Many of the drugs that control inflammatory forms of arthritis work by suppressing an overactive immune system, which attacks and damages joints and other organs. That’s a mixed blessing if you depend on these medications to function. On the one hand, these medications relieve pain and inflammation, and curb disease progression, but on the other, they can leave you vulnerable to infections from germs, including bacteria and viruses.

If you’re taking one of these medications – disease modifying antirheumatic drugs (DMARDs) or  biologics – you need to give yourself the upper hand against germs. It’s prudent to take a few precautions when you’re engaged in activities that bring you into close contact with the kinds of bugs, called pathogens, that are most likely to make you sick.

Here’s what science has to say about what works and what doesn’t when it comes to steering clear of dangerous microbes.

Myth No. 1: You can sterilize a kitchen sponge by zapping it in the microwave. 

Not if you’re relying on radiation alone to do the job. According to Philip Tierno, PhD, director of microbiology and immunology at New York University Langone Medical Center and author of the book The Secret Life of Germs: What They Are, Why We Need Them, and How We Can Protect Ourselves Against Them (Atria, 2004), microwaves are unreliable germ killers because the appliances tend to have dead spots where their radiation doesn’t reach. Even if you use a turntable, it’s possible that bacteria and viruses lurking in a kitchen sponge, which is typically one of the most germ-laden surfaces in the entire house, could survive.

But Tierno says there is a more reliable way to sterilize a kitchen sponge using a microwave: Immerse the sponge in a microwave-safe dish of water, and zap for four minutes on high. The microwave will heat the water to 150 degrees F, a temperature that’s hot enough to kill any lurking nasties. (Be sure to let the sponge cool before you pick it up.) Alternatively, you can soak the sponge for a few minutes in a solution of 2-1/2 tablespoons of bleach (the volume of a shot glass) mixed with four cups of water, or pop the sponge into your dishwasher if it has a “sanitize” setting.

Myth No. 2: As long as you’ve sterilized your kitchen sponge, it’s okay to use it to wipe down the counters.        

If you use the dish sponge to wipe down counters, your kitchen probably only looks clean, says Elizabeth Scott, PhD, a microbiologist who is the co-director of the Center for Hygiene and Health in the Home and the Community at Simmons College in Boston, Mass.           

“In reality, what you’ve done (and I’ve tested this), is you end up spreading bacteria around your kitchen,” Scott says. She recommends reserving the sponge for dirty dishes and using recycled paper towels to clean up food spills on the counters. Clean up surface food particles and grease with a paper towel. Then throw it away. Follow the use of a cleaner with a disinfectant. 

Myth No. 3: It doesn’t do any good to use antimicrobial agents in soaps and cleaners; odds are that these agents won’t kill the germs, but they could end up making the germs stronger and your immune system weaker. 

The idea that you can clean yourself sick is called the hygiene hypothesis, and while there is some evidence to suggest that immune system malfunctions, such as allergies, asthma and eczema, may be on the rise because we are not exposed to as many germs as we used to be during childhood, some experts see holes in this logic.

“My informed feeling based on the work that I’ve looked at is that [the rise in some diseases is] not because we’re too clean,” says Scott. “If you take it to its logical conclusion, if being too clean is compromising our health, let’s look at a community in Zimbabwe and look at what’s happening there,” Scott says. “That’s a community that’s definitely not able to be too clean, they’re experiencing a huge onslaught of microbial pathogens all the time, and they’re very, very sick.”

Theories like this one are useful for research but in everyday life, “Certainly, if you’re already immunocompromised,” Scott says, “you cannot be too clean.”

Still, Scott says it is smart to be judicious about using disinfectants. She advocates what she calls a targeted hygiene practice – using antimicrobial chemicals only in areas that are most likely to harbor germs that may pose a threat to health, like the kitchen sink or on frequently touched surfaces like remote controls, keyboards, or faucets.

Scott says you probably don’t need to use cleaners with germicidal ingredients on places like windows and floors, which tend to be relatively free of bacteria and viruses. The only time you might want to disinfect a floor, Scott says, is if you have a little one who is crawling, and there’s a sick person or pet in the house that has vomited or defecated.

Myth No. 4: You are likely to catch a cold from someone who sneezes two feet away from you in an office or a plane.

It’s certainly possible, Scott says, but it’s not likely. Based on her studies of how people come into contact with germs, she says you are more likely get sick after picking up a virus on your hands and then touching your face. “We, all of us, touch our faces so many times a day that we inoculate our eyes, in particular, and then the virus moves down into the nose,” Scott says.

Tear ducts are particularly vulnerable. They don’t have as many defenses against germs as your mouth or nose, Scott says, so you’re most likely to get sick by touching a contaminated surface and then rubbing your eyes.

Myth No. 5: You can get a dangerous infection from Methicillin-resistant Staphylococcus aureus (MRSA) if you go to the hospital.

Yes, that's true, but that’s not the only place MRSA bacteria, which cause infections that are resistant to many kinds of antibiotics, are lurking these days.

Scott has been surveying homes and college dorms for pathogens, and she reports that MRSA has most definitely moved into the community. MRSA seems to be especially prevalent in gyms, locker rooms and bathrooms, and many of the earliest community-acquired cases have been among men engaged in contact sports.

Scott says that she has found it in homes on hand contact surfaces such as bathtub faucets. And unlike many kinds of bacteria, which can’t survive for long after they are exposed to air, MRSA can survive in dry environments.

One particularly startling finding from her work: Scott says she was eight times more likely to find MRSA if there was a cat in the home. That study was published in the American Journal of Infection Control. 

“Pets are wonderful companion animals,” Scott says, “But people just need to be aware that pets do excrete and carry pathogens that we can pick up.”

Scott says kids, especially, should be coached to wash their hands immediately after handling a pet. Pet equipment, such as cages and bowls, should be washed and disinfected regularly, but they should never be washed in the kitchen sink.