nspA Gene as a specific genetic marker for detection of Neisseria meningitidis causing bacterial meningitis.

Bacterial meningitis caused by Neisseria meningitidis which causes human brain meninges damage, is generally diagnosed from patient cerebrospinal fluid through microscopy, immunological assays, biochemical test, PCR, microarray and biosensors. However, these methods are expensive, time-consuming or non-confirmatory due to certain limitations. A quick PCR based method was developed for detection of bacterial meningitis caused by N. meningitidis using specific primers based on amplification of virulence nspA (Neisseria surface protein A) gene partial sequence (202 bp). The nspA gene amplicon could be used as a genetic marker for minimum detection of 10 ng genomic DNA (G-DNA) of N. meningitidis with high sensitivity only in 80 min, which is least time reported for the confirmation of the disease. However, the lower detection limit was found as low as 1.0 ng G-DNA, but with less sensitivity. The cross-reactivity of the genetic marker was also studied with other possible pathogens. A comparison with the presently available detection methods and our method was also done using patient samples.

Prokaryotic expression of Neisseria gonorrhoeae NspA and its antigenicity / 中华微生物学和免疫学杂志

Objective To develop fast detection techniques for the diagnosis of gonococcal infections.Methods Prokaryotic expression vector for Neisserial surface protein A (NspA) was constructed using the NspA gene cloned by PCR.Mice were immunized with the renatured recombinant NspA (rrNspA)to prepare antibodies against NspA.Western blot and ELISA was used to analyze the binding of NspA antibodies to lysate of gonococcal cells or to intact gonococci.Results NspA antibodies that were prepared by the rrNspA expressed in E.coli could bind to rrNspA,the natural NspA existing in gonococcal cells,or intact gonococci.Conclusion RrNspA and its antibodies have potential value in developing fast diagnostic kits for gonococcal diseases.