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E Learning General Flashcards

1
Q

d: bactericidal antibiotic

A

kill bacteria

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2
Q

d: bacteriostatic antibiotic

A

inhibit bacterial growth

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3
Q

describe the pathway of an antibiotic that’s taken orally

A

absorbed by small intestine and spread throughout body, some is excreted unchanged in faeces

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4
Q

Name the 3 ways antibiotics work

A

act on bacteria cell wall
affect the bacterial ribosome
acting on bacterial DNA directly

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5
Q

why is the cell wall method used?

A

mammalian cells have no cell wall

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6
Q

why can AB affecting the bacterial ribosome used?

A

mammalian RIBOSOMES are structurally different to bacterial RIBOSOMES

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7
Q

why can AB acting on bacterial DNA directly be used?

A

bacterial DNA structurally diff from mammalian DNA

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8
Q

Name 3 antibiotics that act on the cell wall and are bactericidal

A

Penicillins
Cephalosporins
Glycopeptides

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9
Q

How does penicillin and cephalosporin’s work?

A

inhibit cell wall synthesis by blocking crosslinking peptidoglycan’s

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10
Q

are penicillin’s safe during pregnancy?

A

yes

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11
Q

what are penicillin’s excreted by?

A

kidneys

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12
Q

what is the spectrum of penicillin?

A

broad

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13
Q

what are cephalosporins excreted by?

A

kidneys and urine

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14
Q

name 2 glycopeptides

A

Vancomycin

Teicoplanin (IV)

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15
Q

How do glycopeptide AB work?

A

Vancomycin binds to the end of the growing pentapeptide chain during peptidoglycan synthesis, preventing cross-linking and weakening the bacterial cell wall

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16
Q

how do glycopeptides have to be administered?

A

via IV

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17
Q

How are glycopeptides excreted?

A

via kidneys and urine

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18
Q

what can happen if toxic levels of vancomycin in the blood build up?

A

if the patient already has kidney failure it can cause further kidney damage

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19
Q

what are glycopeptides only active against?

A

organisms with a gram positive cell wall

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20
Q

why may vancomycin be given orally?

A

to treat C.diff infection

where it acts topically on the gut lumen

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21
Q

how do AB that inhibit protein synthesis do so?

A

attach to bacterial ribosomes

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22
Q

are protein synthesis AB bacteriostatic or bactericidal? what is the one exception?

