scholarly journals Lectins ofMycobacterium tuberculosis– rarely studied proteins

2019 ◽  
Vol 15 ◽  
pp. 1-15 ◽  
Author(s):  
Katharina Kolbe ◽  
Sri Kumar Veleti ◽  
Norbert Reiling ◽  
Thisbe K Lindhorst
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Biofilm Formation ◽  
Carbohydrate Binding ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Binding Characteristics ◽  
Ofmycobacterium Tuberculosis ◽  
Bacterial Lectins

The importance of bacterial lectins for adhesion, pathogenicity, and biofilm formation is well established for many Gram-positive and Gram-negative bacteria. However, there is very little information available about lectins of the tuberculosis-causing bacterium,Mycobacterium tuberculosis(Mtb). In this paper we review previous studies on the carbohydrate-binding characteristics of mycobacteria and relatedMtbproteins, discussing their potential relevance toMtbinfection and pathogenesis.

scholarly journals Amphipathic guanidine-embedded glyoxamide-based peptidomimetics as novel antibacterial agents and biofilm disruptors

2017 ◽  
Vol 15 (9) ◽  
pp. 2033-2051 ◽  
Author(s):  
Shashidhar Nizalapur ◽  
Onder Kimyon ◽  
Eugene Yee ◽  
Kitty Ho ◽  
Thomas Berry ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Antibacterial Agents ◽  
Gram Negative Bacteria ◽  
Planktonic Cells ◽  
Gram Positive ◽  
Gram Negative

Novel antibacterial peptidomimetics that inhibit the growth of planktonic cells and reduce biofilm formation in both Gram-positive and Gram-negative bacteria.

γ-Alkylidene-γ-lactones and isobutylpyrrol-2(5 H )-ones analogues to rubrolides as inhibitors of biofilm formation by Gram-positive and Gram-negative bacteria

2014 ◽  
Vol 24 (4) ◽  
pp. 1052-1056 ◽  
Author(s):  
Ulisses A. Pereira ◽  
Luiz C.A. Barbosa ◽  
Célia R.A. Maltha ◽  
Antônio J. Demuner ◽  
Mohammed A. Masood ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Bioinspired passive anti-biofouling surfaces preventing biofilm formation

2015 ◽  
Vol 3 (7) ◽  
pp. 1371-1378 ◽  
Author(s):  
Sasha Pechook ◽  
Kobi Sudakov ◽  
Iryna Polishchuk ◽  
Ievgeniia Ostrov ◽  
Varda Zakin ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Superhydrophobic Surfaces ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Our bioinspired, superhydrophobic surfaces show exceptional ability to passively inhibit the biofilm formation of Gram-positive and Gram-negative bacteria over a 7 day period.

scholarly journals Synthetic anti‐endotoxin peptides interfere with Gram‐positive and Gram‐negative bacteria, their adhesion and biofilm formation on titanium

2020 ◽  
Vol 129 (5) ◽  
pp. 1272-1286 ◽  
Author(s):  
L. Subh ◽  
W. Correa ◽  
T.‐J. Pinkvos ◽  
P. Behrens ◽  
K. Brandenburg ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

scholarly journals Outer Membrane Disruption Overcomes Intrinsic, Acquired, and Spontaneous Antibiotic Resistance

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Craig R. MacNair ◽  
Eric D. Brown
Keyword(s):  
Antibiotic Resistance ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Antibiotic Use ◽  
Membrane Disruption ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Outer Membrane Permeability

ABSTRACT Disruption of the outer membrane (OM) barrier allows for the entry of otherwise inactive antimicrobials into Gram-negative pathogens. Numerous efforts to implement this approach have identified a large number of OM perturbants that sensitize Gram-negative bacteria to many clinically available Gram-positive active antibiotics. However, there is a dearth of investigation into the strengths and limitations of this therapeutic strategy, with an overwhelming focus on characterization of individual potentiator molecules. Herein, we look to explore the utility of exploiting OM perturbation to sensitize Gram-negative pathogens to otherwise inactive antimicrobials. We identify the ability of OM disruption to change the rules of Gram-negative entry, overcome preexisting and spontaneous resistance, and impact biofilm formation. Disruption of the OM expands the threshold of hydrophobicity compatible with Gram-negative activity to include hydrophobic molecules. We demonstrate that while resistance to Gram-positive active antibiotics is surprisingly common in Gram-negative pathogens, OM perturbation overcomes many antibiotic inactivation determinants. Further, we find that OM perturbation reduces the rate of spontaneous resistance to rifampicin and impairs biofilm formation. Together, these data suggest that OM disruption overcomes many of the traditional hurdles encountered during antibiotic treatment and is a high priority approach for further development. IMPORTANCE The spread of antibiotic resistance is an urgent threat to global health that necessitates new therapeutics. Treatments for Gram-negative pathogens are particularly challenging to identify due to the robust outer membrane permeability barrier in these organisms. Recent discovery efforts have attempted to overcome this hurdle by disrupting the outer membrane using chemical perturbants and have yielded several new peptides and small molecules that allow the entry of otherwise inactive antimicrobials. However, a comprehensive investigation into the strengths and limitations of outer membrane perturbants as antibiotic partners is currently lacking. Herein, we interrogate the interaction between outer membrane perturbation and several common impediments to effective antibiotic use. Interestingly, we discover that outer membrane disruption is able to overcome intrinsic, spontaneous, and acquired antibiotic resistance in Gram-negative bacteria, meriting increased attention toward this approach.

