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					Source: http://www.doksinet  The environmental resistome  Dr Fiona Walsh   Source: http://www.doksinet  Where does AR originate? Recent years  Billions of years ago  Bacteria emerge from premordial soup  Bacteria live in the environment together producing and resisting antibiotics, bioactive compounds and toxins  Antibiotics in medicine  Antibiotic resistance research  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Concepts to date relating to environment Soil = Reservoir of antibiotic resistance  Manure increases the abundance and diversity of resistance genes  Faecal pollution of water causes antibiotic resistance pollution of water (Joseph Kelly image of Lough Mask  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Antibiotic resistance research Knowledge  Soil 1400 papers  Water 3700 papers  Wild animal 1400 papers Food 8000 papers  An approximate overview of the number of papers published  Animal 24000 papers  Human 105000 papers  Dr Fiona
Walsh/Biology Department   Source: http://www.doksinet  Antibiotic resistance research Antibiotic resistance in pathogens Treatment options  Antibiotic resistance outside pathogens Large proportion bacteria do not grow  Molecular biology tools especially next generation sequencing enabled the analysis of total populations   Source: http://www.doksinet  Tools for investigating resistance in the environment Whole genome sequencing  qPCR PCR  Proteomics RT: 0.97 - 13001 46.68  100 95  71.75  NL: 3.83E9 Base Peak MS N2 2  78.09  74.81  90  Culture  78.22  85  105.07  80  Amplicon sequencing  75 50.13  39.46  65  Relative Abundance  105.33  36.90  70  100.02  60  43.53  55  53.32  59.33 95.77  50 36.02  129.39  45  53.74  59.66  40  63.61 55.02  35  70.02  113.91  79.61  88.98  30  113.78 112.72  91.32 67.42  25  83.17  107.59  33.14 20  129.12  32.80  84.88  15 32.57 10  29.50 27.89 22.03 2684 15.77 1800  5 0  1.90 742 10  20  30  124.41 114.50 117.46  40  50  60  70  80  90  100  110  120
 130  Time (min)  Functional metagenomics  Metagenomics  IMGM Laboratories Epicentre   Source: http://www.doksinet  Soil Source of Antibiotic Resistance Antibiotics sources: Soil microorganisms  Antibiotics resistance sources: Soil microorganisms? Erythrobacter litoralis  blaNDM  Kluyvera species  blaCTX‐M  Clinically identified resistance genes  Zheng et al., 2011, Oliver et al, 2001  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Identifying antibiotic resistance in the environment: Culture Soil Suspension (125 g/5 ml)  Growing resistant bacteria 10 different soils (Switzerland) Deep‐well culture plates 20 mg/L antibiotic in LB 7 days  Plated onto antibiotic media  Mountains, urban, farms, orchard, lakeside  All representative types tested for MDR against all 23 antibiotics  Dr Fiona Walsh/Biology Department   Rifampicin  Colistin  Erythromycin  Sulfisoxazole  Sulfamethoxazole  Tetracycline  Trimethoprim  Novobiocin  D‐cycloserine  Chloramphenicol  Naladixic
Acid  Ciprofloxacin  Levofloxacin  Sisomicin  Gentamicin  Kanamycin  Streptomycin  Amikacin  Vancomycin  Cfx+Clavulanic acid  Cephalexin  Cefotaxime  Dicloxacillin  Penicillin  % Resistance  Source: http://www.doksinet  Selected Resistome and % Mediated by Efflux 100  90  80  70  60  50  40  30  20  10  0  Antibiotics coloured by class  Fiona Walsh/Dept of Biology   Source: http://www.doksinet  Soil contains resistant bacteria But are the resistance mechanisms the same as in human pathogens? Mobile resistance genes: • Extended spectrum beta‐lactamases blaTEM, blaSHV, blaOXA, blaCTX‐M Groups 1, 2, 8, 9 and 25, blaVEB, blaPER, blaGES, blaNDM  • Plasmid mediated quinolone resistance genes aac(6’)Ib‐cr, qnrA, qnrB, qnrS, qep  None present  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Relevance of novel environmental resistances Will these resistance mechanisms ever transfer to human pathogens? Mobility – plasmids transfer AR genes between bacteria
