Ch 22 Microbial Diseases of the Respiratory System

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Ch 22 Microbial Diseases of the Respiratory System

• Structures
• Normal microbiota
• Upper respiratory system infections
• Bacterial upper respiratory system infections
• Viral upper respiratory system infections
• Lower respiratory system infections
• Bacterial lower respiratory system infections
• Viral lower respiratory system infections
• Fungal lung infections

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Microbial Diseases of the Respiratory System

• Bacterial Diseases (upper)
• Streptococcal respiratory diseases
• Diphtheria
• Sinusitis and otitis media
• Viral Diseases (upper)
• Common cold
• Bacterial Diseases (lower)
• Bacterial pneumonias
• Pneumoncoccal
• Primary atypical (mycoplasmal)
• Klebsiella
• Legionellosis
• Tuberculosis
• Pertussis
• Inhalational anthrax

• Viral Diseases (lower)
• Influenza
• Severe acute respiratory syndrome (SARS)
• Respiratory syncytial virus (RSV)
• Hantavirus pulmonary syndrome (HPS)
• Other viral respiratory diseases
• Fungal Infections (lower)
• Coccidiomycosis
• Blastomycosis
• Histoplasmosis
• Pneumocystis Pneumonia (PCP)

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Structures of the respiratory system
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Structures commonly involved in upper respiratory
infections

• infection
  conjunctivitis
• infection of
  tear ducts dacryocystitis
• infection otitis
  media
• 
  
  infections sinusitis or mastoiditis
• 
  infections pharyngitis
• infection
  epiglottitis

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Structures commonly involved in lower respiratory
infections

• inflammation
  laryngitis
• inflammation
  bronchitis
• infection
  bronchiolitis
• inflammation of
  lungs/ fluid build-up pneumonitis

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Mucociliary Escalator

• Membranes of respiratory system coated with mucus
  
• Mucous membranes composed of ciliated cells
• Cilia propel mucous film away from lungs
• Mucous is swallowed ?

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Normal Flora

• Mastoid air cells, middle ear, sinuses, trachea,
  bronchi, bronchioles and alveoli normally
  _______
• S. aureus carried by 20 of population in ______
  
• streptococci,
  Moraxella, diptheroids, Staphylococcus
• Common pathogenic bacteria in cooler seasons
  Streptococcus pneumoniae, Haemophilus influenzae,
  Neisseria meningitidis

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• Bacterial infections of the respiratory system

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Streptococcal Respiratory Diseases

• Symptoms
• Red throat, often pus and tiny hemorrhages
  enlargement of lymph nodes in neck
• May include abscess formation on tonsils
• Late complications
• Causative agent
• Streptococcus pyogenes
• Pathogenesis
• Virulence associated with inhibition of
  phagocytosis and production of other virulent
  factors
• Attaches to mucous membranes

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Streptococcus pyogenes
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Cell envelope of Streptococcus pyogenes
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Streptococcus pyogenes virulence factors
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Streptococcal Respiratory Diseases

• Epidemiology
• Most cases occur in winter/ spring
• Ingestion of contaminated food
• Prevention and treatment
• Daily penicillin to prevent recurrence in
  patients with rheumatic heat disease
• 10 day penicillin or erythromycin to treat

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The Common Cold

• Symptoms
• Scratchy throat, nasal discharge, malaise,
  headache, cough
• Causative agent(s)
• Rhinoviruses ssRNA
• Coronaviruses ssRNA
• Adenoviruses dsDNA
• Paramyxoviruses ssRNA
• Pathogenesis
• Epidemiology
• Prevention and treatment
• Handwashing avoid people with colds
• Control of symptoms
• No vaccine because of lack of common antigens

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Rhinovirus
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Chest X-ray of Pneumococcal Pneumonia
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Pneumococcal Pneumonia

• Symptoms
• Cough, fever, chill, shortness of breath, chest
  pain
• Causative agent
• 
  capsule bacteria
• stimulates
  endocytosis of bacteria
• lyses host cells,
  suppresses phagosome-lysosome fusion
• Pathogenesis
• Inhalation, colonization of alveoli ?
• Fluid buildup in alveoli
• Epidemiology
• Carriers risk with alcoholism, narcotic use,
  chronic lung disease, viral infections
• Prevention and treatment
• 
  conjugate vaccine for infants
• Treatment with penicillin, erythromycin and others

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Streptococcus pneumoniae
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Primary atypical (Mycoplasmal) pneumonia

• Symptoms
• Gradual onset of cough, fever, malaise, headache,
  sore throat, excessive sweating
• Unproductive cough
• Causative agent
• Pleomorphic, no cell wall
• Capsule, adhesins
• Pathogenesis
• Cells attach to ,
  inhibit
• Epidemiology
• Inhalation of infected droplets, mild infections
  spread disease
• Prevention and treatment
• Treatment with tetracycline or erythromycin
• No vaccine

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Pleomorphic Mycoplasma
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Klebsiella Pneumonia

• Symptoms
• Chills, fever, cough, chest pain and bloody,
  thick, bloody sputum, recurrent chills
• Causative agent
• Gram(-) bacillus
• Capsule
• Pathogenesis
• Aspiration of colonized mucus in throat
• Destruction of
  spread via
• Epidemiology
• at
  higher risk
• Prevention and treatment
• Treatment with cephalosporin and aminoglycoside
• No vaccine

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Klebsiella pneumoniae
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Types of Pnuemonia
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Tuberculosis

• Symptoms
• Chronic fever, weight loss, cough, bloody sputum
• Causative agent
• Slow-growing
• protects
  against lysis following phagocytosis
• 
  antimicrobial drugs, detergents, desiccation
• growth
  of cells in cords
• Pathogenesis
• Inhalation of airborne microorganisms
• 1º tuberculosis, 2º tuberculosis, disseminated
  tuberculosis
• Survive ingestion by alveolar macrophages
• 
  pathogen carried by macrophages to
  bone marrow, spleen, kidneys, CNS

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Primary tuberculosis formation of tubercules