Microbiology

Question 1

When do you give prophylaxis to AIDS/HIV patients against Mycobacterium Avium?

What antimicrobial do you give?

Answer 1

When CD4+ count < 50

Azithromycin

Question 2

How does N. Meningiditis spread?

Answer 2

Via respiratory or oral secretions

Question 3

What does N. Gonorrhoea cause?

Answer 3

1) Gonorrhoea (cervicitis, urethritis, PID –> Fitz-hugh-curtis syndrome)
2) Septic arthritis
3) Neonatal conjunctivitis (within first 2-5 days)
4) Disseminated gonococcal

Question 4

What is the classical triad of disseminated gonococcal?

Answer 4

1) Polyarthralgia
2) Tenosynovitis
3) Dermatitis (painless pustules on extremities)

Question 5

What does N. Meningiditis cause?

Answer 5

Meningitis
Meningococcaemia
Waterhouse-Friderichsen syndrome (adrenal insufficiency, shock, DIC)

Question 6

Antibiotics for gonorrhoea urethritis

Answer 6

Ceftriaxone + azithromycin (single dose)

*Azithromycin provides coverage for concurrent chlamydial infection. Even if test for chlamydia is negative, combination treatment is more effective due to increasing antibiotics resistance. Combination treatment is also more effective for concurrent pharyngeal infection.

Question 7

Antibiotics for meningitis

Answer 7

Ceftriaxone or Penicillin G

Question 8

Prophylaxis for meningitis

Answer 8

Ceftriaxone, ciprofloxacin or rifampin

Question 9

When do you vaccinate babies against H. Influenzae type B?

Answer 9

Between 2 and 18 months old

Question 10

How is H. Influenzae transmitted?

Answer 10

Via aerosol

Question 11

Antibiotics for H. Influenzae?

Answer 11

Augmentin for mucosal infection
Ceftriaxone for meningitis
Rifampin for prophylaxis

Question 12

How is Pertussis transmitted?

Answer 12

Via aerosol

Question 13

How is Legionella transmitted?

Answer 13

Via aerosol from environmental water sources (e.g. air conditioning systems, hot water tank, etc)

Question 14

How is Legionella detected in the lab?

Answer 14

Gram stains poorly -> use silver stain
Grows on charcoal yeast extract medium with iron and cysteine

Antigen can be detected in urine.

Question 15

What does Legionella cause?

Answer 15

Pontiac fever (mild flu-like illness)

Legionnaires (severe pneumonia, GI and CS symptoms) in chronic smoker and lung disease

Question 16

Antibiotic treatment for Legionella?

Answer 16

Macrolide or quinolones

Question 17

Antibiotics effective for Pseudomonas

Answer 17

Carbapenems
Aminoglycosides
Monobactam
Polymyxin (e.g. Colistin)
Fluoroquinolones
thIRd/fourth-gen cephalosporins (e.g. Ceftazidime)
Extended-spectrum penicillin (e.g. Piptazo)

Question 18

What kind of people are more susceptible to cholera infection?

Answer 18

People with reduced gastric acidity (e.g. use of PPI, neonates)

Question 19

Triple therapy for H. Pylori?

Answer 19

Clarithromycin + Amoxicillin + PPI (x 14 days)

Replace Amoxicillin with metronidazole if allergic.

Question 20

Treatment for Lyme Disease?

Answer 20

Doxycycline (1st line)

Cefuroxime or amoxicillin in pregnant woman or children.

Question 21

Treatment for Chlamydia?

Answer 21

Azithromycin (preferred as one time dose only)
Doxycycline (2nd line)
+/- ceftriaxone (for concomitant gonorrhoea infection)

Question 22

Symptoms of lymphogranuloma venerum?

Answer 22

Small, painless ulcers on genitals

Swollen, painful inguinal lymph nodes that ulcerates (buboes)

Question 23

Difference between gonorrhoea vs chlamydia neonatal conjunctivitis

Answer 23

Gonorrhoea: 2-5 days after birth. Pus +++
Chlamydia: 1-2 weeks after birth. Not so much pus

Question 24

Treatment for mycoplasma pneumoniae?

Answer 24

Macrolide or fluoroquinolone or doxycycline

Question 25

Treatment for Pertussis?

Answer 25

Macrolide

Question 26

Clinical presentation of Pertussis?

Answer 26

1) 1-2 weeks of catarrhal phase
2) 2-8 weeks of paroxysmal phase (post-tussive emesis in infants usually not seen in adults. Adults may experience post-coughing haemoptysis instead, cough worse at night)
3) Weeks to months of convalescent phase

LYMPHOCYTIC PREDOMINANT LEUKOCYTOSIS

Question 27

_____ antitoxin can be used to treat botulism

Answer 27

Equine antitoxin