Bacterial upper respiratory infections Flashcards
1
Q
What tissues of the URT are considered sterile?
A
- Mastoid air cells2. Middle ear3. Sinuses4. Trachea5. Bronchi and bronchioles6. Alveoli
2
Q
What URT tissues are colonized by bacteria?
A
- Nasal cavity2. Nasopharynx3. Pharynx
3
Q
What are the normal flora of the nose?
A
- Staph epidermidis2. Staph aureus 3. Corynebacterium spp.
4
Q
What are features of staph epidermidis and staph aureus?
A
- Gram positive2. Cocci clusters3. Facultative anaerobes
5
Q
What are features of corynebacterium spp.?
A
- Gram positive2. Rod 3. Pleomorphic4. Non spore forming
6
Q
What are the normal nasopharynx flora?
A
- Streptococcus2. Viridans strep group 3. Moraxella catarrhalis4. Bacteroides
7
Q
What are the Viridans strep group pathogens?
A
- S. mutans 2. S. mitis 3. S. milleri 4. S. salivarius
8
Q
What are features of the strep pathogens that colonize the nasopharynx?
A
- Gram positive2. Cocci chains
9
Q
What are features of the moraxella catarrhalis group?
A
- Gram negative2. Diploid coccobacillus 3. Aerobic
10
Q
What are features of the bacteroides group colonizing the nasopharynx?
A
- Strict anaerobe2. Gram negative3. Bacilli
11
Q
What URT pathogens of the nasopharynx are associated with seasonal fluctuation?
A
- Strep pneumoniae 2. Haemophilus influenzae 3. Neisseria meningitidis 4. Moraxella catarrhalis
12
Q
What are the features of the URT strep pathogens?
A
- Gram positive2. Cocci in chains 3. Catalase negative
13
Q
What are the group designations for the URT strep pathogens?
A
- Group A - S. pyogenes - beta2. Group B - S. agalactiae - beta3. Group D - S. bovis, Enterococcus faecalis4. a hemolytic - S. pneumoniae
14
Q
What is the causative agent of strep pharyngitis?
A
Strep pyogenes
15
Q
What differentiates S. pyogenes from the other throat streptococci?
A
B hemolytic
16
Q
What does the Rapid Strep Test target?
A
Cell wall antigen
17
Q
What are features of S. pyogenes pathogenicity?
A
- M protein - antiphagocytic, essential for virulence2. F protein - mediates attachment 3. Capsule - hyaluronic acid, antiphagocytic 4. Strep pyrogenic exotoxins - responsible for severe consequences
18
Q
What is essential for S. pyogenes virulence?
A
M protein
19
Q
What causes Scarlet Fever?
A
- Occurs during acute illness of S. pyogenes2. Erythrogenic toxin (one of SPEs) is released from infection site and enters blood stream 3. Redness of skin and white coating on tongue
20
Q
What is the cause of rheumatic fever?
A
- Due to an acute inflammatory process 2. Stems from throat S. pyogenes infection 3. Autoimmune cross reaction with host tissues
21
Q
What is the cause of toxic shock syndrome?
A
- May begin at site of any Group A disease2. Usually skin and soft tissue 3. Nausea, vomiting, diarrhea, hypotension shock and organ failure
22
Q
What is the cause of necrotizing fasciitis?
A
SPE release
23
Q
What are post streptococcal infection sequelae?
A
- Acute glomerulonephritis 2. Deposition of antigen-antibody complexes in glomeruli3. Edema, hypertension, hematuria, proteinuria, decreased serum complement levels
24
Q
What group is S. pyogenes in?
A
A
25
What is the causative agent of diptheria?
Corynebacterium diptheriae
26
What are the features of corynebacterium diptheriae?
1. Variable shape2. Nonmotile3. Non spore forming4. Gram positive5. Rod ("Chinese letters")
27
What is the diptheria virulence factor?
1. Diptheria toxin 2. Strain must be lysogenized by a bacteriophage to gain toxin producing capability
28
What are the symptoms of diptheria?
1. Begins with mild sore throat, slight fever, high fatigue and malaise2. Neck swelling is dramatic3. Whitish gray membrane forms on tonsils and throat or in nasal cavity 4. Heart and kidney failure, paralysis can rapidly follow
29
What is the mechanism of diptheria toxin infection?
1. A and B subunit on toxin 2. B binds3. A inactviates EF-2 - halts protein synthesis and induces cell death
30
What are the two main causative agents of pinkeye?
1. Haemophilus influenzae - gram negative rod2. Streptococcus pneumoniae - pneumococcus
31
What are the main causative agents of otitis media / sinusitis?
1. Haemophilus influenzae - gram negative rod2. Streptococcus pneumoniae - pneumococcus
32
Haemophilus influenzae and streptococcus pneumoniae otitis media infections are generally responsive to what antibiotic therapy?
Ampicillin
33
What are the features of Haemophilus influenzae?
1. Small, pleomorphic 2. Gram negative3. Rods or coccobacilli 4. Facultative anaerobes, fermentative
34
What is the main virulence factor in H. influenzae?
Antiphagocytic polysaccharide capsule
35
What is the treatment for H. influenzae?
Broad spectrum cephalosporins
36
What are the properties of chlamydia bacteria?
1. Inner and outer membranes similar to gram negative 2. Contain both DNA and RNA 3. Prokaryotic ribosomes 4. Synthesize their own proteins, nucleic acids, lipids 5. Can form different developmental forms - elementary bodies and reticulate bodies
37
What are the properties of the two chlamydia infection forms?
1. Elementary bodies - metabolically inactive, infectious 2. Reticulate bodies - metabolically active, noninfectious
38
Chlamydia trachomatis is responsible for what diseases?
1. Trachoma2. Adult inclusion conjunctivitis3. Neonatal conjunctivitis 4. Infant pneumonia5. UG infections
39
What is the pathogenesis of chlamydia infections?
1. Direct destruction of host cells during replication 2. Host inflammatory response further exacerbates
40
What are the immunological properties of chlamydia?
1. Does not confer long lasting immunity 2. Reinfection usually induces a vigorous damaging inflammatory response
41
What is the virulence of chlamydia?
Intracellular replication / prevention of phagolysosome formation
42
What are features of trachoma?
1. Follicular conjunctivitis with diffuse inflammation 2. Eyelids can turn inward due to scarring 3. Corneal abrasion and scarring
43
What are features of adult inclusion conjunctivitis?
1. Acute follicular conjunctivitis 2. Mucopurulent discharge, keratitis, corneal infiltrates, some vascularization
44
What are features of neonatal conjunctivitis?
1. Infants exposed to C. trachomatis at birth 2. Conjunctival scarring and corneal vascularization occur
45
What are features of infant pneumonia?
1. Onset 2-3 weeks after birth 2. Bronchitis with a dry cough, afebrile
46
How is C. trachomatis be diagnosed?
1. Cytologic, serologic, culture findings2. Direct detection of C. trachomatis antigen in clinical specimen3. C. trachomatis through use of molecular probes
47
Chlamydophila pneumoniae is an important cause of what conditions?
1. Pneumonia2. Bronchitis3. Sinusitis
48
What are features of Chlamydophila pneumoniae infections?
1. Most severe infections involve only one lung2. Cannot be distinguished from other pneumonias 3. Could be involved in atherosclerosis
49
What are features of Chlamydophila psittaci?
1. Parrot fever2. Present in blood, tissue, feces, feathers of infected birds 3. Infection via respiratory tract 4. Spreads to reticuloendothelial cells of liver and spleen 5. Causes focal necrosis, then spreads6. Result is lymphocytic inflammatory response on the alveolar and interstitial spaces
