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Question 1
Incorrect
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All of the following statements regarding metronidazole are correct except:
Your Answer: Dose-dependent gastrointestinal upset is a common adverse effect.
Correct Answer: Metronidazole reduces the anticoagulant effect of warfarin.
Explanation:The anticoagulant effect of warfarin is enhanced by metronidazole. If use of both cannot be avoided, one must consider appropriately reducing the warfarin dosage. With alcohol, metronidazole can cause a disulfiram-like reaction, with symptoms like flushing, headaches, dizziness, tachypnoea and tachycardia, nausea and vomiting. The common side effects of metronidazole include a metallic taste and gastrointestinal irritation, in particular nausea and vomiting. These side effects are more common at higher doses. This drug has high activity against anaerobic bacteria and protozoa, and is well absorbed orally. For severe infections, the intravenous route is normally reserved.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 2
Incorrect
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An elderly female has a bacterial infection and you are asked to prescribe an antibiotic to her. This antibiotic is a nucleic acid synthesis inhibitor.
Which of the following antimicrobial drugs will be prescribed to this patient?Your Answer: Vancomycin
Correct Answer: Metronidazole
Explanation:Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors.
Erythromycin inhibits protein synthesis and blocks translocation by binding to the 23S rRNA of the 50S ribosomal subunit.
Chloramphenicol blocks peptidyl transferase at 50S ribosomal subunit.
Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA and thus preventing initiation of protein synthesis.
An overview of the different mechanisms of action of the various types of antimicrobial agents is shown below:
1. Inhibition of cell wall synthesis
– Penicillins
– Cephalosporins
– Vancomycin
2. Disruption of cell membrane function
– Polymyxins
– Nystatin
– Amphotericin B
3. Inhibition of protein synthesis
– Macrolides
– Aminoglycosides
– Tetracyclines
– Chloramphenicol
4. Inhibition of nucleic acid synthesis
– Quinolones
– Trimethoprim
– 5-nitroimidazoles
– Rifampicin
5. Anti-metabolic activity
– Sulphonamides
– Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 3
Incorrect
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You examine a 34-year-old lady with symptoms that are consistent with acute sinusitis. You're thinking about giving her doxycycline for treatment.
What is doxycycline's mechanism of action?Your Answer: Inhibition of cell wall synthesis
Correct Answer: Inhibition of protein synthesis
Explanation:Doxycycline and other tetracycline antibiotics attach to the 30S subunit of the bacterial ribosome, preventing aminoacyl-tRNA binding and so protein synthesis beginning.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 4
Incorrect
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Regarding aciclovir, which of the following statements is INCORRECT:
Your Answer: Neurotoxicity, including tremor, delirium, and seizures, may develop without adequate patient hydration in patients taking aciclovir.
Correct Answer: Aciclovir eradicates herpes simplex virus from the body.
Explanation:Aciclovir is active against herpesviruses but does not eradicate latent virus.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 5
Incorrect
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A 23-year-old student presents to the emergency department with a terrible headache, photophobia, and a fever. On her lower limbs, you see a non-blanching purpuric rash. In the department, a lumbar puncture is conducted. What do you think you'll notice on Gram stain:
Your Answer: Gram positive diplococci
Correct Answer: Gram negative diplococci
Explanation:Bacterial meningitis and septicaemia are most commonly caused by meningococcal bacteria. The Gram-negative diplococci Neisseria Meningitidis causes meningitis. Gram stain and culture of CSF identify the etiologic organism, N meningitidis. In bacterial meningitis, Gram stain is positive in 70-90% of untreated cases, and culture results are positive in as many as 80% of cases.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 6
Incorrect
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Herpes simplex encephalitis has a predilection for which of the following sites:
Your Answer: Occipital lobe
Correct Answer: Temporal lobe
Explanation:Herpes simplex virus is the most common cause of infective encephalitis and has a predilection for the temporal lobes. Herpes simplex is transmitted through direct contact. It invades skin locally producing skin vesicles by its cytolytic activity.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 7
Correct
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Fusidic acid is primarily indicated for infections caused by which of the following microorganisms:
Your Answer: Staphylococcal infections
Explanation:Fusidic acid is a narrow spectrum antibiotic used for staphylococcal infections, primarily topically for minor staphylococcal skin (impetigo) or eye infection. It is sometimes used orally for penicillin-resistant staphylococcal infection, including osteomyelitis or endocarditis, in combination with other antibacterials.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 8
Correct
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A 23 year old student presents to ED with a widespread maculopapular rash. She recently had a sore throat and was started on a course of antibiotics. The most likely antibiotic that she was prescribed is:
Your Answer: Amoxicillin
Explanation:Maculopapular rashes are commonly seen with ampicillin and amoxicillin. However they are not usually related to true penicillin allergy. Very often, they occur in patients with glandular fever and so, broad-spectrum penicillins should not be used blindly, for management and treatment of a sore throat. There is also an increased risk of rash in patients with acute or chronic lymphocytic leukaemia or in cytomegalovirus infection.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 9
Incorrect
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Regarding penicillin antibiotics, which of the following statements is CORRECT:
Your Answer: Almost all patients with a true penicillin allergy will also be allergic to cephalosporins.
Correct Answer: Patients with a history of atopy are at higher risk of hypersensitivity reactions.
Explanation:Allergic reactions to penicillins occur in 1 – 10% of exposed individuals; anaphylactic reactions occur in fewer than 0.05% of treated patients. Patients with a history of atopic allergy are at higher risk of anaphylactic reactions to penicillins. Patients with a history of anaphylaxis, urticaria, or rash immediately after penicillin use should not receive a penicillin or other beta-lactam antibiotics; about 0.5 – 6.5 % of penicillin-sensitive patients will also be allergic to the cephalosporins.
Patients with a history of a more minor rash (i.e. non-confluent, non-pruritic rash restricted to a small area of the body) or delayed reaction (rash occurring more than 72 hours after penicillin administration), may not be truly allergic and may be considered for penicillin or beta-lactam treatment in severe infection (although possibility of allergy should be borne in mind). Other beta-lactam antibiotics (including cephalosporins) can be used in these patients.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 10
Correct
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A 63 year old lady presents to ED with a persistent cough and red currant jelly sputum. She has a history of chronic alcohol abuse and has an X-ray which demonstrates a cavitating pneumonia. The most likely causative pathogen is:
Your Answer: Klebsiella pneumoniae
Explanation:One of the results of Klebsiella pneumoniae is pneumonia that is usually a very severe infection. It is characterised by thick, bloody sputum (red currant jelly sputum), and is associated with complications like lung abscess, cavitation, necrosis, empyema and pleural effusions.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 11
Correct
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A 50-year-old man presents with signs and symptoms of an anaphylactic reaction. His GP had recently given him a new medication.
