Microbiology Flashcards
List 4 ways in which an STI might present in a woman
Any 4 from: vaginal discharge(+/- urethral, rectal), ulceration (painless/painful), itching, soreness, rashes, lumps/growths, abnormal bleeding (intermenstrual bleeding/post-coital bleeding), abdominal pain, lower back pain, dyspareunia, dysuria, anorectal symptoms, systemic symptoms of infection.
Which of the following statements about chlamydia is true?
(a) Untreated chlamydia leads to PID in 90% of cases
(b) Chlamydia decreases the risk of ectopic pregnancy in women
(c) In terms of the bacteriology there are infectious “elementary bodies” which are extracellular and metabolically active
(d) Chylamydiae are potent inhibitors of inflammation
(e) Nucleic acid amplification tests (NAATs) are now gold standard for diagnosing chlamydia
(e) Nucleic acid amplification tests (NAATs) are now gold standard for diagnosing chlamydia
Untreated chlamydia leads to PID in 30% of cases not 90% (a). Chlamydia increases the risk of ectopic pregancy by nearly 10x, not decrease like (b). The bacteriology of Chlamydiae is that they are infectious elementary bodies that are extracellular and metabolically inactive, not metabolically active like (c); once they move into the cell they form reticulate particles which are metabolically active. They are also potent inducers of inflammation, not inhibitors(d). NAATs are now the gold standard for diagnosis, replacing the old gold standard of tissue culture, making (e) the correct answer.
Which of the following statements about lymphogranuloma venereum(LVG) is correct?
(a) LVG is caused by chlamydia trachomatis serovars A, B and C
(b) LVG is an invasive form of chlamydia, it passes through the epithelial cells and infects distal lymph nodes.
(c) LVG is a tropical STI and is only seen in the developing world
(d) The primary stage of classic early LGV can see a painless, non indurated genital ulcer and accompanying symptoms such as balanitis, proctitis and cervicitis.
(e) LVG can not be diagnosed the same way that other serovars of chlamydia can, it requires a specific test involving testing the serum for LVG antibodies.
(d) The primary stage of classic early LGV can see a painless, non indurated genital ulcer and accompanying symptoms such as balanitis, proctitis and cervicitis.
LVG is caused by Chlamydia trachomatis serovars L1,L2 and L3, not A,B,C, (a) which instead cause the trachoma infection. LVG is an invasive form of chlamydia, it passes through epithelial cells to infect regional lymph nodes, not distal ones (b). LVG is a tropical STI and has highest prevalence in the developing world, however in the last 5 years an ongoing outbreak has been identified in european MSM, therefore (c) is outdated. In the primary stage of classic early LGV you can get a painless, non-indurated genital ulcer and accompanying symptoms such as balanitis, proctitis and cervicitis so (d) is correct. LVG can be diagnosed the same way other chlamydiae can, with normal PCR testing, and for specific ones if LVG is suspected, so (e) is wrong.
Gonorrhoea can be asymptomatic in many women. True or false?
True. Women can sometimes experience discharge, but it is asymptomatic in many.
What is the causative organism in gonorrhoea, including gram status and type (e.g gram positive rods)
The causative organism is Neisseria Gonorrhoeae, which is a gram negative diplococci.
NICE states that the treatment for confirmed or suspected uncomplicated anogenital gonorrhoea is:
(a) Amoxicillin 500mg IM as a single dose, plus ceftriaxone 1g orally as a single dose.
(b) Ceftriaxone 500mg IM as a single dose, plus azithromycin 1g orally as a single dose.
(c) Ceftriaxone 500mg IM as a weekly dose for 2 weeks, plus azithromycin 500mg oral BD for 7 days
(d) Ceftriaxone 500mg IM as a single dose, plus amoxicillin 500mg oral BD for 7 days
(e) Benzylpenicillin 1g IM as a single dose, plus ceftriaxone 500mg oral BD for 7 days
From NICE guidelines: Ceftriaxone 500 mg intramuscular (IM) injection as a single dose, plus azithromycin 1 g orally as a single dose(b).If an IM injection is contraindicated or refused, offer cefixime 400 mg orally as a single dose, plus azithromycin 1 g orally as a single dose.If cephalosporins are contraindicated (for example the person has a true allergy to penicillin-type antibiotics), consider a fluoroquinolone (ciprofloxacin 500 mg, single oral dose or ofloxacin 400 mg, single oral dose) plus azithromycin 1 g, single oral dose.Only prescribe a fluoroquinolone if the infection is known to be sensitive to fluoroquinolones.
With regards to HPV, select the correct option.
(a) Serotypes 6 and 11 cause cervical and anal dysplasia and cancer and serotypes 16 and 18 cause genital warts.
