Aerococcus suis

Aerococcus suis is a species of Gram-positive coccoid bacterium in the family Aerococcaceae. It was first isolated from a pig in Spain with meningitis and formally described in 2007. A. suis is an alpha-hemolytic, catalase-negative bacterium and a potentially opportunistic pathogen of swine.

Taxonomy

Aerococcus suis was described by Vela et al. in 2007 based on isolates from pigs with clinical infections in Spain. The species name is derived from the Latin word suis, meaning "of a pig." The type strain is 1821/02^T. It is phylogenetically related to Aerococcus viridans and Aerococcus urinaeequi, but differs from them based on 16S rRNA gene sequence, phenotypic traits, and biochemical profiles.
An emended description of the species was published in 2014 to clarify phenotypic characteristics and differentiate it from other species within the genus.

Morphology

Aerococcus suis cells are Gram-positive, spherical cocci that typically form tetrads or clusters. Colonies on blood agar are small, non-pigmented, and display alpha-hemolysis after 24 hours at 37 °C. The species is non-motile, non-spore-forming, and catalase- and oxidase-negative. It is facultatively anaerobic and tolerates 6.5% NaCl and pH 9.6.