Which one of these is the most likely medication responsible for the drug-induced anaphylactic reaction?
Your Answer: Penicillin
Explanation:The most common cause of drug-induced anaphylaxis is penicillin.
The second commonest cause are NSAIDs. Other drugs associated with anaphylaxis are ACE inhibitors and aspirin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 12
Incorrect
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Co-amoxiclav is used first line for which of the following indications:
Your Answer: Osteomyelitis
Correct Answer: Animal bite
Explanation:Co-amoxiclav is used first line for infected and prophylaxis of infection in animal and human bites.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 13
Correct
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Which of the following infections is vancomycin most likely prescribed for?
Your Answer: Clostridium difficile colitis
Explanation:125 mg PO q6hr for 10 days is indicated for treatment of Clostridium difficile (C. difficile)-associated diarrhoea
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 14
Incorrect
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Doxycycline is indicated first line for treatment of which of the following infections:
Your Answer: Gonorrhoea
Correct Answer: Chlamydia
Explanation:Doxycycline may be used first line for chlamydia, pelvic inflammatory disease (with metronidazole and ceftriaxone), acute bacterial sinusitis, exacerbation of chronic bronchitis, moderate-severity community acquired pneumonia and high-severity community acquired pneumonia (with benzylpenicillin).
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 15
Correct
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During her pregnancy, a 28-year-old lady was given an antibiotic. The neonate is born with bilateral deafness as a result of this.
From the following antibiotics, which one is most likely to cause this side effect?Your Answer: Gentamicin
Explanation:Aminoglycosides cross the placenta and are linked to poisoning of the 8th cranial nerve in the foetus, as well as permanent bilateral deafness.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 16
Correct
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A 30-year-old woman presents with a history of fever and sore throat. On examination, there is tonsillar exudate and cervical lymphadenopathy and a diagnosis of tonsillitis is made. A course of penicillin is prescribed.
What is the mechanism of action of penicillin?
Your Answer: Inhibition of cell wall synthesis
Explanation:Penicillin is bactericidal and produces its antimicrobial action by preventing cross-linkage between the linear peptidoglycan polymer chains that make up the bacterial cell wall. This action inhibits cell wall synthesis.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 17
Incorrect
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Regarding flucloxacillin, which of the following statements is CORRECT:
Your Answer: It is used first line for localised impetigo infection.
Correct Answer: It is resistant to bacterial beta-lactamases.
Explanation:Flucloxacillin is unique in that it is beta-lactamase stable and it can be used in infections caused by beta-lactamase producing staphylococci e.g. S. aureus. It is acid-stable and can therefore be given by mouth as well as by injection. It is used first line for treatment of widespread impetigo infection, cellulitis, mastitis, osteomyelitis, septic arthritis, severe erysipelas, severe/spreading otitis externa and infective endocarditis caused by staphylococci. The most common adverse effects of flucloxacillin include nausea, vomiting, skin rash, and diarrhoea. Cholestatic jaundice and hepatitis may occur very rarely, up to two months after treatment with flucloxacillin has been stopped. Administration for more than 2 weeks and increasing age are risk factors. First line treatment of animal and human bites is co-amoxiclav.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 18
Correct
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Flucloxacillin is used first line for all of the following infections EXCEPT for:
Your Answer: Otitis media
Explanation:Flucloxacillin is used first line for treatment of widespread impetigo infection, cellulitis, mastitis, osteomyelitis, septic arthritis, severe erysipelas, severe/spreading otitis externa and infective endocarditis caused by staphylococci. Amoxicillin is first line for acute otitis media.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 19
Incorrect
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A 6-year-old girl is brought into the paediatric emergency room by her mother in a state of high-grade fever and extreme irritability. She is also reluctant to urinate as it is associated with lower abdominal pain and stinging. She has no history of any UTIs requiring antibiotics in the past 12 months.
The urine sensitivity test report is still unavailable. A clean catch urine sample is taken for urine dipstick, which reveals the presence of blood, protein, leukocytes and nitrites. Fresh blood tests were sent, and her estimated GFR is calculated to be 40 ml/minute.
Out of the following, which antibiotic is most appropriate to be prescribed to this patient?Your Answer: Co-amoxiclav
Correct Answer: Trimethoprim
Explanation:The NICE guidelines for children and young people under 16 years lower UTIs are:
1. Get a urine sample before antibiotics are taken, and do a dipstick test OR send for culture and susceptibility
2. Assess and manage children under 5 with lower UTI with fever as recommended in the NICE guideline on fever in under 5s.
3. Prescribe an immediate antibiotic prescription and take into account the previous urine culture and susceptibility results, previous antibiotic use, which may have led to resistant bacteria
4. If urine culture and susceptibility report is sent
– Review the choice of antibiotic when the results are available AND
– change the antibiotic according to susceptibility results if the bacteria are resistant and symptoms are not improving, using a narrow-spectrum antibiotic wherever possibleThe choice of antibiotics for non-pregnant young people under 16 years with lower UTI is summarised below:
1. Children under 3 months:
– Refer to paediatric specialist and treat with intravenous antibiotic in line with NICE guideline on fever in under 5s
2. Children over 3 months:
– First-choice
Nitrofurantoin – if eGFR >45 ml/minute
Trimethoprim – (if low risk of resistance*)
– Second-choice (no improvement in lower UTI symptoms on first-choice for at least 48 hours, or when first-choice not suitable)
Nitrofurantoin – if eGFR >45 ml/minute and not used as first-choice
Amoxicillin (only if culture results available and susceptible)
Cefalexin -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 20
Incorrect
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A 39-year-old man who is suffering from a bacterial infection require antibiotic treatment. You need to figure out which antibiotic is most suitable. Listed below are antimicrobial drugs.
Which one is a nucleic acid synthesis inhibitor?
Your Answer: Vancomycin
Correct Answer: Ciprofloxacin
Explanation:Ciprofloxacin and other quinolone antibiotics work by blocking DNA gyrase, an enzyme that compresses bacterial DNA into supercoils, as well as a type II topoisomerase, which is required for bacterial DNA separation. As a result, they prevent nucleic acid synthesis.
The following is a summary of the many modes of action of various types of antimicrobial agents:Action Mechanisms- Examples:
Cell wall production is inhibited
Vancomycin
Vancomycin
CephalosporinsThe function of the cell membrane is disrupted
Nystatin
Polymyxins
Amphotericin BInhibition of protein synthesis
Chloramphenicol
Macrolides
Aminoglycosides
TetracyclinesNucleic acid synthesis inhibition
Quinolones
Trimethoprim
Rifampicin
5-nitroimidazoles
Sulphonamides
Anti-metabolic activity
Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 21
Correct
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In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic is a protein synthesis inhibitor.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer: Gentamicin
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA and thus preventing initiation of protein synthesis.
Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors.
Penicillins and cephalosporins are the major antibiotics that inhibit bacterial cell wall synthesis. They inactivate transpeptidases that help cross-link peptidoglycans in cell walls.
Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Ciprofloxacin inhibits prokaryotic enzymes topoisomerase II (DNA gyrase) and topoisomerase IV.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 22
Correct
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For which of the following infections is phenoxymethylpenicillin (penicillin V) primarily used?
Your Answer: Streptococcal tonsillitis
Explanation:Phenoxymethylpenicillin (penicillin V) is less active than benzylpenicillin but both have similar antibacterial spectrum. Because penicillin V is gastric-acid stable, it is suitable for oral administration, but should not be used for serious infections as absorption can be unpredictable and plasma concentrations can be variable.
Its uses are:
1. mainly for respiratory tract infections in children
2. for streptococcal tonsillitis
3. for continuing treatment after one or more injections of benzylpenicillin when clinical response has begun.
4. for prophylaxis against streptococcal infections following rheumatic fever and against pneumococcal infections following splenectomy or in sickle-cell disease.It should not be used for meningococcal or gonococcal infections.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 23
Correct
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A patient who shows symptoms of infection and is admitted under supervision of the medical team. The organism which caused this, is a Gram-negative bacterium, according to the culture. A penicillin therapy is suggested by the microbiologist.
Which of the penicillins listed below is the most effective against Gram-negative bacteria?Your Answer: Amoxicillin
Explanation:Amoxicillin and Ampicillin are more hydrophilic (broad-spectrum) penicillins than benzylpenicillin and phenoxymethylpenicillin. Because they may penetrate through gaps in the outer phospholipid membrane, they are effective against Gram-negative bacteria. Amoxicillin and Ampicillin are resistant to penicillinase-producing microbes.
Community-acquired pneumonia, otitis media, sinusitis, oral infections, and urinary tract infections are among the most prevalent conditions for which they are prescribed. The normal adult oral dose of Amoxicillin is 500 mg three times/day, which can be increased to 1 g three times/day if necessary. Ampicillin is given to adults in doses of 0.5-1 g every 6 hours.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 24
Correct
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Regarding drug interactions with erythromycin, which of the following statements is INCORRECT:
Your Answer: Erythromycin decreases plasma levels of warfarin.
Explanation:Erythromycin and clarithromycin inhibit cytochrome P450-mediated metabolism of warfarin, phenytoin and carbamazepine and may lead to accumulation of these drugs. There is an increased risk of myopathy (due to cytochrome P450 enzyme CYP3A4 inhibition) if erythromycin or clarithromycin is taken with atorvastatin or simvastatin. Erythromycin increases plasma concentrations of theophylline, and theophylline may also reduce absorption of oral erythromycin. All macrolides can prolong the QT-interval and concomitant use of drugs that prolong the QT interval is not recommended.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 25
Incorrect
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Question 26
Incorrect
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Regarding amoxicillin, which of the following statements is INCORRECT:
Your Answer: Amoxicillin absorption is not affected by the presence of food in the stomach.
Correct Answer: It is used first line for bacterial tonsillitis.
Explanation:Amoxicillin is a derivative of ampicillin and has a similar antibacterial spectrum. It is better absorbed than ampicillin when given orally, producing higher plasma and tissue concentrations; unlike ampicillin, absorption is not affected by the presence of food in the stomach.
The adverse effects of amoxicillin are mainly gastrointestinal and mild and include nausea, vomiting and diarrhoea. Amoxicillin is used first line for low to moderate severity community acquired pneumonia, exacerbations of chronic bronchitis, for acute otitis media, for acute sinusitis, for oral infections/dental abscess, for Listeria meningitis (in combination with another antibiotic), for infective endocarditis (in combination with another antibiotic) and for H. Pylori eradication (in combination with metronidazole/clarithromycin and a PPI).
Penicillin V is used first line for bacterial tonsillitis; amoxicillin should be avoided in blind treatment of a sore throat as there is a high risk of a rash if glandular fever is present.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 27
Correct
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Regarding co-amoxiclav, which of the following statements is INCORRECT:
Your Answer: Clavulanic acid acts to inhibit cross-linking of bacterial peptidoglycan polymers.
Explanation:Co-amoxiclav consists of amoxicillin with the beta-lactamase inhibitor clavulanic acid. Clavulanic acid itself has no significant antibacterial activity but, by inactivating beta-lactamases, it makes the combination active against beta-lactamase-producing bacteria that are resistant to amoxicillin.The most common adverse effects of co-amoxiclav include nausea, vomiting, skin rash and diarrhoea. Pseudomembranous colitis should be considered if a person develops severe diarrhoea during or after treatment with co-amoxiclav. Cholestatic jaundice can occur either during or shortly after the use of co-amoxiclav. An epidemiological study has shown that the risk of acute liver toxicity was about 6 times greater with co-amoxiclav than with amoxicillin. Cholestatic jaundice is more common in patients above the age of 65 years and in men; these reactions have only rarely been reported in children. Jaundice is usually self-limiting and very rarely fatal.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 28
Incorrect
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What is the mechanism of action of penicillin antibiotics:
Your Answer: Inhibition of bacterial nucleic acid synthesis
Correct Answer: Inhibition of bacterial cell wall synthesis
Explanation:Penicillins and the other ß-lactam antibiotics are bactericidal. They produce their antimicrobial action by preventing cross-linkage between the linear peptidoglycan polymer chains that make up the bacterial cell wall. They, therefore, inhibit cell wall synthesis.
The integrity of the ß-lactam ring is essential for antimicrobial activity. Many bacteria (including most Staphylococci) are resistant to benzylpenicillin and phenoxymethylpenicillin because they produce enzymes (penicillinases, ß-lactamases) that open the ß-lactam ring. -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 29
Correct
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In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic is an inhibitor of cell wall synthesis.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer: Benzylpenicillin
Explanation:Penicillins and cephalosporins are the major antibiotics that inhibit bacterial cell wall synthesis. They inactivate transpeptidases that help cross-link peptidoglycans in cell walls.
Isoniazid decreases the synthesis of mycolic acids in mycobacterium.
Clarithromycin binds to the 50S subunit of ribosomes and inhibits protein synthesis.
Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Tetracycline bind to 30S and prevent attachment of aminoacyl-tRNA.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 30
Correct
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Streptococcus viridans has developed subacute bacterial endocarditis in your patient. Which of the following locations is most likely to be the organism's origin?
