1. Which of the following statements regarding penicillins is FALSE? a. They inhibit cell wall synthesis by blocking transpeptidation of peptidoglycan - true b. Penicillin G has no activity against Gram-negative organisms <= active against G+ves, G-ve cocci, and non-b-lactamase anaerobes. Not effective against G-ve baccili c. Penicillin sensitization occurs as a result of exposure to antigens produced by the degradation of penicillin d. Approximately 90% of renal elimination takes place through tubular secretion – and only 10% by filtration e. Oral administration of penicillin should precede or follow food by at least 1 hour
– poorly absorbed with food
2. With regard to antibiotics a. Tetracyclines inhibit transpeptidation by inhibiting peptidyl transferase activity – 30S binding, bacteriostatic b. Aminoglycosides bind to the 50S ribosomal subunit and inhibit translocation
– 30S c. Sulphonamides inhibit cell wall synthesis
– folic acid synthesis thus bacterial DNA synthesis d. Quinolones inhibit DNA gyrase and lead to unwinding of DNA supercoils <= e. Penicillin causes incorrect reading of MRNA at 30S subunit – block transpeptidation and cell wall synthesis
3. The mechanism of action of beta-lactam antibiotic is a. To inhibit hydroxylation in bacterial cell wall synthesis b. To inhibit transpeptidation in peptidoglycan synthesis <= c. To add alanine to the peptidoglycan chain d. To promote transpeptidation in peptidoglycan synthesis e. To add amino sugar to N-acetyl muramic acid
4. Aminoglycosides a. Are bacteriostatic
– bacteriocidal inhibitor of protein synthesis via 30s binding b. Bind to receptors on the 40S subunit of the bacterial ribosome – 30S c. Are well absorbed after oral administration d. Generally reach high levels in CSF e. Are ineffective as monotherapy against streptococci – need cell wall active drug like vancomycin for synergism
5. Which of the following drugs acts as an antimicrobial agent by blocking the attachment of IRNA molecules to ribosomes? a. Gentamicin b. Penicillin c. Chloramphenicol d. Tetracycline <= e. Clindamycin
6. The incidence of aplastic anaemia following use of chloramphenicol is approximately a. 1 in 100 (1%) b. 1 in 500 (0.2%) c. 1 in 1000 (0.1%) d. 1 in 10000 (0.01%) e. 1 in 30000 (0.003%) <= 1/25,000
– 1/40,000 (also causes gray baby syndrome)
7. Isoniazid a. Is a second line drug for the treatment of TB

b. Acts by inhibition of DNA gyrase – pyridoxine-like, inhibits mycobacteral cell walls c. Causes clinical hepatitis in 1% of recipients <= also neurotox (need pyridoxine) and inhibits metabolism of other drugs d. Is active only against M tuberculosis organisms which are extracellular – penetrates cells e. Causes an irreversible neuropathy – reversible with pyridoxine
8. With regards to penicillin a. Concentrations in most tissues are equal to serum <= true b. Mostly excreted by glomerular filtration
– 10% vs 90% secretion c. Half life is 2 hours – 30mins (is 30mins-1hour for most) d. Does not need to be adjusted in renal failure – does b/c secretion e. Can be used for enterococcal meningitis
9. With respect to antiviral therapy a. Indinovir is a reverse transcriptase inhibitor – protease inhibitor (antiHIV, I ggy P op) b. Acyclovir is only effective against herpes simplex and varicella zoster virus
– this is true for in vivo, it has only in vito activity against EBV and CMV c. Zidovudine (AZT) is a reverse transcriptase inhibitor and can only be administered orally – can be given oraaly and is an NRTI d. Protease inhibitors prevent uncoating of viral nucleic acids – prevent assembly of infectious viron core e. Valacyclovir is converted to acyclovir when taken orally <= true
10. Which drug causes hypoprothrombinaemia and bleeding disorders? a. Cefotetan <= also cefamandole and cefoperazone, these three can also cause disulfiram-like reaction like trimethoprim and metronidazole (inhibition of aldehyde dehydrogenase w/ accumulation of acetaldehyde -> flushing , N&V, HA) b. Cephalexin c. Cefotaxime d. Cefaclor e. Ceftazidime
11. acyclovir a. dose is 12-20mg five times daily – 200-800mg 5x/day (short t ½ 2.5-3h) b. does not work on viruses with thymidine kinase – this is required for the initial viral specific phosphorylation of acyclovir, and strains without are cross resistant to acyclovir and ganciclovir c. does not work on CMV – true in vivo d. is a guanasine analogue <= guanosine derivative e. ?
12. metronidazole a. is shown to be teratogenic in humans – animal studies, no evidence in humans b. causes a disulfiram-like reaction <= true c. inhibits alcohol dehydrogenase – acetaldehyde =(aldehyde dehydrogenase)=> acetate d. is recommended as a single dose for giardiasis e. ?
13. Which of the following is a cell wall inhibitor? a. Cephalosporins <= b. Tetracycline – 30s, inhibit tRNA to acceptor site or mRNA/ribosome complex, bacteriostatic c. Ciprofloxacin
– fluroquinolone, DNA gyrase

