Antimicrobial and barrier effects of silver against methicillin-resistant Staphylococcus aureus.
OBJECTIVE
Two strains of methicillin-resistant Staphylococcus aureus (MRSA), termed epidemic strains (EMRSA-15 and EMRSA-16), were used to evaluate the antimicrobial and barrier effect of four silver dressings (two silver donating and two non-silver-donating) available in the UK at the time of the study.


METHODS
The moist surface of a blood agar plate was covered with 10(6) colony-forming units of the respective strain of MRSA, and dressings were applied to the surface and incubated at 37 degrees C for different time periods and the upper and lower surfaces subcultured for residual growth.


RESULTS
The nanocrystalline dressings (silver donating) were effective as a barrier from one hour until the study end (72 hours): no penetration of EMRSA-15 and EMRSA-16 through the dressing occurred. Moreover, the nanocrystalline dressings showed some antimicrobial activity at one hour in the areas underneath and surrounding the dressing until the study end. The remaining two dressings had no barrier effect and only demonstrated limited antimicrobial activity after 24 hours.


CONCLUSIONS
This in vitro study suggests that the nanocrystalline dressings are more effective than other silver dressings in terms of providing a barrier function and antimicrobial activity against EMRSA-15 and EMRSA-16.
Edwards-Jones
V
V
Research Development Unit, St Augustine's, Manchester Metropolitan University, Manchester, UK. v.e.jones@mmu.ac.uk
D000279:Administration, Cutaneous; D000362:Agar; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use*; D002266:Carboxymethylcellulose Sodium / Q000627:therapeutic use*; D003470:Culture Media; D004353:Drug Evaluation, Preclinical; D006801:Humans; D017053:Infection Control; D016106:Methicillin Resistance; D049329:Nanostructures; D011091:Polyesters / Q000627:therapeutic use*; D011095:Polyethylenes / Q000627:therapeutic use*; D012834:Silver / Q000627:therapeutic use*; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013997:Time Factors; D014946:Wound Infection / Q000188:drug therapy* / Q000382:microbiology
C117408:Acticoat; D000891:Anti-Infective Agents, Local; D003470:Culture Media; D011091:Polyesters; D011095:Polyethylenes; D012834:Silver; D000362:Agar; D002266:Carboxymethylcellulose Sodium