Antibiotics

Question 1

Which type of bacteria have a thick cell wall?

Answer 1

Gram positive

Question 2

What separates the outer membrane from the cell wall of gram negative bacteria?

Answer 2

Periplasm

Question 3

How do bactericidal agents achieve sterilisation?

Answer 3

By directly killing bacteria

Question 4

How do bacteriostatic act?

Answer 4

Suppress growth but do not directly sterilise the infected site

Question 5

What is the issue with the lysis of bacteria by bactericidal agents?

Answer 5

This can lead to the release of toxins and inflammatory material

Question 6

What is meant by the ‘spectrum’ of an antibiotic?

Answer 6

This refers to the range of bacterial species which are effectively treated by the antibiotic

Question 7

All antibiotics within an antibiotic class will have a similar spectrum. T/F?

Answer 7

False

Question 8

What is the difference between broad and narrow spectrum antibiotics?

Answer 8

Broad spectrum antibiotics are active against a wide range of bacteria
Narrow spectrum antibiotics are active against a limited range of bacteria

Question 9

Describe the guided therapy strategy for the use of antibiotics?

Answer 9

This depends on identifying the cause of infection, an agent is then selected for use based on sensitivity testing

Question 10

What spectrum of antibiotics are used for guided therapy?

Answer 10

Narrow spectrum

Question 11

In guided therapy there is as little impact on colonisation and resistance as possible. What is the pay off for this?

Answer 11

The antibiotic often has limited action on the bacteria causing the infection

Question 12

In empirical therapy there is extensive action against the bacteria which might be causing the infection. What is the pay off for this?

Answer 12

There is a large impact on colonisation and resistance

Question 13

What spectrum of antibiotics are used for empirical therapy?

Answer 13

Broad spectrum

Question 14

Describe the empirical therapy strategy for the use of antibiotics?

Answer 14

Used when the initiation of therapy cannot wait for culture results. A best guess therapy is used based on clinical and epidemiological acumen.

Question 15

What is prophylactic therapy?

Answer 15

Used to prevent infection before it begins

Question 16

What is the result of overgrowth of yeasts which can occur with the use of antibiotics?

Answer 16

Thrush

Question 17

What is the result of overgrowth of the bowel which can occur with the use of antibiotics?

Answer 17

Diarrhoea

Question 18

Which antibiotics are particularly associated with the development of c.difficile?

Answer 18

Clindamycin
Co-amoxiclav
Cephalosporins
Ciprofloxacin

Question 19

C.difficile forms spores which can be difficult to eradicate from hospitals. T/F?

Answer 19

True

Question 20

C.difficile can be difficult to treat as it has developed resistance to common antibiotic classes. T/F?

Answer 20

True

Question 21

How is an uncomplicated UTI defined?

Answer 21

A common condition where there are lower urinary tract symptoms without sepsis of evidence of upper tract involvement

Question 22

In uncomplicated UTI, you need to use an antibiotic with systemic activity. T/F?

Answer 22

False - the antibiotic only needs to sterilise the urine so there is no need for systemic activity

Question 23

What is the first line agent used to treat uncomplicated UTI?

Answer 23

Trimethoprim

Question 24

Why is trimethoprim a good choice of antibiotic for uncomplicated UTI in men?

Answer 24

It penetrates well into the prostate

Question 25

Nitrofuratoin is an excellent broad spectrum antibiotic which is concentrated in the urine so has no effect on other tissues. In what cases should it not be used?

Answer 25

In renal failure nitrofurantoin will fail to concentrate in the urine so should not be used in this case

Question 26

Nitrofuratoin is relatively non-toxic in short courses. What can be caused with long term use?

Answer 26

Pulmonary fibrosis

Question 27

What bacteria commonly cause uncomplicated UTIs?

Answer 27

``` E.coli Other coliforms Pseudeomonas Staphylococcus Enterococcus ```

Question 28

If there is a complicated UTI what is the best choice of antibiotic?

Answer 28

Ciprofloxacin

Question 29

If a patient is severely unwell with a UTI then what antibiotics should be used?

Answer 29

Amoxicillin | Gentamicin

Question 30

Beta lactase are safe for use in pregnancy. However, what is the risk of the use of broad spectrum beta-lactam agents in pregnancy?

Answer 30

These are associated with necrotising enterocolitis in premature infants

Question 31

Why should tetracyclines should not be used in pregnancy?

Answer 31

These can cause bone and tooth abnormalities

Question 32

Why should trimethoprim not be used in pregnancy?

Answer 32

Can cause neural tube defects in the first trimester

Question 33

Why should nitrofurantoin not be used in pregnancy?

Answer 33

Can cause haemolytic anaemia in the third trimester of pregnancy

Question 34

Why should aminoglycosides not be used in pregnancy?

Answer 34

Can cause ototoxicity in the second and third trimesters

Question 35

Why should quinolones not be used in pregnancy?

Answer 35

Can cause bone and joint abnormalities

Question 36

What are the four subclassifications of beta lactase antibiotics?

Answer 36

Penicillins Cephalosporins Carbapenems monobactans

Question 37

What is the brand name for the combination of amoxicillin and clavulanic acid?

Answer 37

Augmentin

Question 38

What is the brand name for the combination of piperacillin and tazobactam

Answer 38

Tazocin

Question 39

What is the mechanism of action of beta lactam antibiotics?

Answer 39

Inhibit the cross linking of cell wall peptidoglycan to cause lysis of the bacteria

Question 40

Beta lactams are bacteriostatic antibiotics. T/F?

Answer 40

False - these are bactericidal

Question 41

What kind of organisms typically secrete beta lactamases?

Answer 41

Gram negative organisms | S.aureus

Question 42

Total antibiotic failure is likely with beta lactamases. T/F?

Answer 42

True

Question 43

By which route are beta lactams usually given?

Answer 43

IV

Question 44

When beta lactam antibiotics are given orally, what usually limits the dose?

Answer 44

Vomiting

Question 45

What are the possible adverse effects of beta lactams?

Answer 45

