Corynebacteria

CASE 1

• A 7 year old girl of Middle Eastern origin presents with inability to swallow and enlargement of the neck ("bull neck"). She has fever and severe throat pain.

• The child had received only an initial diphtheria-tetanus immunization as an infant.

• Examination revealed an acutely ill, febrile child (temperature = 39.1, heart rate= 139/min). The neck was symmetrically swollen. Examination of the oropharynx revealed a whitish-grey membrane covering the oropharynx and posterior tongue. Attempts to remove the membrane produced bleeding.

• Based on the appearance, a presumptive diagnosis of diphtheria was made.

Questions:

1. How is this organism acquired? What is the reservoir of infection in a typical community?
2. Individuals who are vaccinated may also carry this pathogen in their upper respiratory tract. Why is this possible?
3. What major virulence factor is responsible for the manifestations of this disease?
4. How did C. diphtheriae acquire this virulence factor?
3. What other form of disease does C. diphtheriae cause?