Today the CDC made a curious announcement—a multistate outbreak of Salmonella Enteritidis infections, primarily in Texas and Oklahoma, all linked to a mysterious Mexican-style fast food restaurant chain known as “Restaurant Chain A.”
The investigation was unable to identify a specific food item as the culprit, but data indicated that contamination likely occurred before the product reached Restaurant Chain A locations. The epidemic curve seen in the outbreak is consistent with those observed in past produce-related outbreaks—with a sharp increase and decline of ill persons that spanned one to two months. Ground beef was found to be an unlikely source due to the handling and cooking processes used by Restaurant Chain A.
This outbreak now appears to be over.
Public health investigators used DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They used data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections. The PFGE pattern in the outbreak has been seen before in PulseNet, and in the past typically caused 2-3 cases per month.
As of January 19, 2012, a total of 68 individuals infected with the outbreak strain of Salmonella Enteritidis have been reported from 10 states. The number of ill persons identified in each state with the outbreak strain was as follows:
- Texas (43)
- Oklahoma (16)
- Kansas (2)
- Iowa (1)
- Michigan (1)
- Missouri (1)
- Nebraska (1)
- New Mexico (1)
- Ohio (1)
- Tennessee (1)
Among persons for whom information was available, illnesses began on or after October 13, 2011. Ill persons range in age from <1 to 79 years, and the median age was 25 years old. Fifty-four percent of patients were female. Thirty-one percent of patients were hospitalized. No deaths were reported.