scholarly journals A bacterial "shield and sword": A previously uncharacterized two-component system protects uropathogenic Escherichia coli from host-derived oxidative insults and promotes hemolysin-mediated host cell pyroptosis

2021 ◽  
Author(s):  
Hongwei Gu ◽  
Xuwang Cai ◽  
Xinyang Zhang ◽  
Jie Luo ◽  
Xiaoyang Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Bacterial Pathogen ◽  
Methionine Sulfoxide ◽  
Uropathogenic Escherichia Coli ◽  
Methionine Sulfoxide Reductase ◽  
Renal Epithelial Cell ◽  
Two Component ◽  
Tract Infections

Uropathogenic Escherichia coli (UPEC) deploys an array of virulence factors to successfully establish urinary tract infections. Coordinated expression of these various virulence factors is critical for UPEC's overall fitness in the host. Two-component signaling systems (TCSs) are a major mechanism by which bacteria sense environmental cues and initiate adaptive responses. Here, we report a previously uncharacterized TCS encoded on a pathogenicity island in UPEC that directly activates the expression of a putative methionine sulfoxide reductase system (C3566/C3567) and a pore-forming hemolysin in response to host-derived hydrogen peroxide (H2O2) exposure. The TCS increases UPEC resistance to H2O2 in vitro and survival in macrophages in tissue culture via C3566/C3567. Additionally, the TCS mediates hemolysin-induced renal epithelial cell and macrophage death via a pyroptosis pathway. Taken together, our data suggest a paradigm in which this signal transduction system coordinates both bacterial pathogen defensive and offensive traits in the presence of host-derived signals.

scholarly journals HypVW is an HOCl-Sensing Two Component System in Escherichia coli

2021 ◽  
Author(s):  
Sara El Hajj ◽  
Camille Henry ◽  
Alexandra Vergnes ◽  
Laurent Loiseau ◽  
Brasseur Gael ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hypochlorous Acid ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductase ◽  
Bacterial Cells ◽  
E Coli ◽  
Two Component ◽  
Redox Switch ◽  
Two Component Systems ◽  
Methionine Residues

Two component systems (TCS) are signalling pathways that allow bacterial cells to sense, respond and adapt to fluctuating environments. Among the classical TCS of Escherichia coli, YedVW has been recently showed to be involved in the regulation of msrPQ, encoding for the periplasmic methionine sulfoxide reductase system. In this study, we demonstrate that hypochlorous acid (HOCl) induces the expression of msrPQ in a YedVW dependant manner, whereas H2O2, NO and paraquat (a superoxide generator) do not. Therefore, YedV appears to be an HOCl-sensing histidine kinase. Based on this finding, we proposed to rename this system HypVW.  Moreover, using a directed mutagenesis approach, we show that Met residues located in the periplasmic loop of HypV (formerly YedV) are important for its activity. Given that HOCl oxidizes preferentially Met residues, we bring evidences that HypV could be activated via the reversible oxidation of its methionine residues, thus conferring to MsrPQ a role in switching HypVW off. Based on these results, we propose that the activation of HypV by HOCl could occur through a Met redox switch. HypVW appears to be the first characterized TCS able to detect HOCl in E. coli. This study represents an important step in understanding the mechanisms of reactive chlorine species resistance in prokaryotes.

HprSR is a Reactive Chlorine Species-Sensing, Two-Component System in Escherichia coli

2021 ◽  
Author(s):  
Sara El Hajj ◽  
Camille Henry ◽  
Camille Andrieu ◽  
Alexandra Vergnes ◽  
Laurent Loiseau ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hypochlorous Acid ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductase ◽  
Repair System ◽  
Bacterial Cells ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Redox Switch

Two-component systems (TCS) are signalling pathways that allow bacterial cells to sense, respond and adapt to fluctuating environments. Among the classical TCS of Escherichia coli , HprSR has recently been shown to be involved in the regulation of msrPQ , which encodes the periplasmic methionine sulfoxide reductase system. In this study, we demonstrate that hypochlorous acid (HOCl) induces the expression of msrPQ in an HprSR-dependant manner, whereas H 2 O 2 , NO and paraquat (a superoxide generator) do not. Therefore, HprS appears to be an HOCl-sensing histidine kinase. Using a directed mutagenesis approach, we show that Met residues located in the periplasmic loop of HprS are important for its activity: as HOCl preferentially oxidizes Met residues, we provide evidence that HprS could be activated via the reversible oxidation of its methionine residues, meaning that MsrPQ plays a role in switching HprSR off. We propose that the activation of HprS by HOCl could occur through a Met redox switch. HprSR appears to be the first characterized TCS able to detect reactive chlorine species (RCS) in E. coli . This study represents an important step towards understanding the mechanisms of RCS resistance in prokaryotes. IMPORTANCE Understanding how bacteria respond to oxidative stress at the molecular level is crucial in the fight against pathogens. HOCl is one of the most potent industrial and physiological microbiocidal oxidants. Therefore bacteria have developed counterstrategies to survive HOCl-induced stress. Over the last decade, important insights into these bacterial protection factors have been obtained. Our work establishes HprSR as a reactive chlorine species-sensing, two-component system in Escherichia coli MG1655, which regulates the expression of MsrPQ, a repair system for HOCl-oxidized proteins. Moreover we provide evidence suggesting that HOCl could activate HprS through a methionine redox switch.

