24 Flashcards
Streptococcal pharyngitis
strep throat) – Caused by group A streptococci (GAS)
Streptococcus pyogenes
– Resistant phagocytosis
– Streptokinases lyse clots – Streptolysins are cytotoxic
Scarlet fever
Erythrogenic toxin produced by lysogenized S. pyogenes
Diphtheria
Corynebacterium diphtheriae – Gram-positive rod; pleomorphic
• Forms a tough grayish membrane in the throat – Fibrin and dead tissue
– Blocks passage of air to the lungs
• Exotoxin produced by lysogenized bacteria
– Circulates in the blood; damages the heart and kidneys
Cutaneous diphtheria
Corynebacterium diphtheriae
Transmission through direct contact and Forms skin
ulcer
Otitis Media
Streptococcus pneumoniae
– Nonencapsulated Haemophilus influenzae – Moraxella catarrhalis
– S. pyogenes
– respiratory syncytial viruses
Viral infections of upper respiratory system
Rhinoviruses coronaviruses enteroviruses there is no fever seen in viral infections
Pertussis
(Whooping Cough) (1 of 2)
• Caused by Bordetella pertussis – Gram-negative coccobacillus
• Produces a capsule
– Allows attachment to ciliated cells in the trachea
Destroys ciliated cells and shuts down the ciliary escalator
• Tracheal cytotoxin of cell wall damages ciliated cells. • Pertussis toxin enters the bloodstream.
Tuberculosis
Mycobacterium tuberculosis, mycobacterium Bovis mycobacterium avium intracellulare
Typical pneumonia
Streptococcus pneumoniae
Pneumococcal Pneumonia
S. pneumoniae
– Gram-positive; encapsulated diplococci – 90 serotypes
• Infected alveoli of the lung fill with fluids and RBCs; interferes with oxygen uptake
• Diagnosis: optochin-inhibition test, bile solubility test, or presence of capsular antigen in urine
Haemophilus Influenzae Pneumonia
Gram-negative coccobacillus
• Symptoms resemble those of pneumococcal
pneumonia
Mycoplasmal Pneumonia
called primary atypical pneumonia or walking pneumonia
• Caused by Mycoplasma pneumoniae – No cell wall
• Mild but persistent respiratory symptoms; low fever, cough, headache
– Common in children and young adults
• “Fried-egg” appearance on media
Legionellosis
Legionnaires’ disease
• Caused by Legionella pneumophila
– Aerobic, gram-negative rod
– Grows in water and air conditioning, biofilms, and waterborne amebae
• Transmitted by inhaling aerosols; not transmitted person to person
• Symptoms: high fever and cough
– Similar to symptoms of Pontiac fever
Psittacosis
Caused by Chlamydophila psittaci
– Gram-negative intracellular bacterium
• Transmitted to humans by elementary bodies from bird droppings transmitted through air
• Fever, headache, chills, disorientation
Ornithosis
Psittacosis
