scholarly journals Nanoscale Structural and Mechanical Properties of Nontypeable Haemophilus influenzae Biofilms

2009 ◽  
Vol 191 (8) ◽  
pp. 2512-2520 ◽  
Author(s):  
Fernando Terán Arce ◽  
Ross Carlson ◽  
James Monds ◽  
Richard Veeh ◽  
Fen Z. Hu ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Single Molecule ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Single Cells ◽  
Turgor Pressure ◽  
Outer Cell ◽  
Nontypeable Haemophilus Influenzae ◽  
Chronic Infections ◽  
Pathogenic Factors

ABSTRACT Nontypeable Haemophilus influenzae (NTHI) bacteria are commensals in the human nasopharynx, as well as pathogens associated with a spectrum of acute and chronic infections. Two important factors that influence NTHI pathogenicity are their ability to adhere to human tissue and their ability to form biofilms. Extracellular polymeric substances (EPS) and bacterial appendages such as pili critically influence cell adhesion and intercellular cohesion during biofilm formation. Structural components in the outer cell membrane, such as lipopolysaccharides, also play a fundamental role in infection of the host organism. In spite of their importance, these pathogenic factors are not yet well characterized at the nanoscale. Here, atomic force microscopy (AFM) was used in aqueous environments to visualize structural details, including probable Hif-type pili, of live NTHI bacteria at the early stages of biofilm formation. Using single-molecule AFM-based spectroscopy, the molecular elasticities of lipooligosaccharides present on NTHI cell surfaces were analyzed and compared between two strains (PittEE and PittGG) with very different pathogenicity profiles. Furthermore, the stiffness of single cells of both strains was measured and subsequently their turgor pressure was estimated.

scholarly journals Role of Sialic Acid and Complex Carbohydrate Biosynthesis in Biofilm Formation by Nontypeable Haemophilus influenzae in the Chinchilla Middle Ear

2005 ◽  
Vol 73 (6) ◽  
pp. 3210-3218 ◽  
Author(s):  
Joseph Jurcisek ◽  
Laura Greiner ◽  
Hiroshi Watanabe ◽  
Anthony Zaleski ◽  
Michael A. Apicella ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Haemophilus Influenzae ◽  
Middle Ear ◽  
Biofilm Formation ◽  
Mammalian Host ◽  
Nontypeable Haemophilus Influenzae ◽  
Biofilm Production ◽  
Tract Infections

ABSTRACT Nontypeable Haemophilus influenzae (NTHI) is an important pathogen in respiratory tract infections, including otitis media (OM). NTHI forms biofilms in vitro as well as in the chinchilla middle ear, suggesting that biofilm formation in vivo might play an important role in the pathogenesis and chronicity of OM. We've previously shown that SiaA, SiaB, and WecA are involved in biofilm production by NTHI in vitro. To investigate whether these gene products were also involved in biofilm production in vivo, NTHI strain 2019 and five isogenic mutants with deletions in genes involved in carbohydrate biosynthesis were inoculated into the middle ears of chinchillas. The wild-type strain formed a large, well-organized, and viable biofilm; however, the wecA, lsgB, siaA, pgm, and siaB mutants were either unable to form biofilms or formed biofilms of markedly reduced mass, organization, and viability. Despite their compromised ability to form a biofilm in vivo, wecA, lsgB, and siaA mutants survived in the chinchilla, inducing culture-positive middle ear effusions, whereas pgm and siaB mutants were extremely sensitive to the bactericidal activity of chinchilla serum and thus did not survive. Lectin analysis indicated that sialic acid was an important component of the NTHI 2019 biofilm produced in vivo. Our data suggested that genes involved in carbohydrate biosynthesis and assembly play an important role in the ability of NTHI to form a biofilm in vivo. Collectively, we found that when modeled in a mammalian host, whereas biofilm formation was not essential for survivability of NTHI in vivo, lipooligosaccharide sialylation was indispensable.

