Which gram positive cocci are catalase positive

Microorganisms that can ferment mannitol create acidic byproducts, which decrease the pH of the medium and cause the pH indicator, phenol red, to turn yellow. Gram-positive cocci are often isolated from clinical samples.

Catalase is an enzyme that converts hydrogen peroxide to water and oxygen gas. The test is easy to perform; bacteria are simply mixed with H 2O 2.

If bubbles appear due to the production of oxygen gas the bacteria are catalase positive. If no bubbles appear, the bacteria are catalase negative. Staphylococcus and Micrococcus spp. A negative result is no bubbles or only a few scattered bubbles. Dispose of your slide in the biohazard glass disposal container. Diagnostic Microbiology, 9th ed. Louis, Mo. Isenberg, H. Clinical Microbiology Procedures Handbook, Vol. Washington DC. The majority of the isolates were identified as Staphylococcus spp.

A great variety of staphylococcal strains were found within the different species at any sampling time. In addition, enterotoxin D was confirmed in the nonidentified strains.