Childhood Bacterial Infections

Question 1

Corynebacterium diphtheriae

Answer 1

• aerobic, gram(+) rod, pleomorphic
• P2P spread: respiratory droplets + oral secretions
• diphteria exotoxin–prevent protein synthesis–necrosis
• thick, gray, leathery membranous lesions from upper respiratory epithelium-tonsils (necrotic debris, fibrin, neutrophils,
• fever, sore throat, malaise -treated with antitoxin and antibiotics
• most in western world immunized
• peripheral nerve demyelination w/ neural involvement
• heart affected: fat droplets in myocytes and focal necrosis

Question 2

Bordetella Pertussis

Answer 2

• Gram(-) coccobacillus
• highly contagious, P2P: respiratory aerosols
• tracheobronchitis with necrosis of ciliated respiratory epithelium (acute inflamed response)
• Whooping cough: paroxysmal stage
• catarrhal stage: upp resp illness w/ low fever, runny nose, conjunctivitis, cough
• vaccine: unimmunized–50 million cases w/ 1 million deaths per year.
• secondary bacterial pneumonia–causes death

Question 3

Haemophilus influenzae

Answer 3

• aerobic, pleomorphic, gram(-) coccobacillus, nonencapsulated, capsulated(Type B): most virulent
• P2P spread: respiratory droplets and secretions
• Normal flora of oropharynx -pyogenic infection, MENINGITIS (#1 cause in <2 year olds)
• broncopneumonia, epiglottitis (obstruct airway), septic arthritis (bacteremic), facial cellulitis (bacteremic)
• vaccine: nearly eliminated infantile meningitis

Question 4

Neisseria meningitides (Meningococcus)

Answer 4

• paired, bean-shaped, gram(-) cocci
• commensual nasopharynx (5-15% population)
• epidemic in crowded areas (military barracks)
• P2P spread: respiratory droplets
• confined to CNS or disseminated
• fulminant fever, stiff neck, headache
• meningococcal sepsis: fever, shock, mucocutaneous hemmorhages, diffuse vascular endothelium damage, petechiae, purpura
• Rare: vasculitis, thrombosis–Waterhous-Friderichsen Syndrome (adrenal hemorrhagic necrosis)