L39 Flashcards
Haemophilus influenzae
- GP or GN
- Shape
- Encapsulated or not?
GN Coccobacilli Both encapsulated and not - Non-encapsulated are not typable - Encapsulated type b (Hib) is predominant
What medium do you grow H.influ on? What factors are required?
Chocolate agar
Factor X = hemin
Factor V = NAD
Where in the body does H.influ colonize?
Nasopharynx
What kind of diseases do unencapsulated H.influ cause?
Respiratory tract
- Otitis media
- Sinusitis
- Pneumonia, bronchitis
What kind of diseases do encapsulated H.influ (type B) cause?
Systemic disease via blood
- Meningitis
- Sepsis
- Septic arthritis
What 3 virulence factors do both encap/un-encap H.influ share?
- Adherence factors
- Pili
- Adhensins, especially in un-encap - LOS
- Biofilm
Drugs to treat H.influ non-invasive infections (un-encapsulated)
Amoxicillin
Amox-clavulanate if resistant
Drugs to treat invasive H.influ infections (encapsulated, meningitis)
Ceftazidime/ceftriaxone (3rd gen cephalo)
Which strain of H.influ does the vaccine target?
Encapsulated
Conjugated to a protein
PRP - TT, DT, OMP
Moraxella catarrhalis
- GP or GN
- Shape
GN
Coccobacilli
What 3 diseases does moraxella cause?
Otitis media
Sinusitis
Conjunctivitis - usually w/o symptoms even if it happens
Drugs for moraxella
Amox-clavu
Cephalosporins
Legionella pneumophila
- Shape on lab media
- Shape in tissues
- GN or GP
GN
Poor staining
Lab media = long, thin bacilli
Tissues = short coccobacilli
How is legionella spread?
Aerosols
NOT person to person
Risk factors for legionella
Smoking - chronic lung disease
Old
Immune compromised
Cancer
What are the 2 diseases caused by legionella?
Pontiac Fever
Legionnaires Disease
Symptoms of Pontiac Fever. Treatment.
YOUNG, HEALTHY ADULTS
Flu-like
No antibiotics needed
What are the 3 steps of legionella pathogenesis?
- Attach & enter alveolar macrophages
- IFNg cell macrophage immunity - Form & target vaculoes
- Intracell replication and cell lysis
How does legionella survive in macrophage vacuoles?
Type 4 secretion system:
X phago-lysosome fusion
Vacuole w/ ribosomes (“ER like”) because site of replication
Which stain do you use for legionella?
Gimenez for smears
Dieterle for tissues
Which medium do you culture legionella on?
Buffer charcoal yeast medium
Which 2 tests can you order to diagnose ligionella?
- Urine antigen test
Detects most common strand’s LPS - Sputum direct fluorescent Ab test
Drugs for legionella
Pneumonia:
- Fluoro
- Macrolide
Legionnaires - azithromycin
Coxiella burnetti
- GP or GN
- Shape
- Unique attributes
GN
Bacillus - OBLIGATE INTRACELL (!!!)
Low infectious dose - carries by farm animals
Acute vs chronic diseases caused by coxiella burnetti
Acute = Q fever
- Flu-like
Chronic = endocarditis
Drug coxiella burnetti
Doxycycline
Bordetella pertussis
- GN or GP
- Shape
- Aerobic vs anaerobic
GN
Coccobacilli
NO polysacc capsule
Aerobic
How do you diagnose B.pertussis?
PCR (replaced plate cultures)
Serology
How is B.pertussis spread?
Highly contagious
Aerosols
4 stages of pertussis disease
- Incubation
- Catarrhal - cold
- Paraoxysmal - whooping cough
- Convalescent - resolving
Why do kids die from whooping cough?
Respiratory failure
What are the 3 toxins made by B.pertussis?
Pertussis toxin
Adenylate cyclase toxin
Tracheal toxin
Fxn of pertussis toxin
Ribosylates inhibitory G proteins
Net = lymphocytosis
B/c chemokine receptors of WBCs disabled –> stay in blood stream
Why get systemic symptoms & poor outcomes for kids
Fxn of tracheal toxin
Damages ciliated respiratory epithelium
Drug B.pertussis
Azithromycin - only to prevent spread, doesn’t help symptoms
What is the pertussis vaccine? Cons?
DTaP Diphtheria Tetanus Acellular pertussis Cons: need boosters b/c immunity wanes
