Respiratory Microbiology (FREITAS) Flashcards
Understand the main defenses of the respiratory system, location and main function:
Mucociliary system: upper respiratory tract
- Function: mucus secretion and mucociliary clearance mechanism
- Includes, nasal vibrissae, action of cilia and mucous glands and globlet cells
Cough reflex: Upper respiratory tract
- Function: enhances clearance of secretions and particulates from the airways and protects from aspiration of foreign materials
Mucosal antibody: Upper respiratory tract
- Function: neutralize almost any pathogen or toxin trying to contact epithelial cells
- Mainly secretory IgA
Bronchoconstriction: Lower respiratory tract
- Function: restricts the amount of air passing into the lungs
Other Defenses: Upper and Lower respiratory tracts
- Function: kill foreign pathogens
- Includes: lactoferrin, lysozymes and a-antitrypsin
All of the following are Upper respiratory tract defenses EXCEPT:
A. Mucociliary system
B. Cough reflex
C. Mucosal antibody
D. Bronchoconstriction
E. All of the above are upper respiratory tract defenses
D. Bronchoconstriction
Upper respiratory tract:
- Mucociliary system
- Cough reflex
- Mucosal antibody
Lower respiratory tract:
- Bronchoconstriction
______ enhances clearance of secretions and particulates from the airways and protects from aspiration of foreign materials.
A. Mucociliary system
B. Cough reflex
C. Mucosal antibody
D. Bronchoconstriction
E. None of the above
B. Cough reflex
_________ neutralizes almost any pathogen or toxin trying to contact epithelial cells.
A. Mucociliary system
B. Cough reflex
C. Mucosal antibody
D. Bronchoconstriction
E. None of the above
C. Mucosal antibody
_______ retricts the amount of air passing into the lungs.
A. Mucociliary system
B. Cough reflex
C. Mucosal antibody
D. Bronchoconstriction
E. None of the above
D. Bronchoconstriction
Which of the following functions in mucus secretion?
A. Mucociliary system
B. Cough reflex
C. Mucosal antibody
D. Bronchoconstriction
E. None of the above
A. Mucociliary system
All of the following are other defenses that are located in the upper and lower respiratory tracts EXCEPT:
A. Secretory IgA
B. Lactoferrin
C. Lysozymes
D. a-antitrypsin
A. Secretory IgA
Mucosal antibody = IgA = upper respiratory tract
Other defenses = lactoferrin, lysozymes, a-antitrypsin = upper and lower respiratory tracts
Virulent respiratory pathogens successfully evade the epithelial defenses by specifically __________.
Virulent respiratory pathogens successfully evade the epithelial defenses by specifically adhering to respiratory epithelium.
Discuss the Sore Throat Syndrome:
- What microorganism is associated with sore throat syndrome?
- What are the 6 virulence factors of this microorganism?
Sore Throat Syndrome
- Streptococcus Pyogenes
- Virulence factors:
- Protein M
- streptokinase
- hyaluronidase
- DNAse
- capsule
- streptolysin O
What are the 4 complications associated with Sore Throat Syndrome?
1. Peritonsillar abscess: tonsillar sepsis, inflammation fo the throat (quinsy throat)
2. Sinusitis: condition where the paranasal sinuses fill w/ exudate
3. Otitis media: infection of the iddle ear; common in children
4. Scarlet fever: diffuse erythematous rash beginning on the chest and spreading to the extremities; complication of streptococcal pharyngitis (S. pyogenes) - strawberry tongue
Discuss Rheumatic fever:
- What microorganism triggers rheumatic fever?
- What is the pathogenesis of this microorganism?
- What are the 4 affected sites?
- Laboratory diagnosis:
Rheumatic Fever
- Streptococcus pyogenes
- Pathogenesis:
- Autoimmunity- cross-reactivity (S. pyogenes share the same antigens as heart valves)
- Hypersensitivity type III (antibody-antigen complexes)
- Affected sites:
- heart
- kidney
- joints and blood vessels
- Laboratory diagnosis:
- Throat swabs consisting of beta-hemolytic colonies
- Evidence for antibody to streptolysin O - produced by S. pyogenes
S. pyogenes is _______.
A. alpha-hemolytic
B. beta-hemolytic
C. gamma-hemolytic
D. None of the above
B. beta-hemolytic
beta-hemolytic: complete destruction of RBCs?
What are the two main virulence factors of S. pyogenes?
S. Pyogenes = Protein M and Streptolysin O
How can Rheumatic Fever be detected in the lab?
Clinical: throat swabs exhibiting beta-hemolytic colonies
Serological evidence: antibody to streptolysin O (produced by S. pyogenes)
Discuss Diphtheria:
- What is the main associated microorganism?
- _______ tends to be mild, but the infected discharge is important in the spread of disease among children.
