-
Question 1
Correct
-
Which of the following microbes binds strongly to CD4 antigen:
Your 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:
- Microbiology
- Principles
-
-
Question 2
Correct
-
An outbreak of acute pneumonia occurs in military recruits living in one barrack and only in those persons located near the air conditioner. Epidemiologic surveillance results in isolation of the causal organism from the patients and from the drip pans of the air conditioner. The organism is weakly Gram-negative. The most likely organism is:
Your Answer: Legionella pneumophila
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 3
Incorrect
-
Regarding control of hospital acquired infection (HAI), which of the following statements is CORRECT:
Your Answer: Disinfection is the removal of foreign material from areas or objects to a point at which they are visually free from debris.
Correct Answer: Chlorhexidine is an anti-staphylococcal agent.
Explanation:Chlorhexidine is an anti-staphylococcal agent. Cleaning is the removal of foreign material from areas or objects to a point at which they are visually free from debris. Disinfection is the reduction in the number of infectious particles. Isopropyl alcohol is not effective against C. difficile spores. Autoclaving is a method of sterilisation.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 4
Incorrect
-
The most common source of healthcare-associated bacteraemia is:
Your Answer: Fomites
Correct Answer: Intravenous cannula
Explanation:Healthcare-associated bacteraemia is most commonly caused by intravenous access. Any intravenous device that is left in place for a long time increases the risk of infection. It allows bacteria like Staphylococcus aureus and Staphylococcus epidermidis to enter the body.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 5
Correct
-
Which of the following microbes adheres to the genital mucosa using fimbriae:
Your Answer: Neisseria gonorrhoeae
Explanation:Infection of the genital mucosa by Neisseria gonorrhoeae involves attachment to and invasion of epithelial cells. Initial adherence of gonococci to columnar epithelial cells is mediated by type IV pili assembled from pilin subunit PilE proteins and pilus tip-associated PilC proteins, it then invades the epithelial layer, triggering a local acute inflammatory response.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 6
Correct
-
Infection with Campylobacter jejuni is one of the most common risk factors for which of the following conditions?
Your Answer: Guillain-Barre syndrome
Explanation:One of the most common risk factors for GBS is infection with Campylobacter jejuni, which causes diarrhoea. Guillain-Barré syndrome (GBS) is a rare autoimmune disorder in which the body’s immune system attacks the nerves, resulting in muscle weakness and paralysis. Infection with Streptococcus pyogenes can cause acute glomerulonephritis and rheumatic fever. Haemolytic uraemic syndrome is commonly linked to E. coli infection. Following measles infection, subacute sclerosing panencephalitis develops.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 7
Correct
-
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: 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 AeruginosaStaphylococcus aureus, including methicillin-susceptible S aureus (MSSA) and methicillin-resistant S aureus (MRSA)Klebsiella pneumoniaeEscherichia coli
-
This question is part of the following fields:
- Infections
- Microbiology
-
-
Question 8
Correct
-
You are treating a patient with a Clostridium difficile infection. His condition was found to be antibiotic-associated. Which of the following pieces of advice on preventing the spread of this disease should you give this patient?
Your Answer: Washing hands with soap and water
Explanation:Clostridium difficile (C. diff) can cause colitis, or inflammation of the colon. To prevent its spread, one should practice good hand hygiene, regularly clean areas of the home that may become contaminated with C. difficile, practice good hand hygiene, and clean surfaces, spills, and accidents.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 9
Correct
-
Red cell protein expression is induced by which of the following pathogens:
Your Answer: Plasmodium falciparum
Explanation:Plasmodium falciparum induces the expression of red cell protein, making cerebral malaria more severe. Bacteria may invade a host passively through micro traumata or macro traumata in the skin or mucosa. On the other hand, bacteria that invadethrough intact mucosa first, adhere to this anatomical barrier, then activelybreach it.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 10
Correct
-
Bordetella pertussis is spread via which of the following routes:
Your Answer: Respiratory droplet route
Explanation:Bordetella pertussis is a Gram negative coccobacillus that causes whooping cough. B. pertussis is spread via the respiratory droplet route and expresses fimbriae that aid their adhesion to the ciliated epithelium of the upper respiratory tract, and produce a number of exotoxins, causing the characteristic thickened bronchial secretions, paralysis of cilia and lymphocytosis.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 11
Incorrect
-
Regarding tapeworm, which of the following statements is CORRECT:
Your Answer: Tapeworm migrate from the intestine at night to lay eggs on the perianal skin.
