Final; Neisseria Flashcards by Courtney Kast

Neisseria are the only genus of what that frequently causes disease; and what diseases are an example

gram negative cocci
N. gonorrhoaea
N. menigitidis

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What type of motility, oxygen level, and location of pathogenesis goes Neisseria prefer

non-motile
aerobes (but can grow aerobically)
obligate human pathogens

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What techniques are used to diagnose neisseria infections

chocolate agar in presence of CO2
modified thayer-martin agar
catalase and oxidase reaction
sugar fermentations

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How does meningococci encounter and enter the human host

human nasopharynx
invades mucous membranes
invasion of bloodstream only found in patients lacking complement components C5-C8

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This is used to attach meningococci to the meninges of the CNS and this is used ti damage host tissues

Type IV pili

lipooligosaccharide (LOS)

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How does gonococci encounter and enter the human host

asymptomatic carriers greater among women

upon introduction, attach to columnar epithelial of cervix or urethra

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What are the adhesions of gonococci controlled by

phase variation - presence/absence

antigenic variation - composition

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What is phase variation of gonorrhoaea

turing on or off the Opa gene which when on results in neutrophil uptake

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What is antigenic variation of gonorrhoaea

changes in composition or structure of surface molecules (pili; host cell attachment)

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*How does gonococci multiply rapidly

shed in genital secretions
do not have flagella/not motile
can enter epithelial cells

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*Extracellular proteases cleave what produced by humans

it cleaves IgA1 removing the Fc receptor and enable stye escape from phagocyotsis

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How does gonococci spread and mulitply

attachment to non-ciliated
ciliated cell motility slows and ceases
death of ciliated cells

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This is when non-ciliated microvili engulf bacteria; internalized by “parasite directed endocytosis”

internalization

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This is when gonococci multiply within vacuoles and then fuse with the basement membrane

intracellular replication

intracellular traffic

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How does gonococci induce damage

does not secrete exotoxins

LPS and LOS and other cell wall components cause cell damage

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How does neisseria survive in the host

evasion; LOS is similar to human erythrocyte antigens

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What are the symptoms of a gonococci infection

localized inflammation

rarely lethal

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What are the symptoms of a meningococci infection

uncomplicated bacteremic process
metastatic infection of the meninges
overwhelming systemic infecction

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What is the difference in virulence factors between gonococci and meningococci

meningococci is heavily encapsulated and produces hemolysin

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A gonococcal infection of the female upper reproductive tract causes what

pelvic inflammatory disease

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A gonococcal infection of upper reproductive tract in men causes what

epididymitis

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Disseminated gonococcal infections can result from PID due to endotoxin and cause what symptoms

pustular lesions of skin
inflamed joints/tendons
suppurative arthritis

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Purpura Fulminans (meningococcus) is disseminated intravascular coagulation due to ability to survive in the blood stream and can cause what symptoms

skin manifestations
meningitis
shock
death
the higher the cytokine response to LOS the greater the risk for damage/death

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How are neisseria infections treated

most are penicillin resistant (and tetracycline)
resistance to other antibiotics are increasing
antimicrobial chemoprophlaxis is primary prevention

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*What behavioral methods can be used to prevent neisseria infections

condom use, etc. partner notification early diagnosis and treatment

*Why are vaccines to gonococci difficult to produce

antigenic and phase variation

*What is the vaccine to meningococci

quadrivalent; derived against capsular polysaccharide | tetravalent; polysaccharide protein conjugate (children <2 do not respond)

Where does haemophilus (small gram negative cocci) colonize

upper respiratory tract or almost everyone

*What does H. influenzae require for growth

hemin (X factor) NAD+ (V factor) access to those factors require lysed blood rather than whole blood

*Species of haemophilus require what to grow compared with H. influenzae

require only NAD+ | can grow in whole blood

*What are the tapeable H. influenzae strains

seven antigenically distinct capsular polysaccharides (a, b, c, d, e, e', f)

