Genetic diversity of penicillin-binding protein 2 genes of penicillin-resistant strains of Neisseria meningitidis revealed by fingerprinting of amplified DNA

Abstract

A 2-kilobase fragment containing the penicillin-binding protein 2 gene (penA) was amplified by using the polymerase chain reaction with DNA prepared from 35 penicillin-resistant strains of Neisseria meningitidis isolated in England, Ireland, and Spain (MICs, 0.16 to 1.28 micrograms of benzylpenicillin per ml) and from 10 penicillin-susceptible strains (MICs, less than or equal to 0.04 micrograms of benzylpenicillin per ml). The penA genes were digested with HpaII or TaqYI; and the resulting fragments were end-labeled, fractionated on a polyacrylamide gel, and autoradiographed, to produce gene fingerprints. The fingerprints of the penA genes of the 10 penicillin-susceptible strains were identical. In contrast, the fingerprints of the penA genes of all but two of the penicillin-resistant strains differed markedly from those of the penicillin-susceptible strains. The altered penA genes of group B penicillin-resistant strains were very diverse, and 14 different fingerprints were found among the 15 strains that we examined. The penA genes of the 19 resistant group C strains were less diverse, and two major fingerprint patterns predominated.