MRSA Madness and Tomato Update

Methicillin-resistant Staphylococcus aureus (MRSA) is here to stay. Although it is most problematic in healthcare settings, particularly hospitals, it is present in the "community" as well, and therefore will become a consideration for outdoor and wilderness enthusiasts.

In mid-April (2008), the following press release appeared:

One in Every 20 Healthcare Workers Is (a) MRSA Carrier
By Michael Smith, North American Correspondent, MedPage Today

GENEVA, April 15 -- One in every 20 healthcare workers carries methicillin-resistant Staphylococcus aureus, researchers here said.

This study suggests that healthcare workers sometimes play a role in the transmission of MRSA. But the vast majority is without symptoms and only 5.1% have full-blown clinical infections, according to Stephan Harbarth, M.D., of the University Hospitals of Geneva, and Werner Albrich, M.D., of University Hospital Bern.

One implication is that screening efforts aimed at symptomatic infections are likely to miss a large proportion of colonized healthcare workers who might transmit the bacteria, they wrote in a literature review in the May issue of Lancet Infectious Diseases.

Instead, they said, "aggressive screening and eradication policies" should be used in an outbreak and in situations where MRSA has not reached highly endemic levels.

The researchers looked at 127 studies published from January 1980 through March 2006, and on the basis of the published evidence, they concluded that healthcare workers are usually vectors, rather than the main sources of MRSA transmission, implying that "good hand hygiene practices remain essential to control the spread of MRSA."

4.6% of approximately 33,000 health care workers were carrying MRSA, the researchers found - usually in the nose, although other sites were found. Most (94.9%) of the carriers had no symptoms. Risk factors included chronic skin diseases, poor hygiene practices, and having worked in countries with endemic MRSA.

"Our search revealed 18 studies with proven and 26 studies with likely transmission to patients from healthcare workers who were not clinically infected with MRSA, the researchers said. That finding suggested that a recent recommendation that screening efforts focus on healthcare workers with symptomatic infection is likely to miss the boat.

"Staphylococcal dispersal is mainly dependent on whether the person is a nasal carrier," they said, so that "screening of infected healthcare workers only will likely miss a large number of asymptomatic personnel capable of transmitting MRSA to patients. They added that MRSA screening - and treatment to eradicate colonies of the bacteria - "should always be part of a comprehensive infection control policy including staff education and emphasizing high compliance with hand hygiene and contact precautions."

It's also important to avoid "feelings of guilt or stigmatization" among those found to be colonized, they said. "In analogy to needle-stick injuries, MRSA carriage or infection in a healthcare worker should be considered an occupational hazard," they said.

MRSA has been around since the 1960s and 1970s, when S. aureus developed resistance to the types of "semi-synthetic" penicillin (such as methicillin) used to treat the infection. Because the antibiotic vancomycin has been fairly effective against MRSA, and because there are other antibiotics, such as daptomycin, liezolid, tigecycline, and developmental drugs, which are effective against MRSA, we do not have a germ run completely wild, but we definitely have an in-hospital surge in infections and increasing indications that MRSA is gradually increasing its prevalence outside of the hospital.

It has been estimated that the general population may carry MRSA on the skin or in the nose at a rate of anywhere from 1% to 30% of the group studied. However, it is important to point out that the real frequency in the community is unknown, so there is not yet a cause for panic, but rather, for rational recommendations, mostly around hand-washing, disinfection of common surfaces, and general hygiene.

For outdoor enthusiasts, the following risk factors apply:

1. High prevalence of MRSA in the local community
2. Recurrent skin disease
3. Crowded living conditions (e.g., military barracks)
4. Participation in contact sports (e.g., wrestling)
5. Member of Native American, Pacific Island, or Alaskan Native populations
6. Shaving of body hair
7. Sharing equipment that is in prolonged contact with skin (e.g., paddling jacket)

Ten years ago, when an abscess was drained in the emergency department, it was considered unnecessary to send a sample of the pus or discharge from a wound for a culture to determine which bacteria might be present. Today, it is much more reasonable to do this to determine the presence or absence of MRSA.

Personal hygiene is very important, particularly if you come in contact with infected skin. It is essential to do full hand-washing with soap and water, and also to consider utilizing disinfectant gel. If you use a disinfectant soap, be sure to allow sufficient contact time with the skin - up to 3 minutes is fine before rinsing, rather than a quick scrub and rinse. Clothes that are put through a hot cycle are generally safe - on the trail, try to use very hot water to wash clothing, of course taking care to avoid any skin burns.

Tomatoes and Salmonella Update

The FDA has announced that it has lifted its Salmonella warning on tomatoes. The agency advises that people at highest risk for the illness, including the immunocompromised and elders, should avoid raw jalapeno and serrano peppers. The message here is that no definitive food source culprit has been identified for this particular outbreak of Salmonella infections. I recommend that all people use prudent handling techniques whenever preparing and serving food.

image courtesy of www.cdc.gov

Preview the 25th Anniversary & Annual Meeting of the Wilderness Medical Society, which will be held in Snowmass, Colorado July 25-30, 2008.

Tags: MRSA, methicillin-resistant Staphylococcus aureus, wilderness medicine, outdoor medicine, healthline

Labels: methicillin-resistant Staphylococcus aureus, MRSA

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