Skip to main content

Table 4 Frequency of genes encoding the alpha (bca) and beta (bac) C proteins, and the protein Rib (rib) among invasive versus colonizing group B streptococcal isolates by serotype.

From: The frequency of genes encoding three putative group B streptococcal virulence factors among invasive and colonizing isolates

  Invasive n (%) Colonizing n (%)
  bca bac rib bca bac rib
Overall freq. 29/100 (29) 20/100 (20) 28/100 (28) 167/360 (46)* 82/360 (23) 72/360 (20)†
By Serotype       
Ia 0/33 (0) 0/43 (0) 0/33 (0) 18/71 (25)* 6/71 (8)† 1/71 (1)
Ib 12/12 (100) 11/12 (92) 0/12 (0) 29/42 (69)* 32/42 (76) 3/42 (7)
II 8/15 (53) 2/15 (13) 5/15 (33) 25/45 (56) 10/45 (22) 15/45 (33)
III 0/23 (0) 6/23 (26) 23/23 (100) 5/44 (11)† 4/44 (9)† 39/44 (89)†
IV 0/0 (0) 0/0 (0) 0/0 (0) 1/2 (50) 1/2 (50) 0/2 (0)
V 8/15 (53) 1/15 (7) 0/15 (0) 51/76 (67) 10/78 (13) 6/78 (8)
VI 0/0 (0) 0/1 (0) 0/0 (0) 5/6 (83) 0/6 (0) 0/0 (0)
VIII 0/0 (0) 0/0 (0) 0/0 (0) 1/1 (100) 1/1 (100) 0/0 (0)
NT 0/0 (0) 0/10 (0) 0/0 (0) 23/41 (56) 13/41 (32) 5/41 (12)
  1. Note: Serotype data are missing for 30 strains.
  2. *The difference in the gene frequency between invasive and colonizing populations is statistically significant at p < .05 using the Chi square test.
  3. †Marginally significant Chi square estimate (.06 < p < .10)