MMSC 428 EXAM 4 | QUESTIONS AND ANSWERS |
LATEST UPDATE | WITH COMPLETE SOLUTION
CMI Answer - immune system response that is important for fighting off
intracellular parasites (FIPs and OIPs), because once they are inside of the cells
antibodies are not helpful
mycobacterium characteristics Answer - -have a lot of hydrophobic myconic
fatty acids in their cell wall, so they do not gram stain well
-gram positive like bacilli
-obligate aerobes
-slow growers
-colonies take 4-6 weeks to appear
-produce dry, flat colonies with irregular filamentous edge that may produce
orange or yellow carotenoid pigment
-catalase + (measured with semiquantitative test)
-have innate resistance to disinfectants and antimicrobial therapies due to slow
growth and hydrophobic cell wall
-show beading (irregular staining) and cording (clumped cells sticking together)
in carbol fuschin stain
-can be classified according to Runyun classification
-MALDI-TOF, high pressure liquid chromatography (HPLC) MIDI, and NAAT are
the best way to identify species
-antibodies are detect with PPD skin test, active infections can be seen with
chest X ray (granulomas)
,Mycobacterium tuberculosis clinical significance Answer - -most important
member of the mycobacterium tuberculosis complex (MTBC)
-causes tuberculosis (LRT infection)
-bacteria cause a delayed type hypersensitivity response that causes
overstimulation of the CMI, which causes the damage that is seen (not the
bacteria)
-bacteria are innately resistant to a lot of drugs and multi-drug resistant strains
are appearing and making it more difficult to treat
-most cases are seen in asia, africa and india
-not seen a lot in the US, most cases are immigrants
-vaccine is available (attenuated M. bovis)
semiquantitative catalase test Answer - hydrogen peroxide is added to bacteria
located in a test tube, and the height of the bubbles produced tells you
approximately how much catalase enzyme is produced by the bacteria
-used to differentiate the mycobacteria species
mycobacterium tuberculosis Answer - -FIP that mainly infects monocytes and
macrophages (latent infection)
-most common mycobacterial infection in the world
-causes respiratory infections
-being a FIP is the most important virulence factor
-gram positive-like cell wall that does not gram stain due to high myconic lipid
content
-produce nonpigmented buff colored (tannish white) colonies in heaping piles
-NO3 (nitrate) +
-niacin +
-heat stable catalase - (is heat labile)
,-sensitive to isoniazid and rifampin
-show a lot of cording (clumping of cells) in microscopy
-gene probes on direct samples, HPLC MIDI and MALDI-TOF are best ways to
identify the speices
mycobacterium bovis Answer - -member of the mycobacterium tuberculosis
complex
-very similar species to M. tuberculosis
-**T2H sensitive**
-produces heat labile catalase
-bacteria that is used to make the vaccine for tuberculosis
-causes a Tb-like disease in humans that is acquired from cows (inhalation or
unpasteurized dairy)
-causes Tb in cows
mycobacterium ulcerans Answer - -found in fresh water and and mud
-grows mainly in the tropics and subtropics (humid)
-**grows at 30 C not 37 C** because it causes a skin infection and the skin is
cooler than the core temp
-Buruli ulcer: bacteria in mud or water is introduced into a lesion that begin
forms a raised nodule and then transforms to a Buruli ulcer
most common mycobacteria (worldwide) Answer - 1. mycobacterium
tuberculosis
2.mycobacterium leprae
3.mycobacterium ulcerans
, mycobacterium kansasii Answer - -**photochromagen** (only member of the
MTB complex that is)
-Runyon classification group 1 (slow growers, photochromagens)
-relatively weak pathogen
-common infection in the US
-NTM lung disease: similar to Tb, but only seen in immunocompromised
individuals
mycobacterium avium complex (MAC) Answer - -found in fresh water, soil and
plants
-is not necessary to identify the species for treating infections, just need to
identify to the level of the complex
-nonchromogenic
-**NAP sensitive**
-Runyon classification group 3 (slow grower, nonchromogenic)
-important human pathogens, infections have increased dramatically since
AIDS epidemic (80's)
mycobacterium avium complex (MAC) clinical significance Answer - -M. avium
and M.intracellularae are very clinically significant
-used to only be seen in older men with history of smoking, since the 80's there
has been a significant increase in cases due to rise in AIDS
-weak pathogens, only infect immunocompromised individuals
-pulmonary disease: Tb-like disease only seen in compromised lungs (HIV, AIDS,
history of smoking)
-cervical lymphadenitis: inhaled bacteria infect cervical lymph nodes in children
(weak immune system)
-disseminated infection: AIDS and HIV patients do not have adequate CMI
response to stop the bacteria from spreading, so secondary infections are seen
