Daniels -Strep Flashcards
Properties of streptococcus pneumoniae
Gm + Diplococci Aerotolerant anaerobe Non-spore forming Encapsulated Catalase - Optochin susceptible
Steps of pathogenesis of S. pneumoniae
- Alveoli fill with fluid
- Early consolidation phase
- Suppurative (PMN) inflammation
- Late consolidation phase
- Alveoli & airways packed w/ neutrophils
- Affected tissue is solid instead of spongy
- Recovery phase
- Macrophages phagocytose debris
- Normal architecture is reestablished
What are some potential sequelae to pneumonia in adults?
Pleural effusion (fluid in chest outside lungs)
Bacteremia -> meningitis
[otitis media in children]
What types of therapy are there for pneumococci
Penicillins & other B-lactams (resistance is a concern)
Macrolides
Fluoroquinolones
What is in a S. pneumoniae vaccine and who should take it
Polysaccharide antigens (capsular) from multiple strains of S. pneumoniae Children get 4 doses in first 15 mo. of life All adults > 65 years old
What is legionella pneumophila
Gm - pleomorphic rod
Obligate aerobe
Fastidious = special conditions for cultivation
Requires cysteine
Where is L. pneumophila found?
It is a parasite of protozoa
Biofilms with protozoa & other bacteria
Thermotolerant (withstands 46C)
Environmental aerosols
L. pneumophila multiplication/spread
Strains multiply within autophagosomes (double membrane of rough ER)
Inflammation -> Acute bronchopneumonia
How does L. pneumophila cause damage?
Cell-mediated immune response
Virulence/proinflammatory mechanisms
Causes cell-mediated immune response
Therapy given for L. pneumophila
Antimicrobial drugs with good intracellular penetration
- Macrolides
- Fluoroquinolones
- Tetracyclines
- NOT PENICILLIN
What are Bordetella pertussis and parapertussis?
Gm - rod
Obligate aerobe
Cause of whooping cough
VERY CONTAGIOUS
Pertussis encounter, entry, spread
Adults are reservoirs
Nasopharynx colonized
Organisms access trachea/bronchi
Ciliary adherence
Damyrsage from pertussis
B. pertussis
- Pertussis toxin
- Adenylate cyclase
- both upregulate host cAMP
- Dec. neutrophil function
- Inc. capillary permeability
- Results in edema
- both upregulate host cAMP
- Endotoxin
B. parapertussis
-NO PERTUSSIS TOXIN
Stages of pertussis
First stage= Catarrhal stage (really runny nose, extremely contagious)
Second stage= Paroxysmal stage (whooping cough, diagnosable via deep nasal swab or nasal flush PCR within 3 weeks of cough onset
Third stage= Convalescent stage (susceptible to other respiratory infections)
Vaccines for pertussis
dTaP - 5 doses <5yrs
Tdap - 11-64 yrs/Lower doses of diptheria & pertussis
What causes kennel cough complex in dogs or immunosuppressed humans?
Bordatella bronchiseptica
Diseases caused by mycobacterium
Tuberculosis
Leprosy
Rapidly growing mycobacteria (RGM)
Properties of mycobacterium
Obligate aerobes
Non-spore formers
Thick, waxy cell wall
Mycolic acid binds carbol fuscin dye (acid fast bacteria)
Stages of mycobacteria infection
Primary stage- Inhalation or ingestion -> localization in intestine or lesion in lung -> Organisms engulfed by macrophages & form granuloma (macrophages surrounded by T cells)
Secondary stage- Granulomas go through a period of latency before becoming activated and disseminating within the lung or intestine
What is M. Leprae?
Granulomatous disease
Prefers lower temp (skin)
Spread via respiratory route
Two forms of disease:
-Tuberculoid leprosy: Milder form of the disease, self limiting, very few bacteria in lesions
- Lepromatous leprosy: Severe & disfiguring, many organisms in lesions, cell mediated immunity significantly decreased
Is M. leprae cultivable?
Uncultivatable in vitro
