Chapter 10- Antimicrobial Drugs Flashcards
(86 cards)
1
Q
Chemotherapy
A
treatment with chemical substances
2
Q
Drug
A
affects physiology
3
Q
Antimicrobial drugs
A
chemotherapeutic agents used to treat infectious diseases
4
Q
Penicillin
A
Used to treat bacterial infections
5
Q
Bactericidal
A
They kill microorganisms directly
6
Q
Bacteriostatic
A
They inhibit the growth of microorganisms
7
Q
Semisynthetic
A
chemically altered antibiotics, partially man-made
8
Q
Synthetic
A
Antibiotics that are manufactured in lab
9
Q
Selective Toxicity
A
- Drug will only affect microorganisms without damaging human
- Mechanism of action will affect cell structure or metabolism but not both
10
Q
5 ways an antimicrobial drug can kill/prevent microorganisms
A
- The inhibition of cell wall synthesis
- The inhibition of protein synthesis
- Disruption of the plasma membrane
- Inhibition of nucleic acid synthesis
- Inhibiting metabolic pathways
11
Q
The inhibition of cell wall synthesis
and why are these not toxic to humans?
A
- Prevents the cross-linkage of NAM in the peptidoglycan layer (affects tetrapeptide bonds)
- Bacertial cell undergoes lysis due to movement of water
Humans don’t have cell walls
12
Q
The inhibition of protein synthesis
A
- Targets the 70S ribosomes (either the 30S or 50S subunit)
- Targets translation
13
Q
Disruption of the plasma membrane
A
- Some antifungal drugs combine with ergosterol to damage the cell membrane
- Effective in fungal infections
- Humans are susceptible, but not bacteria
14
Q
Ergosterol
A
similar in composition to cholesterol which is found in gram negative bacteria
15
Q
Inhibition of nucleic acid synthesis
A
- Blocks DNA replication or RNA transcription
- Affects both eukaryotic/prokaryotic cells
- Can damage the human host cell
16
Q
Inhibiting metabolic pathways:
In order to produce DNA/RNA, bacteria need _____ _____. ____ disrupts DNA/RNA _______, but humans ______________
A
- Bacteria need folic acid
- PABA
- Humans do not use PABA and therefore have minimal toxicity to these medications
17
Q
6th method- _____ ______, which..
A
Attachment antagonists- blocks viral attachment of receptor proteins
18
Q
Which antibiotics are inhibitors of cell wall synthesis
A
Penicillin, Penicillin derivatives, and Cephalosproins
19
Q
All penicillins have a _____ _____ structure containing a _____ _____ _____
A
All pencillins have a common core structure containing a beta-lactam ring
20
Q
So, _____ _____ are..
A
Beta lactams are inhibitors of cell wall synthesis
21
Q
Natural Penicillin exs and mech. of action
A
Penicillin G and Penicillin V
Inhibits cell wall synthesis
22
Q
The original compound of all the penicillins is
A
Penicillin G
23
Q
Natural Penicillin advantages
A
Inexpensive
Usually not toxic
Good against gram +
24
Q
Natural Penicillin disadvantages
A
Narrow spectrum of activity
Susceptible to penicillinase (AKA beta lactamase)
25
Penicillin G is normally _____, and penicillin V can be ____ ____
Penicillin G is normally **injected** because if taken orally, penicillin G is destroyed by stomach acids
Penicillin V is stable in stomach acids and can be **taken orally**
26
Semisynthetic Penicillin- was developed by
by chemically adding a synthetic side chain to the common core structure of the natural penicillin
27
Semisynthetic Penicillin (3 points)
- More readily absorbed
- Less susceptible to deactivation by beta-lactamase
- Broader-spectrum of activity
28
Types of semisynthetic penicillins
- Oxacillin
- Amoxicillin
- Methicillin
29
Oxacillin
Semisynthetic penicillin that's resistant to penicillinase (beta lactamase)
30
Amoxicillin
Semisynthetic penicillin that was developed to have a broader spectrum of activity
Effective against many gram-positive and gram-negative bacterias
Not resistant to penicillinase
31
Example of a hospital acquired disease
*Pseudomonas aeruginosa*
32
Methicillin
Used in description of antibiotic resistance (MRSA)
33
_______ differ from natural penicillins in that they are ____ to penicillinases and are _____ against more ___--_____ bacteria
**Cephalosporins** differ from natural penicillins in that they are **resistant** to penicillinases and are **effective against more gram-negative bacteria**
34
Polypeptide Antibiotics include ____ and _______
Bacitracin and Vancomycin
35
Bacitracin
- Effective against gram +
- Use is for topical applications
36
Bacitracin is still a ____ ____ ____ but is NOT a ____ _____
Bacitracin is still a cell wall inhibitor but is NOT a beta lactam
37
Vancomycin
- Derived from Streptomyces
- Last line of antibiotic defense for Staphylocccos infections that are resistant to other antibiotics
- NOT a beta lactam
38
Antimycobacterial Antibiotic works against _______ which is
Mycobacteria which is an acid-fast bacteria (waxy cell walls)
39
Example of antimycobacterial antibiotic and 2 points
