scholarly journals Cross Talk between MarR-Like Transcription Factors Coordinates the Regulation of Motility in UropathogenicEscherichia coli

2018 ◽  
Vol 86 (12) ◽  
Author(s):  
Courtney L. Luterbach ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Cross Talk ◽  
Flagellar Gene ◽  
Upec Strain ◽  
Content Type ◽  
Dose Effects ◽  
Regulator Genes ◽  
Strain Cft073 ◽  
Tract Infections ◽  
The Impact

ABSTRACTThe MarR-like protein PapX represses the transcription of the flagellar master regulator genesflhDCin uropathogenicEscherichia coli(UPEC), the primary cause of uncomplicated urinary tract infections (UTIs). PapX is encoded by thepapoperon, which also encodes the adherence factors termed P fimbriae. Both adherence and motility are critical for productive colonization of the urinary tract. However, the mechanisms involved in coordinating the transition between adherence and motility are not well characterized. UPEC strain CFT073 carries bothpapXand a homolog,focX, located in thefocoperon encoding F1C fimbriae. In this study, we characterized the dose effects of “X” genes on flagellar gene expression and cross talk betweenfocXandpapX. We found that both FocX and PapX repressflhDtranscription. However, we determined that the ΔpapXmutant was hypermotile, while the loss offocXdid not affect motility. We further investigated this phenotype and found that FocX functions as a repressor ofpapX. Additionally, we identified a proximal independent promoter upstream of bothfocXandpapXand assessed the expression offocXandpapXduring culture in human urine and on LB agar plates compared to LB medium. Finally, we characterized the contributions of PapX and FocX to fitness in the ascending murine model of UTI and observed a subtle, but not statistically significant, fitness defect in colonization of the kidneys. Altogether, these results expand our understanding of the impact of carrying multiple X genes on the coordinated regulation of motility and adherence in UPEC.

scholarly journals Inhibition of Escherichia coli CFT073fliCExpression and Motility by Cranberry Materials

2011 ◽  
Vol 77 (19) ◽  
pp. 6852-6857 ◽  
Author(s):  
Gabriela Hidalgo ◽  
Michelle Chan ◽  
Nathalie Tufenkji
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Upper Urinary Tract ◽  
Upec Strain ◽  
Microscopy Imaging ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Strain Cft073 ◽  
Tract Infections

ABSTRACTIn humans, uropathogenicEscherichia coli(UPEC) is the most common etiological agent of uncomplicated urinary tract infections (UTIs). Cranberry extracts have been linked to the prevention of UTIs for over a century; however, a mechanistic understanding of the way in which cranberry derivatives prevent bacterial infection is still lacking. In this study, we used afliC-luxreporter as well as quantitative reverse transcription-PCR to demonstrate that when UPEC strain CFT073 was grown or exposed to dehydrated, crushed cranberries or to purified cranberry-derived proanthocyanidins (cPACs), expression of the flagellin gene (fliC) was inhibited. In agreement with these results, transmission electron microscopy imaging of bacteria grown in the presence of cranberry materials revealed fewer flagella than those in bacteria grown under control conditions. Furthermore, we showed that swimming and swarming motilities were hindered when bacteria were grown in the presence of the cranberry compounds. Because flagellum-mediated motility has been suggested to enable UPEC to disseminate to the upper urinary tract, we propose that inhibition of flagellum-mediated motility might be a key mechanism by which cPACs prevent UTIs. This is the first report to show that cranberry compounds inhibit UPEC motility via downregulation of thefliCgene. Further studies are required to establish whether these inhibitors play a rolein vivo.

scholarly journals RpoS Contributes to Phagocyte Oxidase-Mediated Stress Resistance during Urinary Tract Infection by Escherichia coli CFT073

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Andrew J. Hryckowian ◽  
Rodney A. Welch
Keyword(s):  
Oxidative Stress ◽  
Urinary Tract ◽  
Wild Type ◽  
Upec Strain ◽  
Content Type ◽  
General Stress Response ◽  
E Coli ◽  
Phagocyte Oxidase ◽  
Strain Cft073 ◽  
K 12

