Carl-Fredrik Flach1, Anna Johnning2, Ida Nilsson1, Kornelia Smalla3, Erik Kristiansson4, D G Joakim Larsson5. 1. Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. 2. Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden. 3. Julius Kühn-Institut-Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany. 4. Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden. 5. Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden joakim.larsson@fysiologi.gu.se.
Abstract
OBJECTIVES: Antibiotic-polluted environments may function as reservoirs for novel resistance plasmids not yet encountered in pathogens. The aims of this study were to assess the potential of resistance transfer between bacteria from such environments and Escherichia coli, and to characterize the conjugative elements involved. METHODS: Sediment samples from Kazipally lake and Asanikunta tank, two Indian lakes with a history of severe pollution with fluoroquinolones, were investigated. Proportions of resistant bacteria were determined by selective cultivation, while horizontal gene transfer was studied using a GFP-tagged E. coli as recipient. Retrieved transconjugants were tested for susceptibility by Etest(®) and captured conjugative resistance elements were characterized by WGS. RESULTS: The polluted lakes harboured considerably higher proportions of ciprofloxacin-resistant and sulfamethoxazole-resistant bacteria than did other Indian and Swedish lakes included for comparison (52% versus 2% and 60% versus 7%, respectively). Resistance plasmids were captured from Kazipally lake, but not from any of the other lakes; in the case of Asanikunta tank because of high sediment toxicity. Eight unique IncA/C and IncN resistance plasmids were identified among 11 sequenced transconjugants. Five plasmids were fully assembled, and four of these carried the quinolone resistance gene qnrVC1, which has previously only been found on chromosomes. Acquired resistance genes, in the majority of cases associated with class 1 integrons, could be linked to decreased susceptibility to several different classes of antibiotics. CONCLUSIONS: Our study shows that environments heavily polluted with antibiotics contain novel multiresistance plasmids transferrable to E. coli.
OBJECTIVES: Antibiotic-polluted environments may function as reservoirs for novel resistance plasmids not yet encountered in pathogens. The aims of this study were to assess the potential of resistance transfer between bacteria from such environments and Escherichia coli, and to characterize the conjugative elements involved. METHODS: Sediment samples from Kazipally lake and Asanikunta tank, two Indian lakes with a history of severe pollution with fluoroquinolones, were investigated. Proportions of resistant bacteria were determined by selective cultivation, while horizontal gene transfer was studied using a GFP-tagged E. coli as recipient. Retrieved transconjugants were tested for susceptibility by Etest(®) and captured conjugative resistance elements were characterized by WGS. RESULTS: The polluted lakes harboured considerably higher proportions of ciprofloxacin-resistant and sulfamethoxazole-resistant bacteria than did other Indian and Swedish lakes included for comparison (52% versus 2% and 60% versus 7%, respectively). Resistance plasmids were captured from Kazipally lake, but not from any of the other lakes; in the case of Asanikunta tank because of high sediment toxicity. Eight unique IncA/C and IncN resistance plasmids were identified among 11 sequenced transconjugants. Five plasmids were fully assembled, and four of these carried the quinolone resistance gene qnrVC1, which has previously only been found on chromosomes. Acquired resistance genes, in the majority of cases associated with class 1 integrons, could be linked to decreased susceptibility to several different classes of antibiotics. CONCLUSIONS: Our study shows that environments heavily polluted with antibiotics contain novel multiresistance plasmids transferrable to E. coli.
Authors: Anna Johnning; Erik Kristiansson; Jerker Fick; Birgitta Weijdegård; D G Joakim Larsson Journal: Front Microbiol Date: 2015-12-09 Impact factor: 5.640
Authors: Fredrik Boulund; Fanny Berglund; Carl-Fredrik Flach; Johan Bengtsson-Palme; Nachiket P Marathe; D G Joakim Larsson; Erik Kristiansson Journal: BMC Genomics Date: 2017-09-02 Impact factor: 3.969