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Table 7 Summary of test results of source water (unfiltered)

From: Diarrhea prevalence in a randomized, controlled prospective trial of point-of-use water filters in homes and schools in the Dominican Republic

Type of water sample testing

Bacterial genus/heavy metal

Percent of samples present at filter install

Percent of samples present at follow-up

p value comparing install to follow-upb

p value for linear trendc

p value for seasonal effectd

Bacteria detected

Acinetobacter

53.8% (14/26)

35.3% (6/17)

0.25

0.39

0.56

Aeromonas

16.1% (5/31)

20% (4/20)

0.72

0.51

0.64

Burkholderia

6.45% (2/31)

5% (1/20)

0.83

0.31

0.54

Campylobacter

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Enterobacter

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Escherichia/ Shigella

45.5% (10/22)

50% (6/12)

0.80

0.90

0.90

Francisella

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Helicobacter

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Klebsiella

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Legionella

58.1% (18/31)

70% (14/20)

0.18

0.06

0.41

Leptospira

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Mycobacterium

30% (9/30)

57.9% (11/19)

0.06

0.19

0.08

Pseudomonas

85.2% (23/27)

94.4% (17/18)

0.35

0.62

0.40

Salmonella

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Staphylococcus

12.9% (4/31)

15.8% (3/19)

0.78

0.79

0.87

Tsukamurella

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Vibrio

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Yersinia

3.23% (1/31)

0% (0/20)

0.98

0.69

0.47

Dissolved heavy metal ions detected

Arsenic

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Barium

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Cadmium

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Chromium

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Coppera

64.7% (22/34)

68.2% (15/22)

0.79

0.38

0.34

Leada

8.82% (3/34)

4.55% (1/22)

0.55

0.38

0.63

Nickel

0% (0/34)

0% (0/22)

1.00

1.00

1.00

Seleniuma

5.88% (2/34)

0% (0/22)

0.96

0.16

0.21

  1. a Detected levels were below WHO action guidelines in all samples
  2. b From Fisher’s exact test comparing baseline to follow-up prevalence
  3. c From test of linear trend over course of study
  4. d From test of seasonal differences over course of study