Background: Neisseria meningitidis  is a leading pathogen of meningococcal disease in humans worldwide. Multiple cross displacement mplification (MCDA) combined with nanoparticles-based lateral flow biosensor (MCDA-LFB) has been reported for the rapid detection of several bacterial pathogens in recent years. Here, therefore we developed an MCDA-LFB assay for the rapid detection of N. meningitis .
Methods: A set of 10 primers specifically to recognize 10 different regions of the ctrA  gene of N. meningitidis  were designed. MCDA was developed and combined with a LFB to detect the ctrA  gene of N. meningitidis . The reaction time and temperature condition for the MCDA-LFB were optimized and then the MCDA-LFB was applied to detect the DNA from clinical samples.
Results: MCDA-LFB assay was successfully established for the detection of N. meningitidis  based on the ctrA  gene. The MCDA assay was optimized at 64°C for only 35 mins and the products of amplification were directly sensed by LFB. The whole operation, including DNA template preparation (∼20 mins), MCDA reaction (35 mins) and results interpretation (∼2 mins) could be finished in no more than 60 mins. The detection limit was as low as 10 fg/reaction (around 3 CFUs/reaction) of pure N. meningitidis  DNA, with no cross-reaction with other bacterial DNA.
Conclusion: The MCDA-LFB techniques developed in the present study are an effective tool for the rapid detection of N. meningitidis , especially in resource-poor countries in meningococcal disease epidemic period.
Keywords: Neisseria meningitidis , multiple cross displacement amplification, lateral flow biosensor, MCDA-LFB, limit of detection