1. Identification of Unknown Bacteria: individual assignment
Lab 13 Goals and Objectives:
Identification of Unknown Bacteria: individual assignment
Use your data from the 12 possible unknowns for comparison and your Dichotomous Key to solve for your unknown based on the results you collect.
Record results for
MacConkey Agar
Nutrient Gelatin
Decide which collection of media you need next (get approval from instructor or PA) then make new inoculations
From single colonies:
Option A: MSA plate & Rabbit Serum (coagulase)
Option B: BAP (hemolysis) & Bacitracin
Option C: SIM (H2S, Indole, Motility), Citrate, MR & Urea

2. Unknown Identification
Day 1: Each person sign out one unknown
Make streak for isolation on BHIA
Put your name on original slant and return
Day 2: Gram stain
Catalase test
Inoculate MacConkey Agar
Inoculate Gelatin Deep
Day 3: Based on Gram, Gelatinase, Catalase,
Lactose, set up assays to solve:
A. If Staph: MSA and Coagulase
B. If Strep/Entero: BAP and Bacitracin
C. If Gram Neg: SIM, Citrate, MR, Urea

3. Lab 12&13 Lab 12&13 Lab 13 Lab 13 Lab 12 Lab 13 Option A Option B
All 12 Possible Unknowns
Lab 12&13
Lab 12&13
Gram Positive
Gram Negative
Gelatinase +
Gelatinase -
Gelatinase -
Gelatinase +
Lab 13
Lab 13
Lab 12
Lab 13
Catalase +
Catalase -
Lactose +
Lactose -
Option A
Option B
Option C
Mannitol + OR
Coagulase +
Mannitol - OR
Coagulase -
 Hemolytic OR
Bacitracin R
 Hemolytic OR
Bacitracin S
Indole + OR
Citrate -
Indole - OR
Citrate +
H2S + OR
Motile
H2S - OR
Nonmotile
Urea + OR
MR +
VP -
Urea - OR
MR -
VP +
Urea +
Urea -
Staphylococcus epidermidis
Pseudomonas aeruginosa
Staphylococcus aureus
Enterococcus faecalis
Streptococcus pyogenes
Klebsiella pneumoniae
Salmonella typhimurium
Enterobacter cloacae
Bacillus subtilis
Escherichia coli
Proteus vulgaris
Shigella flexneri

4. Identification of Unknown Bacteria: individual assignment
Lab 13 Goals and Objectives:
Identification of Unknown Bacteria: individual assignment
Use your data from the 12 possible unknowns for comparison and your Dichotomous Key to solve for your unknown based on the results you collect.
Record results for
MacConkey Agar
Nutrient Gelatin
Decide which collection of media you need next (get approval from instructor or PA) then make new inoculations
From single colonies:
Option A: MSA plate & Rabbit Serum (coagulase)
Option B: BAP (hemolysis) & Bacitracin
Option C: SIM (H2S, Indole, Motility), Citrate, MR & Urea