MOLECULAR ANALYSIS OF DICHELOBACTER-NODOSUS ISOLATED FROM FOOTROT IN SHEEP IN MALAYSIA

Pulsed field gel electrophoresis analysis of genomic DNA was used to i nvestigate genetic diversity among Dichelobacter nodosus from footrot in sheep in Malaysia. Twelve Dichelobacter nodosus strains isolated fr om lesion materials from infected sheep were confirmed as Dichelobacte r nodosus by polymerase chain reaction technique using the species-spe cific Dichelobacter nodosus 16S RNA sequence Ac and C as primers. Puls ed field gel electrophoresis banding profiles using restriction enzyme s ApaI (5'GGGCCC3'), SfiI (5'GGCCNNNNNGGCC3') and SmaI ('5CCCGGG3') en abled the 12 Dichelobacter nodosus strains to be differentiated into e ight different PFGE patterns and thus genome-types, with F (coefficien t of similarity) values ranging from 0.17 to 1.0 (ApaI), 0.14 to 1.0 ( SfiI) and 0.22 to 1.0 (SmaI). Strains with origin in different farms w ere shown to have different PFGE patterns (two strains, M7 and M8 were the only exception). On the basis of their PFGE, all field strains us ed in the study differed from the reference strains: Our data revealed that there are several clonal types of Dichelobacter nodosus isolates and indicated that there is probably more than one source of this pat hogen on the farms studied. The study showed that strains of D. nodosu s exhibited considerable genetic diversity using this method and that genomic analysis by pulsed field gel electrophoresis was useful in dis criminating the D. nodosus strains. (C) 1998 Elsevier Science B.V. All rights reserved.