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Final

NURS 310 Final: finals

19 pages35 viewsFall 2017

Department
Nursing
Course Code
NURS 310
Professor
C
Study Guide
Final

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Chapter 43: Basic Principles of Anti-Infective Pharmacotherapy
What is a pathogen?
Microbes capable of causing human disease.
Includes: viruses, bacteria, fungi, unicellular
organisms, and multicellular animals
What does pathogenicity mean?
Ability of an organism to cause disease.
Depends on:
- Speed of reproduction
- Skill in bypassing or overcoming body
defences
What is virulence?
Quantitative measure of organism's pathogenicity.
- Almost like potency of a microorganism.
High virulence = produces disease in small numbers
Produce devastating effects through 2 characteristics:
1. Invasiveness
2. Toxicity
What does invasiveness mean?
Ability of pathogen to grow extremely rapidly and
cause direct damage to surrounding tissues by their
numbers.
- Some bacteria secrete an enzyme that digests
the matrix btw human cells allowing
penetration to anatomical barriers easier.
What does toxicity mean?
Exotoxins: proteins released by bacteria that have the
ability to inactivate or kill host cells.
Clostridium botulinum: most potent toxins, attaches
to motor neurons and prevent acetylcholine for being
released.
Endotoxins: harmful non-protein chemicals that are
part of the outer layer of normal cell of gram-negative
bacteria. After bacterial cell dies, endotoxins go into
surrounding tissues. This causes macrophages to
release cytokines, causing inflammation, fever and
chills.
How are bacteria described?
1. Staining characteristics
- Examine microscopically
- Gram positive: bacteria that contain thick cell
wall composed of peptidoglycan and retain
violet color after staining
- Gram negative: thin cell walls that lose violet
stain.
2. Shape
- Determined microscopically
- Rod shapes are called bacilli
- Spherical shapes are called cocci
- Spiral shapes are called spirilla
3. Ability to use oxygen
- Aerobic: thrive in O2 rich environment
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- Anaerobic: thrive without O2
Why is it important to identify the type bacteria?
Abx are different for each one.
What are anti-infectives drugs classfied by?
1. Susceptible organisms
2. Chemical structures
3. Mechanism of Action
What do anti-infectives do?
Effectively get rid of pathogen
What does antibiotic mean?
Natural substance produced by microorganism that
kills other microorganisms.
What are the two means of grouping widely used?
Chemical classes: usually are structurally similar and
usually share similar antibacterial properties and
adverse effects.
Pharmacological classes: predict similar actions and
adverse effects
Review page 515 table 43.2.
What are the chemical classes and their mechanism of
action?
MoA: Inhibition of cell wall synthesis
Chemical Classes: Penicillins, Cephalosporins,
Carbapenems, Miscellaneous
MoA: inhibition of protein synthesis
Chemical Classes: Aminoglycosides, Tetracyclines,
Macrolides, Oxazolidinones
MoA: disruption of plasma memberane
Chemical Classes: Azoles, Polyenes
MoA: inhibition of nucleic acid synthesis
Chemical Classes: Fluroquinolones
MoA: inhibition of metabolic pathways
Chemical Classes: Sulfonamides
What are three ways bacterias are eliminated through
drugs?
Bacteriocidal: killing bacteria
Bacteriostatic: slow-growth process
Selective Toxicity: target unique differences btw
human and bacterial, fungal, and protozoan cells.
Explain each mechanism of action for anti-infectives:
1. Inhibition of cell wall synthesis
- Bacteria have a thick cell wall that causes high
osmotic pressure.
- Bacteria also have “peptidoglycan”; strong,
repeating network of carbohydrate and protein
chains
- Different drugs act on the cell wall difference
and use it to destroy the bacteria
2. Inhibition of protein synthesis
- Aminoglycosides change the shape of
ribosomal units necessary for protein synthesis
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for bacteria’s.
3. Disruption of the Plasma Cell Membrane:
- Changes permeability of phospholipids in
bacteria.
4. Inhibition of Nucleic Acid Synthesis:
- Affect DNA gyrase, gyrase is used for cell
replication and uncoils DNA.
5. Inhibition of Metabolic Pathways:
- Due to the fast growth, bacteria requires a lot
of nutrients to replicate. There are drugs that
act as a nutrient but are really inhibiting the
replication process.
What is acquired resistance?
Ability of an organism to become unresponsive over
time to the effects of anti-infectives.
What are the mechanisms of resistance that bacteria
can acquire?
1. Destruction of the drug.
- Enzymes that destroy or deactivates the drug
2. Prevention of drug entry into pathogen.
- Inactivates drug as it crosses cell wall
3. Removal by resistance pumps.
- Pumps antibiotic out before entering
intracellular targets
4. Alteration of drugs target site.
- Bind to receptor changing its shape not
allowing drug to bind
5. Development of alternative metabolic pathway.
- Alternative means of obtaining the essential
nutrients for it to grow.
Explain the concept of promotion of resistance:
If we kill bacteria using antibiotics, the ones that
remain functioning are the ones that are resistant to the
antibiotic. Therefore the resistant bacterias now have
the ability to be able to replicate much faster and pass
on the gene that is now resistant to the conventional
drug therapy.
Bacteria passes its gene through a process called
conjugation
How do bacteria obtain resistance?
mutations
What does antimicrobial resistance mean?
Bacterias that have resistant strains in them
What are nosocomial infections?
Infections acquired in hospital or healthcare setting
which are often resistant to common antibiotics.
What organizations monitors trends in antimicrobial
use and resistance across canada?
CIPARS
What do they do?
Use evidence-based policies to control antimicrobial
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