scholarly journals UreR, the Transcriptional Activator of the Proteus mirabilis Urease Gene Cluster, Is Required for Urease Activity and Virulence in Experimental Urinary Tract Infections

2003 ◽  
Vol 71 (2) ◽  
pp. 1026-1030 ◽  
Author(s):  
Jonathan D. Dattelbaum ◽  
C. Virginia Lockatell ◽  
David E. Johnson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Gene Cluster ◽  
Proteus Mirabilis ◽  
Urease Activity ◽  
Complicated Urinary Tract Infection ◽  
Wild Type ◽  
Urease Gene ◽  
Low Copy Number ◽  
Mutant Strains ◽  
Tract Infections

ABSTRACT Proteus mirabilis, a cause of complicated urinary tract infection, produces urease, an essential virulence factor for this species. UreR, a member of the AraC/XylS family of transcriptional regulators, positively activates expression of the ure gene cluster in the presence of urea. To specifically evaluate the contribution of UreR to urease activity and virulence in the urinary tract, a ureR mutation was introduced into P. mirabilis HI4320 by homologous recombination. The isogenic ureR::aphA mutant, deficient in UreR production, lacked measurable urease activity. Expression was not detected in the UreR-deficient strain by Western blotting with monoclonal antibodies raised against UreD. Urease activity and UreD expression were restored by complementation of the mutant strain with ureR expressed from a low-copy-number plasmid. Virulence was assessed by transurethral cochallenge of CBA mice with wild-type and mutant strains. The isogenic ureR::aphA mutant of HI4320 was outcompeted in the urine (P = 0.004), bladder (P = 0.016), and kidneys (P ≤ 0.001) 7 days after inoculation. Thus, UreR is required for basal urease activity in the absence of urea, for induction of urease by urea, and for virulence of P. mirabilis in the urinary tract.

scholarly journals Mannose-Resistant Proteus-Like Fimbriae Are Produced by Most Proteus mirabilis Strains Infecting the Urinary Tract, Dictate the In Vivo Localization of Bacteria, and Contribute to Biofilm Formation

2004 ◽  
Vol 72 (12) ◽  
pp. 7294-7305 ◽  
Author(s):  
Angela M. Jansen ◽  
Virginia Lockatell ◽  
David E. Johnson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Proteus Mirabilis ◽  
Biofilm Formation ◽  
Constitutive Expression ◽  
Etiologic Agent ◽  
Phase Variable ◽  
Wild Type ◽  
Bladder Tissue ◽  
Tract Infections

ABSTRACT Proteus mirabilis, an etiologic agent of complicated urinary tract infections, expresses mannose-resistant Proteus-like (MR/P) fimbriae whose expression is phase variable. Here we examine the role of these fimbriae in biofilm formation and colonization of the urinary tract. The majority of wild-type P. mirabilis cells in transurethrally infected mice produced MR/P fimbriae. Mutants that were phase-locked for either constitutive expression (MR/P ON) or the inability to express MR/P fimbriae (MR/P OFF) were phenotypically distinct and swarmed at different rates. The number of P. mirabilis cells adhering to bladder tissue did not appear to be affected by MR/P fimbriation. However, the pattern of adherence to the bladder surface was strikingly different. MR/P OFF colonized the lamina propria underlying exfoliated uroepithelium, while MR/P ON colonized the luminal surfaces of bladder umbrella cells and not the exfoliated regions. Wild-type P. mirabilis was usually found colonizing intact uroepithelium, but it occasionally adhered to exfoliated areas. MR/P ON formed significantly more biofilm than either P. mirabilis HI4320 (P = 0.03) or MR/P OFF (P = 0.05). MR/P OFF was able to form a biofilm similar to that of the wild type. MR/P ON formed a three-dimensional biofilm structure as early as 18 h after the initiation of the biofilm, while MR/P OFF and the wild type did not. After 7 days, however, P. mirabilis HI4320 formed a 65-μm-thick biofilm, while the thickest MR/P ON and MR/P OFF biofilms were only 12 μm thick. We concluded that MR/P fimbriae are expressed by most P. mirabilis cells infecting the urinary tract, dictate the localization of bacteria in the bladder, and contribute to biofilm formation.