ABSTRACTUropathogenicEscherichia coli(UPEC) is the most common causative agent of community-acquired urinary tract infection (UTI). In order to cause UTI, UPEC must endure stresses ranging from nutrient limitation to host immune components. RpoS (σS), the general stress response sigma factor, directs gene expression under a variety of inhibitory conditions. Our study ofrpoSin UPEC strain CFT073 began after we discovered anrpoS-frameshift mutation in one of our laboratory stocks of “wild-type” CFT073. We demonstrate that anrpoS-deletion mutation in CFT073 leads to a colonization defect during UTI of CBA/J mice at 48 hours postinfection (hpi). There is no difference between the growth rates of CFT073 and CFT073rpoSin urine. This indicates thatrpoSis needed for replication and survival in the host rather than being needed to address limitations imposed by urine nutrients. Consistent with previous observations inE. coliK-12, CFT073rpoSis more sensitive to oxidative stress than the wild type. We demonstrate that peroxide levels are elevated in voided urine from CFT073-infected mice compared to urine from mock-infected mice, which supports the notion that oxidative stress is generated by the host in response to UPEC. In mice that lack phagocyte oxidase, the enzyme complex expressed by phagocytes that produces superoxide, the competitive defect of CFT073rpoSin bladder colonization is lost. These results demonstrate that σSis important for UPEC survival under conditions of phagocyte oxidase-generated stress during UTI. Though σSaffects the pathogenesis of other bacterial species, this is the first work that directly implicates σSas important for UPEC pathogenesis.IMPORTANCEUPEC must cope with a variety of stressful conditions in the urinary tract during infection. RpoS (σS), the general stress response sigma factor, is known to direct the expression of many genes under a variety of stressful conditions in laboratory-adaptedE. coliK-12. Here, we show that σSis needed by the model UPEC strain CFT073 to cope with oxidative stress provided by phagocytes during infection. These findings represent the first report that implicates σSin the fitness of UPEC during infection and support the idea of the need for a better understanding of the effects of this global regulator of gene expression during UTI.

scholarly journals Decreased Expression of Type 1 Fimbriae by apstMutant of Uropathogenic Escherichia coli Reduces Urinary Tract Infection

2012 ◽  
Vol 80 (8) ◽  
pp. 2802-2815 ◽  
Author(s):  
Sébastien Crépin ◽  
Sébastien Houle ◽  
Marie-Ève Charbonneau ◽  
Michaël Mourez ◽  
Josée Harel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Bacterial Virulence ◽  
Pho Regulon ◽  
Upec Strain ◽  
Content Type ◽  
Type 1 Fimbriae ◽  
Genes Encoding ◽  
Tract Infections

ABSTRACTThepstSCAB-phoUoperon encodes the phosphate-specific transport system (Pst). Loss of Pst constitutively activates the Pho regulon and decreases bacterial virulence. However, specific mechanisms underlying decreased bacterial virulence through inactivation of Pst are poorly understood. In uropathogenicEscherichia coli(UPEC) strain CFT073, inactivation ofpstdecreased urinary tract colonization in CBA/J mice. Thepstmutant was deficient in production of type 1 fimbriae and showed decreased expression of thefimAstructural gene which correlated with differential expression of thefimB,fimE,ipuA, andipbAgenes, encoding recombinases, mediating inversion of thefimpromoter. The role offimdownregulation in attenuation of thepstmutant was confirmed using afimphase-locked-on derivative, which demonstrated a significant gain in virulence. In addition, thepstmutant was less able to invade human bladder epithelial cells. Since type 1 fimbriae contribute to UPEC virulence by promoting colonization and invasion of bladder cells, the reduced bladder colonization by thepstmutant is predominantly attributed to downregulation of these fimbriae. Elucidation of mechanisms mediating the control of type 1 fimbriae through activation of the Pho regulon in UPEC may open new avenues for therapeutics or prophylactics against urinary tract infections.

