Demonstration of genome DNA diversity of strains of urease-positive thermophilic Campylobacter isolated from the natural environment by pulsed-field gel electrophoresis analysis

Pulsed-field gel electrophoresis (PFGE) analysis was carried out after sepa rate digestion with Apa I, Sal I and Sma I of the genomic DNA from sixteen isolates of urease-positive thermophilic Campylobacter (UPTC) obtained from the natural environment, namely from oysters and mussels, in Northern Irel and. Five NCTC strains previously isolated in England were used for the ana lysis. Although the eight isolates of UPTC in Northern Ireland and a strain of UPTC in England showed that one or no fragments appeared after digestio n with Apa I around 1,900 to 1,640 kb region of the gel, Apa I was shown to cut the genomic DNA from all of the other twelve strains of UPTC and Sal I and Sma I from all of the 21 strains in a distinctly different and disting uishable manner. Consequently, the present study clearly demonstrated that the sixteen isolates of UPTC in Northern Ireland and the five strains in En gland gave the diversity of the genomic DNA by using PFGE. Some strains of UPTC examined were shown to carry genomes from 1.5 to 1.9 Mb in length, thu s the heterogeneous profiles of PFGE and the length of the genomes are thou ght to occur among the isolates of UPTC in Northern Ireland, as well as amo ng the five reprensentative strains of UPTC from NCTC.