RAPID IDENTIFICATION OF PATHOGENIC NEISSERIAS USING THE IDENTICULT-NEISSERIA TEST

A rapid enzymatic method using chromogenic substrates for the rapid id entification of pathogenic neisseria (Identicult-Neisseria, Scott Labo ratories Inc., CA, USA) was tested in parallel with the rapid carbohyd rate utilization test (RCUT) and the Phadebact Monoclonal GC Test agai nst 198 consecutive clinical isolates of oxidase-positive Gram-negativ e diplococci (118 Neisseria gonorrhoeae, 76 N. meningitidis and four N . lactamica). On initial testing the Identicult-Neisseria gave a 95% o verall concordance (97.5% N. gonorrhoeae, 90.8% N. meningitidis) with the RCUT and Phadebact tests; the corresponding figures after repeat t esting were 98% overall concordance (98.3% N. gonorrhoeae, 97.4% N. me ningitidis). Two of the three strains of N. gonorrhoeae mis-identified as N. meningitidis on primary testing were also mis-identified on rep eat testing. Seven strains of N. meningitidis were mis-identified on i nitial testing (six as Moraxella catarrhalis and one as N. lactamica) and two on repeat testing (both as Mor. catarrhalis). We conclude that the Identicult-Neisseria is not sufficiently reliable for the culture confirmation of gonococci and meningococci.