Mycobacteria and Related Diseases Quiz

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Questions and Answers

What does the MANTOUX test involve?

Intradermal injection of PPD (correct)

Intramuscular injection of PPD

Oral administration of PPD

Subcutaneous injection of PPD

What is the primary method for diagnosing Mycobacterium leprae?

Chest X-Ray

Nitrate and Niacin Test

Sputum culture

Lepromin Test (correct)

What characteristic growth pattern is associated with Mycobacterium tuberculosis in culture?

Mushroom-like clusters

Flower-like growth (correct)

Round smooth colonies

String-like formations

Which type of Mycobacterium is known as the 'Cross Barred Bacillus'?

Mycobacterium kansasii Signup and view all the answers

What is a common clinical manifestation of leprosy?

Leontiasis facial Signup and view all the answers

Which specimen is typically collected for diagnosis of Mycobacterium leprae?

Tissue juice from earlobes Signup and view all the answers

What type of disease is primarily caused by Mycobacterium marinum?

Fish Tank granuloma Signup and view all the answers

What is the duration of culture maintenance for the diagnosis of Mycobacterium species?

8 weeks / 2 months Signup and view all the answers

What is the result indicating for the Iron Uptake Test when no color change occurs?

Absence of iron uptake Signup and view all the answers

Which of the following is true regarding the Pyrazinamidase Test?

A negative result shows a red color. Signup and view all the answers

What does a positive result in the Heat Stable Catalase Test indicate?

Increased bubbling greater than 45 mm Signup and view all the answers

In the presence of zinc powder, what does a negative color change indicate?

Absence of nitrite Signup and view all the answers

What does positive phenolphthalein indicate in the context of Arylsulfatase testing?

Presence of M.fortuitum Signup and view all the answers

What action should be taken to confirm a negative result in the nitrate reduction test?

Add zinc powder Signup and view all the answers

What is the purpose of using Tween 80 in the identification of Mycobacterium?

To facilitate lipid digestion in colonies Signup and view all the answers

What characteristic result is expected for M.gordonae in the catalase test?

Height of bubbling exceeding 45 mm Signup and view all the answers

What is the primary staining characteristic of Mycobacterium due to mycolic acid?

Difficult to stain but once stained is hard to decolorize Signup and view all the answers

Which Mycobacterium species is commonly associated with leprosy?

M.leprae Signup and view all the answers

Which method is recognized for acid-fast staining?

Ziehl-Neelsen Method Signup and view all the answers

What characteristic does the non-photochromogen group of Mycobacterium exhibit?

They require prolonged incubation for growth. Signup and view all the answers

Which of the following media is known to inhibit contaminating organisms in Mycobacterium culture?

Lowenstein Jensen Media Signup and view all the answers

How is the viability of non-culturable Mycobacterium maintained?

Using mice foot pads Signup and view all the answers

What is the typical arrangement of Mycobacterium seen under a microscope?

Cigar Packet arrangement Signup and view all the answers

What is indicated by a yellow result in the Niacin test on Lowenstein media?

Presence of Mycobacterium tuberculosis Signup and view all the answers

What type of growth medium is formulated for the culture of Mycobacterium that does not use selective antibiotics?

Non-selective agar-based media Signup and view all the answers

In the Runyon Classification, Mycobacterium that do not produce pigment are categorized under what type?

Non-photochromogens Signup and view all the answers

Which Mycobacterium species is predominantly associated with cervical adenitis in children?

Mycobacterium scrofulaceum Signup and view all the answers

Which of the following species is categorized as a non-photochromogen and is associated with pulmonary infections in patients with preexisting conditions?

Mycobacterium avium complex Signup and view all the answers

What type of growth pattern does Mycobacterium phlei exhibit on LJ medium?

Breadcrumbs growth Signup and view all the answers

Which organism is primarily responsible for skin and soft tissue infections, as well as postoperative infections?

Mycobacterium chelonei Signup and view all the answers

Which species of Mycobacterium is characterized by being a rapid grower and is linked to postoperative infections like breast augmentation?

Mycobacterium abscessus Signup and view all the answers

Which of the following Mycobacterium species is NOT typically associated with cervical lymphadenitis?

Mycobacterium malmoense Signup and view all the answers

What is the primary pathogenic effect of Mycobacterium xenopi?

Pulmonary infections in adults Signup and view all the answers

Which of the following Mycobacterium species is biochemically inert and commonly referred to as Buruli ulcer?

Mycobacterium ulcerans Signup and view all the answers

Which mycobacterium species is characterized by a positive Niacin test?

Mycobacterium tuberculosis Signup and view all the answers

Which mycobacterium has a positive Nitrate Reduction Test but a negative Heat Stable Catalase test?

Mycobacterium kansasii Signup and view all the answers

Which of the following tests is consistently positive for Mycobacterium marinum?

Tween 80 Hydrolysis Test Signup and view all the answers

Which mycobacterium species shows a positive result in the Heat Stable Catalase test?

Mycobacterium gordonae Signup and view all the answers

What is the result of the Pyrazinamidase Test for Mycobacterium scrofulaceum?

Negative Signup and view all the answers

Which mycobacterium species has a slow positive response in the Tween 80 Hydrolysis Test?

Mycobacterium asiaticum Signup and view all the answers

Which mycobacterium species does NOT reduce nitrate?

Mycobacterium marinum Signup and view all the answers

What is the result of the Iron Uptake Test for Mycobacterium kansasii?

