Skin fungal biocontamination and the skin hydrogel pad test

Previous observations have revealed that environmental nondermatophyte molds (NDM) can grow inside specific hydrogel pads (LaserAid). Some of these NDM might be responsible for superficial and invasive mycoses as well as for allergic respiratory and cutaneous disorders. The load of NDM propagules in the environment is considered to be an important risk factor for all these diseases. It is postulated that the quantification of the responsible fungi deposited at the skin surface may be an indicator of a recent exposure to environmental fungi. The aim of the present study was to assess using the LaserAid hydrogel pads, the density of living NDM adhering to the skin surface of healthy subjects. Sterile hydrogel pads were applied in a repeat procedure onto the normal-looking skin of the palms and face of 35 healthcare workers who were active in low exposure areas. Similar samplings were performed after washing the skin with a regular skin cleanser, or after applying an alcohol solution or a povidone iodine solution. As controls, 20 sterile pads were exposed for a few minutes to ambient air of the laboratory without any contact with the skin. Each of these samples was stored for 2 weeks at room temperature in a clean protected environment. After that period, visual inspection of the pads was followed by microscopic examination of PAS-stained 6 microm-thick sections. In addition, mycological cultures were performed from pieces of the pads deposited onto Sabouraud agar plates. While 19/20 air-exposed samples were not contaminated by environmental air-borne fungi, 61/70 of the initial skin samplings and 6/70 of the repeat skin samplings showed foci of fungal colonization confirmed by microscopic examination. No specific differences were disclosed between the face and palm samplings. Cultures revealed the presence of NDM in the majority (64/67) of the colonized pads, and a few Candida albicans contaminations (3/67) were also disclosed. The cleansing with a non-antimicrobial product as well as disinfecting procedures performed before sampling markedly decreased the mycoflora without, however, clearing the skin of NDM and yeasts. In conclusion, the hydrogel pad procedure brings information about potential environmental skin contamination by NDM and commensal yeasts. The regular cleansing and disinfecting procedures do not eradicate these fungi from the skin surface.