Correct Answer: Diagnosis is by direct visualisation of characteristic eggs in the stool.
Explanation:Diagnosis of tapeworm is by direct visualisation of characteristic eggs in stool. Humans may be infected by pork or beef tapeworm. Treatment is with praziquantel or niclosamide. Specialist advice should be sought for the management of neurocysticercosis.Iron-deficiency anaemia is typically seen in hookworm infection. Threadworms migrate from the intestine at night to lay eggs on the perianal skin. Mebendazole is first line treatment for threadworms.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 12
Correct
-
Question 13
Correct
-
The percentage of patients with hepatitis B that develop chronic infection is about:
Your Answer: 10%
Explanation:With hepatitis B, about 90% of people will develop lifelong immunity after clearing the infection. Chronic hepatitis develops in about 10% of patients and this may be complicated by cirrhosis or hepatocellular carcinoma. There is a very high risk of chronic infection and hepatocellular carcinoma when there is congenital infection. The risk of this in healthy adults is only about 5%.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 14
Incorrect
-
A 40-year-old woman presents with a fever and headache upon returning from an overseas business trip. Upon further investigation, a diagnosis of Plasmodium falciparum malaria was made.All of the following statements is considered true regarding Plasmodium falciparum malaria, except:
Your Answer: Sporozoites invade hepatocytes
Correct Answer: It is commonly the result of travel in the Indian subcontinent
Explanation:The mean incubation period for P. falciparum is 12 days.WHO World Malaria Report 2019 states that an estimated 228 million cases of malaria occurred worldwide in 2018, and reports steadily decreasing the number of cases since 2010. In 2018, nineteen sub-Saharan African countries and India carried approximately 85% of the global malaria burden. The most prevalent and pathogenic malaria parasite, most commonly associated with severe illness and death, especially in the WHO African region, accounting for 99.7% malaria cases, is P. falciparum.The vector for Plasmodium spp. is a female Anopheles mosquito that inoculates sporozoites contained in her salivary glands into the puncture wound when feeding. Sporozoites enter peripheral bloodstream and are uptake by hepatocytes, where they undergo an asexual pre-erythrocytic liver-stage as liver schizonts lasting up to 2 weeks before the onset of the blood stage.Intravenous or intramuscular artesunate is the first-line treatment in all patients worldwide and should be used for at least 24 hours and until the oral medication is tolerated.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 15
Incorrect
-
The monospot test for infectious mononucleosis uses which of the following types of red blood cell?
Your Answer: Ox red blood cells
Correct Answer: Horse red blood cells
Explanation:Infectious mononucleosis can be diagnosed using specific EBV antibodies and a variety if unrelated non-EBV heterophile antibodies. These antibodies can be detected by two main screening tests:The monospot test uses horse red blood cells. It agglutinates in the presence of heterophile antibodies.Sheep red blood cells is used in Paul-Bunnell test. The blood agglutinates in the presence of heterophile antibodies.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 16
Correct
-
Clostridium difficile primarily causes which of the following infectious diseases:
Your Answer: Pseudomembranous colitis
Explanation:Clostridium difficile causes pseudomembranous colitis, an acute inflammatory diarrhoeal disease and an important cause of morbidity and mortality in hospitals. Gas gangrene is primarily caused by Clostridium perfringens. Tetanus is caused by Clostridium tetani. Toxic shock syndrome may be caused by Staphylococcus aureus or Streptococcus pyogenes. Necrotising fasciitis is most commonly caused by Streptococcus pyogenes but has a multitude of causes.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 17
Incorrect
-
Regarding Escherichia coli, which of the following statements is INCORRECT:
Your Answer: It is a common cause of neonatal meningitis.
Correct Answer: It is a predominant member of the normal flora of the skin.
