Mycobacterial Infection - Genus Features Quiz

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Questions and Answers

What is the unique feature of mycobacteria's cell wall?

It is gram-positive

It requires special stains for visualization (correct)

It is easily visualized on artificial media

It is gram-negative

What is a helpful feature in the identification of some Mycobacterium species?

Gram-negative staining

Gram-positive staining

Production of a pigment (correct)

Rapid growth on artificial media

How long does it take for most pathogenic mycobacteria to grow on artificial media?

6-8 weeks

1 hour or less

Several weeks (correct)

1-2 days

What distinguishes Mycobacterium tuberculosis from most other bacteria in terms of growth?

Slow growth Signup and view all the answers

What type of bacteria are mycobacteria?

Aerobic, acid-fast bacilli Signup and view all the answers

What is a unique characteristic of mycobacteria in terms of staining?

They are neither gram-positive nor gram-negative Signup and view all the answers

What is the term 'acid-fast' referring to in the context of mycobacteria?

Ability to retain the carbol fuchsin stain despite ethanol treatment Signup and view all the answers

What is the primary cause of the acid-fast property of M. tuberculosis?

Presence of mycolic acids in the cell wall Signup and view all the answers

In which form does tuberculous meningitis (TBM) usually evolve over 1–2 weeks or longer?

Subacute Signup and view all the answers

Which clinical feature is often a subtle initial presentation of tuberculous meningitis (TBM)?

Low-grade fever and night sweats Signup and view all the answers

Which imaging technique is necessary to establish the diagnosis of tuberculoma and differentiate it from malignancies?

MRI with contrast Signup and view all the answers

What is a frequent finding in tuberculous meningitis (TBM) related to cranial nerves?

Paresis of ocular nerves Signup and view all the answers

What is the characteristic presentation of tuberculoma in the CNS?

Space-occupying lesions usually causing seizures and focal signs Signup and view all the answers

Which group is most at risk for developing tuberculous meningitis (TBM) in the CNS?

Young children and adults infected with HIV Signup and view all the answers

What accounts for approximately 5% of extrapulmonary tuberculosis cases?

Tuberculous meningitis (TBM) Signup and view all the answers

Which type of tuberculosis presents as dormant tubercle bacilli in several organs, with reactivation occurring in adult life?

Post-primary tuberculosis Signup and view all the answers

Study Notes

Mycobacteria Characteristics

Mycobacteria have a unique cell wall feature: a thick peptidoglycan layer and a high content of mycolic acids.
The presence of mycolic acids is a helpful feature in identifying some Mycobacterium species.

Growth and Characteristics

Most pathogenic mycobacteria take 2-4 weeks to grow on artificial media.
Mycobacterium tuberculosis grows slowly, distinguishing it from most other bacteria.

Classification and Staining

Mycobacteria are a type of acid-fast, Gram-positive bacteria.
A unique characteristic of mycobacteria is that they retain certain dyes, such as fuchsin, even when washed with acid.
The term 'acid-fast' refers to this ability to retain dyes despite acid washing.
The primary cause of the acid-fast property of M. tuberculosis is the high content of mycolic acids in the cell wall.

Tuberculous Meningitis (TBM)

TBM usually evolves over 1-2 weeks or longer into a subacute or chronic presentation.
A subtle initial presentation of TBM is often a low-grade fever and headache.
Imaging techniques, such as contrast-enhanced MRI, are necessary to establish the diagnosis of tuberculoma and differentiate it from malignancies.
A frequent finding in TBM is cranial nerve palsies, particularly involving the 3rd, 4th, 6th, and 7th nerves.
The characteristic presentation of tuberculoma in the CNS is a ring-enhancing lesion on imaging studies.
Individuals with HIV/AIDS are most at risk for developing TBM in the CNS.
TBM accounts for approximately 5% of extrapulmonary tuberculosis cases.

Latent Tuberculosis

Latent tuberculosis presents as dormant tubercle bacilli in several organs, with reactivation occurring in adult life.

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Description

Test your knowledge about the genus features of mycobacteria, including their unique cell wall and their significance as important causes of human diseases such as tuberculosis. Explore the characteristics and special staining requirements of mycobacteria in this quiz.