Molecular Variations in Klebsiella pneumoniae and Escherichia coli FimH Affect Function and Pathogenesis in the Urinary Tract

ABSTRACT Type 1 pili mediate binding, invasion, and biofilm formation of uropathogenic Escherichia coli (UPEC) in the host urothelium during urinary tract infection (UTI) via the adhesin FimH. In this study, we characterized the molecular basis of functional differences between FimH of the UPEC isolate UTI89 and the Klebsiella pneumoniae cystitis isolate TOP52. Type 1 pili characteristically mediate mannose-sensitive hemagglutination of guinea pig erythrocytes. Although the adhesin domain of K. pneumoniae TOP52 FimH (FimH52) is highly homologous to that of E. coli, with an identical mannose binding pocket and surrounding hydrophobic ridge, it lacks the ability to agglutinate guinea pig erythrocytes. In addition, FimH-dependent biofilm formation in K. pneumoniae is inhibited by heptyl mannose, but not methyl mannose, suggesting the need for contacts outside of the mannose binding pocket. The binding specificity differences observed for FimH52 resulted in significant functional differences seen in the pathogenesis of K. pneumoniae UTI compared to E. coli UTI. Infections in a murine model of UTI demonstrated that although the K. pneumoniae strain TOP52 required FimH52 for invasion and IBC formation in the bladder, FimH52 was not essential for early colonization. This work reveals that a limited amount of sequence variation between the FimH of E. coli and K. pneumoniae results in significant differences in function and ability to colonize the urinary tract.

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The UbiI (VisC) Aerobic Ubiquinone Synthase Is Required for Expression of Type 1 Pili, Biofilm Formation, and Pathogenesis in Uropathogenic Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.00030-16 ◽

2016 ◽

Vol 198 (19) ◽

pp. 2662-2672 ◽

Cited By ~ 12

Author(s):

Kyle A. Floyd ◽

Courtney A. Mitchell ◽

Allison R. Eberly ◽

Spencer J. Colling ◽

Ellisa W. Zhang ◽

...

Keyword(s):

Urinary Tract ◽

Biofilm Formation ◽

Energy Deficit ◽

Wild Type ◽

Content Type ◽

Anoxic Conditions ◽

E Coli ◽

Type 1 Pili ◽

Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC), which causes the majority of urinary tract infections (UTI), uses pilus-mediated adherence to initiate biofilm formation in the urinary tract. Oxygen gradients withinE. colibiofilms regulate expression and localization of adhesive type 1 pili. A transposon mutant screen for strains defective in biofilm formation identified theubiI(formerlyvisC) aerobic ubiquinone synthase gene as critical for UPEC biofilm formation. In this study, we characterized a nonpolarubiIdeletion mutant and compared its behavior to that of wild-type bacteria grown under aerobic and anoxic conditions. Consistent with its function as an aerobic ubiquinone-8 synthase, deletion ofubiIin UPEC resulted in reduced membrane potential, diminished motility, and reduced expression of chaperone-usher pathway pili. Loss of aerobic respiration was previously shown to negatively impact expression of type 1 pili. To determine whether this reduction in type 1 pili was due to an energy deficit, wild-type UPEC and theubiImutant were compared for energy-dependent phenotypes under anoxic conditions, in which quinone synthesis is undertaken by anaerobic quinone synthases. Under anoxic conditions, the two strains exhibited wild-type levels of motility but produced diminished numbers of type 1 pili, suggesting that the reduction of type 1 pilus expression in the absence of oxygen is not due to a cellular energy deficit. Acute- and chronic-infection studies in a mouse model of UTI revealed a significant virulence deficit in theubiImutant, indicating that UPEC encounters enough oxygen in the bladder to induce aerobic ubiquinone synthesis during infection.IMPORTANCEThe majority of urinary tract infections are caused by uropathogenicE. coli, a bacterium that can respire in the presence and absence of oxygen. The bladder environment is hypoxic, with oxygen concentrations ranging from 4% to 7%, compared to 21% atmospheric oxygen. This work provides evidence that aerobic ubiquinone synthesis must be engaged during bladder infection, indicating that UPEC bacteria sense and use oxygen as a terminal electron acceptor in the bladder and that this ability drives infection potential despite the fact that UPEC is a facultative anaerobe.

