Sequencing of Neisseria meningitidis penA Gene: the Key to Success in Defining Penicillin G Breakpoints

Testing of susceptibility to penicillin G by E-test and sequencing of an internal fragment of the penA gene were done for 43 meningococcal strains. Those strains for which the MIC was >/=0.094 micro g/ml showed mosaic alleles, so 0.094 micro g/ml is suggested as the penicillin G intermediate breakpoint when E-test is used.