Polymorphic sites in the leukotoxin promoter region of serotype b isolates (n = 41).

The leukotoxin promoter sequence of the isolates was compared with the corresponding sequence of the reference strain Y4 (accession number HAU51861). Y4 sequence was identical to ST 3.ST (sequence types). Position -1 corresponds to the first nucleotide upstream of the start codon for lkt. Position – 1109 corresponds to the first nucleotide after the terminal codon of glyA.*Deletion of a single nucleotide at this position.