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Staphylococcus aureus and Staphylococcus epidermidis are considered two of the most important pathogens, and their biofilms frequently cause device-associated infections. Microbial biosurfactants recently emerged as a new generation of anti-adhesive and anti-biofilm agents for coating implantable devices to preserve biocompatibility. In this study, R89 biosurfactant (R89BS) was evaluated as an anti-biofilm coating on medical-grade silicone. R89BS is composed of homologues of the mono- (75%) and di-rhamnolipid (25%) families, as evidenced by mass spectrometry analysis. The antimicrobial activity against Staphylococcus spp. planktonic and sessile cells was evaluated by microdilution and metabolic activity assays. R89BS inhibited S. aureus and S. epidermidis growth with minimal inhibitory concentrations (MIC 99 ) of 0.06 and 0.12 mg/mL, respectively and dispersed their pre-formed biofilms up to 93%. Silicone elastomeric discs (SEDs) coated by R89BS simple adsorption significantly counteracted Staphylococcus spp. biofilm formation, in terms of both built-up biomass (up to 60% inhibition at 72 h) and cell metabolic activity (up to 68% inhibition at 72 h). SEM analysis revealed significant inhibition of the amount of biofilm-covered surface. No cytotoxic effect on eukaryotic cells was detected at concentrations up to 0.2 mg/mL. R89BS-coated SEDs satisfy biocompatibility requirements for leaching products. Results indicate that rhamnolipid coatings are effective anti-biofilm treatments and represent a promising strategy for the prevention of infection associated with implantable devices.

Microbial biofilms play a dominant role in the failure of endodontic therapies. Bacterial adhesion is the first step in the establishment of biofilms, activating the host immune response leading to tissue damage. Biosurfactants are microbe‐derived tensioactive molecules with latent anti‐adhesive and anti‐microbial activity. This study reports the extraction and characterization of a biosurfactant from Lactobacillus (L.) plantarum (Lp‐BS) and investigates its anti‐microbial and anti‐adhesive properties compared to rhamnolipid, a commercially available biosurfactant. Lp‐BS, extracted from L. plantarum during the growth phase, was characterized as a glycoprotein, able to reduce surface tension and emulsify non‐polar liquids. Proteomic analysis of Lp‐BS identified three bacterial adhesin‐like proteins, suggesting roles in hindering bacterial adhesion. Lp‐BS did not show significant anti‐microbial activity against endodontic pathogens from the Streptococcus (Strep.) anginosus group or Enterococcus (Ent.) faecalis at 50 mg/ml. However, anti‐adhesive activity on abiotic surfaces was observed against both Strep. anginosus and Strep. intermedius. Rhamnolipid exhibited strong anti‐microbial activity, with minimum inhibitory concentrations of 0.097 mg/ml against Strep. anginosus, and 0.048 mg/ml against Strep. constellatus and Strep. intermedius, in addition to a marked anti‐adhesive activity. These findings offer preliminary evidence for the potential application of biosurfactants as an anti‐microbial and/or anti‐adhesive pharmacotherapy in endodontics. [ABSTRACT FROM AUTHOR]

Owing to their natural origin and environmental compatibility, interest in microbial surfactants or biosurfactants has gained attention during last few years. These characteristics fulfill the demand of regulatory agencies and society to use more sustained and green chemicals. Microbial-derived surfactants can replace synthetic surfactants in a great variety of industrial applications as detergents, foaming, emulsifiers, solubilizers, and wetting agents. Change in the trend of consumers toward natural from synthetic additives and the increasing health and environmental concerns have created demand for new "green" additives in foods. Apart from their inherent surface-active properties, biosurfactants have shown antimicrobial and anti-biofilm activities against food pathogens; therefore, biosurfactants can be versatile additives or ingredients of food processing. These interesting applications will be discussed in this review. [ABSTRACT FROM AUTHOR]

