1. Identification of Strep and Staph and Isolating gram – pathogens Lab # 10 Medgar Evers College Prof. Santos

2. Exercise 70 Isolation of Staphyloccocus aureus from three sources, fomite, nose and a given culture. There are some properties you need to know beforehand –Gram positive spherical bacteria that divide in more than one plain to form irregular clusters. –When grown in trypticase soy agar or blood agar the colonies are 1 to 3 mm in diameter. –The colonies may be yellow, orange or white. –they are coagulase positive meaning they can clot serum –they produce alpha toxin to yield a clear zone of beta hemolysis in blood agar plate –ferment mannitol sugar to produce acid –Are salt tolerant.

3. Know the chart of the three different species of Staphylococcus and their properties. S. aureusS. epidermidisS.saprophyticus Alpha toxin+-- Mannitol+-Mostly + Coagulase+-- Biotin for growth-+Not significant Novobiocinsensitive resistant

4. Week 1 Inoculate three tubes of Staphylococcus broth. One from a culture of Staph One from a fomite One from your nose using a sterile cotton swab!

5. Exercise 71 The main objective here is to isolate Streptococci and characterize them based on certain properties. Pretty much you need to be able to identify them according to Lancefield group, A, B, C, D or none. Know the table in your book! Know 2 differences between the Staphylococci and Streptococci.

6. 2 differences 1- Staph grows in clusters and Strep grows in chains.

7. 2- Streptococcus are catalase negative and Staphylococcus are catalase positive.

8. Week 1 Isolate Strep from your throat using a sterile cotton swab and tongue depressor. Swab the back of your throat and inoculate a blood agar plate.