Pharmacology Antibiotics Flashcards
(55 cards)
1
Q
Opportunistic Pathogens
A
Organisms that do not normally produce disease
- Malnutrition, immunodeficiency, antibiotic treatment
- Staphylococcus aureus, E. coli, candida
2
Q
Circle shaped bacteria
A
(Coccus)
Ex: streptococcus, staphylcoccus
3
Q
Rod shaped bacteria
A
(bacillus)
Ex: escherichia, balicus
4
Q
Spiral shaped bacteria
A
(spirillum)
Ex: leptospira, spirillum
5
Q
Gram-Negative
A
do not retain the gram stain
- thin cell wall surrounded by an outer lipopolysaccharide membrane
- Examples:
- E. coli, gonorrhoeae, pseudomonas, pneumoniae, proteus mirabilis
6
Q
Gram-Positive
A
retain gram stain
- thicker cell wall
- Example:
- bacillus anthracis, Staph, Strep, C. diff
7
Q
Two names for a cell wall
A
peptidoglycan or murein
8
Q
Chemotherapeutic agents
A
antibacterial, antifungal, antiparasitic, antiviral, antineoplastic
9
Q
A
- Inhibition of cell wall synthesis
- penicillins, cephalosporins, bacitracin, and vancomycin
- Inhibition of protein synthesis
- chloramphenicol, erythromycin, tetracyclines, and streptomycin
- Inhibition of Nucleic acid Replication
- Quinolones, Rifampin
- Injury to plasma membrane
- polymyxin B
- Inhibition of synthesis of essential metabolites
- sulfanilamide, trimethoprim
10
Q
Which chemotherapy agents are most and least toxic?
A
least: antibacterials
most: antineoplastics
11
Q
Bacteriostatic
A
agents that inhibit the growth of bacteria
12
Q
bactericidal
A
agents that kill bacteria
13
Q
Pseudomembranous Colitis
A
associated with Clostridium difficile overgrowth
(C. diff)
14
Q
Vaginal yeast infection
A
Candida albicans overgrowth
15
Q
Cell Wall Synthesis Inhibitors
A
- B-lactam
- penicillins
- cephalosporins
- Polypeptides
- vancomycin
- bacitracin
16
Q
B-Lactam Antibiotics
A
covalently and irreversibly inhibit Penicilin Binding Proteins (PBPs)
PBPs are enzymes that catalyze the crosslinking of the peptidoglycan cell wall
- Transpeptidases
- Carboxypeptidases
- Endopeptidases
17
Q
Resistance to B-Lactam Antibiotics
A
- Inactivation by B-lactamase
- modification of penicillin binding proteins
- impaired penetration of drug
- effux of drug
- gram-negative bacteria may synthesize an efflux pump that transports B-lactams
18
Q
B-Lactamase Inhibitors
A
Clavulanic acid, sulbactam, tazobactam
19
Q
Penicillin G
A
- narrow spectrum
- high activity against gram-positive bacteria
20
Q
Ampicillin
A
- extended spectrum
- high activity against gram positive
- greater activity against gram-negative
- Associated with pseduomembranous colitis
21
Q
Unasyn
A
Ampicillin + Sulbactam
22
Q
Nafcillin
A
- high activity against gram-positive
- resistant to B-lactamases
- may cause Neutropenia
23
Q
Hypersensitivity reactions to Penicillins
A
- immediate ( <20 min)
- anaphylactic shock
- accelerated
- uticaria
- late (72hrs - weeks)
- rashes
24
Q
Cephalosporin Spectrum
A
Gram-Positive activity decreases by generation
( 1 > 2 > 3 )
Reversed for gram-negative activity
25
Cephalosporins
* organized into "generations"
* more resistant to B-lactamases
* spectrum of activity
26
1st generation Cephalosporins
Cefazolin
drug of choice for surgical prophylaxis
27
2nd generation Cephalosporin
Cefotetan
greater activity against anaerobic bacteria
28
Vancomycin
* glycopeptide
* inhibits transglycosylase enzyme
* active against gram-positive
* staph
