Presentation on theme: "Microbial Diseases of the Respiratory System"— Presentation transcript:
1Microbial Diseases of the Respiratory System Chapter 24Microbial Diseases of the Respiratory System
2Q&AHow do these bacteria, by growing on these particular body cells, cause the disease pertussis?
3The Respiratory System Learning Objectives24-1 Describe how microorganisms are prevented from entering the respiratory system.24-2 Characterize the normal microbiota of the upper and lower respiratory systems.
4The Upper Respiratory System NosePharynx (throat)Middle earEustachian tubes
5Structures of Upper Respiratory System Figure 24.1
6The Lower Respiratory System LarynxTracheaBronchial tubesAlveoliPleura
7Structures of Lower Respiratory System Figure 24.2
8Normal Microbiota of Respiratory System Suppress pathogens by competitive inhibition in upper respiratory systemLower respiratory system is sterile
9What 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
10Upper Respiratory System Diseases Learning Objectives24-3 Differentiate pharyngitis, laryngitis, tonsillitis, sinusitis, and epiglottitis.24-4 List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for streptococcal pharyngitis, scarlet fever, diphtheria, cutaneous diphtheria, and otitis media.24-5 List the causative agents and treatments for the common cold.
11Upper Respiratory System Diseases PharyngitisLaryngitisTonsillitisSinusitisEpiglottitis: H. influenzae type b
12Streptococcal Pharyngitis Also called strep throatStreptococcus pyogenesResistant to phagocytosisStreptokinases lyse clotsStreptolysins are cytotoxicDiagnosis by enzyme immunoassay (EIA) testsFigure 24.3
13Scarlet Fever Streptococcus pyogenes Pharyngitis Erythrogenic toxin produced by lysogenized S. pyogenes
14Diphtheria Corynebacterium diphtheriae: Gram-positive rod Diphtheria toxin produced by lysogenized C. diphtheriaeFigure 24.4
16Diphtheria Prevented by DTaP vaccine Cutaneous diphtheria Diphtheria toxoidCutaneous diphtheriaInfected skin wound leads to slow-healing ulcer
17Otitis 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 vaccineFigure 24.6
18The Common ColdRhinoviruses (50%)Coronaviruses (15–20%)
19Which one of the following is most likely to be associated with a headache: pharyngitis, laryngitis, sinusitis, or epiglottitis? 24-3Among streptococcal pharyngitis, scarlet fever, or diphtheria, which two diseases are usually caused by the same genus of bacteria? 24-4Which viruses, rhinoviruses or coronaviruses, cause about half of cases of the common cold? 24-5
20Diseases 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?
21Lower Respiratory System Diseases Learning Objectives24-6 List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for pertussis and tuberculosis.24-7 Compare and contrast the seven bacterial pneumonias discussed in this chapter.24-8 List the etiology, method of transmission, and symptoms of melioidosis.
22Lower Respiratory System Diseases Bacteria, viruses, and fungi causeBronchitisBronchiolitisPneumonia
41Pneumococcal Pneumonia Symptoms: Infected alveoli of lung fill with fluids; interferes with oxygen uptakeDiagnosis: Optochin-inhibition test or bile solubility test; serological typing of bacteriaTreatment: Penicillin, fluoroquinolonesPrevention: Pneumococcal vaccine
42Haemophilus influenzae Pneumonia Gram-negative coccobacillusPredisposing factors: Alcoholism, poor nutrition, cancer, or diabetesSymptoms: Resemble those of pneumococcal pneumoniaDiagnosis: Isolation; special media for nutritional requirementsTreatment: Cephalosporins
43Mycoplasmal Pneumonia Primary atypical pneumonia; walking pneumoniaMycoplasma pneumoniaePleomorphic, wall-less bacteriaCommon in children and young adultsFigure 24.13
45Mycoplasmal Pneumonia Symptoms: Mild but persistent respiratory symptoms; low fever, cough, headacheDiagnosis: PCR and serological testingTreatment: Tetracyclines
46Legionellosis Legionella pneumophila Found in water Gram-negative rodFound in waterTransmitted by inhaling aerosols; not transmitted from human to humanClinical Focus, p. 691