d. ? e. ?
14. tetracycline a. may cause photosensitivity <= b. does not cause enamel discolouration
– Ca2+ chelates c. ? d. ? e. ?
15. gentamicin a. is water soluble but unstable in solution b. is an antibiotic which is oxygen dependent <= correct c. ? d. ? e. ?
16. which antibiotic is resistant to beta-lactamase? a. Piperacillin
– and ticarcillin are anti-pseudomonas (Gram-ve bacilli) b. Cloxacillin <= anti-staph penicillins include methicillin (interstitial nephrtitis), nafcillin, oxacillin and the isoxazolyl penicillins cloxacillin, dicloxacillin, flucloxacillin c. Amoxicillin – ampicillin are extended spectrum but still b-lactamase suceptable (hence use w/ blactam inhibitos like clavulanic acid) d. Penicillin e. ?
17. Regarding trimethoprim, which is INCORRECT? a. Synergistic with sulphonamides - sequential synergism b. Folate synthesis disruption - true c. Less toxic to humans than to bacteria - true d. Is bacteriocidal <= bacteriostatic e. ?
18. aminoglycosides a. resistance is plasmid mediated <= true b. does not cross species c. ? d. ? e. ?
19. Which is INCORRECT? a. Disinfectants clean non-living fields b. Antiseptics clean living fields c. Antiseptics in low dose can promote bacterial growth <= correct d. Alcohol kills all bacteria and spores- not sporocidal e. ?
20. Penicillin G a. Hypernatraemia is not reported b. Has good penetration to the eye – eye, prostate and normal CNS is poor c. 100000u intrathecally can cause seizures <= d. 50% of people who clain allergy will have an allergic reaction on further exposure
– ‘small number’

e. ?
21. metronidazole a. commonly causes constipation – nausea, diarrhoea, hairy back tongue, headache, insomnia.. b. inhibits alcohol dehydrogenase – aldehyde dehydrogenase c. is useful in treatment of urogenital trichomonas
– antiprotozoal, treatment of choice of C. dif, also in
H.pylori, anti bacteriodes d. ? e. ?
22. erythromycin a. is predominantly renally excreted
– biliary secretion t1/2 2hr b. is a cell wall inhibitor
– 50S inhibitor c. is bacteriostatic only – in high conc bacteriocidal d. is effective against Campylobacter jejuni <= e. ?
23. Which antiseptic is commonly used in medical practice? a. Ethyl alcohol 70% <= need 60-90% to be effective b. Ethanol 30% c. Formaldehyde d. Isopropyl alcohol 10% e. All of the above
24. penicillins reach high concentrations in a. vitreous humour
– nots eye, prostate or normal CNS b. CSF with normal meninges – only when inflammed c. Proximal tubular fluid in kidneys <= d. ? e. ?
25. All are cell wall inhibitors EXCEPT: a. Vancomycin b. Erythromycin <= 50S c. Penicillin d. Ceftriaxone e. Imipenem
26. Regarding erythromycin a. It has a large cross reactivity with penicillin b. It is bacteriostatic only c. It is ineffective against Gram positive organisms d. It is inactivated by beta-lactamases e. It binds to the 50S subunit on the bacterial ribosome <=
27. Regarding metronidazole, all of the following are true EXCEPT: a. It is useful against trichomonas b. Is used to treat garnerella c. Causes a metallic taste in the mouth d. Inhibits alcohol dehydrogenase <= aldehyde dehydrogenase e. Is used to treat giardiasis
28. Which skin antiseptic is commonly used?

a. Ethyl alcohol 70% <= must be 60-90% b. Ethanol 30% c. Isopropyl alcohol 10% d. Formaldehyde e. Boric acid 5%
29. Acyclovir is active against all of the following EXCEPT: a. Herpes simplex b. CMV <= only in vivo c. Herpes zoster d. Varicella e. ?
30. A woman aged 43 presents with a petechial rash on her legs and a platelet count of 8,000. She has recently been receiving treatment for an ear infection. Which of these agents is MOST likely to be the cause of her current problems? a. Penicillin b. Amoxycillin c. Cotrimoxazole <= as folate blocking agents can cause thrombocytopaenia, granulocytopaenia, aplastic/megaloblastic anaemia d. Erythromycin e. Roxythromycin
31. Which of the following does NOT act primarily by inhibiting protein synthesis? a. Gentamicin b. Vancomycin <= D-Ala-D-Ala binding c. Erythromycin d. Clindamycin e. Chloramphenicol
32. Which of the following is a contraindication to the use of griseofulvin? a. Diabetes mellitus b. Multiple myeloma c. Porphyria <= (an antifungal) d. Alcoholic hepatic cirrhosis e. Sickle cell disease
33. with respect to hypersensitivity reactions to penicillins: a. if a patient has had a previous reaction to penicillin, the risk of allergic reaction is greater than 80% b. small children are at higher risk of allergic reaction to penicillin c. less than 1% of patients with a past history of having taken penicillin without reaction will have an allergic reaction <= d. the risk of sensitization is not related to the amount of penicillin received in the past e. ceftriaxone is a safe alternative for those with a past history of anaphylaxis to penicillin
34. which of the following is NOT true for norfloxacin? a. It is poorly absorbed from the gastrointestinal tract <= b. It is effective in salmonella enteritis c. It inhibits DNA synthesis in susceptible microbes – fluroquinalone so blocks DNAgyrase d. It can increase serum theophylline levels if administered concurrently e. It is mainly excreted by the kidney – true, secreted (and can be blocked by probenecid)
35. which of the following is NOT an adverse effect of gentamycin?

