Microbial Diseases of the Respiratory System:

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Microbial Diseases of the Respiratory System

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• Lecture 22
• Chapter 24

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Introduction

• Infections of the ______ respiratory system are
  the most common type of infection
• Pathogens that infect any other region of the
  body may use the respiratory system as a _______
  __ __________

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The Upper Respiratory System
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Upper Respiratory Tract Defenses

• Nose hairs filter large particles from entering
  air
• Ciliated mucous membranes of the nose and throat
  trap airborne particles and assist their removal
• Tonsils, adenoids, are lymphatic tissue that
  provide ________ to some infections

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Lower Respiratory Tract Defenses

• The Ciliary Escalator
• Phagocytes in the alveoli
• _____ in the respiratory mucous

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The Lower Respiratory Tract
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Normal Microbiota

• Nasal cavity and throat many microorganisms
  including many potential pathogens
• Lower Respiratory Tract is ________________because
  of the action of the ciliary escalator

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Upper Respiratory Tract Infections

• Pharyngitis inflammation/infection of the
  pharynx region
• Laryngitis same for the larynx
• Tonsillitis, sinusitis, epiglottitis( caused by
  H. influenzae)
• Several bacteria and viruses, often together!
• Most infections are ______ ____________

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Pharyngitis
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Bacterial Diseases of the Upper Respiratory Tract

• Strep Throat Grp. A, beta hemolytic Strep. in
  the pyogenes group, resist ________ and release
  _______
• Droplet transmission ( and in the past
  unpasteurized milk)
• Inflammation of the throat, fever, tonsillitits
  and middle ear infection
• Penicillin
• Immunity is type specific, more than ______ types

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Scarlet Fever

• Caused by an Erythrogenic toxin producing Strep.
  pyogenes which has been _______________ by a
  phage!
• Pink rash, high fever, and enlarged red tongue
• If untreated, skin peels like _________________
  syndrome of
• S. aureus

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Scarlet fever
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Diptheria

• Exotoxin producing Corynebacterium
• Exotoxin inhibits protein synthesis and heart,
  kidney, or nerve damage may result
• Also requires being lysogenized by a phage!
• A ___________ containing fibrin and dead human
  and bacterial cells forms in the throat and
  suffocation can result,also a serious toxin which
  interferes with protein synthesis
• Diptheria comes from the Greek word for _________
• Treatment with antitoxin and antibiotics
• Routine immunization (DPT shots)
• Cutaneous form-slow healing ulcers
• Minimal exotoxin circulation from the cutaneous
  form

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Corynebacterium
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Diptheria membrane
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Middle Ear Infections (Otitis Media)

• Earache occurs as a complication of nose or
  throat infections
• Accumulated pus puts pressure on the ear drum
• Several bacteria can be the cause
• Eardrum can ______ and hearing losses may result
  if repeated
• Treat with antibiotics
• Some babies are prone to repeated infections and
  can have tubes installed to assist with drainage
• 85 of children before the age of 3

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Otitis media
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Viral Diseases of the Upper Respiratory System

• The Common Cold _______ different viruses!
• Sneezing, nasal secretions and congestion
• Complications include
• Lower resp. tract infections
• Laryngitis
• Otitis media
• Sinus infections
• Transmitted by indirect contact! ______ virus on
  the nasal mucosa may be enough!
• Increase during cold weather due to increased
  indoor interpersonal contact, or to physiologic
  changes
• Antibodies are only effective against specific
  strain!

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Lower Respiratory Tract Infections

• Bronchitis and bronchiolitis
• If pulmonary alveoli are involved, pneumonia
• Many of the same microorganisms are involved

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Pertussis ( Whooping Cough)

• Caused by Bordetella pertussis,has a capsule
• First stage resembles a cold and is called the
  _______ stage, tracheal cells are being
  destroyed-toxins
• ________ stage mucous accumulates in the trachea
  and bronchi and causes the deep whooping cough,
  may be so severe as to break ribs! Lasts 1-6
  weeks!
• _______ (third stage) can be very long-up to
  months in length
• Regular immunization of children has decreased
  the incidence

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Bordetella in ciliated cells
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Tuberculosis

• Caused by Mycobacterium tuberculosis
• Slow growing, 20 hour generation time
• 1/3 of the world popn. _____million die per
  year!
• Organism is acid fast and resistant to drying and
  disinfectants
• Alveolar macrophages ingest it and may kill
  (healthy individual) -if dont the bacteria
  multiply in the macrophages
• Tuberculin Skin tests can detect 1. Active
  infections, 2. Prior infection or 3. Vaccination
  and immunity

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Tuberculosis
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Tuberculosis
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Incidence of Tuberculosis
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Tuberculosis

