Microbiology of sunscreens in use

The microbial contamination of the skin through polluted water or skin care products can cause infections and exacerbations of other dermatological manifestations. The degree of contamination of suntan products (STP) is unknown, but the pattern of use (used directly on the skin, kept in the sun and other warm places) is thought to facilitate the growth of microbes. The aim of this study is to establish the level of contamination in STPs and its relationship to possible adverse skin reactions. Cultures of bacteria and yeast from STPs in use on beaches were investigated. Contamination was found in 70 of 124 STPs tested, with Candida species (Candida Spp.) found most often (57/124) followed by Gram-positive bacteria (34/124), while only two containers were contaminated by Gram-negative bacteria. Multiple contaminants were found in 24 of 124 STPs. No significant association was found to self- reported skin problems, age of STP, size of container, or shared use. Although a high level of contamination was found, particularly with Candida, contamination was not significantly associated with self-reported skin problems following STP use. Therefore, it is unlikely to influence the pattern of use of STPs. It is speculated that susceptible individuals may have an increased risk of adverse events due to the high level of contamination.