Exam 2 Flashcards Preview

Microbiology > Exam 2 > Flashcards

Flashcards in Exam 2 Deck (133)
Loading flashcards...

What are the main virulence factors of N. meningitidis

1. Fimbrae, to attach to nasopharynx
2. capsule, antiphagocytic and different serotypes
3. IgA protease, to destroy IgA of course
4. LPS blebs, systemic inflammation if in blood


How is N. meningitidis spread

Via respiratory droplets among individuals with prolonged contact


What are the natural carriers of N. meningitidis

Only humans


What is the asymptomatic carrier rate of N. meningitidis

~10% of individuals


Who is most susceptible to N. meningitidis

Babies, elderly, late teens, and those who live in crowded conditions


Which of the virulence factors do all invasive strains of N. meningitidis have

Anti-phagocytic capsule


What makes an individual susceptible to N. meningitidis

Lack opsinizing antibodies to the particular strain, and further compromised by respiratory damage (smoking, infection)


What diseases can N. meningitidis cause, and which is the most severe

meningitis (10% fatality) and meningococcal sepsis (40% fatality)


How does meningococcal sepsis cause damage

Bacteria blebs off outer membrane which activates monocytes to produce large quantities of cytokines. This causes systemic inflammation, with decreased blood pressure, disseminated intravascular coagulation, etc "septic shock"


What is meningitis

N. meningitides make their way to the brain and set up home there, where their endotoxin triggers a massive immune response with local and systemic inflammation


What are the methods for prevention of meningococcal disease

antimicrobial prophylaxis of persons in close contact with a carrier, and vaccination


What are some viruses that cause lymphocytic meningitis

coxsackie and polio


What are the main causes of acute purulent meningitis in neonates

Strep. pneumoniae, H. influenza


What are the main causes of acute purulent meningitis in children

H. influenza, N. meningitidis, Strep pneumoniae


What are the main causes of acute purulent meningitis in adults

N. meningitidis, strep. pneumoniae


What are the main causes of acute purulent meningitis in elderly

Strep. pneumoniae


Viruses and bacteria can both cause meningitis and encephalitis, which is more common and which is more deadly

Viral is more common, bacterial is more deadly


Where is Neisseria normally found

It is a normal, hardy, oral species


Are the pathogenic Neisseria bugs hardy?

nope! very fragile actually and drying kills it


Is Neisseria gam positive or negative

Negative, it's got LPS


What is the appearance of Nesseria under the microscope

Pairs, "the official bacteria of starbucks" because it looks like a coffee bean


What are the main virulence factors of N. gonorrhoeae

1. Fimbrae (attachment and escape phagocytosis) 2. Ag-variation of pili structure (gene conversion and phase variation) 3. Surface receptors for host protein (camo) 4. IgA protease 5. LPS 6. Penicillin resistance (beta-lactimase) 7. Intracellular (hide)


Why does N. gonorrhoeae remain a local infection

It doesn't have a capsule


What is the natural reservoir for N. gonorrhoeae

humans, particularly the asymptomatically infected person (usually a woman)


What could happen if a N. gonorrhoeae infection is left untreated

10-20% of untreated women develop pelvic inflammatory disease, which can result in scarring, sterility, and ectopic pregnancy


What risk do newborns have in contracting a N. gonorrhoeae infection

They can get gonorrhoeae in their eyes via the whole birthing process, so they are often treated with antimicrobial drops in their eyes


Why is there no vaccine for N. gonorrhoeae

Because it has so many variable surface antigens (epitopes)


Can you get N. Gonorrhoeae from a toilet seat

extremely unlikely since it is a very fragile bug; needs mucosal contact


What are the top 4 STI's in the US

1. HPV 2. Chlamydia 3. Trichamoniasis 4. Gonorrheae


Where does N. Gonorrhoeae live and replicate

In mucosal cells, usually in the genital tract, occasionally oral or eyes (newborns). They also pass through to the lamina propria