Cytotoxicity of topical antimicrobial agents used in burn wounds in Australasia.
BACKGROUND
Burn sepsis is a leading cause of mortality and morbidity in patients with major burns. The use of topical antimicrobial agents has helped improve the survival of these patients. Silvazine (Sigma Pharmaceuticals, Melbourne, Australia) (1% silver sulphadiazine and 0.2% chlorhexidine digluconate) is used exclusively in Australasia, and there is no published study on its cytotoxicity. This study compared the relative cytotoxicity of Silvazine with 1% silver sulphadiazine (Flamazine (Smith & Nephew Healthcare, Hull, UK)) and a silver-based dressing (Acticoat (Smith & Nephew Healthcare, Hull, UK)).


METHODS
Dressings were applied to the centre of culture plates that were then seeded with keratinocytes at an estimated 25% confluence. The plates were incubated for 72 h and culture medium and dressings then removed. Toluidine blue was added to stain the remaining keratinocytes. Following removal of the dye, the plates were photographed under standard conditions and these digital images were analysed using image analysis software. Data was analysed using Student's t-test.


RESULTS
In the present study, Silvazine is the most cytotoxic agent. Seventy-two hour exposure to Silvazine in the present study results in almost no keratinocyte survival at all and a highly statistically significant reduction in cell survival relative to control, Acticoat and Flamazine (P<0.001, P<0.01, P<0.01, respectively). Flamazine is associated with a statistically significant reduction in cell numbers relative to control (P<0.05), but is much less cytotoxic than Silvazine (P<0.005).


CONCLUSIONS
In this in-vitro study comparing Acticoat, Silvazine and Flamazine, Silvazine shows an increased cytotoxic effect, relative to control, Flamazine and Acticoat. An in-vivo study is required to determine whether this effect is carried into the clinical setting.
Royal Children's Hospital Burns Research Group, Department of Paediatrics and Child Health, University of Queensland, Royal Children's Hospital, Brisbane, Queensland, Australia. j.fraser@uq.edu.au
John F
JF
Fraser
Leila
L
Cuttle
Margit
M
Kempf
Roy M
RM
Kimble
D000891:Anti-Infective Agents, Local / Q000633:toxicity*; D044362:Australasia; D001458:Bandages; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000633:toxicity*; D004338:Drug Combinations; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects*; D011091:Polyesters / Q000633:toxicity*; D011095:Polyethylenes / Q000633:toxicity*; D012837:Silver Sulfadiazine / Q000633:toxicity*
C117408:Acticoat; D000891:Anti-Infective Agents, Local; D004338:Drug Combinations; D011091:Polyesters; D011095:Polyethylenes; C010882:chlorhexidine gluconate; D002710:Chlorhexidine; D012837:Silver Sulfadiazine