Antimicrobial effect of acidified nitrite on dermatophyte fungi, Candida and bacterial skin pathogens

Aims: Nitric oxide is generated from sweat nitrite in the acidic environmen t of the skin surface and is thought to contribute to protection against in fection. This study examined the sensitivity of Trichophyton mentagrophytes , T. rubrum, Candida albicans, Streptococcus pyrogenes, Staphylococcus aure us and Propionibacterium acnes to acidified nitrite. Methods and Results: Organisms were cultured in varying concentrations of n itrite and pH for different lengths of time, before being transferred to re covery medium. With the exception of Strep. pyogenes, addition of nitrite i ncreased the antimicrobial activity of acid solutions against all organisms tested. The rank order of sensitivity was: C. albicans < T. rubrum < T. me ntagrophytes < Staph. aureus < P. acnes, with P. acnes being most sensitive . Conclusions: This work has shown that acidified nitrite is microbiocidal to common cutaneous pathogens. The concentrations of nitrite required to kill pathogenic fungi and bacteria in in vitro assays were higher than the conc entrations of nitrite measured in sweat. However, additional co-factors in vivo and in sweat may potentiate the effect of acidified nitrite. Significance and impact of the Study: Pharmacological preparations of acidi fied nitrite are novel antimicrobial agents. These data suggest skin organi sms which may be sensitive to this treatment.