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Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 24 Microbial Diseases of the Respiratory System.

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Presentation on theme: "Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 24 Microbial Diseases of the Respiratory System."— Presentation transcript:

1 Copyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case Chapter 24 Microbial Diseases of the Respiratory System

2 Copyright © 2010 Pearson Education, Inc. Q&A  How do these bacteria, by growing on these particular body cells, cause the disease pertussis?

3 Copyright © 2010 Pearson Education, Inc. The Respiratory System 24-1Describe how microorganisms are prevented from entering the respiratory system. 24-2Characterize the normal microbiota of the upper and lower respiratory systems. Learning Objectives

4 Copyright © 2010 Pearson Education, Inc. The Upper Respiratory System  Nose  Pharynx (throat)  Middle ear  Eustachian tubes

5 Copyright © 2010 Pearson Education, Inc. Structures of Upper Respiratory System Figure 24.1

6 Copyright © 2010 Pearson Education, Inc. The Lower Respiratory System  Larynx  Trachea  Bronchial tubes  Alveoli  Pleura

7 Copyright © 2010 Pearson Education, Inc. Structures of Lower Respiratory System Figure 24.2

8 Copyright © 2010 Pearson Education, Inc. Normal Microbiota of Respiratory System  Suppress pathogens by competitive inhibition in upper respiratory system  Lower respiratory system is sterile

9 Copyright © 2010 Pearson Education, Inc. Check Your Understanding What is the function of hairs in the nasal passages? 24-1 Normally, the lower respiratory tract is nearly sterile. What is the primary mechanism responsible? 24-2

10 Copyright © 2010 Pearson Education, Inc. Upper Respiratory System Diseases 24-3Differentiate pharyngitis, laryngitis, tonsillitis, sinusitis, and epiglottitis. 24-4List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for streptococcal pharyngitis, scarlet fever, diphtheria, cutaneous diphtheria, and otitis media. 24-5List the causative agents and treatments for the common cold. Learning Objectives

11 Copyright © 2010 Pearson Education, Inc. Upper Respiratory System Diseases  Pharyngitis  Laryngitis  Tonsillitis  Sinusitis  Epiglottitis: H. influenzae type b

12 Copyright © 2010 Pearson Education, Inc. Streptococcal Pharyngitis  Also called strep throat  Streptococcus pyogenes  Resistant to phagocytosis  Streptokinases lyse clots  Streptolysins are cytotoxic  Diagnosis by enzyme immunoassay (EIA) tests Figure 24.3

13 Copyright © 2010 Pearson Education, Inc. Scarlet Fever  Streptococcus pyogenes  Pharyngitis  Erythrogenic toxin produced by lysogenized S. pyogenes

14 Copyright © 2010 Pearson Education, Inc. Diphtheria  Corynebacterium diphtheriae: Gram-positive rod  Diphtheria toxin produced by lysogenized C. diphtheriae Figure 24.4

15 Copyright © 2010 Pearson Education, Inc. Diphtheria  Diphtheria membrane: Fibrin, tissue, bacterial cells Figure 24.5

16 Copyright © 2010 Pearson Education, Inc. Diphtheria  Prevented by DTaP vaccine  Diphtheria toxoid  Cutaneous diphtheria  Infected skin wound leads to slow-healing ulcer

17 Copyright © 2010 Pearson Education, Inc. Otitis Media  S. pneumoniae (35%)  H. influenzae (20–30%)  M. catarrhalis (10–15%)  S. pyogenes (8–10%)  S. aureus (1–2%)  Incidence of S. pneumoniae reduced by vaccine Figure 24.6

18 Copyright © 2010 Pearson Education, Inc. The Common Cold  Rhinoviruses (50%)  Coronaviruses (15 – 20%)

19 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Which one of the following is most likely to be associated with a headache: pharyngitis, laryngitis, sinusitis, or epiglottitis? 24-3 Among streptococcal pharyngitis, scarlet fever, or diphtheria, which two diseases are usually caused by the same genus of bacteria? 24-4 Which viruses, rhinoviruses or coronaviruses, cause about half of cases of the common cold? 24-5

20 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Diseases of the Upper Respiratory System  A patient presents with fever and a red, sore throat. Later, a grayish membrane appears in the throat. Gram-positive rods were cultured from the membrane.  Can you identify infections that could cause these symptoms?

