DISTINGUISHING FEATURES OF SPECIES IN GENUS

Question 1

Streptococcus pyogenes vs Streptococcus agalactiae.

Answer 1

Streptolysin O present in S.pyogenes samples, not in S.agalactiae.

S. pyogenes is bacitracin sensitive.

S. agalactiae is bacitracin resistant

Question 2

Differentiating Strep A strains.

Answer 2

M and T antigen tests.

Question 3

Salmonella serotyping.

Answer 3

Based on ‘O’ somatic and ‘H’ flagellar antigens.

Question 4

Neisseria meningitidis serotyping.

Answer 4

Based on cell wall proteins.

Question 5

Yersinia pestis and other Yersinia species

Answer 5

Y. pestis is urease negative

Question 6

What is one way you can differentiate Clostridium difficile, Clostridium tetani and Clostridium botulinum?

Answer 6

Clostridium botulinum has subterminal or terminal spores, whereas tetanus and difficile have terminal spores.

C. botulinum can however display terminal spores, despite subterminal spores being more common.