a1 Laboratory of Immunology, Istituto Superiors di Sanità, Rome, Italy
a2 Laboratory of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, Rome, Italy
This report summarizes studies on 1699 foodborne outbreaks, in Italy, reported to the Istituto 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 by Salmonella enteritidis and 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 to S. enteritidis (50 outbreaks), S. typhimurium (three outbreaks) and S. hadar (one outbreak). In the S. enteritidis outbreaks, 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 of S. enteritidis.
(Accepted January 08 1996)
c1 Correspondence and requests for reprints: Dr Gabriella Scuderi, Laboratorio di Epidemiologia e Biostatistica, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.