-
Question 1
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 2
Correct
-
A 30-year-old male farmer presents to the Emergency Department due to a wound on his right forearm sustained two days ago while working on the farm. He cleaned the wound under a tap, but there was still some dirt and debris on examination.
Past medical history reveals that he never received a tetanus vaccine.
After cleaning the wound and prescribing antibiotics, which ONE of the following actions should be taken to manage his tetanus risk?Your Answer: Tetanus vaccination and 500 IU tetanus immunoglobulin
Explanation:If a patient presents with one of the following types of wounds, they are at risk of contracting tetanus and should be vaccinated immediately:
1) Contaminated puncture-type wounds from gardening and farming (as they may contain tetanus spores)
2) Wounds containing foreign bodies
3) Open (compound) fractures
4) Wounds or burns with sepsis
5) Animal bites and scratches (animal saliva does not contain tetanus spores unless the animal was routing in soil or lives in an agriculture setting)Extremely high-risk tetanus-prone wounds are any of the above wounds with one of the following:
1) Any wound contaminated by materials containing tetanus spores, e.g., soil, manure
2) Burns or wounds with extensive devitalised tissue
3) Wounds or burns with surgical intervention delayed for more than six hours even if the initial injury was not heavily contaminatedThe CDC recommends that adults who have never been vaccinated for tetanus receive a quick shot of the tetanus vaccine along with a booster dose ten years later. A tetanus-prone wound in an unvaccinated individual should also receive a high dose of tetanus immunoglobulin. The injected antibodies will prevent tetanus infection as the patient does not have any pre-existing antibodies against the disease.
In this case, the patient has a high risk, contaminated wound. He should receive a high dose of tetanus immunoglobulin along with the tetanus vaccine. (The preventative dose of tetanus immunoglobulin is 250 IU in most cases unless over 24 hours have passed since the injury or the wound is heavily contaminated, then 500 IU should be given.) His physician also needs to be contacted to arrange the remainder of the course as indicated in this case.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 3
Correct
-
You are planning on starting antibiotic therapy for a patient with a diagnosis of gonorrhoea.
Which of these is the MOST appropriate antibiotic combination?Your Answer: Ceftriaxone and azithromycin
Explanation:Currently, ceftriaxone in combination with azithromycin or doxycycline is the combination of antibiotics used in the treatment of gonorrhoea.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 4
Correct
-
Regarding gas gangrene, which of the following statements is CORRECT:
Your Answer: Infection is characterised by rapidly spreading tissue myonecrosis with crepitus.
Explanation:Gas gangrene usually occurs within 3 days of injury, and is characterised by pain, rapidly spreading oedema, myositis, necrosis, palpable crepitus and systemic toxicity. Diagnosis is clinical and laboratory confirmation should not delay urgent surgical intervention. Hyperbaric oxygen therapy can be considered in addition to surgery and antibiotic therapy, to stop toxin production and inhibit bacteria from replicating and spreading (as Clostridium spp. are obligate anaerobes).
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 5
Correct
-
A 50-year-old man from Russia presents with a history of cough with blood-stained sputum, fever, night sweats, and weight loss. Suspecting tuberculosis, you begin investigations.
All the following statements regarding tuberculosis (TB) are true EXCEPT?Your Answer: Corticosteroid use is not a risk factor for developing TB
Explanation:Immunosuppressants like corticosteroids may be an important risk factor for developing tuberculosis.
All of the other statements are true.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 6
Correct
-
Regarding hepatitis B, which of the following statements is CORRECT:
Your Answer: Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months.
Explanation:Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months. Hepatitis B has a long incubation period of about 2 – 6 months. Hepatitis B vaccine has recently been introduced to the routine childhood immunisation schedule – given at 2, 3 and 4 months. It is also given to babies born to hepatitis B infected mothers at birth, four weeks and 12 months old. Treatment of acute hepatitis is supportive. Treatment with antivirals should be considered in chronic infection as responders have a reduced risk of liver damage and liver cancer in the long term.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 7
Correct
-
Which of the following is diagnostic for acute hepatitis B infection:
Your Answer: anti-HBc IgM
Explanation:Anti-HBc IgM antibodies are diagnostic for acute hepatitis B infection. Anti-HBc IgG antibodies indicate previous exposure, either chronic state or cleared infection. HBsAg is also positive in acute infection but is not diagnostic as this remains positive in chronic infection.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 8
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 9
Correct
-
Herpes simplex encephalitis has a predilection for which of the following sites:
Your 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.
