Freedom High School in Oakley has one confirmed case and another that is suspected. Northgate High School in Walnut Creek announced a confirmed case Wednesday.
The "superbug," known as methicillin-resistant Staphylococcus aureus, or MRSA, garnered widespread national attention this month after the Centers for Disease Control and Prevention released a study revealing that it now kills more Americans than AIDS.
In 2005, an estimated 94,000 Americans became seriously ill from MRSA and nearly 19,000 died. That is compared with 17,000 who died of AIDS.
The study came out about the same time that news broke of a Virginia High School student who died from the infection.
Bay Area health experts advised parents Wednesday not to panic, however, noting that the infection does not cause problems for most people.
Staphylococcus aureus, or staph, is a common germ that many people carry in their nasal passage, under their fingernails or on their skin.
MRSA is a form of staph bacteria that has developed resistance to common antibiotics. It can be treated with other drugs, however.
The germ is spread primarily by direct skin-to-skin human contact or contact with drainage from an infected wound. It is not spread through the air, but it occasionally may spread through contact with contaminated surfaces or items.
Northgate High School Prinicipal Martha Riley alerted parents and staff about an MRSA case at the school Wednesday evening through an automated phone calling system.
The student, whose name was not revealed, is a football player at Northgate, said Greg Rolen, the district's lawyer.
The boy got a cut on his arm during a football game or practice, Rolen said. The wound later became infected.
The school nurse examined him and sent him to the hospital. He was treated with the drug Septra starting Friday and cleared to return to school Wednesday, according to a letter sent to parents.
The school has disinfected the locker room, sports equipment, the student's classrooms and other areas where the student may have been with a disinfectant ammonia used to combat staph infection, Riley said.
"All classes and activities will continue as planned," she said.
To prevent spread of the bacteria, health officials advise people to wash their hands carefully with soap and water, keep fingernails clean and clipped short, avoid contact with other people's wounds and avoid sharing such personal items as razors, jewelry, towels and soap.
"What you want to do is make sure people don't panic and don't become overly alarmed -- that's the first thing I worry about," Riley said.
At Freedom, parents have flooded the school with hundreds of calls in the past week, tying up phone lines for hours in an attempt to learn more about MRSA and what the school is doing to protect students.
Freedom officials revealed Wednesday that a second student suspected of having MRSA had the diagnosis confirmed by laboratory results. Test results are pending for another student.
Both cases came to school officials' attention within the past week.
One teen reportedly had scratched some mosquito bites that had become infected, said Principal Eric Volta. She tested positive for MRSA.
The girl's mother decided to seek medical attention after Freedom High School used its automated phone system to let parents know about a suspected MRSA case involving a 14-year-old who had abscesses on her knee.
School officials did not say whether the two girls are friends or whether they come into close contact on campus.
Both students have received clearance to return to school. Custodians sanitized every classroom last week and added more soap dispensers in bathrooms.
"You know what the good thing about all this is?" Volta said. "Now kids are washing their hands."
Staff writer Shirley Dang contributed to this story. Reach Theresa Harrington at 925-945-4764 or email@example.com. Reach Rowena Coestee at 925-779-7141 or firstname.lastname@example.org.