Infectious diseases & Antibiotics

Question 1

Q fever organism & mx?

Answer 1

Coxiella brunetti (high in farmers)
Mx: doxycycline

Question 2

Rickettsial diseases

Answer 2

Rickettsia rickettsiae - Rocky mountain fever
Rickettsia typhus - endemic typhus
Rickettsia prowazekii - epidemic typhus
Coxiella brunetti - Q fever
Ehrlichia - ehrlichiosis

All (except Q fever) cause pyrexia, headache, morbiliphorm -> vasculitic rash

Mx: Tetracyclines

Question 3

MOA of abx

Answer 3

Inhibit cell wall formation (beta-lactams)
penicillins
cephalosporins
Vancomycin

Inhibit protein synthesis: bateriostatic
aminoglycosides (cause misreading of mRNA)
chloramphenicol
macrolides (e.g. erythromycin)
tetracyclines
fusidic acid

Inhibit DNA synthesis
quinolones (e.g. ciprofloxacin)
metronidazole
sulphonamides
trimethoprim

Inhibit RNA synthesis
rifampicin

Question 4

Microscopy: Neisseria meningitides

Answer 4

Gram negative diplococci

Question 5

Microscopy: Chlamydia trachomatis

Answer 5

Intracellulate gram negative bateria

Question 6

Microscopy: Gardnerella vaginalis

Answer 6

Gram positive coccobacilli

Question 7

Microscopy: Staph aureus

Answer 7

Gram positive cocci in clusters

Question 8

Microscopy: Strep pnemoniae

Answer 8

Gram positive cocci in chains

Question 9

VZV exposure in pregnancy

Answer 9

1. If asymptomatic -> Check antibodies…
   If <20 weeks + no antibodies give IVIG within 3 to 10 day
   If >20 weeks + no antibodies give IVIG or aciclovir within 7 to 14 days
   If antiboies present, no need for IVIG
2. If pregnant and present with rash… for > 20 weeks giver oral acyclovir within 24hrs
   For < 20 weeks give oral acyclovir with caution

Question 10

When do you give VZV IVIG?

Answer 10

1. Pregnant mothers with no antibodies towards VZV
2. Newborn babies with peripartum exposure to VZV

Question 11

Management of maternal chicken pox?

Answer 11

Less than 20 weeks:
Aciclovir with caution

More than 20 weeks:
Aciclovir within 24 hours from onset of rash

Question 12

Antibiotic for gonorrhea

Answer 12

Single dose IM ceftriaxone

Question 13

Antibiotic for chlamydia

Answer 13

Doxycycline OR azithromycin

Question 14

Antibiotic for syphilis

Answer 14

Benzathine benzylpenicillin / doxycycline / erythromycin

Question 15

Antibiotic for BV

Answer 15

Single dose oral Metronidazole or 5-7 day course

Question 16

Antibiotic for PID

Answer 16

Oral ofloxacin + oral metronidazole
OR
IM ceftriaxone + PO doxycycline + PO metronidazole

Question 17

Indication for dexamethasone in meningitis? (4)

Answer 17

1. CSF shows bacteria on Gram stain
2. Purulent CSF
3. WCC >1000 cells
4. Raised WCC + Protein >1.0 gL

Dexamethasone
- give within 4 HOURS of abx administration
- avoid if abx given >12 hours before

Question 18

Association between pneumonia and viral infection
Herpes simplex reactivation –>
Influenza A –>

Answer 18

Herpes simplex reactivation –> Strep pneumoniae
Influenza A –> Staph aureus

Question 19

Leprosy organism & mx?

Answer 19

Leprosy: Mycobacterium leprae

Lepromatous leprosy (multibacillary)
6 skin lesions or more
= DRC (dapsone + rifampicin + clafazimine)

Tuberculoid leprosy (paucibacillary)
5 skin lesions or less
Asymmetric neuro involvement
= DR (dapsone + rifampicin) for 6 months

Question 20

Abx for campylobacter & salmonella & shigella?

Answer 20

Kampylobacter = Klarithromycin
Salmonella = Siprofloxacin
Sigella = Siprofloxacin

Question 21

Anthrax
Organism?
Source?
Feature?
Mx?

Answer 21

ANTHRAX
Bacillus anthracis - gram + rod
Source: Animal carcasses
Feature: painless black eschar
Mx: Ciprofloxacin