Lab 6 - Gram Positive Cocci IN CLASS

Gram Positive Cocci Lab Case Study Hannah is a 17 year old female who was feeling fine until 2 days ago, when she started vomiting and had a fever of 101F. This morning she continued vomiting and noticed a strange blistering rash on her abdomen. It looked like a sunburn, but she hadn’t been out in the sun. She went to her doctor’s office, where her blood pressure was found to be 78/46 (hypotensive). Her heart rate was 120 beats per minute and her temperature was still 101F. Hannah was transported to the ER. Upon admission, the ER noted that Hannah seemed confused and was breathing rapidly. She was found to have a high white blood cell count, an indication of infection. She was given IV fluids and antibiotics, and a culture was taken for microbial analysis. Hannah was diagnosed with Toxic Shock Syndrome. Her last menstrual period started 3 days before she became sick. In this lab, you will perform further tests on this bacterial culture to determine what species of bacteria is responsible for Hannah’s infection. Lab Report to Turn in Results Part A – Catalase Test Toxic Shock Syndrome can be caused by both Staphylococcus and Streptococcus . Perform a catalase test to determine which genus caused Hannah’s infection. Fill out the table below. Bubbles observed? Catalase Positive or Negative? Interpretation ( Staphylococcus or Streptococcus ?) Yes Positive staphy Part B – Hemolysis Test Inoculate the blood agar with Hannah’s unknown bacteria + Bacillus subtilus . After incubation, fill out the table below. Did the bacteria grow? Type of hemolysis Bacillus subtilis yes gamma Hannah’s “Unknown” yes beta

Part C - MSA Inoculate Mannitol Salt Agar with Hannah’s unknown bacteria + Bacillus subtilus . After incubation, fill out the table below: Did the bacteria grow on MSA agar? Is the bacteria halotolerant? Color observed around bacterial growth? (if applicable) Can the bacteria ferment mannitol? (if applicable) Bacillus subtilus yes yes Light Yellow Yes Hannah’s “unknown” yes Yes Yes Orange Yes Part D Use the table below to determine the identity of the bacteria. Staphylococcus aureus Staphylococcus epidermidis Streptococcus pneumoniae Streptococcus pyogenes Catalase test Positive Positive Negative Negative Hemolysis Beta Gamma Alpha Beta Growth on media containing 7.5% NaCl Yes Yes No No Mannitol fermentation Yes No No No Which species caused Hannah’s infection? Staphylococcus aureus