Glossary of CHAPTER 24- Microbial Diseases of the Respiratory System
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- Anatomical defenses of Upper Respiratory System?
- course hairs, mucus secreting cells, cilia, tonsils - lymphoid tissue
- Laryngitis and tonsillitis caused by?
- Streptococcus pneumoniae, Streptococcus pyogenes,viruses - can often work in combination - usually self-limiting (i.e., recovery will usually occur without medical intervention)
- Epiglottitis caused by?
- Haemophillus influenzae - most threatening disease of the URS, Hib vaccine has significantly reduced the number of cases
- Strep throat caused by?
- Streptococcus pyogenes - group A beta-hemolytic
Resistant to phagocytosis
Streptokinases lyse clots
Streptolysins are cytotoxic
Diagnosis by indirect agglutination - uses latex particles coated with antibodies against group A streptococci
- Scarlet Fever caused by?
- Streptococcus pyogenes
Erythrogenic toxin produced by lysogenized S. pyogenes - reddening toxin causes red skin rash and high fever
- Diptheria caused by:
- Corynebacterium diptheriae; gram postive rod
- Diphtheria was the leading infectious killer of children until?
- Leading infectious killer of children until 1935
- What has a membrane that can block the air passage?
- Diphtheria membrane of fibrin, dead tissue, and bacteria - can totally block air passage
- Diphtheria toxin produced by? and the toxin does what?
- Diphtheria toxin produced by lysogenized C. diphtheriae - toxin interferes in protein synthesis
- Diptheria prevented by?
- Prevented by DTaP and Td vaccine (Diphtheria toxoid, inactivated toxin that elicits an immune response)
Effective treatment requires antibiotics and antitoxin
- Cutaneous diphtheria:
- Infected skin wound leads to slow healing ulcer
- Otitis Media:
- Infections of the middle ear - account for nearly one half of office visits to pediatricians, affects 85% of children before the age of three
- Causes and percentages of Otitis Media?
- S. pneumoniae (35%)
H. influenzae (20-30%)
M. catarrhalis (10-15%)
S. pyogenes (8-10%)
S. aureus (1-2%)
- Otitis Media is treated with?
- Treated with broad-spectrum antibiotics
Incidence of S. pneumoniae reduced by vaccine
- The Common Cold:
- Viral disease of the URS; most prevalent disease of humans in the temperate zones (kids: 6-8 colds/year, and adults: 2-4 colds/yr)
- What causes the common cold?
- More than 200 agents cause the common cold
Rhinoviruses (50%) - at least 113 serotypes
A single virus particle can cause a cold
Almost all Rhinoviruses attached to ICAN-1 on nasal mucosa of host cells - possible mechanism for control
- Lower respiratory system?
- Larynx, trachea, bronchial tubes, alveoli
The ciliary escalator keeps the lower respiratory system sterile
Aveolar macrophages - destroy microorganisms that reach the lung
- Bacteria, viruses, & fungi cause in the Lower Respiratory System:
- Bacteria, viruses, & fungi cause:
- Pertussis (whooping cough) caused by?
- Bordatella pertussis: gram neg. coccobacillus, capsulated
Attach to ciliated cells in the trachea
Tracheal cytotoxin of cell wall damages ciliated cells
Pertussis toxin - enters bloodstream, causese symptoms of disease
- Pertussis prevented by?
- Prevented by DTaP vaccine (acellular Pertussis cell fragments)
- Pertussis' 3 stages?
- Stage 1: Catarrhal stage: like common cold
Stage 2: Paroxysmal stage: Violent coughing sieges
Stage 3: Convalescence stage: may last for months
- Tuberculosis caused by:
- Mycobacterium tuberculosis: acid-fast rod that is transmitted from human to human.
- Mycobacterium Tuberculosis generation time?
- >20 hours
- M. bovis:
- M. bovis: <1% U.S. cases, not transmitted from human to human
- M. avium-intracellulare:
- M. avium-intracellulare - infects people with late stage HIV infection
- Stages of Tuberculosis:
- 1. bacilli is inhaled and reach the alveoli of the lung
2. ingested by a macrophage but survives
3. bacilli multiply in macrophages and cause a chemotactic response (start of tubercule)
4. after a few weeks, disease symptoms appear as many macrophages die, releaseing tubercule bacilli and forming a caseous center in the tubercule.
5. liquefication=caseous center enlarges and forms tuberculous cavity
6. tubercule ruptures and bacilli spill into bronchioles and diseminate throughout the lung, circulatory, and lymphatic systems.
- Treatment of Tuberculosis:
- Prolonged treatment with multiple antibiotics - bacilli are slow growing and may be hidden in macrophages or locations difficult to reach with antibiotics
Vaccines: BCG, live, avirulent M. bovis. Not widely used in U.S
- Diagnosis of Tuberculosis
- Diagnosis: Tuberculin skin test screening
+ = current or previous infection
Followed by X-ray, acid-fast staining of sputum, culturing bacteria
- Pneumococcal Pneumonia caused by:
- Streptococcus pneumoniae: Gram-positive encapsulated diplococci
Most common - typical pneumonia
- Diagnosis and Treatment of Pneumococcal Pneumonia?
