1. Lower respiratory tract
Lungs are axenic (no normal flora)
Pneumonia
Described by location, pathogen or way contracted
Pleurisy

2. Pneumococcal Pneumonia
Most common bacterial pneumonia
Causative agent
Streptococcus pnuemoniae
Gram positive
Encapsulated, diplococci

3. Signs and Symptoms
Cough; fever; congestion; chest pain; rust tinged sputum
Breathing becomes shallow and rapid
Skin becomes dusky due to poor oxygenation
Consolidation may occur

4. Recovery is usually complete
Most strains do not cause permanent damage to lung tissue
Complications
Pleural effusions
Septicemia
Endocarditis
Meningitis

5. Epidemiology
75% of healthy individuals carry encapsulated strain in their throat
Bacterial rarely reach lung
Risk of pneumonia rises when cilia destroyed
Gram stain of sputum used for diagnosis
Pneumococci confirmed with quelling reaction

6. Bacteria that reach alveoli cause inflammatory response
Adhesions
Capsule
Phosphorylocholine in cell wall
Pneumolysin (cytotoxin)
IGA proteases

7. Prevention Treatment Pneumococcal vaccine
Antibiotics successful if given early
Penicillin (some resistance)
Erythromycin, cephalosporin and chloramphenicol

8. Klebsiella Pneumonia Leading cause of nosocomial pneumonia
Causative agent
Klebsiella pneumoniae
Gram negative
Encapsulated, Bacillus
Produce mucoid colonies

9. Organism causes tissue death
Signs and Symptoms:
Typical pneumonia symptoms combined with a thick, bloody sputum and recurrent chills
Organism causes tissue death
Leads to formation abscess in lung or other tissues
Endotoxin can trigger shock and disseminated intravascular coagulation

10. Epidemiology Endogenous
Difficult for K. pneumoniae to infect lungs of healthy persons
Leading causes of nosocomial death
Also causes UTI, meningitis and wound infections
Diagnosed with chest x-ray and sputum culture

11. Prevention Treatment No vaccine available
Employ good aseptic technique
Treatment
Antimicrobial treatment limited
Cephalosporin combined with an aminoglycoside
Tissue damage and release of endotoxin can cause permanent damage to lungs
High fatalities even with treatment

12. Mycoplasmal Pneumonia
“Walking pneumonia”
Leading pneumonia in children
Causative agent
Mycoplasma pneumoniae
Small, pleomorphic, Gram +
No cell wall
Prominent capsule

13. Signs and Symptoms Onset is gradual First symptoms include
1-4 week incubation period
First symptoms include
Fever, headache, muscle pain, fatigue, sore throat and excessive sweating
atypical for pneumonia
Persistent dry cough for several weeks

14. Organism attaches to receptors on epithelium Adhesion protein
Interferes with cilia, cells die and slough off
Capsule protects it from phagocytosis
Inflammation initiates thickening of bronchial and alveolar walls
Causes difficulty in breathing

15. Spread through aerosol droplets Grow slowly in culture
Epidemiology
Spread through aerosol droplets
Survive for long periods in secretions
Grow slowly in culture
2-6 weeks for “fried egg” colonies to appear
Diagnosis difficult
Serological tests required

16. Prevention and treatment
No practical prevention
Avoid crowding in schools and military facilities
Aseptic technique
Antibiotic treatment
Penicillins are ineffectual (WHY?)
Antibiotics of choice are tetracycline and erythromycin

17. Pertussis Whooping Cough Causative agent Bordetella pertussis
Small, Gram negative
Encapsulated, coccobacillus

18. Catarrhal stage – cold symptoms (1-2 weeks)
Signs and Symptoms:
Catarrhal stage – cold symptoms (1-2 weeks)
Paroxysmal stage – severe coughing (2-4 weeks)
Coughing followed by characteristic “whoop”
May cause vessels in eyes to rupture
Cyanosis
Vomiting, diarrhea and seizure may occur
Convalescent phase –persistent cough (months)

19. Pathogen enters respiratory tract and attaches to ciliated cells
Produces 2 forms of adhesions
Colonizes upper and lower respiratory tract
Produces numerous toxic products
Mucus secretion increases and cilia action decreases
Cough reflex is only mechanism for clearing secretions
Decreased blood flow and WBC activity

20. Epidemiology Spreads via infected respiratory droplets
Highly contagious
Most infectious during runny nose period
Classically disease of infants
Often overlooked as a persistent cold in adults
High risk of secondary infections!

21. Prevention Treatment Immunization Primarily supportive
Combined with Diphtheria and tetanus toxoids
DTaP
Treatment
Primarily supportive
Erythromycin may reduce infectivity if given early

22. Tuberculosis TB; Consumption Causative agent
Mycobacterium tuberculosis
Gram positive
Acid fast, slender bacillus
Cord factor

23. Signs and Symptoms Chronic illness Initial symptoms:
Minor cough and mild fever
Progressive symptoms:
Fatigue; night sweats; weight loss; chest pain and labored breathing
Chronic productive cough
Sputum often bloody

24. 3 types of tuberculosis:
Primary TB- initial case of tuberculosis disease
Secondary TB - reactivated
Disseminated TB- tuberculosis involving multiple systems

25. Primary TB Transmitted through respiratory droplets
Pathogens taken up by alveolar macrophages
fusion of phagosome with lysosomes prevented
Pathogen replicates inside macrophages slowly killing them
Intense immune reaction occurs
WBCs surround infected cells and release inflammatory chemicals

26. Other body cells deposit collagen fibers
macrophages and lung cells form tubercle
Infected cells die producing caseous (cheesy) necrosis
Body may deposit calcium around tubercles
Ghon complex

27. Secondary TB Disseminated TB
tubercle ruptures and reestablishes active infection
More common in immunosupressed
Leading killer of HIV+ individuals
Disseminated TB
Some macrophages carry pathogen through blood and lymph to other sites of body
Bone marrow, spleen, kidneys, spinal cord and brain

29. Epidemiology 1/3 of world population infected
Annual mortality of ~ 2 million
Estimated 10 million Americans infected
Rate highest among non-white, elderly poor people
Small infecting dose
As little as ten inhaled organisms
Not very virulent but high mortality

30. Tuberculin test Tuberculosis antigen injected under skin
Injection site become red and firm if positive
Positive test does not indicate active disease
Definitive tests include sputum samples and chest x-rays

31. Prevention Treatment Vaccination used in other parts of the world
Prophylactic antibacterial treatment for exposed individuals
Treatment
Antibiotic treatment
Rifampin, Isoniazid, streptomycin and ethambutol
MDR strains
Therapy lasts up to 6 months (DOTS)