scholarly journals Epigenetic Mechanisms Regulate Innate Immunity against Uropathogenic and Commensal-Like Escherichia coli in the Surrogate Insect Model Galleria mellonella

2017 ◽  
Vol 85 (10) ◽  
Author(s):  
Miriam Heitmueller ◽  
André Billion ◽  
Ulrich Dobrindt ◽  
Andreas Vilcinskas ◽  
Krishnendu Mukherjee
Keyword(s):  
Escherichia Coli ◽  
Innate Immunity ◽  
Urinary Tract ◽  
Histone Acetylation ◽  
Galleria Mellonella ◽  
Epigenetic Mechanisms ◽  
Upec Strain ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Innate-immunity-related genes in humans are activated during urinary tract infections (UTIs) caused by pathogenic strains of Escherichia coli but are suppressed by commensals. Epigenetic mechanisms play a pivotal role in the regulation of gene expression in response to environmental stimuli. To determine whether epigenetic mechanisms can explain the different behaviors of pathogenic and commensal bacteria, we infected larvae of the greater wax moth, Galleria mellonella, a widely used model insect host, with a uropathogenic E. coli (UPEC) strain that causes symptomatic UTIs in humans or a commensal-like strain that causes asymptomatic bacteriuria (ABU). Infection with the UPEC strain (CFT073) was more lethal to larvae than infection with the attenuated ABU strain (83972) due to the recognition of each strain by different Toll-like receptors, ultimately leading to differential DNA/RNA methylation and histone acetylation. We used next-generation sequencing and reverse transcription (RT)-PCR to correlate epigenetic changes with the induction of innate-immunity-related genes. Transcriptomic analysis of G. mellonella larvae infected with E. coli strains CFT073 and 83972 revealed strain-specific variations in the class and expression levels of genes encoding antimicrobial peptides, cytokines, and enzymes controlling DNA methylation and histone acetylation. Our results provide evidence for the differential epigenetic regulation of transcriptional reprogramming by UPEC and ABU strains of E. coli in G. mellonella larvae, which may be relevant to understanding the different behaviors of these bacterial strains in the human urinary tract.

scholarly journals Adaptation of Arginine Synthesis among Uropathogenic Branches of the Escherichia coli Phylogeny Reveals Adjustment to the Urinary Tract Habitat

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Michael E. Hibbing ◽  
Karen W. Dodson ◽  
Vasilios Kalas ◽  
Swaine L. Chen ◽  
Scott J. Hultgren
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Inoculum Size ◽  
Specific Gene ◽  
Population Bottlenecks ◽  
Founder Population ◽  
Upec Strain ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Urinary tract infections (UTIs) are predominantly caused by uropathogenic Escherichia coli (UPEC). UPEC pathogenesis requires passage through a severe population bottleneck involving intracellular bacterial communities (IBCs) that are clonal expansions of a single invading UPEC bacterium in a urothelial superficial facet cell. IBCs occur only during acute pathogenesis. The bacteria in IBCs form the founder population that develops into persistent extracellular infections. Only a small fraction of UPEC organisms proceed through the IBC cycle, regardless of the inoculum size. This dramatic reduction in population size precludes the utility of genomic mutagenesis technologies for identifying genes important for persistence. To circumvent this bottleneck, we previously identified 29 positively selected genes (PSGs) within UPEC and hypothesized that they contribute to virulence. Here, we show that 8 of these 29 PSGs are required for fitness during persistent bacteriuria. Conversely, 7/8 of these PSG mutants showed essentially no phenotype in acute UTI. Deletion of the PSG argI leads to arginine auxotrophy. Relative to the other arg genes, argI in the B2 clade (which comprises most UPEC strains) of E. coli has diverged from argI in other E. coli clades. Replacement of argI in a UPEC strain with a non-UPEC argI allele complemented the arginine auxotrophy but not the persistent bacteriuria defect, showing that the UPEC argI allele contributes to persistent infection. These results highlight the complex roles of metabolic pathways during infection and demonstrate that evolutionary approaches can identify infection-specific gene functions downstream of population bottlenecks, shedding light on virulence and the genetic evolution of pathogenesis. IMPORTANCE Uropathogenic Escherichia coli (UPEC) is the most common cause of human urinary tract infection (UTI). Population bottlenecks during early stages of UTI make high-throughput screens impractical for understanding clinically important later stages of UTI, such as persistence and recurrence. As UPEC is hypothesized to be adapted to these later pathogenic stages, we previously identified 29 genes evolving under positive selection in UPEC. Here, we found that 8 of these genes, including argI (which is involved in arginine biosynthesis), are important for persistence in a mouse model of UTI. Deletion of argI and other arginine synthesis genes resulted in (i) arginine auxotrophy and (ii) defects in persistent UTI. Replacement of a B2 clade argI with a non-B2 clade argI complemented arginine auxotrophy, but the resulting strain remained attenuated in its ability to cause persistent bacteriuria. Thus, argI may have a second function during UTI that is not related to simple arginine synthesis. This study demonstrates how variation in metabolic genes can impact virulence and provides insight into the mechanisms and evolution of bacterial virulence.