Your Answer: Oral cavity
Explanation:Streptococci that are alpha-haemolytic, such as Streptococcus viridans, are major components of the flora in the oral cavity.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 31
Incorrect
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Amoxicillin is used first line for all of the following infections EXCEPT for:
Your Answer: Infective exacerbation of chronic bronchitis
Correct Answer: Cellulitis
Explanation:Amoxicillin is used first line for low to moderate severity community acquired pneumonia, exacerbations of chronic bronchitis, for acute otitis media, for acute sinusitis, for oral infections/dental abscess, for Listeria meningitis (in combination with another antibiotic), for infective endocarditis (in combination with another antibiotic) and for H. Pylori eradication (in combination with metronidazole/clarithromycin and a PPI). Flucloxacillin is used first line for acute cellulitis.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 32
Incorrect
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Which of the following side effects would you least associated with ciprofloxacin:
Your Answer: QT-interval prolongation
Correct Answer: Folate deficiency
Explanation:Common side effects include diarrhoea, dizziness, headache, nausea and vomiting.
Other adverse effects include: Tendon damage (including rupture), Seizures (in patients with and without epilepsy), QT-interval prolongation, Photosensitivity and Antibiotic-associated colitis -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 33
Incorrect
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A 6-year-old child with a few itchy honey crusted sores on her left cheek is brought in by her mother. Following a thorough examination of the child, you diagnose impetigo and recommend a course of topical fusidic acid.
Fusidic acid's mode of action is which of the following?Your Answer: Forming pores that disrupt the cell membrane
Correct Answer: Inhibition of protein synthesis
Explanation:By binding EF-G-GDP, fusidic acid prevents both peptide translocation and ribosome disassembly, which slows protein synthesis. Because it has a novel structure and mechanism of action, it is unlikely to cause cross-resistance with existing antibiotics.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 34
Correct
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A 78-year-old man develops renal impairment and hearing loss after inpatient management for sepsis.
Which of these antibiotics is most likely to have been used?Your Answer: Gentamicin
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA, and thus prevents initiation of protein synthesis.
Two of its most notable side effects are reversible nephrotoxicity(caused by the inhibition of protein synthesis in renal cells, which causes acute tubular necrosis) and hearing loss (caused by damage to the vestibular apparatus of the inner ear).
Both side effects are dose-related and occur commonly in the elderly.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 35
Incorrect
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Which of the following bacteria is a rod-shaped, oxidase-positive, opportunistic gram-negative bacteria that can cause a catheter-related urinary tract infection (UTI)?
Your Answer: Staphylococcus aureus
Correct Answer: Pseudomonas aeruginosa
Explanation:Listeria monocytogenes is a gram-positive bacteria that does not produce spores.
Staphylococcus aureus is a gram-positive bacteria, while Candida albicans is a gram-positive yeast with a single bud.
Among the choices, gram-negative bacteria include only Klebsiella pneumoniae and Pseudomonas aeruginosa.
Pseudomonas aeruginosa is an oxidase-positive bacterium, while Klebsiella pneumoniae is an oxidase-negative bacterium.
P. aeruginosa can cause urinary tract infections (UTIs) and is spread through poor hygiene or contaminated medical equipment or devices, such as catheters that haven’t been fully sterilized.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 36
Incorrect
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You review a patient with urinary sepsis and decide to start her on gentamicin.
Which statement about gentamicin is true?
Your Answer:
Correct Answer: Ototoxicity is a dose-related effect
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA, and thus prevents initiation of protein synthesis.
Gentamicin is given by injection because it is NOT absorbed orally.
It is excreted in the kidneys by glomerular filtration
Gentamicin is not to be used for the treatment of Neisseria meningitidis, Neisseria gonorrhoea, or Legionella pneumophila.There is a risk of patient going into shock from lipid A endotoxin release.
Two of its most notable side effects are hearing loss reversible nephrotoxicity and which are both dose-related and levels should be monitored in patients.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 37
Incorrect
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A 73-year-old woman arrives at the emergency department 48 hours after being discharged from the hospital after a two-week stay for sepsis treatment. She has fever, productive cough with thick green sputum, and shortness of breath. An X-ray shows left lower lobe pneumonia. Which of the bacteria listed below is more likely to be the causative agent:
Your Answer:
Correct Answer: Pseudomonas aeruginosa
Explanation:Hospital-acquired pneumonia (HAP), or nosocomial pneumonia, is a lower respiratory infection that was not incubating at the time of hospital admission and that presents clinically 2 or more days after hospitalization. Pneumonia that presents sooner should be regarded as community acquired pneumonia. VAP refers to nosocomial pneumonia that develops among patients on ventilators. Ventilator-associated pneumonia (VAP) is defined as pneumonia that presents more than 48 hours after endotracheal intubation.
Common bacteria involved in hospital-acquired pneumonia (HAP) include the following [10] :
Pseudomonas Aeruginosa
Staphylococcus aureus, including methicillin-susceptible S aureus (MSSA) and methicillin-resistant S aureus (MRSA)
Klebsiella pneumoniae
Escherichia coli -
This question is part of the following fields:
- Infections
- Microbiology
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Question 38
Incorrect
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Dysuria and urinary frequency are symptoms of a 29-year-old woman. A urine dipstick is used to detect the presence of blood, protein, leucocytes, and nitrites in the urine. You diagnose a urinary tract infection and give antibiotics to the patient.
In the United Kingdom, which of the following antibiotics has the highest percentage of E.coli resistance?Your Answer:
Correct Answer: Trimethoprim
Explanation:In the United Kingdom, antibiotic resistance is becoming a significant factor in the treatment of urinary tract infections and pyelonephritis. E. coli (the main causative organism of both urinary tract infections and acute pyelonephritis) resistance to the following antibiotics in laboratory-processed urine specimens is:
30.3 percent trimethoprim (varies by area from 27.1 to 33.4 percent )
19.8 percent co-amoxiclav (varies by area from 10.8 to 30.7 percent )
Ciprofloxacin (Cipro): 10.6% (varies by area from 7.8 to 13.7 percent )
Cefalexin has a concentration of 9.9%. (varies by area from 8.1 to 11.4 percent ) -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 39
Incorrect
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A 61-year-old patient experiences a spontaneous rupture of his Achilles tendon following a course of antibiotics
Which of the antibiotics listed below is MOST likely to be the cause?Your Answer:
Correct Answer: Ciprofloxacin
Explanation:Tendinopathy and spontaneous tendon rupture are caused by fluoroquinolones, which are an uncommon but well-known cause. Tendon problems caused by fluoroquinolones are expected to affect 15 to 20 people per 100,000. Patients over the age of 60 are most likely to develop them.
