DIFFERENTIATION OF CAMPYLOBACTER-JEJUNI SEROTYPE O-19 STRAINS FROM NON-O-19 STRAINS BY PCR

Guillain-Barre syndrome (GBS), a neurologic disease characterized by a cute paralysis, is frequently preceded by Campylobacter jejuni infecti on. Serotype O19 strains are overrepresented among GBS-associated C. j ejuni isolates. We previously showed that all O19 strains tested were closely related to one another by randomly amplified polymorphic DNA ( RAPD) and restriction fragment length polymorphism analyses. RAPD anal ysis demonstrated a 1.4-kb band in all O19 strains tested but in no no n-O19 strains. We cloned this O19-specific band; nucleotide sequence a nalysis revealed a truncated open reading frame with significant homol ogy to DNA gyrase subunit B (gyrB) of Helicobacter pylori. PCR using t he random primer and a primer specific for gyrB showed that in non-O19 strains, the random primer did not recognize the downstream gyrB bind ing site. The regions flanking each of the random primer binding sites were amplified by degenerate PCR for further sequencing. Although the random primer had several mismatches with the downstream gyrB binding site, a single nucleotide polymorphism 6 bp upstream from the 3' term inus was found to distinguish O19 and non-O19 strains. PCR using 3'-mi smatched primers based on this polymorphism was designed to differenti ate O19 strains from non-O19 strains, When a total of 42 (18 O19 and 2 4 non-O19) strains from five different countries were examined, O19 st rains were distinguishable from non-O19 strains in each case. This PCR method should permit identification of O19 C. jejuni strains.