-
This question is part of the following fields:
- Infections
- Microbiology
-
-
Question 10
Incorrect
-
A 20-year-old male patient lives in a travelling community and has never received any vaccinations. He presents to you with fever.
Which of these statements concerning indications and contraindications for vaccination is FALSE?
Your Answer: Live vaccines are contraindicated in pregnancy
Correct Answer: Premature infants should have the their immunisation schedule adjusted for gestational age
Explanation:All vaccines are contraindicated in individuals with:
A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.
A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinLive attenuated vaccines are contraindicated in pregnancy except in cases where risk of infection is more than the risks of vaccination.
During times of acute febrile illness, vaccination should be avoided.
12 weeks should elapse after a dose of human immunoglobulin before a live vaccine is administered.
The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should NOT be implemented.
-
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 11
Correct
-
A 32-year old male patient has been diagnosed with meningococcal meningitis and was given appropriate treatments. Because he is a family man, he fears that he might transmit the infection to the rest of his family members.
The causative agent of meningococcal meningitis is spread via what mode of transmission?Your Answer: Respiratory droplet route
Explanation:N. meningitidis, the causative agent of meningococcal meningitis, is considered both a commensal and a pathogen. It can be found in the surfaces of mucous membranes such as the nasopharynx and oropharynx. With this, it can be transmitted from a carrier to a new host via respiratory droplet secretions.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 12
Incorrect
-
A 32-year-old woman presents with abdominal pain and bloody diarrhoea that has been going on for 3 days.
Among the following microorganisms, which is considered to be a cause of infectious bloody diarrhoea?Your Answer: Giardia lamblia
Correct Answer: Entamoeba histolytica
Explanation:The following are organisms that are capable of producing acute, bloody diarrhoea:
– Campylobacter jejuni
– Escherichia coli O157:H7
– Salmonella species
– Shigella species
– Yersinia species
– Entamoeba histolyticaOther E. coli strains, Giardia, Vibrio, and other parasites are associated with watery, but not bloody, diarrhoea.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 13
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 14
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 days
Cough (usually non-productive and occurs in approximately 90%)
Pleuritic chest pain
Haemoptysis
Headache
Nausea, vomiting and diarrhoea
Anorexia
Legionella 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 15
Correct
-
All of the following statements regarding Helicobacter pylori is considered true, except:
Your Answer: Serum antibody levels should be used to check for successful eradication
Explanation:Helicobacter pylori is a curved, non-spore forming, Gram-negative bacteria that is primarily linked to gastric infections. Once acquired, it colonizes the stomach for a long time and can cause a low-grade inflammatory process, producing a chronic superficial gastritis.
H. pylori can be recovered from gastric biopsy materials. Samples must be transported quickly to the laboratory.
Helicobacter infections usually are identified by nonculture methods. H. pylori can be presumptively identified in a gastric biopsy specimen by testing for the presence of a rapid urease reaction.Serologic testing is an important screening method for the diagnosis of H. pylori infection. It can also be diagnosed by faecal antigen detection, microscopic examination of stained gastric tissue, and DNA amplification tests.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 16
Correct
-
A patient with a central line in situ for the past 10 days now has erythema surrounding the catheter insertion site and shows signs of sepsis. You suspect line sepsis.
Which of these antibacterial agents would be most appropriate to prescribe for this patient?Your Answer: Vancomycin
Explanation:The current recommendation by NICE and the BNF is to use vancomycin as first-line in treatment of septicaemia related to vascular catheter. A broad-spectrum antipseudomonal beta-lactam antibiotic should be added to vancomycin if a Gram-negative sepsis is suspected especially in an immunocompromised patient.
In any patient that has had a central venous catheter in situ for a period longer than a week, it should be suspected as the source of sepsis.
The features suggesting the vascular catheter as the source of infection include:
Presence of the catheter before onset of fever.
The absence of another identifiable source of infection.
Presence of inflammation or purulent material at the insertion site or along the tunnel.
An immunocompetent patient without any underlying disease developing bacteraemia (or fungaemia). -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 17
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 18
Incorrect
-
Which of the following nerves is responsible for the symptoms of a patient with history of recurrent herpes simplex outbreaks on his face and presents with ophthalmic herpes zoster and a painful vesicle on the tip of his nose?
Your Answer: Infraorbital nerve
Correct Answer: Nasociliary nerve
Explanation:Hutchinson sign relates to involvement of the tip of the nose from facial herpes zoster. It implies involvement of the external nasal branch of the nasociliary nerve which is a branch of the ophthalmic division of the trigeminal nerve.
