Evidence for a genetically stable strain of Campylobacter jejuni

The genetic stability of selected epidemiologically linked strains of Campy lobacter jejuni during outbreak situations was investigated by using subtyp ing techniques. Strains isolated from geographically related chicken flock outbreaks in 1998 and from a human outbreak in 1981 were investigated. Ther e was little similarity in the strains obtained from the different chicken flock outbreaks; however, the strains from each of three chicken outbreaks, including strains isolated from various environments, were identical as de termined by fla typing, amplified fragment length polymorphism (AFLP) analy sis, and pulsed-field gel electrophoresis, which confirmed the genetic stab ility of these strains during the short time courses of chicken flock outbr eaks. The human outbreak samples were compared with strain 81116, which ori ginated from the same outbreak but has since undergone innumerable laborato ry passages, Two main AFLP profiles mere recognized from this outbreak, whi ch confirmed the serotyping results obtained at the time of the outbreak. T he major type isolated from this outbreak (serotype P6:L6) was exemplified by strain 81116. Despite the long existence of strain 81116 as a laboratory strain, the AFLP profile of this strain was identical to the profiles of a ll the other historical P6:L6 strains from the outbreak, indicating that th e genotype has remained stable for almost 20 years. Interestingly, the AFLP profiles of the P6:L6 group of strains from the human outbreak and the str ains from one of the recent chicken outbreaks were also identical. This sim ilarity suggests that some clones of C. jejuni remain genetically stable in completely different environments over long periods of time and considerab le geographical distances,