PPT 3

Question 1

Amoxicillin

Answer 1

Penicillins kill susceptible bacteria by specifically inhibiting the transpeptidase that catalyses the final step in cell wall biosynthesis, the cross-linking of peptidoglycan

Question 2

Benzylpenicillin

Answer 2

Natural penicillin antibiotic that is administered intravenously or intramuscularly due to poor oral absorption

Question 3

Co-amoxiclav

Answer 3

AKA augmentin

Amoxicillin + clavulanate

Clavulanic acid is a beta-lactamase inhibitor - prevents bacteria from inactivating certain beta lactam antibiotics

Question 4

Flucloxacillin

Answer 4

A penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms

Question 5

Piperacillin-tazobactam

Answer 5

Piperacillin = penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms

Tazobactam = beta-lactamase inhibitor

Used to treat hospital acquired pneumonia

Question 6

Cefotaxime

Answer 6

Third-generation cephalosporin antibiotic

Broad spectrum activity against Gram positive and Gram negative bacteria

Inhibits bacterial cell wall synthesis

Question 7

Cefaclor

Answer 7

2nd generation cephalosporin

Beta lactam antibiotic - prevents bacterial cell wall synthesis

Question 8

Ceftriaxone

Answer 8

Cephalosporin antibiotic

Works by inhibiting the mucopeptide synthesis in the bacterial cell wall - attach to penicillin binding proteins to interrupt cell wall biosynthesis, leading to bacterial cell lysis and death.

Question 9

Azithromycin

Answer 9

Broad-spectrum macrolide antibiotic - 50s inhibitor

Primarily used for the treatment of respiratory, enteric and genitourinary infection

Question 10

Clarithromycin

Answer 10

Semisynthetic macrolide antibiotic derived from erythromycin, inhibits bacterial protein synthesis by binding to the bacterial 50S ribosomal subuni

Question 11

Erythromycin

Answer 11

Belongs to the macrolide group of antibiotics - 50s inhibitor

Stops bacterial protein synthesis by inhibiting the transpeptidation/translocation step of protein synthesis and by inhibiting the assembly of the 50S ribosomal subuni

Question 12

Gentamicin

Answer 12

30s inhibitor

Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter

Question 13

Streptomycin (TB)

Answer 13

30s inhibitor

Given via deep IM for drug resistant TB (in combination with other drugs)

Question 14

Tobramycin

Answer 14

30s inhibitor

Question 15

Doxycycline

Answer 15

Mainly bacteriostatic and are thought to exert antimicrobial effects by the inhibition of protein synthesis

30s inhibitor

Question 16

Tetracycline

Question 17

Minocycline (acne)

Question 18

Lymecycline (acne)

Answer 18

30s inhibitor

Question 19

Moxifloxacin

Answer 19

Synthetic fluoroquinolone antibiotic agent

DNA inhibitor

Inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV. DNA gyrase is an essential enzyme that is involved in the replication, transcription and repair of bacterial DNA

Question 20

Rifampicin

Answer 20

Inhibits DNA-dependent RNA polymerase activity by forming a stable complex with the enzyme. It thus suppresses the initiation of RNA synthesis

Blocks RNA synthesis

1st line for TB

Question 21

Isoniazid

Answer 21

Antibacterial agent used primarily as a tuberculostatic - highly specific agent against mycobacterium, ineffective against other microorganisms

Question 22

Pyrazinamide

Answer 22

Highly specific agent and is active only against Mycobacterium tuberculosis

Question 23

Ethambutol

Answer 23

Ethambutol is an oral chemotherapeutic agent which is specifically effective against actively growing microorganisms of the genus Mycobacterium, including M. tuberculosis. Ethambutol inhibits RNA synthesis and decreases tubercle bacilli replication

Question 24

What does a CURB 65 score of 3 or more mean?

Answer 24

Patient is at high risk of death and should be reviewed by senior at the earliest opportunity

Question 25

If a patient has a CURB 65 score of 4 or 5, what should be done?

Answer 25

Assess the patient with specific consideration to the need for transfer to critical care

Question 26

If a patient has a CURB score of 0 or 1, what does this mean?

