scholarly journals Biofilm Formation in a Hydrodynamic Environment by Novel FimH Variants and Ramifications for Virulence

2001 ◽  
Vol 69 (3) ◽  
pp. 1322-1328 ◽  
Author(s):  
Mark A. Schembri ◽  
Per Klemm

ABSTRACT Type 1 fimbriae are surface-located adhesion organelles ofEscherichia coli that are directly associated with virulence of the urinary tract. They mediated-mannose-sensitive binding to different host surfaces by way of the minor fimbrial component FimH. Naturally occurring variants of FimH that bind strongly to terminally exposed monomannose residues have been associated with a pathogenicity-adaptive phenotype that enhances E. coli colonization of extraintestinal locations such as the urinary tract. The FimH adhesin also promotes biofilm formation in a mannose-inhibitable manner on abiotic surfaces under static growth conditions. In this study, we used random mutagenesis combined with a novel selection-enrichment technique to specifically identify mutations in the FimH adhesin that confer onE. coli the ability to form biofilms under hydrodynamic flow (HDF) conditions. We identified three FimH variants from our mutant library that could mediate an HDF biofilm formation phenotype to various degrees. This phenotype was induced by the cumulative effect of multiple changes throughout the receptor-binding region of the protein. Two of the HDF biofilm-forming FimH variants were insensitive to mannose inhibition and represent novel phenotypes not previously identified in naturally occurring isolates. Characterization of our enriched clones revealed some similarities to amino acid alterations that occur in urinary tract infection (UTI) strains. Subsequent screening of a selection of UTI FimH variants demonstrated that they too could promote biofilm formation on abiotic surfaces under HDF conditions. Interestingly, the same correlation was not observed for commensal FimH variants. FimH is a multifaceted protein prone to rapid microevolution. In addition to its previously documented roles in adherence and invasion, we have now demonstrated its function in biofilm formation on abiotic surfaces subjected to HDF conditions. The study indicates that UTI FimH variants possess adaptations that enhance biofilm formation and suggests a novel role for FimH in UTIs associated with medical implants such as catheters.

2004 ◽  
Vol 186 (23) ◽  
pp. 8058-8065 ◽  
Author(s):  
Orla Sherlock ◽  
Mark A. Schembri ◽  
Andreas Reisner ◽  
Per Klemm

ABSTRACT Diarrhea-causing Escherichia coli strains are responsible for numerous cases of gastrointestinal disease and constitute a serious health problem throughout the world. The ability to recognize and attach to host intestinal surfaces is an essential step in the pathogenesis of such strains. AIDA is a potent bacterial adhesin associated with some diarrheagenic E. coli strains. AIDA mediates bacterial attachment to a broad variety of human and other mammalian cells. It is a surface-displayed autotransporter protein and belongs to the selected group of bacterial glycoproteins; only the glycosylated form binds to mammalian cells. Here, we show that AIDA possesses self-association characteristics and can mediate autoaggregation of E. coli cells. We demonstrate that intercellular AIDA-AIDA interaction is responsible for bacterial autoaggregation. Interestingly, AIDA-expressing cells can interact with antigen 43 (Ag43)-expressing cells, which is indicative of an intercellular AIDA-Ag43 interaction. Additionally, AIDA expression dramatically enhances biofilm formation by E. coli on abiotic surfaces in flow chambers.


2016 ◽  
Vol 198 (19) ◽  
pp. 2662-2672 ◽  
Author(s):  
Kyle A. Floyd ◽  
Courtney A. Mitchell ◽  
Allison R. Eberly ◽  
Spencer J. Colling ◽  
Ellisa W. Zhang ◽  
...  

