Research progress of Streptococcus anginosus group as opportunistic pathogens
Streptococcus anginosus group(SAG)used to be considered as normal oral flora.With the advance-ment of diagnostic techniques,an increasing number of case reports confirm that SAG group can be an opportunistic pathogen causing a series of fatal infection.Therefore,this article reviews the diseases caused by SAG as opportu-nistic pathogens and its related pathogenic mechanisms.