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Immunoglobulin-Mediated Agglutination of and Biofilm Formation by Escherichia coli K-12 Require the Type 1 Pilus Fiber

Infection and Immunity ◽

10.1128/iai.72.4.1929-1938.2004 ◽

2004 ◽

Vol 72 (4) ◽

pp. 1929-1938 ◽

Cited By ~ 32

Author(s):

Paul E. Orndorff ◽

Aditya Devapali ◽

Sarah Palestrant ◽

Aaron Wyse ◽

Mary Lou Everett ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Immunoglobulin A ◽

Minor Component ◽

Secretory Iga ◽

Bacterial Surface ◽

E Coli ◽

Type 1 Pili ◽

K 12

ABSTRACT The binding of human secretory immunoglobulin A (SIgA), the primary immunoglobulin in the gut, to Escherichia coli is thought to be dependent on type 1 pili. Type 1 pili are filamentous bacterial surface attachment organelles comprised principally of a single protein, the product of the fimA gene. A minor component of the pilus fiber (the product of the fimH gene, termed the adhesin) mediates attachment to a variety of host cell molecules in a mannose inhibitable interaction that has been extensively described. We found that the aggregation of E. coli K-12 by human secretory IgA (SIgA) was dependent on the presence of the pilus fiber, even in the absence of the mannose specific adhesin or in the presence of 25 mM α-CH3Man. The presence of pilus without adhesin also facilitated SIgA-mediated biofilm formation on polystyrene, although biofilm formation was stronger in the presence of the adhesin. IgM also mediated aggregation and biofilm formation in a manner dependent on pili with or without adhesin. These findings indicate that the pilus fiber, even in the absence of the adhesin, may play a role in biologically important processes. Under conditions in which E. coli was agglutinated by SIgA, the binding of SIgA to E. coli was not increased by the presence of the pili, with or without adhesin. This observation suggests that the pili, with or without adhesin, affect factors such as cell surface rigidity or electrostatic repulsion, which can affect agglutination but which do not necessarily determine the level of bound immunoglobulin.

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Utilization of an Intracellular Bacterial Community Pathway in Klebsiella pneumoniae Urinary Tract Infection and the Effects of FimK on Type 1 Pilus Expression

Infection and Immunity ◽

10.1128/iai.00090-08 ◽

2008 ◽

Vol 76 (7) ◽

pp. 3337-3345 ◽

Cited By ~ 85

Author(s):

David A. Rosen ◽

Jerome S. Pinkner ◽

Jennifer M. Jones ◽

Jennifer N. Walker ◽

Steven Clegg ◽

...

Keyword(s):

