Summary: The phenotypic and genotypic characteristics of 69 wild-type strains of from Sardinia and other Italian regions, representing four different epidemic outbreaks, were studied. Biochemical profiles, pathogenicity factors, resistance to antibacterial drugs and genomic organization were investigated. None of the strains tested showed any haemagglutination with different types of red blood cells, and electron microscopy revealed no fimbriae. Adhesivity to epithelial cells was present in all strains tested. Only 16% of the strains were resistant to streptomycin, and no other drug resistances were found. The restriction patterns of chromosomal DNA did not show heterogeneity and a high-molecular-mass (50-67 kb) plasmid was found in all strains. Restriction analysis of plasmid DNA from strains from different geographical areas, collected over a period of 30 years, showed a III restriction profile characterized by two patterns, one with three fragments, stable and common to all strains, and a second polymorphic pattern with five fragments. The stable pattern included a 3·7 kb dIII fragment that hybridized with a probe containing a virulence region including the and genes. These studies allowed us to outline a genetic correlation among isolated from different outbreaks.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error