Learning Objectives:

• Explain how and why microbial colonization occurs.
• Recognize potential sources of contamination.
• Describe the consequences of unregulated population growth.
• Describe the ideal environments for microbial growth and how they can be manipulated.
• Appreciate different levels of selective toxicity.
• Describe modes of microorganism growth control.
• Define selective toxicity and what it means for host organisms.
• Differentiate between disinfectants, antiseptics, and antimicrobials.
• Explain the utility of antimicrobial agents.
• Appreciate why different antimicrobials are effective against different infections.
• Select an appropriate antimicrobial to target a given microorganism.

Compare the effectiveness of different antimicrobial compounds

SOLUTION

One method of determining chemical effectiveness is the disk-diffusion method, also called diffusion disc method in the simulation. This method involves adding chemicals to small disks of filter paper and then applying them to agar plates inoculated with bacteria. The filter paper absorbs the chemical, which diffuses out into the agar. The concentration of the chemical decreases with its distance from the disk. If the concentration of the chemical is sufficient to inhibit bacterial growth, then agar in that region remains clear. The surrounding agar becomes overgrown with a covering of bacteria (called a bacterial lawn).….Please click the icon below to access entire solution at $10