Staining Theory in Microbiology

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What is the first step in the pathogenesis of pulmonary tuberculosis?

Tubercle bacilli spread through the lymphatics to regional lymph nodes

Tubercle bacilli are ingested by alveolar macrophages

Tubercle bacilli multiply intracellularly and form granulomas

Tubercle bacilli reach the alveoli (correct)

What is the term used to describe an infection that affects multiple organs at the same time?

Chronic infection

Localized infection

Systemic infection (correct)

Asymptomatic infection

What is the difference between latent TB and active TB?

Latent TB is when the person has no infection, while active TB is when the person has the infection

Latent TB is when the person has the infection but no disease, while active TB is when the TB bacilli overcome the defense mechanisms and multiply with tissue destruction (correct)

Latent TB is when the person has a positive tuberculin skin test, while active TB is when the person has a negative test

Latent TB is when the person has symptoms of the disease, while active TB is when the person has no symptoms

What is the purpose of the tuberculin skin test (Mantoux test)?

To test for delayed hypersensitivity to TB antigens Signup and view all the answers

What is the purpose of including a known positive smear as a positive control in microscopy for tuberculosis diagnosis?

To ensure the staining procedure is working correctly Signup and view all the answers

How is the result of the tuberculin skin test (Mantoux test) interpreted?

By measuring the diameter of the induration (thickening) in millimeters and considering a reading of greater than 10 mm as positive Signup and view all the answers

What does MOTT stand for in the text?

Mycobacteria Other Than Tuberculosis Signup and view all the answers

Which group of species is known to cause a variety of diseases, especially in children and the immune-suppressed?

Mycobacteria Avium Intracellulare group Signup and view all the answers

Infections by Mycobacterium tuberculosis can occur in different organs due to what factor?

Lack of cell mediated immunity Signup and view all the answers

What percentage of TB cases are HIV-coinfected according to the text?

14-30% Signup and view all the answers

Why is tuberculosis considered particularly severe in AIDs patients?

Infections are caused by multiple resistant species Signup and view all the answers

How do tuberculosis infections initially start, according to the text?

As respiratory infections Signup and view all the answers

What is the purpose of using selective enrichment media for the culture of Mycobacteria?

To provide a suitable environment for the slow-growing and fastidious Mycobacteria to grow Signup and view all the answers

What is the purpose of decontaminating specimens before culture?

To kill the commensals before inoculating the specimen onto the media Signup and view all the answers

What is the typical appearance of M.tuberculosis colonies on Lowenstein-Jensen agar?

Irregular raised pale yellow colonies with a hard texture, usually described as Rough, Tough, and Buff Signup and view all the answers

Which of the following is a manual method used for the culture of Mycobacteria?

Lowenstein-Jensen agar slopes Signup and view all the answers

What is the purpose of using Kirschner's Broth for the isolation of M.tuberculosis?

To make the culture process easier for the microbe to utilize in liquid media Signup and view all the answers

What is the importance of a well-prepared and examined smear in the diagnosis of Mycobacterial infections?

It is the most important step in the diagnosis of Mycobacterial infections Signup and view all the answers

What is the purpose of using fluorescent detection in automated culture methods?

To reduce the time required for culture methods Signup and view all the answers

Which characteristic is used to categorize Mycobacteria into slow growers and fast growers?

Rate of growth Signup and view all the answers

What is an example of a biochemical test used for identifying Mycobacterium species?

Niacin, Nitrate, Heat resistant catalase, Urease Signup and view all the answers

What method can differentiate between M. tuberculosis (MTB) and other Mycobacteria?

NAP test Signup and view all the answers

What happens to the BACTEC reading when Mycobacterium tuberculosis (MTB) fails to grow in the presence of NAP in the NAP test?

The growth reading falls Signup and view all the answers

Why are specialized antibiotics needed for treating Mycobacterial infections?

Because Mycobacteria require a combination of antibiotics for treatment Signup and view all the answers

Which stain is used as the primary stain in the Ziehl-Neelsen staining technique?

Carbol fuchsin Signup and view all the answers

What is the purpose of the decolorizing step in the Ziehl-Neelsen staining technique?

To remove the primary stain from cells without a waxy lipid layer Signup and view all the answers

Which stain is used as the counter-stain in the Auramine staining technique?

Potassium permanganate Signup and view all the answers

Which disease is caused by the Mycobacterium tuberculosis complex?

Tuberculosis Signup and view all the answers

Which group of mycobacteria is associated with opportunistic infections and low-grade infections?

Atypical mycobacteria/Non-tuberculous mycobacteria/MOTT Signup and view all the answers

Which mycobacterial species causes leprosy (Hansen's disease)?

Mycobacterium leprae Signup and view all the answers