IDENTIFICATION OF GROUP VS116 STRAINS AMONG BORRELIA-BURGDORFERI SENSU-LATO GROWN FROM THE HARD TICK, IXODES-RICINUS (LINNAEUS, 1758) BY PCR-COUPLED RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSIS

A total of 67 spirochetal isolates grown from the hard tick, Ixodes ri cinus were analysed by PCR amplification of the spacer region between two conserved structures, the 3' end of the 5S rRNA and the 5' end of the 23S rRNA genes of Borrelia burgdorferi sensu late. A 246-255 bp am plicon was generated from 13 reference strains of B. burgdorferi sensu late representing the three major genospecies, B. burgdorferi sensu s tricto, B. garinii, and B. afzelii, and from all 67 spirochetal isolat es from ticks but not from B. hermsii. As could be confirmed by DNA se quence analysis, restriction fragment length polymorphism (RFLP) analy sis of the PCR product after cleavage with DraI and MseI distinguished between the three major genospecies: out of the 67 B. burgdorferi sen su late isolates from ticks, 27 (40.3%) were typed as B. burgdorferi s ensu stricto including five isolates with a unique DraI or MseI patter n. 26 isolates (38.8%) were typed as B. garinii and 6 (9.0%) as B. afz elii, respectively. A group of eight isolates (11.9%) displayed a uniq ue MseI pattern identical to that described for a putative new Europea n genospecies of Borrelia burgdorferi sensu late designated VS116. DNA sequences of the PCR product of seven of these isolates tested were b y less than 88.5% identical with the established European major genosp ecies but shared 98% to 100% homology with that of database-derived se quences of strain VS116 from Switzerland and strain UK from England wh ich are both representatives of the European genomic group VS116.