Inhibition of microbial surface colonization Dotaz Zobrazit nápovědu
Development of anti-fouling surfaces is a major challenge in materials research. Microorganisms growing as biofilms have enhanced tolerance to antimicrobial strategies including antibiotics and antiseptics complicating the design of anti-fouling surfaces. Silver nanoparticles (AgNPs) are a promising antimicrobial technology with broad spectrum efficacy with a reduced likelihood of microorganisms developing resistance to the technology. This study tested the efficacy of new immobilized AgNP-modified surface technology against three common opportunistic pathogens grown either as monocultures or as cocultures. The presented study fills a gap in the literature by quantifying the efficacy of immobilized AgNP particles against multispecies biofilms. Polyethylene (PE) surfaces functionalized with the AgNPs were highly effective against Pseudomonas aeruginosa biofilms reducing viable cell counts by 99.8 % as compared to controls. However, the efficacy of the AgNP-modified PE surface was compromised when P. aeruginosa was cocultured with Candida albicans. Interspecies interactions can strongly influence the efficacy of anti-fouling AgNP coatings highlighting the need to test surfaces not only against biofilm phenotypes but under conditions representative of applications including the presence of multispecies consortia.
- Klíčová slova
- Antimicrobial surfaces, Biofilm, Inhibition of microbial surface colonization, Silver nanoparticles, Surface functionalization,
- Publikační typ
- časopisecké články MeSH
OBJECTIVE: The study aimed at determining the ability of lipophosphonoxin DR5026 to inhibit the formation of bacterial biofilm on the bone cement surface and assessing potential development of bacterial resistance. MATERIAL AND METHODS: Bone cement (Hi-Fatigue Bone Cement 2x40, aap Biomaterials GmbH, Germany) was polymerized with lipophosphonoxin DR5026. Cement samples were cultured using bacterial suspension containing Staphylococcus epidermidis CCM7221 at an inoculum density of 106 CFU/mL. After three, 24, and 48 hours of incubation at 35 °C, the number of bacteria adhered to the sample was measured and their growth curve was plotted. In 14 cycles, strains of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Streptococcus agalactiae were exposed to subinhibitory concentrations of DR5026 and the minimum inhibitory concentrations (MICs) were determined. RESULTS: After three hours of culture in the bacterial inoculum with an initial concentration of 106 CFU/mL, the number of colonies isolated from the cement sample treated with DR5026 was smaller by two orders of magnitude when compared to a control cement sample. After 24 and 48 hours of incubation, the number of CFU remained at 50 in the treated cement, whereas 109 CFU were cultured from control cement samples. The plotted growth curves for bacteria adhered to cements clearly showed the inhibitory effect of lipophosphonoxin on their growth and multiplication, particularly after 48 hours. Following 14 cycles of repeated exposure to subinhibitory concentrations of DR5026, no increase in MICs was noted in the tested strains. CONCLUSION: Lipophosphonoxin DR5026 used to treat bone cement was found to have antibacterial effects and to inhibit the formation of bacterial biofilm. Repeated exposure of the tested bacteria to subinhibitory concentrations of the above lipophosphonoxin did not induce their resistance or increase their MICs.Key words: bone cement - joint replacement infections - lipophosphonoxins - antibacterial effect - biofilm.
Microbial biofilms are factions of surface-colonized cells encompassed in a matrix of extracellular polymeric substances. Profound application of antibiotics in order to treat infections due to microbial biofilm has led to the emergence of several drug-resistant microbial strains. In this context, a novel type of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz)-capped silver nanoparticles (TzAgNPs) was synthesized, and efforts were given to test its antimicrobial and antibiofilm activities against Pseudomonas aeruginosa, a widely used biofilm-forming pathogenic organism. The synthesized TzAgNPs showed considerable antimicrobial activity wherein the MIC value of TzAgNPs was found at 40 μg/mL against Pseudomonas aeruginosa. Antibiofilm activity of TzAgNPs was also tested against Pseudomonas aeruginosa by carrying out an array of experiments like microscopic observation, crystal violet assay, and protein count using the sub-MIC doses of TzAgNPs. Since TzAgNPs showed efficient antibiofilm activity, thus, in the present study, efforts were put together to investigate the underlying cause of biofilm attenuation of Pseudomonas aeruginosa by using TzAgNPs. To this end, we discerned that the sub-MIC doses of TzAgNPs increased ROS level considerably in the bacterial cell. The result showed that the ROS level and microbial biofilm formation are inversely proportional. Thus, the attenuation in microbial biofilm could be attributed to the accumulation of ROS level. Furthermore, it was also duly noted that microorganisms upon treatment with TzAgNPs exhibited considerable diminution in virulence factors (protease and pyocyanin) in contrast to the control where the organisms were not treated with TzAgNPs. Thus, the results indicated that TzAgNPs exhibit considerable reduction in the development of biofilms and spreading of virulence factors. Taken together, all the results indicated that TzAgNPs could be deemed to be a promising agent for the prevention of microbial biofilm development that might assist to fight against infections linked to biofilm.