scholarly journals Role of Motility in the Colonization of Uropathogenic Escherichia coli in the Urinary Tract

2005 ◽  
Vol 73 (11) ◽  
pp. 7644-7656 ◽  
Author(s):  
M. Chelsea Lane ◽  
Virginia Lockatell ◽  
Greta Monterosso ◽  
Daniel Lamphier ◽  
Julia Weinert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Wild Type Strain ◽  
Uropathogenic Escherichia Coli ◽  
Wild Type ◽  
Upec Strain ◽  
Host Immune Responses ◽  
Strain Cft073 ◽  
Tract Infections

ABSTRACT Uropathogenic Escherichia coli (UPEC) causes most uncomplicated urinary tract infections (UTIs) in humans. Flagellum-mediated motility and chemotaxis have been suggested to contribute to virulence by enabling UPEC to escape host immune responses and disperse to new sites within the urinary tract. To evaluate their contribution to virulence, six separate flagellar mutations were constructed in UPEC strain CFT073. The mutants constructed were shown to have four different flagellar phenotypes: fliA and fliC mutants do not produce flagella; the flgM mutant has similar levels of extracellular flagellin as the wild type but exhibits less motility than the wild type; the motAB mutant is nonmotile; and the cheW and cheY mutants are motile but nonchemotactic. Virulence was assessed by transurethral independent challenges and cochallenges of CBA mice with the wild type and each mutant. CFU/ml of urine or CFU/g bladder or kidney was determined 3 days postinoculation for the independent challenges and at 6, 16, 48, 60, and 72 h postinoculation for the cochallenges. While these mutants colonized the urinary tract during independent challenge, each of the mutants was outcompeted by the wild-type strain to various degrees at specific time points during cochallenge. Altogether, these results suggest that flagella and flagellum-mediated motility/chemotaxis may not be absolutely required for virulence but that these traits contribute to the fitness of UPEC and therefore significantly enhance the pathogenesis of UTIs caused by UPEC.

scholarly journals Identification ofIn Vivo-Induced Antigens Including an RTX Family Exoprotein Required for Uropathogenic Escherichia coli Virulence

2011 ◽  
Vol 79 (6) ◽  
pp. 2335-2344 ◽  
Author(s):  
Patrick D. Vigil ◽  
Christopher J. Alteri ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Iron Acquisition ◽  
Expression Library ◽  
Upec Strain ◽  
Infected Female ◽  
Content Type ◽  
Strain Cft073 ◽  
Tract Infections

