DR. MABANAG - AMINOGLYCOSIDES, SPECTINOMYCIN & TETRACYCLINE Flashcards
1
Q
BACTERIA RIBOSOMES
A
70 S RIBOSOMES
SUBDIVIDED TO:
50 S
30 S
2
Q
EUKARYOTES RIBOSOMES
A
80 S RIBOSOMES
3
Q
How Ribosomes Work
A
- The tRNA loaded with particular amino acids enters the ribosome at the A site
- The tRNA’s anticodon has to match the codon (group of 3 nucleotides) on the mRNA
- In the P site of the ribosome, a peptide bond forms between the previous amino acid and the new amino acid formed
- The empty tRNA exits the E site
- This process repeats for the whole length of the
mRNA and the polypeptide chain continues to grow
4
Q
INHIBITORS OF 30S RIBOSOMAL SUBUNIT
A
A-S-T
○ Aminoglycosides
○ Spectinomycin
○ Tetracycline
5
Q
INHIBITORS OF 50S RIBOSOMAL SUBUNIT
A
ML-CO
○ Macrolides
○ Lincosamides
○ Chloramphenicol
○ Oxazolidinones
6
Q
Block the initiation of translation and causes the misreading of mRNA
A
AMINOGLYCOSIDES
7
Q
Block the attachment of tRNA to the ribosome
A
TETRACYCLINES
8
Q
Each interferes with a distinct step of protein synthesis
A
STREPTOGRAMINS
9
Q
Prevent continuation of protein synthesis
A
MACROLIDES
10
Q
Prevents peptide bonds from being formed
A
CHLORAMPHENICOL
11
Q
Prevents continuation of protein synthesis
A
LINCOSAMIDES
12
Q
Interfere with the initiation of protein synthesis
A
OXAZOLIDINONES
13
Q
Used most widely in combination with other agents to treat drug-resistant organisms
A
AMINOGLYCOSIDES
14
Q
are better given in combination for added spectrum of activity and synergism
A
AMINOGLYCOSIDES
15
Q
- Used in combination with other TB drugs for treatment of mycobacteria infections such as Tuberculosis
- Outside of the urinary tract, aminoglycosides are not very effective, and it should be added with other drugs.
○ For urinary tract infections, monotherapy is enough
A
AMINOGLYCOSIDES
16
Q
usually used for TB
A
STREPTOMYCIN (AMINOGLYCOSIDES)
17
Q
EYE AND EAR INFECTIONS
A
NEOMYCIN (AMINOGLYCOSIDES)
18
Q
Obsolete. Formerly used as 2nd line drug for TB
A
KANAMYCIN (AMINOGLYCOSIDES)
19
Q
irreversible inhibitors of protein synthesis (30s and 50s subunit of ribosomes) though the precise mechanism of bacterial activity is still unclear
A
AMINOGLYCOSIDES
20
Q
3 WAYS IN INHIBITING PROTEIN SYNTHESIS
A
- Interference with the initiation complex of
peptide formation - Misreading of mRNA
● Causes incorporation of incorrect amino acids into peptide and results in nonfunctional protein - The breakup of polysomes into nonfunctional monosomes
● Occurs simultaneously, the overall effect is irreversible and leads to cell death
21
Q
○ After IV administration, aminoglycoside concentration is highest in the ____ and in the _____
A
1.KIDNEYS
2. EARS
○ why the side effects are in the kidneys and inner ear
AMINOGLYCOSIDES ADVERSE EFFECTS
1.NEPHROTOXIC
2. OTOTOXIC
22
Q
in INFECTIVE ENDOCARDITIS
A
Synergistic killing effect
23
Q
○ Achieve bactericidal activity in the treatment of enterococcal endocarditis
A
Penicillin + aminoglycoside
24
Q
○ Shorten therapy duration for Viridans streptococcal endocarditis
○ The duration for Viridans streptococcal endocarditis is 2 weeks but the usual duration is longer.
A
Penicillin + aminoglycoside
25
AMINOGLYCOSIDES ADVERSE EFFECTS
1.NEPHROTOXIC
2. OTOTOXIC
3. CURARE LIKE EFFECTS - HIGH DOSE (Reversible by Calcium gluconate or Neostigmine)
4. HYPERSENSITIVITY
26
Mainly used as a second-line agent for the treatment of tuberculosis
STREPTOMYCIN
27
ENTEROCOCCAL ENDOCARDITIS
2-week therapy: Viridans enterococcal endocarditis
Penicillin + Streptomycin:
28
for susceptible strains when aminoglycoside is selected as adjunct therapy
GENTAMICIN
29
Inhibits in vitro staphylococci and gram-negative bacteria including Enterobacteriaceae and Pseudomonas aeruginosa
GENTAMICIN
30
High level Aminoglycoside Resistant Enterococci
(HLARE)
STREPTOMYCIN
31
● In cases of drug-resistant meningitis or severe cases of beta-lactam allergy, aminoglycosides are still an alternative.
