RESUMEN
This paper describes outbreaks of Salmonella Typhimurium phage type 197 (STm197) linked to eggs from the farm of a single egg producer. Epidemiological and microbiological investigations (genotyping by multiple locus variable number tandem repeats analysis [MLVA]) identified outbreaks of STm197 with the same or closely-related MLVA profiles in a series of restaurants across Brisbane over 2 months. Environmental health investigations revealed that these restaurants were supplied with eggs from the same egg producer and that cross-contamination may have contributed to the outbreak. Environmental swabs taken from restaurant kitchens and the farm of the egg producer identified a number of salmonellas including STm197, many with MLVA profiles matching or closely related to the human strains from outbreak cases. A case-to-case comparison study showed a significant association between illness with 1 MLVA type and attending a restaurant during the 5 days before onset of illness (odds ratio [OR] 8.1, 95% confidence interval [CI] 1.8, 35.4). MLVA has become a valuable tool for S. Typhimurium surveillance and outbreak investigation. This outbreak further justifies the Commonwealth Government's decision to develop a draft national primary production and processing standard for eggs and egg products to address food safety risks posed by cracked and dirty eggs.