Molecular differentiation of <i>Escherichia coli</i> O157:H7 and Shigella using 16s rRNA phylogeny

Abstract

Background: Differentiation of E. coli O157:H7 from Shigella is reported to be difficult. Resource-poor settings rarely report on this or the percentage of  E. coli O157:H7 that will cluster around Shigella in a phylogenic tree.

Aim: This study aimed to differentiate between E. coli O157:H7 and Shigella using 16S rRNA phylogeny.

Method: A total of 7 non-sorbitol fermenting E. coli of which 5 have been confirmed serologically as E. coli O157:H7, were used for this study.  Amplification of hypervariable region of the 16S rRNA in these isolates followed by phylogenic analysis of the sequences was carried out for all the isolates.

Results: Only one isolate clustered around Shigella boydii while the others clustered around E.coli. Twenty percent of the E. coli O157:H7 clustered around  Shigella.

Conclusion: The use of 16S rRNA appears to be a good and veritable tool for differentiating the two genera.