- MeSH
- antibakteriální látky chemická syntéza farmakologie MeSH
- biofilmy účinky léků MeSH
- faktory virulence MeSH
- kovové nanočástice * MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiální viabilita účinky léků MeSH
- pseudomonádové infekce metabolismus mikrobiologie MeSH
- Pseudomonas aeruginosa účinky léků fyziologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- stříbro * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- faktory virulence MeSH
- reaktivní formy kyslíku MeSH
- stříbro * MeSH
Surface modification of various polymer foils was achieved by UV activation and chemical grafting with cysteamine to improve surface properties and antimicrobial efficacy. UVC activation at 254 nm led to changes in surface wettability and charge density, which allowed the introduction of amino and thiol functional groups by cysteamine grafting. X-ray photoelectron spectroscopy (XPS) confirmed increased nitrogen and sulfur content on the modified surfaces. SEM analysis revealed that UV activation and cysteamine grafting resulted in distinct surface roughness and texturing, which are expected to enhance microbial interactions. Antimicrobial tests showed increased resistance to algal growth (inhibition test) and bacterial colonization (drop plate method), with significant improvement observed for polyethylene terephthalate (PET) and polyetheretherketone (PEEK) foils. The important factors influencing the efficacy included UV exposure time and cysteamine concentration, with longer exposure and higher concentrations leading to bacterial reduction of up to 45.7% for Escherichia coli and 55.6% for Staphylococcus epidermidis. These findings highlight the potential of combining UV activation and cysteamine grafting as an effective method for developing polymeric materials with enhanced antimicrobial function, offering applications in industries such as healthcare and packaging.
- Klíčová slova
- UV radiation, antimicrobial activity, chemical grafting, polymer foils, zeta potential,
- Publikační typ
- časopisecké články MeSH
Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.
- MeSH
- antiinfekční látky * chemie farmakologie MeSH
- cévní protézy mikrobiologie MeSH
- chitosan * chemie farmakologie MeSH
- fosfáty * chemie farmakologie MeSH
- ionty chemie MeSH
- kyselina hyaluronová * chemie farmakologie MeSH
- lidé MeSH
- nanočástice chemie ultrastruktura MeSH
- skot MeSH
- sloučeniny stříbra * chemie farmakologie MeSH
- Staphylococcus aureus růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- antiinfekční látky * MeSH
- chitosan * MeSH
- fosfáty * MeSH
- ionty MeSH
- kyselina hyaluronová * MeSH
- silver phosphate MeSH Prohlížeč
- sloučeniny stříbra * MeSH
Adhesion of bacteria to epithelial tissue is an essential step in the progression of the urinary tract infections. Reduction of virulence factors responsible for microbial attachment may help to decrease or inhibit colonization of the host organism by pathogens. In the age of increasing bacterial antibiotic resistance, more and more attention is being paid to the use of plants and/or their bioactive components in the prevention and treatment of human infections. Asiatic acid (AA) and ursolic acid (UA), two plant secondary metabolites, were used as potential antibacterial agents. The current study aimed to determine the possible impact of AA and UA on morphology, hydrophobicity, and adhesion of clinical uropathogenic Escherichia coli strains (UPEC) to the uroepithelial cells. Our work describes for the first time the effects exerted by AA and UA on virulence factors of UPECs. The impact of both acids on the cell surface hydrophobicity of the investigated strains was very weak. The results clearly show the influence of AA and UA on the presence of P fimbriae and curli fibers, morphology of the UPECs cells and their adhesion to epithelium; however, some differences between activities of AA and UA were found.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální adheze účinky léků MeSH
- epitelové buňky cytologie mikrobiologie MeSH
- faktory virulence MeSH
- fylogeneze MeSH
- hydrofobní a hydrofilní interakce účinky léků MeSH
- kultivované buňky MeSH
- kyselina ursolová MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- pentacyklické triterpeny farmakologie MeSH
- rostlinné extrakty farmakologie MeSH
- sekvenční analýza DNA MeSH
- triterpeny farmakologie MeSH
- uropatogenní Escherichia coli účinky léků růst a vývoj MeSH
- urotel cytologie mikrobiologie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- asiatic acid MeSH Prohlížeč
