At Chichester High School, a single student's skin infection prompted the superintendent to cancel after-school activities and order the high school scrubbed with bleach overnight. Four hundred students - about one-third of the school - stayed home yesterday.
Also in Delaware County, a student's infection led officials to close Indian Lane Elementary near Media yesterday, locking the doors while janitors attacked buildings with mops and disinfectants.
Across the country, dozens of reported cases suggested an epidemic of an infection few had heard much about - MRSA, for methicillin-resistant Staphylococcus aureus.
Yet scientists say the MRSA problem is no worse now than it was last week, or even last year.
People are on high alert to the threat of MRSA after the infection killed a Virginia high school student Monday and news outlets reported a rise in a new strain of the bacteria two days later.
The disease usually infects through a skin lesion and is only rarely fatal. Doctors say the public may be misled by the term antibiotic resistant. MRSA is a staph bacterium that evolved a resistance to penicillin, its synthetic counterpart methicillin, and several related antibiotics. But it can be cured with many other antibiotics, so most cases clear up with the right treatment.
"It's an inappropriate panic," said Susan Coffin, director of infection prevention and control at Children's Hospital of Philadelphia. "I'm getting letters from people saying their children are told not to return to school" after an infection.
Scientists say MRSA represents a long-term problem rather than an immediate threat.
In recent years, a number of isolated cases and outbreaks have cropped up among professional football teams and high school athletes, said Neil Fishman, an infectious-disease specialist at the University of Pennsylvania Medical Center.
Usually the infection is transmitted from skin-to-skin contact, abrasions, and possibly the sharing of razors, towels and soap. The infections typically fall under the radar, the students get treatment, and nobody worries.
That all changed this week.
On the heels of the Virginia death, the Centers for Disease Control and Prevention issued a report that said a relatively new strain of MRSA accounted for about 14 percent of the more dangerous invasive cases.
On Wednesday, the Washington Post reported that annual MRSA deaths from all strains now outnumber deaths from AIDS.
That's misleading, Fishman said, because most of those MRSA deaths happen to terminally ill or very frail people in hospitals where it is not always clear the death was really due to MRSA. And many other diseases kill more people than AIDS.
Ed Cardow, the Chichester school board vice president, said the superintendent contacted the state Health Department and the CDC immediately after a MRSA case was reported. Cardow said the superintendent then followed their recommendations to clean overnight with a bleach and water solution and reopen in the morning.
"We jumped on it as fast as we could," Cardow said.
In New Jersey, Point Pleasant Boro High School was being disinfected by Aramark cleaning crews with hospital-grade sanitizing equipment after one student was found to have MRSA.
The middle and elementary schools will be cleaned this weekend.
Yet experts agreed that disinfecting school buildings is unlikely to help.
"In general we do not recommend closing schools and cleaning them," said Arjun Srinivasan, a medical epidemiologist at the CDC. "It's not necessary to go to such extremes to prevent the spread of MRSA. The transmission is predominantly through skin-to-skin contact or by a surface that previously contacted an open lesion."
Experts are not sure how long the bug can live off the body, but nearly every case is traced to skin-to-skin contact or the sharing of locker-room items.
The disease often spreads through football teams because players not only contact one another but suffer abrasions from the sport. Five cases were recently reported among football players at Harriton High School, in Lower Merion School District.
Attempts to sterilize rooms or buildings could lead to a false sense of security, Fishman said.
"It's impossible to sterilize the environment; it will constantly become recolonized with a variety of organisms [including MRSA]," he said. "The critical factors of transmission are related to personal hygiene."
The cleanup at Indian Lane Elementary School, where classes were canceled, was initiated by the district's superintendent, Denise Kerr.
"I knew once we told parents we had a MRSA case at the elementary level we would have a tremendous amount of concern, and the best way would be take extra time to clean the building," she said. "The feedback from parents was very positive."
Fishman said the newer strain, sometimes called the community-associated, or CA, strain, is actually curable with a wider range of antibiotics than the older, hospital-associated variety, but it tends to cause more invasive skin infections.
What's interesting about the CA strain is that it appears to be the first antibiotic-resistant bacterium to have originated outside of hospitals, said Stuart Levy, professor of medicine and microbiology at Tufts University Medical School.
Today both strains are intermingled, he said, so you can get the community-associated bug in a hospital or the hospital-associated bug somewhere else.
Experts worry that the overuse of antibiotics has led to an environment that could breed still more dangerous infectious agents. Antibiotics leach into the environment not only through medicine but through their use in cattle and chicken feed.
And scientists are turning up things far scarier than MRSA.
"We're starting to see more infections with organisms that aren't susceptible to any antibiotics," Fishman said. One, called acinetobacter, is infecting troops wounded in Iraq.
"I do think we are facing a national crisis of antibiotic resistance," he said. "But MRSA represents just the tip of the iceberg."
The Facts on a Staph Infection
Researchers determined this week that the most serious infections from
a specific, drug-resistant staph bacterium known as MRSA were more common than had been thought.
A number of school districts then reported some students were infected.
Question: What is staph?
Answer: Staphylococcus aureus is a group of generally harmless bacteria. They typically are present in at least 25 percent of
the American population, usually on the skin or in the nose.
Q: Do staph bacteria cause infections?
A: Sometimes they do. They are among the most common causes of minor skin infections (such as pimples and boils) in the United States. Occasionally the infections are serious - such as at surgical wounds or in the bloodstream.
Q: How are they treated?
A: Minor staph infections
do not call for antibiotics; antibacterials or antimicrobials do the job. Serious infections require drugs - the class known as antibiotics.
Q: What is MRSA?
A: About 1 percent of the population carries staph bacteria that have developed resistance to certain antibiotics. Like other staph, methicillin-resistant Staphylococcus aureus, or MRSA, often lives in the nose, throat and skin without causing infection.
But if it gets into the body, typically through a cut or scrape, it can cause potentially serious infections.
Q: What are symptoms of an MRSA infection?
A: MRSA should be suspected in skin or soft-tissue infections that are swollen, inflamed and painful. In the beginning, such infections might resemble a pimple or boil; many are initially mistaken for spider bites. If the infection becomes invasive, potentially serious symptoms can include fever, chills, and shortness of breath. An MRSA infection can be confirmed only through a skin or blood culture, and requires treatment with several antibiotics.
Q: How is it transmitted?
A: MRSA is most often spread by skin-to-skin contact, touching a contaminated surface, or through the sharing of personal items such as towels and razors.
Q: How can MRSA be prevented?
A: Vigorous and frequent hand-washing is the most effective way to stop MRSA transmission. Cuts and scrapes should be kept clean and covered with a bandage until healed. Health experts also discourage the sharing
of personal items.
Q: How about antibacterials?
A: It is believed that the widespread use of antibacterials actually has played a significant role in the development and spread of drug-resistant bacteria. For that reason, they discourage the use of antibacterials except in situations (hospitals, for example) where the risk is especially high.
For detailed information about MRSA, its treatment and spread, go to http://go.philly.com/health
Contact staff writer Faye Flam
at 215-854-4977 or firstname.lastname@example.org.
Staff writers Lini S. Kadaba, Ed Colimore, Martha Woodall and Kathleen Brady Shea contributed to this article.