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Characterization of rpoS alleles in Escherichia coli O157:H7 and in other E. coli serotypes
Author(s) -
Ferreira A.,
Rendano L.,
Wiedmann M.,
Boor K. J.
Publication year - 1999
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1999.00664.x
Subject(s) - escherichia coli , rpos , biology , enterobacteriaceae , serotype , microbiology and biotechnology , bacteria , nucleic acid sequence , peptide sequence , sequence analysis , genetics , gene , promoter , gene expression
The rpoS nucleotide and predicted amino acid sequences from three Escherichia coli O157:H7 isolates were compared with those from three other E. coli isolates, including the likely O157:H7 progenitor, E. coli O55:H7. These clinical and environmental isolates all had identical σ S amino acid sequences, while laboratory strains K12 and DH1 had three and one amino acid alterations, respectively, in comparison with the majority sequence. To extend the analysis of σ S sequence conservation to include other Gram‐negative bacteria, the E. coli σ S sequences were compared with those from diverse Gram‐negative organisms; σ S sequence identities ranged from 50·2 to 99·7% among the available sequences. The results further confirm the existence of rpoS alleles among different E. coli strains, although all strains were classified as acid‐resistant with survival rates >10% after 2 h exposure to pH 2·5. It was also found that all E. coli O157:H7 isolates tested had a unique nucleotide at position 543, thus differentiating these strains from other E. coli serotypes.