Topics in Dentistry



The air in bathrooms is easily contaminated by flushing the toilet, so the best place to store your toothbrush is in a drawer or medicine cabinet—or outside of the bathroom altogether.

Dr. Germ – December 26, 2007 – by Charles John Palenik

Charles P. Gerba, PhD, professor of environmental microbiology at the University of Arizona, is an expert on drinking water quality and pathogens in the environment. He has published more than 400 scientific articles and nine books. He developed the first method to test water for the presence of cryptosporidium, a parasite responsible for sporadic outbreaks of diarrhea. But it is his interest in household and workplace microbes that has brought him greater recognition and the moniker—Dr. Germ. For Dr. Gerba, it all started after flushing a toilet in Houston, Texas.

While a postdoctoral fellow at Baylor University, Dr. Gerba was asked by his adviser to observe a toilet flushing and to note the aerosols generated. Dr. Gerba soon devised a method for studying the distribution patterns of the droplets emitted, and called it a commodograph. Analyses of emissions indicated the presence of high numbers of bacteria and viruses. Microorganisms form biofilms on porcelain surfaces with gradual elution after each flush. The study indicated the presence of fecal organisms on a variety of bathroom surfaces. Air currents moved aerosolized microbes to surrounding areas unless they were blocked by a door. Flushing with the lid down also reduced microbial spread. Dr. Gerba advocated placing toothbrushes within drawers or in the medicine cabinet to prevent contamination.