Microbiology 4: Infection Cases

Question 1

What is the typical appearance of Pneumocystis Jiroveccii pneumonia on CT ?

What happens to them on exercise?

Answer 1

• Bilateral Widespread patchy consolidation + ground glass appearance
• Reduced exercise tolerance

Question 2

Mx of pneumocystis jiroveci pneumonia

Answer 2

Co-trimoxazole

Question 3

How to confirm Dx of PCP

What stain do you use?

Answer 3

Bronchoalveolar Lavage Cytology

silver stain (Grocott-Gomori stain)

Question 4

Which sinus infections are poorly controlled diabetics more susceptible to ?

Answer 4

Rhinocerebral mucormycosis

A fungal infection that infects the sinuses and can invade into the frontal lobes of the brain

The fungi is called Mucor

Question 5

Which organisms are people with complement defficiency more susceptible to ?

Answer 5

• Encapsulated organisms - Neisseria Meningitidis, Streptococcus Pneumoniae

Question 6

Which organisms are people with neutrophil deficiency more susceptible to ?

Answer 6

Staphylococcus infections

Question 7

Which organisms are people with T cell deficiencies more susceptible to ? (4)

Answer 7

• Candida
• PCP
• CMV
• EBV

Question 8

Which indolent infections are more common in alcoholics ?

Answer 8

Actinomycetes lung/ brain abscesses

Question 9

Which histological feature is characteristic of actinomyces infections ?

Answer 9

Basophilic sulphur granules

Question 10

Which antibiotic is recommended for treatment of mild C.diff infections ?

Answer 10

Metronidazole

Question 11

Which antibiotic is recommended for treatment of severe C.diff infections ?

Answer 11

Vancomycin + metronidazole

Question 12

antibiotics for pneumocystitis jirovecii pneumonia

Answer 12

co-trimoxazole

Question 13

what is the main determinant of immune damage in HIV

Answer 13

CD4+ count

Question 14

what type of infections do you get in B cell deficiency

Answer 14

strep, staph
enteroviral encephalitis
giardia
recurrent sinopulmonary infections

Question 15

what type of infections do you get in neutrophil deficiency

Answer 15

staph, pseudomonas
candida, aspergillus

Question 16

common bacteria causing diarrhoea

Answer 16

E coli O157
shigella
salmonella
C. diff

Question 17

what drugs, aside from antibiotics, can cause C. diff

Answer 17

• cytotoxic drugs
• antacids/ PPIs
• non-surgical GI procedures eg NG tube

Question 18

how does C. diff infection present

Answer 18

• explosive, watery, foul-smelling diarrhoea
• high WCC + low CRP

Question 19

Is diarrhoea a marker for severity in C. diff?

Answer 19

not a marker for severity because in very severe C. difficile colitis, you may NOT get any diarrhoea as you could get an ileus which could lead to megacolon

Question 20

Which antibiotics can be associated with C. diff?

Answer 20

ALL - using ABx can disrupt bowel flora and lead to C diff

Question 21

Mx of osteomyelitis

Answer 21

• Removal of devitalised tissues and the prevention of extension of infection by providing adequate drainage is extremely important
• And then give antimicrobials (this alone not useful)

Question 22

Most important part of Tx of prosthetic joint infections

Answer 22

• Removal of prosthesis and adequate debridement is the MOST COMMON part of treatment
• Then can give ABx