The nasociliary branch of the trigeminal nerve innervates the apex and lateral aspect of the nose, as well as the cornea. Therefore, lesions on the side or tip of the nose should raise suspicion of ocular involvement.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 19
Correct
-
An 18-year-old student presents with a 1-week history of sore throat, low grade fever, and malaise. Upon history taking, she noted that she had a fine rash over her body a week ago that quickly fades. Further examination and observation was done and the presence of mild splenomegaly was noted. Her test shows positive for heterophile antibody test, suspecting a diagnosis of infectious mononucleosis.
Which of the following characteristics is mostly associated with the diagnosis of infectious mononucleosis?Your Answer: Atypical lymphocytes
Explanation:Epstein-Barr virus causes infectious mononucleosis which is a clinical entity characterized by sore throat, cervical lymph node enlargement, fatigue and fever.
It is accompanied by atypical large peripheral blood lymphocytes. These atypical lymphocytes, also known as Downey cells, are actually activated CD8 T lymphocytes, most of which are responding to EBV-infected cells.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 20
Correct
-
A 29-year-old male presents with a 3-day history of bloody diarrhoea and abdominal pain.
All the following are causes of infectious bloody diarrhoea EXCEPT?
Your Answer: Enterotoxigenic Escherichia coli
Explanation:Infective causes of bloody diarrhoea include:
Salmonella spp
Campylobacter spp
Schistosomiasis
Entamoeba histolytica (Amoebiasis )
Shigella spp
Clostridium difficile
Yersinia spp
Enteroinvasive Escherichia coliEnterotoxigenic Escherichia coli is non-invasive and does not cause inflammation of the gut and bloody diarrhoea. It presents with copious watery diarrhoea and usually are not associated with abdominal cramping.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 21
Correct
-
In a 7-year-old child with chickenpox, which of the following would you advise the mother NOT to do?
Your Answer: Give ibuprofen for the fever
Explanation:Chickenpox (varicella zoster) is a highly contagious airborne disease and has an incubation period of between 7-21 days. It often has a prodromal phase when there is a fever, aches and headaches, dry cough, and sore throat before onset of rash.
Some recognized complications of chickenpox are:
Orchitis
Hepatitis
Pneumonia
Encephalitis
Infected spots
Otitis media
Myocarditis
Glomerulonephritis
Appendicitis
PancreatitisTreatment is symptomatic and includes using paracetamol to manage fever. There is a link between use of ibuprofen in patients with chicken-pox and necrotizing fasciitis so Ibuprofen should NOT be used.
An emollient and antihistamine can be used to ease the itchy rash and oral hydration is encouraged.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 22
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: Ciprofloxacin for 7 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 days
Alternatively, trimethoprim can be used. Duration of treatment is still 14 days -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 23
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 24
Correct
-
Which of the following statements regarding the infectivity periods of these corresponding diseases is correct?
Your Answer: Rubella is infectious until 5 days after the rash appears
Explanation:Rubella can be contagious from 7 days before to 7 days after the rash appears.
Patients with measles are contagious from 1-2 days before the onset of symptoms.
A person with chickenpox is considered contagious beginning 1 to 2 days before rash onset until all the chickenpox lesions have crusted (scabbed).
The infectious period of mumps is considered from 2 days before to 5 days after parotitis onset.
Hepatitis A is highly transmissible and has an average incubation period of 28 to 30 days (range 15–50 days). The maximum infectivity is during the second half of the incubation period (i.e. while asymptomatic) and most cases are considered non-infectious after the first week of jaundice.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 25
Incorrect
-
A patient is diagnosed with a Klebsiella infection.
Which SINGLE statement regarding Klebsiella infections is true?Your Answer: Klebsiella ozanae causes a progressive granulomatous infection of the nasal passages
Correct Answer: Klebsiella spp are an important cause of ventilator-associated pneumonia
Explanation:Klebsiellais a genus of non-motile,Gram-negative, rod-shaped bacteriawith a prominent polysaccharide-based capsule. They are routinely found in the nose, mouth and gastrointestinal tract as normal flora, however, they can also behave as opportunistic pathogens.
Infections with Klebsiella spp. areusually nosocomial. They are an important cause of ventilator-associated pneumonia (VAP), urinary tract infection, wound infection and bacteraemia. Outbreaks of infections with Klebsiellaspp. in high-dependency units have been described and are associated with septicaemia and high mortality rates. Length of hospital stay and performance of invasive procedures are risk factors forKlebsiellainfections.
