Infectious Diseases

Question 1

2 examples of gram positive organisms and how they stain

Answer 1

Streptococci, staphylococci

Gram positive - retains crystal violet stain, appear purple

Question 2

How to differentiate between gram +ve cocci

Answer 2

Catalase test - staph is positive, strep negative

Use coagulase test for staph - staph aureus is coagulase positive

Question 3

Give a gram negative cocci

Answer 3

Neisseria meningitidis or n.gonnorhoeae

Question 4

2 examples of alpha haemolytic strep

Answer 4

Streptococcus pneumoniae

Strep viridans

Question 5

Example of beta haemolytic strep

Answer 5

Streptococcus pyogenes - group A lancefield strep

Question 6

2 lactose fermenting and 2 non lactose fermenting gram negative bacilli

Answer 6

lactose fermenting - Escherichia coli, Klebsiella

non - salmonella, shigella

Question 7

What colour do gram negative organisms stain

Answer 7

Pink - cell wall does not take up the violet stain

Question 8

What is ziehl-nelson stain used for?

Answer 8

Mycobacteria - gram positive but do not take up gram stain due to outer layer

Question 9

What causes TB?

Answer 9

Mycobacterium tuberculosis
(acid fast bacillus - ziehl nielson)
Droplet spread.

Question 10

What is multi drug resistant TB?

Answer 10

TB resistant to at least isoniazid and rifampicin

Question 11

How is TB diagnosed?

Answer 11

Sputum sample for culture and microscopy

Ziehl Nielson stain or auramine-phenol staining and fluorescent microscopy, or PCR

Question 12

Symptoms of TB?

Answer 12

Weight loss
Cough
Night sweats

Caseating granuloma

See resp for more

Question 13

Common place for TB infection?

Answer 13

Apex of lung - less blood supply

Question 14

Treatment of TB?

Answer 14

Rifampicin - 6mo
Isoniazid - 6mo
Pyrazinimide - 2mo
Ethambutol - 2mo

1st 3 hepatotoxic - hepatitis

Question 15

Side effect of ethambutol?

Answer 15

Optic neuritis

Question 16

Side effect of isoniazid?

Answer 16

Peripheral neuropathy

Question 17

Side effect of rifampicin?

Answer 17

Red urine

Question 18

Side effect of pyrazinimide?

Answer 18

Arthralgia

Question 19

5 C’s ABX associated with C.difficile

Answer 19

Ciprofloxacin
Clindamycin
Cephalosporins
Co-amoxiclav
Carbapenems

Question 20

Which bacteria is responsible for Legionnaire’s disease?

Answer 20

Legionella pneumophilia

Spread by inhalation of mist from aircon, hot water tanks infected

Question 21

Symptoms of Legionnaire’s (4)

Answer 21

Flu like symptoms, fever
DRY cough
Bradycardia
Confusion

Question 22

Investigations for Legionnaire’s

Answer 22

Bloods - lymphopaenia, deranged LFTs, hyponatraemia
CXR - pleural effusion
Sputum culture
Urinary antigen - legionella

Question 23

How is legionnaire’s graded

Answer 23

CURB 65

Question 24

How is legionnaire’s treated?

Answer 24

Erythromycin
OR fluoroquinolone i.e. ciprofloxacin
Notify PHE

Question 25

Complications of legionella?

Answer 25

Empyema
Liver failure
Kidney failure
Respiratory failure
Sepsis
Death