Relationship between auxotype, plasmid pattern and susceptibility to antibiotics in penicillinase-producing Neisseria gonorrhoeae.

The relationship between auxotype, plasmid pattern and susceptibility to antibiotics has been studied in 2396 penicillinase-producing Neisseria gonorrhoeae isolated in The Netherlands during 1982 and 1983. The most prevalent auxotypes were proline requiring (Pro-; 44%) and non-requiring with inhibition by phenylalanine (NR Pheni; 39%). The majority (97%) of the Pro- strains carried the 4.5 Mdal resistance plasmid and 99% of the prototrophic strains the 3.2 Mdal plasmid. MICs were determined for cefuroxime, cefotaxime, erythromycin, tetracycline, thiamphenicol and sulphamethoxazole. Pro- isolates were usually less susceptible to antibiotics than prototrophic strains. Evidence was obtained that the level of relative resistance is related to the nutritional requirement as well as the plasmid type.