Ultrastructural stages of biofilm development of Escherichia coli on urethral catheters and effects of antibiotics on biofilm formation

ABSTRACT The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model.

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Regulatory Circuitry of the CsrA/CsrB and BarA/UvrY Systems of Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.184.18.5130-5140.2002 ◽

2002 ◽

Vol 184 (18) ◽

pp. 5130-5140 ◽

Cited By ~ 197

Author(s):

Kazushi Suzuki ◽

Xin Wang ◽

Thomas Weilbacher ◽

Anna-Karin Pernestig ◽

Öjar Melefors ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Rna Binding ◽

Ectopic Expression ◽

Central Carbon Metabolism ◽

Two Component Signal Transduction ◽

Carbon Storage Regulator ◽

Flagellum Biosynthesis ◽

Biofilm Development ◽

Autoregulatory Mechanism

ABSTRACT The global regulator CsrA (carbon storage regulator) is an RNA binding protein that coordinates central carbon metabolism, activates flagellum biosynthesis and motility, and represses biofilm formation in Escherichia coli. CsrA activity is antagonized by the untranslated RNA CsrB, to which it binds and forms a globular ribonucleoprotein complex. CsrA indirectly activates csrB transcription, in an apparent autoregulatory mechanism. In the present study, we elucidate the intermediate regulatory circuitry of this system. Mutations affecting the BarA/UvrY two-component signal transduction system decreased csrB transcription but did not affect csrA′-′lacZ expression. The uvrY defect was severalfold more severe than that of barA. Both csrA and uvrY were required for optimal barA expression. The latter observation suggests an autoregulatory loop for UvrY. Ectopic expression of uvrY suppressed the csrB-lacZ expression defects caused by uvrY, csrA, or barA mutations; csrA suppressed csrA or barA defects; and barA complemented only the barA mutation. Purified UvrY protein stimulated csrB-lacZ expression approximately sixfold in S-30 transcription-translation reactions, revealing a direct effect of UvrY on csrB transcription. Disruption of sdiA, which encodes a LuxR homologue, decreased the expression of uvrY′-′lacZ and csrB-lacZ fusions but did not affect csrA′-′lacZ. The BarA/UvrY system activated biofilm formation. Ectopic expression of uvrY stimulated biofilm formation by a csrB-null mutant, indicative of a CsrB-independent role for UvrY in biofilm development. Collectively, these results demonstrate that uvrY resides downstream from csrA in a signaling pathway for csrB and that CsrA stimulates UvrY-dependent activation of csrB expression by BarA-dependent and -independent mechanisms.

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Aryl Rhodanines Specifically Inhibit Staphylococcal and Enterococcal Biofilm Formation

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00077-09 ◽

2009 ◽

Vol 53 (10) ◽

pp. 4357-4367 ◽

Cited By ~ 32

Author(s):

Timothy J. Opperman ◽

Steven M. Kwasny ◽

John D. Williams ◽

Atiyya R. Khan ◽

Norton P. Peet ◽

...

Keyword(s):

Escherichia Coli ◽

Small Molecules ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Antibiofilm Activity ◽

Bacterial Strains ◽

Gram Negative ◽

Artificial Surfaces ◽

Causative Agents ◽

Biofilm Development

ABSTRACT Staphylococcus epidermidis and Staphylococcus aureus are the leading causative agents of indwelling medical device infections because of their ability to form biofilms on artificial surfaces. Here we describe the antibiofilm activity of a class of small molecules, the aryl rhodanines, which specifically inhibit biofilm formation of S. aureus, S. epidermidis, Enterococcus faecalis, E. faecium, and E. gallinarum but not the gram-negative species Pseudomonas aeruginosa or Escherichia coli. The aryl rhodanines do not exhibit antibacterial activity against any of the bacterial strains tested and are not cytotoxic against HeLa cells. Preliminary mechanism-of-action studies revealed that the aryl rhodanines specifically inhibit the early stages of biofilm development by preventing attachment of the bacteria to surfaces.

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Effect of Escherichia coli Morphogene bolA on Biofilms

Applied and Environmental Microbiology ◽

10.1128/aem.70.9.5682-5684.2004 ◽

2004 ◽

Vol 70 (9) ◽

pp. 5682-5684 ◽

Cited By ~ 47

Author(s):

Helena L. A. Vieira ◽

Patrick Freire ◽

Cecília M. Arraiano

Keyword(s):

Escherichia Coli ◽

Growth Rate ◽

Stationary Phase ◽

Biofilm Formation ◽

Stress Conditions ◽

Biofilm Development

ABSTRACT Biofilm physiology is established under a low growth rate. The morphogene bolA is mostly expressed under stress conditions or in stationary phase, suggesting that bolA could be implicated in biofilm development. In order to verify this hypothesis, we tested the effect of bolA on biofilm formation. Overexpression of bolA induces biofilm development, while bolA deletion decreases biofilms.

