Infection Control: The Bug that Bounced Back

Armed with methicillin, the healthcare industry defeated Staphylococcus aureus infections over 40 years ago. But now the majority of these bacteria are resistant, forcing hospitals to develop a new plan of attack.
By: 
Ryan Hiett

 

May 22, 2006
Lena M. Napolitano, M.D., is professor of Surgery, Chief, division of Acute Care Surgery, director of Surgical Critical Care and program director of the Surgical Critical Care Fellowship and serves as associate chair for Critical Care within the Department of Surgery.

It’s like a never-ending battle — that’s how Lena Napolitano, M.D., describes the recent and sharp rise in nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections.

The professor in the department of surgery at the University of Michigan said MRSA is now the most frequent cause of hospital-acquired pneumonia and surgical wound infections, as well as the most common gram-positive bacteria in hospitals today.

But that hasn’t always been the case — in fact, the first signs of MRSA weren’t until 1961, two years after methicillin was invented to combat Staphylococcus aureus.

After a slow and steady increase, MRSA multiplied by leaps and bounds in the past decade.

“It used to be that methicillin-sensitive [staphylococcus] aureus was the most common bacteria that caused infection in the hospital setting from gram-positive organisms,” she said. “Now it’s MRSA.”

She doubts that the high number will be going down anytime soon, either.

“Ten years from now, probably 100 percent of infections will be MRSA, and we’ll be seeing a rise in some other bug,” she said.

Preventing the Infection

There are a number of reasons why the bacteria has crept into the healthcare community — Dr. Napolitano says one is because antibiotics are being prescribed more often, causing Staphylococcus aureus to build resistance.

“But that’s not the only reason,” she said. “We have more ill patients that are spending a longer time in the hospital setting. We also have patients receiving other antibiotics, which can suppress all the other organisms except for MRSA.”

Hospitals are struggling with the bacteria’s spread as infection control authorities such as the Society for Healthcare Epidemiology of America (SHEA) and the Centers for Disease Control and Prevention (CDC) develop new guidelines to prevent transmission.

“There’s a big push to say that appropriate infection control is very important,” Dr. Napolitano said. “We need to find out who has [MRSA], and we need to make sure that appropriate infection control practices occur.”

She said it is important to swab every patient who comes into the ICU for MRSA colonization in the nose area.

“In the ICU, every patient is being looked at,” she said. “In the hospital setting, the guidelines are varied. The CDC says patients should only be cultured who are at high risk, while SHEA says everyone who walks in the door should be cultured.”

A major change was made last year to the Surgical Infection Prevention (SIP) guidelines to accomodate the trend.

“All the time the SIP guidelines have said that to prevent surgical site infection, you need to be careful to use antibiotics within one hour before surgery,” Dr. Napolitano said.

Now, however, if the patient is either colonized or infected with MRSA, the guidelines say that an anti-MRSA drug must be given.

“That’s what’s different,” Dr. Napolitano said. “And it’s radically different than what we’ve done in the past. Now that MRSA is the most common infection in terms of surgical site infection, the guidelines have changed.”

And although hospitals are pushing for all employees to follow the guidelines, 100 percent compliance may be difficult – a 2005 study by the American Medical Association found that only 55.7 percent of patients were receiving a dose of antibiotics within the appropriate time frame.

“It was identified that many people were not following the guidelines, in terms of antimicrobial prophylaxis,” she said.

Dr. Napolitano says the focus of any hospital-acquired infection should be prevention rather than treatment.

“A number of studies have documented that if you get infected with this resistant bacteria, you do worse, you have a longer length of stay and higher hospital costs,” she said. “So we’re trying to do everything we can to prevent the infection rather than treat it.”

Sidebar

The main mode of transmission of MRSA is via hands (especially healthcare workers' hands), which may become contaminated by contact with:
• Colonized or infected patients
• Colonized or infected body sites of the personnel themselves
• Devices, items or environmental surfaces contaminated with body fluids containing MRSA
Standard precautions, which include proper handwashing, gloving, masking, gowning, appropriate device handling and handling of laundry should control the spread of MRSA in most instances.
Source: The Center of Disease Control and Prevention (CDC)