{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T22:30:10Z","timestamp":1787869810594,"version":"build-2784847793"},"reference-count":62,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2021,8,5]],"date-time":"2021-08-05T00:00:00Z","timestamp":1628121600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100008049","name":"Fundaci\u00f3n Banco Santander","doi-asserted-by":"publisher","award":["FUSP-BS-PPC01\/2014"],"award-info":[{"award-number":["FUSP-BS-PPC01\/2014"]}],"id":[{"id":"10.13039\/100008049","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Antibiotic resistance (AR) in the environment is of great global concern and a threat to public health. Soil bacteria, including Bacillus spp., could act as recipients and reservoirs of AR genes of clinical, livestock, or agricultural origin. These genes can be shared between bacteria, some of which could be potentially human pathogens. This process can be favored in conditions of abiotic stress, such as heavy metal contamination. The Almad\u00e9n mining district (Ciudad Real, Spain) is one of the environments with the highest mercury (Hg) contamination worldwide. The link between heavy metal contamination and increased AR in environmental bacteria seems clear, due to co-resistance and co-selection phenomena. In the present study, 53 strains were isolated from rhizospheric and bulk soil samples in Almad\u00e9n. AR was tested using Vitek\u00ae 2 and minimum inhibitory concentration (MIC) values were obtained and interpreted based on the criteria of the Clinical and Laboratory Standards Institute (CLSI) guidelines. Based on the resistance profiles, five different antibiotypes were established. The Hg minimum bactericidal concentration (MBC) of each strain was obtained using the plating method with increasing concentrations of HgCl2. A total of 72% of Bacillus spp. showed resistance to two or more commonly used antibiotics. A total of 38 isolates expressed AR to cephalosporins. Finally, the environmental co-selection of AR to cephalosporins and tetracyclines by selective pressure of Hg has been statistically demonstrated.<\/jats:p>","DOI":"10.3390\/ijerph18168304","type":"journal-article","created":{"date-parts":[[2021,8,5]],"date-time":"2021-08-05T09:35:32Z","timestamp":1628156132000},"page":"8304","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Mercury and Antibiotic Resistance Co-Selection in Bacillus sp. Isolates from the Almad\u00e9n Mining District"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8882-372X","authenticated-orcid":false,"given":"Marina","family":"Robas","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical and Health Sciences, Universidad San Pablo CEU, 28668 Boadilla del Monte, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2024-5457","authenticated-orcid":false,"given":"Agust\u00edn","family":"Probanza","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical and Health Sciences, Universidad San Pablo CEU, 28668 Boadilla del Monte, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8221-4584","authenticated-orcid":false,"given":"Daniel","family":"Gonz\u00e1lez","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical and Health Sciences, Universidad San Pablo CEU, 28668 Boadilla del Monte, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0305-6889","authenticated-orcid":false,"given":"Pedro A.","family":"Jim\u00e9nez","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical and Health Sciences, Universidad San Pablo CEU, 28668 Boadilla del Monte, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1111\/j.1469-0691.2008.02679.x","article-title":"Antibiotic resistance genes from the environment: A perspective through newly identified antibiotic resistance mechanisms in the clinical setting","volume":"15","year":"2009","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2893","DOI":"10.1016\/j.envpol.2009.05.051","article-title":"Environmental pollution by antibiotics and by antibiotic resistance determinants","volume":"157","author":"Martinez","year":"2009","journal-title":"Environ. Pollut."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1016\/j.mib.2010.08.005","article-title":"Antibiotic resistance in the environment: A link to the clinic?","volume":"13","author":"Wright","year":"2010","journal-title":"Curr. Opin. Microbiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1038\/nrmicro3439","article-title":"Tackling antibiotic resistance: The environmental framework","volume":"13","author":"Berendonk","year":"2015","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2521","DOI":"10.1098\/rspb.2009.0320","article-title":"The role of natural environments in the evolution of resistance traits in pathogenic bacteria","volume":"276","author":"Martinez","year":"2009","journal-title":"Proc. R. Soc. B Boil. