Korean J Dermatol.  1995 Oct;33(5):895-906.

A Comparative Study of Cytotoxicity of Topical Antimicrobials to Cultured Human Keratinocytes and Fibroblasts

• Pyo HC
• Kim YK
• Whang KU
• Park YL
• Eun HC

Abstract

The clinical use of topical antimicrobial substances is common in clean wounds as well as contaminated and chronic wounds. This use is based on the observation that the reduction of superficial bacterial contamination promotes wound healing. While the antibacterial efficacy of topical antimicrobials has been well documented, their effects on living tissue and the process of wound healing remain controversial. Recently, there have been several trials to detect the toxicity of various antimicrobial materials by using cultured fibroblasts and keratinocytes. In this study the cytotoxicity of several commonly used antimicrobials and the cytotoxic concentrations of antimicrobials on cultured human keratinocytes and fibroblasts were compared using 3 different
METHODS
1) the MTT method showing the ability of the cells to clear the cytotoxic agents, 2) LDH release indicating damage of cell membrane, and 3) tritiated thymidine incorporation measuring DNA synthesis. In the MTT method all topical antimicrobials in their usual clinical concentration showed cytotoxicity on both keratinocytes and fibroblasts by suppressing cell proliferation. Keratinocytes were more sensitive to certain antibiotics. When the 50% inhibition concentration (IC50) of topical antimicrobials were compared, the cytotoxicity to keratinocyte was, in the decreasing order, chlorhexidine, hydrogen peroxide, povidone iodine, sulfadiazine, fusidic acid, ethanol. Gentamicin and bacitracin. The cytotoxicity to fibroblasts was, in decreasing order, chiorhexidine, hydrogen peroxide, povidone iodine, fusidic acid, ethanol, sulfadiazine, bacitracin, and gentamicin. Most of the antimicrobials tested increased LDH release by keratinocyte in IC50.Chlorhexidine, hydrogen peroxide and povidone iodine showed statistically significant increase in LDH release. The tritiated thymidine incorporation study showed the order of cytotoxicity to keratinocyte in IC50 of each antimicrobials was similar to that of the MTT method. Tritiated thymidined incorporation, however, appeared to be a more sensitive method in detecting cytotoxicity than MTT because the IC50 was lower in the former. In conclusion, all topical antimicrobials are cytotoxic to keratinocytes and fibroblast in their usual concentration. Because of their cytotoxicity it is suggested that one should use topical antimicrobials in a dilution of up to 1 : 1,000 of commonly used concentration for a short period only especially when applied directly on a skin graft or wounds without a protective barrier. Bacitracin or gentamicin appear to be less cytotoxic among all the antimicrobials tested.

MeSH Terms

Anti-Bacterial Agents
Bacitracin
Cell Membrane
Cell Proliferation
Chlorhexidine
Cytotoxins
DNA
Ethanol
Fibroblasts*
Fusidic Acid
Gentamicins
Humans*
Hydrogen Peroxide
Inhibitory Concentration 50
Keratinocytes*
Povidone-Iodine
Skin
Sulfadiazine
Thymidine
Transplants
Wound Healing
Wounds and Injuries
Anti-Bacterial Agents
Bacitracin
Chlorhexidine
Cytotoxins
DNA
Ethanol
Fusidic Acid
Gentamicins
Hydrogen Peroxide
Povidone-Iodine
Sulfadiazine
Thymidine