Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Skin Problems & Treatments Health Center

Font Size

Deadlier Strain of MRSA Emerges

'USA600' Strain Is Partly Resistant to Treatment by Another Antibiotic
WebMD Health News
Reviewed by Louise Chang, MD

Nov. 2, 2009 (Philadelphia) -- A newly discovered strain of drug-resistant staph bacteria is five times more deadly than other strains, a new study suggests.

Adding insult to injury, the new superbug appears to have some resistance to the antibiotic commonly used to treat it, researchers report.

Half of patients infected with the new strain of MRSA (methicillin-resistant Staphylococcus aureus) died within 30 days, says Carol Moore, PharmD, a research investigator in infectious diseases at Henry Ford Hospital in Detroit.

That compares to only about 10% of patients infected with other MRSA strains, she tells WebMD.

Moore and colleagues studied 16 people infected with the new strain, called USA600, and 64 people infected with other MRSA strains at their institution.

MRSA strains are typically susceptible to the antibiotic vancomycin, Moore says. But the USA600 strain was at least party immune to vancomycin, she says.

Though the new superbug appears to have unique characteristics that make it deadly, other factors, such as the patients' older age, may have played a role, Moore says. The average age of patients infected with the USA600 strain in the study was 64 vs. 51 for patients with other MRSA strains.

The study was presented at the meeting of the Infectious Diseases Society of America.

While USA600 infections have only been seen in hospitalized patients to date, a growing number of MRSA infections are being seen in otherwise healthy people in the community.

"In light of the potential for the spread of this virulent and resistant strain and its associated mortality, it is essential that more effort be directed to better understanding this strain to develop measures for managing it," Moore says.

MRSA Spikes in Summer Months

Other new research presented at the meeting shows a spike in MRSA infections in summer months -- probably driven, experts says, by the rise in cases outside the hospital setting in recent years.

Loyola University researchers studied the medical records of more than 400,000 people admitted to a Chicago hospital from 2000 to 2008. They identified about 1,300 people who tested positive for MRSA.

The number of infections did not vary by season during the first four years studied.

But from 2004 to 2008, the risk of being infected was about 30% greater in the summer months than in the winter or spring.

That's likely due to the rise in community-acquired infections, says the CDC's Fernanda Lessa, MD, who tracks MRSA but was not involved with this study.

"We know that the skin is a major entry point for the bacteria, so one would expect more infections in the community in the summer when your wear fewer clothes and are more prone to skin lesions," she tells WebMD.

Today on WebMD

Pictures and symptoms of the red, scaly rash.
woman with dyed dark hair
What it says about your health.
woman with cleaning products
Top causes of the itch that rashes.
atopic dermatitus
Identify and treat common skin problems.
itchy skin
shingles rash on skin
woman with skin tag
Woman washing face
woman washing her hair in sink
close up of womans bare neck
woman with face cream