scholarly journals The RyfA small RNA regulates oxidative and osmotic stress responses and virulence in uropathogenic Escherichia coli

2021 ◽  
Vol 17 (5) ◽  
pp. e1009617
Author(s):  
Hicham Bessaiah ◽  
Pravil Pokharel ◽  
Hamza Loucif ◽  
Merve Kulbay ◽  
Charles Sasseville ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Small Rna ◽  
Stress Responses ◽  
Surface Proteins ◽  
Upec Strain ◽  
Expression Of Genes ◽  
Bacterial Infectious Disease ◽  
Strain Cft073 ◽  
Tract Infections

Urinary tract infections (UTIs) are a common bacterial infectious disease in humans, and strains of uropathogenic Escherichia coli (UPEC) are the most frequent cause of UTIs. During infection, UPEC must cope with a variety of stressful conditions in the urinary tract. Here, we demonstrate that the small RNA (sRNA) RyfA of UPEC strains is required for resistance to oxidative and osmotic stresses. Transcriptomic analysis of the ryfA mutant showed changes in expression of genes associated with general stress responses, metabolism, biofilm formation and genes coding for cell surface proteins. Inactivation of ryfA in UPEC strain CFT073 decreased urinary tract colonization in mice and the ryfA mutant also had reduced production of type 1 and P fimbriae (pili), adhesins which are known to be important for UTI. Furthermore, loss of ryfA also reduced UPEC survival in human macrophages. Thus, ryfA plays a key regulatory role in UPEC adaptation to stress, which contributes to UTI and survival in macrophages.

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 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 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 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 FIMBRIAE AND FLAGELLA MEDIATED SURFACE MOTILITY AND THE EFFECT OF GLUCOSE ON NONPATHOGENIC AND UROPATHOGENIC ESCHERICHIA COLI

2019 ◽  
Author(s):  
Sankalya Ambagaspitiye ◽  
Sushmita Sudarshan ◽  
Jacob Hogins ◽  
Parker McDill ◽  
Nicole J. De Nisco ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Promoter Region ◽  
Upec Strain ◽  
Surface Movement ◽  
E Coli ◽  
Surface Motility ◽  
The Difference ◽  
Tract Infections

ABSTRACTWe characterized the surface motility of nonpathogenic and pathogenic E. coli strains with respect to the appendage requirement, flagella versus fimbriae, and the glucose requirement. Nonpathogenic lab strains exhibited either slow or fast surface movement. The slow strains required type 1 fimbriae for movement, while the fast strains required flagella and had an insertion in the flhDC promoter region. Surface movement of three uropathogenic E. coli (UPEC) strains was fast and required flagella, but these strains did not have an insertion in the flhDC promoter region. We assessed swimming motility as an indicator of flagella synthesis and found that glucose inhibited swimming of the slow nonpathogenic strains but not of the fast nonpathogenic or pathogenic strains. Fimbriae-based surface motility requires glucose, which inhibits cyclic-AMP (cAMP) and flagella synthesis; therefore, we examined whether surface motility required cAMP. The surface motility of a slow, fimbriae-dominant, nonpathogenic strain did not require cAMP, which was expected because fimbriae synthesis does not require cAMP. In contrast, the surface motility of a faster, flagella-dominant, UPEC strain required cAMP, which was unexpected because swarming was unaffected by the presence of glucose. Electron microscopy verified the presence or absence of fimbriae or flagella. In summary, surface motilities of the nonpathogenic and uropathogenic E. coli strains of this study differed in the appendage used and the effects of glucose on flagella synthesis.IMPORTANCEUropathogenic Escherichia coli strains cause 80-90% of community-acquired urinary tract infections, and recurrent urinary tract infections, which can last for years, and often become antibiotic resistant. Urinary tract infections can be associated with intra-vesical lesions extending from localized trigonitis/cystitis to widely distributed pancystitis: motility may be a factor that distinguishes between these infection patterns. Nonpathogenic and uropathogenic E. coli were shown to exhibit fimbriae- and flagella-dependent surface motility, respectively, and the difference was attributed to altered control of flagella synthesis by glucose. Uropathogenic E. coli strains grow more rapidly in urine than nonpathogenic strains, which implies differences in metabolism. Understanding the basis for glucose-insensitive control of flagella-dependent motility could provide insight into uropathogenic E. coli metabolism and virulence.

