OBJECTIVEWe developed a multiplex polymerase chain reaction (PCR) method for detection, identification and sero-grouping strains of N. meningitidis.

METHODSThe gene of crgA was selected for detection and identification of N. meningitidis and the 230 bp of crgA fragments were amplified. The genes of siaD and orf-2 were used for sero-grouping. With this technology, N. meningitidis of serogroup A,B,C,Y and W135 can be differentiated from the specific fragment 400 bp,450 bp,250 bp, 120 bp,120 bp.

RESULTSThis multiple PCR method seemed to be more sensitive than latex agglutination. We used this method to detect 61 isolates of N. meningitidis and the 230 bp of crgA fragments were amplified. No positive results were obtained from on 4 strains of non-N. meningitidis. It seemed that the PCR method which was based on crag, was specific in detecting N. meningitidis. The 55 strains of N. meningitidis could be grouped into A,B,C,Y and W135 by this multiplex PCR. No gene fragment was synthesized for the other serogroups of N. meningitidis. No cross-reaction was observed for other bacterial species. 4 samples of meningococcal meningitis patients were detected by the multiplex PCR and two of them were positive with 400 bp band,representing serogroup A of N. meningitidis but all were negative to culture and latex agglutination. 18 samples of Japanese (B) encephalitis patients were also detected by multiplex PCR and no positive result was obtained which was consistent to the finding from culture and latex agglutination.

CONCLUSIONThis multiplex PCR method showed its potential in clinical diagnosis and epidemiological investigation.