MICRO: Actinomyces, C difficile, UTI

Question 1

What is second line for PCP?

Answer 1

Clindamycin and primaquine with IV methylpred

Question 2

What stain is used for PCP?

Answer 2

Methanamine silver

aka Grocott-Gomori

Question 3

When is the viraemic peak in HIV?

Answer 3

4 weeks

Question 4

Which bacterial infections are common if neutrophil defects exist?

Answer 4

Staph

Pseudomonas

Question 5

What infection is most common with complement defects?

Answer 5

Neisseria

Question 6

What are alcoholic patients at risk of?

Answer 6

Actinomyces and other slow growing organisms

Encapsulated organisms

Question 7

What types of infection doe Actinomyces cause?

Answer 7

Lung or brain abscesses which are difficult to treat

Question 8

What are the micro features of actinomyces?

Answer 8

Gram +ve rod that branches (often confused with fungi, Nocardia looks the same)

Question 9

What is a characteristic feature of actinomyces on histopathology?

Answer 9

Basophilic granules or sulfur granules

Question 10

What stain is used for actinomyces?

Answer 10

Grocott

Question 11

List the features of severe C diff according to Imperial guidelines.

Answer 11

Temperature over 38.5
HR >90
WCC >15
Cr rising 
No response to abx in 72hrs 
Severe colitis features

Question 12

What is the management of mild C diff?

Answer 12

Metronidazole 400mg TDS

Question 13

What is the management of severe C diff?

Answer 13

Vancomycin ~200mg +/- metronidazole

Question 14

What is the management of C diff with colonic dilatation?

Answer 14

Metronidazole IV (!) and vancomycin PO

Question 15

What is the management of C diff with ileus?

Answer 15

Intracolonic vancomycin

Question 16

What are the 3 Cs associated with C diff?

Answer 16

Clindamycin
Cephalosporin
Ciprofloxacin

Question 17

What non-Abx drugs can cause C diff?

Answer 17

PPIs (higher pH so more spores survive)

Question 18

Name 2 places where C diff toxins act to cause pseudomembranous colitis.

Answer 18

epithelial junctions –> neutrophils infiltrate

tight junctions –> fluid loss

Question 19

Is CRP high in C diff?

Answer 19

No, commonly low with high WCC

Question 20

What % of UTI are caused by several bacteria?

Answer 20

5%

Question 21

What virulence factor does staph saprophyticus have to cause UTI?

Answer 21

P-fimbrae - adherence to epithelium

Question 22

Other than E coli/SS, what are other causes of UTI?

Answer 22

Proteus m
Klebsiella aerogenes
Enterococcus faecalis
Staph epidermidis

Question 23

What UTI is staph epidermidis associated with?

Answer 23

Prosthesis e.g. catheter

Question 24

What UTI is proteus associated with?

Answer 24

Kidney stones

Question 25

When should you suspect that the UTI has been acquired by haematogenous route?

Answer 25

S aureus - does not have appropriate factors to cause ascending infection

Question 26

How many CFUs are required to diagnose E coli/SS UTI?

Answer 26

> 10^3 CFU/ml

Question 27

How many CFUs are required to diagnose non-Ecoli UTI?

Answer 27

> 10^5 CFU/ml

Question 28

What WCC suggests inflammation in UTI?

Answer 28

> 10^4/ml

Question 29

Describe the agar used for UTI cultures.

Answer 29

CHROMOGENIC - turns different colours based on organism
E coli –> PINK
Other coliform –> BLUE
Gram +ve –> LIGHT blue

Question 30

If UTI symptoms have been present for >7 days how long is the treatment?

Answer 30

7 days

Question 31

What is the management of catheter candida UTI?

Answer 31

Remove catheter - no benefits of antifungals

Question 32

What enzyme forms nitrites in urine?

Answer 32

Nitrate reductase

Question 33

Which part of kidney is more susceptible to infection?

Answer 33

Medulla > cortex

Question 34

What is the tx for pyelonephritis?

Answer 34

Coamox +/- gentamycin