Gram Stain

Gram Negative (-ve)

Morphology?

Bacillus

Ferments Lactose?

Yes

Liquefies Gelatin?

Negative

Coagulase Test?

Negative

E. coli

Positive

Positive

No

Liquefies Gelatin?

Positive

Coagulase Test?

Negative

P. aeruginosa

Postive

Negative

Coccus

Gram Positive (+ve)

Morphology?

Coccus

Ferments Lactose?

Yes

Liquefies Gelatin?

Positive

Coagulase Test?

Positive

S. aureus

Negative

Negative

Coagulase Test?

Negative

S. epidermidis

Positive

No

Bacillus