Preventing The Spread Of Infection
Dr. Lipsky: I’m interested in your thoughts on what we do when we know that a patient is colonized with MRSA, either in a wound or in the anterior nares. Dr. Lavery, if that patient is making a visit to your clinic, how do you handle this person who is chronically colonized with MRSA? Do you have some kind of isolation procedures? Do you take special precautions?
Dr. Lavery: I think this is really a new thought process. In my institution, it’s a relatively new disease process or disease focus. Down the road, it seems that empirically, enhanced precautions such as isolation may be a logical approach, especially with such a high incidence of infection in this group. However, I think it’s something that probably needs to be discussed institution by institution with infectious disease colleagues before deciding on an appropriate systematic approach.
Dr. Armstrong: I just don’t think widespread isolation procedures are happening right now in the United States. I certainly don’t think there are that many patients who are being swabbed for potential colonization for epidemiologically significant organisms. When we have a patient who has a previous history of diabetic foot infection with MRSA, it might raise some interesting questions, but I’m not certain that this is going on in any widespread sense in the U.S. at present.
Dr. Lipsky: Dr. Armstrong, you have traveled all over the world and visited diabetic foot clinics in most of the cities that you travel to. Don’t you see in Europe, for example, that they are isolating or at least separating these patients?
Dr. Armstrong: Yes, indeed. In fact, at the clinic that I attend very frequently in Manchester, England, there have been what I would consider to be heroic measures taken to identify and isolate outpatients being treated for wounds with histories of MRSA.
Dr. Lipsky: I can tell you that from my time in the U.K. in Oxford no patient can be admitted to the bone infection unit without first having had screening cultures for MRSA. The patients are kept in a holding area, either off-site or in a nursing home, until the cultures come back negative. Then the patients can be admitted into the hospital.
Those who need to come in despite positive cultures are put in special isolation rooms where signs are posted and visitors have to put on gowns and gloves. Using these methods in Oxford, they have kept the rate of MRSA in their site quite low, despite the fact that they work in a tertiary referral center that tends to get the patients who failed antimicrobial therapy and are therefore more at risk for MRSA. Some other hospitals in the U.K. have very high rates of MRSA.
Dr. Joseph: Even with this isolation, Boulton, et. al., found that between 1999 and 2003, the percentage of Staphylococcus in their diabetic foot infections which were methicillin resistant actually increased.48,49
Dr. Armstrong: I believe the proportion of patients with MRSA doubled from 15 to 30 percent. The question is if those isolation measures were not taken, would the rate be 50 percent or greater as it is in so many large institutions?
Dr. Joseph: It is a main hospital. Hospitals that did practice intensive isolation and contact precautions were in fact able to really minimize their MRSA patient loads. With some hospitals having 40, 50 or 60 percent of their Staph infections being methicillin resistant now, there’s not enough isolation rooms in these hospitals. It’s great medicine, but is it practical, especially now that we have not only the hospital-acquired MRSA but the community-acquired MRSA?
Dr. Armstrong: I think these are very important things that I think every one of us either reading this or participating in this discussion have to really think about for the future. Isn’t it true, Dr. Lipsky, that there are data to show that if the prevalence of MRSA gets over a certain threshold, say 20 percent, in your community, that it’s just very difficult to completely eradicate the problem?
Dr. Lipsky: Yes, there is evidence supporting that statement. In certain places like the Netherlands, where they’ve made extraordinary isolation efforts to avoid having MRSA become entrenched in their hospitals, they have been successful at doing that. However, once MRSA is established in a population and grows beyond a certain threshold — and 20 to 30 percent seems to be about where that threshold is — there are very few hospitals that manage to eradicate it in the long term.
So if you are blessed by being in one of the places where MRSA is not a big problem right now, do what you can to avoid it.
If you are in a facility in which you see a lot of MRSA, I think we have to really carefully think through what we’re doing when we’re screening patients. The culture that was positive last week might actually be negative this week. The one that was negative last week might actually be positive this week. Even if you do screen, you’re not absolutely certain that the patients who you are seeing have the organism because we know that there is a fair amount of turnover of those organisms in the anterior nares.
I don’t think we really know the answer about screening and isolation, but I think it’s a critical area to address because most clinics don’t have enough rooms right now, and can’t offer specially designated isolation rooms. The same is true on the inpatient service with isolation beds.
A recent paper in JAMA looked at the adverse effect of isolation.50 They found that if you put patients in isolation, they are less satisfied with their care and they are seen by their providers less often. I think we have to be very careful about tossing patients into isolation.
One other concern is that some long-term care institutions will not accept patients who are infected or colonized with MRSA. Thus, patients are often treated with antibiotics solely to try to eliminate colonization or providers decide against culturing the nares or wound for fear of uncovering MRSA. Neither of these are optimal for patient care.
Washing Your Hands: Emphasizing The Role Of Personal Hygiene
Dr. Lipsky: I usually culture the anterior nares of patients who have had recurrent staphylococcal infections. We find that they more often than not are colonized with S. aureus. If we then successfully eradicate colonization, the recurrent infections often will stop.
I can recall one interesting exception to this scenario. An elderly man kept getting infected with S. aureus despite the fact that he did not have nasal Staph colonization. It turned out his wife, who was colonized with S. aureus, was changing his dressings.
Studies have shown that during the day almost everyone touches his or her nares, including most physicians. People who have S. aureus in their nose get it on their hands and it goes from their hands to other people’s hands and then to their noses.
Ultimately it can colonize a break in the skin and cause an infection. Some people colonized with S. aureus are heavy shedders of the organism while others are not. Heavy shedders in health care institutions have been linked with the spread of Staph infections.
There is a tremendous body of literature from the 1950s when penicillin-resistant S. aureus was the problem. There was a terrible problem with nosocomial S. aureus infections for which no other antibiotics were available. Unfortunately, this experience has been largely forgotten.
Dr. Lavery: I spend a lot of time harping on residents and technicians to wash their hands.
Dr. Lipsky: Several studies have shown that it’s very difficult to get health care workers to wash their hands if it’s not their normal habit. Simply telling patients to ask anyone who examines them to wash their hands first is quite effective and obviously inexpensive. No providers are going to turn down such a request.
Dr. Lavery: When I go see patients, I make sure they see me wash my hands.
Dr. Lipsky: Well, it also makes the point to patients that if it’s important enough for the doctor to wash, it’s important for the patient and their family members who are dressing their wounds to do that before taking care of their wounds.