INTRATHECAL INJECTION OF GENTAMICIN SULFATE
32
slightly more active vs Serratia marcescens
GENTAMICIN
33
slightly more active vs Pseudomonas aeruginosa
TOBRAMYCIN
34
Enterococcus faecalis SUSCEPTIBLE TO:
1. GENTAMICIN
2.TOBRAMYCIN
35
Enterococcus faecum
SUSCEPTIBLE TO:
RESISTANT TO:
SUSCEPTIBLE TO: GENTAMICIN
RESISTANT TO: TOBRAMYCIN
36
● Semi-synthetic derivative of Kanamycin- but less toxic
● Better resistance profile than Gentamicin and Tobramycin
AMIKACIN
37
● Effective against:
○ Proteus spp
○ Pseudomonas
○ Enterobacter
○ Serratia
○ Mycobacterium tuberculosis
● Also a second line treatment for tuberculosis
AMIKACIN
38
● Same characteristics with Gentamicin and Tobramycin
● May be active against some Gentamicin-resistant and Tobramycin-resistant bacteria
NETILMICIN
39
● Active vs G(+) & G(-) bacteria and some mycobacteria
● P. aeruginosa and Streptococci - RESISTANT
Aminoglycosides:Neomycin, Kanamycin, Paromycin
40
limited to topical and oral use due to
parenteral toxicity
○ Occurrence of higher resistance compared
to others
NEOMYCIN
41
treatment for MDR TB (obsolete
already) but alternate agents (Amikacin) may be
preferred
KANAMYCIN
42
more on for helminths
○ effective vs visceral leishmaniasis when given parenterally and intestinal Entamoeba histolytica infection
PAROMOMYCIN
43
HIGHLY TOXIC
1. NEPHROTOXIC
2.OTOTOXIC
Neomycin, Kanamycin, and Paromomycin
44
NEUROMUSCULAR BLOCKADE
1. Inhibition of presynaptic ACh release
2. ↓ motor end-plate sensitivity to ACh
3. Interference with Ca+ action at neuroreceptors
45
● 30S attaching antibiotic
● Active in vitro vs G(+) & G(-) bacteria
● Alternative tx for drug-resistant gonorrhea or
gonorrhea in penicillin-allergic patients in 1960s
SPECTINOMYCIN
46
crystalline amphoteric substances of low solubility
TETRACYCLINE
47
Tetracycline:Classification&Basic Structure
Short Acting
○ Tetracycline
○ Oxytetracycline
Intermediate Acting
○ Demeclocycline
○ Methacycline
Long Acting
○ Doxycycline
○Minocycline
48
*Broad spectrum BACTERIOSTATIC antibiotic that inhibits protein synthesis
*Enters microorganism in part by passive diffusion and in part by energy dependent active transport
TETRACYCLINE MOA
49
Once inside the cell, it binds irreversibly to 30s ribosomal subunit
○ Blocking the binding of aminoacyl-tRNA to the acceptor site on the mRNA-ribosome complex
○ Prevents addition of amino acids to growing peptide
TETRACYCLINE MOA
50
should be taken
on empty stomach
Tetracycline & Demeclocycline
51
absorption not
impaired by food
Doxycycline & Minocycline
52
widely distributed across tissue and
bodily fluids except CSF
TETRACYCLINE
53
Drug of choice for:
○ Rickettsiae
○ Borrelia spp. (Rocky Mountain Spotted
Fever)
○ Lyme disease
○ Anaplasma phagocytophilum
○ Ehrlichia spp.(can affect dogs and humans)
TETRACYCLINE
54
Also an excellent drug for:
○ Mycoplasma pneumonia, Chlamydia,
and; Spirochetes
○ Helicobacter pylori
○ G(+) & G(-) bacterial infections
○ Vibrio infections
TETRACYCLINES
55
alternative agent for primary and secondary syphilis in patients with penicillin allergy
DOXYCYCLINE
56
rarely used antibacterial
○ Used off-label in the treatment of SIADH due of its inhibition of ADH in the renal tubule
DEMECLOCYCLINE
57
● First glycylcycline to be used clinically