21 Copyright © 2010 Pearson Education, Inc. Lower Respiratory System Diseases 24-6List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for pertussis and tuberculosis. 24-7Compare and contrast the seven bacterial pneumonias discussed in this chapter. 24-8List the etiology, method of transmission, and symptoms of melioidosis. Learning Objectives

22 Copyright © 2010 Pearson Education, Inc.  Bacteria, viruses, and fungi cause  Bronchitis  Bronchiolitis  Pneumonia Lower Respiratory System Diseases

23 Copyright © 2010 Pearson Education, Inc. Pertussis (Whooping Cough)  Bordetella pertussis  Gram-negative coccobacillus  Capsule  Tracheal cytotoxin of cell wall damaged ciliated cells  Pertussis toxin  Prevented by DTaP vaccine (acellular Pertussis cell fragments) Figure 24.7

24 Copyright © 2010 Pearson Education, Inc. Pertussis (Whooping Cough)  Stage 1: Catarrhal stage, like common cold  Stage 2: Paroxysmal stage—violent coughing sieges  Stage 3: Convalescence stage

25 Copyright © 2010 Pearson Education, Inc. Q&A  How do these bacteria, by growing on these particular body cells, cause the disease pertussis?

26 Copyright © 2010 Pearson Education, Inc. Tuberculosis  Mycobacterium tuberculosis  Acid-fast rod; transmitted from human to human Figure 24.8

27 Copyright © 2010 Pearson Education, Inc. Tuberculosis  M. bovis: <1% U.S. cases; not transmitted from human to human  M. avium-intracellulare complex infects people with late-stage HIV infection

28 Copyright © 2010 Pearson Education, Inc. Tuberculosis Clinical Focus, p. 144

29 Copyright © 2010 Pearson Education, Inc. Tuberculosis Figure 14.10c

30 Copyright © 2010 Pearson Education, Inc. Worldwide Distribution of Tuberculosis Figure 24.11a

31 Copyright © 2010 Pearson Education, Inc. U.S. Distribution of Tuberculosis Figure 24.11b

32 Copyright © 2010 Pearson Education, Inc. The Pathogenesis of Tuberculosis Figure 24.9

33 Copyright © 2010 Pearson Education, Inc. The Pathogenesis of Tuberculosis Figure 24.9

34 Copyright © 2010 Pearson Education, Inc. The Pathogenesis of Tuberculosis Figure 24.9

35 Copyright © 2010 Pearson Education, Inc. The Pathogenesis of Tuberculosis Figure 24.9

36 Copyright © 2010 Pearson Education, Inc. The Pathogenesis of Tuberculosis Figure 24.9

37 Copyright © 2010 Pearson Education, Inc. Treatment of Tuberculosis  Treatment: Prolonged treatment with multiple antibiotics  Vaccines: BCG, live, avirulent M. bovis; not widely used in United States

38 Copyright © 2010 Pearson Education, Inc. A Positive Tuberculin Skin Test Figure 24.10

39 Copyright © 2010 Pearson Education, Inc. Diagnosis of Tuberculosis  Tuberculin skin test screening  Positive reaction means current or previous infection  Followed by X-ray or CT exam, acid-fast staining of sputum, culturing of bacteria

40 Copyright © 2010 Pearson Education, Inc. Pneumococcal Pneumonia  Streptococcus pneumoniae  Gram-positive encapsulated diplococci Figure 24.12

41 Copyright © 2010 Pearson Education, Inc. Pneumococcal Pneumonia  Symptoms: Infected alveoli of lung fill with fluids; interferes with oxygen uptake  Diagnosis: Optochin-inhibition test or bile solubility test; serological typing of bacteria  Treatment: Penicillin, fluoroquinolones  Prevention: Pneumococcal vaccine

42 Copyright © 2010 Pearson Education, Inc. Haemophilus influenzae Pneumonia  Gram-negative coccobacillus  Predisposing factors: Alcoholism, poor nutrition, cancer, or diabetes  Symptoms: Resemble those of pneumococcal pneumonia  Diagnosis: Isolation; special media for nutritional requirements  Treatment: Cephalosporins

