Modelling biofilm-associated urinary tract infections in animals

McLean, Robert; Downey, Joe; Lablans, Ann; Clark, Janet; Dumanski, A J; Nickel, J. Curtis

doi:10.1016/0964-8305(92)90064-u

Cited by 4 publications

(3 citation statements)

References 80 publications

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“…Second, aggregates and multiple layers of bacteria appeared to be embedded in biofilm (polysaccharide matrix) that was loosely attached to surface of the bladder epithelium. Interestingly, bacteria clustered inside a protective biofilm have been implicated in chronic bacterial UTI and bladder stone formation and may have the advantage of being more resistant to host defenses and antibiotic therapy (29,40). Third, vegetative forms of P. mirabilis (single bacterial cells as opposed to elongated swarming cells) were most often observed in the bladder tissue.…”

Section: Discussionmentioning

confidence: 99%

Use of Green Fluorescent Protein To Assess Urease Gene Expression by Uropathogenic Proteus mirabilis during Experimental Ascending Urinary Tract Infection

Zhao¹,

Thompson²,

Lockatell

et al. 1998

Infect Immun

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Proteus mirabilis, a cause of complicated urinary tract infection, expresses urease when exposed to urea. While it is recognized that the positive transcriptional activator UreR induces gene expression, the levels of expression of the enzyme during experimental infection are not known. To investigate in vivo expression of P. mirabilis urease, the gene encoding green fluorescent protein (GFP) was used to construct reporter fusions. Translational fusions of urease accessory gene ureD, which is preceded by a urea-inducible promoter, were made withgfp (modified to express S65T/V68L/S72A [B. P. Cormack et al. Gene 173:33–38, 1996]). Constructs were confirmed by sequencing of the fusion junctions. UreD-GFP fusion protein was induced by urea in both Escherichia coli DH5α and P. mirabilis HI4320. By using Western blotting with antiserum raised against GFP, expression level was shown to correlate with urea concentration (tested from 0 to 500 mM), with highest induction at 200 to 500 mM urea. Fluorescent E. coli and P. mirabilis bacteria were observed by fluorescence microscopy following urea induction, and the fluorescence intensity of GFP in cell lysates was measured by spectrophotofluorimetry. P. mirabilis HI4320 carrying the UreD-GFP fusion plasmid was transurethrally inoculated into the bladders of CBA mice. One week postchallenge, fluorescent bacteria were detected in thin sections of both bladder and kidney samples; the fluorescence intensity of bacteria in bladder tissue was higher than that in the kidney. Kidneys were primarily infected with single-cell-form fluorescent bacteria, while aggregated bacterial clusters were observed in the bladder. Elongated swarmer cells were only rarely observed. These observations demonstrate that urease is expressed in vivo and that using GFP as a reporter protein is a viable approach to investigate in vivo expression ofP. mirabilis virulence genes in experimental urinary tract infection.

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Section: Discussionmentioning

confidence: 99%

Use of Green Fluorescent Protein To Assess Urease Gene Expression by Uropathogenic Proteus mirabilis during Experimental Ascending Urinary Tract Infection

Zhao¹,

Thompson²,

Lockatell

et al. 1998

Infect Immun

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“…We have proposed that capsule production by infecting organisms is responsible for matrix formation [25]. Testing of this hypothesis awaits the development of acapsular mutants of P. mirabilis and the assessment of their virulence in animal models [29] (in progress). Other investigators propose that the infecting bacteria cause an increased production of GAGs in the urine [43, 46, 47]; however, Hwang et al [19] found no significant difference in GAG levels between normal subjects and patients with stones.…”

Section: Gags and The Struvite Matrixmentioning

confidence: 99%

“…This would suggest that host materials rather than bacterial capsules are the major contributors to matrix formation. Our animal experiments (reviewed in [29]) have shown that any foreign object in the urinary tract is rapidly (< 24 h) colonized by bacteria. It is therefore conceivable that bacterial colonization of metabolic calculus particles such as calcium oxalate may even play a pivotal role in their matrix formation.…”

mentioning

confidence: 99%

Glycosaminoglycans and struvite calculi

McLean

Nickel

1994

World J Urol

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Glycosaminoglycans (GAGs) are suspended in urine and are present on tissue surfaces in the urinary tract. Consequently, they have the potential to influence any pathological disorder in this environment, including urinary tract infections by Proteus mirabilis and struvite (NH4MgPO4.6H2(0)) urolithiasis. Although GAGs, suspended in urine, may inhibit the formation of other types of calculus minerals, no such effect has been reported in struvite calculi. Nevertheless, GAGs are a major component of the organic matrix of all types of urinary calculi. In contrast, there is evidence that the GAG layer on the bladder surface may act as a defence mechanism against infection by inhibiting bacterial adhesion. More studies are needed to elucidate fully the role of GAGs in urinary infections and struvite urolithiasis.

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The Role of Swarm Cell Differentiation and Multicellular Migration in the Uropathogenicity of Proteus mirabilis

Allison¹,

Emödy²,

Coleman³

et al. 1994

The Journal of Infectious Diseases

141

121

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The uropathogenic bacterium Proteus mirabilis displays a form of multicellular behavior called swarming, in which typical vegetative rods differentiate into long hyperflagellate swarm cells that undergo rapid and coordinated population migration across surfaces. Such behavior might inherently assist ascending colonization of the urinary tract, and it has also been shown that swarming differentiation in vitro is central to the expression of conventional virulence factors. This study provides support for a role of swarming in vivo. Mortality rates of mice inoculated intravenously with 2.5 x 10(8) vegetative cells were lower than rates for those inoculated with wild type strains in the case of motile transposon mutants either completely unable to swarm (< 1%) or able to undergo only aberrant swarming migration (< 40%, P < .001). Histologic analysis of renal tissues from mice infected by wild type Proteus strains showed that long differentiated cells were the major cell type, whereas the extracellular inflammatory exudate contained primarily short vegetative cells. Following intravesical (bladder) inoculation with 2.0 x 10(7) vegetative cells, kidney infection was not established by any of the three motile swarm-defective mutants; indeed, the nonswarming mutant was not retained in the bladder. In contrast, the wild type strain and a normally swarming but nonhemolytic mutant achieved a high incidence of ascending infection to the kidney.

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Modelling biofilm-associated urinary tract infections in animals

Cited by 4 publications

References 80 publications

Use of Green Fluorescent Protein To Assess Urease Gene Expression by Uropathogenic Proteus mirabilis during Experimental Ascending Urinary Tract Infection

Use of Green Fluorescent Protein To Assess Urease Gene Expression by Uropathogenic Proteus mirabilis during Experimental Ascending Urinary Tract Infection

Glycosaminoglycans and struvite calculi

The Role of Swarm Cell Differentiation and Multicellular Migration in the Uropathogenicity of Proteus mirabilis

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