BiofilmsA Microbial Life Perspective: A Critical Review

Jain, Aviral; Gupta, Yashwant; Agrawal, Rahul; Khare, Piush; Jain, Sanjay

doi:10.1615/critrevtherdrugcarriersyst.v24.i5.10

Cited by 70 publications

(53 citation statements)

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“…4A), associated with host cell attachment (50). This group contains genes that are involved in controlling the c-di-GMP concentration (51), in generating the biofilm-inhibiting signal indole (52,53), and in forming the extracellular amyloid curli (54), as well as toxin-antitoxin genes that influence biofilm formation and fitness (55).…”

Section: Discussionmentioning

confidence: 99%

PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

et al. 2014

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The metV genomic island in the chromosome of uropathogenic Escherichia coli (UPEC) encodes a putative transcription factor and a sugar permease of the phosphotransferase system (PTS), which are predicted to compose a Bgl-like sensory system. The presence of these two genes, hereby termed pafR and pafP, respectively, has been previously shown to correlate with isolates causing clinical syndromes. We show here that deletion of both genes impairs the ability of the resulting mutant to infect the CBA/J mouse model of ascending urinary tract infection compared to that of the parent strain, CFT073. Expressing the two genes in trans in the two-gene knockout mutant complemented full virulence. Deletion of either gene individually generated the same phenotype as the double knockout, indicating that both pafR and pafP are important to pathogenesis. We screened numerous environmental conditions but failed to detect expression from the promoter that precedes the paf genes in vitro, suggesting that they are in vivo induced (ivi). Although PafR is shown here to be capable of functioning as a transcriptional antiterminator, its targets in the UPEC genome are not known. Using microarray analysis, we have shown that expression of PafR from a heterologous promoter in CFT073 affects expression of genes related to bacterial virulence, biofilm formation, and metabolism. Expression of PafR also inhibits biofilm formation and motility. Taken together, our results suggest that the paf genes are implicated in pathogenesis and that PafR controls virulence genes, in particular biofilm formation genes. U rinary tract infection (UTI) is the most common form of extraintestinal bacterial infection acquired by humans, and uropathogenic Escherichia coli (UPEC) is the most common cause for UTI (1) (2). UPEC colonizes the bladder but may subsequently ascend the ureters and establish a secondary infection in the kidney. Left untreated, UPEC can elicit serious complications, including septicemia and death. Up to 30% of patients with UTI experience recurrent episodes (3). Only a few serogroups of E. coli cause a high proportion of infections. The UPEC strain CFT073, originally isolated from the blood and urine of a patient with acute pyelonephritis (4), is considered a prototype UPEC strain (5, 6). The virulence of CFT073 has been reproduced in the CBA mouse model of ascending UTI (4), where it can cause acute pyelonephritis (7).Sequencing of the CFT073 genome revealed that many of the open reading frames encode hypothetical or putative proteins (8), suggesting that many virulence determinants that play a role in UTI pathogenesis are still unknown. Using comparative genomic hybridization analysis of a panel of uropathogenic and fecal/commensal E. coli isolates, 131 genes were found to be present only in UPEC strains (9). The large number of hypothetical and unannotated genes among these UPEC-specific genes reinforces the notion that many urovirulence factors remain uncharacterized. Significantly, the UPEC-specific genes are not necessarily typical u...

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Section: Discussionmentioning

confidence: 99%

PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

et al. 2014

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“…In the host environment, Candida exists predominantly as biofilms rather than as planktonic cells, especially on indwelling medical devices such as catheters and prostheses (Jain et al, 2007).…”

Section: Induction Of Yeast Bud Formation and Co-aggregationmentioning

confidence: 99%

Fluconazole resistance in Candida glabrata is associated with increased bud formation and metallothionein production

