Bacteria with dual resistance to elevated concentrations of heavy metals and antibiotics in Nigerian contaminated systems

Abstract

Samples of soil, water, and sediments from industrial estates in Lagos were collected and analyzed for heavy metals and physicochemical composition. Bacteria that are resistant to elevated concentrations of metals (Cd(2+), Co(2+), Ni(2+), Cr(6+), and Hg(2+)) were isolated from the samples, and they were further screened for antibiotic sensitivity. The minimum tolerance concentrations (MTCs) of the isolates with dual resistance to the metals were determined. The physicochemistry of all the samples indicated were heavily polluted. Twenty-two of the 270 bacterial strains isolated showed dual resistances to antibiotics and heavy metals. The MTCs of isolates to the metals were 14 mM for Cd(2+), 15 mM for Co(2+) and Ni(2+), 17 mM for Cr(6+), and 10 mM for Hg(2+). Five strains (Pseudomonas aeruginosa, Actinomyces turicensis, Acinetobacter junni, Nocardia sp., and Micrococcus sp.) resisted all the 18 antibiotics tested. Whereas Rhodococcus sp. and Micrococcus sp. resisted 15 mM Ni(2+), P. aeruginosa resisted 10 mM Co(2+). To our knowledge, there has not been any report of bacterial strains resisting such high doses of metals coupled with wide range of antibiotics. Therefore, dual expressions of antibiotics and heavy-metal resistance make the isolates, potential seeds for decommissioning of sites polluted with industrial effluents rich in heavy metals, since the bacteria will be able to withstand in situ antibiosis that may prevail in such ecosystems.

Analysis of Bifenthrin Degrading Bacteria from Rhizosphere of Plants Growing at Tannery Solid Waste

“…These results are Conc. (µl•ml −1 ) 100 300 100 300 100 300 100 300 100 300 100 300 100 300 in close agreement with findings of [25]. These metals are present in industrial effluents as in case of tannery solid waste.…”

“…Xanthomonas maltophilia and Saprobic coryneform were studied by [10] from rhizosphere of wheat and barley. Previous work has revealed that potential bifenthrin degrading microorganisms were mostly Bacillus, Pseudomonas, Serratia, yeast and Fusarium [16] [21]- [25]. Present study revealed that both strains exhibited resistance to heavy metals were also resistant to antibiotics.…”

Identification of Enterococcus faecalis bacteria resistant to heavy metals and antibiotics in surface waters of the Mololoa River in Tepic, Nayarit, Mexico

“…Intriguingly, Hg was the only HM to which all isolates were resistant. HM have been previously reported to potentially influence the selection process of antibioticresistant strains by affecting the means of survival, and if another resistance is present, shared mechanisms for both types of resistance are developed (Akinbowale et al 2007;Alonso et al 2000Alonso et al , 2001Baker-Austin et al 2006;Oyetibo et al 2009;Russell 2000). This process can lead to the dissemination of strains that are resistant to a vast number of antibiotics having a direct impact in human health, reducing the options for treatment and raising costs.…”

Metal biouptake by actively growing cells of metal-tolerant bacterial strains

“…The isolation characterization and identification of the bacterial strains used in this study has been reported elsewhere (Oyetibo et al 2010). The bacterial strains w e r e P s e u d o m o n a s a e r u g i n o s a C A 2 0 7 N i , Burkholderia cepacia AL96Co, Corynebacterium kutscheri FL108Hg, and Rhodococcus sp.…”

“…Discharges of industrial wastewater into surrounding hydrosphere have been reportedly responsible for elevated concentrations of toxic metals in the receiving ecosystem (Oyetibo et al 2010;Oyeyiola et al 2006). HMs, as a notable environmental stressor, arouse or exacerbate environmental diseases, which often manifest as cancer, chronic lung disease, diabetes, and neuro-degeneration (Franco et al 2009;Hansen et al 2006;Valko et al 2005).…”