Reliability of the detection of meningococcal γ-glutamyl transpeptidase as an identification marker for Neisseria meningitidis

Abstract

Detection of γ-glutamyl transpeptidase (GGT; ggt) activity is one of the useful methods for a specific identification of Neisseria meningitidis. However, we previously happened to isolate a ggt-deficient N. meningitidis strain (NIID113) from a healthy carrier. In this study, in order to re-examine the reliability of the marker, we again investigated the GGT activity of 245 N. meningitidis human isolates and identified two other GGT-defective N. meningitidis isolates besides NHD113. The isolation frequency (1.2%) of ggt mutants among human isolates strongly confirmed the 98.8% reliability of GGT activity as the identification marker for N. meningitidis.