Adhesion of Methicillin-Resistant Staphylococcus aureus and Candida albicans to Parylene-C-Coated Polymethyl Methacrylate.

PURPOSE: To determine whether coating polymethyl methacrylate (PMMA) discs with Parylene-C would reduce Staphylococcus aureus and Candida albicans biofilm formation. MATERIALS AND METHODS: MRSA and Candida albicans single and dual biofilms were grown for 48 hours in artificial saliva on parylene-C-coated or uncoated PMMA, and the viable biofilm colony-forming units were counted. RESULTS: There was no significant difference in the count of viable methicillin-resistant Staphylococcus aureus or Candida albicans recovered from single- or dual-species biofilms between coated and uncoated PMMA discs. CONCLUSION: Parylene-C does not prevent biofilm formation on PMMA.

Aggregatibacter actinomycetemcomitans serotype prevalence and antibiotic resistance in a UK population with periodontitis.

OBJECTIVES: Aggregatibacter actinomycetemcomitans is a recognised pathogen involved in aggressive periodontitis. Seven serotypes of A. actinomycetemcomitans exist with a range of virulence and distribution dependent on ethnicity and geography. The ability of A. actinomycetemcomitans to invade soft tissue can necessitate the use of systemic antibiotics for treatment, however variations in its antibiotic susceptibility exist dependent on geographical location. METHODS: Serotypes of A. actinomycetemcomitans isolates from a UK cohort of 50 patients with aggressive periodontitis were determined by PCR. Resistance of the isolates to eight antibiotics [penicillin (1U), amoxicillin (2µg), amoxicillin/clavulanic acid (30µg), metronidazole (5µg), clindamycin (2µg), tetracycline (10µg), ciprofloxacin (5µg) and ceftazidime (30µg)] were determined by disk diffusion according to BSAC guidelines. RESULTS: Prevalences of serotypes a, c, b, e and mixed serotypes were 48%, 22%, 2%, 2% and 12%, respectively. The serotype of isolates from seven patients (14%) could not be deduced by PCR. Of the 56 isolates tested, 100% were resistant to penicillin and metronidazole, 87.5% to clindamycin, 83.9% to amoxicillin and 76.8% to ceftazidime. Low rates of resistance to tetracycline (8.9% resistant) and amoxicillin/clavulanic acid (14.3% resistant) were observed, whereas no isolates were resistant to ciprofloxacin. CONCLUSIONS: As in a number of publications the suggested treatment of aggressive periodontitis includes the combined use of amoxicillin with metronidazole, these results highlight the need for culture and antimicrobial susceptibility investigations in patients with aggressive periodontitis prior to systemic use of antibiotics concomitantly to periodontal therapy.

In vitro evaluation of the antibiofilm properties of chlorhexidine and delmopinol on dental implant surfaces.

Biofilm development on the internal surfaces of dental implants and dental implant components may be associated with peri-implant hard and soft tissue abnormalities. Currently, no protocols have been established for effective disinfection of removable implant components. The purpose of this study was to evaluate the antibiofilm properties of commonly used dental antimicrobial agents (chlorhexidine and delmopinol) on multispecies biofilms. Biofilms of 48 h and 168 h maturity were exposed to 0.2% chlorhexidine, 2% chlorhexidine and a product containing 0.2% delmopinol for 5, 10 and 20 min. 2% chlorhexidine was the most effective agent, achieving a total viable biofilm reduction ranging from 96.2% to >99.99% depending on the time of exposure and the stage of biofilm development.