Microbiological Assessment of the Different Hand Drying Methods and Washroom Environment Cross-Contamination

Abstract

Proper hand drying is a fundamental part of the hand hygiene process looking at optimizing the elimination of potentially pathogenic microbes. This research compared the effectiveness of three different hand drying methods—paper towels, the use of warm air dryers in stationary hands position, and the use of air drying while hand rubbing—and their potential for cross-contamination of other users and the surrounding environment. One hundred sixty samples were collected from finger pads and palms, before and after drying. The outlet of the air dryers, air current emitted from the air dryers, and washroom environment air were also tested. The study reported that paper towels were more successful in eliminating bacteria and lead to less contamination to the washroom environment compared to the air dryers. The average number of bacteria obtained from volunteers using hand air dryer while hand rubbing was significantly higher than drying with air dryer while holding hands stationary. Plates exposed to the turned-off dryer for 5 minutes gave an average of only 25 colonies/plate, while plates exposed to the air outlet of the turned-on warm air dryers provided 292 colonies/plate. Placing Petri dishes at least one meter away from the dryer in the washroom for 30 minutes gave 72.5 colonies/plate. The current research also documented frequent contamination of public washroom environments and showed dissemination of potential pathogens, including Escherichia coli (E. coli), Klebsiella species, Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), and coagulase-negative Staphylococci. Over 70.0% of Staphylococci were resistant to at least three antibiotics and 50.0% revealed coresistance to at least four antibiotics including penicillin, erythromycin, clindamycin, and co-trimoxazole. The method of hand drying may serve as a risk factor of cross-contamination from users to the environment and subsequent users and as reservoirs of drug-resistant bacteria in public washrooms.