• Caseous lesions are called ____________
• Dead macrophages and bacteria
• May calcify and appear on x-ray as what are
  called _________ complexes
• Lesion liquefies and forms a cavity in which the
  bacteria can grow
• Miliary (millet seed) tuberculosis results when a
  lesion ruptures and bacteria are released into
  the blood or lymph? new foci of infection
• Weight loss, coughing and loss of vigor
  consumption
• Chemotherapy with, us., 2 drugs takes 1-2 years
• Multidrug resistant forms are becoming prevalent
• Blamed on lack of patient compliance

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Mycobacterium in lung
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Stages in tuberculosis
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Stages continued
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Next
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Tuberculin skin test Positive
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TB in the US
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Other Mycobacteria

• M. bovis- cattle ? humans in unpasteurized milk
• Usually affect bones or lymphatic tissue
  (hunchbacked deformation)
• BCG vaccine for tuberculosis consists of live
  __________ M. bovis
• Another Mycobacterium infects patients in late
  stages of _________

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Bacterial Pneumonias

• Typical pneumonias
• H. influenzae or Strep. Pneumonia
• Atypical pneumonias
• Caused by other microorganisms

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Pneumococcal Pneumonia

• Strep. pneumoniae which can generate a capsule
• Vaccine is available, made from capsular
  materials which come from many strains
• Symptoms include fever, breathing difficulty,
  chest pain, rust colored sputum(blood)
• Mortality in the elderly may reach ____
• Penicillin resistant strains up to _____ of
  isolates

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Strep. pneumoniae
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Haemophilus influenzae

• Similar symptoms
• Pre-disposing factors
• Alcoholism
• Poor nutrition, cancer
• Diabetes
• G- coccobacillus
• Cephalosporins are drugs of choice

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Mycoplasma pneumonia

• Endemic, young adults and children
• 3 weeks or longer, fever, cough, headache,
  occasionally severe
• Produces characteristic ______ ____ shaped
  colonies on special enriched agars, but takes ___
  weeks to grow
• Serological tests can identify quickly-before had
  to grow-slow

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Colonies of mycoplasma
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Legionellosis

• 1976-series of deaths of members of American
  Legion182 caught, 29 died
• G- rod Legionella pneumophila
• Grow in water, such as air conditioning cooling
  towers and then be dispersed in air
• Not apparently transmitted from person to person

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Chlamydial Pneumonias

• Psittacosis C. psittaci contaminated bird
  droppings or exudates
• Commercial bird handlers are at risk
• Some suspicion of nervous system involvement
• C. pneumonia
• Type transmitted from person to person
• Suspected association with atheroscelosis!
• Nearly half of population have antibodies

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Other Pneumonias

• Q-fever Coxiella burnetii
• Unpasteurized milk or inhalation of aerosols in
  dairy barns
• Delayed endocarditis (10)
• One microbe can cause infection
• Endemic in Western states
• G pneumonias can be caused by S. aureus and S.
  pyogenes
• G- pneumonias can be caused by M. catarrhalis, K.
  pneumoniae and Pseudomonas sp.

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Viral Diseases of the Lower Respiratory System

• Viral pneumonias
• Usually a complication of something like
  influenza
• Usually not isolated or specifically identified
• Infants get Respiratory Syncytial Virus (RSV)
  infections
• __________ hospiltalized cases per year
• Life threatening in the elderly

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Influenza

• Influenza viruses _________ -_______ die in US
  every year from flu
• Chills, fever, headaches and general body aches
• Different strains are identified by the antigenic
  differences of projections (H and N spikes) on
  the virus
• Antigenic shifts make natural immunity difficult
  and vaccination of less than usual value
• Deaths us. due to secondary infections
• Amantadine-works against Type A influenza virus
  (prophylaxis and cure)

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Influenza Virus
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The Great Flu Pandemic of 1918-1919

• _____ million people died
• Young adults had the highest mortality rates,
  dying _____________________
• Some change in virulence allowed the virus to
  enter the lungs and cause pneumonia and other
  organs as well
• Secondary infections in the pre-antibiotic era
  also took their toll
• Research is underway to try to understand this
  horrific flu, including exhumations of victims
  from frozen Arctic sites

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Summary of Influenza
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Fungal Disease of the Lower Respiratory Tract

• Fungal spores are inhaled all the time and may
  ___________
• Fungal diseases are increasing in general (?)
• Amphotericin B treats the following
• Histoplasmosis usually subclinical, rarely
  progresses to a severe generalized disease

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Fungal Diseases (cont.)

• Coccidiomycosis
• Most cases subclinical, but if weakened by
  fatigue or poor nutrition a disease resembling
  tuberculosis can result
• San Joaquin valley-dust storm!
• Pneumocystis (jiroveci)pneumonia
• P. carnii is found in healthy human lungs
• Causes disease in immunosuppressed patients
• Can be treated with drugs
• Blastomycosis begins in lungs and can spread to
  cause extensive damage
• Mucor, Aspergillus, Rhizopus (common fungi) can
  be come respiratory infections in the
  immunosupressed when large numbers of spores are
  inhaled
• Widespread in decaying vegetation-compost piles

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Pneumocystis in lung
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Summary continued
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Summary
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Summary