MMSC 428 EXAM 4 | QUESTIONS AND
ANSWERS | WITH COMPLETE SOLUTION
CMI - - Correct 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
legionella pneumophila clinical significance - - Correct answer-:-most clincially
significant legionella, causes about 80% of infections caused by the genus
-serogroups 1-6 are the most common isolates, about 50% of cases are serogroup
1
-reportable disease in the US
-risk factors for infection: immune suppression, smoking, well water, chronic
heart, lung or kidney diseases
-infection occurs by inhalation of contaminated water
-infections are mainly seen in immunocompromised individuals
-associated with hospital acquired outbreaks
-legionellosis has 2 forms (pontiac fever and Legionnaires' disease)
,legionella pneumophila pathogenesis - - Correct answer-:legionellosis has 2
clinical forms, mainly affects people with weakened immune systems
-pontiac fever: mild URT infection with flu-like symptoms that last a few days and
go away on their own (no treatment required, not fatal)
-legionnaires' disease: 1 week incubaiton, mild to severe pneumonia (LRT
infection) with blood tinged sputum, fever, chills, and chest pain followed by
complications (atypical pneumonia, GI disturbance, liver dysfunction, meningitis,
extrapulmonary infections), very fatal if not treated, does not spread from person
to person
legionella mcdadei - - Correct answer-:-second most commonly isolated legionella
-weak pathogen that really only infects immunocompromised individuals
-causes similar infection to legionella pneumophila (pneumoia type infection) but
less severe
legionella isolation procedure - - Correct answer-:-LRT sample: sputum, bronchial
wash with KCl, lung biopsy or bronchial brush
-dilution: dilute samples 1:10 in trypticase soy broth (TSB)or weak KCl solution to
dilute the inhibitory factors
-decontamination: TSB dilutions are incubated at 50 C for 30 minutes, KCl
dilutions are incubated at RT for 4 minutes
-bacteria are plated and incubated at 35 C in increased humidity
Legionella media - - Correct answer-:-nonselective: BYCE alpha (alpha
ketoglutarate for asaccharolytic bacteria), mueller hinton with hemoglobin and
isovitel
-selective: BMPA (BCYE PAC, contains antibiotics), MWY agar
,-differential and selective: BCYE PAV (contains bromocresol purple and
bromothymol blue that legionella will take up and become blue colored
spirochetes (spirochetaceae) characteristics - - Correct answer-:-motile:
corkscrew motility
-endoflagellum: bacteria are wrapped around the flagella
-do not gram stain well, visualized better with dark field microscopy
treponema characteristics - - Correct answer-:-anaerobic
-normal biota of the mucous membranes
-weakly gram negative spirochetes
-culturable in a lab, but not done that often because it would require cell culture
treponema pallidum subsp. Pallidum - - Correct answer-:-culture would require
cells, not done often
-silver stain, dark field microscopy or electron microscopy are good way to
visualize bacteria from a direct clinical sample
-**NAAT is best and most specific diagnosis**
-treponemal and nontreponemal serology available
-causes syphilis (a chronic STD)
-decreased cases since the 40's (penicillin discovered), but recent increase in
cases again
-highest rates in populations of men that have sex with men
treponema pallidum subsp. Endemicum - - Correct answer-:-rare in the US,
common in the middle east
, -endemic syphilis (Bejel): infection of the oral cavity mainly seen in children that
begins with a primary asymptomatic period or low grade fever, progresses to a
secondary period with lesions and papules in the oral cavity and a tertiary severe
phase of skin and bone lesions
-NOT an STD
treponema pallidum subsp. Pertenue - - Correct answer-:-bacteria is mainly seen
in the tropics
-NOT an STD
-Yaws: primary stage has mild symptoms or asymptomatic period, secondary
stage occurs when a mother yaw skin lesion appears with smaller daughter yaws
surrounding it (often on bottoms of feet), and tertiary stage with gummatous
lesions forming on the skin and bones
treponema carateum - - Correct answer-:-mainly seen in the tropics of south and
central America
-not an STD
-Pinta: primary phase occurs when red lesions form on the skin, secondary phase
occurs and leads to hypopigmentation and depigmentation of the lesions, tertiary
phase occurs and hyperkeratosis causes thickening of skin
borrelia characteristics - - Correct answer-:-very large and thick spirochetes
-do not gram stain well, weakly gram negative spirochetes
-easier to visualize due to thickness
borrelia recurrentis - - Correct answer-:-dark field or silver stain microscopy is
best way to visualize
-not usually cultured, kelly medium can be used