scholarly journals SPECIES COMPOSITION OF ASSOCIATIONS AND RELATIONSHIPS BETWEEN MICROORGANISMS ISOLATED FROM OSTEOMYELITIS FOCUS

2021 ◽  
Vol 29 (2) ◽  
pp. 183-190
Author(s):  
I.V. Shipitsyna ◽  
◽  
E.V. Osipova ◽  
A.A. Natalskiy ◽  
A.V. Pavlov ◽  
...  
Keyword(s):  
Species Composition ◽  
Biofilm Formation ◽  
Specific Weight ◽  
Moderate Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Film Forming

Objective. To determine the species composition of the associations isolated from osteomyelitis foci and to study the character of associate relationships based on the biofilm-forming ability data. Methods. The microbiological study included clinical isolates (n=184) obtained from associations (n=88) during primary inoculations from wounds and fistulas of patients (n= 88) with chronic osteomyelitis of long tubular bones. In order to obtain an associative biofilm in vitro, the cultures of competing bacterial strains were daily mixed in 1:1 ratio. The biofilms were grown on the surface of polystyrene plates with subsequent determination of the level of biofilm formation in 24 and 48 hours. Thecoefficient of relationship (CR) was calculated to evaluate the synergistic, neutral and antagonistic relationships between bacteria in the biofilms. Results. The associations of staphylococcus with gram-negative bacteria were most frequently recovered from osteomyelitis foci. On the 1st day of the experiment, 38,6 % of associations had a moderate biofilm-forming ability, and besides, associations of gram-positive + gram-negative bacteria were observed in 36,4%; 42,1% of associations had a low biofilm-forming ability; 19,3% - had a high biofilm-forming ability. After 48 hours the percentage of mild adhesive strains remained at the same level - 38,6%, as for the low adhesive ones it decreased to 36,4%, high adhesive - increased up to 25%. Most bacterial associations manifested antagonistic relationships. Synergism in biofilm-formingby the association of S. aureus + P. aeruginosa was observed in 2 cases,while the level of film-forming was high as on the first and the second day of the study. In several associations it transformed from antagonistic to synergistic or neutral relationships. Conclusion. It has ben established that among the identified associations, the largest specific weight falls on the associations of gram-positive + gram-negative bacteria , while S. aureus is one of the most common components. These associations were noted to have high and mild activity of biofilm -forming on the surface of polystyrene plates. Relationships between the microorganisms isolated from osteomyelitis foci in associations, as a rule, are antagonistic. What this paper adds For the first time, the nature of the relationship between microorganisms in the composition of associations isolated from the osteomyelitis focus has been studied on the basis of biofilm-forming ability data. It has been established that in microbiocenosis of the osteomyelitis foci, the greatest specific weight falls on the associations of S. aureus with gram-negative bacteria. These associations have a high and moderate activity of biofilm formation on the surface of polystyrene plates. The relationships between microorganisms isolated from the osteomyelitis focus as part of associations are usually antagonistic.

scholarly journals Identification of the Clostridial cellulose synthase and characterization of the cognate glycosyl hydrolase, CcsZ

2019 ◽  
Author(s):  
William Scott ◽  
Brian Lowrance ◽  
Alexander C. Anderson ◽  
Joel T. Weadge
Keyword(s):  
Biofilm Formation ◽  
Clostridium Botulinum ◽  
Molecular Mechanisms ◽  
Cellulose Synthase ◽  
Gram Negative Bacteria ◽  
Human Pathogens ◽  
Gram Positive ◽  
Gram Negative ◽  
Clostridioides Difficile ◽  
Spore Forming Bacteria

