TABLE 1

Effects of pH 5.0 THB versus THB on biofilm formation by different GBS serotypesa

SerotypeMean CV assay valueNo. (%) of strains with CV assay values of >3MeanpH 5.0 THB/meanTHBMean differenceAdjusted P value
pH 5.0 THBTHB
Ia0.740.131 (8.6)5.690.610.0481
Ib0.520.170 (0)3.060.350.9851
II0.370.130 (0)2.850.240.9952
III1.580.2135 (22.4)7.521.37<0.0001
IV0.660.140 (0)4.710.520.9740
V0.880.144 (7.0)6.290.740.0083
VIII1.050.200 (0)5.250.850.9864
IX0.470.110 (0)4.270.360.9938
Nontypeable0.740.210 (0)3.520.530.6693
III (ST-17)2.200.2233 (36.3)10.001.98<0.0001
III (non-ST-17)0.550.182 (3.1)3.060.370.3184
  • a GBS biofilm formation was quantified by CV staining. Note that the percentage of biofilm formers with CV assay values of >3 is referred to the number of strains of each serotype (e.g., 156 for serotype III). Significant increments of mean CV assay values are in bold.