Why is CGD catalase positive?
These catalase positive bacteria break down hydrogen peroxide, which the host’s immune system uses to fight infection. As a consequence, catalase negative bacteria, such as Streptococci, rarely cause problems in CGD because hydrogen peroxide can accumulate to protect against infection.
When was chronic granulomatous disease discovered?
Chronic granulomatous disease (CGD) was first identified in the 1950s in a 12-month-old Minnesotan child who presented with a constellation of findings, including chronic suppurative lymphadenitis, hepatosplenomegaly, pulmonary infiltrates, and eczematoid dermatitis.
Who discovered CGD?
History. This condition was first described in 1954 by Janeway, who reported five cases of the disease in children. In 1957 it was further characterized as “a fatal granulomatosus of childhood”.
What is enzyme defect in CGD?
Chronic granulomatous disease is a genetic disease. In CGD, mutations in any one of five different genes can cause a defect in an enzyme called phagocyte NADPH oxidase. Certain white blood cells use this enzyme to produce hydrogen peroxide, which these cells need in order to kill certain bacteria and fungi.
How do you remember positive catalase bacteria?
The mnemonic can be used to memorise the catalase-positive bacteria (and Candida and Aspergillus, which are fungi): nocardia, pseudomonas, listeria, aspergillus, candida, E. coli, staphylococcus, serratia, B. cepacia and H. pylori.
Which organisms are catalase positive?
Staphylococcus and Micrococcus spp. are catalase positive, whereas Streptococcus and Enterococcus spp. are catalase negative.
How do you test for CGD?
Your doctor may order several tests to diagnose CGD , including: Neutrophil function tests. Your doctor may conduct a dihydrorhodamine 123 (DHR) test or other tests to see how well a type of white blood cell (neutrophil) in your blood is functioning. Doctors usually use this test to diagnose CGD .
How serious is CGD?
People with CGD can experience: Serious, sudden, and frequent infections in many areas of the body, including the lungs, liver, or bones. Skin infections that cause boils, blisters, and sores that don’t go away. Bowel problems from inflammation in the intestines, such as diarrhea, weight loss, and abdominal pain.
What causes CGD?
Causes. CGD is caused by defects in an enzyme, NADPH oxidase, that phagocytes need to kill certain bacteria and fungi. Mutations in one of five different genes can cause these defects.
What is a catalase test used to diagnose?
The catalase test is used to differentiate staphylococci (catalase-positive) from streptococci (catalase-negative). The enzyme, catalase, is produced by bacteria that respire using oxygen, and protects them from the toxic by-products of oxygen metabolism.
What is the difference between catalase positive and catalase negative bacteria?
Catalase-positive bacteria include strict aerobes as well as facultative anaerobes, although they all have the ability to respire using oxygen as a terminal electron acceptor. Catalase-negative bacteria may be anaerobes, or they may be facultative anaerobes that only ferment and do not respire using oxygen as a terminal electron acceptor (ie.
What are catalase-negative bacteria?
Catalase-negative bacteria may be anaerobes, or they may be facultative anaerobes that only ferment and do not respire using oxygen as a terminal electron acceptor (ie. Streptococci).
What is the role of catalase in aerobic respiration?
The enzyme, catalase, is produced by bacteria that respire using oxygen, and protects them from the toxic by-products of oxygen metabolism. Catalase-positive bacteria include strict aerobes as well as facultative anaerobes, although they all have the ability to respire using oxygen as a terminal electron acceptor.