Foodborne outbreaks caused by salmonella in Italy, 1991–4

Abstract

SUMMARY: This report summarizes studies on 1699 foodborne outbreaks, in Italy, reported to theIstituto Superiore di Sanità(ISS) (the National Institute of Health of Italy, Rome) during the period 1991–4. The most frequently reported foodborne outbreaks were caused by salmonellae (81%), in particular bySalmonella enteritidisand non-serotyped group D salmonella (34% and 33% of the total salmonella outbreaks, respectively). A vehicle was implicated in 69% of the salmonella outbreaks; eggs were implicated in 77% of the outbreaks for which a vehicle was identified or suspected. Salmonella strains isolated in 54 outbreaks were studied for phenotypic and genotypic characteristics. The isolates belonged toS. enteritidis(50 outbreaks),S. typhimurium(three outbreaks) andS. hadar(one outbreak). In theS. enteritidisoutbreaks, phage type 4 was most frequently isolated (64·8%), followed by phage type 1 (14·8%). The virulence plasmid of 38 megadaltons was found in many different phage types ofS. enteritidis.