Drug-Resistant Staph a Growing Concern
3 New Studies Show How Tough It Can Be to Treat MRSA Infections
Sept. 28, 2006 -- Drug-resistant staph infections -- called MRSA -- are common, tough to treat, and may become an even bigger problem unless this "super bug" can be squashed.
That's the finding in three new studies on MRSA (methicillin-resistant Staphylococcus aureus) bacteria.
The studies were presented today in San Francisco, at the American Society for Microbiology's 46th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
MRSA causes infections in different parts of the body. It's tougher to treat than most strains of Staphylococcus aureus because it's immune to some commonly used antibiotics. That's why it's sometimes called a "super bug."
MRSA usually causes mild skin infections, such as pimples or boils. But it can also result in more serious skin infections or infect surgical wounds, the bloodstream, and organs.
While most MRSA infections aren't serious, some can be life-threatening.
Many public health experts are alarmed by the spread of tough strains of the bacteria.
MRSA can be deadly, costly, and may be poised to do even more damage, according to the first study presented in San Francisco.
Dror Marchaim, MD, of Israel's Tel-Aviv Medical Center analyzed 21 studies involving 1,131 MRSA patients and 1,587 patients with drug-sensitive Staphylococcus aureus.
MRSA patients fared worse, across the board, he found.
They were 36% more likely to die, stayed in the hospital seven days longer, and their hospital bill was $7,250 to $11,500 higher, Marchaim says.
Marchaim predicts that if MRSA replaces drug-sensitive Staphylococcus aureus, "this will add annually 2,700 cases of death, 210,000 days of hospitalization, and $310 million to hospital expenditures.
"Strategies to better control and treat MRSA are required," Marchaim writes.
Treatment Often Fails
First-line treatment for MRSA often fails to kill the bacteria.
In fact, first-line MRSA treatment failed in a quarter of the patients studied by Julia Dombrowski, MD.
Dombrowski works at the University of California, San Francisco. She studied 215 cases of serious MRSA infection.
Many of the patients in her study also faced other major challenges, including diabetesdiabetes (19%), HIV (14%), homelessness (34%), injection drug use (46%), and alcohol abuse (26%).
"Overall, 53 patients (25%) were not cured with the first round of antibiotic therapy, even when it was given for the recommended length of time," Dombrowski writes.
Treatment was most likely to fail in patients with MRSA bone infections.
"The high rate of treatment failure seen in this study suggests that we should look at other therapies, especially for MRSA bone infections, to see if they are more effective," Dombrowski writes.
She suggests several strategies -- including longer treatment, combination drug therapy, and using different antibiotics -- and calls for studies to test those approaches.
MRSA May Return
MRSA returns in almost 10% of MRSA patients, according to the CDC's Zachary Rubin, MD, and colleagues in the third study.
They sifted through CDC data on 7,629 MRSA patients from 2004-2006. All had evidence of MRSA blood infection.
And nearly 10% of them had MRSA show up in their blood again 30 days after the bacteria was first spotted.
MRSA recurrence was more common among people who recently or frequently got health care and among those who had diabetes or HIV/AIDSHIV/AIDS, were black, or abused injected drugs.