FIG. 2.

Strain FA1090Cm^R has an Opa-dependent advantage in vivo over the wild-type strain. Data points correspond to the frequency of Cm^r colonies isolated from individual mice following inoculation with the following mixtures: (A) Cm^s and Cm^r Opa⁻ variants (control group) (data are combined from four experiments [n = 5 to 9 mice per experiment; total n = 30]); (B) OpaI Cm^r and Opa⁻ Cm^s variants (data are combined from three experiments [n = 5 or 6 mice/experiment; total n = 16]); (C) OpaB Cm^r and Opa⁻ Cm^s variants (n = 8). The frequency of FA1090Cm^R gonococci among the total number of CFU in the inocula ranged from 0.07 to 0.19 for all experiments. The frequency of Cm^r vaginal isolates from mice inoculated with Cm^r Opa⁺ variants (OpaI or OpaB) compared to that recovered from mice inoculated with Opa⁻ Cm^s and Opa⁻ Cm^r gonococci is shown (P values of <0.001 and <0.008, respectively; repeated measures analysis of variance). A mixed-model approach (SAS PROC MIXED, version 8.0) was used to accommodate animals for which data were collected on fewer than three days. The main effect of group was evaluated using Tukey's adjustment for multiple comparisons.