Bacterial upper respiratory infections Flashcards
What tissues of the URT are considered sterile?
- Mastoid air cells2. Middle ear3. Sinuses4. Trachea5. Bronchi and bronchioles6. Alveoli
What URT tissues are colonized by bacteria?
- Nasal cavity2. Nasopharynx3. Pharynx
What are the normal flora of the nose?
- Staph epidermidis2. Staph aureus 3. Corynebacterium spp.
What are features of staph epidermidis and staph aureus?
- Gram positive2. Cocci clusters3. Facultative anaerobes
What are features of corynebacterium spp.?
- Gram positive2. Rod 3. Pleomorphic4. Non spore forming
What are the normal nasopharynx flora?
- Streptococcus2. Viridans strep group 3. Moraxella catarrhalis4. Bacteroides
What are the Viridans strep group pathogens?
- S. mutans 2. S. mitis 3. S. milleri 4. S. salivarius
What are features of the strep pathogens that colonize the nasopharynx?
- Gram positive2. Cocci chains
What are features of the moraxella catarrhalis group?
- Gram negative2. Diploid coccobacillus 3. Aerobic
What are features of the bacteroides group colonizing the nasopharynx?
- Strict anaerobe2. Gram negative3. Bacilli
What URT pathogens of the nasopharynx are associated with seasonal fluctuation?
- Strep pneumoniae 2. Haemophilus influenzae 3. Neisseria meningitidis 4. Moraxella catarrhalis
What are the features of the URT strep pathogens?
- Gram positive2. Cocci in chains 3. Catalase negative
What are the group designations for the URT strep pathogens?
- Group A - S. pyogenes - beta2. Group B - S. agalactiae - beta3. Group D - S. bovis, Enterococcus faecalis4. a hemolytic - S. pneumoniae
What is the causative agent of strep pharyngitis?
Strep pyogenes
What differentiates S. pyogenes from the other throat streptococci?
B hemolytic
What does the Rapid Strep Test target?
Cell wall antigen
What are features of S. pyogenes pathogenicity?
- M protein - antiphagocytic, essential for virulence2. F protein - mediates attachment 3. Capsule - hyaluronic acid, antiphagocytic 4. Strep pyrogenic exotoxins - responsible for severe consequences
What is essential for S. pyogenes virulence?
M protein
What causes Scarlet Fever?
- 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