<i>futA</i> and <i>futB</i> genotypes of subisolates after 50 <i>in vitro</i> passages with a small bottleneck.

1fut allele at locus, based on sequencing of 200 bp at the 5′ of gene. The types A and B are referred to the genetic sequence present at the corresponding locus in strain 67:21. 2Number of C-residues in 5′ homopolymeric tract and reading frame of the gene (+ in frame, − out of frame) 3Number of C-terminal heptad-repeats