L78 – Drugs used in urinary tract infection Flashcards Preview

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Flashcards in L78 – Drugs used in urinary tract infection Deck (63):
1

Name the infection of bladder, urethra, prostate and upper urinary tract?

Bladder= cystits
Urethra = Urethritis
Prostate = Prostatitis
Upper urinary tract = Pyelonephritis

2

Most common causative agent of Catheter-associated UTI?

Candida spp
E. coli

3

Most common pathogens for urethritis?

Chlamydia trachomatis

Neisseria Gonorrhea

4

Klebsiella pneumoniae is 100% resistant to ?

ampicillin

5

Proteus mirabilis is 100% resistant to ?

nitrofurantoin

6

Quantitative cultures may be optional before treatment of what UTI?

typical acute uncomplicated cystitis

7

Culture urine in patients with which UTI?

upper UTI / complicated UTI / treatment failure

8

What testing is done in all recurrent or complicated UTI?

Susceptibility testing

9

What is the guideline for FIRST LINE antibiotic use in acute Uncomplicated UTI in female adults?

nitrofurantoin (7 days, oral)

amoxicillin-clavulanate (7 days, oral)

10

Why is nitrodurantoin used for acute Uncomplicated UTI in female adults?

Low local resistance rate

Less likely to select drug-resistant organisms

11

What is the guideline for SECOND LINE antibiotic use in acute Uncomplicated UTI in female adults?

All oral:

Cefuroxime (cephalosporin)

Fluoroquinolones:
-Levofloxacin
-Ciprofloxacin
-Ofloxacin

12

Bacteria that cause Acute cystitis?

Escherichia coli,

Staphylococcus saprophyticus,

Group B streptococcus

13

What is the guideline for FIRST LINE antibiotic use in uncomplicated UTI in children?

1st-line: cefuroxime / co-trimoxazole

14

Which drugs are not recommended for infants under 3 months old with UTI?

co-trimoxazole, nitrofurantoin, nalidixic acid

15

What precaution is taken when treating children younger than 3 with UTI?

igher chance of recurrent infection

>> consider antibiotics prophylaxis after
curative treatment

16

What is the guideline for Asymptomatic Candiduria UTI due to Candida spp?

Asymptomatic Candiduria:

 Eliminate predisposing factors, e.g. remove bladder catheters

 DO NOT treat with local / systemic antifungal agents unless patient belongs to high-risk group for
dissemination (e.g. Neutropenic patients)

17

What is the guideline for Symptomatic Candiduria UTI due to Candida spp?

For fluconazole-susceptible organisms: oral fluconazole

For fluconazole-resistant species: AmB deoxycholate, Oral flucytosine

18

What is the guideline for Symptomatic ascending Candida pyelonephritis due to Candida spp?

fluconazole-susceptible organisms: oral fluconazole

For fluconazole-resistant:
AmB deoxycholate, oral flucytosine

19

What do Azoles inhibit?

inhibit synthesis of
ergosterol from lanosterol >> inhibit formation of cell membrane

20

What do Polyenes (e.g. amphotericin B) inhibit?

bind
to ergosterol = cannot form
membrane (impaired integrity)

21

What does Flucytosine inhibit?

inhibits DNA/RNA synthesis

22

Treatment of Candida UTI associated with Fungus Ball?

 Adults: surgical intervention
 Cystitis / pyelonephritis: anifungal treatment

23

What are the 2 Chlamydial infections?

urethritis, cervicitis

24

What is the empirical treatment for Chlamydial infections?

 Azithromycin (oral daily)
or
 Doxycycline (orally twice daily for 7 days)

25

What is the empirical treatment for Chlamydial infections if the patient is pregnant??

use azithromycin instead of Doxycycline

26

WHat are alternative drugs for Chlamydial infections?

tetracycline / erythromycin / ofloxacin

27

WHat are adverse drug reactions from Chlamydial infection drugs?

mostly gastrointestinal (mild to moderate)

28

What is Gonococcal infections?

urethritis (purulent discharge), cervicitis

29

What bacteria causes Gonocaccal infections?

Neisseria
gonorrhoeae

Could be penicillin- and tetracycline-resistant strains

30

What is the empirical therapy for penicillin- and tetracycline-resistant strains of Neisseria gonorrhoeae?

dual therapy:
1) Single IM injection of ceftriaxone
or
cefixime orally

2) Single oral dose of azithromycin

31

Which drugs are no longer the first line for gonococcal infections and why?

Increased resistance to oral cephalosporins / fluoroquinolones = no longer 1st-line

32

Always treat for what infection when treating gonococcal infection?

Always treat also for Chlamydia when treating for gonorrheae (usually infected by both)

33

What is caused by unsuccessful treatment of gonococcal infections?

