A dangerous infection that used to affect mostly the chronically ill and the frailest of patients has gone on the attack against otherwise healthy people and is now widespread in local communities, medical professionals say.

"MRSA used to be something you would just see in a hospital or a health care setting," said Lynda Caine, director of infection control at Elliot Hospital in Manchester.

But a different strain of the MRSA staph infection, with which a Londonderry student athlete was recently diagnosed, is spreading through schools, health clubs and other community settings in Southern New Hampshire and the Merrimack Valley.

Officials at local hospitals say they are seeing a lot of new cases.

"I hate to use the word epidemic," said Connie Gagnon, the director of education and infection prevention coordinator at Merrimack Valley Hospital in Haverhill, Mass. "But we are seeing an increase in patients, and it is a large increase."

Dr. Venugopal Saddi of Caritas Holy Family Hospital in Methuen, Mass., agreed that the situation hasn't reached epidemic levels. But he also said he has been seeing "increased incidences of infection from community-acquired MRSA."

People shouldn't panic, he said, but they do need to be aware that MRSA has changed its favorite targets and is picking up intensity.

Several New Hampshire schools have reported cases of MRSA, typically connected to school athletics. Last year, eight football players at Nashua North High and one at Nashua South were diagnosed with MRSA, and 15 players at Pinkerton Academy in Derry had staph infections. Any setting where people congregate and share items like towels, razors or clothing provides an opportunity to contract MRSA.

"We've had several cases over the years," said Anna Davis, head nurse at Pinkerton Academy. "It's not an uncommon thing, but it is something we didn't see years ago."

Pinkerton coaches drill the athletes on hygiene, including washing uniforms and gear in hot water and soap, she said. They also remind the students to bandage any cuts.

Anything from a paper cut to a bruise provides MRSA with a path to cause a skin infection, Caine said.

"Clean hands, clean things — it's as simple as that," she said. "Wash your hands before and after. If you're using disposables, toss them; if they're reusables, clean them and sometimes disinfect them."

MRSA — which stands for methicillin-resistant Staphylococcus aureus — mostly causes skin infections. But the germ can be life-threatening if it gets into the bloodstream, lungs or organs. About 95,000 serious infections and 20,000 deaths due to drug-resistant staph bacteria occur in the U.S. each year.

The trend toward the prevalence of community-acquired MRSA actually started in 2000, Saddi said. Usually, the same patient has recurring MRSA infections, he said, so education is important to prevent the spread of infection at home.

Typical MRSA patients in the past included people who had been in long-term health care facilities, but that's not the typical MRSA case today, Gagnon said.

Randy Smith, director of infection prevention at Parkland Medical Center in Derry, said the typical case is a patient who comes into the emergency room with an abscess.

"And it'll turn out to be MRSA," he said. The infection usually presents as a boil or pimple or other type of skin infection. Parkland doctors now see more people infected with the community-acquired MRSA strain than with the hospital strain.

Any type of staph infection can be serious, Smith said. Community-acquired MRSA is also "not something to fool around with. If it hasn't gone too far, the patients can usually be treated," he said, but the results vary.

"If a person has a good immune system," and is free of other diseases, the doctors can usually control MRSA with antibiotics, he said.

The more serious MRSA infections involve the urinary tract, the bloodstream and wounds, because these infections pose the danger of sepsis. MRSA can also cause pneumonia.

"And it's a bad pneumonia," Smith said.

MRSA is resistant to most of the drugs that doctors typically use to treat staph infections.

Vancomycin is the antibiotic that has proven most effective against it. Only four or five cases worldwide of Vancomycin-resistant MRSA have been reported, Smith said, so to date, the infection has not developed into a superbug.

Parkland Medical Center was recognized last year by the Institute for Health Improvements for its efforts to reduce hospital staph infections.

All of the area hospitals surveyed have implemented "contact precautions" for patients with MRSA or suspected MRSA. Staff members wear gloves and gowns when caring for patients, and some patients are screened for MRSA when they are admitted if they belong to one of the risk populations.

"This is nothing new for us," Caine said. "It's new for the public, and it's scaring people."

The Associated Press contributed to this report.