Surface Glucan Structures in Aeromonas spp.

Aeromonas spp. are generally found in aquatic environments, although they have also been isolated from both fresh and processed food. These Gram-negative, rod-shaped bacteria are mostly infective to poikilothermic animals, although they are also considered opportunistic pathogens of both aquatic and terrestrial homeotherms, and some species have been associated with gastrointestinal and extraintestinal septicemic infections in humans. Among the different pathogenic factors associated with virulence, several cell-surface glucans have been shown to contribute to colonization and survival of Aeromonas pathogenic strains, in different hosts. Lipopolysaccharide (LPS), capsule and α-glucan structures, for instance, have been shown to play important roles in bacterial–host interactions related to pathogenesis, such as adherence, biofilm formation, or immune evasion. In addition, glycosylation of both polar and lateral flagella has been shown to be mandatory for flagella production and motility in different Aeromonas strains, and has also been associated with increased bacterial adhesion, biofilm formation, and induction of the host proinflammatory response. The main aspects of these structures are covered in this review.

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The Use of Zwitterionic Methylmethacrylat Coated Silicone Inhibits Bacterial Adhesion and Biofilm Formation of Staphylococcus aureus

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.686192 ◽

2021 ◽

Vol 9 ◽

Author(s):

Franziska Woitschach ◽

Marlen Kloss ◽

Karsten Schlodder ◽

Anne Rabes ◽

Caroline Mörke ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Bacterial Colonization ◽

Thermoplastic Polyurethane ◽

Opportunistic Pathogens ◽

Bacterial Strains ◽

Liquid Silicone Rubber ◽

Liquid Silicone ◽

Biofilm Bacteria

In recent decades, biofilm-associated infections have become a major problem in many medical fields, leading to a high burden on patients and enormous costs for the healthcare system. Microbial infestations are caused by opportunistic pathogens which often enter the incision already during implantation. In the subsequently formed biofilm bacteria are protected from the hosts immune system and antibiotic action. Therefore, the development of modified, anti-microbial implant materials displays an indispensable task. Thermoplastic polyurethane (TPU) represents the state-of-the-art material in implant manufacturing. Due to the constantly growing areas of application and the associated necessary adjustments, the optimization of these materials is essential. In the present study, modified liquid silicone rubber (LSR) surfaces were compared with two of the most commonly used TPUs in terms of bacterial colonization and biofilm formation. The tests were conducted with the clinically relevant bacterial strains Staphylococcus aureus and Staphylococcus epidermidis. Crystal violet staining and scanning electron microscopy showed reduced adhesion of bacteria and thus biofilm formation on these new materials, suggesting that the investigated materials are promising candidates for implant manufacturing.

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Large Scale Discovery of Microbial Fibrillar Adhesins and Identification of Novel Adhesive Domain Families

10.1101/2021.12.07.471604 ◽

2021 ◽

Author(s):

Vivian Angela Monzon ◽

Alex Bateman

Keyword(s):

Biofilm Formation ◽

Large Scale ◽

Significant Contribution ◽

Structural Similarity ◽

Surface Proteins ◽

Host Cells ◽

Bacterial Host ◽

Cell Surface Proteins ◽

Host Interactions ◽

Prediction Approach

Fibrillar adhesins are bacterial cell surface proteins that mediate interactions with host cells during colonisation and with other bacteria during biofilm formation. These proteins are characterised by a stalk that projects the adhesive domain closer to the binding target. Fibrillar adhesins evolve quickly and thus can be difficult to computationally identify, yet they represent an important component for understanding bacterial host interactions. To detect novel fibrillar adhesins we developed a random forest prediction approach based on common characteristics we identified for this protein class. We applied this approach to Firmicute and Actinobacterial proteomes, yielding over 4,000 confidently predicted fibrillar adhesins. To verify the approach we investigated predicted fibrillar adhesins that lacked a known adhesive domain. Based on these proteins, we identified 21 sequence clusters representing potential novel adhesive domains. We used AlphaFold to verify that 14 clusters showed structural similarity to known adhesive domains such as the TED domain. Overall our study has made a significant contribution to the number of known fibrillar adhesins and has enabled us to identify novel adhesive domain families involved in the bacterial pathogenesis.

