 Many infections caused by "peptostreptococcus" bacteria are synergistic.Bacterial synergy, the presence of which is determined by mutual induction of sepsis enhancement, increased mortality, increased abscess inducement, and enhancement of the growth of the bacterial components in mixed infections, is found between anaerobic gram-positive cocci and their aerobic and anaerobic counterparts.The ability of anaerobic gram-positive cocci and microaerophilic streptococci to produce capsular material is an important virulence mechanism, but other factors may also influence the interaction of these organisms in mixed infections.