title: beta-haemolysis and pigment production by the oral bacterium Streptococcus mutans.
abstract: The prevalence of beta-haemolysis and yellow pigmentation among 89 isolates of Streptococcus mutans from human dental plaque and 59 Strep. mutans isolates from positive cultures of human dental root canals were investigated. beta-Haemolytic strains were more frequent among the root-canal isolates (25.4 per cent) than among the dental plaque isolates (12.4 per cent). The distribution of pigment production among beta-haemolytic strains (22 pigmented strains out of 26 strains) and among non-haemolytic strains (5 pigmented strains out of 122 strains) showed a relationship between haemolysin and pigment production. beta-Haemolytic, pigmented strains (biotype c and e and 35-39 per cent guanine plus cytosine) were common in plaque and were the dominant type of Strep. mutans in some plaques. As beta-haemolysis by Strep. mutans was only demonstrated after strict anaerobic growth, whereas pigment production was demonstrated after growth under less anaerobic conditions (candle jar) on sucrose-containing agar plates, the observation of pigment may facilitate a presumptive identification of beta-haemolytic strains of Strep. mutans.
mesh_terms: D003773:Dental Plaque / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology; D006461:Hemolysis; D006801:Humans; D010860:Pigments, Biological / Q000378:metabolism*; D013295:Streptococcus mutans / Q000145:classification / Q000378:metabolism / Q000502:physiology*
chemical_list: D010860:Pigments, Biological