Helicobacter pylori Biofilm and New Strategies to Combat it

2020 ◽  
Vol 20 ◽  
Author(s):  
Majid Taati Moghadam ◽  
Zahra Chegini ◽  
Amin Khoshbayan ◽  
Iman Farahani ◽  
Aref Shariati
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Combination Therapies ◽  
Chronic Infections ◽  
Chemical Substances ◽  
And Performance ◽  
H Pylori ◽  
Initial Binding ◽  
New Strategies

: Helicobacter pylori, the most frequent pathogens worldwide that colonize around 50% of the world’s population, cause important diseases such as gastric adenocarcinoma, chronic gastritis, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In recent years, various studies have reported that H. pylori biofilm may be one of the critical barriers to the eradication of this bacterial infection. Biofilms inhibit the penetration of antibiotics, increase the expression of efflux pumps and mutations, multiple therapeutic failures, and chronic infections. Nanoparticles and natural products can demolish H. pylori biofilm by destroying the outer layers and inhibiting the initial binding of bacteria. Also, the use of combination therapies destroying extracellular polymeric substances decreases coccoid forms of bacteria and degrading polysaccharides in the outer matrix that lead to an increase in the permeability and performance of antibiotics. Different probiotics, antimicrobial peptides, chemical substances, and polysaccharides by inhibiting adhesion and colonization of H. pylori can prevent biofilm formation by this bacterium. Of note, many of the above are applicable to acidic pH and can be used to treat gastritis. Therefore, H. pylori biofilm may be one of the major causes of failure to the eradication of infections caused by this bacterium, and antibiotics are not capable of destroying the biofilm. Thus, it is necessary to use new strategies to prevent recurrent and chronic infections by inhibiting biofilm formation.

scholarly journals The Role of Bacterial Biofilm in Antibiotic Resistance and Food Contamination

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Gedif Meseret Abebe
Keyword(s):  
Antibiotic Resistance ◽  
Food Processing ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Food Contamination ◽  
Bacterial Biofilm ◽  
Natural Environments ◽  
Chronic Infections ◽  
Related Factors

Biofilm is a microbial association or community attached to different biotic or abiotic surfaces or environments. These surface-attached microbial communities can be found in food, medical, industrial, and natural environments. Biofilm is a critical problem in the medical sector since it is formed on medical implants within human tissue and involved in a multitude of serious chronic infections. Food and food processing surface become an ideal environment for biofilm formation where there are sufficient nutrients for microbial growth and attachment. Therefore, biofilm formation on these surfaces, especially on food processing surface becomes a challenge in food safety and human health. Microorganisms within a biofilm are encased within a matrix of extracellular polymeric substances that can act as a barrier and recalcitrant for different hostile conditions such as sanitizers, antibiotics, and other hygienic conditions. Generally, they persist and exist in food processing environments where they become a source of cross-contamination and foodborne diseases. The other critical issue with biofilm formation is their antibiotic resistance which makes medication difficult, and they use different physical, physiological, and gene-related factors to develop their resistance mechanisms. In order to mitigate their production and develop controlling methods, it is better to understand growth requirements and mechanisms. Therefore, the aim of this review article is to provide an overview of the role of bacterial biofilms in antibiotic resistance and food contamination and emphasizes ways for controlling its production.

scholarly journals Biofilms deform soft surfaces and disrupt epithelia

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Alice Cont ◽  
Tamara Rossy ◽  
Zainebe Al-Mayyah ◽  
Alexandre Persat
Keyword(s):  
Mechanical Stress ◽  
Biofilm Formation ◽  
Large Deformations ◽  
Single Cells ◽  
Chronic Infections ◽  
Common Assumption ◽  
Cell Monolayers ◽  
Mechanical Measurements ◽  
Internal Mechanical Stress ◽  
Epithelial Cell Monolayers

During chronic infections and in microbiota, bacteria predominantly colonize their hosts as multicellular structures called biofilms. A common assumption is that biofilms exclusively interact with their hosts biochemically. However, the contributions of mechanics, while being central to the process of biofilm formation, have been overlooked as a factor influencing host physiology. Specifically, how biofilms form on soft, tissue-like materials remains unknown. Here, we show that biofilms of the pathogens Vibrio cholerae and Pseudomonas aeruginosa can induce large deformations of soft synthetic hydrogels. Biofilms buildup internal mechanical stress as single cells grow within the elastic matrix. By combining mechanical measurements and mutations in matrix components, we found that biofilms deform by buckling, and that adhesion transmits these forces to their substrates. Finally, we demonstrate that V. cholerae biofilms can generate sufficient mechanical stress to deform and even disrupt soft epithelial cell monolayers, suggesting a mechanical mode of infection.

