Microbial Ecology

, Volume 38, Issue 4, pp 358–364 | Cite as

Microbial Responses to Environmentally Toxic Cadmium

  • T.M.  Roane
  • I.L.  Pepper


We analyzed the soil microbial communities from one uncontaminated and two metal-impacted soils and found that while cadmium adversely affected the numbers of culturable bacteria in all soils, cadmium-resistant isolates were found from each of the soils. With exposure to 24 and 48 μg ml-1 soluble cadmium, the metal-contaminated soil communities were more resistant than the uncontaminated soil community. In addition, in one metal-stressed soil, the resistant population became more resistant with increased cadmium levels. Ribosomal 16S DNA sequencing identified the isolates as Arthrobacter,Bacillus, or Pseudomonas spp. Further characterization demonstrated that two of the isolates were highly resistant to soluble cadmium with maximum resistance at 275 μg ml-1 cadmium. These isolates were also resistant to a variety of antibiotics, namely ampicillin, gentamicin, penicillin, and streptomycin, but no overall correlation was found between enhanced antibiotic resistance and cadmium resistance. One Pseudomonas isolate H1 did become more resistant with increasing cadmium levels, suggesting a different resistance mechanism at high cadmium concentrations.


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Copyright information

© 2000 Springer-Verlag New York Inc.

Authors and Affiliations

  • T.M.  Roane
    • 1
  • I.L.  Pepper
    • 2
  1. 1.Department of Biology, University of Colorado, Campus Box 171, Post Office Box 173364, Denver, CO 80217-3364, USAUS
  2. 2.Department of Soil, Water, and Environmental Science, The University of Arizona, 429 Shantz Building #38, Tucson, AZ 85721, USAUS

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