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Confocal and SEM imaging to demonstrate food pathogen- biofilm biocontrol by pyocyanin from Pseudomonas aeruginosa BTRY1

International Journal of Bioassays ◽

10.21746/ijbio.2017.01.007 ◽

2016 ◽

Vol 6 (01) ◽

pp. 5218

Author(s):

Laxmi Mohandas ◽

Anju T. R. ◽

Sarita G. Bhat*

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Antibiofilm Activity ◽

Opportunistic Pathogens ◽

Redox Active ◽

Sem Imaging ◽

The Impact

An assortment of redox-active phenazine compounds like pyocyanin with their characteristic blue-green colour are synthesized by Pseudomonas aeruginosa, Gram-negative opportunistic pathogens, which are also considered one of the most commercially valuable microorganisms. In this study, pyocyanin from Pseudomonas aeruginosa BTRY1 from food sample was assessed for its antibiofilm activity by micro titer plate assay against strong biofilm producers belonging to the genera Bacillus, Staphylococcus, Brevibacterium and Micrococcus. Pyocyanin inhibited biofilm activity in very minute concentrations. This was also confirmed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Both SEM and CLSM helped to visualize the biocontrol of biofilm formation by eight pathogens. The imaging and quantification by CLSM also established the impact of pyocyanin on biofilm-biocontrol mainly in the food industry.

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Bond Strengthening in Oral Bacterial Adhesion to Salivary Conditioning Films

Applied and Environmental Microbiology ◽

10.1128/aem.01119-08 ◽

2008 ◽

Vol 74 (17) ◽

pp. 5511-5515 ◽

Cited By ~ 40

Author(s):

Henny C. van der Mei ◽

Minie Rustema-Abbing ◽

Joop de Vries ◽

Henk J. Busscher

Keyword(s):

Bacterial Adhesion ◽

Biofilm Formation ◽

Specific Interactions ◽

Adhesion Forces ◽

Bacterial Strains ◽

Bacterial Interactions ◽

Initial Adhesion ◽

Conditioning Film ◽

Interacting Surfaces ◽

Conditioning Films

ABSTRACT Transition from reversible to irreversible bacterial adhesion is a highly relevant but poorly understood step in initial biofilm formation. We hypothesize that in oral biofilm formation, irreversible adhesion is caused by bond strengthening due to specific bacterial interactions with salivary conditioning films. Here, we compared the initial adhesion of six oral bacterial strains to salivary conditioning films with their adhesion to a bovine serum albumin (BSA) coating and related their adhesion to the strengthening of the binding forces measured with bacteria-coated atomic force microscopy cantilevers. All strains adhered in higher numbers to salivary conditioning films than to BSA coatings, and specific bacterial interactions with salivary conditioning films were accompanied by stronger initial adhesion forces. Bond strengthening occurred on a time scale of several tens of seconds and was slower for actinomyces than for streptococci. Nonspecific interactions between bacteria and BSA coatings strengthened twofold faster than their specific interactions with salivary conditioning films, likely because specific interactions require a closer approach of interacting surfaces with the removal of interfacial water and a more extensive rearrangement of surface structures. After bond strengthening, bacterial adhesion forces with a salivary conditioning film remained stronger than those with BSA coatings.

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A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation

Sensors ◽

10.3390/s21082771 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2771

Author(s):

Tobias Wieland ◽

Julia Assmann ◽

Astrid Bethe ◽

Christian Fidelak ◽

Helena Gmoser ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Real Time ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Pathogenic Bacteria ◽

Bovine Mastitis ◽

Inhibitory Effect ◽

Thermal Sensor ◽

Bacterial Cells ◽

Static Conditions

The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.

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Immunopathological mechanisms in bacterial-host interactions

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1983.0091 ◽

1983 ◽

Vol 303 (1114) ◽

pp. 177-187 ◽

Cited By ~ 6

Keyword(s):

Rheumatic Fever ◽

Group A Streptococcus ◽

Biological Properties ◽

Antigenic Determinants ◽

Bacterial Host ◽

Poststreptococcal Glomerulonephritis ◽

Host Interactions ◽

Disease States ◽

Group A ◽

Specific Tissue

The ability of bacteria to cause immunopathological damage in the host may take a variety of forms. These pathways may be conveniently grouped under three major headings: (1) organisms that can cause damage via shared antigenic determinants between host and bacterium; (2) those organisms that suppress the host’s response; and (3) organisms that release substances with specific biological properties or have receptors for specific tissue sites. The group A streptococcus is among the most versatile of these bacteria because it appears that it may use all three pathways in various streptococcal-related disease states. In rheumatic fever and chorea it appears that cross-reactive antigens play a major role in inducing immunopathological damage in that there is both a heightened humoral and cellular reaction by the host to these cross-reactive determinants. Recent evidence also indicates that rheumatic fever individuals express certain B cell antigens that may be associated with susceptibility to the disease. In the other complications of streptococcal infections, namely poststreptococcal glomerulonephritis, the bacterium uses both suppression of the host’s immune response and the excretion of a particular protein common to all nephritis-associated strains to achieve its immunopathological damage. In this context, other examples of bacterial-host interactions will be discussed as evidence for the common pathways used by microbes to cause immunopathological damage in the host.

