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Table 2 Amount/concentration. changes (log-levels/%) and p values (<0.05: significant) of CFU of different bacterial strains on Ti samples with high and low concentrated Ag-DLC

From: Antibacterial efficacy of titanium-containing alloy with silver-nanoparticles enriched diamond-like carbon coatings

High concentrated Ag-DLC-Ti

Ti (untreated)

DLC-Ti

Ag-DLC-Ti (Ag:PVP 1:2)

S. epidermidis

 Surface adhesion

 CFU ± SD

2.1 × 105 ± 7.6 × 104

3.3 × 105 ± 2.4 × 105

8.1 × 100 ± 1.9 × 101

 Changes compared to Ti (log-levels/%)a,b

 

+0.2/+57 %

−4.4/−99.9 %

 p values

0.149

<0.05

 Growth in surrounding medium

 CFU/ml ± SD

4.5 × 105 ± 2.8 × 105

1.0 × 106 ± 4.0 × 105

3.4 × 102 ± 1.1 × 103

 Changes compared to Ti (log-levels/%)a,b

 

+0.3/+122.2 %

−2.8/−99.9 %

 p values

<0.05

<0.05

S. aureus

 Surface adhesion

 CFU ± SD

7.3 × 106 ± 3.1 × 106

7.8 × 106 ± 2.4 × 106

1.7 × 104 ± 3.1 × 104

 Changes compared to Ti (log-levels/%)a,b

 

+0.03/+6.8 %

−2.6/−99.9 %

 p values

0.428

<0.05

 Growth in surrounding medium

 CFU/ml ± SD

1.1 × 108 ± 4.1 × 107

8.4 × 107 ± 6.1 × 107

3.6 × 105 ± 5.4 × 105

 Changes compared to Ti (log-levels/%)a,b

 

−0.1/−23.6 %

−2.5/−95.9 %

 p values

0.213

<0.05

P. aeruginosa

 Surface adhesion

 CFU ± SD

1.6 × 106 ± 7.7 × 105

1.3 × 106 ± 5.7 × 105

3.8 × 100 ± 1.5 × 101

 Changes compared to Ti (log-levels/%)a,b

 

−0.09/−18.6 %

−5.6/−99.9 %

 p values

0.533

<0.05

 Growth in surrounding medium

 CFU/ml ± SD

2.4 × 108 ± 3.8 × 107

2.1 × 108 ± 2.7 × 107

7.4 × 102 ± 1.6 × 103

 Changes compared to Ti (log-levels/%)a,b

 

−0.06/−12.5 %

−5.5/−99.9 %

 p values

0.161

<0.05

Low concentrated Ag-DLC-Ti

Ti (untreated)

DLC-Ti

Ag-DLC-Ti

Ag:PVP 1:10

Ag:PVP 1:20

S. aureus

 Surface adhesion

 CFU ± SD

6.8 × 105 ± 7.6 × 104

9.7 × 105 ± 2.4 × 104

5.9 × 103 ± 4.9 × 103

1.3 × 104 ± 5.2 × 103

 Changes compared to Ti (log-levels/%)a,b

 

+0.2/+57 %

−1.1/−91.8 %

−0.7/−81.9 %

 p values

0.149

<0.05

<0.05

 Growth in surrounding medium

 CFU/ml ± SD

3.1 × 105 ± 1.8 × 105

5.5 × 105 ± 2.0 × 105

5.2 × 104 ± 3.8 × 104

1.4 × 105 ± 5.4 × 104

 Changes compared to Ti (log-levels/%)a,b

 

+0.3/+122.2 %

−0.8/−98.3 %

−0.3/−54.8 %

 p values

<0.05

<0.05

<0.05

  1. CFU colony forming units, SD standard deviation
  2. alog-levels = bacterial counts calculated as shown in following equation: log-levels = log10(CFU of Ag-DLC-Ti) − log10(CFU of untreated Ti)
  3. bPositive values (log-levels/%) express increased bacterial growth on DLC-Ti/Ag-DLC-Ti compared to untreated Ti, negative values express reduced bacterial growth on DLC-Ti/Ag-DLC-Ti compared to untreated Ti