Recovery of labeled A. actinomycetemcomitans strains in plaque. (A) All 5 primates in the RhAa-ltxP530 group showed colonization, while only 3 in the RhAa3 group colonized at week 4. (B) The level of recovery was significantly higher in the RhAa-ltxP530 group vs. RhAa3 at week 2 (P = 0.03) but not in week 4, illustrating the difference between early attachment and growth and persistence. No strains from the RhAa-VS2 strain were recovered in any time period (SI Appendix, Fig. S1, colonization at 1, 2, and 4 wk). CFU, colony-forming unit.