Primary pneumonia withKlebsiella pneumoniaeis a rare,severe, community-acquired infection associated with a poor outcome.
Klebsiella rhinoscleromatis causes a progressive granulomatous infection of the nasal passages and surrounding mucous membranes. This infection is mainly seen in the tropics.
Klebsiella ozanae is a recognised cause of chronic bronchiectasis.
Klebsiella organisms are resistant to multiple antibiotics including penicillins. This is thought to be a plasmid-mediated property. Agents with high intrinsic activity againstKlebsiellapneumoniaeshould be selected for severely ill patients. Examples of such agents include third-generation cephalosporins (e.g cefotaxime), carbapenems (e.g. imipenem), aminoglycosides (e.g. gentamicin), and quinolones (e.g. ciprofloxacin). These agents may be used as monotherapy or combination therapy. Aztreonam may be used in patients who are allergic to beta-lactam antibiotics.
Species with ESBLs (Extended spectrum beta-lactamase) are resistant to penicillins and also cephalosporins such as cefotaxime and ceftriaxone
. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 26
Correct
-
On his stool culture, a patient with a diarrhoeal illness grows Escherichia coli.
What SINGLE statement about Escherichia coli is true?
Your Answer: Most serotypes are harmless
Explanation:Escherichia coli is a Gram-negative, non-spore forming, facultative anaerobic, rod-shaped bacterium.
Although some can cause serious food poisoning, most serotypes are harmless.
Escherichia coli is transmitted via the faeco-oral route.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 27
Incorrect
-
A patient presents with a fever, headache and neck stiffness. A CSF sample of someone with meningococcal meningitis typically shows:
Your Answer: Low glucose
Correct Answer: All of the above
Explanation:CSF analysis typically shows:
cloudy turbid appearance
raised WCC – predominantly neutrophils
high protein
low glucose (typically < 40% of serum glucose)
Gram-negative diplococci seen under microscopy -
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 28
Incorrect
-
Which of the following microbes adheres to the genital mucosa using fimbriae:
Your Answer: Chlamydia trachomatis
Correct 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 29
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 30
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 31
Correct
-
Which one of these infectious diseases typically has an incubation period of between 1 and 3 weeks?
Your Answer: Chickenpox
Explanation:The incubation period for Chickenpox is 7-23 days (usually around 2 weeks).
Incubation period of botulism is 18-36 hours
Incubation period of Meningococcaemia is 1-7 days.
Incubation period of Gonorrhoea is 3-5 days.
Incubation period of Hepatitis A is 3-5 weeks.
Other infectious with an incubation period of between 1 and 3 weeks are:
Whooping cough (7-10 days)
Brucellosis (7-21 days)
Leptospirosis (7-12 days)
Malaria (7-40 days depending on strain)
Typhoid (8-21 days)
Measles (10-18 days)
Mumps (14-18 days)
Rubella (14-21 days) -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 32
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 33
Correct
-
A patient presents with nausea, anorexia, jaundice and right upper quadrant pain. A diagnosis of acute hepatitis B is suspected.
Which of the following blood results is most suggestive of an acute hepatitis B infection? Select ONE answer only.Your Answer: HBsAg positive, IgM anti-HBc positive
Explanation:Hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, that is the first serologic marker to appear in a new acute infection.It can be detected as early as 1 week and as late as 9 weeks. It can be detected in high levels in serum during acute or chronic hepatitis B virus infection. The presence of HBsAg indicates that the person is infectious. The body normally produces antibodies to HBsAg as part of the normal immune response to infection. HBsAg is the antigen used to make hepatitis B vaccine.
Hepatitis B surface antibody (anti-HBs) indicates recovery and immunity from the hepatitis B virus infection. Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B.
Total hepatitis B core antibody (anti-HBc): Appears at the onset of symptoms in acute hepatitis B and persists for life. The presence of anti-HBc indicates previous or ongoing infection with hepatitis B virus in an undefined time frame. It is not present following hepatitis B vaccination.
IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates recent infection with hepatitis B virus (<6 months). Its presence indicates acute infection.
The following table summarises the presence of hepatitis B markers according to each situation:
Susceptible to infection:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = NegativeImmune due to natural infection:
HBsAg = Negative
Anti-HBc = Positive
Anti-HBs = PositiveImmune due to vaccination:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = PositiveAcute infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = PositiveChronic infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Negative -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 34
Correct
-
A patient with abdominal pain, vomiting and bloody diarrhoea develops a low platelet count and deranged renal function. A diagnosis of haemolytic uraemic syndrome is made.
