ISOLATION AND PROPERTIES OF BACTERIOLYTIC ENZYME-PRODUCING COCCI FROMTHE HUMAN MOUTH

One-hundred-and-one bacteriolytic enzyme-producing organisms were isol ated from various sites of the mouth. All were non-hemolytic, Gram-pos itive, and chain-forming cocci. Ninety-one strains, like the reference strains of Streptococcus defectivus and S. adjacens, were dependent o n pyridoxal for growth and produced a chromophore. The Rapid ID32 STRE P system speciated these isolates as S. defectivus, S. adjacens or Gem ella morbillorum. The remaining 10 bacteriolytic isolates were pyridox al-independent and 8 belonged to S. intermedius. Some pyridoxal-indepe ndent S. intermedius reference strains including ATCC27335(T) and all group D Enterococcus strains tested were also bacteriolytic. Thus, bac teriolytic enzyme production is common to nutritionally variant strept ococci but not unique to S. defectivus and S. adjacens. The nutritiona lly variant strains generally had arylamidases but not alkaline phosph atase. The S. defectivus strains produced alpha- and beta-galactosidas es (biotype 1) whereas the S. adjacens strains generally produced N-ac etyl-beta-glucosaminidase and some had beta-glucuronidase but others d id not (biotypes 2 and 3). The G. morbillorum strains had no detectabl e activity of these glycosidases (biotype 4) but produced a chromophor e and an arginine dihydrolase, exhibiting a physiological profile atyp ical of the Gemella species. This indicates the possible presence of a n additional phenotypic group or a new species among the nutritionally variant streptococci.