By Anita Manning, USA TODAY

On Christmas night, 14-month-old Bryce Smith came down with pneumonia caused by a drug-resistant staph infection called MRSA. His father, Scott Smith, says Bryce's pediatrician told him and his wife, Katie, that the baby had a cold and that they shouldn't worry. 

By the time they took Bryce to the hospital a week later, the infection had eaten a hole in his lung, and doctors warned the parents that they were not certain he'd live.

Bryce, back at home and healthy again after 55 days in the hospital, is one of thousands of children and adults who have been infected by MRSA, or methicillin-resistant Staphylococcus aureus, a bug once found only in hospitals or nursing homes. They are victims of a dangerous newer strain of MRSA that is raging across the country, spreading through communities.

It is causing infections from abscesses to deadly blood poisoning, bone infections and pneumonia, often in the young and the fit, including professional football players, high school athletes and previously healthy children.

Whether it spread from the hospital into the community or developed as a separate strain outside the hospital is a mystery, says John McGowan, professor of epidemiology at Emory University. But recent genome studies suggest the MRSA strain circulating in the community is significantly different from the strains that are typically found in hospitals.

"There are differences in the sequence of the community strain that may make it more virulent, more able to affect people with (healthy immune systems), and with biological differences that make it spread readily," he says.

MRSA has become so common that in many hospitals more than half of all staph infections tested are drug-resistant. That's changing the way doctors treat these common infections.

"When a patient comes in with a staph infection, we assume it's resistant until proven otherwise," says pediatrician Sheldon Kaplan of Texas Children's Hospital in Houston, where MRSA rates have gone from 33% of all staph tested in 2000 to 75%.

Drug-resistant bugs, including MRSA and several others that are emerging in hospitals, are more difficult to treat, requiring stronger antibiotics that are more costly and in some cases have to be given intravenously.

Few new drugs on the way

Few major pharmaceutical companies have new medicines in the pipeline that target the drug-resistant organisms, says George Talbot of the Infectious Diseases Society of America's task force on anti-microbial availability.

"In a number of these companies, there were active decisions taken that antibiotic research was not going to be profitable enough to meet their obligation to shareholders," says Talbot, an infectious-disease specialist and consultant to drug companies. "So they decided to go for drugs that would be taken for a lifetime — drugs for diabetes or high blood pressure — rather than drugs to be taken for a week."

Jumping into the breach are smaller biotech companies that are doing the basic research to identify promising new drugs, he says, "but it's not clear yet that these smaller companies will have the development expertise or financial wherewithal to bring them to market."

In some cases, small companies form partnerships with larger, wealthier drug companies that underwrite the costs of large-scale studies and marketing, he says, "but those deals have to be done in areas where the larger companies perceive an economic benefit."

MRSA, for instance, offers a large market because it is affecting so many people and several antibiotics can be used against it. For lesser-known drug-resistant germs, the treatment options are fewer.

MRSA has been known in hospitals since the 1970s, but in recent years, new strains, which doctors call community-acquired MRSA, have infected people outside health care settings. One of these strains, known as USA300, was identified in 2000 and has been found in at least 21 states.

"What we're seeing is the emergence of a new epidemic strain of the MRSA in the community," says Daniel Jernigan, medical epidemiologist at the Centers for Disease Control and Prevention (CDC).

The CDC has reported on the new community strain since 2000, and it reported in March that the strain had caused outbreaks in hospital nurseries in Chicago and Los Angeles. Nine of the 22 infected babies required hospitalization. Other studies have reported longer hospital stays and higher death rates in MRSA-infected patients.

Staph aureus is the most common cause of the estimated 12 million skin infections each year in the USA, Jernigan says. A study in 2003 found that about one-third of people carry staph in their noses and just under 1% of people carry MRSA. Most carry the bacteria without becoming ill.

"We think the number of people carrying MRSA is increasing," Jernigan says, but the new studies are not yet completed.

It's not certain how common MRSA infections are. A CDC study based on hospital discharge data estimates that in 1999-2000, nearly 126,000 people were hospitalized each year for MRSA infections, a rate of nearly 4 per 1,000 hospital discharges.

Another study of 11 emergency rooms across the country found that almost 60% of skin abscesses tested were caused by MRSA, Jernigan says.

The new super-strain of MRSA has been concentrated in geographic regions, including California, Texas and Georgia, but Kaplan says that is changing. "It's in Pittsburgh, Memphis, St. Louis, Omaha. It's becoming more common on the East Coast now. It's literally all over the country."

University of California researchers who sequenced the genome of USA300 reported in the March 4 issue of The Lancet that the strain contains genes that make it hardy and able to cause "unusually invasive disease" such as severe blood infections and necrotizing pneumonia, in which lung tissue is destroyed.

