Microbiology

Question 1

If you want to test for chlamydia in a patient, what is the correct method and why?

Endocervical swab for PCR
Vulvovaginal swab for PCR
Vulvovaginal swab for culture

Answer 1

Vulvovaginal swab for PCR

It is not possible to culture chlamydia

Question 2

Endocervical swab for PCR
Vs
Vulvovaginal swab for PCR

What is more invasive?

Answer 2

Endocervical swab

• this is not used routinely
• this is why vulvovaginal swab is used for diagnosis of chlamydia/gonorrhoea

Question 3

Single dose azithromycin is treatment for which STI ?

Answer 3

NONE

• was previously used as a treatment
• not used anymore due to resistance

Question 4

Describe, in microbiological terms, enterococcus faecalis?

Answer 4

Gram +ve cocci

Question 5

How do you define septic shock

Answer 5

Give IV fluid resuscitation but this doesn’t improve the hypotension

Question 6

Major side effect of gentamicin

Answer 6

Autotoxicity

- dizziness

Question 7

In terms of bacterial meningitis, which organism is most common:

Neisseria meningitides
Strep pneumonia

Answer 7

Strep pneumonia

Question 8

Healthy young person with neck stiffness and a non-blanching rash. What is the likely causative organism?

Answer 8

Neisseria meningitides

Question 9

Why are steroids used in the treatment of meningitis? and for what organism are they used in?

Answer 9

Used for strep pneumonia

Steroids help reduce inflammation as there is a lot of inflammation in strep pneumo

Question 10

Which food products is listeria found on?

Answer 10

Soft cheese

Deli meats

Question 11

Why is ceftriaxone used to treat meningitis over penicillin?

Answer 11

Ceftriaxone has a longer half life
More reliable
Lasts longer in the CSF

Question 12

Why is azithromycin no longer used to treat STIs

Answer 12

Concerns in resistance

- peoples infections were not being eliminated

Question 13

Patient comes to the GP and is subsequentally diagnosed with chlamydia. She is given 7 day treatment of Doxycycline. She asks you the following question: “How long do I need to wait until I can resume having unprotected sex with my partner”?

Answer 13

Abstain from sex for 1 week

- wait until completion of treatment

Question 14

A test of cure must be done for both chlamydia and gonorrhoea. True or false?

Answer 14

False

Test of cure is required for gonorrhoea

No test of cure is needed for chlamydia

Question 15

Why is a test of cure not required for chlamydia?

Answer 15

Confident enough that the treatment works so no test of cure needed

Question 16

Asymptomatic male for chlamydia. Which test will he be offered

Answer 16

First pass urine sample 
- For GC/CT PCR 
Blood for 
- syphilis 
- hepatitis 
- HIV

Question 17

It is impossible to investigate an asymptomatic person for herpes. True or false?

Answer 17

True
- wen investigating for herpes simplex virus, you need to deroof the blisters. Therefore, the patient needs to be symptomatic

Question 18

You are in a GP setting and a patient’s STI test results have returned. The patient has gonorrhoea. Should you

• treat the patient in GP setting
• refer patient to sexual health clinic?

Answer 18

Refer patient to sexual health clinic

- then give IM ceftriaxone

Question 19

You are in a GP setting and a patient’s STI test results have returned. The patient has chlamydia. Should you

• treat the patient in GP setting
• refer patient to sexual health clinic?

Answer 19

Treat the patient in the GP setting

- oral doxycycline 7 days

Question 20

Patient on IV AMG treatment for sepsis but it is now day 4 and the patient is still febrile. What do you do in terms of management?

A – drug therapy is OK because amoxicillin will treat most coliforms
B – write another dose of gentamicin
C – write her up for another few days of gentamicin
D – prescribe aztreonam as substitute for gentamicin as this is day 4

Answer 20

D - prescribe aztreonam as substitute for gentamicin as this is day 4

+ stop the amoxicillin and metronidazole as there is no benefit in continuing it

Question 21

Patient has come to A+E with suspected meningitis. She is started on IV ceftriaxone. She later gets a lumbar puncture for CSF analysis and the results are as follows:

150 WBC/mm3
90% lymphocytes 
10% polymorphs
2000 RBC/mm3 
Gram stain – no organisms seen 
CSF glucose is 3.3mmol/L and the blood glucose is 4.2 mmol/L
The CSF protein is raised. 
How do you interpret these results?

Answer 21

This is classic picture of a partially treated bacterial meningitis

• high lymphocyte count
• raised CSF protein

This is also a similar clinical picture to viral meningitis.

It is important to remember the story you are presented with. Remember that the patient was started on antibiotics before LP

Question 22

If you had strongly suspected meningococcal infection, WHEN would it be appropriate to inform the health protection team?

A – within 24 hours of admission
B – when gram film shows meningococci
C – lab confirms Neisseria meningitides has bee cultured
D – reference lab confirms serotype of N meningitides
E – when N meningitides PCR result is confirmed

Answer 22

A