scholarly journals Sinefungin, a Natural Nucleoside Analogue of S-Adenosylmethionine, InhibitsStreptococcus pneumoniaeBiofilm Growth

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mukesh Kumar Yadav ◽  
Seok-Won Park ◽  
Sung-Won Chae ◽  
Jae-Jun Song
Keyword(s):  
Nucleoside Analogue ◽  
Biofilm Formation ◽  
Gene Expressions ◽  
Biofilm Growth ◽  
Autoinducer 2 ◽  
The Matrix ◽  
Pneumococcal Colonization ◽  
Antibiofilm Agents

Pneumococcal colonization and disease is often associated with biofilm formation, in which the bacteria exhibit elevated resistance both to antibiotics and to host defense systems, often resulting in infections that are persistent and difficult to treat. We evaluated the effect of sinefungin, a nucleoside analogue of S-adenosylmethionine, on pneumococcalin vitrobiofilm formation andin vivocolonization. Sinefungin is bacteriostatic to pneumococci and significantly decreased biofilm growth and inhibited proliferation and structure of actively growing biofilms but did not alter growth or the matrix structure of established biofilms. Sinefungin significantly reduced pneumococcal colonization in rat middle ear. The quorum sensing molecule (autoinducer-2) production was significantly reduced by 92% in sinefungin treated samples. TheluxS, pfs, andspeEgenes were downregulated in biofilms grown in the presence of sinefungin. This study shows that sinefungin inhibits pneumococcal biofilm growthin vitroand colonizationin vivo, decreases AI-2 production, and downregulatesluxS,pfs, andspeEgene expressions. Therefore, the S-adenosylmethionine (SAM) inhibitors could be used as lead compounds for the development of novel antibiofilm agents against pneumococci.

Biosurfactants of Lactobacillus helveticus for biodiversity inhibit the biofilm formation of Staphylococcus aureus and cell invasion

2019 ◽  
Vol 14 (13) ◽  
pp. 1133-1146 ◽  
Author(s):  
Xinpeng Jiang ◽  
Xin Yan ◽  
Shanshan Gu ◽  
Yan Yang ◽  
Lili Zhao ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Biofilm Formation ◽  
Lactobacillus Helveticus ◽  
Real Time Quantitative Pcr ◽  
Autoinducer 2 ◽  
New Strategy ◽  
Better Than

Aim: This study aimed to evaluate the differences of biosurfactants produced by two Lactobacillus helveticus strains against the biofilm formation of Staphylococcus aureus in vitro and in vivo. Materials & methods: Scanning electron microscopy, Real time-quantitative PCR (RT-qPCR) and cell assay were used to analyze the inhibiting effect of biosurfactants against biofilm formation. Results & conclusion: Results showed that the biosurfactants have anti-adhesive and inhibiting effects on biofilm formation in vivo and in vitro. The biofilm-formative genes and autoinducer-2 signaling regulated these characteristics, and the biosurfactant L. helveticus 27170 is better than that of 27058. Host cell adhesion and invasion results indicated that the biosurfactants L. helveticus prevented the S. aureus invading the host cell, which may be a new strategy to eliminate biofilms.

scholarly journals Effect of host-mimicking medium and biofilm growth on the ability of colistin to kill Pseudomonas aeruginosa

Microbiology ◽  
2020 ◽  
Vol 166 (12) ◽  
pp. 1171-1180 ◽  
Author(s):  
Esther Sweeney ◽  
Akshay Sabnis ◽  
Andrew M. Edwards ◽  
Freya Harrison
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ex Vivo ◽  
Clinical Success ◽  
Biofilm Growth ◽  
Content Type ◽  
The Matrix ◽  
Model Versus ◽  
High Doses

In vivo biofilms cause recalcitrant infections with extensive and unpredictable antibiotic tolerance. Here, we demonstrate increased tolerance of colistin by Pseudomonas aeruginosa when grown in medium that mimics cystic fibrosis (CF) sputum versus standard medium in in vitro biofilm assays, and drastically increased tolerance when grown in an ex vivo CF model versus the in vitro assay. We used colistin conjugated to the fluorescent dye BODIPY to assess the penetration of the antibiotic into ex vivo biofilms and showed that poor penetration partly explains the high doses of drug necessary to kill bacteria in these biofilms. The ability of antibiotics to penetrate the biofilm matrix is key to their clinical success, but hard to measure. Our results demonstrate both the importance of reduced entry into the matrix in in vivo-like biofilm, and the tractability of using a fluorescent tag and benchtop fluorimeter to assess antibiotic entry into biofilms. This method could be a relatively quick, cheap and useful addition to diagnostic and drug development pipelines, allowing the assessment of drug entry into biofilms, in in vivo-like conditions, prior to more detailed tests of biofilm killing.

