Persistent endemicity of Salmonella bongori 48:z(35):--in Southern Italy: molecular characterization of human, animal, and environmental isolates

Abstract

From 1984 to 1999, we collected 31 isolates of the rare serovar Salmonella bongori 48:z(35):- in southern Italy. Twenty-four of the isolates were from cases of acute enteritis in humans. Pulsed-field gel electrophoresis analysis showed that all but one of our isolates were at least 80% similar. Our findings suggest that genetically related S. bongori 48:z(35):- strains are endemically circulating in southern Italy.

FIG. 1.

PFGE restriction patterns of nine representative S. bongori 48:z₃₅:− isolates from Sicily and Calabria and two collection strains from Chad and England. Lanes 1 and 15, lambda ladder pulsed-field gel (PFG) marker 340 (New England Biolabs, Inc., Beverly, Mass.); lanes 2 and 14, low-range PFG marker 350 (New England Biolabs); lane 3, CIP 261-66 (Chad); lane 4, CIP 5040-85 (United Kingdom); lane 5, C 285 CT 85; lane 6, CEIM 24662 ME 85; lane 7, CEIM 26851 ME 85; lane 8, C 634 CT 98; lane 9, CEIM 44721 RG 98; lane 10, CEIM 46162 RG 99; lane 11, CEIM 46295 PA 99; lane 12, CEIM 46049 AG 99; lane 13, CEIM 46082 CS 99. The two-digit numbers after the city abbreviation (see Table 1, footnote b) indicate the year of isolation.

FIG. 2.

Dendrogram showing percent similarity calculated by the Dice similarity index of PFGE restriction endonuclease digestion profiles among the 31 S. bongori 48:z₃₅:− isolates from southern Italy and two collection strains from Chad (CIP 261-66) and England (CIP 5040-85).