PCR AMPLICON RESTRICTION-ENDONUCLEASE ANALYSIS OF THE CHROMOSOMAL DHPS GENE OF NEISSERIA-MENINGITIDIS - A METHOD, FOR STUDYING SPREAD OF THE DISEASE-CAUSING STRAIN IN CONTACTS OF PATIENTS WITH MENINGOCOCCAL DISEASE

We tested two sets of primers derived from the dhps gene of Neisseria meningitidis for the amplification of meningococcal DNA by PCR, Both t he NM1-NM6 primers and the NM3-NM6 primers amplified dhps DNA from all of the meningococci included in the study, resulting, in most cases, in amplicons of 0.70 and 0.23 kb, respectively. Also, dhps DNAs of N. gonorrhoeae and some commensals were amplified but Haemophilus influen zae, Streptococcus pneumoniae, and Escherichia coli DNAs were not. By PCR amplicon restriction endonuclease analysis (AREA) of the larger am plicon, we could differentiate between individual strains of N. mening itidis, Following two cases of meningococcal disease, we used PCR AREA to identify healthy contacts carrying the disease-causing strain, We conclude that PCR AREA is a useful method for meningococcal strain dif ferentiation and that it has potential as a method for studying the sp read of a disease-causing strain in an affected population. The method is quicker and easier to perform and interpret than chromosomal DNA f ingerprinting.