BIOCHEMICAL TESTING: ENTEROBACTERIACEAE

All Enterobacteriaceae spp. are Oxidase negative except:

• Plesiomonas shigelloides
• Shigella dysenteriae
• Erwinia
• Pantoea agglomerans

All Enterobacteriaceae spp. are Catalase positive except:

• Plesiomonas shigelloides
• Shigella dysenteriae
• Erwinia
• Pantoea agglomerans

All Enterobacteriaceae spp. reduce nitrate to nitrite except:

• Plesiomonas shigelloides
• Shigella dysenteriae
• Erwinia
• Pantoea agglomerans

Principle/purpose: Detects the presence of cytochrome oxidase

• Oxidase test
• Nitrate reduction
• ONPG test
• Oxidation/Fermentation (Hugh-Leifson) test

Principle/purpose: Detects the presence of nitrate reductase/nitrosoreductase.

• Oxidase test
• Nitrate reduction
• ONPG test
• Oxidation/Fermentation (Hugh-Leifson) test

Principle/purpose: Detects the presence of β-galactosidase. Determines the presence of late and slow lactose - fermenting strains

• Oxidase test
• Nitrate reduction
• ONPG test
• Oxidation/Fermentation (Hugh-Leifson) test

Principle/purpose: Determines whether an organism utilizes carbohydrates anaerobically (fermentation) or aerobically (oxidation)

• Oxidase test
• Nitrate reduction
• ONPG test
• Oxidation/Fermentation (Hugh-Leifson) test

Oxidase test Reagent

• Tetramethyl-p-phenylenediaminedihydrochloride
• p-Aminodimethylanilineoxalate
• Tetramethyl-p-phenylenediaminedihydrochloride w/ tetramethyl sulfoxide

Oxidase test Reagent

• Tetramethyl-p-phenylenediaminedihydrochloride
• p-Aminodimethylanilineoxalate
• Tetramethyl-p-phenylenediaminedihydrochloride w/ tetramethyl sulfoxide

Oxidase test: Development of dark purple color within 10s [ Indophenol (purple)]

• POSITIVE
• NEGATIVE