Explanation:Escherichia coli is a Gram-negative bacilli that is an important member of the intestinal flora. It is the most common cause of UTI in adults (about 70 – 95% of cases), followed by Staphylococcus saprophyticus (about 5 – 10% of cases), and an important cause of neonatal meningitis. E. coli O157 strain is implicated in the development of dysentery associated with haemolytic uraemic syndrome characterised by haemolytic anaemia, thrombocytopenia and acute renal failure.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 18
Incorrect
-
A 6 year old boy is brought into the ED by his mom with a rash that is associated with Koplik's spots and a diagnosis of measles is made. What advice should be given about returning to school?
Your Answer: 7 days after the rash has gone
Correct Answer: 4 days from the onset of the rash
Explanation:Prevention of spread of measles is extremely important and infected patients should be isolated. The infectious stage is from 3 days before the rash emerges and patients are advised to stay away from school/nursery/work for 4 days from onset of the rash.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 19
Correct
-
How is measles primarily transmitted:
Your Answer: Respiratory droplet route
Explanation:Measles belongs to the paramyxoviridae group of viruses. The incubation period is 7-18 days (average 10) and it is spread by airborne or droplet transmission. The classical presentation is of a high fever with coryzal symptoms and photophobia with conjunctivitis often being present. The rash that is associated is a widespread erythematous maculopapular rash. Koplik spots are pathognomonic for measles, and are the presence of white lesions on the buccal mucosa.Differential diagnoses would include:RubellaRoseola infantum (exanthem subitom)Scarlet feverKawasaki diseaseErythema infectiosum (5thdisease)EnterovirusInfectious mononucleosisDiagnosis can be confirmed by the following means:Salivary swab for measles specific IgMSerum sample for measles specific IgMSalivary swab for RNA detectionPossible complications include:Otitis mediaFebrile convulsionsPneumoniaBronchiectasisDiarrhoeaMeningitisEncephalitisImmunosuppressionSubacute sclerosing panencephalitisDeath
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 20
Correct
-
Regarding shingles, which of the following statements is CORRECT:
Your Answer: You can catch chickenpox from a patient with shingles.
Explanation:After primary infection, VZV remains latent in sensory ganglia and in about 20% of patients will reactivate resulting in shingles, a painful vesicular rash in the related dermatome. Shingles usually affects older people and the immunocompromised. Shingles lesions are infectious to non-immune individuals who are at risk of developing chickenpox. Shingles can not be contracted directly from chickenpox, or from other cases of shingles. Shingles is treated with systemic antiviral treatment to reduce the severity and duration of pain, reduce complications, and reduce viral shedding.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 21
Correct
-
A patient presents with a fever, headache and neck stiffness. A CSF sample of someone with meningococcal meningitis typically shows:
Your Answer: All of the above
Explanation:CSF analysis typically shows: cloudy turbid appearanceraised WCC – predominantly neutrophilshigh proteinlow glucose (typically < 40% of serum glucose)Gram-negative diplococci seen under microscopy
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 22
Incorrect
-
Anatomical barriers to infection include all of the following EXCEPT:
Your Answer: Commensal flora in the genitourinary tract
Correct Answer: Mucociliary escalator in the gastrointestinal tract
Explanation:Anatomical barriers to infection include:tight junctions between cells of the skin and mucosal membranesthe flushing action of tears, saliva and urinethe mucociliary escalator in the respiratory tract (together with the actions of coughing and sneezing)the acidic pH of gastric and vaginal secretionsthe acidic pH of the skin (maintained by lactic acid and fatty acids in sebum)enzymes such as lysozyme found in saliva, sweat and tearspepsin present in the stomachbiological commensal flora formed on the skin and the respiratory, gastrointestinal and genitourinary tracts which protect the host by competing with pathogenic bacteria for nutrients and attachment sites and by producing antibacterial substances
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 23
Correct
-
About what percentage of patients with hepatitis A develop chronic infection:
Your Answer: None
Explanation:Chronic hepatitis and carrier state does not occur in hepatitis A infection and complete immunity is attained after infection.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 24
Correct
-
Which of the following best describes the typical rash of measles:
Your Answer: The typical rash of measles is maculopapular, starting behind the ears and spreading downwards to the trunk.