- Diagnosis by culturing bacteria
Penicillin is drug of choice - antibiotic resistance is becoming a problem
- Haemophilus influenzae Pneumonia? Predisposing factors?
- Gram-negative coccobacillus
Alcoholism, poor nutrition, cancer, or diabetes are predisposing factors
- Haemophilus influenzae Pneumonia treatment?
- Second-generation cephalosporins = drugs of choice
- Mycoplasmal Pneumonia caused by?
- Mycoplasma pneumoniae: pleomorphic, wall-less bacteria
- Mycoplasmal Pneumonia also called?
- Also called primary atypical pneumonia and walking pneumonia
- Mycoplasmal Pneumonia common in what age group? and how do you diagnose?
- Common in children and young adults
Diagnosis by PCR or by IgM antibodies
- Legionellosis caused by?
- Legionella pneumophila: Gram-negative rod
- L. pneumophila found where? and how is it trasmitted?
- L. pneumophila is found in water
Transmitted by inhaling aerosols, not transmitted from human to human
- Diagnosis and Treatment of Legionellosis?
- Diagnosis: culturing bacteria
- Psittacosis (Ornithosis) caused by?
- Chlamydia psittaci: gram-negative intracellular bacterium associated with birds such as parakeets and parrots
- Psittacosis (Ornithosis) transmitted by?
- Transmitted by elementary bodies from bird dropping to humans
- What reorganizes into reticulate body after being phagocytized?
- Psittacosis (Ornithosis)
- Diagnosis and Treatment of Psittacosis (Ornithosis)?
- Diagnosis: culturing bacteria in eggs or cell culture
- Chlamydial Pneumonia caused by?
- Chlamydia pneumoniae
Resembles mycoplasmal pneumonia
Transmitted from human to human
- Chlamydial Pneumonia transmitted by?
- Transmitted from human to human
- Diagnosis and Treatment of Chlamydial Pneumonia?
- Diagnosis by FA test
- Q fever caused by? transmitted by? Who is most at risk?
- Coxiella burnetti: obligate, intracellular bacterium
Can survive airbourne transmission(has an endospore like body)
Inhaling a single pathogen can cause infection
Workers in dairy and meat processing plants are most at risk
- Viral Pneumonia (LRS)?
- can occur as a complication of influenza, measles, chickenpox
Viral etiology suspected if no cause determined
- Respiratory Synctial Virus (RSV)?
- Common in infants; 4500 deaths annually
Causes cell fusion (syncytium) in cell culture
Symptoms: coughing and wheezing
Diagnosis by serologic test for viruses and antibodies
- Influenza symptoms and mortality?
- Chills, fever, headache, muscle aches (no intestinal symptoms)
1% mortality due to secondary bacterial infections
- Treatment of Influenza?
- Treatment: Amantadine
Vaccine for high-risk individuals
- Structure of Influenza Virus:
- 8 separate RNA segments of different lengths
enclosed by inner layer of protein (capsid)
outer lipid bilayer-which contains H and N spikes
- H spikes:
- Hemagglutinin (H) spikes used for attachment to host cells
- N spikes:
- Neuraminidase (N) spikes used to release virus from cell
- Antigenic shift:
- Changes in H and N spikes
Probably due to genetic recombination between different strains infecting the same cell
- Antigenic drift:
- Mutations in genes encoding H or N spikes
May involve only 1 amino acid
Allows virus to avoid mucosal IgA antibodies
- Influenza serotypes:
- A: causes most epidemics, Antigenic subtypes = H3N2, H1N1, H2N2
B: moderate, local outbreaks
C: mild disease
- Histoplasmosis caused by? transmitted by?
- Histoplasma capsulatum; dimorphic fungus
Transmitted by airborne conidia from soil - >75% of population in affected areas have antibodies
- Diagnosis and Treatment of Histoplasmosis?
- Diagnosis by culturing fungus
Treatment: amphotericin B
- Coccidioidomycosis caused by? and Life cycle?
- Cocciodioides immitis
arthrospore grows into tubular hypha --> hypha segments into arthrospores-->arthrospores inhaled -->inhaled arthrospore (how they are transmitted) grows into spherule-->endopores grown inside spherule-->spherule releases endospores
- Diagnosis and Treatment of Coccidioidomycosis?
- Diagnosis by serological tests or DNA probe
Treatment: amphotericin B
- Pneumocystis Pneumonia caused by?
- Pneumocystis jiroveci (P. carinii) found in healthy human lungs (once thought to be a protozoan but now identified as a fungus)
- Pneumocystis Pneumonia occurs in?
- Pneumonia occurs in newly infected infants & immunosuppressed individuals (had become a primary indicator of AIDS)
- Pneumocystis Pneumonia treated by?
- Treatment: Timethoprim-sulfamethoxazole
- Pneumocystis life cycle:
- Mature cyst contains intracystic bodies-->cyst ruptures releasing bodies-->bodies develop into trophozites-->trophozites divide-->trophozites develop into a cyst.
- Blastomycosis caused by?
- Blastomyces dermatitidis, dimorphic fungus
Found in soil
- Blastomycosis causes? treatment?
- Can cause extensive tissue destruction
Treatment: amphotericin B
- Opportunistic fungi involved in respiratory disease:
- What requires both antibiotics and an antitoxin?