It usually affects the Achilles tendon, but it has also been described in cases involving the quadriceps, peroneus brevis, extensor pollicis longus, long head of biceps brachii, and rotator cuff tendons. The exact aetiology is uncertain, although the fluoroquinolone medication is thought to obstruct collagen activity and/or cut off blood supply to the tendon.
Other factors linked to tendon rupture spontaneously include:
Gout
Treatment with corticosteroids
Hypercholesterolaemia
Long-term dialysis
Kidney transplant
Rheumatoid arthritis -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 40
Incorrect
-
A 60-year-old male presents to the genitourinary clinic with dysuria and urinary frequency complaints. He has a past medical history of benign prostate enlargement, for which he has been taking tamsulosin. There is blood, protein, leucocytes, and nitrites on a urine dipstick. Fresh blood tests were sent, and his estimated GFR is calculated to be >60 ml/minute. A urinary tract infection (UTI) diagnosis is made, and he is prescribed antibiotics. Out of the following, which antibiotic is most appropriate to be prescribed to this patient?
Your Answer:
Correct Answer: Ciprofloxacin
Explanation:URINARY TRACT INFECTIONS IN ADULT MEN
Symptomatic urinary tract infections are much less common in men than in women, and all UTIs
in men are considered complicated UTIs. Men with UTIs should be evaluated for predisposing or
causative factors.Uncomplicated cystitis
- Fosfomycin, oral, 3 g as a single dose.
If fosfomycin is unavailable:
- Nitrofurantoin, oral, 100 mg 6 hourly for 5 days.
Do not use nitrofurantoin or fosfomycin if there is any suspicion of early pyelonephritis as they do
not achieve adequate renal tissue levels.
If there are any factors precluding the use of the above agents, then a beta-lactam should be used.
Options include:
Cefixime 200 mg PO 12 hourly for 7 days
OR
Cefpodoxime 100 mg PO 12 hourly for 7 daysComplicated cystitis
Adults- Ciprofloxacin 500 mg PO 12 hourly
OR - Levofloxacin 750 mg PO once daily
Empiric antibiotic therapy should be changed based upon the bacteria isolated and its
antimicrobial susceptibility.
Treat for a total of 7–14 days -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 41
Incorrect
-
A patient presents with a cough, productive of green sputum and fever. He was commenced on antibiotics 4 days earlier, but his condition has worsened. There is a documented history of penicillin allergy, and the GP prescribed erythromycin.
Erythromycin exert its pharmacological effect by binding to?
Your Answer:
Correct Answer: The 50S subunit of the bacterial ribosome
Explanation:Macrolides are bacteriostatic antibiotics. They act by binding to the 50S subunit of the bacterial ribosome and inhibit translocation, therefore, inhibiting protein synthesis.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 42
Incorrect
-
Cefotaxime (or ceftriaxone) is used first line for which of the following infections:
Your Answer:
Correct Answer: Blind treatment of suspected bacterial meningitis
Explanation:Cefotaxime (or ceftriaxone) are indicated first line in:
– Blind treatment of meningitis in patients > 3 months (with amoxicillin if patient > 50 years)
– Meningitis caused by meningococci
– Meningitis caused by pneumococci
– Meningitis caused by H. influenzae
– Severe or invasive salmonellosis
– Typhoid fever
– Gonorrhoea
– Gonococcal arthritis
– Haemophilus influenzae epiglottitis -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 43
Incorrect
-
In the Paediatric Emergency Department, you saw a 6-year-old girl with severe bilateral conjunctivitis. You give her mother some general eye hygiene advice and prescribe chloramphenicol eye drops.
What is the chloramphenicol's mechanism of action?
Your Answer:
Correct Answer: Inhibition of protein synthesis
Explanation:Chloramphenicol is a broad-spectrum antibiotic that inhibits bacterial protein synthesis by blocking the 50S subunit of the bacterial ribosome’s peptidyl transferase activity. When administered systemically, it has limited usage due to the potential of significant side effects such as aplastic anaemia, peripheral neuropathy, and optic neuritis. It’s only used to treat typhoid fever and Haemophilus influenzae meningitis, but it’s usually better to use a broad-spectrum cephalosporin.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 44
Incorrect
-
During her pregnancy, a 28-year-old lady was given an antibiotic. The neonate was prematurely born with cyanosis and ashen grey coloured skin as a result of this. Other symptoms were hypotonia, low blood pressure, and poor feeding.
From the following antibiotics, which one is most likely to cause this side effect?Your Answer:
Correct Answer: Chloramphenicol
Explanation:Grey baby syndrome is a rare but causes significant adverse effect caused by the build-up of chloramphenicol in neonates (particularly preterm babies).
The following are the main characteristics of ‘grey baby syndrome’:
Skin that is ashy grey in colour.
Feeding problems
Vomiting
Cyanosis
Hypotension
Hypothermia
Hypotonia
Collapse of the cardiovascular system
Distension of the abdomen
trouble breathing -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 45
Incorrect
-
A 35-year-old woman has complaints of nausea, abdominal pain and dark urine. On examination, you notice she has jaundice. She tells you she recently started a new medication.
Which drug is NOT likely to cause cholestatic jaundice out of the following?Your Answer:
Correct Answer: Isoniazid
Explanation:Isoniazid is an antibiotic used in the treatment of tuberculosis. It can cause acute, dose-dependent, hepatitis but is not a recognised cause of cholestatic jaundice.
The drugs that cause cholestatic jaundice are the following:
1. Nitrofurantoin
2. Erythromycin
3. Cephalosporins
4. Verapamil
5. NSAIDs
6. ACE inhibitors
7. Tricyclic antidepressants
8. Phenytoin
9. Azathioprine
10. Carbamazepine
11. Oral contraceptive pills
12. Diazepam
13. Ketoconazole
14. Tamoxifen -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 46
Incorrect
-
Regarding ampicillin, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Ampicillin may cause a widespread maculopapular rash in a patient with glandular fever.
Explanation:Ampicillin is a broad-spectrum antibiotic, active against certain Gram-positive and Gram-negative organisms but is inactivated by penicillinases (similar to amoxicillin in spectrum). Ampicillin is associated with high levels of resistance, therefore it is often not appropriate for blind treatment of infection. It is principally indicated for the treatment of exacerbations of chronic bronchitis and middle ear infections, both of which may be due to Streptococcus pneumoniae and H. influenzae, and for urinary tract infections.