Which of the following organisms is a recognised cause of haemolytic uraemic syndrome? Select ONE answer only.Your Answer: Escherichia coli
Explanation:E.Colistrain 0157 causes enterohaemorrhagic diarrhoea and can be followed by haemolytic uraemic syndrome (renal failure, haemolytic anaemia and thrombocytopenia).
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 35
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 36
Incorrect
-
Which of the following statements concerning hepatitis D is TRUE:
Your Answer: Hepatitis D is actually protective against hepatocellular carcinoma.
Correct Answer: It can only be transmitted with, or to somebody who is infected with, Hepatitis B.
Explanation:Hepatitis D virus (HDV) is an RNA virus that was discovered in 1977 and is structurally unrelated to the hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV) viruses. HDV causes a unique infection that requires the assistance of HBV viral particles to replicate and infect hepatocytes. Its clinical course is varied and ranges from acute, self-limited infection to acute, fulminant liver failure. Chronic liver infection can lead to end-stage liver disease and associated complications (including accelerated fibrosis, liver decompensation, and hepatocellular carcinoma).
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 37
Correct
-
A patient has a diagnosis of acute osteomyelitis. They have no joint prosthesis on indwelling metal work and no known drug allergies. He has had a recent skin swab that has cultured MRSA and MRSA infection is suspected.
Which of the following antibacterial agents would be most appropriate to prescribe in this case? Select ONE answer only.Your Answer: Vancomycin
Explanation:In the majority of patients the commonest causative organism for osteomyelitis isStaphylococcus aureus.Salmonella spp. are the commonest cause in patients with sickle cell disease.
Other bacteria that can cause osteomyelitis include:
Enterobacter spp.
Group A and B streptococcus
Haemophilus influenzae
The current recommendations by NICE and the BNF on the treatment of osteomyelitis are:
Flucloxacillin first-line
Consider adding fusidic acid or rifampicin for initial 2 weeks
If penicillin allergic use clindamycin
If MRSA is suspected use vancomycin
Suggested duration of treatment is 6 weeks for acute infection -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 38
Correct
-
In adults in the United Kingdom, which of the following pathogens is the most likely cause of viral infectious gastroenteritis:
Your Answer: Norovirus
Explanation:Norovirus is the most common viral cause of epidemic gastroenteritis worldwide; it is also a common cause of endemic diarrhoea in community settings. In the United Kingdom, norovirus has become the most common cause of gastroenteritis in adults and children since the introduction of rotavirus vaccination.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 39
Correct
-
Question 40
Correct
-
In the emergency room, a patient was diagnosed with acute bacterial tonsillitis. Which of the following postinfectious complications is most commonly linked to Streptococcus pyogenes:
Your Answer: Glomerulonephritis
Explanation:Poststreptococcal glomerulonephritis (PSGN) is caused by prior infection with specific nephritogenic strains of group A beta-haemolytic streptococcus. The clinical presentation of PSGN varies from asymptomatic, microscopic haematuria to the full-blown acute nephritic syndrome, characterized by red to brown urine, proteinuria (which can reach the nephrotic range), oedema, hypertension, and acute kidney injury.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 41
Incorrect
-
A 21-year-old student presents with fever, headache, malaise, fatigue, and muscle aches after returning from a trip to India. A diagnosis of malaria was suspected.
Which of the following statements is considered correct regarding malaria?Your Answer: Plasmodium falciparum has the longest incubation period
Correct Answer: Haemoglobinuria and renal failure following treatment is suggestive of Plasmodium falciparum
Explanation:Malaria results from infection with single-celled parasites belonging to the Plasmodium genus. Five species of Plasmodium are known to cause disease in humans: P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.
Chloroquine remains the mainstay of treatment for uncomplicated vivax malaria.
The female Anopheles mosquito serves as the biologic vector and definitive host.
A complication of infection with P. falciparum is blackwater fever, a condition characterized by haemoglobinuria.
Plasmodium ovale has the longest incubation period, which can be up to 40 days. Plasmodium falciparum has a shorter incubation period of 7-14 days.
