The basic local alignment search tool showed that the 16S rRNA sequence of NHP1 had the highest similarity with the gene of K.denitrificans (Fig. 4A). The 1468 sequence alignment of NHP1 and K. denitrificans ATCC33394 (type-strain) had 99% identity (notshown). NHP1 differs in its sequence by only 3 bases from UB-294,an oral isolate of K. denitrificans [23] and by 5 bases fromATCC33394 (Fig. 4B). Since a phylogenetic tree derived from the distant matrix by using the neighbor joining method [28] formed a tight cluster on the tree (Fig. 4A), NHP1 was diagnosed as K. denitrificans.