Unsuccessful treatment can cause pelvic inflammatory disease

34

What is the preferred drug for treating prostatitis? Why?

quinolones (e.g. ciprofloxacin, levofloxacin)

favourable pharmacokinetic
properties:
- high tissue penetration,
mainly excreted into urine

35

Alternative drugs to quinolones for treating prostatitis?

clarithromycin, azithromycin, doxycycline

36

What additional therapeutic effects arise from drugs treating prostatitis?

anti-inflammatory and/or anti-neuropathic effect

37

How do Non-beta-lactams inhibit cell wall synthesis? (e.g. Vancomycin, Bacitracin?

inhibit early steps of
peptidoglycan synthesis (not cross-linkage)

38

Extended spectrum penicillins are effective against which bacteria? Sensitive to what?

Effective vs. many Gram
–ve bacilli in UTI, bacteremia, skin infections.. etc

Sensitive to Beta-lactamase, acid labile

39

What is the drug combo used to counter act B-lactamase produced by bacteria?

ß-lactam (broad
spectrum penicillin)
+
ß-lactamase inhibitors (prevent hydrolysis of β-lactam ring, irreversible)

40

What are the 4 preparations of B-lactam + B-lactamase inhibitors?

 Augmentin® (amoxicillin +
clavulanic acid

 Unasyn® (ampicillin +
sulbactam

 Timentin® (ticarcillin +
clavulanic acid)

 Tazocin® (piperacillin +
tazobactam)

41

Apart from Beta-lactamase, name another mechanism of resistance against Beta-lactams?

Change in structure of transpeptidase to bind less effectively to B-lactam antibiotics

42

MoA of Macrolides and Tetracyclines?

Inhibit 30S:
 Tetracyclines: blocks tRNA binding to ribosome (30S)

Inhibit 50S:
 Macrolides: bind to P site >> inhibit polypeptide chain to be translocated from A to P site

43

What does Aminoglycosides interfere with in bacteria?

binds to 30S ribosome >> disrupt protein synthesis

44

Apart from macrolides, name some other 50s inhibitors?

 Clindamycin
 Linezolid
 Chloramphenicol:

45

Name 2 antibiotics that inhibit folate synthesis in bacteria?

Sulfonamides,
trimethoprim

Both structurally similar to folate intermediates of DNA synthesis

46

MoA of sulfamethoxazole?

structural analog of para-aminobenzoic acid (PABA)):

competitively inhibits
synthesis of dihydrofolic acid from PABA

47

MoA of Trimethoprim?

structural analog of a potion of dihydrofolic acid):

competitively inhibits synthesis of
tetrahydrofolic acid (precursor of DNA, RNA and proteins)

48

Are folate inhibitors bacteriostatic or cidal?

Bacteriostatic

49

What is the synergistic ratio for inhibiton of folate synthesis? Why?

Cotrimoxazole: Trimethoprim/ Sulmethoxazole ratio

1:5

>> sequential blockade in folic acid synthesis

50

Adverse effects of folate synthesis inhibitors?

Skin rash, Megaloblastic anaermia, Haemolytic anaemia (in patients with G6PD deficiency)

51

Name antibiotics that inhibit DNA and RNA synthesis?

RNA = Rifampin/ Riframpicin

DNA = Metronidazole, Quinolones

52

Metronidazole MoA?

Metabolized to unstable molecule with DNA

>> DNA breaks > inhibit DNA synthesis

53

MoA of quinolones?

bind to gyrase- / topoisomerase IV-DNA complex

>> inhibit DNA unwinding during replication >> block DNA synthesis

54

Name some 1st and 2nd gen quinolones?

1st = nalidixic acid

2nd = ciprofloxacin, ofloxacin

55

Name some 3rd and 4th gen quinolones?

3 = Levofloxacin

4 = Gemifloxacin

56

When is Nitrofurantoin taken and not taken?

Taken: For uncomplicated UTI, prophylaxis for recurrent UTI

Not taken: for pyelonephritis due to low tissue penetration

57

Resistance, serum and urine levels of Nitrofurantoin?

Low rate of resistance (due to many mechanisms of action)

Serum level low
Concentrated in urine

58

Harmless side effect of Nitrofurantoin?

Brown urine, but harmless

59

MoA of Nitrofurantoin?

Nitrofuran reductase activates nitrofurantoin

produce reactive intermediates (free radicals) to attack:
- DNA,
-ribosomal proteins,
-respiration,
-macromolecules

60

What is Fosfomycin? MoA?

Phosphenolpyruvate analogue

>> irreversibly inhibits enolpyruvate transferase (MurA) to prevent formation of NAM for cell wall

61

WHat is the gold standard for bacteria?

antibiotic susceptibility testing:

agar diffusion test >> zone of inhibition

62

What is the new method of identifying bacteria?

barcoding approach:

sequence bacterial DNA >> identify a few fingerprint region of bacteria >> compare with database to assess susceptibility

63

How is drug dose determined whilst considering genetics and adverse reaction?

Screen biomarkers / genome to assess adverse reaction

>> determine dose

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