ABSTRACTUncomplicated urinary tract infections (UTI) are caused most commonly by uropathogenicEscherichia coli(UPEC). Whole-genome screening approaches, including transcriptomic, proteomic, and signature-tagged mutagenesis, have shown that UPEC highly expresses or requires genes for translational machinery, capsule, lipopolysaccharide, type 1 fimbriae, and iron acquisition systems during UTI. To identify additional genes expressed by UPEC during UTI, an immunoscreening approach termedin vivo-induced antigen technology (IVIAT) was employed to identify antigens produced during experimental infection that are not produced duringin vitroculture. An inducible protein expression library, constructed from genomic DNA isolated from UPEC strain CFT073, was screened using exhaustively adsorbed pooled sera from 20 chronically infected female CBA/J mice. Using this approach, we identified 93 antigens induced by UPECin vivo. A representative subset of these genes was tested by quantitative PCR for expression by CFT073in vivoand during growth in human urine or LB mediumin vitro;proWX,narJI,lolA,lolD,tosA(upxA), c2432,katG,ydhX,kpsS, andyddQwere poorly expressedin vitrobut highly expressedin vivo. Of these,tosA, a gene encoding a predicted repeat-in-toxin family member, was expressed exclusively during UTI. Deletion oftosAin UPEC strain CFT073 resulted in significant attenuation in bladder and kidney infections during ascending UTI. By screening forin vivo-induced antigens, we identified a novel UPEC virulence factor and additional proteins that could be useful as potential vaccine targets.

scholarly journals Impact of the MIC of Piperacillin-Tazobactam on the Outcome of Patients with Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Escherichia coli

2013 ◽  
Vol 57 (7) ◽  
pp. 3402-3404 ◽  
Author(s):  
Pilar Retamar ◽  
Lorena López-Cerero ◽  
Miguel Angel Muniain ◽  
Álvaro Pascual ◽  
Jesús Rodríguez-Baño ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Bloodstream Infections ◽  
Content Type ◽  
Extended Spectrum ◽  
Tract Infections ◽  
The Impact

ABSTRACTWe investigated the impact of the piperacillin-tazobactam MIC in the outcome of 39 bloodstream infections due to extended-spectrum-β-lactamase-producingEscherichia coli. All 11 patients with urinary tract infections survived, irrespective of the MIC. For other sources, 30-day mortality was lower for isolates with a MIC of ≤2 mg/liter than for isolates with a higher MIC (0% versus 41.1%;P= 0.02).

scholarly journals Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine

2015 ◽  
Vol 83 (7) ◽  
pp. 2605-2613 ◽  
Author(s):  
Jane E. King ◽  
Hasan A. Aal Owaif ◽  
Jia Jia ◽  
Ian S. Roberts
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Urinary Tract ◽  
Epithelial Cells ◽  
Fluorescent Protein ◽  
Phenotypic Diversity ◽  
Epithelial Cell Line ◽  
Upec Strain ◽  
Content Type ◽  
Tract Infections

UropathogenicEscherichia coli(UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomalgfpreporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract.

scholarly journals Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection

mSphere ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Mary P. Leatham-Jensen ◽  
Matthew E. Mokszycki ◽  
David C. Rowley ◽  
Robert Deering ◽  
Jodi L. Camberg ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Metabolic Pathways ◽  
Minimal Medium ◽  
Quiescent State ◽  
Upec Strain ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent UTIs. Here, we report that many UPEC strains enter a quiescent state when ≤106 CFU are seeded on glucose M9 minimal medium agar plates and show that mutations in several genes involved in central carbon metabolism prevent quiescence, as well as persistence, possibly identifying metabolic pathways involved in UPEC quiescence and persistence in vivo. In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤106 CFU. The cells on glucose plates appear to be in a “quiescent” state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent UTIs. Here, we report that many UPEC strains enter a quiescent state when ≤106 CFU are seeded on glucose M9 minimal medium agar plates and show that mutations in several genes involved in central carbon metabolism prevent quiescence, as well as persistence, possibly identifying metabolic pathways involved in UPEC quiescence and persistence in vivo.

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