111814 bacteria Flashcards
common bacterial pathogens of upper RT
bordetella pertussis
corynebacterium diphtheriae
neisseria meningitidis
strep pyogenes
common bacterial pathogens of lower RT
staph aureus strep pneumoniae haemophilus influenzae mycoplasma penumoniae pseudomonas aeruginosa legionella aeruginosa mycobacterium tuberculosis
important virulence factors of strep pyogenes
see slide 6
general strategies used by RT pathogens to cause disease
adherence/invasion to RT tissues (pili, fimbriae, adhesins)
secretion of tissue damaging enzymes
factors that inhibit or neutralize host defense (proteases, capsule)
toxins that alter/inactivate host cell fxns (ribosylate G proteins and EF2, phospholipases)
factors that overstimulate immune response (superantigens) form microcommunities (biofilms) to resist elimination
diseases associated with bordetella pertussis infec of RT
whooping cough (pertussis)–catarrhal (high # organisms but little symptoms), paroxysmal (severe clinical symptoms of hacking followed by whoop. few organisms. mostly due to toxin), and convalescence (few organisms)
mechanism of dis elicitation in b pertussis
bacteria binds to ciliated epithelium
pertussis toxin alters adenylate cyclase activity and increases secretions/mucus production
other secreted factors damage the mucociliary escalator
diptheria toxin’s effects
ADP-ribosylates EF2 (inhibits protein synthesis)
important virulence factors of corynebacterium diphtheriae
diphteria toxin
pili
diseases associated with corynebacterium diptheriae infec
non toxin-producing strains: localized infec with pseudomembrane
toxin producing strains: systemic disease
mech of dis elicitation in corynebacterium diptheriae
pili mediate adherence to respiratory epithelium
extensive bacterial replication
diseases associated with neisseria meningtidis infec of RT
pharyngitis
pneumonia
often seen in individuals with underlying dis or in kids
mechanisms of disease elicitation for neis meningitidis
capsule prevents phagocytosis
pili allows colonization of nasopharynx
endotoxin causes most of clinical manifestations
LOS has endotoxin activity
strep pyogenes virulence factors
beta hemolytic
M protein
capsule
diseases associated w strep pyogenes infec of RT
pharyngitis (strep throat)
scarlet fever
strep pyogenes-mechanisms of dis elicitation?
surface proteins promote adherence
localized tissue destruction due to secreted enzymes
scarlet fever due to pyrogenic exotoxins-superantigens
virulence factors: capsule, pyrotenic exotoxins, streptolysin O, streptolysin S
staph aureus–diseases associated with infection of RT?
pneumonia-very young and elderly with underlying pulm disease. acquired via aspiration of oral secretions or hemoatogenous spread from distant infec site
virulence factors of staph aureus
capsule
LTA (like strep pyogenes)-for binding
protein A-binds Fc receptor to prevent clearance
cytotoxins
mechanism of disease elicitation for staph aureus
normal component of nasopharyngeal flora
pulm tissue destruc due to secreted enzymes
can spread to other infec sites to manifest diff disease symptoms
strep pneumo features
alpha hemolytic
diseases associated with infec of the RT for strep pneumo
lobar penumonia
sinusitis
otitis media
mech of dis elicitation for s pneumo
pneumolysin-destroy ciliated epithelial cells, activates alternative complement pathway, suppresses phagocyte oxidative burst
s pneumo-is there a vaccine?
yes
adults and children greater than 2–23 capsular polysaccharide vaccine
for children under 2-13 valent conjugate vaccine
what are the growth requirements for haemophilus influenzae?
heme, NAD
these are unusual growth requirements
diseases associated with haemophilus influenzae infec of RT
pneumonia
sinusitis
otitis
epiglottitis
