10 Questions
Which of the following is NOT a general characteristic of Corynebacterium?
Spore-forming
Which species of Corynebacterium is responsible for causing diphtheria?
C.diphtheriae
What is the major symptom of respiratory diphtheria?
White pseudomembrane over the throat
Which stain is used to visualize the metachromatic granules in Corynebacterium?
Albert's stain
What type of infection does C.ulcerans cause?
Systemic infections
Which selective media is used to differentiate commensal species from C. diphtheriae?
Hoyle's Tellurite blood agar
What is the purpose of Tindsdale medium?
To produce H2S
What is the mainstay of treatment for Diphtheria?
Antidiphtheritic serum (antitoxin)
Which antibiotics are sensitive for Diphtheria treatment?
Erythromycin, Penicillin & Clindamycin
Which test is used to identify C. diphtheriae through Ag-Ab interaction?
ELEK's test
Study Notes
General Characteristics of Corynebacterium
- Gram-positive, catalase positive, non-spore-forming, non-motile, rod-shaped bacteria
- Metachromatic granules are usually present representing stored phosphate regions
- Also known as the Klebs-Löffler bacillus
- Genus has many species
- Most commensals called Diptheroids
- Human pathogens include C.diphtheriae, C.hemolyticum, C.jeikium, and C.ulcerans
Diphtheria
- Respiratory diphtheria is more serious than cutaneous diphtheria
- Organism is inhaled and exotoxin (neurotoxin) spreads via blood to other organs
- Clinical diagnosis includes the presence of a membrane in the throat
- Lab diagnosis involves microscopy and culture
Lab Diagnosis
- Microscopy: Pleomorphic gram-positive bacilli, gram variable, coryneform (Chinese letter arrangement)
- Special stain: Albert's stain (KLB stain) to stain volutin (metachromatic polyphosphate granules)
- Culture: Selective media like Hoyle's Tellurite blood agar and Tinsdale medium
Identification of Corynebacterium diphtheriae
- Biochemical tests like Hiss's Serum sugars, urease, and gelatin liquefaction
- Virulence testing includes ELEK's test and Guinea pig inoculation
Treatment and Prevention
- Mainstay of treatment is Antidiphtheritic serum (antitoxin)
- Antibiotics used for treatment of carriers and in synergy with antitoxin
- Sensitive to Erythromycin, Penicillin, and Clindamycin
- Vaccination is important to prevent diphtheria
Test your knowledge on Gram-positive bacilli Corynebacterium! Learn about their general characteristics, including their Gram-positive nature, catalase positivity, non-spore-forming and non-motile behavior, as well as their rod-shaped structure. Discover their metachromatic granules that store phosphate regions and explore their association with the Klebs-Löffler bacillus. Challenge yourself and expand your understanding of this diverse genus.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
