◽  
Host Cells ◽  
Aureus Strain ◽  
Attachment Sites ◽  
Specific Attachment ◽  
Mucosal Cells ◽  
Bacterial Interference

To determine whether competition among bacteria for specific attachment sites on host cells can explain bacterial interference, Staphylococcus aureus strain 502A was tested in turn against two different nasal coryneforms, a strain of Pseudomonas aeruginosa, and a virulent strain of S. aureus, all in the presence of nasal mucosal cells. Particularly examined was the influence of sequence in which bacteria were presented to the nasal cells in comparison with initial mixtures and individual suspensions. Results paralleled those observed in clinical prophylaxis: the bacterium first to adhere to the epithelial cells was able, under uniform conditions, to interfere with the colonization of subsequently added bacteria. Secondary adherence was not eliminated but substantially reduced, and was probably related to steric blockage by the initial colonizer and its particular ability to dissociate from the host cell.

scholarly journals De Novo Purine Biosynthesis Is Required for Intracellular Growth of Staphylococcus aureus and for the Hypervirulence Phenotype of a purR Mutant

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Mariya I. Goncheva ◽  
Ronald S. Flannagan ◽  
David E. Heinrichs
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Metabolic Regulation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Mammalian Host ◽  
Cell Binding ◽  
Intracellular Growth ◽  
Content Type ◽  
De Novo Purine Biosynthesis

ABSTRACT Staphylococcus aureus is a noted human and animal pathogen. Despite decades of research on this important bacterium, there are still many unanswered questions regarding the pathogenic mechanisms it uses to infect the mammalian host. This can be attributed to it possessing a plethora of virulence factors and complex virulence factor and metabolic regulation. PurR, the purine biosynthesis regulator, was recently also shown to regulate virulence factors in S. aureus, and mutations in purR result in derepression of fibronectin binding proteins (FnBPs) and extracellular toxins, required for a so-called hypervirulent phenotype. Here, we show that hypervirulent strains containing purR mutations can be attenuated with the addition of purine biosynthesis mutations, implicating the necessity for de novo purine biosynthesis in this phenotype and indicating that S. aureus in the mammalian host experiences purine limitation. Using cell culture, we showed that while purR mutants are not altered in epithelial cell binding, compared to that of wild-type (WT) S. aureus, purR mutants have enhanced invasion of these nonprofessional phagocytes, consistent with the requirement of FnBPs for invasion of these cells. This correlates with purR mutants having increased transcription of fnb genes, resulting in higher levels of surface-exposed FnBPs to promote invasion. These data provide important contributions to our understanding of how the pathogenesis of S. aureus is affected by sensing of purine levels during infection of the mammalian host.

scholarly journals Organoselenium Coating on Cellulose Inhibits the Formation of Biofilms by Pseudomonas aeruginosa and Staphylococcus aureus

2009 ◽  
Vol 75 (11) ◽  
pp. 3586-3592 ◽  
Author(s):  
Phat L. Tran ◽  
Adrienne A. Hammond ◽  
Thomas Mosley ◽  
Janette Cortez ◽  
Tracy Gray ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Bacterial Attachment ◽  
Wound Dressings ◽  
Aqueous Environment ◽  
Burn Victims ◽  
Surgical Wounds

ABSTRACT Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.

scholarly journals Pseudomonas aeruginosa GroEL Stimulates Production of PTX3 by Activating the NF-κB Pathway and Simultaneously Downregulating MicroRNA-9

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Heesung Shin ◽  
Jisu Jeon ◽  
Jung-Hoon Lee ◽  
Shouguang Jin ◽  
Un-Hwan Ha
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Therapeutic Potential ◽  
Host Cells ◽  
Soluble Form ◽  
Heat Shock Protein 60 ◽  
Toll Like Receptor 4 ◽  
Content Type ◽  
Host Immune Responses ◽  
Recognition Receptor

