Genetics of Low-Level Antibiotic Resistance in Neisseria Gonorrhoeae

The Genetics of resistance in the gonococcus was studied by mutation and transformation, in laboratory and clinical strains. Low-level penicillin resistance was the result of mutations at penA, ery and penB, which additively resulted in an approximate 100-fold increase in penicillin resistance, to an MIC of 1,0 pg/ml, Mutation at ery resulted in very-low level increases in resistance (two to eight fold) to diverse drugs, detergents and dyes, probably by decreasing cell envelope permeability, Mutations at loci designated envA and envB resulted in increased sensitivity to the same drugs, detergents and dyes, probably by increasing cell envelope permeability. All studied genes were chromosomal, and no evidence was found for drug-inactivating enzymes.