C Respiratory Tract Infections - Chapter 24

Streptococcal Pharyngitis (upper)

-Streptococcus pyogenes

(refer to notes in the skin and systemic sections about this microorganism)

Diphtheria (upper)

-Cromebacterium diphtheria

--makes exotoxin (carried on prophage) which inhibits protein synthesis

--Causes pseudo membrane formation in airway during invocation, can cause suffocation if left untreated

-exotoxin can enter circulation and damage organs

-humans: only natural host

-toxic part of DTP vaccine

Pertussis

(Whooping Cough) (lower)

-Bordetella pertussis

--Only infects humans

---makes tracheal cytotoxin, pertussis toxin, and endotoxin

-Stages of disease

1. Catarrhal stage (common cold symptoms)

2. Paroxysmal (violent coughing with potential complication of cyanosis from mucus buildup= lack of air)

3. Convalescent stage: chance for secondary infections

-Part of DTP vaccine as a whole cell extract,

--recently reformulated to include only certain proteins from the organism

Pneumonia (lower)

-Streptococcus pneumonia (other organisms too)

-major virulence factor: capsule

-VACCINE, recommended for children and older adults

Mycoplasma Pneumonia (lower)

-Mycoplasma pneumonia (lacks peptidoglycan layer)

-aka primary atypical (not common) pneumonia "walking pneumonia" (respiratory, cannot walk)

Legionnaires Disease (lower)

-Legionella pneumophila, gram negative rod

-survives in macrophages

-transmitted by aerosol

(AC, humidifiers, hospital waterlines, etc)

Tuberculosis (lower)

-Mycobaterium tuberculosis

-slow growth

-survives in macrophages, WBCs, and sputum for months

-tubercles: lung lesions with tissue death

-Miliary tuberculosis: spread in circulation and infect more organs including bones

-infection rates increase, developing resistance to drugs

--must give antibiotics for months as it takes a long time (resistance)

-dormant until reactivated if person becomes immunocompromised

-treatment: drug cocktails to treat infections:

Isoniazid, riampin, pyrazinamide, ethambutol

-vaccine effectiveness is questionable (more effective for kids)

-diagnosis: skin test

-M. bovis: can infect humans through unpasteurizedmilk

-Carbon fusion test under microscope to look at organism (ethanol/acid wash)