Lab Exercise 14: Biochemical Differentiation of some Medically Important Gram Positive Cocci

Beta ( ) hemolysis (blood agar around bacterial colonies is completely clear, indicating complete breakdown and consumption of hemoglobin)

Alpha () hemolysis (blood agar around bacterial colonies looks greenish-brown, indicating partial breakdown and consumption of hemoglobin)Mixed culture from a throat swab; note several -hemolytic colonies

Gamma () hemolysis (really means no hemolysis; blood agar around colonies looks normal)

Side-by-side comparisons of alpha (), beta (), and gamma () hemolysis

Bacitracin (Taxo A) sensitivity + results with a zone of inhibition

Coagulase Test+-

Carbohydrate Fermentation Tests (Glucose and Mannitol)+- (same as uninoculated media)Phenol red indicator turns yellow at acid pH

Catalase Test

Use the chart on p. 146 and/or the flow chart on p. 147 of your lab manual to figure out who I am!Answer: Streptococcus pyogenes

G MUse the chart on p. 146 and/or the flow chart on p. 147 of your lab manual to figure out who I am!Answer: Micrococcus lutea

Use the chart on p. 146 and/or the flow chart on p. 147 of your lab manual to figure out who I am!AAnswer: Enterococcus faecalis

Answer: Staphylococcus aureus

Use the chart on p. 146 and/or the flow chart on p. 147 of your lab manual to figure out who I am!Answer: Staphylococcus epidermidis

Use the chart on p. 146 and or the flow chart on p. 147 of your lab manual to figure out who I am!Answer: Streptococcus pneumoniae

Use the chart on p. 146 and/or the flow chart on p. 147 of your lab manual to figure out who I am!AAnswer: Streptococcus mutans

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