Explanation:A prodromal 2 – 4 day coryzal illness (fever, cough, conjunctivitis, irritability) normally occurs associated with Koplik’s spots (small white papules found on the buccal mucosa near the first premolars), before a morbilliform maculopapular rash appears, first behind the ears and then spreading downwards to whole body.The rash peels off or fades about about 7 – 10 days. The chickenpox rash is characterised by a maculopapular rash progressing to vesicles and then crusting over. Scarlet fever is characterised by a sandpaper like rash associated with a strawberry tongue.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 25
Incorrect
-
Which of the following microbes attaches to host cells by its haemagglutinin antigen:
Your Answer: Haemophilus influenzae
Correct Answer: Influenza virus
Explanation:Hemagglutinin (HA) or Haemagglutinin (BE) is an antigenic glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to the cell that is being infected. The name hemagglutinin comes from the protein’s ability to cause red blood cells (erythrocytes) to clump together (agglutinate) in vitro.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 26
Incorrect
-
Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: It produces exotoxins A and B and binary toxin.
Correct Answer: Infection is predominantly derived from animal faeces and soil.
Explanation:Clostridium tetaniis a Gram positive, rod shaped, obligate anaerobic bacterium.The incubation period is quoted as anywhere between 4-21 days and can occur after several months but symptoms usually occur within the first 7 days after exposure.Approximately 80% of patients develop generalised tetanus. The commonest presenting feature of generalised tetanus is trismus (lockjaw), occurring in approximately 75% of affected individuals. Other clinical features include:Facial spasms (risus sardonicus)Opisthotonus (characteristic body shape during spasms)Neck stiffnessDysphagiaCalf and pectoral muscle rigidityFeverHypertensionTachycardiaSpasms can occur frequently and last for several minutes, they can continue to occur for up to 4 weeks. Current mortality rates are between 10 and 15%.Tetanic spasms are caused by the exotoxin tetanospasmin. The effects of tetanolysin are not fully understood but it is not believed to have clinical significance.Localised tetanus is a rare form of the disease, occurring in around 1% of affected individuals. Patients have persistent contraction of muscles in the same anatomic area as the injury. It may precede generalised tetanus.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 27
Incorrect
-
Which of the following is NOT a typical complication associated with mumps:
Your Answer: Pancreatitis
Correct Answer: Subacute sclerosing panencephalitis
Explanation:Complications of mumps include meningitis, post meningitis deafness, encephalitis, pancreatitis, orchitis and oophoritis. Subacute sclerosing panencephalitis is a complication typically associated with measles infection.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 28
Correct
-
A 17-year-old patient with a headache, fever, and a non-blanching rash is brought to the emergency room. Meningococcal infection is confirmed by a lumbar puncture. Neisseria meningitidis uses one of the following immune evasion mechanisms:
Your Answer: Secretes IgA protease
Explanation:Meningococci have 3 important virulence factors, as follows:Polysaccharide capsule – Individuals with immunity against meningococcal infections have bactericidal antibodies against cell wall antigens and capsular polysaccharides; a deficiency of circulating anti meningococcal antibodies is associated with the disease.Lipo-oligosaccharide endotoxin (LOS)Immunoglobulin A1 (IgA1)
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 29
Incorrect
-
Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: Tetanolysin is predominantly responsible for its neurotoxic effects.
Correct Answer: Germination and outgrowth of clostridial spores depends on anaerobic conditions.
Explanation:Clostridium tetani is found in normal human intestinal flora, although infection is predominantly exogenous. Tetanospasmin, an exotoxin produced by C. tetani is responsible for the neurotoxic effects of tetanus, largely by preventing the release of the inhibitory neurotransmitter GABA, resulting in prolonged excitation. Clostridium tetani is an obligate anaerobe, with an incubation period of about 3 – 21 days (average 10 days).
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 30
Correct
-
You received a patient with a 2-day history of diarrhoea and vomiting. Later, after examination, the patient was found to have progressive symmetric descending flaccid paralysis, initial development of blurred vision, dysphagia, and weakness of the upper limbs. The patient is apyrexial and his observations are all normal. Which of the following pathogens is responsible for the said symptoms?
