It's often that people come home from the hospital with a cold or other illness.
But what can really fell them is taking too many anti-biotics because that can dampen the good bacteria that protects from the bad bacteria.
UT Health Science Center's Barbara Murray, M.D., is a specialist of infectious disease.
She agrees with the Centers for Disease Control: that the use of anti-biotics needs to be reigned in.
"So when you are on anti-biotics, the bacteria inside of you can mutate or pick up resistance genes from the other bacteria there and they then take over."
The Centers for Disease Control is so worried about anti-biotics allowing "superbugs" to bloom, they're grading threat levels of anti-biotics.
"I think that we use more than in northern Europe but we use less than in Mexico and countries where out-patient anti-biotics need a prescription to get them,"
Murray says hospitalized patients should insist that people entering their room wash their hands. She says catheters are also a source of germs leading to infectious disease because though they are sterile, they touch the skin, which is not.
"We have to balance the risk of not treating an infection versus the possible future risk
that may lead to more anti-biotic resistance," says Murray.