Urinary Tract Infection ◽

Urinary Tract ◽

Tract Infection ◽

Klebsiella Pneumoniae ◽

Biofilm Formation ◽

Phase Variation ◽

Time Points ◽

Type 1 Pili

ABSTRACT Klebsiella pneumoniae is an important cause of urinary tract infection (UTI), but little is known about its pathogenesis in vivo. The pathogenesis of the K. pneumoniae cystitis isolate TOP52 was compared to that of the uropathogenic Escherichia coli (UPEC) isolate UTI89 in a murine cystitis model. Bladder and kidney titers of TOP52 were lower than those of UTI89 at early time points but similar at later time points. TOP52, like UTI89, formed biofilm-like intracellular bacterial communities (IBCs) within the murine bladder, albeit at significantly lower levels than UTI89. Additionally, filamentation of TOP52 was observed, a process critical for UTI89 evasion of neutrophil phagocytosis and persistence in the bladder. Thus, the IBC pathway is not specific to UPEC alone. We investigated if differences in type 1 pilus expression may explain TOP52's early defect in vivo. The type 1 pilus operon is controlled by recombinase-mediated (fimE, fimB, and fimX) phase variation of an invertible promoter element. We found that K. pneumoniae carries an extra gene of unknown function at the 3′ end of its type 1 operon, fimK, and the genome lacks the recombinase fimX. A deletion mutant of fimK was constructed, and TOP52 ΔfimK had higher titers and formed more IBCs in the murine cystitis model than wild type. The loss of fimK or expression of E. coli fimX from a plasmid in TOP52 resulted in a larger phase-ON population and higher expression levels of type 1 pili and gave TOP52 the ability to form type 1-dependent biofilms. Complementation with pfimK decreased type 1 pilus expression and biofilm formation of TOP52 ΔfimK and decreased UTI89 biofilm formation. Thus, K. pneumoniae appears programmed for minimal expression of type 1 pili, which may explain, in part, why K. pneumoniae is a less prevalent etiologic agent of UTI than UPEC.

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Outcome of community-onset ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and urinary tract infection: a population-based cohort study in Denmark

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa361 ◽

2020 ◽

Vol 75 (12) ◽

pp. 3656-3664

Author(s):

Rasmus Richelsen ◽

Jesper Smit ◽

Henrik Carl Schønheyder ◽

Pavithra Laxsen Anru ◽

Belen Gutiérrez-Gutiérrez ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract Infection ◽

Cohort Study ◽

Urinary Tract ◽

Tract Infection ◽

Klebsiella Pneumoniae ◽

Population Based ◽

Esbl Production ◽

E Coli ◽

Community Onset

Abstract Objectives To assess the impact of ESBL production on mortality and length of hospital stay (LOS) of community-onset infections due to Escherichia coli or Klebsiella pneumoniae. Methods A population-based cohort study including all adult patients hospitalized with a first-time community-onset E. coli or K. pneumoniae bacteraemia or urinary tract infection in the North Denmark Region between 2007 and 2017. For each bacterial agent, we computed 1 year Kaplan–Meier survival curves and cumulative incidence functions of LOS, and by use of Cox proportional hazard regression we computed HRs as estimates of 30 day and 1 year mortality rate ratios (MRRs) and LOS among patients with and without ESBL-producing infections. Results We included 24 518 cases (among 22350 unique patients), of whom 1018 (4.2%) were infected by an ESBL-producing bacterium. The 30 day cumulative mortality and adjusted MRR (aMRR) in patients with and without ESBL-producing isolates was as follows: E. coli bacteraemia (n = 3831), 15.8% versus 14.0%, aMRR = 1.01 (95% CI = 0.70–1.45); E. coli urinary tract infection (n = 17151), 9.5% versus 8.7%, aMRR = 0.97 (95% CI = 0.75–1.26); K. pneumoniae bacteraemia (n = 734), 0% versus 17.2%, aMRR = not applicable; and K. pneumoniae urinary tract infection (n = 2802), 13.8% versus 10.7%, aMRR = 1.13 (95% CI = 0.73–1.75). The 1 year aMRR remained roughly unchanged. ESBL-producing E. coli bacteraemia was associated with an increased LOS compared with non-ESBL production. Conclusions ESBL production was not associated with an increased short- or long-term mortality in community-onset infections due to E. coli or K. pneumoniae, yet ESBL-producing E. coli bacteraemia was associated with an increased LOS.

