Disease and carrier isolates of Neisseria meningitidis from two regions of the United States were typed by the arbitrarily primed polymerase chain reaction (PCR), or random amplified polymorphic DNA (RAPD), method. This technique generates strain-specific arrays of amplified DNA fragments using low-stringency PCR with single, arbitrarily chosen primers. Each of 3 disease isolates and 7 of 11 carrier isolates from an outbreak at the University of Connecticut were indistinguishable using each of 4 primers. In contrast, 22 other isolates (the remaining 4 carrier isolates plus 18 disease and carrier isolates from Connecticut, Illinois, and Missouri) were divided into 18 sets using the same 4 primers. This outcome supports the view that disease isolates from an outbreak may reflect sporadic invasive progression by a strain that also frequently causes asymptomatic colonization. Our results show that RAPD tests provide a sensitive and efficient means of distinguishing genetically different meningococcal strains and that they should facilitate clinical, epidemiologic, and population genetic studies of this important pathogen.
Bacterial Typing Techniques Base Sequence