Answer 26

Patient is at low risk of death from pneumonia and may be suitable for home treatment

Question 27

Discuss management of a patient with pneumonia, with reference to CURB scores

Answer 27

CURB 65 = 0-1: 1.5% 30 day mortality, low risk patient so consider home treatment CURB 65 = 2: 9.2% 30 day mortality, will most likely need admitting or managing closely as an outpatient CURB 65 = 3-5: 22% 30 day mortality, admit the patient and treat as severe pneumonia

Question 28

Your patient has a CURB score of 0-1, which antibitoic are you going to prescribe?

Answer 28

Oral amoxicillin if able to tolerate penicillin Oral doxyclycline if allergic to penicillin

Question 29

Your patient has a CURB score of 2, which antibiotic are you going to prescribe?

Answer 29

Oral doxycycline OR No penicillin allergy: oral amoxocillin + clarithromycin Penicillin allergy: clarithromycin If IV needed: No penicillin allergy: benzylpenicillin + clarithromycin Penicillin allergy: clarithromycin

Question 30

Your patient has a CURB score of 3 or more, which antibiotic will be prescribed?

Answer 30

Able to tolerate penicillin: IV co-amoxiclav + IV clarithromycin Allergic to penicillin: IV cefotaxime + IV clarithromycin

Question 31

What is antimicrobial stewardship?

Answer 31

'an organisational or healthcare-system-wide approach to promoting and monitoring judicious use of antimicrobials to preserve their future effectiveness'

Question 32

What are the principles of good prescribing when prescribing antibiotics?

Answer 32

1. Prescribe shortest effective course 2. Prescribe most appropriate dose 3. Appropriate route of administration

Question 33

BTS recommendations when prescribing in cases of pneumonia

Answer 33

1. Diagnosis and prescription of antibiotics to be reviewed by senior clinician 2. Indication for antibotics to be written clearly in notes 3. Need for IV antibitoics to be reviewed daily 4. De-escalation of therapy to be considered as soon as appropriate 5. Strongly consider narrowing specturm of antibiotic

Question 34

Principles of antimicrobial prescribing

Answer 34

Right antibiotic - what organism? risk factors for resistance? Effective antibiotic? Right time - have we got culture results? Right dose Right route - can this patient have oral antibiotics? Least harm - most narrow spectrum possible, minimum treatment duration, least amount of side effects

Question 35

Why do we try and avoid using broad spectrum antibiotics in community acquired pneumonia?

Answer 35

To reduce the risk of c.diff colonisation

Question 36

What types of healthcare acquired infections does the use of broad specturm antibiotics predispose to?

Answer 36

C.diff MRSA Extended spectrum beta-lactamases - ezymes that are resistant to most beta-lactam antibiotics \*\*found exclusively in gram negative organisms

Question 37

What is atypical pneumonia?

Answer 37

Refers to the radiological pattern associated with patchy inflammatory changes often confined to the pulmonary interstitium most commonly associated with atypical bacterial aetiologies e.g. - Mycoplasma pneumoniae - Chlyamydia pneumoniae - Legionella pneumoniae

Question 38

Discuss the principle of TB drug therapy

Answer 38

Regimens generally consist of an intense phase (2mo) followed by a continuous phase (4-7mo) Intensive phase usually consist of **rifampicin, isoniazid, pyrazinamide and ethambutol** Continuation phase usually consists of **isoniazid and rifampicin** administered for an additional 4 months

Question 40

Discuss rifamycin drug interactions

Answer 40

Reduced plasma concentrations of oestogen in those taking oral contraceptives Reduces plasma concentration of warfarin, phenytoin (for eplisepsy, blocks sodium channels) and sulphonylureas (T2DM)

Question 41

Isoniazid

Answer 41

Pro-drug, activated by catalase peroxidase activity within the mycobacteria The active product blocks the synthesis of mycolic acids unique to the cell wall of mycobacteria and blocks nucleic acid synthesis Can cause hepatotoxicity and peripheral neuropathy

Question 42

Pyrazinamide

Answer 42

If pyrazinamide us used alone for the treatment of TB resistance develops rapidly Can cause hepatotoxicity and a rise in plasma bilirubin usually warrant cessation of treatment Crosses BBB so good for TB meningitis

Question 43

What are the adverse effects of ethambutol?

Answer 43

- Visual disturbances - Optic neuritis - produces red green colour blindness - Hyperurucaemia and gout - Nephrotoxicity