BIOCHEMICAL STUDY OF PROTEUS INCONSTANS (PROVIDENCIA).

The biochemical reactions of 8 isolates of Proteus inconstans biotype A, 83 isolates of P. inconstans biotype B and 18 isolates of P. rettgeri were compared with 14 isolates that had the same biochemical pattern as biotype B of P. inconstans but for a positive urease reaction. On the basis of comparison it is shown that the atypical isolates must be considered as urease positive variants of P. inconstans biotype B. The urease reaction is accordingly not an absolutely reliable feature in differentiating P. inconstans from the other Proteus species. This confirms the observations of some previous authors but contradicts the more generally accepted view. Attention is drawn to the possible value of a negative galactose fermentation test in characterizing strains of P. inconstans biotype A.