Spectrum of Commonly Used Agents

Question 1

Seven examples of beta-lactams

Answer 1

Penicillin G
Amoxicillin/Ampicillin
Co-amoxiclav
Flucloxacillin
Piperacillin
Imipenem/Meropenem
Cephalosporins

Question 2

Penicillin G (against/derivative)

Answer 2

Against: Gram positive, meningococci (-ive), IV pneumococci and strep pyogenes

Derivative: phenoxymethylpenicillin (better local absorption)

Question 3

Amoxicillin/Ampicillin (against/better/affected)

Answer 3

Against: Gram negative, streptococci, enterococci and some coliforms

Better: oral absorption than penicillin G

Affected: by beta-lactamase production

Question 4

Co-amoxiclav (makeup/against)

Answer 4

Makeup: amoxicillin and clavulanic acid

Against: beta-lactamase producing coliforms

Question 5

Flucloxacillin (resistant/represented)

Answer 5

Resistant: to staphylococcal beta-lactamase
Represented: by methicillin in the lab

Question 6

Piperacillin (against/used with)

Answer 6

Against: more Gram negative, pseudomonas, anaerobic infection

Used with: tazobactam (beta-lactamase inhibitor - pip/taz)

Question 7

Imipenem/Meropenem (group/spectrum)

Answer 7

Group: carbapenems
Spectrum: widest, including anaerobes

Question 8

Cephalosporins (generations/encourage/replacement)

Answer 8

Generations: increased gram negative and decreased gram positive activity

Encourage: clostridium difficile infections

Replacement: co-trimoxazole

Question 9

Aminoglycosides (against/resisted/use)

Answer 9

Against: Gram negative including pseudomonas, staphylococci

Resisted: by streptococci

Use: parenteral (possible toxicity - gentamycin)

Question 10

Glycopeptides (against)

Answer 10

Against: aerobic and anaerobic Gram positive

Question 11

Macrolides (against/alternative to/examples)

Answer 11

Against: Gram positive, atypical pneumonia e.g chlamydia psittacci

Alternative to: penicillin

Examples: clarithromycin/erythromycin

Question 12

Quinolones (against/poor/levofloxacin)

Answer 12

Against: all Gram negative including pseudomonas

Poor: streptococci action

Levofloxacin: against pneumococci and other atypical pneumonia

Question 13

Five examples of miscellaneous antibiotics

Answer 13

Metronidazole
Fusidic acid
Trimethoprim
Tetracyclines
Clindamycin

Question 14

Metronidazole (against/used in)

Answer 14

Against: Gram positive and negative anaerobes, no aerobic activity

Used in: treatment of intra-abdominal abscess

Question 15

Fusidic acid (against/used in)

Answer 15

Against: staphylococci

Resisted by: staph. aureus

Used in: osteomyelitis and pneumonia (diffuses well in bone and tissue)

Question 16

Trimethoprim (used in/used with)

Answer 16

Used in: UTI treatment

Used with: sulphamethoxazole as co-trimoxazole for chest infections (less likely to cause clostridium difficile infections than e.g. cephalosporins)

Question 17

Tetracyclines (used in/contraindications)

Answer 17

Used in: genital and respiratory tract infections

Contraindications: not used in children or pregnant women as it is deposited in teeth and bone

Question 18

Clindamycin (group/against/good for/can)

Answer 18

Group: lincosamides

Against: Gram positive and anaerobes

Good for: tissue penetration/oral use

Can: cause pseudomembranous colitis

Question 19

Give two examples of urinary tract agents

Answer 19

Nalidixic acid
Nitrofurantoin

For use in lower UTIs - cystitis

Question 20

Nalidixic acid (against/urinary)

Answer 20

Against: coliforms only
Urinary: antisceptic, fully excreted in urine

Question 21

Nitrofurantoin (against)

Answer 21

Against: most gram negative (except proteus/pseudomonas) and some gram positive (unlike nalidixic acid)

Question 22

Give two examples of newer antimicrobial agents

Answer 22

Linezolid

Fidaxomicin

Question 23

Linezolid (against/use/can)

Answer 23

Against: MRSA

Use: orally, unlike glycopeptides

Can: cause bone marrow suppression

Question 24

Fidaxomicin (against)

Answer 24

Against: clostridium difficile recurrance