Table 3

Comparison of sensitivity of the nested multiplex PCR and multiplex PCR methods in real time
Microbe species Order of magnitude [CFU/ml] Detection limit of the multiplex qPCR Order of magnitude [CFU/ml] Detection limit of the nested multiplex qPCR [CFU/ml] *RFU level
105 104 103 102 101 100 [CFU/ml] 105 104 103 102 101 100
+ + + + + + + + 100
A. fumigatus + + 3.7 × 103± 2.4 × 103 + + + + 3.7 × 101± 2.7 × 102
(filamentous fungi) + + 3.2 × 103 CFU/reaction + + + + 1.2 CFU/reaction
+ + **CT (31.2-38.5) + + + + CT (29.1-32.2)
+ + + + + +
+ + + + + + + 50
C. albicans + + + + 9.9 × 102± 3.4 × 103 + + + + + 8.5 × 101± 3.6 × 102
(yeast) + + + + 9.5 × 101 CFU/reaction + + + + + 0.24 CFU/reaction
+ + + CT (33.3-37.2) + + + + + CT (29.7-32.1)
+ + + + + + + +
+ + + + + + + + + 100
S. aureus + + + 4.5 × 103± 2.5 × 103 + + + + + 1.1 × 101± 3.7 × 102
(Gram positive bacteria) + + + 5.1 × 102 CFU/reaction + + + + + 0.78 CFU/reaction
+ + + CT (34.0-36.7) + + + + + CT (25.2-28.0)
+ + + + + + +
+ + + + + + + + 30
E. coli + + + 5.4 × 103± 2.5 × 102 + + + + + 1.3 × 101± 3.7 × 102
(Gram negative bacteria) + + + 6.1 × 102 CFU/reaction + + + + + 0.73 CFU/reaction
+ + + CT (30.5-33.2) + + + + + CT (24.4-27.2)
+ + + + + + + +

“+”- the number of positive amplification results conducted in the five repetitions; “∅” – lack of amplification signal.

*RFU (relative fluorescence unit) signifies the value of the designated baseline.

**CT value, i.e. the consecutive reaction cycle number in which the linear increase of the product cut the established baseline RFU level.

Gosiewski et al.

Gosiewski et al. BMC Microbiology 2014 14:144   doi:10.1186/1471-2180-14-144

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