``` Nausea and vomiting Diarrhoea Cholestasis Type 1 hypersensitivity Type 4 hypersensitivity Interstitial nephritis Candidiasis (oral or vulvovaginal) C.difficile infection Selection of resistance bacteria Seizure Haemolysis Leukopaenia ```

Question 46

What is the most common presentation of type one hypersensitivity in patients on beta lactams?

Answer 46

Urticarial rash

Question 47

Patients who are allergic to a penicillin will usually be allergic to other penicillins. T/F?

Answer 47

True

Question 48

What organisms is Benzylpenicillin effective against?

Answer 48

Streptococcus Clostridium Neisseria

Question 49

What organisms is amoxicillin effective against?

Answer 49

``` Streptococcus Enterococcus Neisseria Haemophilus Clostridium ```

Question 50

What organisms is flucloxacillin effective against?

Answer 50

Streptococcus | Staphylococcus (not MRSA)

Question 51

How is Benzylpenicillin administered?

Answer 51

IV

Question 52

Flucloxacillin can be given orally. T/F?

Answer 52

True

Question 53

What organisms are cephalosporins effective against?

Answer 53

``` Streptococcus Staphylococcus (not MRSA) E.coli Neisseria Haemophilus Bacterioles Clostridium Other coliform ```

Question 54

How does the spectrum of cephalosporins change with each generation?

Answer 54

With each generation of cephalosporins the gram negative spectrum increases with some loss of gram positive activity

Question 55

Give an example of a cephalosporin antibiotic?

Answer 55

Ceftriaxone

Question 56

What organisms are carbapenems active against?

Answer 56

Ultra-broad spectrum antibiotics active against most bacteria expect MRSA

Question 57

Carbapenems are resistant to beta lactamases. T/F?

Answer 57

True

Question 58

Give an example of carbapenem.

Answer 58

Meropenem

Question 59

What is the only monobactam currently in use?

Answer 59

Aztreonam

Question 60

Aztreonams can be given to those with a penicillin allergy. T/F?

Answer 60

True

Question 61

How is aztreonam administered?

Answer 61

IV

Question 62

What class of bacteria is vancomycin active against?

Answer 62

Gram positive organisms

Question 63

How is vancomycin administered?

Answer 63

IV

Question 64

Why is vancomycin effective against resistant organisms such as MRSA?

Answer 64

It is not dependent on penicillin binding proteins

Question 65

A loading dose of vancomycin is usually given. T/F?

Answer 65

True

Question 66

Drug monitoring is required for vancomycin. T/F?

Answer 66

True - it has a narrow TI

Question 67

What are the possible toxicities of vancomycin?

Answer 67

Nephrotoxicity | Ototoxicity

Question 68

What happens when vancomycin is injected too rapidly?

Answer 68

red man syndrome - anaphylactoid reaction

Question 69

What classes of protein synthesis inhibitors target the 50S ribosomes?

Answer 69

Macrolides Clindamycin Chloramphenicol

Question 70

What classes of protein synthesis inhibitors target the 30S ribosomes?

Answer 70

Aminoglycosides | Tetracyclines

Question 71

What 'atypical' organisms is clarithromycin effective against?

Answer 71

``` Legionella Mycoplasma Coxiella Chlamydia Chlamydophila ```

Question 72

What is the spectrum of action of calrithromycin?

Answer 72

Active against gram positive and respiratory gram negative bacteria as well as 'atypical' bacteria

Question 73

Macrolides can be given orally even in severe infection T/F?

Answer 73

True

Question 74

Give examples of macrolides?

Answer 74

Erythromycin Clarithromycin Azithromycin

Question 75

What are the possible adverse effects of macrolides?

Answer 75

``` Diarrhoea and vomiting QT prolongation Hearing loss (in long term use) ```

Question 76

Give examples of drugs which macrolides interact with?

