Copper tolerance and antibiotic resistance in soil bacteria from olive tree agricultural fields routinely treated with copper compounds

Abstract

BACKGROUND Heavy metal pollution may act as persistent selective pressure that favors the spread of antimicrobial resistance in natural environments. The aim of this study was to isolate and identify metal‐tolerant bacteria from soils in olive tree fields routinely treated with copper‐derived compounds and to evaluate the tolerance of bacterial strains to other metals and their resistance to clinically relevant antibiotics. RESULTS Five hundred and ninety‐five bacterial isolates from 45 olive tree agricultural fields were studied. Minimum inhibitory concentrations (MICs) ≥ 16 mmol L−1 were detected for copper (57% of isolates), zinc (37%) and lead (62%), while only 3% had MICs ≥ 12 mmol L−1 for nickel. Ninety‐six metal‐tolerant strains were selected for identification and antibiotic resistance determination. Most isolates belonged to the genera Pseudomonas (37%), Bacillus (23%) and Chryseobacterium (20%), while 6% were identified as Variovorax, 4% as Stenotrophomonas and 2% as Serratia or Burkholderia. Highest copper tolerance was detected among Pseudomonas. Over 75% of the strains with high copper tolerance were also resistant to vancomycin, 50% to ampicillin and 40% to erythromycin or trimethoprim/sulfamethoxazole. CONCLUSION Bacteria from olive soils are tolerant to metals, mainly copper, but also zinc and lead, as well as resistant to clinically important antibiotics, which could be a troublesome issue in clinical settings. © 2019 Society of Chemical Industry

Trace metals and animal health: Interplay of the gut microbiota with iron, manganese, zinc, and copper

“…High levels of copper exposure may induce toxicity and the development of copper resistance in various pathogenic bacteria ( Altimira et al., 2012 ; Agga et al., 2014 ; Zhang et al., 2019b , 2019c ). Extensive use of copper in industry and mining and the widespread use of pesticides in agricultural production are major sources of copper pollution of soils and water ( Altimira et al., 2012 ; Glibota et al., 2019 ). Thus, the precise and tight regulation of copper levels in the body is required to prevent unwanted detrimental effects or dysbiosis in the host.…”

Microbiological safety and antibiotic resistance risks at a sustainable farm under large-scale open-air composting and composting toilet systems

“…Pseudomonas and Variovorax are common indigenous flora in soil and water, both of which are associated with a variety of rare metabolic characteristics, including degradation of toxic and complex compounds [58]. Among them, Variovorax can complete a variety of catabolic pathways, has other characteristics related to the mediation of metal ions, organic sulphides, and other compounds [58], and exhibits resistance to multiple antibiotics [58,59]. Numerous studies have confirmed the contribution of compost application to vegetable microorganisms, especially to multi-resistant strains [28].…”

Genetic Determinants for Metal Tolerance and Antimicrobial Resistance Detected in Bacteria Isolated from Soils of Olive Tree Farms

“…Heavy metal tolerant bacteria were isolated from soil samples of olive tree farms in a previous study [21]. Strain identification and antibiotic resistance phenotype were established [21] and the 96 strains used in the present study were selected according to soil source and metal tolerance [21].…”

“…Application of copper-derived compounds in olive tree farms is a common practice in South Spain for prevention or treatment of infections caused by the fungus Spilocaea oleagina. Phenotypic metal tolerance and AR in bacteria from Cu-contaminated soils in olive tree farms was established in a previous study [21]. The purpose of this study was to evaluate the presence of genetic determinants for metal tolerance or AR in strains isolated from Cu-treated soils in the province of Jaén and classified as resistant to both type of compounds.…”