A

bacteriostatic

aminoglycosides

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23
Q

Name the 2 main groups of AB that inhibit protein synthesis

A

Macrolides

Aminoglycosides

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24
Q

Name 3 macrolides

A

Erythromycin
Clarythromycin
Azithromycin

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25
what are macrolides excreted by?
liver biliary tract into the gut ( not excreted in urine)
26
What properties of macrolides make them useful for infections where bacteria hide from hosts immune system?
lipophilic | pass through cell membranes easily
27
name 3 useful ways macrolides can be used and egs
for treating infections caused by intracellular organisms eg legionella for treating infections cause by organisms that don't have a proper bacterial cell wall eg mycoplasma and chlamydia useful as alternate antibiotic for treating some infections where patients are allergic to penicillin
28
Name an aminoglycoside
gentamicin (IV)
29
how does gentamicin work?
binds to ribosomes inhibiting protein synthesis
30
is gentamicin bactericidal or bacteriostatic?
bactericidal
31
what type of bacteria does gentamicin mainly act against?
gram negative aerobic organisms
32
how is gentamicin mainly used?
treating life threatening gram negative infections
33
how is gentamicin excreted?
in the urine
34
why must blood levels of a patient treated with an aminoglycoside be checked regularly?
narrow margin between giving enough antibiotic to treat the infection and overdosing the patient (narrow therapeutic index) could cause damage to kidneys and 8th Cranial nerve
35
what does damage to 8th cranial nerve cause?
deafness and disturbance of balance
36
Name 3 other AB that inhibit protein synthesis
Clindamycin Chloramphenicol Tetracyclines
37
how are all other AB that inhibit protein synthesis excreted?
via liver and biliary system
38
Name the protein inhibiting AB that is used to treat staph and strept in penicillin allergic patients
Clindamycin
39
Name the AB that is commonly used to treat eye infections
Chloramphenicol
40
How do tetracyclines work?
inhibit bacterial protein synthesis by attaching to ribosomes
41
Are tetracyclines bactericidal or bacteriostatic?
bacteriostatic
42
what is the oral tetracycline used in Tayside?
doxycycline
43
what is doxycycline useful for?
treating infections for bacteria with no cell wall eg pneumonia organisms treating some infections for patients who are penicillin allergic
44
Name 3 AB that act on bacterial DNA
Metronidazole Trimethoprim Fluoroquinolones
45
How does metronidazole act, used for and administered?
acts by causing strand breakage of bacterial DNA for infections caused by true anaerobes and protozoa administered orally or IV
46
how does trimethoprim act?
inhibits bacterial folic acid synthesis
47
How is trimethoprim administered, excreted and what is it active against?
given orally (on its own) or in combination with sulphamethoxazole ( orally or IV) excreted in urine active against some gram +ve and -ve bacteria
48
how do fluoroquinolones work?
via interaction with topoisomerases, enzymes responsible for the supercoiling and uncoiling of bacterial DNA, means bacteria can no longer replicate
49
Are fluoroquinolones bactericidal or bacteriostatic?
bactericidal
50
Name the only antibiotics that can be given orally to treat pseudomonas infection
fluoroquinolones
51
fluoroquinolones are excreted by what?
urine
52
Name a fluoroquinolone that is used for a complicated urinary tract infection?
ciprofloxacin
53
Name a fluoroquinolone that is used for severe community acquired pneumonia in penicillin allergic patients
levofloxacin
54
Give some general side effects of antibiotics
nausea diarrhoea - may cause failure in oral contraception resistance
55
how do AB cause severe diarrhoea in elderly patients?
AB kill off normal gut bacterial flora and allow the overgrowth in the bowel of toxin-producing strains of C. difficile
56
side effects of aminoglycosides
gentamicin damages kidneys | causes deafness and dizziness
57
side effects glycopeptides
vancomycin damages kidneys | red man syndrome
58
side effects of tetracyclines
permanent teeth and bone stains in children <12yrs
59
side effects of metronidazole
interacts with alcohol
60
quinolones side effects
weakens tendons joint damage in children may cause seizures
61
give symptoms of penicillin hypersensitivity
itchy rash difficulty breathing, swelling of mouth/ tongue and larynx low blood pressure swelling at injection sight
62
what AB are safe in pregnancy?
penicillins + cephalosporins trimethoprim and metronidazole avoided in first 3 months
63
what cant be used during pregnancy?
gentamicin tetracyclines fluororquinolones
64
what is the ability to become resistant to AB a result of?
a change in bacterial DNA
65
Name the 2 mechanisms bacterial resistance can develop by
genetic mutation | transfer of DNA THAT CODES FOR ANTIBIOTIC RESISTANCE FROM ONE BACTERIUM TO ANOTHER
66
how does the transfer of DNA that codes for antibiotic resistance from one bacterium to another occur?
Transformation Conjugation Transduction
67
how do bacteria reproduce? therefore how does genetic mutation occur?
via binary fission | as there is a lot of scope for misreading of the genetic code
68
d: transformation
when bacteria die and cells break apart, free floating DNA released into thje surrounding environment and my be scavenged by other bacteria and incorporated into their DNA. this DNA may contain genes that code for antibiotic resistance and benefit the recipient cell.
69
d: conjugation
bacteria contain plasmids many plasmids carry genes that transfer resistance to antibiotics a pilus forms between two bacteria when their close together ( hollow bridge like structure) the plasmid replicates and one copy is transferred via the pilus to the other bacterium this enables a previously susceptible bacterium to acquire the antibiotic resistance
70
d: transduction
bacterial DNA is transferred from one bacterium to another inside a virus that infects bacteria -called bacteriophages or phages when a phage infects a bacterium it takes over the bacteria's genetic processes to produce more phages during this process bacterial Dna , which may code for AB resistance may accidently be incorporated into the new phage DNA when the host cell dies and the phages are released , they will contain DNA from the host bacterium and it will be transferred
71
Name the 3 mechanisms of AB resistance
Altered AB target binding site destruction or inactivation of the antibiotic increased efflux
72
how does altered binding site resistance occur?
ome antibiotics work by binding to a ribosome and impair protein synthesis. For resistance, the bug then methylates the ribosome so the antibiotic cannot bind to it and protein synthesis is preserved. B-lactams require a penicillin binding protein to be effective. So the bug produces and altered penicillin binding protein rendering B-lactams useless.
73
how does increased efflux work?
As antibiotic travels through a porin or in by diffusion, the organism has the ability to turn on efflux pumps to pump the antibiotic out and away from its destination.
74
how does destruction of AB work?
The organism has developed an enzyme that hydrolyzes or breaks apart the particular B-lactam, rendering it ineffective. Give a short explanation for how the altering of a binding site with a ribosome causes resistance.

Antibiotics (2 decks)

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