Your Answer: Clostridium botulinum
Explanation:A botulism infection results in neuroparalysis caused by the neurotoxin generated by Clostridium botulinum. Food-borne botulism symptoms often appear 12-36 hours after ingestion of the toxin-containing food and may include nausea, vomiting, stomach discomfort, and diarrhoea at first. The most common neurological pattern is an acute onset of bilateral cranial neuropathies with symmetric declining weakening. Other distinguishing characteristics include the absence of fever, the absence of cognitive abnormalities, the presence of a normal heart rate and blood pressure, and the absence of sensory defects.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 31
Correct
-
Which patient group are most commonly associated with infection with Klebsiella spp:
Your Answer: Hospitalised patients
Explanation:Klebsiella spp. are facultatively anaerobic Gram-negative rods, found in the normal intestinal and respiratory flora. These organisms are usually opportunistic pathogens that cause nosocomial infections, most commonly pneumonia and UTI.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 32
Correct
-
What is the primary route of transmission of Neisseria Gonorrhoeae?
Your Answer: Sexually transmitted
Explanation:Neisseria gonorrhoeae is primarily spread by sexual contact or through transmission during childbirth. It causes gonorrhoea which is a purulent infection of the mucous membrane surfaces.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 33
Incorrect
-
You review a 37-year-old man with a history of intravenous drug abuse who admits to sharing needles in the past. He has a flu-like illness and a rash. Concerned he may be experiencing an HIV seroconversion illness, you order a test.Which of these tests is most reliably used to diagnose HIV at this stage?
Your Answer: ELISA antibody test
Correct Answer: p24 antigen test
Explanation:Serum concentrations of the p24 antigen are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection. P24 is the viral protein that makes up most of the core of the HIV.ELISA and other antibody tests, though a very sensitive way of detecting the presence of HIV, cannot be used in the early stages of the disease. This is because of the window period of 6-12 weeks before antibodies are produced. These tests will be negative during a seroconversion illness.The ‘rapid HIV test’ is an HIV antibody test. It will also be negative during the ‘window period’ since it takes time for antibodies to be produced. It is called the ‘rapid test’ as it can detect antibodies in blood or saliva much quicker than the other antibody tests and results are often back within 20 minutes.CD4 and CD8 counts are usually normal in the early stages of the HIV infection and cannot be used in this case.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 34
Correct
-
Regarding dermatophytes, which of the following statement is CORRECT:
Your Answer: Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings.
Explanation:Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings depending on the site of infection. The lesions of ringworm typically have a dark outer ring with a pale centre. Tinea capitis is ringworm affecting the head and scalp. Spread is via direct skin contact. Treatment is usually topical, oral antifungals are reserved for refractory infection.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 35
Correct
-
Regarding the varicella zoster virus, which of the following statements is CORRECT:
Your Answer: Contracting chickenpox infection while pregnant is associated with a higher risk of developing varicella pneumonitis.
Explanation:Chickenpox infection in neonates, adults/adolescents and pregnant women is associated with more severe disease. Varicella zoster pneumonitis typically occurs in pregnant women or immunocompromised individuals and is associated with a high mortality. A live attenuated-virus vaccine is available and recommended for non-immune healthcare workers but is not part of the routine childhood immunisation schedule. Antiviral treatment is not typically recommended in childhood chickenpox but is indicated for shingles.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 36
Correct
-
Question 37
Incorrect
-
Which of the following is NOT typically present in the nasopharyngeal flora:
Your Answer: Neisseria spp.
Correct Answer: Bacteroides spp.
Explanation:Bacteroides spp. are typically found in the normal flora of the lower gastrointestinal tract. Species commonly found in the flora of the nasopharynx include: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Corynebacterium spp., Moraxella spp. and Candida spp.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 38
Correct
-
Which of the following problems is associated with Helicobacter pylori infection?