Maculopapular rashes commonly occur with ampicillin (and amoxicillin) but are not usually related to true penicillin allergy. They almost always occur in patients with glandular fever; thus broad-spectrum penicillins should not be used for blind treatment of a sore throat. The risk of rash is also increased in patients with acute or chronic lymphocytic leukaemia or in cytomegalovirus infection.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 47
Incorrect
-
A 46-year-old male who is suffering from a chest infection. You decide to start giving the patient antibiotics, however he is allergic to penicillin. You consult with one of your co-workers about the best choice of antibiotic to give.
From the following choices, which is considered an example of bacteriostatic antibiotic?
Your Answer:
Correct Answer: Trimethoprim
Explanation:Antibiotics that are bactericidal kill bacteria, while antibiotics that are bacteriostatic limit their growth or reproduction. The antibiotics grouped into these two classes are summarized in the table below:
Bactericidal antibiotics
Bacteriostatic antibioticsVancomycin
Metronidazole
Fluoroquinolone, such as ciprofloxacin
Penicillins, such as benzylpenicillin
Cephalosporin, such as ceftriaxone
Co-trimoxazole
Tetracyclines, such as doxycycline
Macrolides, such as erythromycin
Sulphonamides, such as sulfamethoxazole
Clindamycin
Trimethoprim
Chloramphenicol -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 48
Incorrect
-
An 11-year-old presented to a GP with a history of headache, neck stiffness and photophobia. On examination, HR is 122, BP is 87/42, RR is 28, SaO 2 is 95%, temperature is 39.4 o C. There is a recent petechial rash on legs and arms. The GP administered a dose of antibiotics in the prehospital setting before transferring to the Emergency Department. Which of these would the GP have administered?
Your Answer:
Correct Answer: IM benzylpenicillin 1.2 g
Explanation:General Practitioners are advised to give a single injection of benzylpenicillin by intravenous or intramuscular injection before transferring the patient urgently to the ED when bacterial meningitis is suspected.
The recommended doses are:
Infants under 1 year: 300 mg
Children ages 1 to 9 years: 600 mg
Children aged 10 years and over: 1.2g
Adults: 1.2g -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 49
Incorrect
-
You're examining a 58-year-old male who has cellulitis in his left leg. Because he is allergic to penicillin, you start him on erythromycin.
Which of the following statements about erythromycin is correct?Your Answer:
Correct Answer: It can be used to treat Legionnaire’s disease
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolide antibiotics. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and thereby protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered to the infection site as a result.
Erythromycin is an orally active antibiotic that can also be given intravenously. It is metabolized in the liver and eliminated in the bile and has a biological half-life of 1.5 hours.
It has a similar antibacterial spectrum to benzylpenicillin (i.e., a narrow spectrum, primarily against Gram-positive pathogens) and can be used as a penicillin substitute in people who are allergic to penicillin.
Erythromycin is unsuccessful in the treatment of meningitis because it does not penetrate the central nervous system well enough. It is efficient against a variety of unusual pathogens, unlike penicillin. -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 50
Incorrect
-
A young female was diagnosed with a urinary tract infection and was sent home with medications. However, after 48 hours of discharge, she returned to the hospital because there had been no relief from her symptoms. She is pregnant in her second trimester.
The urine sensitivity test report is still unavailable. Fresh blood tests were sent, and her estimated GFR is calculated to be >60 ml/minute.
She was prescribed nitrofurantoin 100 mg modified-release orally twice a day for two days.
Out of the following, which antibiotic is most appropriate to be prescribed to this patient?Your Answer:
Correct Answer: Cefalexin
Explanation:The NICE guidelines for pregnant women with lower UTIs are:
1. Prescribe an antibiotic immediately, taking into account the previous urine culture and susceptibility results or avoiding past antibiotics that may have caused resistance
2. Obtain a midstream urine sample before starting antibiotics and send for urine culture and susceptibility
– Review the choice of antibiotic when the results are available
– change the antibiotic according to susceptibility results if the bacteria are resistant, using a narrow-spectrum antibiotic wherever possibleThe first choice of antibiotics for pregnant women aged 12 years and over is:
1. Nitrofurantoin
100 mg modified-release PO BD for 3 days – if eGFR >45 ml/minuteThe second-choice (no improvement in lower UTI symptoms on first-choice for at least 48 hours, or when first-choice is not suitable) are:
1. Amoxicillin
500 mg PO TDS for seven days (ONLY if culture results available and susceptible)
2. Cefalexin
500 mg BD for seven days
Alternative second-choices – consult local microbiologist, choose antibiotics based on culture and sensitivity results -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 51
Incorrect
-
Regarding ciprofloxacin, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Ciprofloxacin decreases plasma concentrations of theophylline.
Explanation:Ciprofloxacin increases plasma concentrations of theophylline. There is an increased risk of convulsions when quinolones are given with NSAIDs or theophylline. There is an increased risk of tendon damage when quinolones are given with corticosteroids. Quinolones are known to increase the QT-interval and should not be taken with concomitantly with other drugs that are known to cause QT-interval prolongation. There is an increased risk of myopathy when erythromycin or clarithromycin are taken with simvastatin or atorvastatin.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 52
Incorrect
-
Which of the following side effects is most likely caused by erythromycin:
Your Answer:
Correct Answer: QT - prolongation
Explanation:The side effects of erythromycin include abdominal pain, anaphylaxis,
cholestatic hepatitis, confusion,
diarrhoea, dyspepsia, fever, flatulence, hallucinations, hearing loss,
headache, hypertrophic pyloric stenosis, hypotension, Interstitial
nephritis, mild allergic reactions, nausea, nervous system effects,
including seizures, pain, pruritus, pseudomembranous colitis,
QT prolongation, rash, skin eruptions, tinnitus, urticaria,
ventricular arrhythmias, ventricular tachycardia, vertigo, vomiting -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 53
Incorrect
-
A patient allergic to penicillin and with marked cellulitis presents and you decide to start him on erythromycin.
Which statement about macrolide antibiotics is true?
Your Answer:
Correct Answer: They are actively concentrated within leukocytes
Explanation:Macrolide antibiotics are bacteriostatic.
They act by binding to the 50S subunit of the bacterial ribosome inhibit protein synthesis.
Macrolide antibiotics are actively concentrated within leukocytes, because of this, they are transported into the site of infection.
Macrolide antibiotics are not effective in meningitis as they do not penetrate the central nervous system well.
They are mainly against Gram-positive organisms and can be used as an alternative in patients with penicillin allergy.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 54
Incorrect
-
Which of the following antibiotics may be used for malaria prophylaxis:
Your Answer:
Correct Answer: Doxycycline
Explanation:Doxycycline may be used for malaria prophylaxis and as an adjunct to quinine in the treatment of Plasmodium falciparum malaria.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 55
Incorrect
-
Following a phone call from the microbiology consultant, you evaluate a patient who has been diagnosed with urinary sepsis. Following the results of the blood cultures, he recommends that you add gentamicin to the patient's antibiotic treatment.
