Clonal structure of Providencia alcalifaciens strains isolated from diarrhoeal stools in Sao Paulo, Brazil

Clonal analysis based on ribotyping demonstrated that Providencia alcalifac iens strains isolated mainly from diarrhoeal stools in S (a) over tilde o P aulo, Brazil, were clustered into two main groups. Eleven distinct ribotype patterns were identified with ClaI, EcoRV and MluI restriction endonucleas es. II alcalifaciens strains with invasive properties were of two ribotype patterns that differed from those identified among non-invasive strains. Th e ribotyping results confirmed that P. alcalifaciens strains associated wit h diarrhoeal disease in S (a) over tilde o Paulo represent distinct groups of strains. Although the invasive strains were isolated from different pati ents over an extended period they were clustered into two genetically relat ed clones, which seemed to be distributed endemically in the two geneticall y related population studied.