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24_Microbial_Diseases_of_the_Respiratory_System (2).ppt
- 1. Medical Technology Department, Faculty of Science, Islamic University-Gaza MICROBIOLOGY Dr. Abdelraouf A. Elmanama Ph. D Microbiology 2008 Chapter 24 Microbial Diseases of the Respiratory System
- 2. 2008 Microbial Diseases of the Upper Respiratory System • Laryngitis: S. pneumoniae, S. pyogenes, viruses • Tonsillitis: S. pneumoniae, S. pyogenes, viruses • Sinusitis: Bacteria • Epiglottitis: H. influenzae
- 3. 2008 • Upper respiratory normal microbiota may include pathogens Upper Respiratory System Figure 24.1
- 4. 2008 Streptococcal pharyngitis (Strep throat) Figure 24.3 • Streptococcus pyogenes • Resistant to phagocytosis • Streptokinases lyse clots • Streptolysins are cytotoxic • Diagnosis by indirect agglutination
- 5. 2008 • Streptococcus pyogenes • Pharyngitis • Erythrogenic toxin produced by lysogenized S. pyogenes Scarlet Fever Figure 24.4
- 6. 2008 • Corynebacterium diphtheriae: Gram-positive rod • Diphtheria membrane of fibrin, dead tissue, and bacteria • Diphtheria toxin produced by lysogenized C. diphtheriae • Prevented by DTaP and Td vaccine (Diphtheria toxoid) • Cutaneous diphtheria: Infected skin wound leads to slow healing ulcer Diphtheria
- 8. 2008 Otitis Media • S. pneumoniae (35%) • H. influenzae (20-30%) • M. catarrhalis (10-15%) • S. pyogenes (8-10%) • S. aureus (1-2%) • Treated with broad-spectrum antibiotics • Incidence of S. pneumoniae reduced by vaccine
- 10. 2008 • Rhinoviruses (50%) • Coronaviruses (15-20%) • Rhinoviruses attached to ICAN-1 on nasal mucosa Common cold
- 11. 2008 • Bacteria, viruses, & fungi cause: • Bronchitis • Bronchiolitis • Pneumonia Microbial Diseases of the Lower Respiratory System
- 12. 2008 Lower Respiratory System • The ciliary escalator keeps the lower respiratory system sterile. Figure 24.2
- 13. 2008 Pertussis (Whooping Cough) Figure 24.8 • Bordetella pertussis: Gram-negative coccobacillus • Capsule • Tracheal cytotoxin of cell wall damaged ciliated cells • Pertussis toxin • Prevented by DTaP vaccine (acellular Pertussis cell fragments)
- 14. 2008 • Stage 1: Catarrhal stage, like common cold • Stage 2: Paroxysmal stage: Violent coughing sieges • Stage 3: Convalescence stage Pertussis (Whooping Cough)
- 15. 2008 Tuberculosis Figure 24.9 • Mycobacterium tuberculosis: Acid-fast rod. Transmitted from human to human • M. bovis: <1% U.S. cases, not transmitted from human to human • M. avium-intracellulare complex infects people with late stage HIV infection
- 19. 2008 • Treatment of Tuberculosis: Prolonged treatment with multiple antibiotics • Vaccines: BCG, live, avirulent M. bovis. Not widely used in U.S. Tuberculosis
- 20. 2008 Tuberculosis Figure 24.11 • Diagnosis: Tuberculin skin test screening • + = current or previous infection • Followed by X-ray or CT, acid-fast staining of sputum, culturing bacteria
- 23. 2008 Pneumomoccal Pneumonia Figure 24.13 • Streptococcus pneumoniae: Gram-positive encapsulated diplococci • Diagnosis by culturing bacteria • Penicillin is drug of choice
- 25. 2008 • Gram-negative coccobacillus • Alcoholism, poor nutrition, cancer, or diabetes are predisposing factors • Second-generation cephalosporins Haemophilus influenzae Pneumonia
- 26. 2008 Mycoplasmal Pneumonia Figure 24.14 • Mycoplasma pneumoniae: pleomorphic, wall- less bacteria • Also called primary atypical pneumonia and walking pneumonia • Common in children and young adults • Diagnosis by PCR or by IgM antibodies
- 28. 2008 • Legionella pneumophila: Gram-negative rod • L. pneumophila is found in water • Transmitted by inhaling aerosols, not transmitted from human to human • Diagnosis: culturing bacteria • Treatment: Erythromycin Legionellosis
- 29. 2008 • Chlamydia psittaci: gram-negative intracellular bacterium • Transmitted by elementary bodies from bird dropping to humans • Reorganizes into reticulate body after being phagocytized • Diagnosis: culturing bacteria in eggs or cell culture • Treatment: Tetracycline Psittacosis (Ornithosis)
- 30. 2008 • Chlamydia pneumoniae • Transmitted from human to human • Diagnosis by FA test • Treatment: Tetracycline Chlamydial Pneumonia
- 31. 2008 Q fever • Mycoplasma pneumoniae: pleomorphic, wall-less bacteria • Also called primary atypical pneumonia and walking pneumonia • Common in children and young adults • Diagnosis by PCR or by IgM antibodies
- 33. 2008 • Viral pneumonia as a complication of influenza, measles, chickenpox • Viral etiology suspected if no cause determined • Respiratory Syncytial Virus (RSV) • Common in infants; 4500 deaths annually • Causes cell fusion (syncytium) in cell culture • Symptoms: coughing • Diagnosis by serologic test for viruses and antibodies • Treatment: Ribavirin Viral Pneumonia
- 34. 2008 • Chills, fever, headache, muscle aches (no intestinal symptoms) • 1% mortality due to secondary bacterial infections • Treatment: Amantadine • Vaccine for high-risk individuals Influenza
- 35. 2008 • Hemagglutinin (H) spikes used for attachment to host cells • Neuraminidase (N) spikes used to release virus from cell Influenza
- 37. 2008 • 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
- 38. 2008 • A: causes most epidemics, H3N2, H1N1, H2N2 • B: moderate, local outbreaks • C: mild disease Influenza serotypes
- 39. 2008 Histoplasmosis Figure 24.17 • Histoplasma capsulatum, dimorphic fungus (a) 37˚ (a) >35˚
- 40. 2008 Histoplasmosis Figure 24.18 • Transmitted by airborne conidia from soil • Diagnosis by culturing fungus • Treatment: amphotericin B
- 42. 2008 Coccidioidomycosis Figure 24.20 • Transmitted by airborne arthrospores • Diagnosis by serological tests or DNA probe • Treatment: amphotericin B
- 43. 2008 Pneumocystis Pneumonia Figure 24.22 • Pneumocystis jiroveci (P. carinii) found in healthy human lungs • Pneumonia occurs in newly infected infants & immunosuppressed individuals • Treatment: Timethoprim- sulfamethoxazole
- 44. 2008 Pneumocystis Figure 24.21 The mature cyst contains 8 intracystic bodies. The cyst ruptures, releasing the bodies. The bodies develop into trophozoites. 1 2 3 The trophozoites divide. 4 Each trophozoite develops into a mature cyst. 5 Cyst Intracystic bodies Trophozoite
- 45. 2008 • Blastomyces dermatitidis, dimorphic fungus • Found in soil • Can cause extensive tissue destruction • Treatment: amphotericin B Blastomycosis
- 46. 2008 • Aspergillus • Rhizopus • Mucor Opportunistic fungi involved in respiratory disease: Mucor rouxii Figure 12.2b, 12.4