Cellular chain formation in Escherichia coli biofilms

Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1407-1417 ◽  
Author(s):  
Rebecca Munk Vejborg ◽  
Per Klemm
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Immunofluorescence Microscopy ◽  
Asymptomatic Bacteriuria ◽  
Type I ◽  
Chain Formation ◽  
Biofilm Growth ◽  
E Coli ◽  
Type I Fimbriae ◽  
K 12

In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular interactions facilitated by antigen 43 (Ag43), a self-associating autotransporter (SAAT) protein, which has previously been implicated in auto-aggregation and biofilm formation. Immunofluorescence microscopy suggested that Ag43 was concentrated at or near the cell poles, although when the antigen was highly overexpressed, a much more uniform distribution was seen. Immunofluorescence microscopy also indicated that other parameters, including dimensional constraints (flow, growth alongside a surface), may also affect the final biofilm architecture. Moreover, chain formation was affected by other surface structures; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E. coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates, including the prototypic asymptomatic bacteriuria strain, 83972, formed highly elaborate cellular chains during biofilm growth in human urine. Combined, these results illustrate the diversity of biofilm architectures that can be observed even within a single microbial species.

scholarly journals IscR Controls Iron-Dependent Biofilm Formation in Escherichia coli by Regulating Type I Fimbria Expression

2008 ◽  
Vol 191 (4) ◽  
pp. 1248-1257 ◽  
Author(s):  
Yun Wu ◽  
F. Wayne Outten
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Developmental Process ◽  
Bacterial Species ◽  
Type I ◽  
Surface Attachment ◽  
Environmental Signals ◽  
Regulatory Pathways ◽  
E Coli ◽  
Type I Fimbriae

ABSTRACT Biofilm formation is a complex developmental process regulated by multiple environmental signals. In addition to other nutrients, the transition metal iron can also regulate biofilm formation. Iron-dependent regulation of biofilm formation varies by bacterial species, and the exact regulatory pathways that control iron-dependent biofilm formation are often unknown or only partially characterized. To address this gap in our knowledge, we examined the role of iron availability in regulating biofilm formation in Escherichia coli. The results indicate that biofilm formation is repressed under low-iron conditions in E. coli. Furthermore, a key iron regulator, IscR, controls biofilm formation in response to changes in cellular Fe-S homeostasis. IscR regulates the FimE recombinase to control expression of type I fimbriae in E. coli. We propose that iron-dependent regulation of FimE via IscR leads to decreased surface attachment and biofilm dispersal under iron-limiting conditions.

scholarly journals Global Gene Expression Profiling of Asymptomatic Bacteriuria Escherichia coli during Biofilm Growth in Human Urine

2006 ◽  
Vol 75 (2) ◽  
pp. 966-976 ◽  
Author(s):  
Viktoria Hancock ◽  
Per Klemm
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Expression Profile ◽  
Human Urine ◽  
Biofilm Formation ◽  
Expression Profiles ◽  
Asymptomatic Bacteriuria ◽  
Knockout Mutant ◽  
Biofilm Growth ◽  
E Coli

ABSTRACT Urinary tract infection (UTI) is an important health problem worldwide, with many millions of cases each year, and Escherichia coli is the most common organism causing UTI in humans. Also, E. coli is responsible for most infections in patients with chronic indwelling bladder catheter. The two asymptomatic bacteriuria (ABU) E. coli strains 83972 and VR50 are significantly better biofilm formers in their natural growth medium, human urine, than the two uropathogenic E. coli isolates CFT073 and 536. We used DNA microarrays to monitor the expression profile during biofilm growth in urine of the two ABU strains 83972 and VR50. Significant differences in expression levels were seen between the biofilm expression profiles of the two strains with the corresponding planktonic expression profiles in morpholinepropanesulfonic acid minimal laboratory medium and human urine; 417 and 355 genes were up- and down-regulated, respectively, during biofilm growth in urine of 83972 and VR50. Many genes involved in transcription and stress were up-regulated in biofilm-grown cells. The role in biofilm formation of four of the up-regulated genes, i.e., yceP, yqgA, ygiD, and aaeX, was investigated by creating single-knockout mutant versions of 83972 and VR50; all mutants showed reduced biofilm formation in urine by 18 to 43% compared with the wild type (P < 0.05). Also, the expression profile of strain 83972 in the human urinary tract partially overlaps with the biofilm expression profile.

scholarly journals Influence of Type I Fimbriae and Fluid Shear Stress on Bacterial Behavior and Multicellular Architecture of Early Escherichia coli Biofilms at Single-Cell Resolution