Answer 76

Statins | Warfarin

Question 77

Resistance to macrolides is common among 'atypical' pathogens' but uncommon among 'typical' pathogens. T/F?

Answer 77

False - the opposite is true

Question 78

Clindamycin is given IV. T/F?

Answer 78

False - its has excellent oral absorption

Question 79

What organisms is clindamycin effective against?

Answer 79

Bacterioles Clostridium Staphylococcus Streptococcus

Question 80

Why is clindamycin notorious for causing c.difficile?

Answer 80

Its effective on anaerobes means that is is particularly effective at disrupting colonic flora

Question 81

Clindamycin is highly effective at stopping exotoxin production. As such, what conditions is it used to treat?

Answer 81

Toxic shock syndrome Necrotising fascitis Other gram positive toxin mediated disease

Question 82

What are the possible toxic effects of chloramphenicol?

Answer 82

Bone marrow suppression Aplastic anemia Optic neuritis

Question 83

In what situations is chloramphenicol used?

Answer 83

Topical therapy to the eye | Bacterial meningitis with beta lactam allergy

Question 84

What are the possible toxic effects of amnioglycosides?

Answer 84

Hearing loss, loss of balance and oscillopsia Neuromuscular blockade in patients with myasthenia gravis Nephrotoxicity

Question 85

For how long is it appropriate to give a course of gentamicin?

Answer 85

3 days

Question 86

Describe the rationale behind the dosing regimen for gentamicin?

Answer 86

A high initial dose is given to take advantage of the rapid killing seen at high doses A long dosing interval of 24-48 hours is left in order to minimise toxicity In this time there is a prolonged post-antibiotic bacteriostatic effect

Question 87

What organisms are tetracyclines effective against?

Answer 87

``` Streptococcus Staphylococcus Neisseria Haemophilus Enterococcus Mycoplasma Coxiella Chlamydia Chlamydophila Rickettsia ```

Question 88

Give examples of quinolones

Answer 88

Ciprofloxacin | Levofloxacin

Question 89

Quinolones are always given by IV. T/F?

Answer 89

False - oral dosing can be used even in severe infection

Question 90

What organisms is levofloxacin affective against?

Answer 90

Streptococcus Staphylococcus Also some activity against gram negative

Question 91

What organisms is ciprofloxacin affective against?

Answer 91

Gram negative bacteria | Some action against streptococcus and staphylococcus

Question 92

What type of infections is ciprofloxacin used to treat?

Answer 92

UTI | Abdominal infections

Question 93

What type of infections is levofloxacin used to treat?

Answer 93

Respiratory tract infections

Question 94

What are the possible toxicities associated with quinolones?

Answer 94

GI toxicity QT prolongation Tendonitis C.difficile infection

Question 95

In what situations is rifampicin used?

Answer 95

Tuberculosis | Serious gram positive (especially S.aureus) infection

Question 96

Why are drug interactions very important to consider when prescribing rifampicin?

Answer 96

Rifampicin is a potent CYP450 enzyme inducer

Question 97

What four antibiotics are used in standard short course therapy against TB?

Answer 97

Isoniazid Rifampicin Pyrazamide Ethambutol

Question 98

What is the mechanism of action fo quinolones and rifampicin?

Answer 98

DNA and RNA biosynthesis inhibitors

Question 99

Trimethoprim causes an elevation inc creatine which doe not reflect a fall in GFR. T/F?

Answer 99

True

Question 100

What are some of the problems associated with the use of trimethoprim?

Answer 100

Causes an elevation in serum potassium (problematic in patients with chronic renal impairment) Rash GO disturbance

Question 101

Co-trimoxazole (a combination of trimethoprim and sulphamethoxazole) is commonly used. T/F?

Answer 101

False. - it is only used in specialist care due to its significant additional toxicity

Question 102

What type of bacteria is emtronidazole effective against?

Answer 102

Most anaerobic bacteria

Question 103

What type of infection is metronidazole used to treat?

Answer 103

Intra-adominal infections

Question 104

Metronidazole causes an unpleasant reaction with alcohol. T/F?

Answer 104

True

Question 105

Why folate synthesis inhibitor can cause peripheral neuropathy?

Answer 105

Metronidazole

Question 106

Which antibiotic is used to treat mild c.difficile infection?

Answer 106

Oral metronidazole

Question 107

Which antibiotic is used to treat severe c.difficile infection?

Answer 107

Oral vancomycin

Question 108

What is sepsis six?

Answer 108

A range of medical therapies used in the investigation/treatment of possible sepsis. This includes: Titrate oxygen to sats >94% Administer IV empiric antibiotics Start IV fluid resuscitation Take blood cultures to investigate source of infection Measure serial serum lactases Urine output measurement

Question 109

Lactate dehydrogenase is used as a generally marker of injury to cells. T/F?

Answer 109

True

Question 110

What is the benefit of lactase blood tests?

Answer 110

Helps to assess levels of hypoxia and lactic acidosis