How does Elek test work?
Elek test detects the development of an immunoprecipitin band on a filter paper impregnated with antitoxin and then is laid over an agar culture of the organism being tested. Polymerase chain reaction (PCR) assays for detection of DNA sequence encoding the A subunit of tox+ strain are both rapid and sensitive.
Which test is used to find out the presence of diphtheria?
Diagnosis of diphtheria is confirmed by culture of the organism from the specimen and by demonstrating toxin production using an immunoprecipitation reaction (the modified Elek test).
What is the culture medium used in Elek test?
Elek immunodiffusion test. Sterile filter paper impregnated with diphtheria antitoxin is imbedded in agar culture medium. Isolates of C diphtheriae are then streaked across the plate at an angle of 90° to the antitoxin strip.
How do you identify Corynebacterium diphtheriae?
Corynebacterium diphtheriae is a slender, Gram-positive bacillus, usually with one end being wider, thus giving the often-described club-shaped appearance. On culture, particularly under suboptimal conditions, characteristic bands or granules appear.
What does Toxigenicity mean?
toxigenicity. The ability of a pathogenic organism to produce injurious substances that damage the host.
What is Elek precipitation test?
Elek’s test or the Elek plate test is an in vitro test of virulence performed on specimens of Corynebacterium diphtheriae, the bacteria that causes diphtheria. It is used to test for toxigenicity of C. diphtheriae strains. The test uses immunodiffusion.
Is diphtheria a virus?
Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make a toxin (poison). It is the toxin that can cause people to get very sick. Diphtheria bacteria spread from person to person, usually through respiratory droplets, like from coughing or sneezing.
What is the size of diphtheria?
Diphtheria toxin (DT) is together with CT the best studied enterotoxin with regard to its structure and function. DT is a 58-kDa protein produced as a single polypeptide by lysogenic Corynebacterium diphtheriae strains.
What does C. diphtheriae cause?
Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make toxin (poison). It can lead to difficulty breathing, heart failure, paralysis, and even death. CDC recommends vaccines for infants, children, teens, and adults to prevent diphtheria. search icon.
Is Corynebacterium diphtheriae gram positive?
C. diphtheriae is a pleomorphic, club-shaped, Gram positive bacillus that is catalase positive, non-motile, non-spore forming, and non-acid fast.
How do you test for Corynebacterium?
Basic tests for Corynebacteria identification include Gram staining and cell morphology, size, pigmentation, odour and haemolysis of colonies, CAMP reaction, lipophilia, motility and biochemical tests such as catalase and pyrazinamidase production, nitrate reduction, urea hydrolysis, esculin hydrolysis, acid production …