Biofilm formation on dental biomaterials is implicated in various oral health problems. Thus the challenge is to prevent the formation of this consortium of microorganisms using a safe approach such as antimicrobial and anti-adhesive natural products. Indeed, in the present study, the effects of an antifungal extract of Bacillus sp., isolated from plant rhizosphere, on the surface physicochemical properties of cobalt and nickel based dental alloys were studied using the contact angle measurements. Furthermore, in order to predict the adhesion of Candida albicans to the treated and untreated dental alloys, the total free energy of adhesion was calculated based on the extended Derjaguin-Landau-Verwey-Overbeek approach. Results showed hydrophobic and weak electron-donor and electron-acceptor characteristics of both untreated dental alloys. After treatment with the antifungal extract, the surface free energy of both dental alloys was influenced significantly, mostly for cobalt based alloy. In fact, treated cobalt based alloy became hydrophilic and predominantly electron donating. Those effects were time-dependent. Consequently, the total free energy of adhesion of C . albicans to this alloy became unfavorable after treatment with the investigated microbial extract. A linear relationship between the electron-donor property and the total free energy of adhesion has been found for both dental alloys. Also, a linear relationship has been found between this latter and the hydrophobicity for the cobalt based alloy. However, the exposure of nickel based alloy to the antifungal extract failed to produce the same effect. [ABSTRACT FROM AUTHOR]

Prosthetic joint infection (PJI) is a feared complication of total joint arthroplasty associated with increased morbidity and mortality. There is a growing body of evidence that bacterial colonization and biofilm formation are critical pathogenic events in PJI. Thus, the choice of biomaterials for implanted prostheses and their surface modifications may significantly influence the development of PJI. Currently, silver nanoparticle (AgNP) technology is receiving much interest in the field of orthopaedics for its antimicrobial properties and a strong anti-biofilm potential. The great advantage of AgNP surface modification is a minimal release of active substances into the surrounding tissue and a long period of effectiveness. As a result, a controlled release of AgNPs could ensure antibacterial protection throughout the life of the implant. Moreover, the antibacterial effect of AgNPs may be strengthened in combination with conventional antibiotics and other antimicrobial agents. Here, our main attention is devoted to general guidelines for the design of antibacterial biomaterials protected by AgNPs, its benefits, side effects and future perspectives in PJI prevention. [ABSTRACT FROM AUTHOR]

Biofilm matrices formed by irreversibly surface-anchored bacteria cause significant economic damage in the industrial and biomedical environments. The ubiquity of biofilms promotes increased investment in the development of technologies that will impede bacteria-surface association. Certain surface topographical fabrications may aid in preventing colonization. Herein, algal-secreted polysaccharide (Ps) biomaterial patches and metal complex films (MCF) are examined for their anti- Acinetobacter baumannii and anti- Pseudomonas aeruginosa biofilm properties. Ps moderately reduces biofilm formation; the Cu-MCF coating has significant anti-biofim activity while Zn-MCF had no effect. A mechanistic examination of these effects shows a two-fold greater coverage of the anti-adhesive surface of Cu-MCF than that of the control due to the induction of swarming motility, thus impeding bacterial transformation to the irreversibly attached state. Chemical compositions of the coatings and the interactions between coating components are examined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectrometry. Cu-MCF surface morphology comprises protruding needle-like structures up to 100 nm in height that are lacking in both the Ps and the Zn-MCF. Their presence in an aqueous solution is yet unproven and role in preventing their bacterial attachment open to speculation. The present study highlights the need to generate novel biomaterials that integrate naturally occurring anti-adhesive polymers with specific metal ions to improve the chemical, physical and biological properties of these anti-adhesive surfaces. Cu-MCF complexes fabricated with thermal and pressure stability to prevent metal ion leakage hold promise for a broad spectrum of industrial and medical anti-biofilm applications. [ABSTRACT FROM AUTHOR]

