Fastidious Gram Negative Rods (Exam 1) Flashcards
What does it mean if an organism is fastidious
difficult to grow, only grows in specially fortified artificial culture media
What are the different organisms within the haemophilus family
Haemophilus inflenzae
Haemophilus aegypticus
Haemophilus ducreyi
Haemophilus parainfluenzae
What does haemophilus aegypticus
conjunctivitis (pink eye)
What does haemophilus ducreyi cause
chancroid (STD)
What does haemophilus parainflenzae causes
URTI, LRTI, endocarditis
How will the gram stain of haemophilus inflenzae appear
gram negative coccobacilli
What growth medium will haemphlus inflenzae grow on
chocolate agar
What factors do h. influenzae need
factors X and V
Will h. inflenzae grow on blood or macconkey agar
neither
What growth factors are required for h. inflenzae
X= hemin
V=NAD
What is the major virulence factors of haemophilus inflenzae
polysaccharide capsule
IgA protease
endotoxin LPS
WHat type of capsule is found on H. inflenzae type B
polyribitol phosphate
What makes certain strains of H. inflenzae untypeable
lack capsule
What does H. inflenzae cause in infants
meningitis
What are the clinical diseases associated with H. influenzae
meningitis
epiglottis
cellulitis
What age group is most at risk for H. inflenzae meningitis
3-18 months
What age is most at risk for H inflenzae epiglottis
2-4 years, mostly male
What occurs in epiglottitis H. influenzae
cellulits, swelling of the epiglottis
What occurs in H. inflenzae cellulitis
periorbital, cheeks rash
How is H. inflenzae diagnosed
gram stain
culture
satellit phenomenon with S. aureus
growth on chocolate agar
What diseases are associated with nontypeabale H. inflenzae
acute otitis media
sinus infections
acute bronchitis
How will aggregatibacter actinomycetecomitans appear on gram stain
negative coccobacillus
What are the characteristic of growth of aggregatibacter actinomycetcomitans
sticky bacteria, grows slowly in culture
Where are aggregatibacter found
natural flora of the mouth
What are the virulence factors associated with aggregatibacter
adherence proteins
biofilm polysaccharides
LtxA leukotoxin
What organism is associated with juvenile periodontitis
aggregatibacter actinomycetemcomitans
How will endocarditis associated with aggregatibacter actinomycetemcomitans present
3 months to present; significant embolization and bruising in extremities
What are the most common causes of endocarditis
haemophilus parainflenzae cardiobacterium hominus eikenella corrodens kingella kingae aggregatibacter
How will Bordetella pertussis appear on gram stain
gram negative coccobacillus
What virulence factors are associated with bordetella pertussis
filamentous hemagglutinin pertactin tracheal cytotoxin pertussis toxin adenylate cyclase toxin
What role does filamentous hemagglutinin play in virulence of bordetella pertusis
binds to ciliated cells in the trachea
What role does pertactin play in virulence of bordetella pertusis
binds to ciliated cells in the trachea
What role does the tracheal cytotoxin play in virulence of bordetella pertussis
low: ciliostasis
High: cytotoxic
How does bordetella pertusis affect the cilia of the epithelial cells of the respiratory tract
causes stasis of the cilia and prevents clearance of mucus
What are the toxins associated with bordetella pertusis
pertussin toxin
adenylate toxin
What is the MOD of pertussis toxin
ADP ribosylation of Gi
What is the MOD of adenylate toxin
increase conversion of ATP to cAMP
How does the pertussis toxin compare to the cholera toxin
inhibits Gai to increase cAMP to increase production of mucus
How is bordetella pertussis transmitted. What is the reservoir
humans:
person to person transmission
What is the clinical presentation of pertussis
bacterial number peaks during catarrhal; you spread the infection before the charachteristic courgh
Pertussis toxin causes infiltration of what
leukocytes (leukocytosis)
Leukocytosis is unsual for what
bacterial infections typically
What are the 3 stages of pertussis
catarrhal
paroxysmal
convalescent
What are the symptoms during catarrhal stage
runny nose, low grade fever, mild occasional cough, highly contagious
What are the symptoms during paraoxysmal stage
numerous rapid coughs followed by whoop sound, vomitins, and exhaustion after coughing fits
What are the symptoms during convalescent phase
gradual recovery, coughing lessens but fits of coughing may return
What type of vaccines are available
whole cell: inactivated vaccine
acellular vaccine
What are the side effects of whole cell vaccine
neurological problems especially
What is part of the acellular vaccine
pertussis toxin+ FH, fimbriae, pertactin
What are the vaccines for pertussis
DTP,, DTap, Tdap
What form of the pertussis vaccine can be given to pregnant women
Tdap
How is pertussis diagnosed
nasopharyngeal aspirate
Regan Lowe charcoal medium
direct fluorescent antibody staining
PCR
What type of agar can be used for Bordetella pertussis
Regam Lowe charcoal medium
What is the treatment for pertussis
macrolides (erythromycin, azithromycin, clarithromycin)
immunize
hospitalize
DOC
Paryoxysms unaffected by treatment
What disease is associated with bordetella parapertussis
milder whooping cough
What is not produced in bordetella parapertussis infecitons
pertussis toxin
What diseases are associated with bordetella bronchiseptica
kennel cough in dogs
snuffles in rabbits
atrophic rhinitis in swine
Who is most at risk of getting infected with legionella pneumophilia
nosocomial
smokers
high alcohol intake
How is legionella pneumophilla spread
contaminated aerosols
Where will legionella be found within the host
alveolar macrophages, monocytes, and alveolar epithelial cells
What do legionella prevent as part of virulence factor
phagolysosomal fusion
HOw might legionella survive outside of the host
multiply in free living amoeba
What are the natural hosts for legionella
amoeba
How does legionella cause tissue damage
prevents phagosome and lysosome fusion, stimulates immune response which causes damage
What is the incubation and clinical manifestation of legionnaire disease
2-10 days
abrupt onset of fever, headache, pleurisy, chills, myalgia, dry cough
multiorgan involvement
What is pontiac fever
mild systemic disease with symptoms resembling inflenza, caused by legionella infection
How will legionella appear on gram stain
pleomorphic gram negative rods
What stains legionella better than a gram stain
dieterle silver stain
What agar is used to diagnose legionella
buffered charcoal yeast agar
What growth requirements are needed to grow legionella
L cysteine and iron salts
What are the two main lab tests used for diagnosis of legionella
urinary antigen tests
nucleic acid amplification assays
What does urinary antigen tests test for
LPS antigens in urine
