FALSE-POSITIVE DIAGNOSIS OF MENINGOCOCCAL INFECTION BY THE IS1106 PCRELISA

At a time when optimal case ascertainment for meningococcal infection is a high priority, the need for non-culture case confirmation, in par ticular by DNA amplification, is seen as being of vital importance to assist contact management and cluster recognition. A solution hybridis ation assay with colorimetric microtitre plate detection (polymerase c hain reaction-enzyme-linked immunosorbent assay (PCR ELISA)) has been developed using the multicopy insertion sequence IS1106 which had repo rtedly achieved a specificity of 100% and was described as being menin gococcal specific. This PCR ELISA assay was evaluated on specimens fro m over 5000 patients at the national Meningococcal Reference Unit (MRU ) between late 1995 and early 1997 and was found to be highly sensitiv e. Insertion sequences, however. are genetically mobile with the abili ty to spread between species and even genera. During the evaluation pe riod of the IS1106 PCR ELISA a number of false positives proved to be caused by organisms other than N. meningitidis were recorded resulting in the withdrawal of this assay as a front line screening assay for r outine confirmation of meningococcal infection. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V .