Fig 1.

Examples of various cross-reactivities using different primer sets for sample 3 (Table 2). The top chromatogram was obtained using the DPO primer set. It displays no ambiguity and represents the 16S rRNA gene of Kingella kingae only. The middle chromatogram shows amplification using the CLSI forward/Bosshard reverse primer combination. The area shown is identical to that of the top chromatogram. Coamplification of human DNA gives ambiguity up to bp 121 (red arrow). Thereafter, the 16S rRNA gene of K. kingae continues as a pure sequence. The bottom chromatogram shows amplification using the CLSI primer set. Terminal part of the reverse chromatogram is shown, and the length of the chromatogram is 667 bp (red circle), significantly longer than the expected 16S rRNA amplicon length of 500 bp. The chromatogram represents only human DNA, and the 16S rRNA gene of K. kingae could not be detected.