Two students in North Hills School District have contracted methicillin-resistant staphylococcus aureus, or MRSA, according to a letter posted on the district's Web site.

The students attend North Hills Junior High School and North Hills Senior High, and both have been treated by their doctors, according to the letter.

MRSA is a bacterial infection that can cause redness, boils, swelling or areas that are warm to the touch and painful. The infection is resistant to antibiotics and is best prevented through diligent personal hygiene, such as hand-washing, showers and laundry.

Because of MRSA infections in other area school districts, North Hills had posted MRSA information on its Web site about a month ago and had already adjusted its cleaning procedures, said Tina Vojtko, communications coordinator for the district.