Mycobacteria (EXAM III) Flashcards
Mycobacteria is a _______ bacteria genus
Acid fast
Mycobacteria have _____ in the cell wall
Mycolic acid
The mycolic acid in ______ of the mycobacteria make _____ less effective
Cell wall; gram staining
Describe the gram stain of mycobacteria:
Weak gram + staining
What is used instead of gram stain in mycobacteria?
Acid-fast stain or specific fluorescent detection
Discuss the oxygen requirements of mycobacteria:
Obligate aerobe
What two properties of mycobacterium allow them to grow in lung macrophages:
- Facultative intracellular growth
- Obligate aerobes
_____ are the reservoirs for mycobacteria
Humans
The basis for diseases caused by mycobacteria is ______ transmission
Airborne
As few as ____ cells can result in a mycobacterial infection:
10 cells
Mycobacteria was the first in the first organism met in:
Koch’s postulates
Describe acid-fast staining:
Involves driving a stain into the mycolic acid using a hot carbol fuchsin
Basically along the entire surface of bacterial cell wall structure in mycobacteria:
Glycolipids
Glycolipids on the surface of the bacterial cell wall structure in mycobacteria associate with _____ & cause _____
Mycolic acid; causes cord formation (adjacent cells sticking together)
What is the glycolipids covering the surface of the mycobacterial cell wall referred to as?
Cord factor
What is responsible for the virulence of mycobacteria?
Slow, cord-like growth
Cord-like growth of mycobacteria results from:
Adherence of cell surface lipid mycolic acids with glycol-lipids
Why many factors contribute to the virulence contribute to the virulence of mycobacteria, it is mainly resulting from:
The challenge they provide to the immune response
What do we mean when we say infection with mycobacteria “challenges the immune response”?
It obstructs the CD4+ T cell response in macrophages (Delayed-type hypersensitivity response)
A disease like Leprosy or TB is typcially caused by ____ & not _____
The character of the immune response & not the mycobacteria/toxins themselves
How do the mycobacteria facultatively grow intracellularly in alveolar & other macrophages?
Inhibition of phage-lysosome fusion
Involves a cell-mediated response that will result in a granuloma surrounded by lung tissue & inflammatory leukocytes & contains a central area of necrosis where then nuclei have been destroyed
CMI to mycobacterium tuberculosis
A ______ is surrounded by punctuate nuclei of lung tissue & inflammatory leukocytes
TB granuloma
What is at the center of a TB granuloma?
Central area of necrosis where nuclei have been destroyed
Mycobacterium tuberculosis is a “_____” pathogen
Explain:
Life-long; once infected you may be asymptomatic but never cured
What is the transmission of mycobacterium tuberculosis?
Aerosol
Effective ____ is capable of localizing & stopping infection by M. Tuberculosis
Cell-mediated immune response
What is an exception to the idea that an effective cell-mediated response is capable of localizing & stopping infection of M. Tuberculosis?
Young children under 5 years have a high risk for developing progress TB due to insufficient immune system development/activation
The outcomes of untreated primary TB (for non-immune compromised patients)
_____ show no disease (body keeps in under control)
_____ show clinical TB
_____ show progressive systemic disease & death
91%
6%
3%
Secondary tuberculosis is also known as:
- Acute/open
- Galloping consumption
Secondary tuberculosis is caused by:
Endogenous reactivation of prior infection
While ______ secondary tuberculosis is _____ and _____ is mandatory
Rare; VERY contagious; isolation
Endogenous reactivation of prior TB infection is stimulated by:
- Stress
- Malnutrition
- HIV
Describe what M. Tuberculosis disease arises from:
Tissue destruction by our immune defenses & not by damage caused by the bacterial infection
In M. Tuberculosis, the repeated attempts to remove foci of infection by lung macrophages causes ____ that impairs lung function
Granulomatous lung tissue
Breathing impairment in TB is not due to Tuberculosis bacilli but by the:
Macrophage-induced tissue destruction
A positive tuberculin test to subdermal PPD (processed protein derivative) of the cell wall of the opportunistic intracellular pathogen micro tuberculosis
Mantoux reaction
The Mantoux reaction results form a positive _____ test to _____
Tuberculin; subdermal PPD
What determines whether you have positive or negative TB test?
Depends on strength of reaction
Positive TB test=
Strongly positive TB test=
> 10 mm redness
20 mm redness
Discuss the possibility of a vaccination to M. tuberculosis
Possibility of vaccination with a related mycobacterial species M. Bovus
What species does the M. Tuberculosis vaccine originate from?
M. bovus
Discuss the type of vaccine created for TB:
An attenuated vaccine, meaning it is a live bacterium that is “attenuated” meaning it is NOT capable of infection
Name of the TB vaccine:
Bacille Calmette-Guerin (BCG)
BCG is the vaccine that protects against:
M. Tuberculosis
The BCG vaccination against M. Tuberculosis has _____ in humans but is ______ in________ persons
Little virulence; is infectious; immune-compromised
In what situations night the BCG vaccine for M. Tuberculosis offer some protective immunity?
When given to young children
Why is the BCG vaccine discouraged in the US?
Gives positive tuberculin test; thus removing an important diagnostic screening tool
M. Leprosy is really dependent in terms of course of disease on:
The genetic makeup of the individual that has been exposed
Describe what occurs when a healthy individual with a healthy immune system encounters M. Leprosy:
Cell-mediated (CMI) response conquers disease
Describe what occurs when an individual with a strong TH2-reponse encounters M. Leprosy:
Macropaghes kill nerves; macules & plaques without sensation (good for prognosis for recovery & NOT infectious)
In cases where you have a loss of CMI & TH2-response when encounter with M. Leprosy occurs what will happen?
CTL lysis & loss of tissues including nerves
Main symptoms of this disease is tissue destruction:
M. Leprosy
What is the more severe in terms of tissue loss between Tuberculoid Leprosy & Lepromatous Leprosy?
Lepramatous leprosy
Between Tuberculoid Leprosy & Lepromatous leprosy which is ore widespread with a higher bacterial growth?
Lepramatous Leprosy
Discuss the treatment option for Leprosy:
Multidrug therapy: Dapsone + Rifampin + Clofazamine
What is becoming a problem with Leprosy treatment?
Rising drug resistance
Discuss the virulence factors of M. Tuberculosis:
Ability to survive & live in lung macrophages
Discuss the clinical features of M. Tuberculosis:
Pulmonary (& extrapulmonary) tuberculosis
Discuss the treatment for M. Tuberculosis:
Multi-drug therapy; takes 6-12 months to be effective
Discuss the epidemiology of M. Tuberculosis:
Aerosol (person-to-person), all ages but high risk if immune compromised
Discuss the virulence factors of M. Leprae:
Ability to survive & live within macrophages
Discuss the clinical features of M. Leprae:
Tuberculoid-to-Lepramatous leprosy
Discusss the treatment for M. Leprae:
Multidrug therapy; takes 2+ for full effectiveness
Discuss the epidemiology of M. Leprae:
Close physical contact
ALL pathogenic mycobacterial species have:
Very slow growth rates
What is the gram stain for Nocardia:
Gram + but poor staining
Nocardia belong to the classification of:
Partially acid-fast
What makes nocardia “partially acid-fast”?
Prensence of mycolic acid in cell wall
The acid-fast test is used to distinguish Nocardia from:
Fungal look-alikes
Discuss the virulence factors of Nocardia:
Opportunistic pathogen (in immuno-compromised)