Yes, it is catalase positive. This is because it is capable of breaking down hydrogen peroxide (H2O2) to give water and oxygen. The presence of bubbles when hydrogen peroxide is added to E. coli on a microscope slide is a phenotypic (observable physical characteristic) proof that it is catalase positive. Vital Tips for Preventing E. coli in Your Home Most strains of E. coli bacteria live in your intestine and are harmless. 2  However, some strains found on raw food and spoiled remains make people very sick. 3  Follow the steps â¦.
Spotting between periods can be a sign that the hormones that regulate your menstrual cycle are âout of sync.â Certain medications, particularly birth control pills, can trigger hormonal fluctuations that lead to spotting.
You should know that these symptoms may be caused by other things besides being pregnant. So the fact that you notice some of these symptoms does not necessarily mean you are pregnant. The only way to tell for sure is with a pregnancy test.his can cause one of the earliest signs of pregnancy -- spotting and, sometimes, cramping. That's called implantation bleeding. It occurs anywhere from six to 12 days after the egg is fertilized.