Corynebacterium diphtheriae

Paul Auwaerter, M.D.

Corynebacterium diphtheriae is a topic covered in the Johns Hopkins ABX Guide.

To view the entire topic, please log in or purchase a subscription.

Official website of the Johns Hopkins Antibiotic (ABX), HIV, Diabetes, and Psychiatry Guides, powered by Unbound Medicine. Johns Hopkins Guide App for iOS, iPhone, iPad, and Android included. Explore these free sample topics:

A COVID-19 Conversation - Variants, Vaccines, and Long-Term Effects

Coronavirus COVID-19 (SARS-CoV-2)

Suicide Risk in the COVID-19 Pandemic

Moderna COVID-19 Vaccine

BNT162b2 COVID-19 Vaccine (BioNTech/Pfizer)

Managing Stress and Coping with COVID-19

Johnson & Johnson COVID-19 Vaccine

-- The first section of this topic is shown below --

MICROBIOLOGY

Pleomorphic Gram-positive bacillus that is club-shaped, appears like Chinese characters on Gram stain [Fig1].
- Facultative anaerobe.
- Humans are only known hosts.
Diphtheria caused only by exotoxin-producing strains of C. diphtheriae.
Three Corynebacterium strains may produce diphtheria toxin:
- C. diphtheriae (epidemic diphtheria w/ person-person spread)
- C. ulcerans
- C. pseudotuberculosis
- Both C. ulcerans and C. pseudotuberculosis are less common and associated with farm/dairy contacts.
Virulent C. diphtheria strains carry a bacteriophage with the diphtheria toxin gene. Without this bacteriophage, the microbe is unable to cause serious disease.
Culture best performed on tellurite-selective media, e.g., Tinsdale agar.
Confirmation of toxin production by the demonstration of an immunoprecipitation band done at CDC.

-- To view the remaining sections of this topic, please log in or purchase a subscription --

MICROBIOLOGY

Pleomorphic Gram-positive bacillus that is club-shaped, appears like Chinese characters on Gram stain [Fig1].
- Facultative anaerobe.
- Humans are only known hosts.
Diphtheria caused only by exotoxin-producing strains of C. diphtheriae.
Three Corynebacterium strains may produce diphtheria toxin:
- C. diphtheriae (epidemic diphtheria w/ person-person spread)
- C. ulcerans
- C. pseudotuberculosis
- Both C. ulcerans and C. pseudotuberculosis are less common and associated with farm/dairy contacts.
Virulent C. diphtheria strains carry a bacteriophage with the diphtheria toxin gene. Without this bacteriophage, the microbe is unable to cause serious disease.
Culture best performed on tellurite-selective media, e.g., Tinsdale agar.
Confirmation of toxin production by the demonstration of an immunoprecipitation band done at CDC.

There's more to see -- the rest of this entry is available only to subscribers.