Your Answer: Gastric malignancy
Explanation:Helicobacter pylori is a ubiquitous organism that is present in about 50% of the global population. Chronic infection with H pylori causes atrophic and even metaplastic changes in the stomach, and it has a known association with peptic ulcer disease. The most common route of H pylori infection is either oral-to-oral or faecal-to-oral contact.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 39
Incorrect
-
A 22 year old student has recently returned from travelling around Kenya and presents to ED with a headache and persistent fever. Malaria is being considered as a potential diagnosis. Which of the following strains of malaria is most likely:
Your Answer: Plasmodium vivax
Correct Answer: Plasmodium falciparum
Explanation:Malaria is an infectious disease transmitted by female of theAnophelesgenus of mosquito. It is a parasitic infection caused by the genusPlasmodium. Five species are recognized as causing disease in humans;Plasmodium falciparum,Plasmodium ovale,Plasmodium vivax,Plasmodium malariaeandPlasmodium knowlesi.The classic symptom of malaria is the malarial paroxysm, a cyclical occurrence of a cold phase, where the patient experiences intense chills, a hot stage, where the patient feels extremely hot and finally a sweating stage, where the fever declines and the patient sweats profusely. On examination the patient may show signs of anaemia, jaundice and have hepatosplenomegaly without evidence of lymphadenopathy.Plasmodium falciparum is the most serious form and is responsible for most deaths. Severe or complicated malaria is suggested by the presence of impaired consciousness, seizures, hypoglycaemia, anaemia, renal impairment, respiratory distress and spontaneous bleeding.Plasmodium falciparum is the most likely type in this case in view of the presentation.Haemoglobinuria and renal failure following treatment is suggestive of blackwater fever, which is caused byPlasmodium falciparum. An autoimmune reaction between the parasite and quinine causes haemolysis, haemoglobinuria, jaundice and renal failure. This can be fatal.The benign malarias: P.vivax, P. malariae and P.ovale are usually treated with chloroquine. A course of primaquine is also required in P.vivax and P.ovale infection. Artesunate is the drug treatment of choice for Plasmodium falciparum malaria. Quinine can still be used where artesunate is not available. Often combination therapy with drugs such as doxycycline or fansidar is also required.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 40
Correct
-
Regarding Legionella species which of the following statements is CORRECT:
Your Answer: They are Gram-negative organisms.
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 41
Correct
-
A 70-year-old man has severe diarrhoea one week after taking co-amoxiclav for a chest infection. The diarrhoea is yellow in colour and smell is offensive.What is the SINGLE MOST likely causative organism?
Your Answer: Clostridium difficile
Explanation:Clostridium difficile, a Gram-positive, anaerobic, spore forming bacteria is present in the gut of approximately 3% of healthy adults (2012 UK HPA estimates). Following use of broad spectrum antibiotics, which alter normal gut flora, Clostridium difficile associated diarrhoea (CDAD) occurs.About 80% of Clostridium difficile infections are seen in people over the age of 65 and its main clinical features are:Abdominal cramps, severe bloody and/or watery diarrhoea, offensive smelling diarrhoea, and fever.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 42
Correct
-
An elderly man with chronic heart and lung disease develops Legionnaires' Disease. By what route was the infection most likely to have been acquired:
Your Answer: Inhalation of aerosolised contaminated water
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 43
Incorrect
-
A 59-year-old man is complaining of pain in his perineal area, a recent onset of urinary frequency and urgency, fever, chills, and muscle aches. He has a long history of nocturia and terminal dribbling. On rectal examination you find an exquisitely tender prostate.Which of these antibacterial agents would be most appropriate in this case?
Your Answer: Nitrofurantoin for 14 days
Correct Answer: Ciprofloxacin for 14 days
Explanation:An acute focal or diffuse suppurative inflammation of the prostate gland is called acute bacterial prostatitis.According to the National Institute for Health and Care Excellence (NICE), acute prostatitis should be suspected in a man presenting with:A feverish illness of sudden onset which may be associated with rigors, arthralgia, or myalgia; Irritative urinary voiding symptoms; acute urinary retention; perineal or suprapubic pain and an exquisitely tender prostate on rectal examination.Treatment of acute prostatitis as recommended by NICE and the BNFare:Ciprofloxacin or ofloxacin for 14 daysAlternatively, trimethoprim can be used. Duration of treatment is still 14 days
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 44
Incorrect
-
A 54-year-old man returns from a recently holiday on a cruise ship with a dry cough and a fever. Today he has also had several episodes of diarrhoea and has developed bilateral pleuritic chest pain. He states that he is short of breath, most notably on exertion. He had been prescribed amoxicillin by the cruise ship doctor a few days earlier but has not seen any improvement.Which of the following is the most likely causative organism? Select ONE answer only.