47LegionellosisSymptoms: Potentially fatal pneumonia that tends to affect older men who drink or smoke heavilyDiagnosis: Culture on selective media, DNA probeTreatment: Erythromycin
48Psittacosis (Ornithosis) Chlamydophila psittaciGram-negative intracellular bacteriumTransmitted to humans by elementary bodies from bird droppingsReorganizes into reticulate body after being phagocytized
49Psittacosis (Ornithosis) Symptoms: Symptoms, if any, are fever, headache, chillsDiagnosis: Growth of bacteria in eggs or cell cultureTreatment: Tetracyclines
51Chlamydial Pneumonia Chlamydophila pneumoniae Transmitted from human to humanFigure 11.24b
52Chlamydial PneumoniaSymptoms: Mild respiratory illness common in young people; resembles mycoplasmal pneumoniaDiagnosis: Serological testsTreatment: Tetracyclines
53Q Fever Causative agent: Coxiella burnetii Reservoir: Large mammals Tick vectorCan be transmitted via unpasteurized milk
54Coxiella burnetii, the Cause of Q Fever Figure 24.14
55Q FeverSymptoms: Mild respiratory disease lasting 1–2 weeks; occasional complications such as endocarditis occurDiagnosis: Growth in cell cultureTreatment: Doxycycline and chloroquine
56Melioidosis Causative agent: by Burkholderia pseudomallei Reservoir: SoilMainly in southeast Asia and northern AustraliaSymptoms: Pneumonia, or tissue abscesses and severe sepsisDiagnosis: Bacterial cultureTreatment: Ceftazidime
57Diseases 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?
58Another name for pertussis is whooping cough Another name for pertussis is whooping cough. This symptom is caused by the pathogens’ attack on which cells? 24-6What group of bacterial pathogens causes what is informally called “walking pneumonia”? 24-7The bacterium causing melioidosis in humans also causes a disease of horses known as what? 24-8
59Lower Respiratory System Diseases Learning Objective24-9 List the causative agent, symptoms, prevention, and preferred treatment for viral pneumonia, RSV, and influenza.
60Viral PneumoniaViral pneumonia occurs as a complication of influenza, measles, or chickenpoxViral etiology suspected if no other cause is determined
61Respiratory Syncytial Virus (RSV) Common in infants; 4500 deaths annuallyCauses cell fusion (syncytium) in cell cultureSymptoms: Pneumonia in infantsDiagnosis: Serological test for viruses and antibodiesTreatment: Ribavirin, palivizumab
62Influenza (Flu) Symptoms: Chills, fever, headache, and muscle aches No intestinal symptoms1% mortality, very young and very oldTreatment: Zanamivir and oseltamivir inhibit neuraminidaseProphylaxis: Multivalent vaccine
63The Influenza VirusHemagglutinin (HA) spikes used for attachment to host cellsNeuraminidase (NA) spikes used to release virus from cellFigure 24.15
64The Influenza Virus Antigenic shift Antigenic drift Changes in HA and NA spikesProbably due to genetic recombination between different strains infecting the same cellAntigenic driftPoint mutations in genes encoding HA or NA spikesMay involve only 1 amino acidAllows virus to avoid mucosal IgA antibodies
65Influenza Serotypes Type Antigenic Subtype Year Severity A H3N2 H1N1 18891918195719681977ModerateSevereLowBNone1940C1947Very mild
66Is reassortment of the RNA segments of the influenza virus the cause of antigenic shift or antigenic drift? 24-9
67Lower Respiratory System Diseases Learning Objective24-10 List the causative agent, mode of transmission, preferred treatment, and laboratory identification tests for four fungal diseases of the respiratory system.
75Blastomycosis Causative agent: Blastomyces dermatitidis Reservoir: Soil in Mississippi valley areaSymptoms: Abscesses; extensive tissue damageDiagnosis: Isolation of pathogenTreatment: Amphotericin B
76Other Fungi Involved in Respiratory Disease SystemicPredisposing factors:Immunocompromised stateCancerDiabetesAspergillus fumigatusMucorRhizopus
77The 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
78Diseases 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?