scholarly journals A Conserved PapB Family Member, TosR, Regulates Expression of the Uropathogenic Escherichia coli RTX Nonfimbrial Adhesin TosA while Conserved LuxR Family Members TosE and TosF Suppress Motility

2014 ◽  
Vol 82 (9) ◽  
pp. 3644-3656 ◽  
Author(s):  
Michael D. Engstrom ◽  
Christopher J. Alteri ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Upper Urinary Tract ◽  
Host Cells ◽  
Promoter Regions ◽  
Content Type ◽  
Tract Infections

ABSTRACTA heterogeneous subset of extraintestinal pathogenicEscherichia coli(ExPEC) strains, referred to as uropathogenicE. coli(UPEC), causes most uncomplicated urinary tract infections. However, no core set of virulence factors exists among UPEC strains. Instead, the focus of the analysis of urovirulence has shifted to studying broad classes of virulence factors and the interactions between them. For example, the RTX nonfimbrial adhesin TosA mediates adherence to host cells derived from the upper urinary tract. The associatedtosoperon is well expressedin vivobut poorly expressedin vitroand encodes TosCBD, a predicted type 1 secretion system. TosR and TosEF are PapB and LuxR family transcription factors, respectively; however, no role has been assigned to these potential regulators. Thus, the focus of this study was to determine how TosR and TosEF regulatetosAand affect the reciprocal expression of adhesins and flagella. Among a collection of sequenced UPEC strains, 32% (101/317) were found to encode TosA, and nearly all strains (91% [92/101]) simultaneously carried the putative regulatory genes. Deletion oftosRalleviatestosArepression. Thetospromoter was localized upstream oftosRusing transcriptional fusions of putative promoter regions withlacZ. TosR binds to this region, affecting a gel shift. A 100-bp fragment 220 to 319 bp upstream oftosRinhibits binding, suggesting localization of the TosR binding site. TosEF, on the other hand, downmodulate motility when overexpressed by preventing the expression offliC, encoding flagellin. Deletion oftosEFincreased motility. Thus, we present an additional example of the reciprocal control of adherence and motility.

scholarly journals Urothelial Cultures Support Intracellular Bacterial Community Formation by Uropathogenic Escherichia coli

2009 ◽  
Vol 77 (7) ◽  
pp. 2762-2772 ◽  
Author(s):  
Ruth E. Berry ◽  
David J. Klumpp ◽  
Anthony J. Schaeffer
Keyword(s):  
Escherichia Coli ◽  
Fluorescence Microscopy ◽  
Virulence Factors ◽  
Biochemical Characterization ◽  
Iron Acquisition ◽  
Urothelial Cells ◽  
Bacterial Aggregates ◽  
Tract Infections ◽  
Intracellular Proliferation

ABSTRACT Uropathogenic Escherichia coli (UPEC) causes most community-acquired and nosocomial urinary tract infections (UTI). In a mouse model of UTI, UPEC invades superficial bladder cells and proliferates rapidly, forming biofilm-like structures called intracellular bacterial communities (IBCs). Using a gentamicin protection assay and fluorescence microscopy, we developed an in vitro model for studying UPEC proliferation within immortalized human urothelial cells. By pharmacologic manipulation of urothelial cells with the cholesterol-sequestering drug filipin, numbers of intracellular UPEC CFU increased 8 h and 24 h postinfection relative to untreated cultures. Enhanced UPEC intracellular proliferation required that the urothelial cells, but not the bacteria, be filipin treated prior to infection. However, neither UPEC frequency of invasion nor early intracellular trafficking events to a Lamp1-positive compartment were modulated by filipin. Upon inspection by fluorescence microscopy, cultures with enhanced UPEC intracellular proliferation exhibited large, dense bacterial aggregates within cells that resembled IBCs but were contained with Lamp1-positive vacuoles. While an isogenic fimH mutant was capable of forming these IBC-like structures, the mutant formed significantly fewer than wild-type UPEC. Similar to IBCs, expression of E. coli iron acquisition systems was upregulated by intracellular UPEC. Expression of other putative virulence factors, including hlyA, cnf1, fliC, kpsD, and the biofilm adhesin yfaL also increased, while expression of fimA decreased and that of flu did not change. These results indicate that UPEC differentially regulates virulence factors in the intracellular environment. Thus, immortalized urothelial cultures that recapitulate IBC formation in vitro represent a novel system for the molecular and biochemical characterization of the UPEC intracellular life cycle.

scholarly journals FNR Regulates Expression of Important Virulence Factors Contributing to Pathogenicity of Uropathogenic Escherichia coli

