Final; Neisseria Flashcards
Neisseria are the only genus of what that frequently causes disease; and what diseases are an example
gram negative cocci
N. gonorrhoaea
N. menigitidis
What type of motility, oxygen level, and location of pathogenesis goes Neisseria prefer
non-motile
aerobes (but can grow aerobically)
obligate human pathogens
What techniques are used to diagnose neisseria infections
chocolate agar in presence of CO2
modified thayer-martin agar
catalase and oxidase reaction
sugar fermentations
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
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)
How does gonococci encounter and enter the human host
asymptomatic carriers greater among women
upon introduction, attach to columnar epithelial of cervix or urethra
What are the adhesions of gonococci controlled by
phase variation - presence/absence
antigenic variation - composition
What is phase variation of gonorrhoaea
turing on or off the Opa gene which when on results in neutrophil uptake
What is antigenic variation of gonorrhoaea
changes in composition or structure of surface molecules (pili; host cell attachment)
*How does gonococci multiply rapidly
shed in genital secretions
do not have flagella/not motile
can enter epithelial cells
*Extracellular proteases cleave what produced by humans
it cleaves IgA1 removing the Fc receptor and enable stye escape from phagocyotsis
How does gonococci spread and mulitply
attachment to non-ciliated
ciliated cell motility slows and ceases
death of ciliated cells
This is when non-ciliated microvili engulf bacteria; internalized by “parasite directed endocytosis”
internalization
This is when gonococci multiply within vacuoles and then fuse with the basement membrane
intracellular replication
intracellular traffic
How does gonococci induce damage
does not secrete exotoxins
LPS and LOS and other cell wall components cause cell damage
How does neisseria survive in the host
evasion; LOS is similar to human erythrocyte antigens
What are the symptoms of a gonococci infection
localized inflammation
rarely lethal
What are the symptoms of a meningococci infection
uncomplicated bacteremic process
metastatic infection of the meninges
overwhelming systemic infecction
What is the difference in virulence factors between gonococci and meningococci
meningococci is heavily encapsulated and produces hemolysin
A gonococcal infection of the female upper reproductive tract causes what
pelvic inflammatory disease
A gonococcal infection of upper reproductive tract in men causes what
epididymitis
Disseminated gonococcal infections can result from PID due to endotoxin and cause what symptoms
pustular lesions of skin
inflamed joints/tendons
suppurative arthritis
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
How are neisseria infections treated
most are penicillin resistant (and tetracycline)
resistance to other antibiotics are increasing
antimicrobial chemoprophlaxis is primary prevention
*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