a. Haemolytic anaemia <= b. Prolonged neuromuscular blockade c. Eighth cranial nerve damage d. Impairment of renal function e. Vestibular damage
36. A 25 year old woman being treated for pneumonia develops clinical jaundice. Her serum bilirubin level is 40 micromoles per litre (normal up to 17) with a conjugated bilirubin level of 30 micromole per litre (normal up to 7). Which antibiotic is MOST likely to have caused this effect? a. Vancomycin b. Ceftriaxone c. Penicillin d. Doxycycline e. Erythromycin <= liver tox and can cause acute cholestatic hepatitis
37. cephalosporins a. promote cross linking in bacterial cell walls b. bind to penicillin binding proteins <= c. increase peptidoglycan synthesis d. promote the transpeptidation reaction e. are inactive in the synthesizing cell wall
38. macrolide antibiotics a. are usually active against Neiserria species <= b. are bacteriostatic but not bactericidal – in high doses are c. bind at the 30S ribosome subunit
– 50S d. are unaffected by plasmid mediated resistance e. enhance metabolism by cytochrome pathways - inhibit
39. which of the following is a second generation cephalosporin? a. Cefaclor <= b. Ceftazidime – 3rd c. Cephalexin
– 1 st w/ cefazolin d. Cefotaxime – 3rd e. Cephalothin – 1st
40. the cephalosporin with the higest activity agains gram positive bacteria is a. cefuroxime b. cefotaxime c. cefaclor d. cefipime e. cephalothin <= 1st
41. Which of the following antibiotics does not possess a beta-lactam ring? a. Penicillins b. Cephalosporins c. Fluoroquinilones <= DNA gyrase inhibitor d. Carbapenems e. Monobactams
42. Which of the following drugs does not exert its action by inhibiting cell wall synthesis? a. Vancomycin b. Erythromycin <= 50S c. Penicillin d. Ceftriaxone

e. Imipenem
43. Erythromycin a. Has a large cross-reactivity with the penicillins b. Is bacteriostatic only c. Is ineffective against gram positive organisms d. Is inactivated by beta lactamases e. Binds to the 50S subunit of the bacterial ribosome <=
44. Metronidazole a. Inhibits alcohol dehydrogenase – aldehyde dehydrogenase b. Is effective for vaginal trichomoniasis <= c. Does not cause a metallic taste in the mouth d. Turns urine green e. ?
45. penicillins reach high concentrations in a. vitreous humour b. CSF with normal meninges c. Proximal tubular fluid in kidneys <= d. ? e. ?
46. zidovudine (AZT) a. has a short half life <= b. inhibits viral thymidine kinase
– NRTI: are prodruges converted to active drug by the kinase, then inhibit the reverse transcriptase c. has no activity against retroviruses d. ? e. ?
47. The antiviral drug which acts on reverse transcriptase is a. Acyclovir - no b. Zidovudine <= NRTI c. Ganciclovir – similar to acyclovir (but also CMV) d. Vidarabine e. All of the above
48. acyclovir a. is commonly given in doses of 10-20mg tds b. is used to treat CMV c. is a guanosine analogue <= d. acts to inhibit viral entry into cells e. is only available intravenously
49. amantadine a. is an antiviral drug b. produces insomnia not sedation c. causes acute psychosis d. potentiates dopaminergic function e. all of the above <=

50. doxycycline a. acts to inhibit nucleic acid synthesis
– binds 50S so protein synthesis b. may cause photosensitivity <= true c. ? d. ? e. ?
51. all of the following inhibit nucleic acid synthesis EXCEPT: a. norfloxacin
– blocks DNAgyrase b. trimethoprim - true c. rifampicin – anti TB, blocks RNA polymerase d. sulfasalazine
– sulfonamide, used for inflammorty condistion like IBS e. chloramphenicol <= 50s blocker
52. gentamicin a. is not nephrotoxic b. decreases the effect of neuromuscular junction blocking drugs c. may be given orally d. enters cells by an oxygen dependent influx <= e. has a large therapeutic index
53. Which of the following is not true of trimethoprim a. It is useful in the treatment of UTI b. It is bactericidal - bacteriostatic c. It is an antifolate antimetabolite drug d. ? e. ?
54. A patient with impetigo would be most likely to respond to a. Streptomycin b. Kanamycin c. Metronidazole d. Cephalexin
– 1 st gen cephalosporin e. Phenoxymethylpenicillin