* C. diff
29
Red-Man Syndrome
adverse effect of Vancomycin
* histamine release promotes chills, fevers, and rash
* avoid by slowing rate of infusion
30
Bacitracin
* Cyclic polypeptides isolated from Bacillus
* mixture of bacitracin A, B, and C
* Mechanism of Action
* disrupts peptidoglycan synthesis
* Mechanism of Resistance
* BcrABC transporter
* Active against gram-positive
* usually give topically
31
Inhibitors of DNA Replicaiton and Transcription
Quinolones and Riflampin
32
Quinolone Examples
Ciprofloxacin (Cipro) and Levofloxacin (Levaquin)
33
Quinolone Mechanism of Action
Inhibits topoisomerases II (DNA gyrase) and IV
34
DNA gyrase
relaxes supercoiled DNA required for normal transcription
(inhibitied by Quinolones)
35
Topoisomerase IV
separates replicated chromosomal DNA into daugter cells
(inhibited by Quinolones)
36
Protein Synthesis Inhibitors
* Aminoglycosides
* Gentamicin
* Tetracyclines
* Doxycycline
* Lincosamides
* Clindamycin
Inhibits translation by targeting either 30S or 50S ribosomal subunits
37
Aminoglycosides
Irreversibly inhibits the 30S ribosomal subunit
Example: Gentamicin
* Bactericidal
* Postantibiotic effect
* persists beyond the time during which measurable drug is present
38
Gentamicin
Most active against aerobic gram-negative
Aminoglycosides
39
Tetracyclines
binds reversibly to the 30S ribosomal unit
## Footnote
blocks binding of aminoacyl-tRNA to "A" site
Doxycycline (Adoxa)
* bacteriostatic
* caused bad teeth
40
Lincosamides
binds to 50S ribosomal subunit
* Example: Clindamycin (Cleocin)
* Bacteriostatic or bactericidal depending on concentration
41
Clindamycin
Wide range of aerobic gram-positive and anaerobic gram-negative
(also gram-positive organisms)
42
Anti-Metabolites
Folate, Sulfonamides, Trimethoprim
43
Folate
substrate for bacterial synthesis of purines and nucleic acid
(synthesized from PABA)
44
Sulfonamides
inhbit formation of dihydrofolic acid by competing with PABA
Example: Sulfamethoxazole
45
Trimethoprim
Selective inhibitor of bacterial dihydrofolate reductase (DHFR)
46
Bactrim
Sulfamethoxazole and Trimethoprim
(SMX-TMP)
Often used to treat pneumonia
synergism: combination therapy is synergistic through inhibition of sequential steps in the same pathway
47
Which one is known as the "last resort" drug?
Vancomycin
active agonist for MRSA
48
Which one promotes the red man syndrome?
Vancomycin
49
Cephalosporins are considered as narrow, intermediate, and broad spectrum of antibacterial activity as the generation goes from \_\_\_\_\_\_
low to high
50
Drugs that block tubular secretions such as probenecid may increase the levels of some cephalosporins. Why?
because those drugs are dependent on this mechanism to be excreted in the urine
51
What are the mechanisms of acquired bacterial resistance
* enzyme that degrades antibiotic
* mutation in target
* synthesis or activation of transport proteins
52
Name examples of cephalosporins of the 3rd and 4th generation
3rd: Cefoxtaxime, Ceftriaxone
4th:
53
Vancomycin is usually administered by ____ route as opposed to Bacitracin, which is used \_\_\_\_
IV
topically
54
Ampicilin, Penicilin G, and Nafcilin are all highly active against \_\_\_\_
gram-positive
55
What are the mechanisms to combat acquired bacterial resistance
* inhibitor of drug-degrading enzyme
* multi-drug therapy
* use antibiotics carefully
