[1] Vrije Univ Amsterdam, Med Ctr, Ctr Diabet, NL-1007 MB Amsterdam, Netherlands
[2] Univ Maastricht, Dept Human Biol, Maastricht, Netherlands
[3] Wageningen Univ, Microbiol Lab, Wageningen, Netherlands
[4] Univ Helsinki, Dept Vet Biosci, Helsinki, Finland