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Uropathogenic Escherichia coli Triggers Oxygen-Dependent Apoptosis in Human Neutrophils through the Cooperative Effect of Type 1 Fimbriae and Lipopolysaccharide

Infection and Immunity ◽

10.1128/iai.72.8.4570-4578.2004 ◽

2004 ◽

Vol 72 (8) ◽

pp. 4570-4578 ◽

Cited By ~ 39

Author(s):

Robert Blomgran ◽

Limin Zheng ◽

Olle Stendahl

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Human Neutrophils ◽

Dependent Manner ◽

E Coli ◽

Type 1 Fimbriae ◽

The Difference ◽

Tract Infections ◽

Neutrophil Survival

ABSTRACT Type 1 fimbriae are the most commonly expressed virulence factor on uropathogenic Escherichia coli. In addition to promoting avid bacterial adherence to the uroepithelium and enabling colonization, type 1 fimbriae recruit neutrophils to the urinary tract as an early inflammatory response. Using clinical isolates of type 1 fimbriated E. coli and an isogenic type 1 fimbria-negative mutant (CN1016) lacking the FimH adhesin, we investigated if these strains could modulate apoptosis in human neutrophils. We found that E. coli expressing type 1 fimbriae interacted with neutrophils in a mannose- and lipopolysaccharide (LPS)-dependent manner, leading to apoptosis which was triggered by the intracellular generation of reactive oxygen species. This induced neutrophil apoptosis was abolished by blocking FimH-mediated attachment, by inhibiting NADPH oxidase activation, or by neutralizing LPS. In contrast, CN1016, which did not adhere to or activate the respiratory burst of neutrophils, delayed the spontaneous apoptosis in an LPS-dependent manner. This delayed apoptosis could be mimicked by adding purified LPS and was also observed by using fimbriated bacteria in the presence of d-mannose. These results suggest that LPS is required for E. coli to exert both pro- and antiapoptotic effects on neutrophils and that the difference in LPS presentation (i.e., with or without fimbriae) determines the outcome. The present study showed that there is a fine-tuned balance between type 1 fimbria-induced and LPS-mediated delay of apoptosis in human neutrophils, in which altered fimbrial expression on uropathogenic E. coli determines the neutrophil survival and the subsequent inflammation during urinary tract infections.

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Periplasmic Peptidyl Prolyl cis-trans Isomerases Are Not Essential for Viability, but SurA Is Required for Pilus Biogenesis in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.187.22.7680-7686.2005 ◽

2005 ◽

Vol 187 (22) ◽

pp. 7680-7686 ◽

Cited By ~ 98

Author(s):

Sheryl S. Justice ◽

David A. Hunstad ◽

Jill Reiss Harper ◽

Amy R. Duguay ◽

Jerome S. Pinkner ◽

...

Keyword(s):

Escherichia Coli ◽

Outer Membrane Proteins ◽

E Coli ◽

Outer Membranes ◽

Type 1 Pili ◽

Pilus Biogenesis ◽

Quadruple Mutant ◽

Increased Susceptibility ◽

Pilus Assembly

ABSTRACT In Escherichia coli, FkpA, PpiA, PpiD, and SurA are the four known periplasmic cis-trans prolyl isomerases. These isomerases facilitate proper protein folding by increasing the rate of transition of proline residues between the cis and trans states. Genetic inactivation of all four periplasmic isomerases resulted in a viable strain that exhibited a decreased growth rate and increased susceptibility to certain antibiotics. Levels of the outer membrane proteins LamB and OmpA in the quadruple mutant were indistinguishable from those in the surA single mutant. In addition, expression of P and type 1 pili (adhesive organelles produced by uropathogenic strains of E. coli and assembled by the chaperone/usher pathway) were severely diminished in the absence of the four periplasmic isomerases. Maturation of the usher was significantly impaired in the outer membranes of strains devoid of all four periplasmic isomerases, resulting in a defect in pilus assembly. Moreover, this defect in pilus assembly and usher stability could be attributed to the absence of SurA. The data presented here suggest that the four periplasmic isomerases are not essential for growth under laboratory conditions but may have significant roles in survival in environmental and pathogenic niches, as indicated by the effect on pilus production.