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 42
Correct
-
Which patients are particularly susceptible to infection with herpes simplex, those with:
Your Answer: T-cell deficiency
Explanation:Cell-mediated immunity, especially the action of cytotoxic T-cells, is essential in the control of herpesvirus infections and patients with T-cell deficiency are at particular risk of reactivation and severe infection. T-cell deficiency may follow HIV infection, chemotherapy, corticosteroid therapy or organ transplantation.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 43
Correct
-
Streptococcus pneumoniae is commonly implicated in all of the following infectious diseases EXCEPT for:
Your Answer: Impetigo
Explanation:Impetigo is a highly contagious infection of the superficial epidermis that most commonly affects young children but can occur in any age group. In children it is the most common bacterial skin infection and it is the third most common skin disease overall, behind dermatitis and viral warts.
The commonest causative organism is Staphylococcus aureus. Streptococcus pyogenesis the second commonest and causes fewer cases, either alone or in combination withS. aureus.The streptococcal form tends to be commoner in warmer, more humid climates. (Hirschmann JV. Impetigo: etiology and therapy. Curr Clin Top Infect Dis. 2002;22:42–51.)
Impetigo is most commonly spread by direct person-to-person contact, and can spread rapidly through families and school classes. It can also, less commonly, be spread by indirect contact.
There are two main forms of impetigo:
Non-bullous impetigo – lesions usually start as tiny pustules or vesicles that evolve rapidly into honey-crusted plaques that tend to be under 2 cm in diameter. These can be itchy but are rarely painful.
Bullous impetigo – lesions have a thin roof and tend to rupture spontaneously. This type is more likely to be painful and may be associated with systemic upset. -
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 44
Correct
-
A 5 day old, full term neonate is with a unilateral purulent eye discharge noticed earlier that day is brought in. On gram stain of the exudate, no bacteria are seen.
What is the most likely causative pathogen?
Your Answer: Chlamydia trachomatis
Explanation:Conjunctivitis occurring in the first 28 days of life (Ophthalmia neonatorum) is most commonly caused by Chlamydia trachomatis in the UK.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 45
Correct
-
Which of the following statements is correct with regards to Klebsiella spp?
Your Answer: They are typically associated with nosocomial infection.
Explanation:Klebsiella is a type of bacteria commonly found in nature. In humans, the bacteria are often present in parts of the digestive tract and respiratory flora, where they do not generally cause problems. They are anaerobic Gram-negative rods. They are usually opportunistic pathogens which cause nosocomial infections, the most common ones being pneumonia and UTI.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 46
Correct
-
A 10-year-old girl that appears systemically well presents with a honey-crusted scab close to the corner of her mouth and states that the area is slightly itchy but not painful. The diagnosis given was impetigo.
What is most likely the mode of transmission of the causative agent of the said diagnosis?Your Answer: Direct contact
Explanation:Impetigo is a common pyoderma that is most often seen in children. Historically, most cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years.
A bullous form of impetigo accounts for approximately 10% of cases. It is caused by strains of S. aureus that produce exfoliative toxins leading to the formation of bullae, which quickly rupture and form a transparent, light brown crust.
Impetigo is spread mainly by person-to-person contact; it is rapidly spread through direct transmission. The diagnosis of impetigo can be made from a Gram stain and culture of the vesicular contents.
-
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 47
Incorrect
-
Regarding control of hospital acquired infection (HAI), which of the following statements is CORRECT:
Your Answer: Autoclaving is a method of disinfection.
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 48
Correct
-
Which of the following antibiotics is the first line of treatment for a patient who has been diagnosed with chlamydia infection?
Your Answer: Azithromycin
Explanation:The Centres for Disease Control and Prevention (CDC) recommends azithromycin, a single 1 g dose, and doxycycline, 100 mg bd for 7 days, as first-line medications for chlamydial infection treatment.
Second-line medications (such as erythromycin, penicillins, and sulfamethoxazole) are less effective and have more side effects
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 49
Incorrect
-
Herpes simplex virus is transmitted most commonly through which of the following routes:
Your Answer: Respiratory droplet spread
Correct Answer: Direct contact spread
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.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 50
Incorrect
-
Which of the following statements regarding hookworm is FALSE:
Your Answer: Hookworm larvae mature into adult worms in the small intestine.
Correct Answer: Transmission of hookworm is via ingestion of contaminated food and water.
Explanation:The hookworm life cycle begins with the passage of eggs from an adult host into the stool. Hookworm eggs hatch in the soil to release larvae that mature into infective larvae. Infection is usually transmitted by larval penetration into human skin (duodenal infection may also be transmitted by the oral route). From the skin, larvae migrate into the blood vessels and are carried to the lungs, where they penetrate the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
SESSION STATS - PERFORMANCE PER SPECIALTY
