MCQ Quiz

1. A major reason lumbar puncture samples for suspected meningitis must NOT be refrigerated is because:

CSF glucose rapidly decreases at low temperature

Fastidious organisms may die and cultures become falsely negative

Protein levels increase artificially

Cells undergo immediate lysis

Explanation:
CSF must be processed immediately without refrigeration because many meningitis pathogens are fastidious and may not survive delay or cold, leading to false-negative cultures.

2. A child with meningitis has lymphocytic CSF, high mortality risk, and temporal lobe involvement. The most likely causative agent is:

Enterovirus

Mycobacterium tuberculosis

Herpes simplex virus

Cryptococcus neoformans

Explanation:
HSV encephalitis presents with lymphocytic CSF and is associated with high mortality if untreated, especially with temporal lobe involvement.

3. Which organism is the MOST common cause of bacterial meningitis overall with the highest mortality?

Streptococcus pneumoniae

Neisseria meningitidis

Haemophilus influenzae type b

Listeria monocytogenes

Explanation:
Streptococcus pneumoniae is the most common cause of meningitis overall and carries a high mortality rate.

4. A neonate with meningitis in a warm climate is MOST likely infected with:

Neisseria meningitidis

Haemophilus influenzae

Streptococcus pneumoniae

Salmonella species

Explanation:
In neonates, especially in warm climates, Salmonella is an important cause of meningitis.

5. Which virulence factor of Haemophilus influenzae type b is responsible for its invasiveness?

IgA protease

Polyribosyl ribitol phosphate capsule

Endotoxin

Fimbriae

Explanation:
The PRP capsule of Hib is the major virulence factor and is antiphagocytic.

6. Failure of Haemophilus influenzae to grow on blood agar is due to:

Lack of iron

Absence of CO₂

Destruction of V factor by NADase

Inhibition by hemoglobin

Explanation:
Blood agar contains NADase which destroys the V factor, preventing growth.

7. Satellitism of Haemophilus influenzae occurs due to:

Release of V factor by Staphylococcus aureus

Hemolysis of red cells

Iron chelation

CO₂ production

Explanation:
Staph. aureus releases NAD (V factor), allowing nearby Haemophilus growth.

8. Which age group is LEAST likely to develop Hib meningitis due to maternal antibodies?

6–24 months

2–4 years

5–10 years

First 2 months of life

Explanation:
Transplacental maternal IgG protects infants during the first 2 months.

9. A child presents with purpura, shock, DIC, and adrenal hemorrhage. The diagnosis is:

Septic shock from pneumococcus

Waterhouse-Friderichsen syndrome

Toxic shock syndrome

Disseminated TB

Explanation:
This fulminant syndrome is classically caused by meningococcal septicemia.

10. Which organism is an intracellular, oxidase-positive, kidney-shaped diplococcus?

Neisseria meningitidis

Moraxella catarrhalis

Streptococcus pneumoniae

Haemophilus influenzae

Explanation:
Meningococci are gram-negative intracellular diplococci with oxidase positivity.

11. Recurrent meningitis following a skull base fracture is MOST commonly caused by:

Neisseria meningitidis

Listeria monocytogenes

Streptococcus pneumoniae

Haemophilus influenzae

Explanation:
Pneumococcus commonly causes recurrent meningitis in skull base fractures.

12. The pneumococcal toxin responsible for inhibiting neutrophil chemotaxis and respiratory burst is:

Autolysin

Capsular polysaccharide

IgA protease

Pneumolysin

Explanation:
Pneumolysin is a membrane-damaging toxin that suppresses host immune responses.

13. India ink preparation is MOST useful for diagnosing meningitis caused by:

Candida albicans

Cryptococcus neoformans

Histoplasma capsulatum

Aspergillus fumigatus

Explanation:
Cryptococcus has a thick polysaccharide capsule visible as a halo on India ink.

14. The primary route of Cryptococcus neoformans infection is:

Inhalation of bird droppings

Skin inoculation

Ingestion of cysts

Sexual transmission

Explanation:
Infection occurs by inhalation of basidiospores from bird droppings.

15. Eosinophilic meningitis is classically associated with ingestion of:

Raw fish

Undercooked pork

Raw or undercooked snails

Unpasteurized milk

Explanation:
Angiostrongylus cantonensis causes eosinophilic meningitis after snail ingestion.

16. Primary amoebic meningoencephalitis is almost always fatal and caused by:

Acanthamoeba

Balamuthia

Entamoeba histolytica

Naegleria fowleri

Explanation:
Naegleria causes rapidly fatal PAM, often linked to warm freshwater exposure.

17. Confirmation of Naegleria infection relies on which laboratory test?

India ink staining

Flagellation test in hypotonic environment

Ziehl-Neelsen stain

Latex agglutination

Explanation:
Naegleria trophozoites transform into flagellates in hypotonic solutions.

18. Granulomatous amoebic encephalitis may be caused by all EXCEPT:

Naegleria fowleri

Acanthamoeba spp.

Balamuthia mandrillaris

Immunocompromised state

Explanation:
Naegleria causes PAM, not granulomatous amoebic encephalitis.

19. First-line treatment for cryptococcal meningitis in immunocompromised patients is:

Fluconazole

Itraconazole

Amphotericin B

Caspofungin

Explanation:
Amphotericin B is required in immunocompromised patients with CNS disease.

20. A child unwell for more than one week with lymphocytic CSF should raise suspicion of:

Enteroviral meningitis

Tuberculous meningitis

Acute bacterial meningitis

Drug-induced meningitis

Explanation:
Prolonged illness with lymphocytic CSF is classically suggestive of TB meningitis.

1# Microbiology of Meningitis

1. A major reason lumbar puncture samples for suspected meningitis must NOT be refrigerated is because:

2. A child with meningitis has lymphocytic CSF, high mortality risk, and temporal lobe involvement. The most likely causative agent is:

3. Which organism is the MOST common cause of bacterial meningitis overall with the highest mortality?

4. A neonate with meningitis in a warm climate is MOST likely infected with:

5. Which virulence factor of Haemophilus influenzae type b is responsible for its invasiveness?

6. Failure of Haemophilus influenzae to grow on blood agar is due to:

7. Satellitism of Haemophilus influenzae occurs due to:

8. Which age group is LEAST likely to develop Hib meningitis due to maternal antibodies?

9. A child presents with purpura, shock, DIC, and adrenal hemorrhage. The diagnosis is:

10. Which organism is an intracellular, oxidase-positive, kidney-shaped diplococcus?

11. Recurrent meningitis following a skull base fracture is MOST commonly caused by:

12. The pneumococcal toxin responsible for inhibiting neutrophil chemotaxis and respiratory burst is:

13. India ink preparation is MOST useful for diagnosing meningitis caused by:

14. The primary route of Cryptococcus neoformans infection is:

15. Eosinophilic meningitis is classically associated with ingestion of:

16. Primary amoebic meningoencephalitis is almost always fatal and caused by:

17. Confirmation of Naegleria infection relies on which laboratory test?

18. Granulomatous amoebic encephalitis may be caused by all EXCEPT:

19. First-line treatment for cryptococcal meningitis in immunocompromised patients is:

20. A child unwell for more than one week with lymphocytic CSF should raise suspicion of: