THE DETECTION OF PENICILLIN INSENSITIVITY IN NEISSERIA-MENINGITIDIS BY POLYMERASE-CHAIN-REACTION

Strains of penicillin-sensitive and -insensitive Neisseria meningitidi s were examined using a range of polymerase chain reaction (PCR) prime rs directed at the meningococcal penicillin-binding protein 2 gene. DN A from isolates whose penicillin MIC was <0.2 mg/L yielded a product o f the expected size with all the primers, but many amplification patte rns were seen with DNA from isolates whose MIC was above this level. A ll strains whose MIC was >0.25 mg/L failed to produce a product of the expected size with at least one of the primers used. The changes seen in penicillin-insensitive strains were consistent with horizontal gen e transfer from Neisseria flavescens in some isolates, although the so urce for others remains unknown. PCR-based methods for the detection o f antibiotic resistance are becoming increasingly important with the e xpanding use of molecular techniques for bacteriological diagnosis.