Table 2

Susceptibility of Escherichia coli JM109 to metal cations with 2 or 24 h of exposure in rich (LB + B1) medium

Periodic group

Metal ion

Exposure time (h)

MIC (mM)

MBC (mM)

MBEC (mM)

Fold Tolerance1


7B

Mn2+

2

37 ± 0

> 149

> 149

na

24

198 ± 86

223 ± 86

1.1

8B

Ni2+

2

7.5 ± 2.1

> 140

>140

na

24

17 ± 0

29 ± 11

1.7

1B

Cu2+

2

4.5 ± 1.4

16 ± 0

16 ± 0

1.0

24

16 ± 0

16 ± 0

1.0

Ag+

2

0.06 ± 0.02

0.06 ± 0.02

1.6 ± 0.7

24

24

0.06 ± 0.02

0.04 ± 0

0.7

2B

Zn2+

2

4.2 ± 2.4

125 ± 0

> 125

≥ 2.0

24

31 ± 0

31 ± 0

1.0

Cd2+

2

1.1 ± 0.2

55 ± 21

73 ± 0

1.3

24

2.3 ± 0

3.0 ± 1.3

1.3

Hg2+

2

0.04 ± 0.02

0.14 ± 0.04

0.32 ± 0.22

2.3

24

0.04 ± 0

0.04 ± 0

1.0

3A

Al3+

2

nd

> 304

> 304

na

24

19 ± 0

19 ± 0

1.0

4A

Sn2+

2

nd

> 17

> 17

na

24

17 ± 0

17 ± 0

1.0


A portion of the data in this table (at the 24 h timepoint) represents a greater number of trials and reanalysis of the data originally reported in an earlier study [10].

na indicates a calculation that is not applicable

nd indicates an MIC that could not be determined due to metal precipitation

bold indicates the fold tolerance at 24 h of exposure

1the fold tolerance, given the sensitivity of the assay on a log2 scale, is equal to the ratio of the means of MBEC:MBC100

Harrison et al. BMC Microbiology 2005 5:53   doi:10.1186/1471-2180-5-53

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