By controlling what enters and leaves a cell, the cell membrane A) aids in maintaining homeostasis within the cell. Homeostasis is the process by which organisms maintain life through eating, growing, and living in variable conditions. It would not make sense to answer B) because organisms do not control the homeostasis of their external environment. D) also would not be correct because cell's do not control osmosis in the external environment. The membrane does not control osmosis because osmosis is generally a random process of molecular diffusion whereas the membrane acts in a conscious and controlled way.
Answer:
You are interested in obtaining Staphylococcus aureus for a study investigating the prevalence of methicillin-resistant Staphylococcus aureus in the general population. You have received several samples and are ready to start your isolation procedures. Describe the personal protective equipment that would be needed and three different culturing techniques that can be used to obtain organisms to produce pure cultures. State if you use general or selective media and which specific media you would choose. How would you determine if the culture was contaminated? What is the first step you would take if you detected contamination?
Personal Protective equipment needed; No special precautions are necessary when working with methicillin-resistant staphylococcus aureus, staphylococcus aureus is a bio-safety level
Three different culturing media; to include;
- Etest Method
- Disc Diffusion
- Latex Agglutination.
Properly enriched selective media is used.
The most accurate method for identifying Merthicillin-resistant staphylococcus is to test for the presence of mecA gene by PCR.
The best specific media is latex agglutination test and oxacillin salt agar screen.
How to determine if the culture was contaminated;
It can be spotted by the turbidity of the growth medium or the floating branching mycelia, bacteria contamination can be detected under 10× microscope within few days of contamination.
Step to take if contamination is detected;
Biological contamination is a serious issue and being able to correctly identify different types of contamination is an essential first step in ensuring the safety of your culture.
Explanation:
The literature on methicillin susceptible testing is extensive, and often conflicting in recommendations regarding the most important method for routine use. this is partly because the various studies of phenotypic methods have included different strains, which may differ significantly in heterogeneity and behave differently under particular test condition.