2018 ◽  
Vol 84 (6) ◽  
Author(s):  
Liyun Wang ◽  
Robert Keatch ◽  
Qi Zhao ◽  
John A. Wright ◽  
Clare E. Bryant ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shear Stress ◽  
Single Cell ◽  
Biofilm Formation ◽  
Fluid Shear Stress ◽  
Cell Membrane Permeability ◽  
Type I ◽  
Fluid Shear ◽  
Content Type ◽  
Type I Fimbriae

ABSTRACT Biofilm formation on abiotic surfaces in the food and medical industry can cause severe contamination and infection, yet how biological and physical factors determine the cellular architecture of early biofilms and the bacterial behavior of the constituent cells remains largely unknown. In this study, we examined the specific role of type I fimbriae in nascent stages of biofilm formation and the response of microcolonies to environmental flow shear at the single-cell resolution. The results show that type I fimbriae are not required for reversible adhesion from plankton, but they are critical for the irreversible adhesion of Escherichia coli strain MG1655 cells that form biofilms on polyethylene terephthalate (PET) surfaces. Besides establishing firm cell surface contact, the irreversible adhesion seems necessary to initiate the proliferation of E. coli on the surface. After the application of shear stress, bacterial retention is dominated by the three-dimensional architecture of colonies, independent of the population size, and the multilayered structure could protect the embedded cells from being insulted by fluid shear, while the cell membrane permeability mainly depends on the biofilm population size and the duration of the shear stress. IMPORTANCE Bacterial biofilms could lead to severe contamination problems in medical devices and food processing equipment. However, biofilms are usually studied at a rough macroscopic level; thus, little is known about how individual bacterium behavior within biofilms and the multicellular architecture are influenced by bacterial appendages (e.g., pili/fimbriae) and environmental factors during early biofilm formation. We applied confocal laser scanning microscopy (CLSM) to visualize Escherichia coli microcolonies at a single-cell resolution. Our findings suggest that type I fimbriae are vital to the initiation of bacterial proliferation on surfaces. We also found that the fluid shear stress affects the biofilm architecture and cell membrane permeability of the constituent bacteria in a different way: the onset of the biofilm is linked with the three-dimensional morphology, while membranes are regulated by the overall population of microcolonies.

scholarly journals Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Kelvin G. K. Goh ◽  
Danilo G. Moriel ◽  
Steven J. Hancock ◽  
Minh-Duy Phan ◽  
Mark A. Schembri
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Secretion System ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Type V Secretion ◽  
K 12 ◽  
Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli

2019 ◽  
Vol 65 (9) ◽  
pp. 691-702 ◽  
Author(s):  
Yi Gou ◽  
Weiqi Liu ◽  
Jing Jing Wang ◽  
Ling Tan ◽  
Bin Hong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Motility ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Signal Transmission ◽  
Bacterial Motility ◽  
Type I ◽  
E Coli ◽  
Real Time Quantitative Pcr ◽  
In The Wild

Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.

scholarly journals Nickel Promotes Biofilm Formation by Escherichia coli K-12 Strains That Produce Curli

2009 ◽  
Vol 75 (6) ◽  
pp. 1723-1733 ◽  
Author(s):  
Claire Perrin ◽  
Romain Briandet ◽  
Gregory Jubelin ◽  
Philippe Lejeune ◽  
Marie-Andrée Mandrand-Berthelot ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Selective Advantage ◽  
Bacterial Survival ◽  
Toxic Compounds ◽  
E Coli ◽  
Transcriptional Effect ◽  
K 12 ◽  
Encoding Genes

ABSTRACT The survival of bacteria exposed to toxic compounds is a multifactorial phenomenon, involving well-known molecular mechanisms of resistance but also less-well-understood mechanisms of tolerance that need to be clarified. In particular, the contribution of biofilm formation to survival in the presence of toxic compounds, such as nickel, was investigated in this study. We found that a subinhibitory concentration of nickel leads Escherichia coli bacteria to change their lifestyle, developing biofilm structures rather than growing as free-floating cells. Interestingly, whereas nickel and magnesium both alter the global cell surface charge, only nickel promotes biofilm formation in our system. Genetic evidence indicates that biofilm formation induced by nickel is mediated by the transcriptional induction of the adhesive curli-encoding genes. Biofilm formation induced by nickel does not rely on efflux mechanisms using the RcnA pump, as these require a higher concentration of nickel to be activated. Our results demonstrate that the nickel-induced biofilm formation in E. coli is an adaptational process, occurring through a transcriptional effect on genes coding for adherence structures. The biofilm lifestyle is obviously a selective advantage in the presence of nickel, but the means by which it improves bacterial survival needs to be investigated.

scholarly journals Mat fimbriae promote biofilm formation by meningitis-associated Escherichia coli