scholarly journals H-NS Is a Repressor of the Proteus mirabilis Urease Transcriptional Activator GeneureR

2000 ◽  
Vol 182 (9) ◽  
pp. 2649-2653 ◽  
Author(s):  
Christopher Coker ◽  
Olubunmi O. Bakare ◽  
Harry L. T. Mobley
Keyword(s):  
Nucleotide Sequence ◽  
Proteus Mirabilis ◽  
Binding Sites ◽  
Recombinant Plasmid ◽  
Urease Activity ◽  
Transcriptional Activator ◽  
Galactosidase Activity ◽  
Wild Type ◽  
Urease Gene ◽  
In Trans

ABSTRACT Expression of Proteus mirabilis urease is governed by UreR, an AraC-like positive transcriptional activator. A poly(A) tract nucleotide sequence, consisting of A6TA2CA2TGGTA5GA6TGA5, is located 16 bp upstream of the ς70-likeureR promoter P2. Since poly(A) tracts of DNA serve as binding sites for the gene repressor histone-like nucleoid structuring protein (H-NS), we measured β-galactosidase activity of wild-typeEscherichia coli MC4100 (H-NS+) and its isogenic derivative ATM121 (hns::Tn10) (H-NS−) harboring a ureR-lacZ operon fusion plasmid (pLC9801). β-Galactosidase activity in the H-NS− host strain was constitutive and sevenfold greater (P < 0.0001) than that in the H-NS+ host. A recombinant plasmid containing cloned P. mirabilis hns was able to complement and restore repression of the ureR promoter in the H-NS−host when provided in trans. Deletion of the poly(A) tract nucleotide sequence from pLC9801 resulted in an increase in β-galactosidase activity in the H-NS+ host to nearly the same levels as that observed for wild-type pLC9801 harbored by the H-NS−host. Urease activity in strains harboring the recombinant plasmid pMID1010 (encoding the entire urease gene cluster of P. mirabilis) was equivalent in both the H-NS−background and the H-NS+ background in the presence of urea but was eightfold greater (P = 0.0001) in the H-NS− background in the absence of urea. We conclude that H-NS represses ureR expression in the absence of urea induction.

scholarly journals The type III secretion system of Proteus mirabilis HI4320 does not contribute to virulence in the mouse model of ascending urinary tract infection

2007 ◽  
Vol 56 (10) ◽  
pp. 1277-1283 ◽  
Author(s):  
Melanie M. Pearson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Mouse Model ◽  
Proteus Mirabilis ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Negative Regulator ◽  
Wild Type ◽  
Type Iii ◽  
Tract Infections

The Gram-negative enteric bacterium Proteus mirabilis is a frequent cause of urinary tract infections (UTIs) in individuals with long-term indwelling catheters or with complicated urinary tracts. The recent release of the P. mirabilis strain HI4320 genome sequence has facilitated identification of potential virulence factors in this organism. Genes appearing to encode a type III secretion system (TTSS) were found in a low GC-content pathogenicity island in the P. mirabilis chromosome. This island contains 24 intact genes that appear to encode all components necessary to assemble a TTSS needle complex, plus at least two putative secreted effector proteins and their chaperones. The genetic organization of the TTSS genes is very similar to that of the TTSS of Shigella flexneri. RT-PCR analysis indicated that these genes are expressed at low levels in vitro. However, insertional mutation of two putative TTSS genes, encoding the requisite ATPase and a possible negative regulator, resulted in no change in either the growth rate of the mutant or the secreted protein profile compared to wild-type. Furthermore, there was no difference in quantitative cultures of urine, bladder and kidney between the ATPase mutant and the wild-type strain in the mouse model of ascending UTI in either independent challenge or co-challenge experiments. The role of the P. mirabilis TTSS, if any, is yet to be determined.

scholarly journals Ureolytic Biomineralization Reduces Proteus mirabilis Biofilm Susceptibility to Ciprofloxacin

