GENETIC LINKAGE BETWEEN SEROGROUP SPECIFICITY AND ANTIBIOTIC RESISTANCE IN NEISSERIA GONORRHOEAE

Abstract

Statistically significant differences were previously demonstrated in antibiotic susceptibility between gonococcal strains of the recently described W serogroups, W I, W II and W III. Strains of serogroup W I were almost always sensitive to penicillin and other antibiotics, while those of the W II and W III serogroups showed a higher incidence of decreased susceptibility. Transformation experiments were therefore undertaken with an antibiotic sensitive serogroup W I gonococcal strain as recipient and a multiresistant W II strain as DNA donor. Transformants with increased resistance to penicillin and several other antibiotics as compared with the recipient acquired the same serogroup specificity as the W II donor. With one of these W II transformants as donor and the sensitive W I strain as recipient, all transformants acquired the same antibiotic susceptibility pattern and the same serogroup as the donor. SDS-PAGE [sodium dodecyl sulfate-polyacrylamide gel electrophoresis] performed on Sarkosyl-extracted outer membrane proteins from donor, recipient and some transformants showed an increase in the MW of the Protein I of the outer membrane of the W II transformants as compared with that of the recipient strain. In rocket-line and crossed-line immunoelectrophoresis, the W II transformants could not be distinguished from the W II donor strain. A genetic linkage between antibiotic multiresistance and serogroup W II specificity was thus shown. This agrees with the demonstrated higher incidence of W II strains with increased antibiotic resistance as compared with that of serogroup W I strains.