scholarly journals Effect of Simulated Gastrointestinal Conditions on Biofilm Formation bySalmonella1,4,[5],12:i:-

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
R. Seixas ◽  
M. Gabriel ◽  
J. Machado ◽  
L. Tavares ◽  
F. Bernardo ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Biofilm Formation ◽  
Contributing Factors ◽  
Biofilm Growth ◽  
Biofilm Production ◽  
Gastrointestinal Conditions ◽  
Mueller Hinton ◽  
Mueller Hinton Broth

SalmonellaTyphimurium 1,4,[5],12:i:- is a major serovar responsible for human salmonellosis whose biofilm-forming ability, influenced by environmental conditions like those found in the gastrointestinal tract, is one of the main contributing factors to its ability to persist in the host and thus one of the main causes of chronic relapsing infections. Most studies to evaluate biofilm formation are performed in microtiter assays using standard media. However, no reports are available on the ability of this serovar to produce biofilm underin vitrosimulated gastrointestinal conditions which better correlate with the environment found in the gastrointestinal tract. To address this, a modified biofilm assay simulating intestinal fluid was conceived to assess the biofilm formation of 133SalmonellaTyphimurium 1,4,[5],12:i:- isolates with and without agitation and at three different time points (24 h, 48 h, and 72 h). The results were then compared to the existing microtiter method using conventional biofilm growth medium (Mueller Hinton Broth). Statistical analysis revealed significant differences in the results obtained between the three protocols used. The simulated human intestinal environment impaired biofilm production demonstrating that conditions like pH, agitation or the presence of enzymes can influence biofilm production. Therefore, results fromin vitrosimulation ofin vivoconditions may contribute to unravelling factors relating to biofilm formation and persistence in the context of the human host.

scholarly journals Hyperencapsulated mucoid pneumococcal isolates from patients with cystic fibrosis have increased biofilm density and persistence in vivo

2018 ◽  
Vol 76 (7) ◽  
Author(s):  
Evida A Dennis ◽  
Mamie T Coats ◽  
Sarah Griffin ◽  
Bing Pang ◽  
David E Briles ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Continuous Flow ◽  
Biofilm Formation ◽  
Capsular Polysaccharides ◽  
Wild Type ◽  
Pneumococcal Colonization ◽  
Phase Variants

AbstractMucoid bacteria, predominately Pseudomonas aeruginosa, are commonly associated with decline in pulmonary function in children with cystic fibrosis (CF), and are thought to persist at least in part due to a greater propensity toward forming biofilms. We isolated a higher frequency of mucoid Streptococcus pneumoniae (Sp) expressing high levels of capsular polysaccharides from sputa from children with CF, compared to those without CF. We compared biofilm formation and maturation by mucoid and non-mucoid isolates of Sp collected from children with and without CF. Non-mucoid Sp serotype 19A and 19F isolates had significantly higher levels of biofilm initiation and adherence to CF epithelial cells than did serotype 3 isolates. However, strains expressing high levels of capsule had significantly greater biofilm maturation, as evidenced by increased density and thickness in static and continuous flow assays via confocal microscopy. Finally, using a serotype 3 Sp strain, we showed that highly encapsulated mucoid phase variants predominate during late adherence and better colonize CFTR–/– as compared to wild-type mice in respiratory infection studies. These findings indicate that overexpression of capsule can enhance the development of mature pneumococcal biofilms in vitro, and may contribute to pneumococcal colonization in CF lung disease.

scholarly journals High Levels of Genetic Recombination during Nasopharyngeal Carriage and Biofilm Formation in Streptococcus pneumoniae

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Laura R. Marks ◽  
Ryan M. Reddinger ◽  
Anders P. Hakansson
Keyword(s):  
Biofilm Formation ◽  
Transformation Efficiency ◽  
Genetic Exchange ◽  
Biofilm Growth ◽  
High Transformation ◽  
Lower Temperature ◽  
Multiple Strains

