1 . Use of Pulsed - Field Gel Electrophoresis ( PFGE ) for Bordetella pertussis Related Surveillance

There are approximately 1.4 million Salmonella infections annually in the US. PulseNet USA detects multi-state and regional clusters and outbreaks by the use of pulsefield gel electrophoresis (PFGE) of foodborne pathogens, and assists in the investigation of potential common source outbreaks. On July 14, 2004, PA Department of Health noted a cluster of Salmonella Javiana cases in PA involving food from Gas Station Deli Chain A, and notified the PulseNet USA Administration Team. With the use of the PulseNet WebBoard communication tool, PFGE results were posted and rapid responses from nation-wide public health laboratories revealed this to be a multi-state, multi-serotype outbreak. An epidemiological investigation indicated Roma tomatoes from the Gas Station Deli Chain A as the common source of the outbreak. Additional epidemiological investigations and PFGE results confirmed three additional serotypes: Salmonella Anatum, Typhimurium, and Thompson. A number of isolates collected with indistinguishable PFGE patterns continued to be collected until August 2004. Illness onset after the incubation period of Salmonella could be due to factors such as continued Roma tomato use, poor recall, low infectious dose, secondary transmission, or food saved