43 Copyright © 2010 Pearson Education, Inc. Mycoplasmal Pneumonia  Primary atypical pneumonia; walking pneumonia  Mycoplasma pneumoniae  Pleomorphic, wall-less bacteria  Common in children and young adults Figure 24.13

44 Copyright © 2010 Pearson Education, Inc. Mycoplasma pneumoniae Figure 11.20

45 Copyright © 2010 Pearson Education, Inc. Mycoplasmal Pneumonia  Symptoms: Mild but persistent respiratory symptoms; low fever, cough, headache  Diagnosis: PCR and serological testing  Treatment: Tetracyclines

46 Copyright © 2010 Pearson Education, Inc. Legionellosis  Legionella pneumophila  Gram-negative rod  Found in water  Transmitted by inhaling aerosols; not transmitted from human to human Clinical Focus, p. 691

47 Copyright © 2010 Pearson Education, Inc.  Symptoms: Potentially fatal pneumonia that tends to affect older men who drink or smoke heavily  Diagnosis: Culture on selective media, DNA probe  Treatment: Erythromycin Legionellosis

48 Copyright © 2010 Pearson Education, Inc. Psittacosis (Ornithosis)  Chlamydophila psittaci  Gram-negative intracellular bacterium  Transmitted to humans by elementary bodies from bird droppings  Reorganizes into reticulate body after being phagocytized

49 Copyright © 2010 Pearson Education, Inc. Psittacosis (Ornithosis)  Symptoms: Symptoms, if any, are fever, headache, chills  Diagnosis: Growth of bacteria in eggs or cell culture  Treatment: Tetracyclines

50 Copyright © 2010 Pearson Education, Inc. Psittacosis (Ornithosis) Figure 11.24a

51 Copyright © 2010 Pearson Education, Inc. Chlamydial Pneumonia  Chlamydophila pneumoniae  Transmitted from human to human Figure 11.24b

52 Copyright © 2010 Pearson Education, Inc. Chlamydial Pneumonia  Symptoms: Mild respiratory illness common in young people; resembles mycoplasmal pneumonia  Diagnosis: Serological tests  Treatment: Tetracyclines

53 Copyright © 2010 Pearson Education, Inc. Q Fever  Causative agent: Coxiella burnetii  Reservoir: Large mammals  Tick vector  Can be transmitted via unpasteurized milk

54 Copyright © 2010 Pearson Education, Inc. Coxiella burnetii, the Cause of Q Fever Figure 24.14

55 Copyright © 2010 Pearson Education, Inc. Q Fever  Symptoms: Mild respiratory disease lasting 1–2 weeks; occasional complications such as endocarditis occur  Diagnosis: Growth in cell culture  Treatment: Doxycycline and chloroquine

56 Copyright © 2010 Pearson Education, Inc. Melioidosis  Causative agent: by Burkholderia pseudomallei  Reservoir: Soil  Mainly in southeast Asia and northern Australia  Symptoms: Pneumonia, or tissue abscesses and severe sepsis  Diagnosis: Bacterial culture  Treatment: Ceftazidime

57 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Common Bacterial Pneumonias  A 27-year-old man with a history of asthma was hospitalized with a 4-day history of progressive cough and 2 days of spiking fevers. Gram- positive cocci in pairs were cultured from a blood sample.  Can you identify infections that could cause these symptoms?

58 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Another name for pertussis is whooping cough. This symptom is caused by the pathogens’ attack on which cells? 24-6 What group of bacterial pathogens causes what is informally called “walking pneumonia”? 24-7 The bacterium causing melioidosis in humans also causes a disease of horses known as what? 24-8

59 Copyright © 2010 Pearson Education, Inc. Lower Respiratory System Diseases 24-9List the causative agent, symptoms, prevention, and preferred treatment for viral pneumonia, RSV, and influenza. Learning Objective

60 Copyright © 2010 Pearson Education, Inc. Viral Pneumonia  Viral pneumonia occurs as a complication of influenza, measles, or chickenpox  Viral etiology suspected if no other cause is determined