Negative Signup and view all the answers

Study Notes

Mycobacteria

Aerobic, non-motile
Slow growers and require whole egg for growth
Difficult to stain but once stained difficult to decolorize due to hydroxy methoxy acid / mycolic acid

M. tuberculosis Complex

M. tuberculosis
M. bovis
M. africanum
M. microti & M. canetti

MOTT (Mycobacterium other than tuberculosis)/ Runyon's Classification

Photochromogens
Scotochromogens
Non-photochromogens
Rapid growers

M.leprae

A.k.a. Hansen’s disease
Causes LEPROSY
Non-culturable in vitro, but viability can be maintained using MICE FOOT PADS or FOOT PADS of ARMADILLO
Under the microscope, it forms the so-called Cigar Packet arrangement
Diagnosis is often made based on clinical symptoms

Screening Test: Acid Fast Staining

Ziehl Neelsen
Kinyoun’s method

Culture

Non-Selective
Agar based
Selective
Liquid

Common Disadvantage:

Lowenstein Jensen Media
Petragnani- more inhibitory
American Thoracic Society /ATS
Dorset Egg Media
Wallenstein medium

If (+) Growth in Any of These Media, Next Step Is to Do Series of Biochemical Tests to Identify Species

Biochemical Tests

Niacin test
Nitrate reduction test
Heat Stable Catalase test
Tween 80 Hydrolysis test
Arylsulfatase test
Iron Uptake test
Pyrazinamidase test

M. Tuberculosis

Skin Testing – MANTOUX TEST – involves intradermal injection of PPD on the skin
PPD (purified Protein Derivative) – protein extracted and purified from M. tuberculosis cell wall
OT (old tuberculin)
Von Pirquet (old tuberculin mixed with lanolin to produce ointment, which is scratched onto the skin)

M. bovis

Causes tuberculosis in cattle
Can be transmitted to humans through unpasteurized milk
Nitrate and Niacin Test negative

M. leprae a.k.a. Hansen's Disease

Forms the so-called Cigar Packet arrangement
Non-culturable on artificial media, but can be maintained in the lab using armadillo foot pads or mouse foot pads
Causes Leprosy MOT – prolong skin to skin contact with infected person, droplets from nose & mouth (inhalation)
Clinical manifestation: LEONINE FACE
Tuberculoid type /paucibacillary (limited number of bacteria in the tissues, lesions are usually well-defined and localized)
Lepromatous type /multibacillary (numerous bacteria in the tissues, lesions are widespread and usually poorly defined)
Basis of diagnosis: Lepromin test
Specimen: TISSUE JUICE (earlobes, nasal scrapings)

Non-tuberculous Mycobacteria

Photochromogens

Mycobacterium kansasii – regarded as the # 2 NTM to cause TB in those with AIDS; a.k.a. Cross Barred Bacillus
Mycobacterium marinum- can cause Fish Tank granuloma or Swimming Pool Granuloma
Mycobacterium asiaticum, M. simiae, M. intermedium & M. novocastrense

Scotochromogens

Mycobacterium szulgai - pulmonary disease, predominantly in middle-aged men; cervical adenitis; bursitis
Mycobacterium scrofulaceum - Cervical adenitis in children, bacteremia, pulmonary disease, skin infections
Mycobacterium gordonae / M. aquae (Saprophobic)
M. xenopi - Primarily pulmonary infections in adults. Often produces lemon-yellow colonies on CORN MEAL AGAR
M. flavescens, M. thermresistible
M. interjectum - Unknown Potentially pathogenic Chronic lymphadenitis, pulmonary disease
Others: M. heckeshornense, M. tusciae, M. kubicae, M. cookie, M. hiberniae

Non-Photochromogens

M. avium complex - pulmonary infections in patients with preexisting pulmonary disease; cervical lymphadenitis; and disseminated disease (M. avium pathogenic – LADY WINDERMERE SYNDROME while M. intracellulare = Battey Bacillus)
M. terrae (Scotochromogens)
M. triviale (Photochromogens)
M. gastri, M. ulcerans - mycobacteriosis, also referred to as Buruli ulcer, biochemically inert
M. malmoense M. genovense- Disseminated disease in patients with AIDS
, M. haemophilum, Others: M. heidelbergense; M. simiae; M. shimoidei

Rapid Growers:

M. abscessus subsp. Abscessus - Disseminated disease, primarily in immunocompromised individuals; skin and soft tissue infections; pulmonary infections; postoperative infections
M. fortuitum - Postoperative infections in breast augmentation and median sternotomy; skin and soft tissue infections; pulmonary infections, usually single, localized lesions. Central nervous system (CNS) disease is rare but has high morbidity and mortality
M. chelonei - Skin and soft tissue infections, postoperative wound infections, keratitis
M. phlei – breadcrumbs growth on LJ medium
Others: M. smegmatis – Urine AFB +

Biochemical Tests to Speciate Mycobacterium

Niacin test
Nitrate Reduction test
Heat Stable Catalase test
Tween 80 Hydrolysis test
Arylsulfatase test
Iron Uptake test
Pyrazinamidase test

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Description

Test your knowledge on Mycobacteria, including the characteristics of various species such as M. tuberculosis and M. leprae. Dive into classifications, staining techniques, and culturing methods used in microbiology. Perfect for students studying infectious diseases and microbiology topics.