MRSA stands for "methicillin-resistant Staphylococcus ("staph") aureus," a type of antibiotic-resistant bacteria. Most strains of staph can be easily treated with a range of antibiotics, but there are only a few drugs that can beat MRSA. This is partly because of overuse of antibiotics, but it's also a natural response of bacteria: As we create new drugs, they figure out ways around them. Unfortunately, it's hard to know how your toddler was exposed -- it can be picked up from common surfaces and other people, too. Still, there are simple steps you can take to protect your family: Keep clean. Use plenty of regular soap and water when you're at home, and carry alcohol-based hand sanitizer to use when you're out. Avoid sharing towels or other personal items (it lowers the chance of spreading bacteria). Treat skin irritations quickly. If you don't notice improvement within a couple days, call your doctor. And as always, keep cuts covered.

Pediatrician Claire McCarthy, M.D., is medical director of the Martha Eliot Health Center in Boston. Send her your health questions at Meet the Mom Squad.