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Bundle-Forming Pili and EspA Are Involved in Biofilm Formation by Enteropathogenic Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.00177-06 ◽

2006 ◽

Vol 188 (11) ◽

pp. 3952-3961 ◽

Cited By ~ 53

Author(s):

Cristiano G. Moreira ◽

Kelli Palmer ◽

Marvin Whiteley ◽

Marcelo P. Sircili ◽

Luiz R. Trabulsi ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Signaling Mechanism ◽

Bacterial Aggregation ◽

Abiotic Surfaces ◽

Genes Encoding ◽

Continuous Culture System ◽

Static Conditions ◽

Biofilm Development ◽

Isogenic Mutants

ABSTRACT Microcolony formation is one of the initial steps in biofilm development, and in enteropathogenic Escherichia coli (EPEC) it is mediated by several adhesins, including the bundle-forming pilus (BFP) and the EspA filament. Here we report that EPEC forms biofilms on plastic under static conditions and a flowthrough continuous culture system. The abilities of several EPEC isogenic mutants to form biofilms were assessed. Adhesins such as BFP and EspA, important in microcolony formation on epithelial cells, are also involved in bacterial aggregation during biofilm formation on abiotic surfaces. Mutants that do not express BFP or EspA form more-diffuse biofilms than does the wild type. We also determined, using gfp transcriptional fusions, that, consistent with the role of these adhesins in biofilms, the genes encoding BFP and EspA are expressed during biofilm formation. Finally, expression of espA is controlled by a quorum-sensing (QS) regulatory mechanism, and the EPEC qseA QS mutant also forms altered biofilms, suggesting that this signaling mechanism plays an important role in EPEC biofilm development. Taken together, these studies allowed us to propose a model of EPEC biofilm formation.

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Regulation of type 1 fimbriae synthesis and biofilm formation by the transcriptional regulator LrhA of Escherichia coli

Microbiology ◽

10.1099/mic.0.28098-0 ◽

2005 ◽

Vol 151 (10) ◽

pp. 3287-3298 ◽

Cited By ~ 76

Author(s):

Caroline Blumer ◽

Alexandra Kleefeld ◽

Daniela Lehnen ◽

Margit Heintz ◽

Ulrich Dobrindt ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Invertible Element ◽

Transcriptional Regulator ◽

Host Cells ◽

Yeast Cells ◽

Type 1 Fimbriae ◽

Biofilm Development

Type 1 fimbriae of Escherichia coli facilitate attachment to the host mucosa and promote biofilm formation on abiotic surfaces. The transcriptional regulator LrhA, which is known as a repressor of flagellar, motility and chemotaxis genes, regulates biofilm formation and expression of type 1 fimbriae. Whole-genome expression profiling revealed that inactivation of lrhA results in an increased expression of structural components of type 1 fimbriae. In vitro, LrhA bound to the promoter regions of the two fim recombinases (FimB and FimE) that catalyse the inversion of the fimA promoter, and to the invertible element itself. Translational lacZ fusions with these genes and quantification of fimE transcript levels by real-time PCR showed that LrhA influences type 1 fimbrial phase variation, primarily via activation of FimE, which is required for the ON-to-OFF transition of the fim switch. Enhanced type 1 fimbrial expression as a result of lrhA disruption was confirmed by mannose-sensitive agglutination of yeast cells. Biofilm formation was stimulated by lrhA inactivation and completely suppressed upon LrhA overproduction. The effects of LrhA on biofilm formation were exerted via the changed levels of surface molecules, most probably both flagella and type 1 fimbriae. Together, the data show a role for LrhA as a repressor of type 1 fimbrial expression, and thus as a regulator of the initial stages of biofilm development and, presumably, bacterial adherence to epithelial host cells also.

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Mat fimbriae promote biofilm formation by meningitis-associated Escherichia coli

Microbiology ◽

10.1099/mic.0.039610-0 ◽

2010 ◽

Vol 156 (8) ◽

pp. 2408-2417 ◽

Cited By ~ 18

Author(s):

Timo A. Lehti ◽

Philippe Bauchart ◽

Johanna Heikkinen ◽

Jörg Hacker ◽

Timo K. Korhonen ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Early Stage ◽

Surface Expression ◽

Growth Media ◽

Biofilm Growth ◽

Abiotic Surfaces ◽

K 12 ◽

Biofilm Development

The mat (or ecp) fimbrial operon is ubiquitous and conserved in Escherichia coli, but its functions remain poorly described. In routine growth media newborn meningitis isolates of E. coli express the meningitis-associated and temperature-regulated (Mat) fimbria, also termed E. coli common pilus (ECP), at 20 °C, and here we show that the six-gene (matABCDEF)-encoded Mat fimbria is needed for temperature-dependent biofilm formation on abiotic surfaces. The matBCDEF deletion mutant of meningitis E. coli IHE 3034 was defective in an early stage of biofilm development and consequently unable to establish a detectable biofilm, contrasting with IHE 3034 derivatives deleted for flagella, type 1 fimbriae or S-fimbriae, which retained the wild-type biofilm phenotype. Furthermore, induced production of Mat fimbriae from expression plasmids enabled biofilm-deficient E. coli K-12 cells to form biofilm at 20 °C. No biofilm was detected with IHE 3034 or MG1655 strains grown at 37 °C. The surface expression of Mat fimbriae and the frequency of Mat-positive cells in the IHE 3034 population from 20 °C were high and remained unaltered during the transition from planktonic to biofilm growth and within the matured biofilm community. Considering the prevalence of the highly conserved mat locus in E. coli genomes, we hypothesize that Mat fimbria-mediated biofilm formation is an ancestral characteristic of E. coli.