Gentamicin produces its pharmacological effect by binding to which of the following?Your Answer:
Correct Answer: The 30S subunit of the bacterial ribosome
Explanation:Antibiotics with aminoglycosides, such as gentamicin, bind to the 30S subunit of the bacterial ribosome and prevent aminoacyl-tRNA from binding, preventing protein synthesis.
They also cause mRNA misreading, resulting in the production of non-functional proteins. This last mechanism is unique to aminoglycosides, and it may explain why they are bactericidal rather than bacteriostatic, as other protein synthesis inhibitors are.
Patients with myasthenia gravis should avoid aminoglycosides since they can disrupt neuromuscular transmission. They cross the placenta and are linked to poisoning of the 8th cranial nerve in the foetus, as well as permanent bilateral deafness.
It is possible that they will cause deafness, although this is not a contraindication. In individuals with renal impairment, serum aminoglycoside concentrations should be closely monitored, but this is still not considered a contraindication.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 56
Incorrect
-
Regarding macrolide antibiotics, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Macrolides are first line for treatment of whooping cough.
Explanation:A macrolide antibiotic is recommended first line for whooping cough (if onset of cough is within the previous 21 days)
Prescribe clarithromycin for infants less than 1 month of age.
Prescribe azithromycin or clarithromycin for children aged 1 month or older, and non-pregnant adults.
Prescribe erythromycin for pregnant women.
Macrolides interfere with bacterial protein synthesis and are mainly active against Gram-positive organisms. They have a similar antibacterial spectrum to penicillin and are thus a useful alternative in penicillin-allergic patients. Erythromycin is commonly associated with gastrointestinal upset. -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 57
Incorrect
-
A 7-days-old neonate is taken to the emergency department. She's pyretic, lethargic, and unresponsive, and her fontanelle has bulged. Antibiotics are started, and a lumbar puncture reveals Gram-negative rods. Which pathogen is most likely to be the cause:
Your Answer:
Correct Answer: Escherichia coli
Explanation:Among neonates, group B streptococci (GBS) are the most commonly identified causes of bacterial meningitis, implicated in roughly 50% of all cases. Escherichia coli(Gram-negative rods) accounts for another 20%. Thus, the identification and treatment of maternal genitourinary infections is an important prevention strategy.
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This question is part of the following fields:
- Infections
- Microbiology
-
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Question 58
Incorrect
-
Which of the following is NOT a notifiable disease:
Your Answer:
Correct Answer: HIV
Explanation:HIV mainly infects CD4+ T helper cells. Viral replication results in progressive T-cell depletion and impaired cell-mediated immunity with subsequent secondary opportunistic infections and increased risk of malignancy. B-cell function is also reduced as a result of lack of T-cell stimulation.
HIV is not a notifiable disease. -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 59
Incorrect
-
A 22-year-old woman is brought in by ambulance from her GP surgery with suspected meningitis. She has been given a dose of benzylpenicillin already.
What is the mechanism of action of benzylpenicillin? Select ONE answer only.Your Answer:
Correct Answer: Inhibition of cell wall synthesis
Explanation:Penicillins and the other ß-lactam antibiotics are bactericidal. They produce their antimicrobial action by preventing cross-linkage between the linear peptidoglycan polymer chains that make up the bacterial cell wall. They, therefore, inhibit cell wall synthesis.
An overview of the different mechanisms of action of the various types of antimicrobial agents is shown below:
Mechanism of action
Examples
Inhibition of cell wall synthesis
Penicillins
Cephalosporins
Vancomycin
Disruption of cell membrane function
Polymyxins
Nystatin
Amphotericin B
Inhibition of protein synthesis
Macrolides
Aminoglycosides
Tetracyclines
Chloramphenicol
Inhibition of nucleic acid synthesis
Quinolones
Trimethoprim
5-nitroimidazoles
Rifampicin
Anti-metabolic activity
Sulfonamides
Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 60
Incorrect
-
A 22-year-old man comes to the emergency department with a human bite injury to his hand received from a punch during a fight 3 hours earlier outside a bar. On closer inspection, you discover bite marks on his first and second knuckles. Which of the following is the best treatment option for this patient:
Your Answer:
Correct Answer: Oral co-amoxiclav for 7 days
Explanation:Even if there is no evidence of infection, prophylactic antibiotics should be administered for all human bite wounds that are less than 72 hours old. The first-line therapy is 7 days of co-amoxiclav. In penicillin-allergic people, metronidazole + doxycycline is an option. Streptococcus spp., Staphylococcus aureus, Haemophilus spp., Eikenella corrodens, Bacteroides spp., and other anaerobes are the most prevalent organisms found in human bites.
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This question is part of the following fields:
- Infections
- Microbiology
-
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Question 61
Incorrect
-
Regarding benzylpenicillin, which of the following statements is CORRECT:
Your Answer:
Correct Answer: If meningococcal disease is suspected, benzylpenicillin should be given before transfer to hospital.
Explanation:Benzylpenicillin (although inactivated by bacterial beta-lactamases) is effective for many streptococcal (including pneumococcal), gonococcal, and meningococcal infections and also for anthrax, diphtheria, gas gangrene, leptospirosis, and treatment of Lyme disease. If meningococcal disease (meningitis with non-blanching rash or meningococcal septicaemia) is suspected, benzylpenicillin should be given before transfer to hospital, so long as this does not delay the transfer; benzylpenicillin is no longer the drug of first choice for pneumococcal meningitis. Although benzylpenicillin is effective in the treatment of tetanus, metronidazole is preferred. Benzylpenicillin is inactivated by gastric acid and absorption from the gastrointestinal tract is poor and therefore it must be given by injection.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 62
Incorrect
-
In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic disrupts cell membrane function.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer:
Correct Answer: Nystatin
Explanation:Nystatin binds ergosterol (unique to the fungi cell membrane) and forms membrane pores that allow K+ leakage, acidification, and subsequent death of the fungus.
Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors.
Flucloxacillin inhibits the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell wall of Gram-positive bacteria.
Trimethoprim inhibits bacterial dihydrofolate reductase.
Isoniazid decreases the synthesis of mycolic acids in mycobacteria.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 63
Incorrect
-
All of the following statements are correct regarding penicillin antibiotics except:
Your Answer:
Correct Answer: Penicillins are of no use in meningitis as they are unable to penetrate into the cerebrospinal fluid.
