Prevalence and diversity of Clostridium botulinum types A, B, E and F in honey produced in the Nordic countries

A total of 294 honey samples produced in Denmark, Norway and Sweden were studied for the presence of Clostridium botulinum types A, B, E and F by using a multiplex-PCR method. The samples consisted of honeycombs taken directly from beehives, and extracted honey representing several hives or apiaries. The prevalence of C. botulinum showed a significant variation between Denmark, Norway and Sweden, the proportions of positive samples being 26%, 10% and 2%, respectively. The major serotype detected was type B. When analysed with pulsed-field gel electrophoresis (PFGE) using restriction enzyme SacII, the 24 strains isolated produced eight different PFGE patterns. At a similarity level of 95%, four clusters were produced, three of which contained 20 of the 24 analysed strains. One of the clusters included isolates from both Denmark and Norway.