microbio quiz #4: eye eye eye and shark

gram reaction of associated bacteria

eye

• Pseudomonas aeruginosa

shark

• vibrio algunolyticus

• v. fluvialis

• v. parahaemolyticus

media used in each case study

eye

• media used: cetrimide

• what are you looking for, selecting for?

  • selective for Ps. aeruginosa

• how does it work?

  • the media disrupts nitrogen and phosphorus levels in other bacteria

  • either kills the bacteria or slows growth

shark

• media used: MSA (red) and TCBS (green)

• MSA

  • Mannitol Sugar Agar

  • selective AND differential

  • the differential agent in MSA is mannitol

    • G(-) non-mannitol —> media stays red

      • ex) Staph. epidermus

    • G(+) mannitol cons. —> yellow

      • Staph. aureus

• TCBS

  • Thiosulfate, Citrate, Bile-salt, Sucrose, Agar

  • selective and differential for Vibrio spp.

    • vibrio chlorae

    • vibrio parahaemolyticus

virulence factors of bacteria

• Pseudomonas aeruginosa:

  • biofilm

  • motility (flagella/pili)

  • antibiotic resistant

  • opportunistic pathogen: cause infections in immunocompromised individs.

• Vibrio algunolyticus

  • adhesion molecules (capsule)

  • extracellular products (hemolysins)

• V. fluvialis

  • hemolysins

  • protease

• V. parahaemolyticus

  • hemolysis

  • cytotoxicity

vibrio bacteria

• what is it abt this bacteria that allows it to live in an oceanlike environ?

• —> gram positive and halophile so loves salt, saltwater