Isoniazid: -inhibitor of cell wall synthesis
- NOT beta lactam
40
All the ones that are cell wall inhibitors but not beta lactams:
Polypeptide Antibiotics- bacitracin and vancomycin
Antimycobacterial Antibiotics- Isoniazid
41
Inhibitors of proteins synthesis: all exs
- Chloramphenicol
- Aminoglycosides
- Tetracyclines
- Macrolides
42
Chloramphenicol
- Blocks polypeptide formation on 50S subunit
- Side effect: bone marrow suppression
43
Aminoglycosides
- Disrupts the 30S subunit shape
- Good against gram-negative
44
Types of Aminoglycosides
Streptomycin
Neomycin
Gentamicin
45
Streptomycin
Treats tuberculosis
Inhibitor of protein synthesis
46
Neomycin
Topical ointment
Inhibitor of protein synthesis
47
Gentamicin
Useful against *Pseudomonas* infections
Inhibitor of protein synthesis
48
Aminoglycoside side effects
- Ototoxic (deafness)
- Nephrotoxic (kidneys)
49
Tetracyclines
- Blocks the trna site
- Broad spectrum
- Use in young is not recommended to avoid toxicity
50
Tetracyclines toxicity can lead to
Teeth discoloration
51
Tetracyclines example
Doxycycline
52
Macrolides
- Attaches to 50S subunit blocking the movement of mRNA
- ex: erythromycin and azithromycin
- Side effect: Heart
53
What is often used as a penicillin substitute for the treatment of streptococcal and staphylococcal infections in children.?
Erythromycin
54
Disruption of the plasma membrane examples
Polymyxin B and Azoles
55
Polymyxin B
Topical uses
Effective against gram negative
56
Azoles
- Disrupting the ergosterol of fungi can result in channel formation in the cell membrane
- Toxicity: Hepatotoxic
57
Types of azoles end with ____
flucona**zole**
ketoconazole
itraconazole
58
Neosporin is made up of
Polymyxin B (damage the bacterial plasma membrane), bacitracin (inhibit the synthesis of bacterial cell wall), and neomycin (inhibit the synthesis of bacterial protein)
59
Inhibitors of nucleic acid syntheisis
Fluroquinolones
Rifampina
Novobiocin
60
Rifampina
Disrupts RNA polymerase function
61
Novobiocin
inhibits DNA gyrase
62
Fluoroquinolones
- Inhibit DNA gyrase
- Ex: Ciprofloxacin, for anthrax infections
Side effects: impacts joints
63
Inhibiting metabolic pathways
Sulfonamides (sulfa) drug
64
Sulfonamides (sulfa) drug
- Disrupts PABA
- Includes trimethoprim and sulfonamides
- Side affect: skin rash
65
When determining which of the above medications to administer several things must be considered.
1. Spectrum of activity
2. Effectiveness
3. Route of administration
4. Saftey/side effects
66
Effectiveness can be determined by a
diffusion susceptibility test
67
Which spectrum of action may allow for secondary or superinfections
Broad
68
The use of antibiotics has not _____ resistance but rather has ______ for it
The use of antibiotics has not **produced** resistance but rather has **selected** for it
69
Multiple resistance
resistance to many drugs simultaneously
70
Cross-resistance
resistance to drugs of similar action
71
Multiple resistance is often referred to as a
superbug
72
Resistance by bacteria is acquired 2 ways:
- New mutations of chromosomal genes
- Acquisition of **R plasmids** via transformation, transduction, and conjugation
73
How to prevent drug resistance
- Use antimicrobials only when necessary
- Patients must complete the medication
- Researchers can continue to work on semisynthetic/synthetic antimicrobials
- Develop new variations of existing drugs
74
Antimicrobials often work best ________ in a multimodal treatment
Antimicrobials often work best **synergistically** in a multimodal treatment
75
Physicians must consider
1. How antimicrobial agent will be distributed
2. Patient abilities
76
Routes of administration
- Topical application (external injections)
- Oral (no needles)
- Intramuscular administration (needle into muscle)
- Intravenous administration (directly into bloodstream)
- Subcutaneous (injected under skin)
77
What is responsible for conjugation?
Fertility gene (F factor)
78
What does F+ mean?
The F factor is located on the F plasmid and they can form the pilus
79
What is the name for the cell that the plasma is embedded in the chromosome?
Hfr
80
What is the difference between fertility in a plasmid vs in the chromosome?
If it's F+,
The recipient who was F- becomes F+ and no other chromosome gets transferred
81
What is the difference between fertility in a plasmid vs in the chromosome?
If it's Hfr,
They stay F-, but other chromosome does transfer
82
The ____ ___ is not part of the lac operon. It just controls it
regulatory gene
83
In the absence of tryptophan, the tryptophan operon is transcribed. T/F
True
84
The general term for a virus that attacks the prokaryote
Bacteriophage
85
A prokaryote that is F+,
can make a pilus
86
T/F
An Hfr prokaryote transfers the entire plasmid to the recipient
False- it only transfers a section of the chromosome