ABSTRACTUropathogenicEscherichia coli(UPEC), which causes the majority of urinary tract infections (UTI), uses pilus-mediated adherence to initiate biofilm formation in the urinary tract. Oxygen gradients withinE. colibiofilms regulate expression and localization of adhesive type 1 pili. A transposon mutant screen for strains defective in biofilm formation identified theubiI(formerlyvisC) aerobic ubiquinone synthase gene as critical for UPEC biofilm formation. In this study, we characterized a nonpolarubiIdeletion mutant and compared its behavior to that of wild-type bacteria grown under aerobic and anoxic conditions. Consistent with its function as an aerobic ubiquinone-8 synthase, deletion ofubiIin UPEC resulted in reduced membrane potential, diminished motility, and reduced expression of chaperone-usher pathway pili. Loss of aerobic respiration was previously shown to negatively impact expression of type 1 pili. To determine whether this reduction in type 1 pili was due to an energy deficit, wild-type UPEC and theubiImutant were compared for energy-dependent phenotypes under anoxic conditions, in which quinone synthesis is undertaken by anaerobic quinone synthases. Under anoxic conditions, the two strains exhibited wild-type levels of motility but produced diminished numbers of type 1 pili, suggesting that the reduction of type 1 pilus expression in the absence of oxygen is not due to a cellular energy deficit. Acute- and chronic-infection studies in a mouse model of UTI revealed a significant virulence deficit in theubiImutant, indicating that UPEC encounters enough oxygen in the bladder to induce aerobic ubiquinone synthesis during infection.IMPORTANCEThe majority of urinary tract infections are caused by uropathogenicE. coli, a bacterium that can respire in the presence and absence of oxygen. The bladder environment is hypoxic, with oxygen concentrations ranging from 4% to 7%, compared to 21% atmospheric oxygen. This work provides evidence that aerobic ubiquinone synthesis must be engaged during bladder infection, indicating that UPEC bacteria sense and use oxygen as a terminal electron acceptor in the bladder and that this ability drives infection potential despite the fact that UPEC is a facultative anaerobe.


2010 ◽  
Vol 76 (12) ◽  
pp. 3836-3841 ◽  
Author(s):  
Viktoria Hancock ◽  
Malin Dahl ◽  
Per Klemm

ABSTRACT Bacterial biofilms are associated with a large number of persistent and chronic infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics and immune defenses, which makes it hard if not impossible to eradicate biofilm-associated infections. In the urinary tract, free iron is strictly limited but is critical for bacterial growth. Biofilm-associated Escherichia coli cells are particularly desperate for iron. An attractive way of inhibiting biofilm formation is to fool the bacterial regulatory system for iron uptake. Here, we demonstrate that biofilm formation can be impaired by the addition of divalent metal ions, such as Zn(II) and Co(II), which inhibit iron uptake by virtue of their higher-than-iron affinity for the master controller protein of iron uptake, Fur. Reduced biofilm formation of urinary tract-infectious E. coli strains in the presence of Zn(II) was observed in microtiter plates and flow chambers as well as on urinary catheters. These results further support that iron uptake is indeed crucial for biofilm formation, and thereby, targeting these uptake systems might be an effective way to eradicate biofilms caused by infectious strains.


2019 ◽  
Vol 4 (2) ◽  
pp. 58
Author(s):  
Christofer Sathya Wijaya Budi Sarwono

Background: Antibiotic resistance currently challenges infectious disease management, specifically in combating biofilm formation. Biofilm might be developed on urinary catheter, in which stroke patients with urinary tract problem have higher risk of catheter associated urinary tract infection and problems related to antibiotic resistance. Aim: This study describes the microbe types from catheter isolates, measuring the antibiotic susceptibility and biofilm formation, especially in stroke patients at Bethesda Hospital, Yogyakarta. Method: This is a cross-sectional study, describing findings of specimens from stroke patients at Bethesda Hospital, since December 2018 to January 2019. The isolates were identified with standard method, the antibiotic susceptibility were tested with antibiotic disc on MHA medium, and the biofilm formation were assessed using tissue culture plate method. All procedure were done in Microbiology Laboratorium, FK UKDW. Result: Thirty three microbes were isolated from 30 specimens of urinary catheter (63,3% male, 36,3% female). There is 76% isolates incapable of developing biofilm, while 15% is moderate biofilm producer and 9% is strong biofilm producer. The susceptibility test showed 100% resistancy of ampicillin-sulbactam, tetracyclin, ketoconazole, itraconazole, and terbinafine. Around 50% of E. coli and 57% of K. pneumonias isolates is MDR, and 75% of A. baumanii is XDR. Conclusion: Isolated microbes from urinary catheter of stroke patients at Bethesda Hospital is dominated by E. coli, K. pneumoniae, and A. baumanii. Some of the microbes could form strong biofilm, and some of the antibiotics could not be used in the future due to their 100% resistancy on all specimens.


Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 722 ◽  
Author(s):  
Pennone ◽  
Sanz-Gaitero ◽  
O’Connor ◽  
Coffey ◽  
Jordan ◽  
...  

