A foodborne outbreak of Salmonella Enteritidis phage type 6 in Austria, 2008.

In April 2008, a general foodborne outbreak of Salmonella Enteritidis phage type 6 affected nine persons (two households in Salzburg and one household in Tyrol; eight microbiologically confirmed cases and one possible case). Epidemiological investigation revealed that all cases had eaten lunch together at a farm. Homemade bread dumpling loaf, prepared with eggs from the farm, was the most likely vehicle for the pathogen. Six eggs were bacteriologically tested and yielded the outbreak strain on the egg shells. The farm's egg laying flock consisted of 12 hens, which were identified as the source of infection by isolating the outbreak strain from samples of hen fecal material and dust. Molecular subtyping using multiple loci variable number of tandem repeats analysis (MLVA) revealed a pattern unique to isolates from the outbreak, different from nine epidemiologically unrelated isolates tested for comparison. The laying hens were culled and no further cases of salmonellosis were associated with the farm. This example demonstrates the considerable potential of outbreak investigation to elucidate the transmission of infection along the food chain and to provide information essential for implementation of targeted measures for prevention of foodborne illness.