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Multiple-Antibiotic Resistance Mediated by Plasmids and Integrons in Uropathogenic Escherichia coli and Klebsiella pneumoniae

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v24i1.1231 ◽

1970 ◽

Vol 24 (1) ◽

pp. 19-23 ◽

Cited By ~ 7

Author(s):

Taslima Taher Lina ◽

Sabita Rezwana Rahman ◽

Donald James Gomes

Keyword(s):

Escherichia Coli ◽

Drug Resistance ◽

Urinary Tract Infection ◽

Antibiotic Resistance ◽

Urinary Tract ◽

Tract Infection ◽

Klebsiella Pneumoniae ◽

High Rate ◽

E Coli ◽

Class 1

Antibiotic resistance in urinary tract infection (UTI) is a growing public health problem in the world. In this study, a total of 182 uropathogens were isolated from patients with symptoms of urinary tract infection (UTI). Escherichia coli (88%) was the most prevalent isolate, while Klebsiella pneumoniae was recovered from 12% cases. The male/female ratio was 1:3. About 56% female and 51% male patients belonged to the age group >40 years. The antibiotic resistance rates of the isolates to fifteen different drugs were investigated. E. coli and K. pneumoniae showed variable pattern of susceptibility. The percentage of resistance to different drugs was higher in E. coli isolates compared to that of K. pneumoniae. Among the total number of isolates about 87% were resistant to at least three commonly used antibiotics. All the isolates were sensitive to imipenem. Analysis of the plasmid DNA had shown that the plasmid pattern was very diverse in both E. coli and K. pneumoniae. All the isolates contained multiple numbers of plasmid ranging from 1.0 to >140 MDa. Middleranged plasmids (30 to 80 MDa), the transferable resistance plasmids, were found to be present in 86% E. coli and 85% K. pneumoniae isolates. The strong association observed between plasmid profiles and drug resistance patterns suggest that plasmids other than the common plasmids may have epidemiological significance. The presence of class 1 and class 2 integrons were also investigated. A relatively high occurrence of class 1 integrons, that are associated with lateral transfer of antibacterial resistance genes, was observed in K. pneumoniae (88%) than in E. coli isolates (54%). Class 2 integrons were not found in any of the E. coli and K. pneumoniae isolates. These results show the high rate of drug resistance and the presence of high rate of transferable elements in these MDR isolates. Keywords: Uropathogens, Escherichia coli, Klebsiella pneumoniae, Multidrug-resistant (MDR) bacteria, Plasmid profiles, IntegronsDOI: http://dx.doi.org/10.3329/bjm.v24i1.1231 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 19-23

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Abolition of Biofilm Formation in Urinary Tract Escherichia coli and Klebsiella Isolates by Metal Interference through Competition for Fur

Applied and Environmental Microbiology ◽

10.1128/aem.00241-10 ◽

2010 ◽

Vol 76 (12) ◽

pp. 3836-3841 ◽

Cited By ~ 38

Author(s):

Viktoria Hancock ◽

Malin Dahl ◽

Per Klemm

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Biofilm Formation ◽

Iron Uptake ◽

Regulatory System ◽

Bacterial Biofilms ◽

Divalent Metal Ions ◽

Chronic Infections ◽

E Coli ◽

Microtiter Plates

ABSTRACT Bacterial biofilms are associated with a large number of persistent and chronic infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics and immune defenses, which makes it hard if not impossible to eradicate biofilm-associated infections. In the urinary tract, free iron is strictly limited but is critical for bacterial growth. Biofilm-associated Escherichia coli cells are particularly desperate for iron. An attractive way of inhibiting biofilm formation is to fool the bacterial regulatory system for iron uptake. Here, we demonstrate that biofilm formation can be impaired by the addition of divalent metal ions, such as Zn(II) and Co(II), which inhibit iron uptake by virtue of their higher-than-iron affinity for the master controller protein of iron uptake, Fur. Reduced biofilm formation of urinary tract-infectious E. coli strains in the presence of Zn(II) was observed in microtiter plates and flow chambers as well as on urinary catheters. These results further support that iron uptake is indeed crucial for biofilm formation, and thereby, targeting these uptake systems might be an effective way to eradicate biofilms caused by infectious strains.

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