MLT 2402 Microbiology I

Gram Positive Cocci

Session Objectives:

By the end of this laboratory session, the student shall be able to:

• Describe the colony and microscopic morphologies of various gram positive cocci
• Perform available biochemical tests on various gram positive cocci
• Follow all safety precautions that should be observed when working with the chemical and biological substances used in this laboratory experience

GRAM POSITIVE COCCI

1. Observe and examine the colonial morphology of the following known cultures on each of the inoculated media:
   • S. aureus
   • S. epidermidis
   • S. saprophyticus
   • Micrococcus spp.
   • S. lugdunensis
2. Prepare smears of each culture and use Gram stain.
3. Examine smears.
4. Perform the following biochemical tests:
   • Catalase
   • Coagulase (Report results on the method used)
   • PYR on S. lugdunensis
5. Determine susceptibility of S. epidermidis and S. saprophyticus to novobiocin disk.
6. Record all results on the laboratory worksheets.

**BE IT NOTED THAT TEST AND MICROORGANISM AVAILABILITY MAY CHANGE.

Note: Due to Covid-19, this exercise will be completed virtually through the use of Google and any other websites listed in the course.