An antibiotic-resistant "superbug" that infects healthy people keeps popping up in Calgary – and doctors fear the outbreak might be the start of a deadly nationwide epidemic, a CBC News investigation has learned.

MRSA, or methicillin-resistant Staphlycoccus aureus, normally thrives in hospitals, making sick people sicker – and doctors know which antibiotic will beat it.

But a more powerful strain of MRSA has been spreading among healthy people who have never been in hospital, first in the United States and now in Canada. Standard antibiotics don't seem to slow its ravages at all.

"Community MRSA, this particular strain, appears to be more virulent," Dr. John Conly, who heads the Department of Medicine at the University of Calgary, told the makers of a documentary that aired Wednesday on CBC-TV's The National.

"So, in the case of a boil, it becomes larger, more deep-seated. It may spread into the blood stream, develop into a large abscess. In the case of a pneumonia, which is the more worrisome, it continues to spread through the lungs unabated."

Man's lungs destroyed in 4 days

That's what happened to a young man early in the outbreak. His X-rays and a CT scan over four days showed how pneumonia ripped through his lungs, unchecked by the antibiotics. The MRSA destroyed his lungs from the inside and within four days of being admitted to hospital, he was dead.

"What happens is that the infection continues to progress because you're really not treating with anything," Conly said.

"You're basically giving something to which the bacteria are completely resistant."

He said it has quite serious consequences for not only the public but for the treating physicians, who need to scrap the usual antibiotics for alternatives.

MRSA initially mutated from a common bacteria called Staph aureus, which can cause infections if it gets into cuts or scrapes but is easily treated with antibiotics.

Calgary hit by 15 to 30 superbug cases a month

The Calgary cluster of cases – the first significant outbreak in Canada of the new Community-acquired MRSA – began to appear nearly a year ago.

Forty cases had appeared by October. Most but not all of the infections have been in street people, intravenous-drug users or prisoners.

Now Calgary physicians are seeing 15 to 30 cases a month, sparking fear that a superbug outbreak is poised to explode.

"There are other pockets that are starting to surface in Canada now so in fact this could be the beginnings of what they've been seeing in the United States," Conly said.

MRSA explodes among Chicago's children

In Chicago and dozens of other U.S. cities, MRSA was virtually unknown a decade ago, but now it's a growing threat.

Doctors at the University of Chicago hospitals have seen so many cases they are now experts in community-acquired MRSA.

When Dr. Robert Daum and his colleagues first detected a 25-fold increase in childhood cases in the mid-1990s, no one could believe it.

Daum, a professor of pediatrics at Chicago's Children's Hospital, says these days, two-thirds of the children coming in with staph aureus infections have the antibiotic-resistant strain.

"It's very clear we are in the middle of an MRSA epidemic now," Daum said.

"Both in our emergency room and our inpatient service, we are admitting patients by the flocks with this."

These children weren't weakened by other diseases, they were healthy.

Baby dies within 16 hours

Everly and Jim, a young Chicago couple, have experienced first-hand the deadly speed of the superbug.

One day last year, their 17½-month-old son Simon woke them at 6 a.m. with what Everly described as "incredibly strange primal scream."

They took the boy to a hospital emergency department, where he grew every more listless as hours passed and seemed to have trouble breathing.

When she felt his forehead and realized it had turned as cold as ice, she summoned a doctor who said Simon had to be immediately placed on an heart-and-lung machine as "his only chance" to live.

He was pronounced dead only 16 hours after the first scream. It was two months before they learned MRSA had killed their son.

Such an extreme outcome is very rare – but not unique.

"It was an emotional tsunami," said Everly, public health consultant. "As a public-health professional, I couldn't believe my son Simon had died from a bacteria, an infectious disease. And I thought no, we passed this era.

"I started to think about families 50, 100 years ago who actually had many, many kids on purpose because it was assumed you have at least one child die."

The quest to find the cure

The tricky bit is figuring out which drugs will work to treat MRSA – and the stakes are high. Before antibiotics, 90 per cent of people who got invasive staph infections died.

It takes precious time in a microbiology lab to learn exactly which antibiotic will kill a given bacteria infecting a patient.

Everly and Jim agonize daily over how their healthy child became infected – and why he died so fast. Everly believes society has to kick its antibiotic habit or face a hard truth:

"The overprescription of antibiotics, and the use of antibiotics in animal feed, and use of antibiotics in all the cleaning products have created an environment whereby the weaker bacteria are dying off, leaving the stronger bacteria to be even stronger," she said.

Daum, who's tracked the growing epidemic in Chicago children for a decade, believes Staph aureus will always find a way to outwit antibiotics.

"Staph is a very complicated pathogen ... because it has multiple systems for doing the same thing and it's not going to cough up its secrets easily to a vaccine approach.

"So this is going to be a difficult vaccine to make."