scholarly journals Subinhibitory Concentrations of Azithromycin Decrease Nontypeable Haemophilus influenzae Biofilm Formation and Diminish Established Biofilms

2007 ◽  
Vol 52 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Timothy D. Starner ◽  
Joshua D. Shrout ◽  
Matthew R. Parsek ◽  
Peter C. Appelbaum ◽  
GunHee Kim
Keyword(s):  
Haemophilus Influenzae ◽  
Biofilm Formation ◽  
Fluorescent Protein ◽  
Flow Cell ◽  
Nontypeable Haemophilus Influenzae ◽  
Chronic Lung Diseases ◽  
Airway Infections ◽  
Subinhibitory Concentrations ◽  
Green Fluorescent

ABSTRACT Nontypeable Haemophilus influenzae (NTHi) commonly causes otitis media, chronic bronchitis in emphysema, and early airway infections in cystic fibrosis. Long-term, low-dose azithromycin has been shown to improve clinical outcomes in chronic lung diseases, although the mechanism of action remains unclear. The inhibition of bacterial biofilms by azithromycin has been postulated to be one mechanism mediating these effects. We hypothesized that subinhibitory concentrations of azithromycin would affect NTHi biofilm formation. Laboratory strains of NTHi expressing green fluorescent protein and azithromycin-resistant clinical isolates were grown in flow-cell and static-culture biofilm models. Using a range of concentrations of azithromycin and gentamicin, we measured the degree to which these antibiotics inhibited biofilm formation and persistence. Large biofilms formed over 2 to 4 days in a flow cell, displaying complex structures, including towers and channels. Subinhibitory concentrations of azithromycin significantly decreased biomass and maximal thickness in both forming and established NTHi biofilms. In contrast, subinhibitory concentrations of gentamicin had no effect on biofilm formation. Furthermore, established NTHi biofilms became resistant to gentamicin at concentrations far above the MIC. Biofilm formation of highly resistant clinical NTHi isolates (azithromycin MIC of >64 μg/ml) was similarly decreased at subinhibitory azithromycin concentrations. Clinically obtainable azithromycin concentrations inhibited biofilms in all but the most highly resistant isolates. These data show that subinhibitory concentrations of azithromycin have antibiofilm properties, provide mechanistic insights, and supply an additional rationale for the use of azithromycin in chronic biofilm infections involving H. influenzae.

scholarly journals Reliability of Haemophilus influenzae biofilm measurement via static method, and determinants of in vitro biofilm production

2016 ◽  
Vol 62 (12) ◽  
pp. 1013-1020
Author(s):  
Najla A. Obaid ◽  
Stephen Tristram ◽  
Christian K. Narkowicz ◽  
Glenn A. Jacobson
Keyword(s):  
Haemophilus Influenzae ◽  
Biofilm Formation ◽  
Frozen Storage ◽  
Major Effect ◽  
Nontypeable Haemophilus Influenzae ◽  
Microtitre Plate ◽  
Biofilm Production ◽  
Solid Media ◽  
Inoculum Preparation

Information is lacking regarding the precision of microtitre plate (MTP) assays used to measure biofilm. This study investigated the precision of an MTP assay to measure biofilm production by nontypeable Haemophilus influenzae (NTHi) and the effects of frozen storage and inoculation technique on biofilm production. The density of bacterial final growth was determined by absorbance after 18–20 h incubation, and biofilm production was then measured by absorbance after crystal violet staining. Biofilm formation was categorised as high and low for each strain. For the high biofilm producing strains of NTHi, interday reproducibility of NTHi biofilm formation measured using the MTP assay was excellent and met the acceptance criteria, but higher variability was observed in low biofilm producers. Method of inoculum preparation was a determinant of biofilm formation with inoculum prepared directly from solid media showing increased biofilm production for at least one of the high producing strains. In general, storage of NTHi cultures at –80 °C for up to 48 weeks did not have any major effect on their ability to produce biofilm.

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

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