Staph strain found in child care worker raises questions

Kathleen Blanchard's picture
Source of Staph infection in child care worker a mystery

A recent finding has left some unanswered questions about the source of a new type of Staphylococcus bacteria, commonly known as staph found in a child day care worker in Iowa.

The "surprise" finding, say the researchers, is not a cause for concern, but the discovery was unexpected because the type of staph is normally associated with livestock exposure.

According to researcher, Erin Moritz, a doctoral student in epidemiology in the UI College of Public Health, the child day care worker had no contact with livestock.

Where did ST398 strain come from?

The strain, ST398 can be spread from livestock to "community members and then from person to person", writes the study author." It can potentially be transmitted in food; several studies have documented ST398 in raw meats." Moritz noted some raw meat in Iowa has been found to carry the Staph strain.

The original report was published April 4, 2011 in the journal "Emerging Infectious Diseases".

According to Moritz, "We weren't expecting it. Most people who have been found to carry ST398 have had contact with animals, especially agricultural animals, and she (the child care worker) reported no contact. That's what was unique about it."


The Staph strain, ST398 was originally isolated in the Netherlands, five years ago, and is related to bacteria found in swine workers in 2009. The child day care Staph strain is treatable with methicillin, unlike that found in swine flu workers, which is methicillin resistant.

The only other instance of ST398 found in the US was in a group from the Dominican Republic, living in New York City.

Tara Smith, Ph.D., assistant professor of epidemiology in the College of Public Health and advisor to Moritz said, "We know that about a third of us carry some strain of Staphylococcus aureus. This is just a novel strain that has been picked up in the last five years, and we really don't know a whole lot about it. It's not any worse than your run-of-the-mill human staph that's out there in the community already," Smith added.

Interestingly, ST398 has been found in raw meat. A recent study from theTranslational Genomics Research Institute, published in the journal "Clinical Infectious Diseases", revealed high levels of Staph aureus in meats and poultry that was downplayed by the Meat Institute.

The finding highlights the importance of boosting surveillance of infectious diseases in the US, which raises questions that researchers say should be looked at more closely. No one knows how the child day care worker picked up the new strain of Staph that normally comes from exposure to livestock, but interestingly has been found in raw meat.

CDC: Emerging Infectious Diseases
"Livestock-associated Staphylococcus aureus in Childcare Worker"
Erin D. Moritz and Tara C. Smith

University of Iowa News Release

Clin Infect Dis. (2011)
doi: 10.1093/cid/cir181