61 Copyright © 2010 Pearson Education, Inc. Respiratory Syncytial Virus (RSV)  Common in infants; 4500 deaths annually  Causes cell fusion (syncytium) in cell culture  Symptoms: Pneumonia in infants  Diagnosis: Serological test for viruses and antibodies  Treatment: Ribavirin, palivizumab

62 Copyright © 2010 Pearson Education, Inc. Influenza (Flu)  Symptoms: Chills, fever, headache, and muscle aches  No intestinal symptoms  1% mortality, very young and very old  Treatment: Zanamivir and oseltamivir inhibit neuraminidase  Prophylaxis: Multivalent vaccine

63 Copyright © 2010 Pearson Education, Inc. The Influenza Virus  Hemagglutinin (HA) spikes used for attachment to host cells  Neuraminidase (NA) spikes used to release virus from cell Figure 24.15

64 Copyright © 2010 Pearson Education, Inc. The Influenza Virus  Antigenic shift  Changes in HA and NA spikes  Probably due to genetic recombination between different strains infecting the same cell  Antigenic drift  Point mutations in genes encoding HA or NA spikes  May involve only 1 amino acid  Allows virus to avoid mucosal IgA antibodies

65 Copyright © 2010 Pearson Education, Inc. Influenza Serotypes TypeAntigenic Subtype YearSeverity AH3N2 H1N1 H2N2 H3N2 H1N Moderate Severe Moderate Low BNone1940Moderate CNone1947Very mild

66 Copyright © 2010 Pearson Education, Inc. Check Your Understanding Is reassortment of the RNA segments of the influenza virus the cause of antigenic shift or antigenic drift? 24-9

67 Copyright © 2010 Pearson Education, Inc. Lower Respiratory System Diseases 24-10List the causative agent, mode of transmission, preferred treatment, and laboratory identification tests for four fungal diseases of the respiratory system. Learning Objective

68 Copyright © 2010 Pearson Education, Inc. Histoplasmosis  Histoplasma capsulatum, dimorphic fungus Figure 24.16

69 Copyright © 2010 Pearson Education, Inc. Histoplasmosis Distribution Figure 24.17

70 Copyright © 2010 Pearson Education, Inc. Coccidioidomycosis  Causative agent: Coccidioides immitis  Reservoir: Desert soils of Southwest U.S.  Symptoms: Fever, coughing, weight loss  Diagnosis: Serological tests  Treatment: Amphotericin B

71 Copyright © 2010 Pearson Education, Inc. The Life Cycle of Coccidioides immitis Figure 24.18

72 Copyright © 2010 Pearson Education, Inc. U.S. Endemic Area for Coccidioidomycosis Figure 24.19

73 Copyright © 2010 Pearson Education, Inc. Pneumocystis Pneumonia  Causative agent: Pneumocystis jirovecii  Reservoir: Unknown; possibly humans or soil  Symptoms: Pneumonia  Diagnosis: Microscopy  Treatment: Trimethoprim

74 Copyright © 2010 Pearson Education, Inc. Figure 24.20

75 Copyright © 2010 Pearson Education, Inc. Blastomycosis  Causative agent: Blastomyces dermatitidis  Reservoir: Soil in Mississippi valley area  Symptoms: Abscesses; extensive tissue damage  Diagnosis: Isolation of pathogen  Treatment: Amphotericin B

76 Copyright © 2010 Pearson Education, Inc. Other Fungi Involved in Respiratory Disease  Systemic  Predisposing factors:  Immunocompromised state  Cancer  Diabetes  Aspergillus fumigatus  Mucor  Rhizopus

77 Copyright © 2010 Pearson Education, Inc. Check Your Understanding The droppings of both blackbirds and bats support the growth of Histoplasma capsulatum; which of these two animal reservoirs is normally actually infected by the fungus? 24-10

78 Copyright © 2010 Pearson Education, Inc. Diseases in Focus: Diseases of the Lower Respiratory System  A worker was hospitalized for acute respiratory illness. He had been near a colony of bats. The mass was surgically removed. Microscopic examination of the mass revealed ovoid yeast cells.  Can you identify infections that could cause these symptoms?


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