Explanation:Penicillin penetration into the cerebrospinal fluid is generally poor. However, when the meninges are inflamed, as in meningitis, penetration of penicillin is increased. Benzylpenicillin should be given before transfer to hospital if meningococcal disease (meningitis with non-blanching rash or meningococcal septicaemia) is suspected, once this does not delay transfer.
Benzylpenicillin is no longer the drug of first choice for pneumococcal meningitis.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 64
Incorrect
-
You need to give your patient antibiotics, so you call microbiology for some advice.
Of the following antibacterial drugs, which of them is a protein synthesis inhibitor?
Your Answer:
Correct Answer: Erythromycin
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolides. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and, as a result, inhibit protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered into the infection site as a result.
Action Mechanisms- Examples:
Cell wall production is inhibited
Vancomycin
Vancomycin
CephalosporinsThe function of the cell membrane is disrupted
Nystatin
Polymyxins
Amphotericin BInhibition of protein synthesis
Chloramphenicol
Macrolides
Aminoglycosides
TetracyclinesNucleic acid synthesis inhibition
Quinolones
Trimethoprim
Rifampicin
5-nitroimidazoles
Sulphonamides
Anti-metabolic activity
Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 65
Incorrect
-
You're currently treating an infection in a patient and trying to figure out which antibiotic would be best.
Which of the following antimicrobial drugs inhibits the formation of cell walls?Your Answer:
Correct Answer: Cefuroxime
Explanation:Cefuroxime and other cephalosporin antibiotics are bactericidal ß-lactam antibiotics. They work similarly to penicillins in that they prevent cross-linking between the linear peptidoglycan polymer chains that make up the bacterial cell wall. As a result, they prevent the formation of cell walls.
The following is a summary of the various mechanisms of action of various types of antimicrobial agents:1) Inhibition of cell wall synthesis
Penicillins
Cephalosporins
Vancomycin2) Disruption of cell membrane function
Polymyxins
Nystatin
Amphotericin B3) Inhibition of protein synthesis
Macrolides
Aminoglycosides
Tetracyclines
Chloramphenicol4) Inhibition of nucleic acid synthesis
Quinolones
Trimethoprim
5-nitroimidazoles
Rifampicin5) Anti-metabolic activity
Sulphonamides
Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 66
Incorrect
-
You investigated a patient with a chest infection and want to start antibiotics right away. The patient says they she can't take cephalosporins when you ask about allergies.
Choose the 'second-generation' cephalosporin from the following choices?Your Answer:
Correct Answer: Cefuroxime
Explanation:Cephalosporins of the first generation include cephalexin, cefradine, and cefadroxil. Urinary tract infections, respiratory tract infections, otitis media, and skin and soft-tissue infections are all treated with them.
Second-generation cephalosporins include cefuroxime, cefaclor, and cefoxitin. These cephalosporins are less vulnerable to beta-lactamase inactivation than the ‘first-generation’ cephalosporins. As a result, they’re effective against germs that are resistant to other antibiotics, and they’re especially effective against Haemophilus influenzae.
Cephalosporins of the third generation include cefotaxime, ceftazidime, and ceftriaxone. They are more effective against Gram-negative bacteria than second generation’ cephalosporins. They are, however, less effective against Gram-positive bacteria such Staphylococcus aureus than second-generation cephalosporins.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 67
Incorrect
-
A 40-year-old man complains of pain and redness in his lower thigh due to an insect bite. He was diagnosed with cellulitis. Select the first-line antibiotic for cellulitis.
Your Answer:
Correct Answer: Flucloxacillin
Explanation:Cellulitis is most commonly caused by bacteria from the group Aß-hemolytic streptococcus.
Cellulitis can be caused by animal bites. For uncomplicated cellulitis, flucloxacillin is the first-line antibiotic. Because it is beta-lactamase stable, it is efficient against Staphylococcus aureus.
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This question is part of the following fields:
- Infections
- Microbiology
-
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Question 68
Incorrect
-
Which of the following statements is correct regarding gentamicin?
Your Answer:
Correct Answer: Gentamicin is ineffective against anaerobic bacteria.
Explanation:Gentamicin is the aminoglycoside of choice and is a parenterally administered, broad spectrum antibiotic typically used for moderate to severe gram negative infections. However, it is inactive against anaerobes. There is poor activity against haemolytic streptococci and pneumococci. It is usually given in conjunction with a penicillin or metronidazole (or both) when used for the blind treatment of undiagnosed serious infections. Nephrotoxicity and ototoxicity are the main toxic effects due to damage to the vestibulocochlear nerve (CN VIII).
It is contraindicated in myasthenia gravis and should be used with great care in renal disease as it may result in accumulation and a higher risk of toxic side effects.
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This question is part of the following fields:
- Infections
- Pharmacology
-
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Question 69
Incorrect
-
Aldin is a 24-year-old male patient who arrives at the emergency department diagnosed with psittacosis based on his symptoms and history of being a pigeon enthusiast. Which of the following is the causative bacteria of psittacosis?
Your Answer:
Correct Answer: Chlamydia psittaci
Explanation:Chlamydia psittaci is a microorganism that is commonly found in birds.
These bacteria can infect people and cause psittacosis. Psittacosis is an infectious disease that may cause high fever and pneumonia associated with headaches, altered mental state, and hepatosplenomegaly.
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This question is part of the following fields:
- Infections
- Microbiology
-
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Question 70
Incorrect
-
A 7-year-old presented to a GP with a history of headache, neck stiffness and photophobia. On examination, HR is 122, BP is 87/42, RR is 28, SaO 2 is 95%, temperature is 39.4 o C. There is a recent non-blanching rash on legs and arms. The GP administered a dose of antibiotics before transferring child to the Emergency Department.
Which of these is the most appropriate antibiotic to administer in this scenario from the choices available?
Your Answer:
Correct Answer: Give IM benzylpenicillin 600 mg
Explanation:Meningococcal septicaemia should be suspected in a child with a non-blanching rash especially in the presence of:
An ill-looking child
Neck stiffness
Lesions larger than 2 mm in diameter (purpura)
Capillary refill time of>3 secondsThe index child is very sick and shows signs of septic shock. In the prehospital setting, a single dose of benzylpenicillin should be given immediately. The correct dose for this childs age is IM benzylpenicillin 600 mg.
The recommended doses of benzylpenicillin according to age are:
Infants <1 year of age: IM or IV benzylpenicillin 300 mg
Children 1 to 9 years of age: IM or IV benzylpenicillin 600mg
Children and adults 10 years or older: IM or IV benzylpenicillin 1.2g -
This question is part of the following fields:
- Infections
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
