The strains differ with respect to arginine dihydrolase, saccharose, raffinose, inositol, and ribitol metabolism,where EcO55 shows a positive reaction,while EcNis negative. EcN, in contrast, exhibits arginine dihydrolase activity,which is absent in EcO55. Thismetabolic profile represents the pure cultures of the two strains fromour strain collection (not themetabolic profile of the picked single colonies).