Listeria monocytogenes is a ubiquitous Gram-positive bacterium that is a major concern for food business operators because of its pathogenicity and ability to form biofilms in food production environments. Bacteriophages (phages) have been evaluated as biocontrol agents for L. monocytogenes in a number of studies and, indeed, certain phages have been approved for use as anti-listerial agents in food processing environments (ListShield and PhageGuard Listex). Endolysins are proteins produced by phages in the host cell. They cleave the peptidoglycan cell wall, thus allowing release of progeny phage into the environment. In this study, the amidase domain of the phage vB_LmoS_293 endolysin (293-amidase) was cloned and expressed in Escherichia. coli (E. coli). Muralytic activity at different concentrations, pH and temperature values, lytic spectrum and activity against biofilms was determined for the purified 293-amidase protein. The results showed activity on autoclaved cells at three different temperatures (20 °C, 37 °C and 50 °C), with a wider specificity (L. monocytogenes 473 and 3099, a serotype 4b and serogroup 1/2b-3b-7, respectively) compared to the phage itself, which targets only L. monocytogenes serotypes 4b and 4e. The protein also inhibits biofilm formation on abiotic surfaces. These results show the potential of using recombinant antimicrobial proteins against pathogens in the food production environment.


Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 885
Author(s):  
Mariarita Stirpe ◽  
Benedetta Brugnoli ◽  
Gianfranco Donelli ◽  
Iolanda Francolini ◽  
Claudia Vuotto

Poloxamers are nontoxic, amphiphilic copolymers used in different formulations. Due to its surfactant properties, Poloxamer 338 (P388) is herein proposed as a strategy to avoid biofilm formation often causing recalcitrant catheter-associated urinary tract infections (CAUTI). The aim is to evaluate the ability of P388 coatings to affect the adhesion of Ec5FSL and Ec9FSL Escherichia coli strains on silicone urinary catheters. Attenuated total reflection infrared spectroscopy, atomic force microscopy, and static water contact angle measurement were employed to characterize the P388-coated silicone catheter in terms of amount of P388 layered, coating thickness, homogeneity, and hydrophilicity. In static conditions, the antifouling power of P388 was defined by comparing the E. coli cells adherent on a hydrophilic P388-adsorbed catheter segment with those on an uncoated one. A P388-coated catheter, having a homogeneous coverage of 35 nm in thickness, reduced of 0.83 log10 and 0.51 log10 the biofilm of Ec5FSL and Ec9FSL, respectively. In dynamic conditions, the percentage of cell adhesion on P388-adsorbed silicone channels was investigated by a microfluidic system, simulating the in vivo conditions of catheterized patients. As a result, both E. coli isolates were undetected. The strong and stable antifouling property against E. coli biofilm lead us to consider P388 as a promising anti-biofilm agent for CAUTIs control.


Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 304 ◽  
Author(s):  
Beata Zalewska-Piątek ◽  
Rafał Piątek

Urinary tract infections (UTIs) are regarded as one of the most common bacterial infections affecting millions of people, in all age groups, annually in the world. The major causative agent of complicated and uncomplicated UTIs are uropathogenic E. coli strains (UPECs). Huge problems with infections of this type are their chronicity and periodic recurrences. Other disadvantages that are associated with UTIs are accompanying complications and high costs of health care, systematically increasing resistance of uropathogens to routinely used antibiotics, as well as biofilm formation by them. This creates the need to develop new approaches for the prevention and treatment of UTIs, among which phage therapy has a dominant potential to eliminate uropathogens within urinary tract. Due to the growing interest in such therapy in the last decade, the bacteriophages (natural, genetically modified, engineered, or combined with antibiotics or disinfectants) represent an innovative antimicrobial alternative and a strategy for managing the resistance of uropathogenic microorganisms and controlling UTIs.


2005 ◽  
Vol 73 (4) ◽  
pp. 1954-1963 ◽  
Author(s):  
Orla Sherlock ◽  
Rebecca Munk Vejborg ◽  
Per Klemm

ABSTRACT Escherichia coli strains are responsible for many cases of gastrointestinal disease and represent a serious health problem worldwide. An essential step in the pathogenesis of such strains involves recognition and attachment to host intestinal surfaces. TibA is a potent bacterial adhesin associated with a number of enterotoxigenic E. coli strains and mediates bacterial attachment to a variety of human cells; additionally, it promotes invasion of such cells. This adhesin is a surface-displayed autotransporter protein and belongs to the exclusive group of bacterial glycoproteins; only the glycosylated form confers binding to and invasion of mammalian cells. Here we characterized TibA and showed that it possesses self-association characteristics and can mediate autoaggregation of E. coli cells. We demonstrated that intercellular TibA-TibA interaction is responsible for bacterial autoaggregation. Also, TibA expression significantly enhances biofilm formation by E. coli on abiotic surfaces.


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