In this assignment, students will be performing a series of experiments to identify an unknown specimen. It must include the steps to identify the specimen and a report that includes information about

Gram stain

Gram Negative

Gram-negative rods observed, the organism is a Gram-negative bacillus.

All gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermis, Micrococcus luteus, Enterococcus faecalis, Sporosarcina ureae, Corynebacterium xerosis, Bacillus cereus, Bacillus megaterium, Bacillus brevis.)

Phenol Red – Glucose

No color change (broth stayed red): Negative

Negative glucose fermentation: the organism does not ferment glucose.

Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhimurium, Shigella dysenteriae, Serratia marcescens.

Phenol Red – Lactose

No color change (broth stayed red): Negative

Negative lactose fermentation: the organism does not ferment lactose.

None (both remaining organisms are non-lactose fermenters)

Nitrate Reduction Test

Negative – no color change after reagents AND red color after zinc

Nitrate was not reduced; the organism does not use nitrate as a terminal electron acceptor.

Pseudomonas aeruginosa