1 / 7

Ex. 5-4 Catalase test

Ex. 5-4 Catalase test. MCB 1000 Lab. Prof. Meléndez. Catalase test.

margot
Download Presentation

Ex. 5-4 Catalase test

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ex. 5-4 Catalase test MCB 1000 Lab. Prof. Meléndez

  2. Catalase test • The catalase test is used to detect the presence of the enzyme catalase in bacteria. Catalase serves to neutralize the bactericidal effects of hydrogen peroxide. Its concentration in bacteria has been correlated with pathogenicity. This enzymatic test is essential in the scheme of identification for gram-positive organisms and certain gram-negative organisms. It is a primary test used in the differentiation of staphylococci and streptococci.

  3. Catalase test • TheoryThe catalase enzyme serves to neutralize the bactericidal effects of hydrogen peroxide . Catalase expedites the breakdown of hydrogen peroxide (H2O2- (toxic) into water (H2O) and oxygen(O2) 2H2O2 + Catalase → 2H2O + O2(gas bubbles) • This reaction is evident by the rapid formation of bubbles

  4. Catalase test • The catalase test facilitates the detection of the enzyme catalase in bacteria. It is essential for differentiating catalase-positiveMicrococcaceae from catalase-negativeStreptococcaceae. • The catalase test is also valuable in differentiating aerobic and obligate anaerobic bacteria, as anaerobes are generally known to lack the enzyme . In this context, the catalase test is valuable in differentiating aerotolerant strains of Clostridium, which are catalase negative, from Bacillus, which are catalase positive

  5. Slide catalase test results. Hydrogen peroxide was added directly to the culture on a microscope slide. A positive reaction produced by Staphylococcus aureusisindicated by bubbling; a negative reaction produced by Streptococcus pyogenesis indicated by lack of bubbling. (Karen Reiner, Andrews University, Berrien Springs, MI)

  6. Practice questions • Read lab. manual pages 243-246 and fill out following chart: Determine if situation on first column will cause a false positive or a false negative. Explain why?

  7. References • http://www.microbelibrary.org/index.php/library/laboratory-test/3226-catalase-test-protocol • Leboffe, Michael J. , and Burton E. Pierce. Microbiology Laboratory, Theory and application: (brief edition). Colorado: Morton Publishing Company, 2008.

More Related