ANSWERS | WITH COMPLETE SOLUTION
CMI - - Correct 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
legionella pneumophila clinical significance - - Correct answer-:-most clincially
significant legionella, causes about 80% of infections caused by the genus
-serogroups 1-6 are the most common isolates, about 50% of cases are serogroup
1
-reportable disease in the US
-risk factors for infection: immune suppression, smoking, well water, chronic
heart, lung or kidney diseases
-infection occurs by inhalation of contaminated water
-infections are mainly seen in immunocompromised individuals
-associated with hospital acquired outbreaks
-legionellosis has 2 forms (pontiac fever and Legionnaires' disease)
,legionella pneumophila pathogenesis - - Correct answer-:legionellosis has 2
clinical forms, mainly affects people with weakened immune systems
-pontiac fever: mild URT infection with flu-like symptoms that last a few days and
go away on their own (no treatment required, not fatal)
-legionnaires' disease: 1 week incubaiton, mild to severe pneumonia (LRT
infection) with blood tinged sputum, fever, chills, and chest pain followed by
complications (atypical pneumonia, GI disturbance, liver dysfunction, meningitis,
extrapulmonary infections), very fatal if not treated, does not spread from person
to person
legionella mcdadei - - Correct answer-:-second most commonly isolated legionella
-weak pathogen that really only infects immunocompromised individuals
-causes similar infection to legionella pneumophila (pneumoia type infection) but
less severe
legionella isolation procedure - - Correct answer-:-LRT sample: sputum, bronchial
wash with KCl, lung biopsy or bronchial brush
-dilution: dilute samples 1:10 in trypticase soy broth (TSB)or weak KCl solution to
dilute the inhibitory factors
-decontamination: TSB dilutions are incubated at 50 C for 30 minutes, KCl
dilutions are incubated at RT for 4 minutes
-bacteria are plated and incubated at 35 C in increased humidity
Legionella media - - Correct answer-:-nonselective: BYCE alpha (alpha
ketoglutarate for asaccharolytic bacteria), mueller hinton with hemoglobin and
isovitel
-selective: BMPA (BCYE PAC, contains antibiotics), MWY agar
,-differential and selective: BCYE PAV (contains bromocresol purple and
bromothymol blue that legionella will take up and become blue colored
spirochetes (spirochetaceae) characteristics - - Correct answer-:-motile:
corkscrew motility
-endoflagellum: bacteria are wrapped around the flagella
-do not gram stain well, visualized better with dark field microscopy
treponema characteristics - - Correct answer-:-anaerobic
-normal biota of the mucous membranes
-weakly gram negative spirochetes
-culturable in a lab, but not done that often because it would require cell culture
treponema pallidum subsp. Pallidum - - Correct answer-:-culture would require
cells, not done often
-silver stain, dark field microscopy or electron microscopy are good way to
visualize bacteria from a direct clinical sample
-**NAAT is best and most specific diagnosis**
-treponemal and nontreponemal serology available
-causes syphilis (a chronic STD)
-decreased cases since the 40's (penicillin discovered), but recent increase in
cases again
-highest rates in populations of men that have sex with men
treponema pallidum subsp. Endemicum - - Correct answer-:-rare in the US,
common in the middle east
, -endemic syphilis (Bejel): infection of the oral cavity mainly seen in children that
begins with a primary asymptomatic period or low grade fever, progresses to a
secondary period with lesions and papules in the oral cavity and a tertiary severe
phase of skin and bone lesions
-NOT an STD
treponema pallidum subsp. Pertenue - - Correct answer-:-bacteria is mainly seen
in the tropics
-NOT an STD
-Yaws: primary stage has mild symptoms or asymptomatic period, secondary
stage occurs when a mother yaw skin lesion appears with smaller daughter yaws
surrounding it (often on bottoms of feet), and tertiary stage with gummatous
lesions forming on the skin and bones
treponema carateum - - Correct answer-:-mainly seen in the tropics of south and
central America
-not an STD
-Pinta: primary phase occurs when red lesions form on the skin, secondary phase
occurs and leads to hypopigmentation and depigmentation of the lesions, tertiary
phase occurs and hyperkeratosis causes thickening of skin
borrelia characteristics - - Correct answer-:-very large and thick spirochetes
-do not gram stain well, weakly gram negative spirochetes
-easier to visualize due to thickness
borrelia recurrentis - - Correct answer-:-dark field or silver stain microscopy is
best way to visualize
-not usually cultured, kelly medium can be used
