These findings were confirmed by Szturm-Rubinsten et al. (13) in 1962. Based on these data and on the fact that
Shigella firexneri 6 biovars can also be aerogenic (2, 3), these authors proposed that “Enterobac- terium A12” should be regarded as an aerogenic biovar of S. boydii 14. However, in 1972 Edwards and Ewing (3) stated that the microrganisms
designated by Sachs as “Enterobacterium A12” should not be regarded as possible members of the genus Shigella because they were aerogenic and utilized citrate mutatively in Christensen citrate agar medium and because some strains
showed mutative fermentation of lactose.