(b) Serotypes 8 and 13 cause genital warts and serotypes 18 and 19 cause cervical and anal dysplasia and cancer.
(c) Serotypes 6 and 11 cause genital warts and serotypes 16 and 18 cause cervical and anal dysplasia and cancer.
(d) Serotypes 6 and 13 cause genital warts and serotypes 11 and 18 cause cervical and anal dysplasia and cancer.
(e) Serotypes 8 and 16 cause genital warts and serotypes 11 and 14 cause cervical and anal dysplasia and cancer.
The correct answer is (c) Serotypes 6 and 11 cause genital warts and serotypes 16 and 18 cause cervical and anal dysplasia and cancer.
What manifestation of disease in an adult infected with Molluscum Contagiosum is highly suspicious of that patient also having HIV?
Facial Molluscum. Facial lesions in adults are highly suspicious of HIV infection. The rule is facial molluscum in an adult is HIV until proven otherwise.
A 24 year old female presents to GUM clinic. She is complaining of vaginal discharge that has an offensive smell. She says she has had a similar episode before but after taking a pill it cleared up. She is sexually active with a regular partner of more than 6 months. What is the most likely diagnosis and how would you treat it?
Most likely diagnosis is bacterial vaginosis, which you would treat with oral metronidazole, 400mg BD for 5-7 days. BV is diagnosed on microscopy of gram stain of discharge, raised pH, whiff test. It is often recurrent and associated with preterm delivery.
A 70 year old man has been brought in to his GP by his wife because he lost sight in his right eye this morning. On further questioning she reveals that he’s had episodes of dizziness, headaches and has been fatigued for the last month. He’s also lost some weight, and become extremely forgetful in the past week and a half, forgetting at times who his wife of 40 years is, and where he lives. As the patient sits during the consultation his legs and arms jerk violently and on neurological examination there is bilateral hypotonia and a loss of power in the legs and arms; and the patient is blind in his right eye. Opthalmoscopy is normal.
What is the most likely cause for this man’s blindness and neurological signs?
This is a classic presentation of sporadic Creutzfeldt–Jakob disease. Sporadic CJD presents with rapid dementia alongside myoclonus, cortical blindness, akinetic mutism and LMN signs. The mean age of onset is 65 years (range 45-75 years). Incidence is 1/million/year (poor bloke) and prognosis is poor with death usually occurring within 6 months.
The cause is uncertain, three possible mechanisms are somatic PRNP (which is the human prion protein gene) mutation, spontaneous conversion of PrPc to PrPsc (soluble protein to an insoluble version which causes all the problems) or possibly environmental exposure to prions.
Diagnosis of sporadic CJD is done by EEG, MRI, CSF and brain biopsy.
Which of the following statements is true?
(a) Tonsillar biopsy is incredibly sensitive and specific in diagnosis of Sporadic CJD.
(b) Variant CJD has an older average age of onset than Sporadic CJD.
(c) Classically in variant CJD you have neurological signs which are then followed by psychological signs.
(d) Genetic causes of CJD are more common than sporadic or acquired.
(e) Gerstmann-Straussler-Scheinker syndrome (GSS) is a characterised by a slowly progressive ataxia.
(e) Gerstmann-Straussler-Scheinker syndrome (GSS) is a characterised by a slowly progressive ataxia.
Tonsillar biopsy is incredibly sensitive and specific in diagnosis of variant CJD not sporadic CJD as in (a). Variant CJD has a younger average of onset (26) than sporadic CJD (65). Classically in variant CJD you have psychiatric signs such as dysphoria, anxiety, paranoia and hallucinations, which are then followed by neurological signs such as peripheral sensory symptoms, ataxia, myoclonus, chorea and dementia, therefore (c) is incorrect as it’s the other way round. Genetic causes of CJD account for around 15% of cases, acquired 5% and sporadic CJD responsible for 80% of cases, therefore (d) is wrong. Gerstmann-Straussler-Scheinker syndrome (GSS) is a characterised by a slowly progressive ataxia so (e) is correct. GSS also causes diminished reflexes and dementia and has an onset age of 30-70 years and a survival of 2-10 years.
List all the parts of CURB65 acronym and how this is used in the management of pneumonia patients.
C - Confusion (AMTS <8) U - Urea > 7mmol/L R - Respiratory rate >30/min B - Blood pressure is hypotensive (Less than 90/60) 65 - >65 years of age.
