Table 2. List of relative abundance of bacterial groups (%), identified according to the results of the 16S rRNA sequencing. All abundances are based upon the proportional frequency of sequences that could be identified at the genus level, the family level (unclassified genus) and order-level (unclassified family).

Bacteria	healthy control	generalized chronic gingivitis	localized initial periodontitis
Abiotrophia	0.05 (0.00 to 0.55)	0.02 (0.00 to 3.40)	0.11 (0.00 to 7.24)
Actinobacillus	0.04 (0.00 to 1.91)	0.00 (0.00 to 0.33)	0.00 (0.00 to 7.59)
Actinomyces	2.46 (0.27 to 16.13)	1.50 (0.39 to 3.91)	1.49 (0.32 to 6.11)
Aggregatibacter	0.08 (0.01 to 3.18)	0.46 (0.00 to 3.54)	0.07 (0.00 to 3.18)
Atopobium	0.08 (0.00 to 2.60)	0.10 (0.00 to 0.99)	0.14 (0.01 to 1.63)
Bacteroidales	0.01 (0.00 to 0.05)	0.13 (0.01 to 1.95)	0.09 (0.00 to 1.41)
Bulleidia	0.07 (0.00 to 0.64)	0.14 (0.03 to 0.77)	0.20 (0.00 to 1.59)
Campylobacter	0.15 (0.08 to 5.76)	1.04 (0.53 to 2.96)	0.21 (0.05 to 1.63)
Capnocytophaga	0.85 (0.10 to 4.23)	1.85 (0.16 to 4.13)	2.31 (0.15 to 11.56)
Comamonas	0.10 (0.00 to 4.56)	0.01 (0.00 to 0.17)	0.04 (0.00 to 0.33)
Corynebacterium	0.21 (0.02 to 1.22)	2.42 (0.29 to 6.00)	0.47 (0.01 to 5.17)
Desulfovibrionaceae	0.01 (0.00 to 0.58)	0.44 (0.00 to 3.31)	0.16 (0.00 to 1.82)
Dialister	0.03 (0.01 to 0.74)	0.65 (0.12 to 2.85)	0.51 (0.00 to 5.58)
Eikenella	0.08 (0.01 to 0.64)	0.25 (0.04 to 2.65)	0.18 (0.00 to 1.48)
Escherichia	0.63 (0.04 to 26. 51)	0.15 (0.03 to 0. 95)	0.36 (0.01 to 2.78)
Filifactor	0.00 (0.00 to 0.32)	0.57 (0.00 to 6.68)	0.79 (0.00 to 4.07)
Fusobacterium	5.16 (0.39 to 14.97)	10.19 (3.36 to 21.73)	5.04 (1.19 to 30.09)
Gemellaceae	1.50 (0.05 to 6.38)	0.81 (0.30 to 5.90)	2.08 (0.08 to 14.66)
Granulicatella	3.46 (0.07 to 5.49)	0.63 (0.16 to 4.61)	1.38 (0.07 to 7.67)
Haemophilus	1.51 (0.00 to 14.65)	0.42 (0.07 to 10.16)	0.47 (0.01 to 6.52)
Halomonas	0.00 (0.00 to 3.60)	0.00 (0.00 to 0.00)	0.00 (0.00 to 0.29)
Lachnospiraceae	0.16 (0.01 to 6.48)	0.43 (0.00 to 2.91)	0.05 (0.00 to 1.84)
Lautropia	0.15 (0.01 to 2.33)	0.16 (0.02 to 1.28)	0.12 (0.00 to 3.20)
Leptotrichia	1.87 (0.14 to 16.97)	5.28 (0.01 to 19.83)	1.75 (0.03 to 10.59)
Leptotrichiaceae	0.00 (0.00 to 0.12)	0.00 (0.00 to 4.20)	0.00 (0.00 to 1.79)
Megasphaera	0.03 (0.00 to 0.75)	0.03 (0.00 to 2.39)	0.09 (0.00 to 1.19)
Mogibacteriaceae	0.06 (0.00 to 0.76)	1.02 (0.04 to 2.62)	0.90 (0.02 to 3.14)
Neisseria	8.50 (0.03 to 18.18)	0.65 (0.015 to 10.08)	1.84 (0.00 to 24.46)
Oribacterium	0.25 (0.00 to 2.14)	0.13 (0.00 to 0.51)	0.09 (0.00 to 1.45)
Paludibacter	0.05 (0.00 to 0.73)	0.36 (0.00 to 3.86)	0.19 (0.00 to 1.35)
Parvimonas	0.12 (0.00 to 0.60)	0.92 (0.05 to 2.45)	1.15 (0.09 to 3.07)
Peptostreptococcus	0.01 (0.00 to 0.65)	0.28 (0.00 to 1.31)	0.28 (0.00 to 5.47)
Porphyromonas	0.68 (0.02 to 9.74)	4.09 (0.29 to 12.36)	2.92 (0.53 to 32. 2)
Prevotella	3.27 (0.41 to 11.23)	5.75 (0.99 to 28.69)	4.74 (0.28 to 15.26)
Rothia	5.35 (0.13 to 13.30)	0.76 (0.03 to 4. 06)	0.57 (0.02 to 15.28)
Rs-045(Candidatus Saccharibacteria)	0.00 (0.00 to 0.01)	0.58 (0.00 to 4.04)	0.05 (0.00 to 2.67)
Schwartzia	0.00 (0.00 to 0.16)	0.74 (0.07 to 1.32)	0.19 (0.00 to 2.59)
Selenomonas	0.10 (0.00 to 1.85)	4.45 (0.10 to 12.78)	0.49 (0.00 to 9.59)
Streptococcus	31.73 (6.11 to 50.30)	17.51 (4.01 to 34.43)	18.37 (1.66 to 50.40)
Tannerella	0.07 (0.00 to 1.23)	0.69 (0.16 to 2.70)	0.59 (0.00 to 4.66)
Tissierellaceae	0.00 (0.00 to 0.33)	0.09 (0.00 to 3.82)	0.01 (0.00 to 1.22)
TM7-3 (Candidatus Saccharibacteria)	0.41 (0.08 to 21.51)	5.75 (0.75 to 12.09)	3.28 (0.06 to 14.11)
Treponema	0.04 (0.00 to 0.54)	1.13 (0.13 to 4.76)	0.47 (0.00 to 9.57)
Veillonella	3.65 (0.36 to 10.19)	4.66 (0.47 to 11.89)	2.19 (0.00 to 7.64)
Weeksellaceae	0.18 (0.01 to 0.71)	0.09 (0.00 to 1.19)	0.18 (0.00 to 16.10)