29.04.2011

Multistate Outbreak of Human Salmonella Typhimurium Infections

CDC is collaborating with public health officials in many states to investigate a multistate outbreak of Salmonella Typhimurium infections associated with exposure to clinical and teaching microbiology laboratories. Investigators are using DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.
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.