AbstractBiofilms are community structures of bacteria enmeshed in a self-produced matrix of exopolysaccharides. The biofilm matrix serves numerous roles, including resilience and persistence, making biofilms a subject of research interest among persistent clinical pathogens of global health importance. Our current understanding of the underlying biochemical pathways responsible for biosynthesis of these exopolysaccharides is largely limited to Gram-negative bacteria. Clostridia are a class of Gram-positive, anaerobic and spore-forming bacteria, and include the important human pathogens Clostridium perfringens, Clostridium botulinum, and Clostridioides difficile, among numerous others. Clostridia have been reported to form biofilms composed of cellulose, although the specific loci which encode the cellulose synthase have not been identified. Here, we report the discovery of a gene cluster, which we named ccsABZCD, among selected bacteria within class Clostridia that appears to encode a synthase complex responsible for polymerization, modification, and export of an O-acetylated cellulose exopolysaccharide. To test this hypothesis, we subcloned the putative glycoside hydrolase CcsZ and solved the X-ray crystal structure of both apo- and product-bound CcsZ. Our results demonstrate that CcsZ is in fact an endo-acting cellulase belonging to glycoside hydrolase family 5 (GH-5). This is in contrast to the Gram-negative cellulose synthase, which instead encodes BcsZ, a structurally distinct GH-8. We further show CcsZ is capable of hydrolysis of the soluble mock substrate carboxymethylcellulose (CMC) with a pH optimum of 4.5. The data we present here serves as an entry point to an understanding of biofilm formation among class Clostridia and allowed us to predict a model for Clostridial cellulose synthesis.Author summaryBiofilms are communities of microorganisms that enmesh themselves in a protective matrix of elf-produced polysaccharide materials. Biofilms have demonstrated roles in both virulence and persistence among bacterial pathogens of global health importance. The class Clostridia are a polyphyletic grouping of primarily Gram-positive, anaerobic and spore-forming bacteria which contain the important and well-studied human pathogens Clostridioides difficile, Clostridium botulinum, and Clostridium perfringens, among others. Bacteria belonging to class Clostridia have been anecdotally reported to form biofilms made of cellulose, although the molecular mechanisms governing their production has not before been described. In this work, we identify a gene cluster, which we name ccsABZHI, for the Clostridial cellulose synthase, which bears remarkable similarity to molecular machinery required for the production of cellulose biofilms in other Gram-negative bacteria. We further biochemically characterize one of these enzymes, CcsZ, a predicted endoglucanase which we predicted from our model should cleave cellulose exopolysaccharides. We show that CcsZ is in fact capable of this activity and belongs to a broader family of glycoside hydrolases with unexpected taxonomic diversity. Our work represents an entry point towards an understanding of the molecular mechanisms governing cellulose biofilm formation in Gram-positive bacteria.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

In-vitro Antioxidant and Antibacterial Activity of Methanolic Extract of Shorea robusta Gaertn. F. Resin

2016 ◽  
Vol 6 (4) ◽  
pp. 68
Author(s):  
Sushma Vashisht ◽  
Manish Pal Singh ◽  
Viney Chawla
Keyword(s):  
Antibacterial Activity ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Positive ◽  
Gram Negative ◽  
Shorea Robusta ◽  
Dose Dependent ◽  
Resin Extract

The methanolic extract of the resin of Shorea robusta was subjected to investigate its antioxidant and antibacterial properties its utility in free radical mediated diseases including diabetic, cardiovascular, cancer etc. The methanol extract of the resin was tested for antioxidant activity using scavenging activity of DPPH (1,1-diphenyl-2-picrylhydrazil) radical method, reducing power by FeCl3 and antibacterial activity against gram positive and gram negative bacteria using disc diffusion method. The phytochemical screening considered the presence of triterpenoids, tannins and flavoniods. Overall, the plant extract is a source of natural antioxidants which might be helpful in preventing the progress of various oxidative stress mediated diseases including aging. The half inhibition concentration (IC50) of resin extract of Shorea robusta and ascorbic acid were 35.60 µg/ml and 31.91 µg/ml respectively. The resin extract exhibit a significant dose dependent inhibition of DPPH activity. Antibacterial activity was observed against gram positive and gram negative bacteria in dose dependent manner.Key Words: Shorea robusta, antioxidant, antibacterial, Disc-diffusion, DPPH.

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