*What is unique about the non-typable H. influenzae strain

it is unencapsulated

Which staring of H. influenzae is most virulent and what does it cause

``` type B (HIB) bacteremia and meningitis in children younger than 2 ```

What does non-typable strains of H. influenzae cause

frequent causes of respiratory tract diseases in infants, children, and adults

*What virulence factor of haemophilus makes it resistant to phagocytosis (as long as antibody is not present) and is a basis for the vaccine

polyribosyl ribitol phosphate (PRP) capsule

*This virulence factor of haemophilus causes pathogen directed endocytosis

endotoxin

*These virulence factors of haemophilus are similar to that of neissseria (gonococcal)

IgA1 protease | Pili and OM proteains

What host defenses are used against haemophilus

antibodies to capsule | immunization in infants; PRP conjugated diphtheria toxoid

What is the treatment for haemophilus

resistant to penicillins chloramphenicol = drug of choice third-generation cephalosporins corticosteriods reduce complications

Where is pseudomonas aeruginosa (gram negative bacillus) found, what is its motility, and its oxygen level

ubiquitous, found in soil and water motile, polar flagella and pili aerobic; some strains are anaerobic

What are the characteristics of pseudomonas aeruginosa colonies

produce water-soluble pigments that function as antibacterials fruity or grape-like odor

What growth requirements are there for pseudomonas aeruginosa

grow rapidly, very robust minimal nutritional requirement can survive in hand creams, soaps, and dilute antiseptics

What are the two main types of virulence factors of pseudomonas aeruginosa

persistance and dissemination

What type of nutritional aid virulence factors are there for pseudomonas aeruginosa

siderophores (iron binding) | phospholipase C

Where wound someone encounter pseudomonas aeruginosa

soil and water; adheres to veggies and plant matter in water taps, drains, and wet surfaces hot tubs

How does pseudomonas aeruginosa enter the body

opportunistic infection | does not adhere well to healthy epithelium

*After pseudomonas enters the body, the ability to spread and multiply depends on what two things

avoiding phagocytosis | successful adherence to a surface

*Adherence of pseudomonas is mediated by what

flagella and pili | interactions with glycolipid (cleaves sialic acid to create asialo GM1; receptor for type 4 pili) on host cells and TLR5

What is used to facilitate the spread and multiplication of pseudomonas

polysaccharide capsule | cytolytic exotoxins

What does pseudomonas use to damage cells

LPS exotoxins multifunctional enzymes; elastase and lasA type III secretion system delivering virulence factors directly into host cell

With pseudomonas, a predisposing factor leads to what

the type of infection; for example, | a local breach in the immune system due to kidney stones will result in an UTI

*This may cause decreased sialylation of surface glycolipids of which leads to P. aeruginosa binding

cystic fibrosis transmembrane conductance regulator

*Cystic fibrosis and P. aeruginosa also causes dehydration of what, which leads to what

dehydration of respiratory secretions | thick mucus produced which impairs mucociliary system

*This shields P. aeruginosa from immune system, however these strains produce less protease and toxins

mucoid exopolyssaccharide (alginate)

What mediates pseudomonas and sepsis

LPS

What are the three requirements for sepsis

large population of infecting/colonizing organisms presence of bacterial products that stimulate release of host cytokines widespread dissemination of microbial products to roses reticuloendothelial system

Mortality due to pseudomonas depends on

nature and severity of infection host defense state promptness and efficacy of treatment typically for patients with severe infections, it hover ~50%

*True or False | pseudomonas is easily cultured and identified

True

*Antibiotic treatment of pseudomonas depends on what

geographic locale; | in some hospitals certain antibiotic-resistant strains predominate

*Resistance of pseudomonas is due to what

limited permeability of outer membrane, efflux pumps, and antibiotic resistance genes

*What does pseudomonas frequently require to treat it

antibiotic syngerism

Listeria is a gram positive rod found where with two types of mobility

intestinal tract of vertebrates, sewage, soil, and water | food-borne pathogen

Listeriosis can cause what

infections of fetus can result in systemic infections such as bacteremia and meningitis 5-10% of adults are asymptomatic carriers

What are the virulence factors of Listeria

internalins; mediate adherence and invasion listerolysin O; escape from vacuoles phospholipases; escape from vacuoles

What is used to prevent and treat Listeria

control of growth in food supply | antibiotics are effective if diagnosed in time