Distribution of Streptococcus mitis biovar 1 phenotypes on shedding and non-shedding oral surfaces of human infants during the first year of life

Figures & data

Table I.  Division of S. mitis biovar 1 into four groups based on production of neuraminidase, β1-N-acetylglucosaminidase and β1-N-acetylgalactosaminidase and their distribution on cheeks, tongue and teeth.

	Numbers (and percentages) of isolates of each phenotype obtained from each surface
Group	Total	Cheek	Tongue	Tooth	Neuraminidase production	β-N-acetylglucosaminidase production	β-N-acetylgalactosaminidase production	Amylase binding (% positive)	IgA1 protease (% positive)
1	233	104 (45)	11 8(51)	11 (5)	–	–	–	36	80
2	685	233 (34)	384 (56)	68 (10)	–	+	+	46	12
3	1,172	588 (50)	559 (48)	25 (2)	+	–	–	39	39
4	1,054	565 (54)	387 (37)	102 (10)	+	+	+	38	91

Table II.  Preference of phenotypes of S. mitis biovar 1 for buccal mucosa, tongue and teeth.

	Phenotype			Site
Group	Neuraminidase	β1-N-acetylglucosaminidase	β1-N-acetylgalactosaminidase	Buccal mucosa, tongue, teeth	p value
1	–	–	–	No preference for any site	NS
2	–	+	+	No preference for any site	NS
3	+	–	–	Buccal mucosa > teeth tongue > teeth	<0.01 0.01
4	+	+	+	Buccal mucosa > teeth tongue > teeth	0.001 0.01

Figure 1.  Percentage of total S. mitis biovar 1 by phenotype, site and visit. Visits 1–9 correspond to 1–3 days, 2 weeks, 4 weeks and 2, 4, 6, 8, 10, and 12 months post partum, respectively. Group 1 (0-0-0 phenotype); group 2 (0-1-1 phenotype); group 3 (1-0-0 phenotype); group 4 (1-1-1 phenotype).

Figure 2.  Percentage of total S. mitis biovar 1 by site, phenotype and visit. Visits 1–9 correspond to 1–3 days, 2 weeks, 4 weeks and 2, 4, 6, 8, 10, and 12 months post partum, respectively. Dentate infants were not sampled at visit no. 9. Group 1 (0-0-0 phenotype); group 2 (0-1-1 phenotype); group 3 (1-0-0 phenotype); group 4 (1-1-1 phenotype).