Figure 1
TAC optimization. (A) 50% Tween-20/Triton X-100 and 0.1% saponin treatment on the yield of pathogen cells from whole blood specimens. 103 CFU S. aureus was mixed in 1 mL blood from healthy donors and then lysed by Tween-20/Triton X-100 or saponin. The colony numbers were determined by a plate count. (B,C). TNA extraction kit performance on blood culture specimens (B) and mock whole blood specimens (C). Kit 1 is the BiOstic bacteremia DNA isolation kit; Kit 2 is the QIAamp DNA Blood Mini Kit; Kit 3 is the QIAamp UCP Pathogen Mini Kit; Kit 4 is the TIANamp Blood DNA Kit; Kit 5 is the QIAamp cador Pathogen Mini Kit. M represents the benzyl alcohol-guanidine hydrochloride method. For blood culture specimens, three blood culture samples positive for S. aureus (G+), E. coli (G−), or C. albicans (fungi) were used. For whole blood specimens, three whole blood mock specimens spiked with 101 CFU/mL of S. aureus, E. coli, and C. albicans were used. (D) The effect of TNA combined with reverse transcription on amplifying efficiency. 101 and 102 CFU S. aureus (G+), E. coli (G−), or C. albicans (fungi) were used to make mock specimens. The cycle threshold (Ct) was compared with RT or without RT. (E) The effect of 0.1% blue dextran 2000 on the TAC assay. 106 CFU S. aureus (G+), 107 CFU P. aeruginosa (G−) and 104 CFU C. albicans (fungi) were used to make mock specimens. B+, TAC assay with blue dextran 2000; B−, TAC assay without blue dextran 2000.