Stability – can they survive under stressful conditions? • Do they maintain the resistance phenotype in pathogens? • Will they ever emerge from the soil to cause clinical problems? blaNDM, blaCTX‐M, blaSHV, qnr.   Source: http://www.doksinet  Environment as sink of antibiotic resistance How do our activities influence antibiotic resistance in the environment?  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Human waste Human bacteria  www.waterworldcom  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  WWTP effluent across EU Studying the effluents as sources of antibiotics, AR genes and bacteria Detected across EU Resistant bacteria Mobile resistance genes Antibiotics at varying concentrations WWTP effluents are sources of antibiotics, AR genes and bacteria – no regulations   Source: http://www.doksinet  Total and amoxicillin, tetracycline and ciprofloxacin non‐susceptible/resistant coliforms Mean log mFC faecal coliforms ‐4.00  ‐2.00 
0.00  2.00  4.00  Mean log mFC + AML faecal coliforms 6.00  ‐2.00  IE2  IE2  IE2  IE2 IE1 IE1 NO1  IE1 IE1 NO1 NO1  0.00  2.00  4.00  NO1 ES1 ES1 CY2  ES1 ES1 CY2 CY2  CY2 CY1 CY1 DE2 DE2 DE1  CY1 CY1 DE2 DE2 DE1 DE1  DE1 PT2 PT2 PT1 PT1  PT2 PT2 PT1 PT1  mFC  mFC + AML  mFC  6.00  Mean log mFC + TET faecal coliforms ‐2.00  0.00  2.00  4.00  Mean log mFC +CIP faecal coliforms ‐2.00  IE2 IE2 IE1 IE1  IE2 IE2 IE1 IE1  NO1 NO1 ES1 ES1  NO1 NO1 ES1 ES1  CY2 CY2 CY1  CY2 CY2 CY1  CY1 DE2 DE2 DE1  CY1 DE2 DE2 DE1  DE1 PT2 PT2  DE1 PT2 PT2  PT1 PT1  PT1 PT1  mFC + TET  mFC  0.00  2.00  mFC + CIP  4.00  mFC  6.00   Source: http://www.doksinet  Antibiotic concentrations Antibiotics identified across EU partner countries: Antibiotic class  Antibiotic  Cephalosporins  Cefalexin  Trimethoprim  Trimethoprim  Quinolones/Fluoroquinolones  Nalidixic acid, Ciprofloxacin, Ofloxacin (enrofloxacin)  Lincosamides  Clindamycin  Macrolides  Azithromycin, clarithromycin  Nitromidazole  Methronidazole 
Penicillins  Ampicillin  Sulfonamides  Sulfamethoxazole, sulfapyridine  Tetracyclines  Tetracycline   Source: http://www.doksinet  Selected antibiotic resistance genes detected in relatively high abundances (qPCR) Gene  Resistance  blaOXA, cfxA  Beta‐lactams e.g penicillin  Int1  Mobility element  qacA  Quaternary ammonium compounds (disinfectants)  sul1  Sulphonamides  tetQ, tetC  Tetracyclines  aadA, strB  Aminoglycosides – Spectinomycin, Streptomycin  ermF  Macrolides e.g erythromycin   Source: http://www.doksinet  Waste & Water Regulations for water quality: Chemicals (toxic chemicals) Indicator bacteria (coliforms, enterococci) No regulations for WWTP discharge into water or water quality : Antibiotic concentrations Antibiotic resistant bacteria Antibiotic resistance genes  Dr Fiona Walsh/Biology Department   Source: http://www.doksinet  Plasmid mediated resistance • Currently characterising >30 plasmids • Both exogenous extraction from samples directly and from
isolated bacteria • MDR and all resistance phenotypes identified on plasmids   Source: http://www.doksinet  Conclusions • If environment is a major source of novel/known AR mechanisms we need to identify them and their methods of transmission or barriers to their transfer • Then can identify risks to animal/human/environmental health • We need to measure the impact of our activities, climate change and changing environments on the environmental resistome in order to measure changing risks to animal/human/environmental health   Source: http://www.doksinet  Acknowledgements Swiss Federal Department of Agriculture EU Leonardo stiftung EPA through Water JPI project StARE (WATER/JPI/0001/2013) COST Actions: TD0803 DARE, ES1403 NEREUS