ABSTRACTTransformation of genetic material between bacteria was first observed in the 1920s usingStreptococcus pneumoniaeas a model organism. Since then, the mechanism of competence induction and transformation has been well characterized, mainly using planktonic bacteria or septic infection models. However, epidemiological evidence suggests that genetic exchange occurs primarily during pneumococcal nasopharyngeal carriage, which we have recently shown is associated with biofilm growth, and is associated with cocolonization with multiple strains. However, no studies to date have comprehensively investigated genetic exchange during cocolonizationin vitroandin vivoor the role of the nasopharyngeal environment in these processes. In this study, we show that genetic exchange during dual-strain carriagein vivois extremely efficient (10−2) and approximately 10,000,000-fold higher than that measured during septic infection (10−9). This high transformation efficiency was associated with environmental conditions exclusive to the nasopharynx, including the lower temperature of the nasopharynx (32 to 34°C), limited nutrient availability, and interactions with epithelial cells, which were modeled in a novel biofilm modelin vitrothat showed similarly high transformation efficiencies. The nasopharyngeal environmental factors, combined, were critical for biofilm formation and induced constitutive upregulation of competence genes and downregulation of capsule that promoted transformation. In addition, we show that dual-strain carriagein vivoand biofilms formedin vitrocan be transformed during colonization to increase their pneumococcal fitness and also, importantly, that bacteria with lower colonization ability can be protected by strains with higher colonization efficiency, a process unrelated to genetic exchange.IMPORTANCEAlthough genetic exchange between pneumococcal strains is known to occur primarily during colonization of the nasopharynx and colonization is associated with biofilm growth, this is the first study to comprehensively investigate transformation in this environment and to analyze the role of environmental and bacterial factors in this process. We show that transformation efficiency during cocolonization by multiple strains is very high (around 10−2). Furthermore, we provide novel evidence that specific aspects of the nasopharyngeal environment, including lower temperature, limited nutrient availability, and epithelial cell interaction, are critical for optimal biofilm formation and transformation efficiency and result in bacterial protein expression changes that promote transformation and fitness of colonization-deficient strains. The results suggest that cocolonization in biofilm communities may have important clinical consequences by facilitating the spread of antibiotic resistance and enabling serotype switching and vaccine escape as well as protecting and retaining poorly colonizing strains in the pneumococcal strain pool.

scholarly journals Assessment of Ceragenins in Prevention of Damage to Voice Prostheses Caused by Candida Biofilm Formation

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1371
Author(s):  
Jakub Spałek ◽  
Tamara Daniluk ◽  
Adrian Godlewski ◽  
Piotr Deptuła ◽  
Urszula Wnorowska ◽  
...  
Keyword(s):  
Candida Species ◽  
Biofilm Formation ◽  
Significant Proportion ◽  
Life Quality ◽  
Ethanol Solution ◽  
In Vivo Studies ◽  
Biofilm Growth ◽  
Voice Prostheses

This study aimed to investigate the potential application of ceragenins (CSAs) as new candidacidal agents to prevent biofilm formation on voice prostheses (VPs). The deterioration of the silicone material of VPs is caused by biofilm growth on the device which leads to frequent replacement procedures and sometimes serious complications. A significant proportion of these failures is caused by Candida species. We found that CSAs have significant candidacidal activities in vitro (MIC; MFC; MBIC), and they effectively eradicate species of yeast responsible for VP failure. Additionally, in our in vitro experimental setting, when different Candida species were subjected to CSA-13 and CSA-131 during 25 passages, no tested Candida strain showed the significant development of resistance. Using liquid chromatography–mass spectrometry (LC-MS), we found that VP immersion in an ethanol solution containing CSA-131 results in silicon impregnation with CSA-131 molecules, and in vitro testing revealed that fungal biofilm formation on such VP surfaces was inhibited by embedded ceragenins. Future in vivo studies will validate the use of ceragenin-coated VP for improvement in the life quality and safety of patients after a total laryngectomy.

scholarly journals Effect of host-mimicking medium and biofilm growth on the ability of colistin to kill Pseudomonas aeruginosa

2020 ◽  
Author(s):  
Esther Sweeney ◽  
Akshay Sabnis ◽  
Andrew M. Edwards ◽  
Freya Harrison
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ex Vivo ◽  
Clinical Success ◽  
Biofilm Growth ◽  
The Matrix ◽  
Model Versus ◽  
High Doses ◽  
Fluorescent Tag

AbstractIn vivo biofilms cause recalcitrant infections with extensive and unpredictable antibiotic tolerance. Here, we demonstrate increased tolerance of colistin by Pseudomonas aeruginosa when grown in cystic fibrosis-mimicking medium versus standard medium in in vitro biofilm assays, and drastically increased tolerance when grown in an ex vivo CF model versus the in vitro assay. We used colistin conjugated to the fluorescent dye BODIPY to assess the penetration of the antibiotic into ex vivo biofilms and showed that poor penetration partly explains the high doses of drug necessary to kill bacteria in these biofilms. The ability of antibiotics to penetrate the biofilm matrix is key to their clinical success, but hard to measure. Our results demonstrate both the importance of reduced entry into the matrix in in vivo-like biofilm, and the tractability of using a fluorescent tag and benchtop fluorimeter to assess antibiotic entry into biofilms. This method could be a relatively quick, cheap and useful addition to diagnostic and R&D pipelines, allowing the assessment of drug entry into biofilms, in in vivo-like conditions, prior to more detailed tests of biofilm killing.

scholarly journals Aminoglycoside inhibition of Staphylococcus aureus biofilm formation is nutrient dependent