ABSTRACT As one of the first lines of host defense, monocytes play important roles in clearing infected microbes. The defensive response is triggered by recognition of diverse microbial moieties, including released factors, which modulate host immune responses to establish a harsh environment for clinically important bacterial pathogens. In this study, we found that the expression of PTX3, a soluble form of pattern recognition receptor, was induced by infection with live Pseudomonas aeruginosa or treatment of cells with its supernatant. P. aeruginosa GroEL, a homolog of heat shock protein 60, was identified as one of the factors responsible for inducing the expression of PTX3 in host cells. GroEL induced PTX3 expression by activating the Toll-like receptor 4 (TLR4)-dependent pathway via nuclear factor-kappa B (NF-κB), while simultaneously inhibiting expression of microRNA-9, which targets the PTX3 transcript. Finally, by acting as an opsonin, GroEL-induced PTX3 promoted the association and phagocytosis of Staphylococcus aureus into macrophages. These data suggest that the host defensive environment is supported by the production of PTX3 in response to GroEL, which thus has therapeutic potential for clearance of bacterial infections.

scholarly journals Methionine Limitation Impairs Pathogen Expansion and Biofilm Formation Capacity

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
A. Jochim ◽  
T. Shi ◽  
D. Belikova ◽  
S. Schwarz ◽  
A. Peschel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Human Serum ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Biosynthesis Pathway ◽  
Methionine Biosynthesis ◽  
Content Type

ABSTRACTMultidrug-resistant bacterial pathogens are becoming increasingly prevalent, and novel strategies to treat bacterial infections caused by these organisms are desperately needed. Bacterial central metabolism is crucial for catabolic processes and provides precursors for anabolic pathways, such as the biosynthesis of essential biomolecules like amino acids or vitamins. However, most essential pathways are not regarded as good targets for antibiotic therapy since their products might be acquired from the environment. This issue raises doubts about the essentiality of such targets during infection. A putative target in bacterial anabolism is the methionine biosynthesis pathway. In contrast to humans, almost all bacteria carry methionine biosynthesis pathways which have often been suggested as putative targets for novel anti-infectives. While the growth of methionine auxotrophic strains can be stimulated by exogenous methionine, the extracellular concentrations required by most bacterial species are unknown. Furthermore, several phenotypic characteristics of methionine auxotrophs are only partly reversed by exogenous methionine. We investigated methionine auxotrophic mutants ofStaphylococcus aureus,Pseudomonas aeruginosa, andEscherichia coli(all differing in methionine biosynthesis enzymes) and found that each needed concentrations of exogenous methionine far exceeding that reported for human serum (∼30 µM). Accordingly, these methionine auxotrophs showed a reduced ability to proliferate in human serum. Additionally,S. aureusandP. aeruginosamethionine auxotrophs were significantly impaired in their ability to form and maintain biofilms. Altogether, our data show intrinsic defects of methionine auxotrophs. This result suggests that the pathway should be considered for further studies validating the therapeutic potential of inhibitors.IMPORTANCENew antibiotics that attack novel targets are needed to circumvent widespread resistance to conventional drugs. Bacterial anabolic pathways, such as the enzymes for biosynthesis of the essential amino acid methionine, have been proposed as potential targets. However, the eligibility of enzymes in these pathways as drug targets is unclear because metabolites might be acquired from the environment to overcome inhibition. We investigated the nutritional needs of methionine auxotrophs of the pathogensStaphylococcus aureus,Pseudomonas aeruginosa, andEscherichia coli. We found that each auxotrophic strain retained a growth disadvantage at methionine concentrations mimicking those availablein vivoand showed that biofilm biomass was strongly influenced by endogenous methionine biosynthesis. Our experiments suggest that inhibition of the methionine biosynthesis pathway has deleterious effects even in the presence of external methionine. Therefore, additional efforts to validate the effects of methionine biosynthesis inhibitorsin vivoare warranted.

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