Distribution of Salmonella typhi and Salmonella paratyphi B phage types in Italy from 1974 through 1985.

The temporal changes in occurrence and distribution in Salmonella typhi and paratyphi B phage types in Italy during a twelve year period are considered. From 1974 to 1985, 2.075 isolates of Salmonella typhi and 830 isolates of Salmonella paratyphi B were phage typed at the National Centre for Enterobacteria in Rome and the three Regional Centres for Enterobacteria in Milan, Palermo and Pisa. The most prevalent types of Salmonella typhi were A, C1, D1, Vi degraded strains E1, I+IV and C4. Types A, C1 and D1 accounted for 59.1% of the total. The distribution of the phage types as A, B2, C1, D1, D4, D9, E1, F1, N, 28 and I+IV, Vi degraded and Vi negative strains in the three time periods (1974-77; 1978-81 and 1982-85) was quite similar; some types such as D8, E2, 0 and 43 were found sporadically and others like C9, D6, F4, H and 45 which were present in the first period, disappeared in the last. The most prevalent types of Salmonella paratyphi B were Tauton, Dundee, 1, and 3a. Type 2, frequently found in the 1974-77 period was however not seen during 1981-85.