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Table 3 Interference of oxide nanoparticles on bacterial quantification

From: A comparison of conventional methods for the quantification of bacterial cells after exposure to metal oxide nanoparticles

Nanoparticles (mg/ml) ZnO TiO2 SiO2
S. entericaNewport (cells/ml)a S. entericaNewport (cells/ml) S. entericaNewport (cells/ml)
FMC CFU OD660 b FMC CFU OD660 FMC CFU OD660
Total Live    Total Live    Total Live   
0 1.37 × 109 1.36 × 109 8.17 × 108 1.37 × 109 1.23 × 109 1.22 × 109 1.18 × 109 1.23 × 109 1.28 × 109 1.26 × 109 6.32 × 108 1.28 × 109
0.1 1.31 × 109 1.30 × 109 1.00 × 109 1.46 × 109 1.00 × 109 9.94 × 108 7.00 × 108 9.16 × 108 1.23 × 109 1.22 × 109 6.50 × 108 1.20 × 109
0.2 1.29 × 109 1.28 × 109 5.83 × 108 1.28 × 109 8.15 × 108 8.05 × 108 5.67 × 108 5.89 × 108 1.22 × 109 1.20 × 109 5.83 × 108 1.18 × 109
0.3 1.27 × 109 1.14 × 109 7.00 × 108 1.19 × 109 7.14 × 108 7.06 × 108 5.50 × 108 3.23 × 108 1.20 × 109 1.18 × 109 5.83 × 108 1.16 × 109
0.5 1.23 × 109 1.21 × 109 6.33 × 108 1.01 × 109 4.26 × 108 4.13 × 108 4.33 × 108 -c 1.24 × 109 1.21 × 109 5.67 × 108 1.15 × 109
1 1.12 × 109 1.10 × 109 5.00 × 108 7.15 × 108 2.41 × 108 2.35 × 108 1.50 × 108 - 1.22 × 109 1.20 × 109 7.17 × 108 1.09 × 109
  S. epidermidis ATCC 12228 (cells/ml) S. epidermidis ATCC 12228 (cells/ml) S. epidermidis ATCC 12228 (cells/ml)
0 3.53 × 108 3.46 × 108 9.33 × 107 3.53 × 108 4.46 × 108 4.40 × 108 1.20 × 108 4.46 × 108 5.20 × 108 4.74 × 108 2.00 × 108 5.20 × 108
0.1 2.13 × 108 1.94 × 108 2.18 × 107 2.73 × 108 1.21 × 108 1.19 × 108 2.00 × 107 - 1.06 × 108 9.57 × 107 1.18 × 108 4.48 × 108
0.2 1.37 × 108 1.18 × 108 1.63 × 107 1.23 × 108 2.65 × 107 2.62 × 107 2.00 × 107 - 7.27 × 107 6.55 × 107 6.50 × 107 4.54 × 108
0.3 1.71 × 107 1.45 × 107 1.37 × 107 3.20 × 108 1.46 × 107 1.44 × 107 3.33 × 107 - 5.13 × 107 4.60 × 107 5.00 × 107 5.00 × 108
0.5 1.65 × 107 1.45 × 107 1.33 × 107 1.85 × 108 6.47 × 106 6.40 × 106 5.83 × 107 - 6.72 × 107 6.32 × 107 5.83 × 107 4.75 × 108
1 3.31 × 107 3.00 × 107 1.10 × 107 - 6.20 × 107 6.11 × 107 1.07 × 108 - 2.21 × 108 2.04 × 108 1.18 × 108 4.84 × 108
  E. faecalis ATCC 27274 (cells/ml) E. faecalis ATCC 27274 (cells/ml) E. faecalis ATCC 27274 (cells/ml)
0 2.29 × 109 2.28 × 109 1.17 × 109 2.29 × 109 2.21 × 109 2.17 × 109 1.07 × 109 2.21 × 109 2.47 × 109 2.42 × 109 1.87 × 109 2.47 × 109
0.1 2.14 × 109 2.06 × 109 1.50 × 109 2.13 × 109 1.84 × 109 1.81 × 109 9.50 × 108 1.69 × 109 2.17 × 109 2.11 × 109 1.22 × 109 2.40 × 109
0.2 2.0 × 109 1.92 × 109 1.42 × 109 1.73 × 109 1.42 × 109 1.40 × 109 5.50 × 108 1.07 × 109 1.64 × 109 1.61 × 109 1.18 × 109 2.30 × 109
0.3 1.47 × 109 1.44 × 109 1.28 × 109 1.54 × 109 1.23 × 109 1.22 × 109 3.80 × 108 5.26 × 108 1.34 × 109 1.33 × 109 1.14 × 109 2.23 × 109
0.5 1.45 × 109 1.40 × 109 1.15 × 109 8.57 × 108 5.58 × 108 5.54 × 108 1.30 × 108 - 8.69 × 108 8.59 × 108 7.00 × 108 2.10 × 109
1 1.07 × 109 1.03 × 109 7.00 × 108 - 1.70 × 106 1.60 × 106 2.95 × 106 - 4.44 × 108 4.33 × 108 5.00 × 108 1.90 × 109
  E. coli ATCC 25922 (cells/ml) E. coli ATCC 25922 (cells/ml) E. coli ATCC 25922 (cells/ml)
0 6.56 × 108 5.64 × 108 3.98 × 108 6.65 × 108 6.41 × 108 6.32 × 108 6.83 × 108 6.41 × 108 5.52 × 108 5.46 × 108 5.67 × 108 5.52 × 108
0.1 5.22 × 108 4.95 × 108 3.93 × 108 6.18 × 108 3.28 × 108 3.26 × 108 8.33 × 107 4.86 × 108 3.73 × 108 3.68 × 108 2.83 × 108 5.21 × 108
0.2 4.50 × 108 4.17 × 108 3.88 × 108 5.56 × 108 7.67 × 107 7.61 × 107 1.17 × 107 3.07 × 108 2.52 × 108 2.49 × 108 2.17 × 108 5.08 × 108
0.3 3.65 × 108 3.54 × 108 3.87 × 108 4.97 × 108 1.90 × 107 1.88 × 107 1.17 × 107 1.63 × 108 2.19 × 108 2.16 × 108 1.50 × 108 5.11 × 108
0.5 1.36 × 108 1.17 × 108 2.93 × 108 2.89 × 108 7.13 × 106 6.97 × 106 9.02 × 106 - 2.03 × 108 2.02 × 108 2.50 × 108 4.76 × 108
1 1.43 × 108 1.37 × 108 3.10 × 108 1.59 × 108 2.21 × 107 2.18 × 107 4.58 × 107 - 2.38 × 108 2.37 × 108 2.83 × 108 4.67 × 108
  1. aBacterial cell concentrations were measured by flow cytometry (FCM), culture-based counting for colony-forming units (CFU), and spectrophotometer method of optical density (OD) measurement after 1 hr exposure to different concentrations of ZnO, TiO2 and SiO2 nanoparticles; inoculum used for each experiment was indicated in the control samples, i.e. no nanoparticles.
  2. bPresented data were converted from each sample cell concentration according to the each species standard curve of cell/ml vs OD660 and as mean of triplicate with standard deviations (SD) of < 5% from FCM and OD600 and <10% from CFU. Inoculum used for each experiment was indicated in the control samples, i.e. no nanoparticles.
  3. cValue was negative.