All of these factors are associated with increased mortality, and help form a framework for management of pneumonia patients, with each element awarding 1 point:
0-1: Treat as an outpatient
2: Consider a short stay in hospital or watch very closely as an outpatient
3-5: Requires hospitalization with consideration as to whether they need to be in the intensive care unit
A 68 year old unkempt gentleman comes in to A&E. He reports feeling suddenly short of breath and feeling feverish. He’s got a productive cough with dirty, brown sputum. He’s also got stabbing pains in his chest when coughing, feels generally unwell and has vomited twice. On examination he is tachycardic and tachypnoeic, and has some dullness to percussion and crepitations on auscultation of his right lung.
What is the most likely causative organism?
(a) Neisseria Meningitidis
(b) Mycoplasma Pneumoniae
(c) Streptococcus Pneumoniae
(d) Influenza A
(e) Rotavirus
(f) Klebsiella pneumoniae
(g) Varicella Zoster
(h) Salmonella Enterica
(i) Legionella Pneumophila
(j) Mycobacterium Tuberculosis
The most likely causative organism is (c), Streptococcus Pneumoniae.
The epidemiology is that it’s prevalent and dangerous. The elderly, children and patients with underlying illnesses (HIV, alcoholism) are particularly at risk.
Strep pneumo can also case URTIs/exacerbation of COPD, meningitis and RARELY endocarditis/cellulitis.
Management of the patient would be to admit (CURB65 score of 2 on the details given in the question) and the antibiotic of choice would be Amoxicillin.
23 year old army cadet presents to GP with a 2 week history of headache, malaise and non-productive cough. Examination of the chest is unremarkable, and early blood tests show normal inflammatory markers.
What is the most likely causative organism?
(a) Neisseria Meningitidis
(b) Mycoplasma Pneumoniae
(c) Streptococcus Pneumoniae
(d) Influenza A
(e) Rotavirus
(f) Klebsiella pneumoniae
(g) Varicella Zoster
(h) Salmonella Enterica
(i) Legionella Pneumophila
(j) Mycobacterium Tuberculosis
The most likely causative organism is (b) Mycoplasma Pneumoniae.
Classically causes outbreaks in institutions and military barracks due to the droplet spread. Examination findings may be minimal compared to radiological. WCC usually normal. Diagnosis is done on serology. Extrapulmonary complications can be CNS involvement, Stevens-Johnson, AIHA.
Management of this patient would be in the community, with a macrolide such as erythromycin.
You’re an F1 working in A&E during a heatwave when over the course of 6 hours, 4 cardiologists come in, all presenting with confusion, fever, headache, myalgia, abdominal pain and diarrhoea. Their initial blood tests come back and they all have hyponatraemia and deranged LFTs.
What is the most likely causative organism?
(a) Neisseria Meningitidis
(b) Mycoplasma Pneumoniae
(c) Streptococcus Pneumoniae
(d) Influenza A
(e) Rotavirus
(f) Klebsiella pneumoniae
(g) Varicella Zoster
(h) Salmonella Enterica
(i) Legionella Pneumophila
(j) Mycobacterium Tuberculosis
The most likely causative organism would be (i), Legionella Pneumophila.
This is a classical presentation of Legionnaires disease. The four cardiologists had been at a convention and due to the heatwave(cheeky detail) the air conditioning had been on. This organism colonises water piping systems including air conditioning. Infection is acquired by inhalation, human to human transmission does not occur.
Treatment in severe cases would be IV erythromycin +/- rifampicin. Treatment of less severe cases would be an oral macrolide like clarithromycin or erythromycin.
21 year old 28+4 week pregnant G1P0 lady presents to her GP with a 5 day history of a flu-like illness with coryzal symptoms, fever and myalgia. She also has SOB and a cough, and on examination she is hypoxic, tachycardic and has crackles on auscultation.
What is the most likely causative organism?
(a) Neisseria Meningitidis
(b) Mycoplasma Pneumoniae
(c) Streptococcus Pneumoniae
(d) Influenza A
(e) Rotavirus
(f) Klebsiella pneumoniae
(g) Varicella Zoster
(h) Salmonella Enterica
(i) Legionella Pneumophila
(j) Mycobacterium Tuberculosis
The most likely causative organism is (d) influenza A.
Under normal circumstances uncommon in adults but a viral URTI commonly precedes bacterial pneumonia.
Risk factors for a viral pneumonia include: pregnancy, immunocompromised, pre-existing cardiopulmonary disease and smoking.
Organisms are influenza A in the vast majority of cases, others include CMV, EBV and VZV which can be life threatening.
Treatment is supportive, however antivirals can be used in serious cases such as oseltamivir which is a neuraminidase inhibitor.
List three common sites of Extra-pulmonary TB
Any three from Lymphadenitis, Brain (TB meningitis or cerebral tuberculoma), Bone (spinal TB - paraspinal abcess, osteomyelitis, discitis), Pericarditis, abdominal (peritonitis, ileitis), genito-urinary (renal, testicular) and misc (skin, liver etc)
