A biotype of Enterobacteriaceae intermediate between Citrobacter and Enterobacter.

The authors isolated two strains of an unnamed bacterial biotype with characteristics intermediate between those of Enterobacter and Citrobacter. The organisms did not produce acetyl-methyl carbinol, but decarboxylated lysine. Apart from the latter trait, they most closely resemble H2S-negative Citrobacter freundii. They differ biochemically from all other currently accepted species of enterobacteriaceae. Their pathogenic significance appears similar to that of the two genera they most closely resemble. Only by recognition and study of additional strains can their identity be more definitively delineated and their significance more fully assessed.