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Genome-Wide Transposon Mutagenesis Reveals a Role for pO157 Genes in Biofilm Development in Escherichia coli O157:H7 EDL933

Infection and Immunity ◽

10.1128/iai.00156-10 ◽

2010 ◽

Vol 78 (6) ◽

pp. 2377-2384 ◽

Cited By ~ 49

Author(s):

Supraja Puttamreddy ◽

Nancy A. Cornick ◽

F. Chris Minion

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Microtiter Plate ◽

Virulence Plasmid ◽

Microtiter Plate Assay ◽

Severe Diarrhea ◽

Wide Range ◽

Intergenic Regions ◽

Biofilm Development

ABSTRACT Enterohemorrhagic Escherichia coli O157:H7, a world-wide human food-borne pathogen, causes mild to severe diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. The ability of this pathogen to persist in the environment contributes to its dissemination to a wide range of foods and food processing surfaces. Biofilms are thought to be involved in persistence, but the process of biofilm formation is complex and poorly understood in E. coli O157:H7. To better understand the genetics of this process, a mini-Tn5 transposon insertion library was constructed in strain EDL933 and screened for biofilm-negative mutants using a microtiter plate assay. Ninety-five of 11,000 independent insertions (0.86%) were biofilm negative, and transposon insertions were located in 51 distinct genes/intergenic regions that must be involved either directly or indirectly in biofilm formation. All of the 51 biofilm-negative mutants showed reduced biofilm formation on both hydrophilic and hydrophobic surfaces. Thirty-six genes were unique to this study, including genes on the virulence plasmid pO157. The type V secreted autotransporter serine protease EspP and the enterohemolysin translocator EhxD were found to be directly involved in biofilm formation. In addition, EhxD and EspP were also important for adherence to T84 intestinal epithelial cells, suggesting a role for these genes in tissue interactions in vivo.

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Rcs phosphorelay activation in cardiolipin-deficient Escherichia coli reduces biofilm formation

10.1101/522219 ◽

2019 ◽

Cited By ~ 1

Author(s):

Julia F. Nepper ◽

Yin C. Lin ◽

Douglas B. Weibel

Keyword(s):

Escherichia Coli ◽

Stress Response ◽

Biofilm Formation ◽

Lipid Membrane ◽

Protein Translocation ◽

Membrane Composition ◽

Anionic Phospholipid ◽

Envelope Stress ◽

Biofilm Development

AbstractBiofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation in Escherichia coli cells by as much as 50%. The absence of cardiolipin activates the Rcs envelope stress response, which represses production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation in E. coli and suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.ImportanceThere is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation in Escherichia coli cells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development, and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.

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Biofilm Formation and Dispersal under the Influence of the Global Regulator CsrA of Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.184.1.290-301.2002 ◽

2002 ◽

Vol 184 (1) ◽

pp. 290-301 ◽

Cited By ~ 279

Author(s):

Debra W. Jackson ◽

Kazushi Suzuki ◽

Lawrence Oakford ◽

Jerry W. Simecka ◽

Mark E. Hart ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Rna Binding ◽

Glycogen Synthase ◽

Regulatory Protein ◽

Ectopic Expression ◽

Knockout Mutant ◽

E Coli ◽

K 12 ◽

Biofilm Development

ABSTRACT The predominant mode of growth of bacteria in the environment is within sessile, matrix-enclosed communities known as biofilms. Biofilms often complicate chronic and difficult-to-treat infections by protecting bacteria from the immune system, decreasing antibiotic efficacy, and dispersing planktonic cells to distant body sites. While the biology of bacterial biofilms has become a major focus of microbial research, the regulatory mechanisms of biofilm development remain poorly defined and those of dispersal are unknown. Here we establish that the RNA binding global regulatory protein CsrA (carbon storage regulator) of Escherichia coli K-12 serves as both a repressor of biofilm formation and an activator of biofilm dispersal under a variety of culture conditions. Ectopic expression of the E. coli K-12 csrA gene repressed biofilm formation by related bacterial pathogens. A csrA knockout mutation enhanced biofilm formation in E. coli strains that were defective for extracellular, surface, or regulatory factors previously implicated in biofilm formation. In contrast, this csrA mutation did not affect biofilm formation by a glgA (glycogen synthase) knockout mutant. Complementation studies with glg genes provided further genetic evidence that the effects of CsrA on biofilm formation are mediated largely through the regulation of intracellular glycogen biosynthesis and catabolism. Finally, the expression of a chromosomally encoded csrA′-′lacZ translational fusion was dynamically regulated during biofilm formation in a pattern consistent with its role as a repressor. We propose that global regulation of central carbon flux by CsrA is an extremely important feature of E. coli biofilm development.

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