This paper proposes Levinea as a new genus within the family Enterobacteriaceae, based on distinctive biochemical and serological properties. The genus comprises two species: Levinea amalonatica (type species, strain ATCC 25405) and Levinea malonatica (strain ATCC 25408). Both species are gram-negative, motile rods with peritrichous flagella isolated from human clinical samples. Key distinguishing features include indole production, positive methyl red test, citrate utilization, and lack of acetylmethylcarbinol and oxidase production. The primary difference between species is that L. amalonatica does not utilize malonate or adonitol, while L. malonatica does. Levinea differs from phenotypically similar genera (Enterobacter and Citrobacter) by its unique biochemical profile, particularly indole production combined with positive methyl red and negative Voges-Proskauer reactions. Serological testing demonstrated no cross-reactivity with major enteric pathogens (Shigella, Salmonella, Escherichia coli, Proteus, Klebsiella) but showed antigenic relatedness between the two Levinea species. The authors named the genus in honor of Max Levine, a prominent enteric bacteriologist.

Key findings

• Levinea is proposed as a new genus of Enterobacteriaceae distinguished by indole production, positive methyl red test, and negative Voges-Proskauer reaction, differentiating it from similar genera Enterobacter and Citrobacter
• Two species are described: L. amalonatica (malonate-negative) and L. malonatica (malonate-positive), with consistent biochemical profiles across multiple strains
• Serological testing confirmed no antigenic relationship to major enteric pathogens but demonstrated cross-reactivity between the two Levinea species
• 108 strains were isolated from human clinical samples, primarily from fecal specimens, establishing this as a clinically relevant bacterium
• The new genus differs fundamentally from existing Enterobacteriaceae in requiring redefinition of generic characteristics rather than expanding existing genera