2014 ◽  
Vol 63 (6) ◽  
pp. 861-869 ◽  
Author(s):  
Michelle J. Henry-Stanley ◽  
Donavon J. Hess ◽  
Carol L. Wells
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Growth Medium ◽  
Antibiotic Susceptibility ◽  
Biofilm Formation ◽  
Nutrient Concentration ◽  
Growth Media ◽  
Biofilm Growth

Biofilms represent microbial communities, encased in a self-produced matrix or extracellular polymeric substance. Microbial biofilms are likely responsible for a large proportion of clinically significant infections and the multicellular nature of biofilm existence has been repeatedly associated with antibiotic resistance. Classical in vitro antibiotic-susceptibility testing utilizes artificial growth media and planktonic microbes, but this method may not account for the variability inherent in environments subject to biofilm growth in vivo. Experiments were designed to test the hypothesis that nutrient concentration can modulate the antibiotic susceptibility of Staphylococcus aureus biofilms. Developing S. aureus biofilms initiated on surgical sutures, and in selected experiments planktonic cultures, were incubated for 16 h in 66 % tryptic soy broth, 0.2 % glucose (1× TSBg), supplemented with bactericidal concentrations of gentamicin, streptomycin, ampicillin or vancomycin. In parallel experiments, antibiotics were added to growth medium diluted one-third (1/3× TSBg) or concentrated threefold (3× TSBg). Following incubation, viable bacteria were enumerated from planktonic cultures or suture sonicates, and biofilm biomass was assayed using spectrophotometry. Interestingly, bactericidal concentrations of gentamicin (5 µg gentamicin ml−1) and streptomycin (32 µg streptomycin ml−1) inhibited biofilm formation in samples incubated in 1/3× or 1× TSBg, but not in samples incubated in 3× TSBg. The nutrient dependence of aminoglycoside susceptibility is not only associated with biofilm formation, as planktonic cultures incubated in 3× TSBg in the presence of gentamicin also showed antibiotic resistance. These findings appeared specific for aminoglycosides because biofilm formation was inhibited in all three growth media supplemented with bactericidal concentrations of the cell wall-active antibiotics, ampicillin and vancomycin. Additional experiments showed that the ability of 3× TSBg to overcome the antibacterial effects of gentamicin was associated with decreased uptake of gentamicin by S. aureus. Uptake is known to be decreased at low pH, and the kinetic change in pH of growth medium from biofilms incubated in 5 µg gentamicin ml−1 in the presence of 3× TSBg was decreased when compared with pH determinations from biofilms formed in 1/3× or 1× TSBg. These studies underscore the importance of environmental factors, including nutrient concentration and pH, on the antibiotic susceptibility of S. aureus planktonic and biofilm bacteria.

Radiolabeled r-Hirudin as a Measure of Thrombin Activity at, or within, the Rabbit Aorta Wall In Vitro and In Vivo

1994 ◽  
Vol 71 (04) ◽  
pp. 499-506 ◽  
Author(s):  
Mark W C Hatton ◽  
Bonnie Ross-Ouellet
Keyword(s):  
Rabbit Aorta ◽  
Balloon Injury ◽  
Recombinant Hirudin ◽  
Aorta Wall ◽  
Thrombin Activity ◽  
Before And After ◽  
The Matrix

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.

scholarly journals An In Vitro Coumarin-Antibiotic Combination Treatment of Pseudomonas aeruginosa Biofilms

2021 ◽  
Vol 16 (1) ◽  
pp. 1934578X2098774
Author(s):  
Jinpeng Zou ◽  
Yang Liu ◽  
Ruiwei Guo ◽  
Yu Tang ◽  
Zhengrong Shi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Combination Treatment ◽  
Crude Extract ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antibacterial Properties ◽  
Biofilm Growth ◽  
Antibiotic Combination

The drug resistance of Pseudomonas aeruginosa is a worldwide problem due to its great threat to human health. A crude extract of Angelica dahurica has been proved to have antibacterial properties, which suggested that it may be able to inhibit the biofilm formation of P. aeruginosa; initial exploration had shown that the crude extract could inhibit the growth of P. aeruginosa effectively. After the adaptive dose of coumarin was confirmed to be a potential treatment for the bacteria’s drug resistance, “coumarin-antibiotic combination treatments” (3 coumarins—simple coumarin, imperatorin, and isoimperatorin—combined with 2 antibiotics—ampicillin and ceftazidime) were examined to determine their capability to inhibit P. aeruginosa. The final results showed that (1) coumarin with either ampicillin or ceftazidime significantly inhibited the biofilm formation of P. aeruginosa; (2) coumarin could directly destroy mature biofilms; and (3) the combination treatment can synergistically enhance the inhibition of biofilm formation, which could significantly reduce the usage of antibiotics and bacterial resistance. To sum up, a coumarin-antibiotic combination treatment may be a potential way to inhibit the biofilm growth of P. aeruginosa and provides a reference for antibiotic resistance treatment.

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