2016 ◽  
Vol 60 (5) ◽  
pp. 2993-3000 ◽  
Author(s):  
Xiaobao Li ◽  
Nanxi Lu ◽  
Hannah R. Brady ◽  
Aaron I. Packman
Keyword(s):  
Urinary Tract ◽  
Proteus Mirabilis ◽  
Growth Conditions ◽  
Wild Type ◽  
Content Type ◽  
Microbial Biofilms ◽  
Viable Cells ◽  
Urinary Tract Calculi ◽  
Artificial Urine ◽  
Tract Infections

ABSTRACTUreolytic biomineralization induced by urease-producing bacteria, particularlyProteus mirabilis, is responsible for the formation of urinary tract calculi and the encrustation of indwelling urinary catheters. Such microbial biofilms are challenging to eradicate and contribute to the persistence of catheter-associated urinary tract infections, but the mechanisms responsible for this recalcitrance remain obscure. In this study, we characterized the susceptibility of wild-type (ure+) and urease-negative (ure−)P. mirabilisbiofilms to killing by ciprofloxacin. Ure+ biofilms produced fine biomineral precipitates that were homogeneously distributed within the biofilm biomass in artificial urine, while ure− biofilms did not produce biomineral deposits under identical growth conditions. Following exposure to ciprofloxacin, ure+ biofilms showed greater survival (less killing) than ure− biofilms, indicating that biomineralization protected biofilm-resident cells against the antimicrobial. To evaluate the mechanism responsible for this recalcitrance, we observed and quantified the transport of Cy5-conjugated ciprofloxacin into the biofilm by video confocal microscopy. These observations revealed that the reduced susceptibility of ure+ biofilms resulted from hindered delivery of ciprofloxacin into biomineralized regions of the biofilm. Further, biomineralization enhanced retention of viable cells on the surface following antimicrobial exposure. These findings together show that ureolytic biomineralization induced byP. mirabilismetabolism strongly regulates antimicrobial susceptibility by reducing internal solute transport and increasing biofilm stability.

scholarly journals Zinc Uptake Contributes to Motility and Provides a Competitive Advantage to Proteus mirabilis during Experimental Urinary Tract Infection

2010 ◽  
Vol 78 (6) ◽  
pp. 2823-2833 ◽  
Author(s):  
Greta R. Nielubowicz ◽  
Sara N. Smith ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Proteus Mirabilis ◽  
Minimal Medium ◽  
Zinc Transport ◽  
Negative Bacterium ◽  
Wild Type ◽  
Membrane Component ◽  
Swarming Motility ◽  
High Affinity ◽  
Tract Infections

ABSTRACTProteus mirabilis, a Gram-negative bacterium, represents a common cause of complicated urinary tract infections in catheterized patients or those with functional or anatomical abnormalities of the urinary tract. ZnuB, the membrane component of the high-affinity zinc (Zn2+) transport system ZnuACB, was previously shown to be recognized by sera from infected mice. Since this system has been shown to contribute to virulence in other pathogens, its role inProteus mirabiliswas investigated by constructing a strain with an insertionally interrupted copy ofznuC. TheznuC::Kan mutant was more sensitive to zinc limitation than the wild type, was outcompeted by the wild type in minimal medium, displayed reduced swimming and swarming motility, and produced lessflaAtranscript and flagellin protein. The production of flagellin and swarming motility were restored by complementation withznuCBintrans. Swarming motility was also restored by the addition of Zn2+to the agar prior to inoculation; the addition of Fe2+to the agar also partially restored the swarming motility of theznuC::Kan strain, but the addition of Co2+, Cu2+, or Ni2+did not. ZnuC contributes to but is not required for virulence in the urinary tract; theznuC::Kan strain was outcompeted by the wild type during a cochallenge experiment but was able to colonize mice to levels similar to the wild-type level during independent challenge. Since we demonstrated a role for ZnuC in zinc transport, we hypothesize that there is limited zinc present in the urinary tract andP. mirabilismust scavenge this ion to colonize and persist in the host.

scholarly journals 1675. Epidemiology of Urinary Tract Infections in the United States, 2009 - 2018

