Published on 09/11/03

Outbreak of Salmonella berta has experts baffled

By Cat Holmes
University of Georgia

Georgia health officials are searching for the source of an outbreak of Salmonella traced to a Golden Corral restaurant in Kennesaw.

Twenty-three cases of Salmonella berta have been confirmed, said Matthew Daily, a spokesperson for the Cobb County Board of Public Health. The first cases were detected in early June. Over the ensuing weeks, new cases were intermittently confirmed. It wasn't until early August that health officials were alerted to the possibility of an outbreak.

DNA fingerprinting of the cases has confirmed a common cause, Daily said.

Typically, a cluster arises within a short time, said Michael Doyle, director of the University of Georgia Center for Food Safety and an international authority on foodborne bacterial pathogens.

"There is something odd about the fact that this has been going on for over two months," Doyle said. "That suggests it may be an environmental source."

So far, tests of food, the environment and employees at the Golden Corral haven't detected the source of the bacteria.

Investigators spent Wednesday taking food samples and redoing environmental swabbing tests they previously conducted in late August.

Thursday was spent "going over everything with a fine-tooth comb," Daily said. "They're dismantling things and examining gaskets and washers."

Until the source of the outbreak is determined, Daily said, the restaurant will remain closed.

The strain of this outbreak is a very unusual group, or serotype.

More than 2,000 serotypes can cause salmonellosis in humans, according to the Centers for Disease Control. Close to half of the annual cases in the United States are caused by two serotypes: S. enteritidis and S. typhimurium.

Of the 1,400 Salmonellosis cases of reported in Georgia each year, only five to six are typically caused by Salmonella berta, Doyle said.

"It just isn't common," Doyle said. "It's not in the top 10 or even in the top 20."

Salmonella is the most common bacterial source of foodborne illness in the United States, Doyle said. The Centers for Disease Control estimates 1.3 million cases a year, with 500 to 600 of those fatal.

Salmonella is not usually as serious as other foodborne illnesses, and not typically fatal. The person in this outbreak who died had another serious health condition.

Young children, the elderly and people with compromised immune systems are the most likely to have severe infections, Doyle said.

(Cat Holmes is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)

Cat Holmes was a science writer with the University of Georgia College of Agricultural and Environmental Sciences.