Antimicrobial and Biofilm-Preventing Activity of l-Borneol Possessing 2(5H)-Furanone Derivative F131 against S. aureus—C. albicans Mixed Cultures

Efficacy of furanone in reducing the bacterial contamination and marginal bone loss of dental implants

In two-piece dental implants, gaps at the implant-abutment interface (IAI) allow bacterial contamination, contributing to peri-implantitis and marginal bone loss (MBL). This study investigates the clinical efficacy of (5Z)-4-bromo-5-(bromomethylene)-2(5 H)-furanone (furanone), a quorum sensing inhibitor, for mitigating bacterial contamination and MBL around dental implants. Dental implants with dog's bacteria and various concentrations of furanone were incubated anaerobically for 7 days to evaluate the anti-bacterial effect of furanone, and bacterial quantification was performed in vitro. The mandibular premolars and molars of three mongrel dogs were extracted three months before implant placement. After the implant fixture was placed, furanone and/or bacteria were added to the inner space of the fixture and connected with a healing abutment. The MBL was assessed by soft X-ray microscopy after 0, 2, 4, 8, and 16 weeks of implant placement. Furanone (20 and 30 mM) significantly inhibited bacterial growth at the IAI in vitro. The MBL at the IAI by bacterial contamination was reduced with furanone (20 mM) in vivo. Bacterial contamination at the IAI causes a substantial MBL, which can be effectively mitigated by furanone, thereby highlighting its potential as an antibacterial agent for reducing MBL for the long-term survival of the dental implants.

Biosurfactant complexed with arginine has antibiofilm activity against methicillin-resistant Staphylococcus aureus

Aim: The present study investigated the antimicrobial effectiveness of a rhamnolipid complexed with arginine (RLMIX_Arg) against planktonic cells and biofilms of methicillin-resistant Staphylococcus aureus (MRSA). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol: M07-A10, checkerboard test, biofilm in plates and catheters and flow cytometry were used. Result: RLMIX_Arg has bactericidal and synergistic activity with oxacillin. RLMIX_Arg inhibits the formation of MRSA biofilms on plates at sub-inhibitory concentrations and has antibiofilm action against MRSA in peripheral venous catheters. Catheters impregnated with RLMIX_Arg reduce the formation of MRSA biofilms. Conclusion: RLMIX_Arg exhibits potential for application in preventing infections related to methicillin-resistant S. aureus biofilms.

The Antimicrobial Potential of the Hop (Humulus lupulus L.) Extract against Staphylococcus aureus and Oral Streptococci

Plant extracts are in the focus of the pharmaceutical industry as potential antimicrobials for oral care due to their high antimicrobial activity coupled with low production costs and safety for eukaryotic cells. Here, we show that the extract from Hop (Humulus lupulus L.) exhibits antimicrobial activity against Staphylococcus aureus and Streptococci in both planktonic and biofilm-embedded forms. An extract was prepared by acetone extraction from hop infructescences, followed by purification and solubilization of the remaining fraction in ethanol. The effect of the extract on S. aureus (MSSA and MRSA) was comparable with the reference antibiotics (amikacin, ciprofloxacin, and ceftriaxone) and did not depend on the bacterial resistance to methicillin. The extract also demonstrated synergy with amikacin on six S. aureus clinical isolates, on four of six isolates with ciprofloxacin, and on three of six isolates with ceftriaxone. On various Streptococci, while demonstrating lower antimicrobial activity, an extract exhibited a considerable synergistic effect in combination with two of three of these antibiotics, decreasing their MIC up to 512-fold. Moreover, the extract was able to penetrate S. aureus and S. mutans biofilms, leading to almost complete bacterial death within them. The thin-layer chromatography and LC-MS of the extract revealed the presence of prenylated flavonoids (2',4',6',4-tetrahydroxy-3'-geranylchalcone) and acylphloroglucides (cohumulone, colupulone, humulone, and lupulone), apparently responsible for the observed antimicrobial activity and ability to increase the efficiency of antibiotics. Taken together, these data suggest an extract from H. lupulus as a promising antimicrobial agent for use both as a solely antiseptic and to potentiate conventional antimicrobials.