- faktory virulence MeSH
- pentacyklické triterpeny MeSH
- rostlinné extrakty MeSH
- triterpeny MeSH
Human milk is the gold standard for nourishment of early infants because it contains a number of bioactive components, such as human milk oligosaccharides (HMOs). The high concentration and structural diversity of HMOs are unique to humans. HMOs are a group of complex and diverse glycans that are resistant to gastrointestinal digestion and reach the infant colon as the first prebiotics. N-acetyl-glucosamine containing oligosaccharides were first identified 50 years ago as the 'bifidus factor', a selective growth substrate for intestinal bifidobacteria, thus providing a conceptual basis for HMO-specific bifidogenic activity. Bifidobacterial species are the main utilisers of HMOs in the gastrointestinal tract and represent the dominant microbiota of breast-fed infants, and they may play an important role in maintaining the general health of newborn children. Oligosaccharides are also known to directly interact with the surface of pathogenic bacteria, and various oligosaccharides in milk are believed to inhibit the binding of pathogens and toxins to host cell receptors. Furthermore, HMOs are thought to contribute to the development of infant intestine and brain. Oligosaccharides currently added to infant formula are structurally different from the oligosaccharides naturally occurring in human milk and, therefore, they are unlikely to mimic some of the structure-specific effects. In this review, we describe how HMOs can modulate gut microbiota. This article summarises information up to date about the relationship between the intestinal microbiota and HMOs, and other possible indirect effects of HMOs on intestinal environment.
- Klíčová slova
- anti-adhesive properties, human milk oligosaccharides, intestinal bacteria, sialic acid,
- MeSH
- acetylglukosamin farmakologie MeSH
- antiinfekční látky farmakologie MeSH
- Bifidobacterium MeSH
- kojenec MeSH
- kyselina N-acetylneuraminová farmakologie MeSH
- lidé MeSH
- mateřské mléko * MeSH
- mikrobiota účinky léků MeSH
- mozek růst a vývoj MeSH
- náhražky mateřského mléka farmakologie MeSH
- novorozenec MeSH
- oligosacharidy farmakologie MeSH
- prebiotika MeSH
- střeva mikrobiologie MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- acetylglukosamin MeSH
- antiinfekční látky MeSH
- kyselina N-acetylneuraminová MeSH
- oligosacharidy MeSH
- prebiotika MeSH
Antibiotic resistance is currently a serious health problem. Since the discovery of new antibiotics no longer seems to be a sufficient tool in the fight against multidrug-resistant infections, adjuvant (combination) therapy is gaining in importance as well as reducing bacterial virulence. Silymarin is a complex of flavonoids and flavonolignans known for its broad spectrum of biological activities, including its ability to modulate drug resistance in cancer. This work aimed to test eleven, optically pure silymarin flavonolignans for their ability to reverse the multidrug resistance phenotype of Staphylococcus aureus and reduce its virulence. Silybin A, 2,3-dehydrosilybin B, and 2,3-dehydrosilybin AB completely reversed antibiotic resistance at concentrations of 20 µM or less. Both 2,3-dehydrosilybin B and AB decreased the antibiotic-induced gene expression of representative efflux pumps belonging to the major facilitator (MFS), multidrug and toxic compound extrusion (MATE), and ATP-binding cassette (ABC) families. 2,3-Dehydrosilybin B also inhibited ethidium bromide accumulation and efflux in a clinical isolate whose NorA and MdeA overproduction was induced by antibiotics. Most of the tested flavonolignans reduced cell-to-cell communication on a tetrahydrofuran-borate (autoinducer-2) basis, with isosilychristin leading the way followed by 2,3-dehydrosilybin A and AB, which halved communication at 10 µM. Anhydrosilychristin was the only compound that reduced communication based on acyl-homoserine lactone (autoinducer 1), with an IC50 of 4.8 µM. Except for isosilychristin and anhydrosilychristin, all of the flavonolignans inhibited S. aureus surface colonization, with 2,3-dehydrosilybin A being the most active (IC50 10.6 µM). In conclusion, the selected flavonolignans, particularly derivatives of 2,3-dehydrosilybin B, 2,3-dehydrosilybin AB, and silybin A are non-toxic modulators of S. aureus multidrug resistance and can decrease the virulence of the bacterium, which deserves further detailed research.
