Molecular characterisation of human campylobacteriosis in Northern Ireland: evidence of clonal stability.

Background: No study has compared Campylobacter isolates from a human source in Northern Ireland over an extended period of time.
Aim: To investigate the clonal stability of thermophilic campylobacters isolated from acute bacterial enteritis in Northern Ireland from 1992 to 1999.
Methods: Human isolates (n=272), originating from faeces, were characterised at the sub-species level using enterobacterial repetitive intergenic consensus sequence (ERIC2)--random amplification of polymorphic DNA (RAPD) typing.
Results: Thirteen genotypes were identified where three types, namely ERIC A, ERIC C and ERIC I, accounted for 28.3%, 14.3% and 13.6%, respectively. There were no significant associations (p>0.05) between sex, age groupings and year of isolation and ERIC2 genotype, with the exception of ERIC D, which showed a significant decline in isolation with time (p=0.019).
Conclusions: ERIC genotypes were stable over this period, except genotype C which was lost during this time. Previous molecular typing methods showed campylobacters to be heterogeneous but this study suggests that the local human Campylobacter population consists of several common and stable genotypes. This study has established a database of local ERIC2 genotypes. This methodology may allow the establishment of an all-island database of clinical campylobacters that would be valuable in reducing human campylobacteriosis in Ireland.