around the body
LATEST UPDATE | WITH COMPLETE SOLUTION
CMI Answer - immune system response that is important for fighting off
intracellular parasites (FIPs and OIPs), because once they are inside of the cells
antibodies are not helpful
mycobacterium characteristics Answer - -have a lot of hydrophobic myconic
fatty acids in their cell wall, so they do not gram stain well
-gram positive like bacilli
-obligate aerobes
-slow growers
-colonies take 4-6 weeks to appear
-produce dry, flat colonies with irregular filamentous edge that may produce
orange or yellow carotenoid pigment
-catalase + (measured with semiquantitative test)
-have innate resistance to disinfectants and antimicrobial therapies due to slow
growth and hydrophobic cell wall
-show beading (irregular staining) and cording (clumped cells sticking together)
in carbol fuschin stain
-can be classified according to Runyun classification
-MALDI-TOF, high pressure liquid chromatography (HPLC) MIDI, and NAAT are
the best way to identify species
-antibodies are detect with PPD skin test, active infections can be seen with
chest X ray (granulomas)
,Mycobacterium tuberculosis clinical significance Answer - -most important
member of the mycobacterium tuberculosis complex (MTBC)
-causes tuberculosis (LRT infection)
-bacteria cause a delayed type hypersensitivity response that causes
overstimulation of the CMI, which causes the damage that is seen (not the
bacteria)
-bacteria are innately resistant to a lot of drugs and multi-drug resistant strains
are appearing and making it more difficult to treat
-most cases are seen in asia, africa and india
-not seen a lot in the US, most cases are immigrants
-vaccine is available (attenuated M. bovis)
semiquantitative catalase test Answer - hydrogen peroxide is added to bacteria
located in a test tube, and the height of the bubbles produced tells you
approximately how much catalase enzyme is produced by the bacteria
-used to differentiate the mycobacteria species
mycobacterium tuberculosis Answer - -FIP that mainly infects monocytes and
macrophages (latent infection)
-most common mycobacterial infection in the world
-causes respiratory infections
-being a FIP is the most important virulence factor
-gram positive-like cell wall that does not gram stain due to high myconic lipid
content
-produce nonpigmented buff colored (tannish white) colonies in heaping piles
-NO3 (nitrate) +
-niacin +
-heat stable catalase - (is heat labile)
,-sensitive to isoniazid and rifampin
-show a lot of cording (clumping of cells) in microscopy
-gene probes on direct samples, HPLC MIDI and MALDI-TOF are best ways to
identify the speices
mycobacterium bovis Answer - -member of the mycobacterium tuberculosis
complex
-very similar species to M. tuberculosis
-**T2H sensitive**
-produces heat labile catalase
-bacteria that is used to make the vaccine for tuberculosis
-causes a Tb-like disease in humans that is acquired from cows (inhalation or
unpasteurized dairy)
-causes Tb in cows
mycobacterium ulcerans Answer - -found in fresh water and and mud
-grows mainly in the tropics and subtropics (humid)
-**grows at 30 C not 37 C** because it causes a skin infection and the skin is
cooler than the core temp
-Buruli ulcer: bacteria in mud or water is introduced into a lesion that begin
forms a raised nodule and then transforms to a Buruli ulcer
most common mycobacteria (worldwide) Answer - 1. mycobacterium
tuberculosis
2.mycobacterium leprae
3.mycobacterium ulcerans
, mycobacterium kansasii Answer - -**photochromagen** (only member of the
MTB complex that is)
-Runyon classification group 1 (slow growers, photochromagens)
-relatively weak pathogen
-common infection in the US
-NTM lung disease: similar to Tb, but only seen in immunocompromised
individuals
mycobacterium avium complex (MAC) Answer - -found in fresh water, soil and
plants
-is not necessary to identify the species for treating infections, just need to
identify to the level of the complex
-nonchromogenic
-**NAP sensitive**
-Runyon classification group 3 (slow grower, nonchromogenic)
-important human pathogens, infections have increased dramatically since
AIDS epidemic (80's)
mycobacterium avium complex (MAC) clinical significance Answer - -M. avium
and M.intracellularae are very clinically significant
-used to only be seen in older men with history of smoking, since the 80's there
has been a significant increase in cases due to rise in AIDS
-weak pathogens, only infect immunocompromised individuals
-pulmonary disease: Tb-like disease only seen in compromised lungs (HIV, AIDS,
history of smoking)
-cervical lymphadenitis: inhaled bacteria infect cervical lymph nodes in children
(weak immune system)
-disseminated infection: AIDS and HIV patients do not have adequate CMI
response to stop the bacteria from spreading, so secondary infections are seen
around the body
