Streptococcus is a genus of coccus (spherical) Gram-positive bacteria belonging to the phylum Firmicutes and the order Lactobacillales (lactic acid bacteria). Cell division in this genus occurs along a single axis in these bacteria, thus they grow in chains or pairs, hence the name—from Greek στρεπτός streptos, meaning easily bent or twisted, like a chain (twisted chain). (Contrast this with staphylococci, which divide along multiple axes and generate grape-like clusters of cells.) Most are oxidase-negative and catalase-negative, and many are facultative anaerobes.