Table 2 Comparison of the relative abundance of dfrB gene variants (copies per 16 S rRNA gene copies) in WWTP effluents and river samples.

From: Trimethoprim resistance in surface and wastewater is mediated by contrasting variants of the dfrB gene

Gene variant

Wastewater samples

River samples

Higher in

adj. p value

Signif. code

Confirmed by split sampling in

dfrB1

3.7e−05

1.8e−06

Wastewater

1.9e−17

***

2/2 subsets

dfrB2

3.9e−06

1.2e−06

Wastewater

6.3e−04

***

2/2 subsets

dfrB3

6.6e−05

5.9e−06

Wastewater

1.5e−05

***

2/2 subsets

dfrB4

1.9e−05

4.7e−06

Wastewater

2.4e−07

***

2/2 subsets

dfrB5

1.6e−06

0e+00

Wastewater

0.0064

**

1/2 subsets

dfrB7

4.7e−06

0e+00

Wastewater

8.8e−06

***

2/2 subsets

dfrB9

0e+00

4.6e−05

River samples

3.5e−06

***

2/2 subsets

dfrB10

2.4e−06

2e−04

River samples

1.3e−17

***

2/2 subsets

dfrB13

0e+00

2.2e−05

River samples

0.0011

**

1/2 subsets

dfrB14

3.5e−06

1.7e−05

River samples

0.26

n.s.

 

dfrB15

7.8e−07

2.3e−06

River samples

1

n.s.

 

dfrB16

3.9e−07

1.2e−06

River samples

0.65

n.s.

 

dfrB17

0e+00

1.2e−06

River samples

0.44

n.s.

 

dfrB19

0e+00

3.5e−06

River samples

0.14

n.s.

 

dfrB20

0e+00

5.9e−07

River samples

0.57

n.s.

 

dfrB21

0e+00

5.9e−07

River samples

0.57

n.s.

 
  1. Reported p values refer to a Wilcoxon rank sum test with the null hypothesis being that the relative abundances of dfrB gene variants are equal in both groups. Each variant was considered a distinct hypothesis and p values were adjusted accordingly (***: p < 0.001, **: p < 0.01, n.s.: not significant). The rightmost column indicates whether the significance of contrasts (adj. p value  <  0.05) could be verified on independent data subsets, each representing 50% of the bacterial DNA from wastewater and river samples, respectively.
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