Pathogens in the Immunocompromised Host

Question 1

What 3 organisms are associated with a phagocytic deficit?

Answer 1

Staphylococcus aureus: gram-positive cocci

Nocardia: gram-positive, catalas positive, rod

Aspergillus: fungi

Question 2

What organism is a complement deficit associated with?

Answer 2

Neisseria meningitidis: gram negative

Question 3

A B-cell/Ig deficit may be identified due to infection with what 2 organisms?

Answer 3

Streptococcus pneumoniae: gram positive, facultative anaerobe

Haemophilus influenzae: gram negative, cocco-bacilli, facultative anaerobe

Question 4

What organisms are associated with a T-cell deficit?

Answer 4

Fungal:

• Pneumocystis jirovecii pneumnoiae: yeast-like fungus
• Candida albicans: fungus

Viral

Question 5

Are the following immune deficits a deficit in innate or acquired immunity?

Phagocytic

Complement

B-Cell/Ig

T-Cell

Answer 5

Phagocytic: Innate

Complement: Innate

B-Cell/Ig: Acquired/Humoral

T-Cell: Acquired/Cell Mediated

Question 6

What clinical feature is a phagocytic deficit associated with?

Answer 6

Recurrent abscess

Question 7

What system is clinically effected by a B-Cell/Ig deficit?

Answer 7

Pulmonary

Question 8

Chemotherapy may result in a _______ deficit.

Answer 8

Chemotherapy may result in a T-cell deficit. This effects the acquired/cell mediated immune system. Chemotherapy patients may develop fungal (PJP, Candida) or viral (HSV/VZV) infections as a result.

Question 9

After splenectomy, patients will be at risk for infection of 3 types of encapsulated bacteria. What are they?

Answer 9

After splenectomy, patients will be at risk for infection of 3 types of encapsulated bacteria.

1. Streptococcus pneumoniae
2. Neisseria meningitidis
3. Haemophilus influenzae
   * This is due to an Ig equivalent (removal of Ab labelled bacteria) deficit, which is part of the acquired immune system

Question 10

Steroid use results in a deficit of 3 parts of the immune system. What are they?

Answer 10

Steroid use causes a phagocytic, B-cell and T-cell deficit. This effects both innate and acquired immunity. Patients on steroids are at risk for infection with bacteria (nocardia, strep. pneumo) as well as fungus (PJP, Candida).

Question 11

Describe the immune deficit caused by a bone marrow transplant.

Answer 11

A bone marrow transplant results in phagocytic, B-cell and T-cell deficits. These patients will be at risk for bacterial (Nocardia, Strep. pneumo.), fungal (PJP, Candida, Asbergillus) and viral infections (HSV/VZV/CMV).