Potential risks of antibiotic resistant bacteria and genes in bioremediation of petroleum hydrocarbon contaminated soils

• Published in: Environmental science--processes & impacts Vol. 22; no. 5; pp. 111 - 1124
• Main Authors: Cunningham, Colin J, Kuyukina, Maria S, Ivshina, Irena B, Konev, Alexandr I, Peshkur, Tatyana A, Knapp, Charles W
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01.05.2020
• Subjects: Agrochemicals; Animal manures; Antibiotic resistance; Antibiotics; Bacteria; Bioremediation; Contaminated land; Drug resistance; Fertilizers; Gene transfer; Genes; Health risks; Horizontal transfer; Hydrocarbons; Land pollution; Metals; Microorganisms; Nutrients; Organic wastes; Petroleum; Petroleum hydrocarbons; Pollutants; Pretreatment; Residues; Sediment pollution; Sewage sludge; Soil bacteria; Soil contamination; Soil investigations; Soil microorganisms; Soil pollution; Soil remediation; Soils; Sustainability; Waste treatment
• ISSN: 2050-7887; 2050-7895
• DOI: 10.1039/c9em00606k

Bioremediation represents a sustainable approach to remediating petroleum hydrocarbon contaminated soils. One aspect of sustainability includes the sourcing of nutrients used to stimulate hydrocarbon-degrading microbial populations. Organic nutrients such as animal manure and sewage sludge may be perceived as more sustainable than conventional inorganic fertilizers. However, organic nutrients often contain antibiotic residues and resistant bacteria (along with resistance genes and mobile genetic elements). This is further exacerbated since antibiotic resistant bacteria may become more abundant in contaminated soils due to co-selection pressures from pollutants such as metals and hydrocarbons. We review the issues surrounding bioremediation of petroleum-hydrocarbon contaminated soils, as an example, and consider the potential human-health risks from antibiotic resistant bacteria. While awareness is coming to light, the relationship between contaminated land and antibiotic resistance remains largely under-explored. The risk of horizontal gene transfer between soil microorganisms, commensal bacteria and/or human pathogens needs to be further elucidated, and the environmental triggers for gene transfer need to be better understood. Findings of antibiotic resistance from animal manures are emerging, but even fewer bioremediation studies using sewage sludge have made any reference to antibiotic resistance. Resistance mechanisms, including those to antibiotics, have been considered by some authors to be a positive trait associated with resilience in strains intended for bioremediation. Nevertheless, recognition of the potential risks associated with antibiotic resistant bacteria and genes in contaminated soils appears to be increasing and requires further investigation. Careful selection of bacterial candidates for bioremediation possessing minimal antibiotic resistance as well as pre-treatment of organic wastes to reduce selective pressures ( e.g. , antibiotic residues) are suggested to prevent environmental contamination with antibiotic-resistant bacteria and genes. The problems associated with potential risks of antibiotic resistance spreading during bioremediation of oil-contaminated soil are discussed. Careful selection of bacterial strains and pretreatment of organic wastes used as fertilizers are suggested.