TABLE 1.

Biochemical testing of environmental E. coli isolates with the API 20E biochemical test strip

Enzymatic testbTest resulta for isolate:
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β-Galactosidase (ONPG)+++++++
Arginine dihydrolase (ADH)
Lysine decarboxylase (LDC)+++++++
Ornithine decarboxylase (ODC)+++
Citrate utilization (CIT)
H2S production (H2S)
Urease (URE)
Tryptophan deaminase (TDA)
Indole production (IND)+++++++
Acetoin production (VP)
Gelatinase (GEL)
Fermentation/oxidation of:
    Glucose (GLU)+++++++
    Mannitol (MAN)+++++++
    Inositol (INO)
    Sorbitol (SOR)++++++
    Rhamnose (RHA)+++++++
    Saccharose (SAC)+++
    Melibiose (MEL)+++++++
    Amygdalin (AMY)+
    Arabinose (ARA)+++++++
Cytochrome oxidase (OX)
Nitrate reduction (GLU)+++NTNTNT+
  • a +, positive result; −, negative result; NT, not tested. Results are given in boldface when they differ for different isolates.

  • b Biochemical test, with letters in parentheses representing the respective reaction/enzyme.