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Sampling bias created by ampicillin in isolation media forAeromonas

Canadian Journal of Microbiology ◽

10.1139/w06-103 ◽

2007 ◽

Vol 53 (1) ◽

pp. 39-44 ◽

Cited By ~ 7

Author(s):

Jennifer R Huddleston ◽

John C Zak ◽

Randall M Jeter

Keyword(s):

Sampling Bias ◽

Aeromonas Species ◽

Aquatic Environments ◽

Selective Agent ◽

Opportunistic Pathogens ◽

Chi Square ◽

Isolation Medium ◽

Ability To Act ◽

Chi Square Analysis ◽

The Impact

Members of the bacterial genus Aeromonas are widely isolated from aquatic environments and studied in part for their ability to act as opportunistic pathogens in a variety of animals. All aeromonads, with the exception of Aeromonas trota, are generally thought to be resistant to ampicillin, so the antibiotic is frequently added to isolation medium as a selective agent. In this study, 282 aeromonads from environmental sources were isolated on a medium without ampicillin and their resistance to ampicillin determined. Of the 104 of these isolates that were judged to be independent (nonredundant), 18 (17.3%) were susceptible to ampicillin. A chi-square analysis was performed to determine the impact of ampicillin use on enumerating Aeromonas species from environmental samples. Our results indicate that, when ampicillin is used as a selective agent, a significant portion of the aeromonad population in at least some environ ments can be omitted from isolation.Key words: Aeromonas, ampicillin, selective media.

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Bacterial adhesion to collagens: implications for biofilm formation and disease progression in the oral cavity

Critical Reviews in Microbiology ◽

10.1080/1040841x.2021.1944054 ◽

2021 ◽

pp. 1-13

Author(s):

Simón Álvarez ◽

Camila Leiva-Sabadini ◽

Christina M. A. P. Schuh ◽

Sebastian Aguayo

Keyword(s):

Oral Cavity ◽

Disease Progression ◽

Bacterial Adhesion ◽

Biofilm Formation

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Monolithic Ceramics: Effect of Finishing Techniques on Surface Properties, Bacterial Adhesion and Cell Viability

Operative Dentistry ◽

10.2341/17-011-l ◽

2018 ◽

Vol 43 (3) ◽

pp. 315-325 ◽

Cited By ~ 20

Author(s):

AMO Dal Piva ◽

LPC Contreras ◽

FC Ribeiro ◽

LC Anami ◽

SEA Camargo ◽

...

Keyword(s):

Mtt Assay ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Nonparametric Tests ◽

Lithium Silicate ◽

Gingival Fibroblasts ◽

Sem Images ◽

High Profile ◽

Colony Forming Units ◽

Monolithic Ceramics

SUMMARY Introduction: This study evaluated the morphology, biofilm formation, and viability of human gingival fibroblasts in contact with two monolithic ceramics after two different finishing techniques: polishing or glazing. For this, 92 blocks (4.5 × 4.5 × 1.5 mm) of each ceramic were made using high translucency zirconia partially stabilized by yttrium (YZHT) and lithium silicate reinforced by zirconium (ZLS). Methods and Materials: Blocks were sintered and then divided into glazing (g) or polishing (p) surface finish. Surface roughness (Ra and RSm) was evaluated through a contact rugosimeter and profilometry. Specimens were contaminated for heterotypic biofilm formation with Streptococcus mutans, Streptococcus sanguinis and Candida albicans for 16 hours. Biofilm was quantified by counting the colony forming units (CFU/mL) and analyzed by scanning electron microscopy (SEM). Fibroblast viability was evaluated by MTT assay. Surface free energy (SFE) was also determined. Roughness data were evaluated using nonparametric tests, while SFE, MTT and CFU results were evaluated by analysis of variance and Tukey test, and MTT data were also submitted to t-test (all, α=0.05). Results: Results showed that polished samples presented a lower high profile mean (p<0.001); however, YZHTg presented less space between defects (p=0.0002). SFE showed that YZHT presented higher SFE than ZLS. Profilometry evidenced more homogeneity on polished surfaces. The interaction of finishing technique and microorganisms influenced the CFU (p=0.00). MTT assay demonstrated initial severe cytotoxic behavior for polished surfaces. SEM images showed homogeneous surfaces, except for glazed YZHT. Conclusion: Glazed surfaces have a greater roughness and tend to accumulate more biofilm. Polished surfaces have higher SFE; however, they are temporarily cytotoxic.

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