Bacilli

Bacillus

Bacillus is a genus of Gram-positive rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods. These characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera.

Streptococcus

Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs.
staphylococcus

Staphylococci are spherical Gram-positive bacteria, which are immobile and form grape-like clusters. They form bunches because they divide in two planes as opposed to their close relatives streptococci which, although they are similarly shaped, form chains because they divide only in one plane. Staphylococci are facultative anaerobes.

Listeria

Listeria monocytogenes is commonly found in soil, stream water, sewage, plants, and food.Listeria are known to be responsible for listeriosis, a rare but potentially lethal food-borne infection.