Assignment
1.2.1 Antibiotic Therapy - 2023
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University:
University of Arizona -
Course:
NSC 310 | Principles of Human Nutrition in Health and Disease Academic year:
2023
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Views:
0
Pages:
12
Author:
customer-8003159
Specific antibiotics are effective at preventing the growth of certain strains
of bacteria. The effectiveness of antibiotics is dependent on the mechanism
of action of the drug and the structure of the bacteria. For example, certain
antibiotics are effective against Gram-negative bacteria; whereas, other
antibiotics are effective against Gram-positive bacteria. Now that Sue Smith
has been diagnosed with a Neisseria meningitidis bacterial infection, her
doctor needs to prescribe the correct antibiotic to treat her infection and
save her life.
In this activity, you will review bacterial structure, investigate various types
of antibiotics and their mode of action against the bacteria they target, and
suggest an antibiotic treatment for Sue Smith.
HISTORICAL HIGHLIGHT
Hans Christian Gram
In 1884, while examining lung tissue from patients who had
died of pneumonia, a microbiologist named Hans Christian
Gram (Figure 1) discovered that certain stains were
preferentially taken up and retained by bacterial cells. But
Gram did not use a counterstain in his procedure.
It was a few years later, when the German pathologist Carl
Weigert (1845–1904) from Frankfurt, added a final step of
staining cells with safranin. Gram himself never used the red
counterstaining to visualize the gram negative bacteria.
Today, the Gram stain technique remains one of the first steps
in classifying or identifying bacteria.
1 ● Computer with internet access
Procedure
Review the structure of a bacterial cell. Refer to Figure 1 and consult
additional websites if desired.
Describe the function for each structure or component in the table
below.
Structure
Function
Nucleoid
It controls the function and reproduction of the cell
Plasmid
Carry genes for replicating
Ribosomes
Site of protein synthesis
Cell wall
Provides protection and support
Plasma membrane
(cell membrane)
Provides protection for the cell and provides a fixed
environment for the cell
Capsule
Protects bacteria from harmful compounds
Flagella
Allows movement and motion
Pili
Allows it to attach to something
Endotoxins
Establishes a barrier that is permeable only to
2 certain things
Research the difference in cell wall structure between a Gram-positive
and Gram-negative bacteria. Take notes in the space below. Alternatively
you may create a graphic organizer and upload the image in the space
below.
Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall.
Gram-positive bacteria do not have an outer membrane but are
surrounded by layers of peptidoglycan thicker than gram-negative.
In the space below, record some of the ways antibiotics may work to
kill bacteria without harming human cells.
Antibiotics can restrict the ability for cells from building a cell wall, since
human cells do not have cell walls.
Work with your partner to research how your assigned class of
antibiotics affects and destroys bacteria. Create a poster characterizing your
antibiotic class using the guidelines below. Complete the chart below as each
group presents their information. You may insert pictures of each
presentation instead of typing out your responses. You must include
common names of the antibiotics, what types of bacteria they work on, how
they work [mechanisms of action] and what diseases they are commonly
used to treat. Be sure to include any significant side-effects or
contraindications for using your assigned type of antibiotic.
Antibiotic Class
Information
3 Penicillins [β-Lactams]
Tetracyclines
4 Fluoroquinolones
5 Sulfa [Sulfonamides]
6 Macrolides
7 Aminoglycosides
8 Cephalosporins
Carbapenems
9 Glycopeptides/
Lipoglycopeptides
Oxazolidinones
Ansamycins
Streptogramins
10 Research the structure of Neisseria meningitidis bacteria and
characterize it. Place notes in the space below. Also determine if it is a
Gram-positive or Gram-negative bacteria.
Neisseria meningitidis is gram negative. It is a cocci and encapsulated.
Answer the Conclusion questions.
Research Associate
Meet Rachel Engler, a research associate who tests newly
developed pharmaceuticals against a wide range of infectious
diseases. Watch the Life in a Lab video to see Rachel take you
through a day in the lab and explain why her work from the bench
supports frontline practitioners.
1. What cellular components do some bacterial cells have that make
them powerful pathogens? Explain your answer.
The pili allows the bacteria to attach to the host tightly.
2. Why are penicillins often more effective against Gram-positive bacteria
than Gram-negative bacteria?
It is easier to reach the cell wall in a gram-positive because it has a weaker
cell wall.
3. Why is it important to understand the structure of a bacterial cell when
developing an antibiotic?
11 It is important because we need to know which proteins and enzymes
create them and we can know which chemicals can kill them.
4. How do antibiotics work without harming the surrounding human cells?
They affect things that bacterial cells have, like cell walls, that human cells
do not.
5. What class of antibiotics would you prescribe for Sue? Explain your
answer.
I would use the sulfa antibiotics because the bacteria is gram-negative,
and the sulfa drugs would destroy bacteria.
6. Why are antibiotics NOT effective against viruses? (Think back to what
you learned about viruses in PBS.)
Viruses do not have a cell wall that can be attacked by antibiotics like
bacteria can.
7. Identify the differences between a gram+ and gram- bacteria cell.
Explain how the differences can impact treatment of infections caused
by each of them.
A gram positive cell has a weaker cell wall and it has a layer of
peptidoglycan. A gram negative cell has the cell wall between the plasma
and outer membrane.
12
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