Community-acquired MRSA has sidelined athletes, including players with the Washington Redskins, St. Louis Rams and San Francisco 49ers, as well as dozens of high school and college football players, wrestlers and basketball players. It has broken out in prisons, military bases and day care centers, anywhere there is crowding, poor hygiene and broken skin.

You don't have to be in a gym or a jail to be at risk. "You just have to be living," Kaplan says.

"This is not a superbug from a locker room; it's just out in the community," Kaplan says. "We've got 1,700 kids coming into our hospital with staph infections. They're not playing football. They're babies. Why this has been happening over the last 10 years vs. 20 years ago, we don't know."

Barriers breaking down

Strains of MRSA that have been known in hospitals for decades still account for most of the cases. Until a few years ago, says CDC epidemiologist John Jernigan (no relation to Daniel Jernigan), "MRSA was almost exclusively associated with hospitals." The types in the community are genetically different from those found in hospitals, he says, but that line is blurring.

"There used to be this very sharp distinction. However, we have the sense that more and more those strains associated with the community are finding their way into the hospital and causing health care-associated infections."

MRSA spreads through skin-to-skin contact and can be passed by using shared objects, such as razors or towels. It frequently hits more than one person in a family, and researchers in Canada have found that pets and their human owners can pass it back and forth.

"We're seeing transmission of MRSA from people to pets and pets to people," says researcher Scott Weese of the Ontario Veterinary College at the University of Guelph. "It raises the question: Can animals be a reservoir and play a role in this ping-ponging in households?"

He says dogs, cats, rabbits and ferrets have been found carrying the USA300 strain. As in people, it can cause serious skin infections and other illnesses.

"It shows pets are mimicking what's going on in the human situation," Weese says. "We're seeing more transmission in households than in the past."

Until their son was diagnosed, Bryce's parents had never heard of MRSA.

"Never heard of it, never even thought a little bacteria could do something like this," says Scott Smith, who owns a machine shop near their home in Santee, Calif., outside San Diego.

It's unclear how Bryce caught the bug, but his parents believe he may have picked it up while they were out Christmas shopping.

The family's ordeal started with a simple cold. Bryce was having sniffles a couple of days before Christmas, but on Christmas night, his parents saw he was breathing rapidly, and they worried that he might have asthma.

They called their pediatrician, who saw them two days later, dismissed the ailment as a simple viral infection and told the parents, "I've seen this a million times."

But as the days passed, the baby's condition worsened. The parents called the doctor two more times. "He said, 'You guys are new parents,' " and he told them not to worry so much.

Finally, in the early hours of New Year's Day, "we looked at him, and I said, 'I'm afraid if I go to sleep he won't be alive in the morning,' " Smith says. "We rushed him to the hospital."

At Children's Hospital of San Diego, "it was almost like a movie script," he says. A nurse tested Bryce's blood oxygen level, and "within 30 seconds they had 10 people on him."

'Just eating away' at him

Doctors said the infection had solidified in Bryce's right lung, and surgery was needed right away to clear the lung. "They had five chest tubes in him, because the infection was not only inside the lungs but outside the lungs and just eating away at his chest."

For 12 days, the Smiths didn't know whether Bryce would make it.

Then he was put on a breathing machine. He was put into a drug-induced coma and given intravenous vancomycin, a drug that is known as the last line of defense against MRSA.

The drug is "like fire going through the veins," Smith says. "With Bryce, at that point they had him asleep, and he was asleep for six weeks, so I feel lucky that he didn't have to feel the pain of vancomycin."

Today, Bryce is almost back to normal, but Smith says he and his wife won't let anyone touch him without washing their hands first.

"I felt so guilty," he says. "What keeps going through my mind is that as my son laid there at the house, we were literally watching him die and we didn't know."

Jan. 20, 2006 — Considered a "silent epidemic" by some public health experts, antibiotic-resistant staph infections are a growing threat to public health.

Almost 1 percent of the U.S. population — about 2 million people — carry drug-resistant staph without symptoms. The medical name for the infection is methicillin-resistant staphylococcus aureus, or MRSA. 

Here's what you need to know about MRSA:

What exactly is MRSA?

MRSA is a kind of bacteria that causes staph infections. Because it is resistant to many antibiotics, MRSA can be very difficult to treat, resulting in major infections and even death.

How does someone get MRSA?

There are two major classifications of MRSA, depending on the route of infection: The more common one is hospital-acquired MRSA, in which patients are infected during medical treatment, and the other is community-acquired MRSA, in which patients are infected during their normal daily routines.

MRSA can live just about anywhere, from medical equipment to grass in the park. The bacteria enter the body wherever they can find an opening, from minor cuts to inhalation through the mouth or nose. Testing positive for MRSA does not automatically mean that you are sick. Around 1 percent of the population is a MRSA carrier, meaning the carrier can spread the bacteria without necessarily becoming ill.