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S823-S823
Author(s):  
Kendra Foster ◽  
Linnea A Polgreen ◽  
Brett Faine ◽  
Philip M Polgreen
Keyword(s):  
United States ◽  
Urinary Tract ◽  
Klebsiella Pneumoniae ◽  
Urinary Tract Infections ◽  
Proteus Mirabilis ◽  
Antibiotic Use ◽  
The United States ◽  
Drug Resistant ◽  
E Coli ◽  
Tract Infections

Abstract Background Urinary tract infections (UTIs) are one of the most common bacterial infections. There is a lack of large epidemiologic studies evaluating the etiologies of UTIs in the United States. This study aimed to determine the prevalence of different UTI-causing organisms and their antimicrobial susceptibility profiles among patients being treated in a hospital setting. Methods We used the Premier Healthcare Database. Patients with a primary diagnosis code of cystitis, pyelonephritis, or urinary tract infection and had a urine culture from 2009- 2018 were included in the study. Both inpatients and patients who were only treated in the emergency department (ED) were included. We calculated descriptive statistics for uropathogens and their susceptibilities. Multi-drug-resistant pathogens are defined as pathogens resistant to 3 or more antibiotics. Resistance patterns are also described for specific drug classes, like resistance to fluoroquinolones. We also evaluated antibiotic use in this patient population and how antibiotic use varied during the hospitalization. Results There were 640,285 individuals who met the inclusion criteria. Females make up 82% of the study population and 45% were age 65 or older. The most common uropathogen was Escherichia Coli (64.9%) followed by Klebsiella pneumoniae (8.3%), and Proteus mirabilis (5.7%). 22.2% of patients were infected with a multi-drug-resistant pathogen. We found that E. Coli was multi-drug resistant 23.8% of the time; Klebsiella pneumoniae was multi-drug resistant 7.4%; and Proteus mirabilis was multi-drug resistant 2.8%. The most common antibiotics prescribed were ceftriaxone, levofloxacin, and ciprofloxacin. Among patients that were prescribed ceftriaxone, 31.7% of them switched to a different antibiotic during their hospitalization. Patients that were prescribed levofloxacin and ciprofloxacin switched to a different antibiotic 42.8% and 41.5% of the time, respectively. Conclusion E. Coli showed significant multidrug resistance in this population of UTI patients that were hospitalized or treated within the ED, and antibiotic switching is common. Disclosures All Authors: No reported disclosures

Urinary Tract Infections Caused by Multi-Drug Resistant Proteus mirabilis: Risk Factors and Clinical Outcomes

Infection ◽  
2009 ◽  
Vol 38 (1) ◽  
pp. 41-46 ◽  
Author(s):  
K. Cohen-Nahum ◽  
L. Saidel-Odes ◽  
K. Riesenberg ◽  
F. Schlaeffer ◽  
A. Borer
Keyword(s):  
Risk Factors ◽  
Urinary Tract ◽  
Clinical Outcomes ◽  
Urinary Tract Infections ◽  
Proteus Mirabilis ◽  
Drug Resistant ◽  
Tract Infections

scholarly journals New Aspects of RpoE in Uropathogenic Proteus mirabilis

2014 ◽  
Vol 83 (3) ◽  
pp. 966-977 ◽  
Author(s):  
Ming-Che Liu ◽  
Kuan-Ting Kuo ◽  
Hsiung-Fei Chien ◽  
Yi-Lin Tsai ◽  
Shwu-Jen Liaw
Keyword(s):  
Urinary Tract ◽  
Virulence Factors ◽  
Stress Responses ◽  
Proteus Mirabilis ◽  
Immune Cell ◽  
Polymyxin B ◽  
Urothelial Cells ◽  
Cationic Antimicrobial Peptide ◽  
Content Type ◽  
Tract Infections