● Very broad spectrum - many tetracycline-resistant
strains are susceptible
TIGECYCLINE
58
○ Methicillin-resistant Staphylococcus aureus (MRSA)
○ Vancomycin intermediate Staphylococcus aureus (VISA)
○ Vancomycin-resistant Staphylococcus aureus (VRSA)
TIGECYCLINE
59
○ Streptococci: Penicillin-susceptible and resistant
○ Enterococci: Vancomycin-resistant strains,
○ Gram-positive rods
○ Enterobacteriaceae including Extended
spectrum beta-lactamase (ESBL)
○ Multidrug-resistant Acinetobacter baumanii
TIGECYCLINE
60
ANAEROBES
● Rickettsia, Chlamydia, Legionella, and Rapidly growing mycobacteria
● Proteus, Providencia, P. aeruginosa - intrinsically resistant
TIGECYCLINE
61
Tetracycline: Adverse Effects
1. GI TRACT
2. RENAL (FANCONI-LIKE SYNDROME, NEPHROGENIC DIABETES INSIPIDUS)
3. BONY STRUCTURES AND TEETH
4. HYPERSENSITIVITY
5. FETALHEPATOTOXICITY
6. DIZZINESS & NAUSEA
7. DEC. PROTHROMBIN ACTIVITY
8. PHOTOSENSITIVITY
9. SUPERINFECTIONS
62
○ ___________ precipitate infections such as:
- Overgrowth of Vaginal candida
- Resistant Intestinal Staphylococci
- Pseudomembranous colitis
secondary to Clostridium difficile (treated by Metronidazole and oral Vancomycin)
- Demeclocycline
TETRACYCLINE
63
1. Which of the following is not an adverse effect of Aminoglycosides?
a. Ototoxicity
b. Nephrotoxicity
c. Neuromuscular blockade
d. AOTA
e. NOTA
E. NOTA
ALLARE ADVERSE EFFECTS OF AMINOGLYCOSIDES
64
2. Which of thefollowing is the first glycycycline used clinically?
a. Minocycline
b. Tetracycline
c. Gentamicin
d. Tigecycline
d.tigecycline
65
3. Which of the following does not act on 30s subunit of ribosome
a. Aminoglycoside
b. Tetracycline
c. Spectinomycin
d. Linezolid
D. LINEZOLID
66
4. Aminoglycosides’ mechanism of action involves:
a. Inhibition of DNA synthesis
b. Inhibition of protein synthesis
c. Inhibition of carbohydrate synthesis
d. NOTA
b. Inhibition of protein synthesis
67
5. Which ofthefollowing is not true?
a. Gentamicin is slightly more active vs
Serratia marcescens
b. Tobramycin is slightly more active vs
Pseudomonas aeruginosa
c. Enterococcus faecalis - susceptible to
Tobramycin only
d. Enterococcus faecum - resistant to
Tobramycin
c. Enterococcus faecalis - susceptible to
Tobramycin only
***SUSCEPTIBLE TO BOTH
68
6. Antibacterial activity persists beyond the time during which measurable drug is present or serum concentration is below MIC is called:
a. Post-antibiotic effect
b. Post-aminoglycoside effect
c. Post-streptomycin effect
d. Post-antifungal effect
a. Post-antibiotic effect
69
7. This drug is used off-label in the treatment of SIADH due of its inhibition of ADH in the renal tubule
a. Streptomycin
b. Amikacin
c. Gentamicin
d. Domocycline
d. Domocycline
70
8. This drug is obsolete. It is formerly used as 2nd line drug for TB
a. Kanamicin
b. Streptomycin
c. Amikacin
d. Erythromycin
a. Kanamicin
71
9. The absorption of this/these drugs are impaired by food ingestion?
a. Doxycycline
b. Minocycline
c. Tetracycline
d. Demeclocycline
e. AANDB
f. CandD
f. CandD
IMPAIRED BY FOOD INGESTION
TETRACYCLINEAND DEMECLOCYCLINE
72
10. The absorption of this/these drugs are not impaired by food ingestion?
a. Doxycycline
b. Minocycline
c. Tetracycline
d. Demeclocycline
e. AandB
f. CandD
e. AandB
NOT INPAIRED BY FOOD INGESTION
DOXYCYCLINE & MINOCYCLINE
