Diagnosis of Infection

Question 1

Best test to identify cause from an abscess

Answer 1

Gram stain, culture and drug susceptibility testing

Question 2

Can you say something is staph aureus just from looking at it

Answer 2

No

Can only say its staph

Question 3

What colour is staph aureus on an agar plate

Answer 3

Golden

Question 4

What antibiotic should you start for staph in the blood

Answer 4

Vanco if possible

If its already in the blood, want to hit it hard

Question 5

4 best drugs for MSSA

1. 2 oral
2. 2 IV

Answer 5

1. Cloxacillin, cephalexin

2. Cloxacillin, Cefazolin

Question 6

7 best drugs for MRSA

1. 4 oral
2. 3 IV

Answer 6

1. TMP-SMX, Doxy, Linezolid (+/- clindamycin)

2. Vanco, dapto, ceftaroline

Question 7

3 parts of the virus you detect for HepB testing

Answer 7

Surface antigen
Core Ab
Surface Ab

Question 8

What does a positive 
1. Surface antigen
2. Core Ab
3. Surface Ab
tell you about a HepB infection

Answer 8

1. They have a HepB infection (chronic carrier or acute illness)
2. They have been infected at some point
3. Protected via immunity (vaccination)

Question 9

How do you determine if someone has a HepA infection?

Answer 9

Look at IgG and IgM
IgM positive and IgG negative = acute hepA infection
IgM negative and IgG positive = immune from previous infection or vaccine
Both negative = no previous infection and not immune

Question 10

How do you determine if someone has a HepC infection?

Answer 10

Test for the antibody and then viral RNA
Ab +, high RNA = active infection
Ab +, no RNA = previous infection (treated or naturally cleared)
Ab - = no previous infection
There is no vaccine for hepC

Question 11

What does a syphilis rash look like?

Answer 11

Diffuse, erythematous, scaly macular rash

Involves the palms and soles

Question 12

Herpes zoster rash

Answer 12

Vesicles
Painful
Dermatomal distribution

Question 13

3 stages of syphilis

Answer 13

Primary (3-90 days): painless ulcer
Secondary (4-10 weeks): body rash, fever, malaise, systemic symptoms
Latent period
Tertiary (3-15 years): CV disease or neurosyphilis

Question 14

What is the best test to determine if someone has syphilis?

Answer 14

Serology

Question 15

3 things to do when testing for syph in serology

Answer 15

Enzyme immune assay (EIA)
Treponema pallidum Particle Agglutination (TPPA)
Rapid Plasma Reagin (RPR)

Question 16

Antibiotic (and mode) of treatment for syphilis

Answer 16

IM Penicillin

Question 17

If a patient has been infected with HIV in the past 2 weeks, which test is most likely to be positive?

Answer 17

PCR

Question 18

Best test to identify TB

Answer 18

AFB stain

Also want to culture and do drug susceptibility testing

Question 19

How is TB transmitted?

Answer 19

Droplet nuclei

Question 20

What is the biggest risk factor for TB reactivation?

Answer 20

HIV infection (it destroys the CD4 T cells that are suppressing the TB)

Question 21

2 tests to diagnose latent TB infection

Answer 21

Tuberculin skin test

Interferon gamma release assay

Question 22

4 big symptoms of TB

Answer 22

Fever
Cough
Night sweats
Weight loss

Question 23

Antibiotic treatment for TB

Answer 23

Isoniazid
Rifampin
Ethambutol
Pyrazinamide
Need all of these!

Question 24

Someone comes in with a hx of UTIs and wants an antibiotic, what do you do?

Answer 24

Collect a urine sample for urinalysis and culture

If initial dipstick is positive, prescribe and empiric antibiotic based on recent susceptibility data

Question 25

The patient may have a UTI if what 2 things are positive on urine dipstick

Answer 25

Leukocytes and nitrites

If they’re negative its unlikely they have them

Question 26

What does it mean if there are squamous epithelial cells present in the urine?

Answer 26

Sample is likely contaminated

Question 27

Empiric antibiotic for UTIs

Answer 27

Nitrofurantoin