Proteus mirabilisis a common human pathogen causing recurrent or persistent urinary tract infections (UTIs). The underlying mechanisms forP. mirabilisto establish UTIs are not fully elucidated. In this study, we showed that loss of the sigma factor E (RpoE), mediating extracytoplasmic stress responses, decreased fimbria expression, survival in macrophages, cell invasion, and colonization in mice but increased the interleukin-8 (IL-8) expression of urothelial cells and swarming motility. This is the first study to demonstrate that RpoE modulated expression of MR/P fimbriae by regulatingmrpI, a gene encoding a recombinase controlling the orientation of MR/P fimbria promoter. By real-time reverse transcription-PCR, we found that the IL-8 mRNA amount of urothelial cells was induced significantly by lipopolysaccharides extracted fromrpoEmutant but not from the wild type. These RpoE-associated virulence factors should be coordinately expressed to enhance the fitness ofP. mirabilisin the host, including the avoidance of immune attacks. Accordingly,rpoEmutant-infected mice displayed more immune cell infiltration in bladders and kidneys during early stages of infection, and therpoEmutant had a dramatically impaired ability of colonization. Moreover, it is noteworthy that urea (the major component in urine) and polymyxin B (a cationic antimicrobial peptide) can induce expression ofrpoEby the reporter assay, suggesting that RpoE might be activated in the urinary tract. Altogether, our results indicate that RpoE is important in sensing environmental cues of the urinary tract and subsequently triggering the expression of virulence factors, which are associated with the fitness ofP. mirabilis, to build up a UTI.

scholarly journals The Extracellular Domain of the β2Integrin β Subunit (CD18) Is Sufficient forEscherichia coliHemolysin andAggregatibacter actinomycetemcomitansLeukotoxin Cytotoxic Activity

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Laura C. Ristow ◽  
Vy Tran ◽  
Kevin J. Schwartz ◽  
Lillie Pankratz ◽  
Andrew Mehle ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Integrin Signaling ◽  
Β Subunit ◽  
Wild Type ◽  
Α Subunit ◽  
Content Type ◽  
Animal Pathogens ◽  
Tract Infections

ABSTRACTTheEscherichia colihemolysin (HlyA) is a pore-forming exotoxin associated with severe complications of human urinary tract infections. HlyA is the prototype of the repeats-in-toxin (RTX) family, which includes LtxA fromAggregatibacter actinomycetemcomitans, a periodontal pathogen. The existence and requirement for a host cell receptor for these toxins are controversial. We performed an unbiased forward genetic selection in a mutant library of human monocytic cells, U-937, for host factors involved in HlyA cytotoxicity. The top candidate was the β2integrin β subunit. Δβ2cell lines are approximately 100-fold more resistant than wild-type U-937 cells to HlyA, but remain sensitive to HlyA at high concentrations. Similarly, Δβ2cells are more resistant than wild-type U-937 cells to LtxA, as Δβ2cells remain LtxA resistant even at >1,000-fold-higher concentrations of the toxin. Loss of any single β2integrin α subunit, or even all four α subunits together, does not confer resistance to HlyA. HlyA and LtxA bind to the β2subunit, but not to αL, αM, or αXin far-Western blots. Genetic complementation of Δβ2cells with either β2or β2with a cytoplasmic tail deletion restores HlyA and LtxA sensitivity, suggesting that β2integrin signaling is not required for cytotoxicity. Finally, β2mutations do not alter sensitivity to unrelated pore-forming toxins, as wild-type or Δβ2cells are equally sensitive toStaphylococcus aureusα-toxin andProteus mirabilisHpmA. Our studies show two RTX toxins use the β2integrin β subunit alone to facilitate cytotoxicity, but downstream integrin signaling is dispensable.IMPORTANCEUrinary tract infections are one of the most common bacterial infections worldwide. UropathogenicEscherichia colistrains are responsible for more than 80% of community-acquired urinary tract infections. Although we have known for nearly a century that severe infections stemming from urinary tract infections, including kidney or bloodstream infections are associated with expression of a toxin, hemolysin, from uropathogenicEscherichia coli, how hemolysin functions to enhance virulence is unknown. Our research defines the interaction of hemolysin with the β2integrin, a human white cell adhesion molecule, as a potential therapeutic target during urinary tract infections. TheE. colihemolysin is the prototype for a toxin family (RTX family) produced by a wide array of human and animal pathogens. Our work extends to the identification and characterization of the receptor for an additional member of the RTX family, suggesting that this interaction may be broadly conserved throughout the RTX toxin family.

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