IREB2 and periodontitis: The iron acquisition genes fyuA and irp2, and the protectins ompT and KpsMT were prevalent among the strains of phylogroup B2 in patients with moderate periodontitis (p < 0.05, Table 2), while the frequency of the feoB and traT genes was similar between the phylogroups of the strains isolated from patients with the three diagnoses (p < 0.05).