- Pathogenesis:
- ______ inhibits protein synthesis
- Obstruction of _____ and ______
Diphtheria
- Associated microorganism = Corynebacterium diphtheriae
- Nasal diphtheria tends to be mild, but the infected discharge is important in the spread of disease among children
- Pathogenesis:
- Diphtheria toxin - inhibits protein synthesis
- Obstruction of airways and pharyngeal diphtheria
Discuss Vincent’s angina:
- Predisposing factors?
- Microorganisms?
- Clinical features?
Vincent’s angina
Predisposing factors: poor dental health and poor oral hygiene, recurring periodontal disease, advance age, smoking or chewing tobacco and immunodeficiency
Microorganism: Borrelia vincenti in association w/ fusiform bacilli
Clinical features: soreness of mouth and gums (painful gingiva), halitosis, bleeding gums
- Progression: periodontium might be destroyed (ANUG)
- Involves all gingival margin which become covered by a necrotic pseudo membrane
Discuss Ludwig’s angina:
- Originates from?
- Predisposing factors?
- Associated microorganisms?
- Clinical features?
Ludwig’s angina
Originates from an odontogenic infection (tooth abscess), especially from the 2nd or 3rd lower molars
Predisposing factors: dental caries, recent dental tx, systemic illnesses, alcoholism, AIDS, jawbone fracture, oral piercings
Associated microorganisms: S. viridans and S. aureus
Clinical features: tooth pain, fever, difficulty in swallowing and increasing stridor
- examination shows a bull-neck appearance w/ tenderness of the neck and throat
Poor oral hygiene, recurring periodontal disease, advanced age, smoking or chewing tobacco and immunodeficiency are predisposing factors of which of the following?
A. Vincent’s angina
B. Ludwig’s angina
A. Vincent’s angina
Which of the following is associated w/ Fusiform bacilli?
A. Diphtheria
B. Vincent’s angina
C. Ludwig’s angina
B. Vincent’s angina
Vincent’s angina = Borrelia vincenti + Fusiform bacilli
Ludwig’s angina = S. Viridans + S. aureus
Which of the following is associated w/ S. viridans and S. aureus?
A. Diphtheria
B. Vincent’s angina
C. Ludwig’s angina
C. Ludwig’s angina
Vincent’s angina = Borrelia vincenti + Fusiform bacilli
Ludwig’s angina = S. Viridans + S. aureus
Dental caries, recent dental tx, systemic illness, alcoholism, AIDS, jawbone fracture and oral piercings are predisposing factors of which of the following?
A. Vincent’s angina
B. Ludwig’s angina
B. Ludwig’s angina
Vincent’s angina = poor oral health and recurring periodontal disease
Ludwig’s angina = dental caries, recent dental tx
Which of the following is associated with ANUG?
A. Vincent’s angina
B. Ludwig’s angina
A. Vincent’s angina
Discuss the Common Cold Syndrome:
- Associated viruses?
- Effect in the oral cavity?
Common Cold Syndrome
Associated viruses: Rhinoviruses
Effect in the oral cavity: sinus pressure can hurt teeth and cause xerostomia
Discuss Infectious mononuleosis “Mono”:
- Associated virus?
- Symptoms?
Infectious Mononucleosis
Associated virus = Epstein-Barr virus (EBV)
Symptoms: fever, sore throat and swollen lymph nodes and abnormal lymphocytes in blood. Tonsillitis and fatigue are common. Splenomegaly
Discuss Enteroviral pharyngitis:
- Associated virus?
- What are the 3 examples of enteroviral pharyngitis and common pathologies?
Enteroviral pharyngitis
Associated virus: Enteroviruses (coxsackievirus or echovirus)
Examples of enteroviral pharyngitis and common pathologies:
- Herpangina = coxsackievirus type A 2-6
- Acute lymphonodular pharyngitis = coxsackievirus type A10
- Hand-foot and mouth disease = coxsackievirus A5, 9, 10 and 16
(T/F)
The normal upper respiratory tract is bacteriologically sterile.
FALSE
correct statement: The normal lower respiratory tract is bacteriologically sterile
Discuss Bronchitis:
- Associated microorganisms?
- Acute bronchitis vs Chronic bronchitis:
Bronchitis
Associated microorganisms: influenza and parainfluenza
- bacterial infection is secondary after viral
Acute bronchitis: shorter illness that commonly follows a cod or viral infection (Flu)
Chronic bronchitis: a persistent productive cough for at least 3 consecutive months in at least 2 consecutive years
- common among cigarette smokers
- progress to COPD
Discuss Chronic Obstructive Pulmonary Disease (COPD):
- Associated microorganisms?
- Symptoms?
- Pathogenesis?
- Diagnosis?
