C-11 Flashcards
What structure separates the upper and lower respiratory tract?
larynx
role of mucus in the innate immune system – what does it contain that helps prevent infection?
defensins - antimicrobial peptides against bacteria, fungi, viruses
lactoferrin - sequesters iron from pathogens
lysozyme - breaks down peptidoglycan
IgA
What microbes are found in the nasal cavity and upper pharynx?
Nasal cavity residents:
* Haemophilus influenzae (G - coccobacilli)
* Staphylococcus aureus (G+ staph)
Upper pharynx residents:
* Streptococcus pyogenes (G+ streptococci)
* Streptococcus pneumoniae (G+ streptococci)
* Veillonella (G- cocci)
* Diphtheroid – Corynebacterium diphtheriae (G+ rods)
* Moraxella catarrhalis (G- diplococci)
Streptococcus pyogenes (upper respiratory tract)
causes: Streptococcal Pharyngitis (Strep Throat), Scarlet fever, Rheumatic fever
gm + streptococci
virulence: capsule, adhesions, exotoxins
transmission: Respiratory droplets / endogenous infection
signs: Sore throat/purulent pockets on tonsils
diagnosis: Rapid strep antigen test
treatment: penicillin
Corynebacterium diphtheria
causes: Diphtheria
gm+ bacilli
virulence: Diphtheria toxin – forms pseudomembrane; adhesins
transmission: Respiratory droplets
signs: Pseudomembrane
diagnosis: Serology/PCR from sputum sample
treatment:
- Vaccine: DTaP
- Antitoxin (IgG), macrolides, penicillin
Streptococcus pneumonia (upper and lower tract)
causes: Otitis Media and
Rhinosinusitis (upper); Pneumococcal pneumonia (lower)
gm+ diplococci
virulence: Capsule; Pneumolyisn – kills ciliated cells; adhesins
transmission: Respiratory droplets – carriers / endogenous infection
signs: Ear pain/sinus pressure
diagnosis: Sputum sample culture/urine antigen test
treatment: Vaccine: PPSV23; Flu vaccine helps reduce incidence; Penicillin/amoxicillin
Haemophilus influenzae
causes: Rhinosinusitis, otitis media
gm- coccobacilli
virulence: Capsule; adhesins
transmission: Respiratory droplets / endogenous infection
signs: Ear pain/sinus pressure
diagnosis: Serological test
treatment: Amoxicillin; Flu vaccine helps reduce incidence
Describe how the mucociliary escalator works to prevent lower RT infection
Ciliated mucous membrane lines trachea, bronchi, and
bronchioles, which carry mucus and contaminants up the pharynx to be swallowed and destroyed in the stomach
Explain why there is largely not a lower respiratory tract microbiome
LRT thought to be largely sterile: contains very few microbes; many are transients from the URT; Microbes that successfully colonize the LRT must be small enough to get past or make virulence factors that disable the mucus escalator
Pneumonia
inflammation of the lungs in which the alveoli and bronchioles are filled with fluid
Bordetella pertussis
causes: Pertussis (whooping
cough)
gm- bacilli
virulence:
- Pertussis toxin/Adenylate cyclase toxin – increase mucus
- Dermonecrotic toxin – kills cells
- Tracheal toxin – paralyzes cilia
- adhesins
transmission: Respiratory droplets – carriers
signs: “whooping” vigorous cough
diagnosis: Sputum sample culture
treatment:
- Vaccine: DTaP
- Erythromycin to reduce
transmission/supportive care
Streptococcus pneumoniae
causes: Pneumococcal pneumonia
gm+ diplococci
virulence:
- Capsule
- Pneumolyisn – kills ciliated cells
- adhesin
transmission: Respiratory droplets – carriers
signs: (overall pneumonia signs?)
diagnosis: Sputum sample culture/urine antigen test
treatment: Vaccine: PPSV23; Penicillin or vancomycin
Mycoplasma pneumoniae – Mycoplasma “walking” pneumonia
causes: Mycoplasmal/primary
atypical pneumonia
Pleomorphic / no cell wall
virulence: Capsule; adhesins
transmission: Respiratory droplets
signs: Persistent signs/symptoms
diagnosis: Sputum sample serology/PCR
treatment: Macrolides, doxycycline, or floroquinolones
Klebsiella pneumoniae
causes: klebsiella - Hospital-acquired pneumonia
gm- bacilli
virulence: Capsule; adhesins;
endotoxin
transmission: Not through air;
from poor hand hygiene/aseptic
signs: currant-jelly sputum
diagnosis: Sputum sample
culture
treatment: Cephalosporins, supportive care
Legionella pneumophila
causes: Legionnaire’s disease/ Legionellosis
gm- bacilli
virulence: Intracellular – heat
tolerant; adhesins
transmission: Not P2P; shower
heads, hot tubs
signs: (overall pneumonia signs?)
diagnosis: Urine antigen test
treatment: Doxycycline, azithromycin, quinolones
