IREB2 and gingivitis: Our results showed that after infection of the human cell line A549 with E. coli strains isolated from gingivitis patients, increased expression of genes associated with adhesion (fimH and iha), iron acquisition (irp-2, feoB and fyuA), and protectins (tratT) correlated with the presence of genes encoding resistance to sulfonamide (sul-2), beta-lactams (blaTEM), tetracycline (tet(A)), the Mar locus (marR-marO), and disinfectants (qacEA1) (Table 3).