CDC is collaborating with public health officials in many states, the US Food and Drug Administration (FDA), and the US Department of Agriculture’s Food Safety and Inspection Service to investigate a nationwide increase of Salmonella Enteritidis (SE) infections with an indistinguishable pulsed-field gel electrophoresis (PFGE) pattern JEGXX01.0004. This is the most common PFGE pattern for SE in the PulseNet database. Investigators are using DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.
In May 2010, CDC identified a nationwide increase in the number of Salmonella Enteritidis isolates with PFGE pattern JEGXX01.0004 uploaded to 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 increase represents approximately a four-fold increase over the expected number of reported isolates of this particular PFGE pattern. Approximately 200 isolates were uploaded to PulseNet on a weekly basis during late June and early July compared to an expected ~50 uploads a week on average during this same period in the previous 5 years. Many states have reported increases of this pattern since May.
Epidemiologic investigations conducted by public health officials in California, Colorado, and Minnesota have revealed several restaurants or events where more than one ill person with the outbreak strain has eaten. Preliminary data suggests that shell eggs are a likely source of infections in many of these restaurants or events. State partners, FDA, and CDC, conducted a traceback and found many of these restaurants or events received shell eggs from a single firm, Wright County Egg, in Galt, Iowa. FDA is currently conducting an extensive investigation at the firm in Iowa. The investigation includes CDC participation and involves sampling, records review and looking for potential sources of contamination, such as feed. The investigation continues and updates will be made available.