BACKGROUND: Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL) mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s) showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors. METHODS AND RESULTS: Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136.
Although biofilms are formed on a variety of surfaces, of utmost significance are those formed on prosthetic devices used as implants. Such biofilms can lead to severe device-related infections that are difficult to treat. In a search for new antibiofilm agents that can be used as "active" implant coatings, purified fraction from a tannin-rich extract of Terminalia chebula was isolated and tested for its antibiofilm properties on a titanium implant material.
Candida albicans is one of the most prevalent human opportunistic pathogens. C. albicans undergoes a yeast-to-hyphal transition that has been identified as a virulence factor as well as a critical element for mature biofilm formation. A previous study in our lab showed retigeric acid B (RAB), a lichen derived pentacyclic triterpenoid, displayed synergistic antifungal activity with azoles. We now showed that this combination also proved to be adequate in combating the formation of hyphae in vitro.
Quorum sensing (QS) is a key regulator of virulence and biofilm formation in Pseudomonas aeruginosa and other medically relevant bacteria. Aqueous extracts of six plants, Conocarpus erectus, Chamaesyce hypericifolia, Callistemon viminalis, Bucida buceras, Tetrazygia bicolor, and Quercus virginiana, were examined in this study for their effects on P. aeruginosa virulence factors and the QS system. C. erectus, B. buceras, and C. viminalis caused a significant inhibition of LasA protease, LasB elastase, pyoverdin production, and biofilm formation.
AIM OF STUDY: One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infection (SSTI). Staphylococcus aureus, a common cause of SSTI, has generated increasing concern due to drug resistance. Many plants possess antimicrobial agents and provide effective remedies for SSTI. Our aim was to investigate plants from different ethnobotanical usage groups for inhibition of growth and biofilms in methicillin-resistant Staphylococcus aureus (MRSA).
BACKGROUND: Commensal-derived probiotic bacteria inhibit enteric pathogens and regulate host immune responses in the gastrointestinal tract, but studies examining specific functions of beneficial microbes in the context of biofilms have been limited in scope. RESULTS: Lactobacillus reuteri formed biofilms that retained functions potentially advantageous to the host including modulation of cytokine output and the production of the antimicrobial agent, reuterin. Immunomodulatory activities of biofilms were demonstrated by the abilities of specific L.
Cranberry crude extracts, in various vehicles, have shown inhibitory effects on the formation of oral biofilms in vitro. The presence of proanthocyanidins (PAC) in cranberry extracts has been linked to biological activities against specific virulence attributes of Streptococcus mutans, e.g. the inhibition of glucosyltransferase (Gtf) activity. The aim of the present study was to determine the influence of a highly purified and chemically defined cranberry PAC fraction on S.
The genomes of four Lactobacillus reuteri strains isolated from human breast milk and the gastrointestinal tract have been recently sequenced as part of the Human Microbiome Project. Preliminary genome comparisons suggested that these strains belong to two different clades, previously shown to differ with respect to antimicrobial production, biofilm formation, and immunomodulation.
BACKGROUND: Biofilms contribute to the pathogenesis of many forms of Staphylococcus aureus infection. Treatment of these infections is complicated by intrinsic resistance to conventional antibiotics, thus creating an urgent need for strategies that can be used for the prevention and treatment of biofilm-associated infections. METHODOLOGY/PRINCIPAL FINDINGS: This study demonstrates that a botanical natural product composition (220D-F2) rich in ellagic acid and its derivatives can limit S. aureus biofilm formation to a degree that can be correlated with increased antibiotic susceptibility.
ETHNOPHARMACOLOGICAL RELEVANCE: Quercus cerris L., Fagaceae has been used in traditional Mediterranean medicine for numerous purposes, including anti-infective therapies for diarrhea and wound care. AIM OF THE STUDY: To evaluate the anti-staphylococcal activity of fractions of ethanolic extracts of Quercus cerris leaf and stem/fruit samples in models for biofilm and growth inhibition. MATERIALS AND METHODS: Ethanolic extracts of Quercus cerris leaves and stems/fruits were prepared, resuspended in water and fractioned by successively partitioning with hexane, ethyl acetate and butanol.