scholarly journals The IrgA Homologue Adhesin Iha Is an Escherichia coli Virulence Factor in Murine Urinary Tract Infection

2005 ◽  
Vol 73 (2) ◽  
pp. 965-971 ◽  
Author(s):  
James R. Johnson ◽  
Srdjan Jelacic ◽  
Laura M. Schoening ◽  
Connie Clabots ◽  
Nurmohammad Shaikh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factor ◽  
Deletion Mutants ◽  
E Coli ◽  
Uroepithelial Cells ◽  
Strain Cft073 ◽  
Tract Infections ◽  
Gene Homologue

ABSTRACT The role of the Escherichia coli iron-regulated gene homologue adhesin (Iha) in the pathogenesis of urinary tract infections (UTIs) is unknown. We performed a series of complementary analyses to confirm or refute the hypothesis that Iha is a virulence factor in uropathogenic E. coli. Fecal E. coli isolates exhibited significantly lower prevalences of iha (range, 14 to 22%) than did clinical isolates from cases of pediatric cystitis or pyelonephritis, adult pyelonephritis or urosepsis, or bacteremia (range, 38 to 74%). Recombinant Iha from E. coli pyelonephritis isolate CFT073 conferred upon nonadherent E. coli ORN172 the ability to adhere to cultured T-24 human uroepithelial cells. In a well-established mouse model of ascending UTI, CFT073 and its derivative UPEC76 (a pap [P fimbriae] mutant version of strain CFT073) each significantly outcompeted their respective iha deletion mutants in CBA/J mice 48 h after bladder challenge (P < 0.03 for urine, both kidneys, and bladders of both constructs, except for bladders of mice challenged with UPEC76 and its deletion mutant, where P = 0.11). These data suggest that IhaCFT073 is a virulence factor and might be a target for anti-UTI interventions.

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 Defining Genomic Islands and Uropathogen-Specific Genes in Uropathogenic Escherichia coli

2007 ◽  
Vol 189 (9) ◽  
pp. 3532-3546 ◽  
Author(s):  
Amanda L. Lloyd ◽  
David A. Rasko ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Iron Acquisition ◽  
Genomic Islands ◽  
Comparative Genomic ◽  
Upec Strain ◽  
E Coli ◽  
Strain Collection ◽  
Tract Infections ◽  
K 12

ABSTRACT Uropathogenic Escherichia coli (UPEC) strains are responsible for the majority of uncomplicated urinary tract infections, which can present clinically as cystitis or pyelonephritis. UPEC strain CFT073, isolated from the blood of a patient with acute pyelonephritis, was most cytotoxic and most virulent in mice among our strain collection. Based on the genome sequence of CFT073, microarrays were utilized in comparative genomic hybridization (CGH) analysis of a panel of uropathogenic and fecal/commensal E. coli isolates. Genomic DNA from seven UPEC (three pyelonephritis and four cystitis) isolates and three fecal/commensal strains, including K-12 MG1655, was hybridized to the CFT073 microarray. The CFT073 genome contains 5,379 genes; CGH analysis revealed that 2,820 (52.4%) of these genes were common to all 11 E. coli strains, yet only 173 UPEC-specific genes were found by CGH to be present in all UPEC strains but in none of the fecal/commensal strains. When the sequences of three additional sequenced UPEC strains (UTI89, 536, and F11) and a commensal strain (HS) were added to the analysis, 131 genes present in all UPEC strains but in no fecal/commensal strains were identified. Seven previously unrecognized genomic islands (>30 kb) were delineated by CGH in addition to the three known pathogenicity islands. These genomic islands comprise 672 kb of the 5,231-kb (12.8%) genome, demonstrating the importance of horizontal transfer for UPEC and the mosaic structure of the genome. UPEC strains contain a greater number of iron acquisition systems than do fecal/commensal strains, which is reflective of the adaptation to the iron-limiting urinary tract environment. Each strain displayed distinct differences in the number and type of known virulence factors. The large number of hypothetical genes in the CFT073 genome, especially those shown to be UPEC specific, strongly suggests that many urovirulence factors remain uncharacterized.

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