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The worktops in both chemical and microbiological laboratories are the surfaces most vulnerable to damage and exposure to contamination by indoor pollutants. The rate at which particles are deposited on indoor surfaces is an important parameter to determine human exposure to airborne biological particles. In contrast to what has been established for inorganic pollutants, no limit has been set by law for microbial contamination in indoor air. To our knowledge, a comparative study on the effect of surfaces on the deposition of microbes has not been carried out. An evaluation of the microbial contamination of worktop materials could be of crucial importance, both for safety reasons and for the reliability of tests and experiments that need to be carried out in non-contaminated environments. The aim of this study was to evaluate the overall microbial contamination (fungi, mesophilic and psychrophilic bacteria, staphylococci) on six widely used worktop materials in laboratories (glass, stainless steel, fine porcelain stoneware, post-forming laminate, high-performing laminate and enamel steel) and to correlate it with the characteristics of the surfaces. After cleaning, the kinetics of microbial re-contamination were also evaluated for all surfaces.

Surgical hand disinfection (with an alcohol-based hand rub) and surgical handwash (with an antiseptic-based liquid soap) are accepted measures to reduce the risk for surgical site infections. The new European Standards allow a comparison of their antimicrobial efficacy. The bactericidal activity of surgical hand rubs [Sterillium and Softaman, (active ingredient=alcohols)] and handwashes [Derman plus (triclosan), Hibiscrub (chlorhexidine) and Betadine (PVP-iodine)] was tested according to the prEN 12054 suspension test using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus hirae, and to prEN 12791 for the effect on resident skin flora in comparison with 1-propanol, 60% (v/v). All five products achieved a reduction of test bacteria within 3 min of >10(5)-fold so fulfilling prEN 12054. However, only Hibiscrub, Sterillium and Softa Man met the requirements of prEN 12791, giving a mean reduction of resident micro-organisms (immediate and sustained effect) which was not significantly lower than the reference alcohol (P>0.1; Wilcoxon matched-pairs signed-rank test). Sterillium was significantly more effective than the reference alcohol (immediate and sustained affect). Products for surgical hand disinfection may have equal antimicrobial activity in suspension tests but show large differences under practical conditions. Healthcare workers should not rely on results from suspension tests when deciding on a product for surgical hand disinfection.