How common is MRSA?

MRSA is becoming a bigger problem both in hospitals and in the community. The Centers for Disease Control and Prevention recently reviewed the prevalence of MRSA in intensive care units and found a dramatic increase over time. In 1992, 36 percent of the S. aureus bacteria in ICUs were MRSA, but by 2003, that number rose to 64 percent. 

Using data from 1999 and 2000, the CDC estimates that more than 125,000 people a year are hospitalized for MRSA infection. People over age 65 or living in the southern part of the United States are most likely to be affected.

What happens when someone becomes infected with MRSA?

Hospital-associated MRSA is generally more serious because it often occurs in people who have weakened immune systems because of age (very young or very old) or illness. These patients frequently acquire MRSA infections at surgical sites, where it can spread to the bloodstream and cause damage to such organs as the lungs and heart.

In otherwise healthy people, MRSA generally shows up as a skin infection. It can cause painful swellings and growths that may require surgery.

In rare instances, MRSA has been associated with "flesh eating" bacterial disease, in which tissue begins to decay rapidly upon infection. These patients can require amputation of an arm or leg to prevent the bacteria from spreading to other parts of the body.

How is MRSA treated?

MRSA is generally treated with some combination of antibiotics and surgery, depending on where the infection is. Although MRSA is resistant to some forms of antibiotics, it's not usually able to escape them all. The newer antibiotic vancomycin is often a current choice in treating MRSA, but the bacteria are now showing some signs of becoming resistant to this drug too. 

Minor skin infections with MRSA may just be drained and cleaned.

How did MRSA become resistant to antibiotic treatment?

Bacteria generally start showing resistance fairly quickly to any medication that's designed to defeat them. Most often, a mutation in the bacteria allows it to survive the drug treatment, and these surviving bacteria create many more copies of themselves that are also resistant. 

Scientists are trying to stay one step ahead of the bacteria by creating new drugs to defeat them. The public can help slow down bacterial resistance by not using any unnecessary antibiotic medications. For example, studies have shown that most cases of ear infection and bronchitis do not need to be treated with antibiotics. By refraining from antibiotic use in unnecessary situations, people help preserve the drugs' effectiveness for when they are truly needed!

By JOANNA SCHAFFHAUSEN

<<--Back
Pandemic Bug Returns as Community MRSA Strain

11:21 01 April 2005 
NewScientist.com news service 
Clara Penn 

A virulent type of community-acquired MRSA “superbug” that attacks healthy, young people has been found to be the descendent of a penicillin-resistant strain that caused serious infections worldwide 50 years ago.

Scientists fear that this offspring superbug strain - which causes serious boils and abscesses and can lead to a severe pneumonia - could pose a major public health threat in the future.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is genetically distinct from the strains prevalent in hospitals, and can cause infections in young people with no connection to healthcare environments.

Sickness ranges from relatively minor skin and soft tissue infections to a necrotizing pneumonia which destroys the lungs so rapidly that it can kill just 24 hours after infection. This is because most CA-MRSA strains carry a particularly vicious cytotoxin called Panton-Valentine leukocidin (PVL) toxin which destroys leukocytes.

Cases are still relatively rare but have been reported throughout the world, though this form of MRSA is a particular problem in the United States, where in some areas it accounts for 70% of all reported MRSA infections. While these bacteria are not multi-drug resistant - and can still succumb to the antibiotic vancomycin - treatment can be complicated.

Serious outbreaks
An international team of scientists has found that a strain of CA-MRSA known as the southwest Pacific clone is closely related to an older form of Staphylococcus aureus that caused a pandemic in the 1950s.

This older strain, known as phage type 80/81, was first discovered in neonatal infections in Australia in 1953 and went on to cause serious outbreaks of skin lesions, sepsis and pneumonia worldwide, often in young people and children. It was eliminated through the introduction of synthetic penicillins, such as methicillin, in the 1960s.

The team sequenced key genes from preserved specimens of 80/81, and compared these to genes from more than 1000 samples of Staphylococcus aureus. The older strain was almost identical to the southwest Pacific clone, and also closely related to another strain called the MRSA16 clone - commonly found in UK hospitals. Notably, the older strain also carried the genes for the PVL toxin.

The southwest Pacific clone has spread into Europe, where it has caused fatal pneumonia in France, Sweden and Latvia. Only two specimens have so far been found in the UK.

Mark Enright at the University of Bath, who led the study, says the results are alarming. “I have no doubt that this is going to cause serious public health problems in the UK and elsewhere in coming years. This is a very aggressive pathogen and it’s spreading rapidly.”

Journal reference: The Lancet (vol 365, p 1256)