Your Answer: Klebsiella pneumoniae
Correct Answer: Legionella pneumophila
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 45
Correct
-
Which of the following serology results is consistent with chronic hepatitis B infection:
Your Answer: HBsAg positive and anti-HBc IgG positive
Explanation:Disease state vs SerologyAcute hepatitis: BHBsAg, HBeAg, anti-HBc IgMChronic hepatitis B (low infectivity): HBsAg (>6/12), anti-HBe, anti-HBc IgGChronic hepatitis B (high infectivity): HBsAg (>6/12), HBeAg, anti-HBc IgGCleared infection: Anti-HBs, anti-HBe, anti-HBc IgGVaccinated: Anti-HBs
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 46
Correct
-
A patient presents with a gastrointestinal infection. Which of the following microbes attaches to gut mucosa via a specialised sucking disc:
Your Answer: Giardia lamblia
Explanation:Giardia lambliainfection occurs through the ingestion of dormant microbial cysts in contaminated water, food or via faceo-oral transmission via poor hygiene.Following ingestion of the cysts, the trophozoite emerges to an active state of feeding and motility. After the feeding stage they undergo asexual replication through longitudinal binary fission.They attach to the intestinal wall via a specialised sucking disc. The mechanism for diarrhoea in giardiasis remains unknown but could possibly be due to direct cytotoxicity.Giardial trophozoites and cysts pass through the digestive system in the faeces and are excreted. While the trophozoites may be found in the faeces, only the cysts are adapted for long-term survival outside the host.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 47
Incorrect
-
You suspected typhoid disease in a patient who had recently returned from South America and presented to the emergency department with fever, constipation, and a rose spot rash. Which of the following antibiotics will be administered to this patient?
Your Answer: Clarithromycin
Correct Answer: Cefotaxime
Explanation:Typhoid fever, often known as enteric fever, is a potentially fatal multi-systemic sickness caused predominantly by Salmonella enterica serotype typhi and, to a lesser extent, paratyphi A, B, and C. Cefotaxime is the first-line treatment for typhoid fever (or ceftriaxone). In cases of mild or moderate sickness caused by multiresistant pathogens, azithromycin is an option. If the bacterium is sensitive, ciprofloxacin is an option.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 48
Correct
-
What is the primary route of transmission of Norovirus?
Your Answer: Oral-faecal route
Explanation:Norovirus is spread primarily by faecal-oral contact, but it can also be spread through contact with an infected person, ingestion of contaminated food or water, or contact with contaminated surfaces or items.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 49
Incorrect
-
A blood test of a 7-year-old child with a 6-day history of bloody diarrhoea reveals a low platelet count, anaemia, and impaired kidney function. What bacteria is suspected of causing such a condition?
Your Answer: Campylobacter jejuni
Correct Answer: Escherichia coli
Explanation:Escherichia coli produces shiga toxin that causes diarrhoea, hemorrhagic colitis, and haemolytic uremic syndrome. Haemolytic uremic syndrome is characterized by anaemia, thrombocytopenia, and acute renal failure. Transmission of E. coli is possible after consuming contaminated, undercooked drinks and foods. E. coli enters the body via the faecal-oral pathway.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 50
Incorrect
-
Regarding hepatitis A, which of the following statements is CORRECT:
Your Answer: Transmission is by the parenteral route.
Correct Answer: Anti-HAV IgM antibodies are diagnostic.
Explanation:Anti-HAV IgM antibodies are diagnostic. Disease in children is more commonly asymptomatic, risk of symptomatic disease increases with age. Transmission is by the faecal-oral route. Faecal shedding has been demonstrated for 2 – 3 weeks before and about a week after, the onset of jaundice. Infection confers lifelong immunity.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
SESSION STATS - PERFORMANCE PER SPECIALTY
