Dr. Charles Gerba has spent a lot of time in the bathroom. The microbiologist from the University of Arizona is the world's foremost authority on organisms that live in and near the commode. He has spent part of his professional life studying how droplets from the toilet bowl migrate to other areas of the bathroom. Once he used a strobe light to shoot a time-lapsed photograph of what happens when a person flushes the toilet. He found that droplets of water rocket out of the bowl with tremendous speed, each laden with invisible bacteria and viruses. The take-home: Stash that toothbrush in the medicine cabinet [source: Marston].
Still, dorm toilets are relatively clean compared to the dorm shower. The latter are oversized petri dishes. A study conducted by the Simmons College Center for Hygiene and Health in Home and Community found that shower floors were the most contaminated surface in college dormitories. The shower, with its moist, humid environment, had more than 40 times the number of bacteria than the toilet seat. Forty-three percent of the shower floors that researchers studied contained fecal bacteria, while 20 percent were contaminated with Streptococcus,a spherical bacterium that can cause infections such as strep throat and scarlet fever [source: PR Newswire].
Other microbes lurk in the shower, too. Mold is extremely prevalent and problematic for those suffering from allergies, asthma or other breathing ailments. Other fungi can cause athlete's foot, skin infections, nail infections, and jock itch [sources: Centers for Disease Control, Fox News, Cigna].
If you think public showers are a no-man's-land of pathogens, you don't want to know what's going on at the sink, specifically the faucets. Thousands of different types of germs rest on the handles of sink faucets, including methicillin-resistant Staphylococcus aureus (commonly known as MRSA). Even electronic, non-touch faucets are cesspools. A Johns Hopkins University study found that half of the samples obtained from electronic-eye faucets were contaminated with Legionella spp., which causes Legionnaires' disease. Researchers speculate that parts of the electronic faucet might trap the bacteria, allowing Legionella spp. to multiply, grow and seep into the water supply and ultimately onto, or into, your body [sources: PR Newswire, Men's Health].
Public restroom floors — including the one in your dormitory — are filthy, too. Gerba, aka Dr. Germ, says about 2 million bacteria live on every square inch of floor surface. That's about 200 times more than a sanitary surface. And here's a shocker for you ladies, the sanitary napkin disposal unit can brim with germs, too [source: ABC News].