PITTSBURGH — Under rules approved Wednesday, the Allegheny County Health Department says doctors must now report all cases of a drug-resistant staph infection known as MRSA, not only cases involving people younger than 18 as was required previously.

The infection Methicillin-resistant Staphylococcus aureus is common in hospitals and health care settings, but also among school sports teams because it can be spread by contact with infected skin.

Health department director Dr. Bruce Dixon said the change comes because doctors are seeing more of the staph infections in adults.