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2408-2417 ◽  
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.

scholarly journals The Transcriptional Antiterminator RfaH Represses Biofilm Formation in Escherichia coli

2006 ◽  
Vol 188 (4) ◽  
pp. 1316-1331 ◽  
Author(s):  
Christophe Beloin ◽  
Kai Michaelis ◽  
Karin Lindner ◽  
Paolo Landini ◽  
Jörg Hacker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Wild Type Strain ◽  
Wild Type ◽  
Strain Mg1655 ◽  
Upec Strain ◽  
E Coli ◽  
Initial Adhesion ◽  
State Production ◽  
K 12

ABSTRACT We investigated the influence of regulatory and pathogenicity island-associated factors (Hha, RpoS, LuxS, EvgA, RfaH, and tRNA5 Leu) on biofilm formation by uropathogenic Escherichia coli (UPEC) strain 536. Only inactivation of rfaH, which encodes a transcriptional antiterminator, resulted in increased initial adhesion and biofilm formation by E. coli 536. rfaH inactivation in nonpathogenic E. coli K-12 isolate MG1655 resulted in the same phenotype. Transcriptome analysis of wild-type strain 536 and an rfaH mutant of this strain revealed that deletion of rfaH correlated with increased expression of flu orthologs. flu encodes antigen 43 (Ag43), which mediates autoaggregation and biofilm formation. We confirmed that deletion of rfaH leads to increased levels of flu and flu-like transcripts in E. coli K-12 and UPEC. Supporting the hypothesis that RfaH represses biofilm formation through reduction of the Ag43 level, the increased-biofilm phenotype of E. coli MG1655rfaH was reversed upon inactivation of flu. Deletion of the two flu orthologs, however, did not modify the behavior of mutant 536rfaH. Our results demonstrate that the strong initial adhesion and biofilm formation capacities of strain MG1655rfaH are mediated by both increased steady-state production of Ag43 and likely increased Ag43 presentation due to null rfaH-dependent lipopolysaccharide depletion. Although the roles of rfaH in the biofilm phenotype are different in UPEC strain 536 and K-12 strain MG1655, this study shows that RfaH, in addition to affecting the expression of bacterial virulence factors, also negatively controls expression and surface presentation of Ag43 and possibly another Ag43-independent factor(s) that mediates cell-cell interactions and biofilm formation.

scholarly journals Identification of Type 3 Fimbriae in Uropathogenic Escherichia coli Reveals a Role in Biofilm Formation

2007 ◽  
Vol 190 (3) ◽  
pp. 1054-1063 ◽  
Author(s):  
Cheryl-Lynn Y. Ong ◽  
Glen C. Ulett ◽  
Amanda N. Mabbett ◽  
Scott A. Beatson ◽  
Richard I. Webb ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Klebsiella Oxytoca ◽  
The United States ◽  
Conjugative Plasmid ◽  
Biofilm Growth ◽  
Indwelling Catheters ◽  
E Coli ◽  
Type 3

ABSTRACT Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States. Uropathogenic Escherichia coli (UPEC), the most common cause of CAUTI, can form biofilms on indwelling catheters. Here, we identify and characterize novel factors that affect biofilm formation by UPEC strains that cause CAUTI. Sixty-five CAUTI UPEC isolates were characterized for phenotypic markers of urovirulence, including agglutination and biofilm formation. One isolate, E. coli MS2027, was uniquely proficient at biofilm growth despite the absence of adhesins known to promote this phenotype. Mini-Tn5 mutagenesis of E. coli MS2027 identified several mutants with altered biofilm growth. Mutants containing insertions in genes involved in O antigen synthesis (rmlC and manB) and capsule synthesis (kpsM) possessed enhanced biofilm phenotypes. Three independent mutants deficient in biofilm growth contained an insertion in a gene locus homologous to the type 3 chaperone-usher class fimbrial genes of Klebsiella pneumoniae. These type 3 fimbrial genes (mrkABCDF), which were located on a conjugative plasmid, were cloned from E. coli MS2027 and could complement the biofilm-deficient transconjugants when reintroduced on a plasmid. Primers targeting the mrkB chaperone-encoding gene revealed its presence in CAUTI strains of Citrobacter koseri, Citrobacter freundii, Klebsiella pneumoniae, and Klebsiella oxytoca. All of these mrkB-positive strains caused type 3 fimbria-specific agglutination of tannic acid-treated red blood cells. This is the first description of type 3 fimbriae in E. coli, C. koseri, and C. freundii. Our data suggest that type 3 fimbriae may contribute to biofilm formation by different gram-negative nosocomial pathogens.

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

2004 ◽  
Vol 72 (4) ◽  
pp. 1929-1938 ◽  
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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