- Klíčová slova
- Efflux pump, Flavonolignans, Multidrug resistance, Silybin, Silychristin, Staphylococcus aureus,
- MeSH
- antibakteriální látky farmakologie MeSH
- antibiotická rezistence MeSH
- lidé MeSH
- silibinin farmakologie MeSH
- silymarin * chemie farmakologie MeSH
- stafylokokové infekce * MeSH
- Staphylococcus aureus MeSH
- virulence MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- silibinin MeSH
- silymarin * MeSH
Urinary tract infections, most of which are biofilm infections in catheterized patients, account for more than 40% of hospital infections. Bacterial colonization of the urinary tract and catheters causes not only infection but also other complications such as catheter blockage by bacterial encrustation, urolithiasis and pyelonephritis. About 50% of long-term catheterized patients face urinary flow obstruction due to catheter encrustation, but no measure is currently available to prevent it. Encrustation has been known either to result from metabolic dysfunction or to be of microbial origin, with urease positive bacterial species implicated most often. Infectious calculi account for about 15-20% of all cases of urolithiasis and are often associated with biofilm colonization of a long-term indwelling urinary catheter or urethral stent. The use of closed catheter systems is helpful in reducing such problems; nevertheless, such a system only delays the inevitable, with infections emerging a little later. Various coatings intended to prevent the bacterial adhesion to the surface of catheters and implants and thus also the emergence of biofilm infections, unfortunately, do not inhibit the microbial adhesion completely and permanently and the only reliable method for biofilm eradication remains the removal of the foreign body from the patient.
The interface between the organism and the outside world, which is the site of exchange of nutrients, export of products and waste components, must be selectively permeable and at the same time, it must constitute a barrier equipped with local defense mechanisms against environmental threats (e.g. invading pathogens). The boundaries with the environment (mucosal and skin surfaces) are therefore covered with special epithelial layers which support this barrier function. The immune system, associated with mucosal surfaces covering the largest area of the body (200-300 m(2)), evolved mechanisms discriminating between harmless antigens and commensal microorganisms and dangerous pathogens. The innate mucosal immune system, represented by epithelial and other mucosal cells and their products, is able to recognize the conserved pathogenic patterns on microbes by pattern recognition receptors such as Toll-like receptors, CD14 and others. As documented in experimental gnotobiotic models, highly protective colonization of mucosal surfaces by commensals has an important stimulatory effect on postnatal development of immune responses, metabolic processes (e.g. nutrition) and other host activities; these local and systemic immune responses are later replaced by inhibition, i.e. by induction of mucosal (oral) tolerance. Characteristic features of mucosal immunity distinguishing it from systemic immunity are: strongly developed mechanisms of innate defense, the existence of characteristic populations of unique types of lymphocytes, colonization of the mucosal and exocrine glands by cells originating from the mucosal organized tissues ('common mucosal system') and preferential induction of inhibition of the responses to nondangerous antigens (mucosal tolerance). Many chronic diseases, including allergy, may occur as a result of genetically based or environmentally induced changes in mechanisms regulating mucosal immunity and tolerance; this leads to impaired mucosal barrier function, disturbed exclusion and increased penetration of microbial, food or airborne antigens into the circulation and consequently to exaggerated and generalized immune responses to mucosally occurring antigens, allergens, superantigens and mitogens.
- MeSH
- alergie imunologie MeSH
- epitel imunologie MeSH
- imunologická tolerance MeSH
- imunoterapie MeSH
- lidé MeSH
- sliznice imunologie MeSH
- slizniční imunita imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
