Diagnostic potential of sefA DNA probes to Salmonella enteritidis and certain other O-serogroup D1 Salmonella serovars.

Salmonella enteritidis thin fimbriae, SEF14, were found to be restricted to S. dublin and the predominantly poultry-associated members of the Salmonella O-serogroup D1, S. enteritidis, S. berta, S. gallinarum and S. pullorum, when tested by Western and ELISA analysis from among 90 Salmonella isolates of 42 serovars, as well as from members of several related genera of the Enterobacteriaceae. These five serovars and a single isolate of S. typhi (D1) were also detected by hybridization of genomic DNA from 732 Salmonella isolates of 117 serogroups to gene probes derived from the S. enteritidis sefA (fimbrin gene), sefB (chaperone) or sefC (outer membrane protein) genes encoding proteins involved in SEF14 biosynthesis. None of 250 Enterobacteriaceae or 27 other eubacterial isolates tested hybridized to the sef probes. The sefA, sefB and sefC genes were amplified from these six Salmonella serovars by PCR using primer pairs designed from sefA, sefB or sefC of S. enteritidis. DNA sequencing of sefA genes from these five serovars indicated limited sequence variability among sefA genes and recognition of individual base pairs which could potentially differentiate certain strains of S. enteritidis, S. dublin and S. gallinarum.