using sequences of single-copy housekeeping gene regions, 
which are used in multilocus sequence analysis in the ab-
sence of sufficient available whole genome sequences.In ad-
dition, a deoxyribonucleic acid (DNA)-DNA hybridization 
cut-off of 70% or greater for species identification and an 
average nucleotide identity of 95% or greater has also been 
used for speciation within the Enterobacteriaceae.Furthermore, except for Shigella 
dysenteriae type 1, all commonly isolated Enterobacteriaceae
are catalase positive.Epidemiology
Enterobacteriaceae inhabit a wide variety of niches