Samaranayake

Cheung

Wang

et al. 2013

Journal of Medical Microbiology

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Virulence associated with fluconazole (FL) resistance in Candida glabrata is a global problem and has not been well characterized at the proteome level. In this study, a stable FL-resistant (MIC .256 mg ml "1 ) strain of C. glabrata was generated on agar containing FL. Eight phenotypic mutants were characterized by contour-clamped homogeneous electrophoretic field analysis and two-dimensional PAGE. The secondary derivatives of C. glabrata yielded four distinct genotypes with varying chromosomal profiles. Proteomic analysis performed by tandem mass spectrometry for two of the mutants, CG L2 and CG S3 , demonstrated a total of 25 differentially regulated proteins of which 13 were upregulated and 12 were downregulated or were similar compared with the parental isolate. The mRNA transcript levels of significantly (P,0.001) upregulated genes were determined by quantitative RT-PCR analysis, and their physiological relevance in terms of phenotypic expression of virulence attributes was verified by conventional laboratory methodologies. The data showed that the FL resistance (MIC .256 mg ml "1 ) of CG S3 was associated with significantly upregulated (P,0.001) mRNA transcript levels of several genes -ERG11, CDR1, CDR2, MFS, MTI, TPR, VPS and EFT2 -in addition to a number of other potentially virulent genes expressed differentially at a lower level. The results demonstrated accentuated phenotypic expression of bud formation of yeast and metallothionein production associated with FL resistance in C. glabrata, which may help the fungus to colonize the host.

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“…Bacterial colonization of surfaces, especially when such colonization progresses to biofilms, reduces the effectiveness of antibiotic therapies 14 and presents a serious problem in biomaterial implants and device surgery. To alleviate this problem, a number of approaches 15 have been proposed to modify surfaces with polymer coatings that are anti-adhesive, 16,17 kill bacteria on contact, 18 elute antimicrobial compounds with time 19 or provide antibacterial protection through enzymatic degradation of a biofilm matrix.…”

Section: Introductionmentioning

confidence: 99%

Small-molecule-hosting nanocomposite films with multiple bacteria-triggered responses

et al. 2014

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We report pH/bacteria-responsive nanocomposite coatings with multiple mechanisms of antibacterial protection that include the permanent retention of antimicrobials, bacteria-triggered release of antibiotics and bacteria-induced film swelling. A novel small-molecule-hosting film was constructed using layer-by-layer deposition of montmorillonite (MMT) clay nanoplatelets and polyacrylic acid (PAA) components, both of which carry a negative charge at neutral pH. The films were highly swollen in water, and they exhibited major changes in swelling as a function of pH. Under physiologic conditions (pH 7.5, 0.2 M NaCl), hydrogel-like MMT/PAA films took up and sequestered B45% of the dry film matrix mass of the antibiotic gentamicin, causing dramatic film deswelling. Gentamicin remained sequestrated within the films for months under physiologic conditions and therefore did not contribute to the development of antibiotic resistance. When challenged with bacteria (Staphylococcus aureus, Staphylococcus epidermidis or Escherichia coli), the coatings released PAA-bound gentamicin because of bacteria-induced acidification of the immediate environment, whereas gentamicin adsorbed to MMT nanoplatelets remained bound within the coating, affording sustained antibacterial protection. Moreover, an increase in film swelling after gentamicin release further hindered bacterial adhesion. These multiple bacteria-triggered responses, together with nontoxicity to tissue cells, make these coatings promising candidates for protecting biomaterial implants and devices against bacterial colonization. INTRODUCTIONPolymer nanocomposites uniquely combine the properties of inorganic and organic components that is central to the development of novel advanced materials. The naturally occurring smectite clays, which are chemically and thermally stable and biocompatible, are attractive nanocomposites. Exfoliated clay nanoplatelets strongly impact the mechanical, transport, optical, fire retardant and gas barrier properties of nanocomposite materials. 1,2 For many biomedical applications, however, hydrophilic rather than hydrophobic nanocomposites are of great interest, and responsive properties are essential. 3 Reports on responsive hydrophilic nanocomposites are rare, and those few known to us advantageously use the complementary properties of temperature/pH-responsive polymers and clay nanosheets to yield environmentally controlled free-standing materials. 4 A promising way to leverage the favorable properties of hydrophilic-responsive nanocomposites on surfaces is to use the layer-by-layer (LbL) technique to construct 'smart' surface coatings. 5 To construct clay-containing LbL films, electrostatic interactions of positively charged polymers with negatively charged basal planes of silicate nanosheets, 6,7 neutral polymer/nanoplatelet hydrogen bonding 8 or a combination of the two have been explored. 9

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BiofilmsA Microbial Life Perspective: A Critical Review

Cited by 70 publications

References 0 publications

PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

Fluconazole resistance in Candida glabrata is associated with increased bud formation and metallothionein production

Small-molecule-hosting nanocomposite films with multiple bacteria-triggered responses

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BiofilmsA Microbial Life Perspective: A Critical Review

Cited by 70 publications

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PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

Fluconazole resistance in Candida glabrata is associated with increased bud formation and metallothionein production

Small-molecule-hosting nanocomposite films with multiple bacteria-triggered responses

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Product

Resources

About

BiofilmsA Microbial Life Perspective: A Critical Review