BIO488L: Medical Microbiology Lab Exercise 4

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BIO488L Medical Microbiology Lab Exercise 4

• Spring 2006
• T.A. Sami Kemper

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Today

• Quiz 2
• Staphylococcus and Streptococcus Lab
• You will need to check these cultures several
  times this week!
• Continue Identification of Clinical Unknowns
• Enterobacteriaceae unknown paper due today
• Staph/Strep paper due next week

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Staphylococcus

• Part of the normal flora of the skin and mucosa
• Wound infections, food poisoning, TSS
• MRSA
• Staph. Aureus and Staph. epidermidis

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Tests

• Coagulase test from Stph Ident kit
• Innoculate BEA, BAP, MSA and TSA
• ½ plates for known cultures
• 1 plate for personal sample (nose, skin or throat
• Choose 1 colony from personal swab tomorrow to
  innoculate on BAP, check at 24 hrs and perform
  Gram stain plus catalase and oxidase tests

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Streptococcus

• Part of the normal skin and mucosal flora
• Streptococcal pharyngitis, scarlet fever,
  rheumatic fever, neonatal sepsis, and necrotizing
  fascitis
• Strep. agalactiae, Strep. faecalis, and Strep.
  pyogenes

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Tests

• Same procedure as for Staph. Except we sill be
  using a Streptococcal Grouping kit to determine
  the Lancefiled group of each species.

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• MSA- Mannitol Salt Agar
• Selective for Staphylococcus
• Staphylococcus aureus ferments mannitol to
  produce golden colonies with yellow zones

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• BEA Bile Esculin Agar
• Group D streptococci and Enterococcus spp. can
  hydrolyze esculin to produce esculetin and forms
  a brown/black precipitate

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• BAP Blood Agar
• Test for a and b hemolysis
• Grow fastidious organisms

b
a
b