Objective(s): Serratia marcescens is one of the nosocomial pathogen. The ability to form biofilm is an important feature in the pathogenesis of S. marcescens. The aim of this study was to determine the anti-adhesive properties of a biosurfactant isolated from Lactobacillus acidophilus ATCC 4356, on S. marcescens strains. Materials and Methods: Lactobacillus acidophilus ATCC 4356, was selected as a probiotic strain to produce biosurfactant. Anti-adhesive activities was determined by pre-coating and co- incubating methods in 96-well culture plates. Results: The FTIR analysis of derived biosurfactant revealed the composition as protein component. Because of the release of such biosurfactants, L. acidophilus was able to interfere with the adhesion and biofilm formation of the S. marcescens strains. In co- incubation method this biosurfactant in 2.5 mg/ml concentration showed anti-adhesive activity against all tested strains of S. marcescens (P<0.05). Conclusion: Our results show anti-adhesive properties of L. acidophilus biosurfactant will be useful against microorganisms responsible for infections in the urinary, vaginal and gastrointestinal tracts, as well as skin, making it a suitable alternative to conventional antibiotics. [ABSTRACT FROM AUTHOR]

Numerous investigations of microbial surface-active compounds or biosurfactants over the past two decades have led to the discovery of many interesting physicochemical and biological properties including antimicrobial, anti-biofilm and therapeutic among many other pharmaceutical and medical applications. Microbial control and inhibition strategies involving the use of antibiotics are becoming continually challenged due to the emergence of resistant strains mostly embedded within biofilm formations that are difficult to eradicate. Different aspects of antimicrobial and anti-biofilm control are becoming issues of increasing importance in clinical, hygiene, therapeutic and other applications. Biosurfactants research has resulted in increasing interest into their ability to inhibit microbial activity and disperse microbial biofilms in addition to being mostly nontoxic and stable at extremes conditions. Some biosurfactants are now in use in clinical, food and environmental fields, whilst others remain under investigation and development. The dispersal properties of biosurfactants have been shown to rival that of conventional inhibitory agents against bacterial, fungal and yeast biofilms as well as viral membrane structures. This presents them as potential candidates for future uses in new generations of antimicrobial agents or as adjuvants to other antibiotics and use as preservatives for microbial suppression and eradication strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new UHPLC-MS method was used assuring a faster sophorolipids analysis. • Automatic Flash Chromatography allowed the purification of several SLs. • Purified L-C18:0 and L-C18:1 diacetylated SLs showed higher antimicrobial activity. • Antiadhesive properties of surface-bonded acidic SLs reduced biofilm formation. • L-C18:1 diacateylated SL release was the most promising regarding efficacy and safety. Staphylococcus aureus medical devices related-infections, such as blood stream catheter are of major concern. Their prevention is compulsory and strategies, not prone to the development of resistance, to prevent S. aureus biofilms on catheter surfaces (e.g. silicone) are needed. In this work two different approaches using sophorolipids were studied to prevent S. aureus biofilm formation on medical grade silicone: i) an antiadhesive strategy through covalent bond of sophorolipids to the surface; ii) and a release strategy using isolated most active sophorolipids. Sophorolipids produced by Starmerella bombicola , were characterized by UHPLC-MS and RMN, purified by automatic flash chromatography and tested for their antimicrobial activity towards S. aureus. Highest antimicrobial activity was observed for C18:0 and C18:1 diacetylated lactonic sophorolipids showing a MIC of 50 μg mL−1. Surface modification with acidic or lactonic sophorolipids when evaluating the anti-adhesive or release strategy, respectively, was confirmed by contact angle, FTIR-ATR and AFM analysis. When using a mixture of acidic sophorolipids covalently bonded to silicone surface as antiadhesive strategy cytocompatible surfaces were obtained and a reduction of 90 % on biofilm formation was observed. Nevertheless, if a release strategy is adopted with purified lactonic sophorolipids a higher effect is achieved. Most promising compound was C18:1 diacateylated lactonic sophorolipid that showed no cellular viability reduction when a concentration of 1.5 mg mL−1 was selected and a reduction on biofilm around 5 log units. Results reinforce the applicability of these antimicrobial biosurfactants on preventing biofilms and disclose that their antimicrobial effect is imperative when comparing to their antiadhesive properties. [ABSTRACT FROM AUTHOR]