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CDC Links Salmonella Outbreak to Lab Work

The Centers for Disease Control and Prevention reported Thursday that it is investigating a multistate outbreak of Salmonella Typhimurium infections. A preliminary analysis indicates the outbreak may be the result of exposure in clinical and teaching microbiology laboratories.

As of April 20, the CDC said 73 individuals infected with the outbreak strain of Salmonella Typhimurium have been reported from 35 states.  There has been one death and at least 10 people have been hospitalized. Several of those sickened are children who live with someone who works or studies in a microbiology lab.

The CDC said that during an epidemiologic study in February and March, 32 people were quizzed about possible exposures in the week before they became ill. Investigators compared their answers to a control group of 64 individuals of similar age previously reported to state health departments with other illnesses.

The investigators found that the ill persons (60%) were significantly more likely than the control persons (2%) to report a connection to a microbiology laboratory.

Many of those infected were either students in microbiology teaching laboratories or employees in clinical microbiology laboratories.  Several said they worked specifically with Salmonella bacteria in microbiology laboratories.

The New Mexico Department of Health found that the outbreak strain was indistinguishable from a commercially available Salmonella Typhimurium strain used in several of the laboratories, according to the CDC.

“These data suggest this strain is the source of some of these illnesses,” the CDC said, adding that “several children who live in households with a person who works or studies in a microbiology laboratory have become ill with the outbreak strain.”

Illness onset dates have generally ranged form Aug. 20, 2010 to March 8, 2011.  The number of new cases has declined substantially during the past several weeks, the agency said.

The CDC advised people who work with Salmonella bacteria in microbiology laboratories to watch for symptoms of Salmonella infection, such as diarrhea, fever and abdominal cramps. They should contact a health care provider if they or family members have any of these symptoms.

The agency also recommended that non-pathogenic (attenuated) bacteria strains should be used when possible, especially in teaching laboratories, to help reduce the risk of students or their family members becoming ill.

All students and employees using laboratories should be trained in biosafety practices, the agency emphasized, such as proper handwashing, not allowing lab coats to leave the lab, and not allow food, drinks or personal items like car keys or cell phones to be used while working in the laboratory or placed on laboratory work surfaces.

© Food Safety News
  • http://www.healthyfoodcoalition.org hhamil

    It appears that this is not AN outbreak; rather, it is a group of cases that have been aggregated based upon having the same outbreak strain.
    The CDC’s explanation clearly does NOT account for a significant minority of the cases in its epidemiological sample of 32 of the 73 cases.
    Just as it did in the 2008 tomato/pepper fiasco, the CDC appears to have put forward a partial explanation instead of doing what needs to be done and parsing the cases into, at least, 2 outbreaks. Unfortunately, the scientific community and the press, including Food Safety News, are allowing it to get away with this sleight of hand. Instead, according to the procedure used by the Center for Science in the Public Interest, this would be counted as a successfully completed investigation!
    I urge FSN to ask the clearly appropriate questions instead of participating in the mainstream practice of press release journalism.

  • Minkpuppy

    The CDC does account for the remaining cases. The article clearly states that several of the illnesses were children of people who worked or studied in a microbiological lab. There would be no need to question the children because they obviously contracted the illness from the parent that contracted it from the lab.

  • http://www.healthyfoodcoalition.org Harry Hamil

    It appears that this is not AN outbreak; rather, it is a group of cases that have been aggregated based upon having the same outbreak strain.
    The CDC’s explanation clearly does NOT account for a significant minority of the cases in its epidemiological sample of 32 of the 73 cases.
    Just as it did in the 2008 tomato/pepper fiasco, the CDC appears to have put forward a partial explanation instead of doing what needs to be done and parsing the cases into, at least, 2 outbreaks. Unfortunately, the scientific community and the press, including Food Safety News, are allowing it to get away with this sleight of hand. Instead, according to the procedure used by the Center for Science in the Public Interest, this would be counted as a successfully completed investigation!
    I urge FSN to ask the clearly appropriate questions instead of participating in the mainstream practice of press release journalism.

  • http://www.healthyfoodcoalition.org hhamil

    Minkpuppy,
    Since when is it appropriate to use “several” to describe 13 cases?
    That is how many ill persons (40%) in the epidemiological sample of 32 did NOT report any connection to a lab. And that doesn’t account for the 41 people who weren’t in the CDC’s epidemiological study.
    From what the CDC published, it is unclear which strain of Salmonella Typhimurium this is and how common it is. Furthermore, as I understand it and I am no expert, decisively narrowing down salmonella is sometimes not possible because of the limitations of the tests available. Thus, the fact that “the New Mexico Department of Health found that the outbreak strain was indistinguishable from a commercially available Salmonella Typhimurium strain used in several of the laboratories” may NOT be of limited use.
    So, I repeat, it appears that a significant number of these cases are NOT accounted for by the CDC’s current explanation. I urge FSN to ask more and better questions.

  • http://www.youtube.com/watch?v=Xk9IvhV3aAs Doc Mudd

    “Clowns to the left of me, jokers to the right. Here I am, stuck in the middle…” [Gerry Rafferty]
    The CDC actually has to remind researchers, microbiology teachers and students to be careful how they handle salmonella in the lab! These gifted laboratory geniuses are to be our medical experts in the 21st century.
    An ex-insurance salesman postures as some sort of semi-coherent amateur public health epidemiologist, pompously backseat driving for the CDC! This is what passes as medical expertise in the hearts and minds of the loopy ‘health-conscious’ pop culture.
    Good Lord, science has entirely failed our generation and is busily failing the next. If the reported salmonella illnesses aren’t newsworthy, certainly the raging epidemics of brazen incompetence and scientific illiteracy are.

  • http://www.healthyfoodcoalition.org Harry Hamil

    Minkpuppy,
    Since when is it appropriate to use “several” to describe 13 cases?
    That is how many ill persons (40%) in the epidemiological sample of 32 did NOT report any connection to a lab. And that doesn’t account for the 41 people who weren’t in the CDC’s epidemiological study.
    From what the CDC published, it is unclear which strain of Salmonella Typhimurium this is and how common it is. Furthermore, as I understand it and I am no expert, decisively narrowing down salmonella is sometimes not possible because of the limitations of the tests available. Thus, the fact that “the New Mexico Department of Health found that the outbreak strain was indistinguishable from a commercially available Salmonella Typhimurium strain used in several of the laboratories” may NOT be of limited use.
    So, I repeat, it appears that a significant number of these cases are NOT accounted for by the CDC’s current explanation. I urge FSN to ask more and better questions.