Doctors think of drug-resistant Staph germs as living in two different worlds. One type lives in hospitals and can defy a wide array of antibiotics. The other lives in the community and typically resists only one or two drugs.
That's so 90s.
This bug is showing up in hospitals more and more.
This bug is showing up in hospitals more and more. iStockphoto.com
A new study in the journal Emerging Infectious Diseases finds a big jump in both types of drug-resistant staph inside U.S. hospitals, and gives some suggestions as to why there's an increase.
Between 1999 and 2006, there was a 90 percent increase in the incidence of methicillin-resistant Staphylococcus aureus, or MRSA, among patients admitted to U.S. hospitals. (Methicillin and its chemical cousins are artificial penicillins that used to be reliably effective against Staph.)
Zeroing in on this phenomenon, researchers discovered it's largely due to a seven-fold jump in cases of community-associated MRSA between 1999 and 2006. In other words, it's mostly due to community-associated Staph making its way into hospitals.
There are many ways MRSA is getting from the community into hospitals.
"Not only are people coming into the hospital with community-associated Staph, but also doctors who are treating patients in outpatient facilities are bringing it in as well," says Eili Klein of Princeton University, a study author.
There's also a third avenue — community residents who come into the hospital to visit patients or conduct other business.
Why does it matter that community-associated MSRA is so much more common in hospitals? First, Staph infections can be dangerous. An estimated 20,000 Americans die of MRSA infections each year. And even though community-associated Staph is more treatable than the hospital-associated kind, it can cause serious illness and death.
Second, it matters a lot to the kind of treatment patients get and what it costs. It also matters to the larger battle against antibiotic resistance — a battle that's currently being lost.
Confronted with a feverish hospital patient who has a likely bacterial infection, doctors can't wait the 24 to 48 hours it would take to get results of a standard bacterial culture to determine which kind of bug it is. So they tend to assume it's a hospital-associated MRSA infection, which is resistant to a number of front-line antibiotics that work against community-associated MRSA.
In other words, they prescribe expensive "big gun" antibiotics. The more these drugs are used when they're not necessary, the more likely it is that resistant staph microbes will emerge.
The new study — part of a project to fight antibiotic resistance called Extending the Cure — shows that a growing number of MRSA infections among hospital patients are really community-associated and can be treated perfectly well with less-fancy antibiotics.
There is a quick test that can distinguish the type of MRSA, Klein says, "but it's expensive and not available on a widespread basis."
What's needed, he says, is for doctors to know what kinds of MRSA are circulating in their communities — inside and outside hospitals — so they can treat accordingly. Pennsylvania mandates such surveillance, but other states don't, and state public health departments don't have the resources these days to take it on.
"Most insurance companies won't pay for microbial swabs done for surveillance purposes," Klein says. "And most hospitals aren't set up to share information on resistant organisms. So we need some sort of regional coordination. And we need to show these mechanisms will work in the long run to reduce costs and save lives."