COPD
Associated microorganisms: S. pneumonie, H. influenza, Chlamydia pnemonie, Mycoplasma pneumonie
Symptoms: excessive mucus production and poor clearance of bronchi
Pathogenesis: emphysema and chronic bronchitis
Diagnosis: sputum is always colonized with mixed upper respiratory tract flora and may contain neutrophils
Discuss Cystic Fibrosis:
- Associated microorganisms?
- Characteristics?
- Oral cavity manifestation?
Cystic Fibrosis
Associated microorganisms: S. aureus, S. pneumoniae, Hemophilus influenzae, Pseudomonas aeruginosa
Characteristics: thick mucus that blocks the respiratory ‘tubes’ and traps microorganisms
Oral cavity manifestations: possible enamel defect due to antibiotic use
Discuss Pertussis (whooping cough):
- Associated microorganism?
- Who is most commonly affected?
- What are the 3 stages?
- Pathogenesis?
Pertussis (whooping cough)
Associated microorganism: Bordetella pertussis
- Affects infants
Stages:
- Catarrhalis stage
- Paroxysmal stage
- Convalescent stage
Pathogenesis:
- colonizing of the bronchial epithelium and decrease phagocytic killing
- The toxin porduced by B. pertussis paralyzes the cilia, thus impairing an important pulmonary defense
Discuss Pneumonia:
- Infection in one or both lungs, characterized by _______ of the alveoli in the lungs.
- Transmission?
- Bacterial pneumonia vs Viral pneumonia:
Pneumonia
- Infection in one or both lungs, characterized by inflammatioin of the alveoli in the lungs
- Transmission: droplets
Bacterial pneumonia:
- S. pneumonia, S. aureus, H. influenza, Legionella pneumophilia and MRSA
Viral pneumonia:
- Coronavirus, influenza A and B, Rhinovirus, Adenovirus and Respiratory syncytial virus
What are the 5 bacteria associated with bacterial pneumonia?
- S. pneumonia
- S. aureus
- H. influenza
- Legionella pneumophilia
- MRSA (methicillin resistant S. aureus)
What are the 5 viruses associated with Viral pneumonia?
- Coronaviruses (MERS-CoV and SARS)
- Influenza A and B
- Rhinovirus
- Adenovirus
- Respiratory syncytial virus
Do you expect to find bacteria or any type of microorganisms in the lower respiratory tract?
NO
Possible enamel defect due to antibiotic use is an oral manifestation of which of the following?
A. Bronchitis
B. Cystic fibrosis
C. Pertussis
D. Pneumonia
B. Cystic fibrosis
Discuss Severe Acute Respiratory Syndrome (SARS):
- Associated microorganism?
- Pathogenesis?
SARS
Associated microorganism: SARS coronavirus
Pathogenesis: virus spreads by the airborne route through droplets or aerosols. Infectivity of the virus is high during the febrile period
Discuss Croup (laryngotracheobronchitis):
- Associated microorganism:
- Symptoms?
- Pathogenesis?
- Who is it common in?
Croup
Associated microorganism: parainfluenza viruses type 1 and 2
Symptoms: harsh barking coughs, noisy breathing, restlessness and tachycardia increase as respiratory obstruction develops
Pathogenesis: the virus invades epithelial cells of the tracheobronchial tree, via the binding of haemagglutinin and neuraminidase
- Common in infants
Discuss Influenza:
- Associated microorganisms?
- which one ONLY infects humans?
- which one infects humans and animals?
- Pathogenesis?
- Symptoms?
Influenza:
Associated microorganisms: influenza viruses type A and B
- Influenza type B = ONLY humans
- Influenza type A = humans and animals
- type A is the major cause of pandemic and epidemic influenza infections
Pathogenesis: direct person-to-person spread through acute infections
- viruses favor bacteria colonization in the lung by acting on the epithelial cells of the upper respiratory tract:
- removing the physical barrier which opposes the lung bacterial colonization and reducing the ciliary mucus clearance
Symptoms: tracheobronchitis w/ some involvement of small airways
What two diseases do not yet have a vaccine available for?
Common cold (Rhinovirus) and SARS (Coronavirus)
(T/F)
Periodontal bacteria may potentially disseminate into the lower respiratory tract causing infections.
True
What are the 3 possible mechanisms of oral bacteria to promote respiratory infections?
1. Aspiration of oral bacteria or pathogen into the lungs (anaerobic bacteria in sputum)
2. Periodontal disease associated bacterial enzymes: enzymes in saliva may alter mucosal surfaces to promote colonization and adhesion of respiratory pathogens
3. Cytokines released at the oral cavity during inflammatory response: mediated alteration in respiratory epithelium
What are the 5 pathogens associated to periodontal disease that may be found in infected lung fluids?
- Which of these 5 pathogens may participate in initiation or progression of pneumonia?
- P. gingivalis
- Actinobacillus actinomycetemocomitans
- Actinomyces
- Fusobacterium nucleatum
- S. viridans may participate in initiation or progression of pneumonia
