Abstract: The invention relates to methods of detection of bacteria of the genus Shigella and/or Enteroinvasive E. coli (EIEC) by use of a set of nucleic acid probes. The invention further relates to a set of Shigella specific chromosomal sequences and fragments and to probes derived from the Shigella specific fragments. Additionally, probes were derived from a sequence from the Shigella ompA gene. In particular, a series of probes, each approximately 40 nucleotides in length, were designed having specificity for Shigella or for Shigella and Enteroinvasive E. coli, and having utility in non-isotopic test formats which require amplification to achieve high sensitivity. Specific hybridization probe sets which are capable of detecting substantially all clinically significant serotypes of Shigella, as well as enteroinvasive strains of E. coli, are disclosed.