Polygenes and Modifier Genes for Tetracycline and Penicillin Resistance in Neisseria gonorrhoeae

The genetic basis for spontaneous resistance to tetracyline (Tet) and penicillin (Pen) in Neisseria gonorrhoeae was investigated. Tet and pen are polygenes which confer small but distinct levels of resistance to Tet and Pen, respectively. Mtr is a multiple-drug resistance polygene which increases resistance to Tet and Pen (as well as to other unrelated antibiotics). Tern is a modifier gene affecting resistance to Tet and Pen. Pem is a modifier gene for Pen resistance, The following gene combinations code for resistance to five antibiotics: tet, mtr and tern for Tet; pen, mtr, pem and tern for Pen; tet, tem and rntr for doxycycline; pen and pern for ampicillin; pen, pern and mtr for nafcillin