About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
Sat Apr 21, 2012 1:39 am
I'm currently taking Microbiology and I am working on my unknown. I have narrowed down my unknown to S. Aureus and S. Epidermidis. I suspect that it is S. Aureus because my MSA plate turn yellow after incubation. However, when I did a coagulase test, it resulted in a gelatin like substance (not solid or liquid). Since it is not completely solid, I can't say that it is positive. This contradict my MSA plate because S. Aureus is coagulase positive. I'm not sure what test to believe. I have only done the coagulase test once and I have done the MSA test multiple time. I have picture of my MSA and TSA plate.
Is there anyone who can help me clear this up?
I also have picture of my MSA plate and TSA plate.
Sat Apr 21, 2012 11:18 am
Repeat coagulase and use + and - controls.
Sat Apr 21, 2012 6:24 pm
Any clotting, even if it looks like gel, will be a positive result.
Sun Apr 22, 2012 12:04 pm
Repeat the test with controls. You should expect the appropriate reaction. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC187014/