2014 ◽  
Vol 82 (12) ◽  
pp. 5086-5098 ◽  
Author(s):  
Nicolle L. Barbieri ◽  
Bryon Nicholson ◽  
Ashraf Hussein ◽  
Wentong Cai ◽  
Yvonne M. Wannemuehler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Uropathogenic Escherichia Coli ◽  
Type I ◽  
Wild Type ◽  
Global Regulator ◽  
Content Type ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) is responsible for the majority of urinary tract infections (UTIs), which are some of the world's most common bacterial infections of humans. Here, we examined the role of FNR (fumarate andnitratereduction), a well-known global regulator, in the pathogenesis of UPEC infections. We constructed anfnrdeletion mutant of UPEC CFT073 and compared it to the wild type for changes in virulence, adherence, invasion, and expression of key virulence factors. Compared to the wild type, thefnrmutant was highly attenuated in the mouse model of human UTI and showed severe defects in adherence to and invasion of bladder and kidney epithelial cells. Our results showed that FNR regulates motility and multiple virulence factors, including expression of type I and P fimbriae, modulation of hemolysin expression, and expression of a novel pathogenicity island involved in α-ketoglutarate metabolism under anaerobic conditions. Our results demonstrate that FNR is a key global regulator of UPEC virulence and controls expression of important virulence factors that contribute to UPEC pathogenicity.

scholarly journals Synergistic Effect of Propolis and Antibiotics on Uropathogenic Escherichia coli

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 739
Author(s):  
Jean-Philippe Lavigne ◽  
Jérémy Ranfaing ◽  
Catherine Dunyach-Rémy ◽  
Albert Sotto
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Uropathogenic Escherichia Coli ◽  
Resistant Bacteria ◽  
Minimal Inhibitory Concentrations ◽  
Tract Infections

Urinary tract infections (UTIs) are the most common bacterial infections around the world. Uropathogenic Escherichia coli (UPEC) is among the main pathogens isolated in UTIs. The rate of UPEC with high resistance towards antibiotics and multidrug-resistant bacteria have increased dramatically and conduct to the difficulty to treat UTIs. Due to the rarefaction of new antibiotics molecules, new alternative strategies must be evaluated. Since many years, propolis has demonstrated an interesting antibacterial activity against E. coli. Here, we evaluated its activity added to antibiotics on a panel of UPEC with different resistance mechanisms. Minimal inhibitory concentrations (MICs) and time–kill curves of fosfomycin, ceftriaxone, ertapenem and ofloxacin, with and without propolis, were determined. Significant diminution of the MICs was observed using ceftriaxone or ofloxacin + propolis. Propolis alone had a bacteriostatic activity with time-dependent effect against UPEC. The addition of this nutraceutical improved the effect of all the antibiotics evaluated (except fosfomycin) and showed a synergistic bactericidal effect (fractional inhibitory concentrations index ≤ 0.5 and a decrease ≥ 2 log CFU/mL for the combination of propolis plus antibiotics compared with the antibiotic alone). Propolis is able to restore in vitro antibiotic susceptibility when added to antibiotics against UPEC. This study showed that propolis could enhance the efficiency of antibiotics used in UTIs and could represent an alternative solution.

scholarly journals Is it Worth Combining Solidago virgaurea Extract and Antibiotics against Uropathogenic Escherichia coli rods? An In Vitro Model Study

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 573
Author(s):  
Dorota Wojnicz ◽  
Dorota Tichaczek-Goska ◽  
Michał Gleńsk ◽  
Andrzej B. Hendrich
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Properties ◽  
Antagonistic Activity ◽  
Viable Count ◽  
Uropathogenic Escherichia Coli ◽  
Model Study ◽  
Solidago Virgaurea ◽  
Vitro Model ◽  
Tract Infections

European goldenrod (Solidago virgaurea L.) has long been applied in traditional medicine and recommended in the prophylaxis of urinary tract infections (UTIs). However, research describing the antibacterial properties of goldenrod is very limited. Therefore, the aim of the study was to determine the effect of S. virgaurea extract on the survival and biofilm formation of uropathogenic Escherichia coli. The interactions between the goldenrod extract and antibiotics used in UTIs were established. The influence of the extract on the duration of the post-antibiotic effects (PAE) and post-antibiotic sub-MIC effects (PASME) of amikacin and ciprofloxacin were determined. Extract composition was analyzed using coupled UHPLC/MS and the spectrophotometric method. The survival of bacteria was established using the serial dilution assay. The crystal violet assay for biofilm quantification was also used. PAE and PASME were investigated using the viable count method. The obtained results indicate that S. virgaurea extract limits the survival of planktonic forms of bacteria and reduces 24-h biofilm. However, the combination of S. virgaurea extract with antibiotics weakens their antibacterial activity and shortens the duration of PAE and PASME. Therefore, when deciding to use a combination of S. virgaurea extract and amikacin/ciprofloxacin, it is necessary to take into account their antagonistic activity.

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