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Optimization of an infected shoe model for the evaluation of an ultraviolet shoe sanitizer device
Mahmoud A Ghannoum1, Nancy Isham, Lisa Long
1Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106, USA. mahmoud.ghannoum@case.edu
Background:
Onychomycosis and tinea pedis (athlete's foot) are infections of the nails and skin caused by pathogenic fungi collectively known as dermatophytes. These infections are difficult to treat, and patients often relapse; it is thought that a patient's footwear becomes infected with these fungal organisms and, thus, is an important reservoir for reinfection. Therefore, it is important to find an effective means for killing the dermatophytes that may have colonized the inner surface of the shoes of patients with superficial fungal infections. In this study, we developed an in vitro model for culturing dermatophytes in footwear and used this model to evaluate the effectiveness of a commercial ultraviolet shoe sanitizer in eradicating the fungal elements residing in shoes.
Methods:
Leather and athletic shoes (24 pairs) were inoculated with either Trichophyton rubrum or Trichophyton mentagrophytes (10(7) colony-forming units/mL) strains and were placed at 35°C for 4 to 5 days. Next, we compared the ability of swabbing versus scraping to collect microorganisms from infected shoes. Following the optimized method, shoes were infected and were irradiated with one to three cycles of radiation. The inner surfaces of the shoes were swabbed or scraped, and the specimens were cultured for dermatophyte colony-forming units.
Results:
Leather and canvas shoes were infected to the same extent. Moreover, scraping with a scalpel was overall more effective than was swabbing with a cotton-tipped applicator in recovering viable fungal elements. Irradiation of shoes with one, two, or three cycles resulted in reduction of fungal colonization to the same extent.
Conclusions:
The developed infected shoe model is useful for assessing the effectiveness of ultraviolet shoe sanitizers. Also, ultraviolet treatment of shoes with a commercial ultraviolet C sanitizing device was effective in reducing the fungal burden in shoes. These findings have implications regarding breaking foot infection cycles.
Insights
Ultraviolet (UV) shoe sanitizers effectively reduce fungal infections like athlete's foot by eliminating dermatophytes from footwear. This UV treatment helps break the cycle of reinfection for individuals suffering from persistent fungal foot conditions.
Area of Science:
- Mycology
- Dermatology
- Infectious Diseases
Background:
- Onychomycosis and tinea pedis are common fungal infections caused by dermatophytes.
- Footwear serves as a reservoir for fungal reinfection, complicating treatment.
- Effective methods to eliminate fungi from shoes are crucial for managing recurrent foot infections.
Purpose of the Study:
- To develop an in vitro model for culturing dermatophytes in footwear.
- To evaluate the efficacy of a commercial ultraviolet (UV) shoe sanitizer against fungi in shoes.
Main Methods:
- 24 pairs of leather and athletic shoes were inoculated with Trichophyton rubrum or Trichophyton mentagrophytes.
- An optimized method involving scraping was used to collect microorganisms post-UV irradiation.
- Shoes were irradiated with 1-3 cycles of UV light and fungal elements were cultured.
Main Results:
- Both leather and canvas shoes showed similar infection levels.
- Scraping was more effective than swabbing for recovering viable fungal elements.
- UV irradiation, regardless of the number of cycles (1-3), significantly reduced fungal colonization.
Conclusions:
- The developed infected shoe model is a valuable tool for testing UV shoe sanitizers.
- Commercial UV-C devices effectively reduce the fungal burden in shoes.
- UV shoe sanitization shows promise in breaking the cycle of foot fungal infections.
