Drug-Resistant Infections on the Rise By Kathleen Doheny, HealthDay Reporter    HealthDayNews -- A bacterium that is becoming more resistant to first-line antibiotics is causing record numbers of skin infections in otherwise healthy children, according to a new study.    The bacterium, called methicillin-resistant Staphylococcus aureus (MRSA), is also emerging as a cause of pneumonia, which can be fatal...