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1126\/science.1120800","article-title":"Sampling the Antibiotic Resistome","volume":"311","author":"McGrann","year":"2006","journal-title":"Science"},{"key":"ref_7","unstructured":"World Health Organization (WHO) (2021, July 10). Global Action Plan on Antimicrobial Resistance. Available online: https:\/\/apps.who.int\/iris\/handle\/10665\/193736."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1916","DOI":"10.3389\/fmicb.2019.01916","article-title":"Bacterial Heavy-Metal and Antibiotic Resistance Genes in a Copper Tailing Dam Area in Northern China","volume":"10","author":"Chen","year":"2019","journal-title":"Front. Microbiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/j.ecss.2012.04.017","article-title":"Chlor-alkali plant contamination of Aussa River sediments induced a large Hg-resistant bacterial community","volume":"113","author":"Baldi","year":"2012","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"144755","DOI":"10.1016\/j.scitotenv.2020.144755","article-title":"A spatial assessment of mercury content in the European Union topsoil","volume":"769","author":"Ballabio","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"6441","DOI":"10.5194\/bg-17-6441-2020","article-title":"A bottom-up quantification of foliar mercury uptake fluxes across Europe","volume":"17","author":"Wohlgemuth","year":"2020","journal-title":"Biogeosciences"},{"key":"ref_12","first-page":"1","article-title":"Neurotoxicity by mercury is not associated with autism spectrum disorders in Spanish children","volume":"46","year":"2020","journal-title":"Ital. J. Pediatr."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2967","DOI":"10.1007\/s00253-016-7364-4","article-title":"Genetic basis and importance of metal resistant genes in bacteria for bioremediation of contaminated environments with toxic metal pollutants","volume":"100","author":"Das","year":"2016","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_14","unstructured":"United Nations Environment Assembly (2021, July 10). Minamata Convention on Mercury. Collection, UN Treaty. Available online: http:\/\/www.mercuryconvention.org\/Convention\/Text."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"S122","DOI":"10.1038\/nm1145","article-title":"Antibacterial resistance worldwide: Causes, challenges and responses","volume":"10","author":"Levy","year":"2004","journal-title":"Nat. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1016\/j.scitotenv.2013.03.071","article-title":"Exploring the links between antibiotic occurrence, antibiotic resistance, and bacterial communities in water supply reservoirs","volume":"456","author":"Huerta","year":"2013","journal-title":"Sci. Total Environ."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2484","DOI":"10.1007\/s11356-016-7997-y","article-title":"Relationship between antibiotic resistance genes and metals in residential soil samples from Western Australia","volume":"24","author":"Knapp","year":"2017","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1176","DOI":"10.1016\/j.scitotenv.2017.10.110","article-title":"Arctic antibiotic resistance gene contamination, a result of anthropogenic activities and natural origin","volume":"621","author":"Tan","year":"2018","journal-title":"Sci. Total Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"465","DOI":"10.1128\/aem.36.3.465-472.1978","article-title":"Heavy-Metal and Antibiotic Resistance in the Bacterial Flora of Sediments of New York Bight","volume":"36","author":"Timoney","year":"1978","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"399","DOI":"10.3389\/fmicb.2012.00399","article-title":"Heavy metal driven co-selection of antibiotic resistance in soil and water bodies impacted by agriculture and aquaculture","volume":"3","author":"Seiler","year":"2012","journal-title":"Front. Microbiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s12864-015-2153-5","article-title":"Co-occurrence of resistance genes to antibiotics, biocides and metals reveals novel insights into their co-selection potential","volume":"16","author":"Pal","year":"2015","journal-title":"BMC Genom."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.1128\/AEM.70.2.1160-1168.2004","article-title":"Integron Diversity in Heavy-Metal-Contaminated Mine Tailings and Inferences about Integron Evolution","volume":"70","author":"Nemergut","year":"2004","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1510","DOI":"10.1111\/j.1462-2920.2006.01091.x","article-title":"Coselection for microbial resistance to metals and antibiotics in freshwater microcosms","volume":"8","author":"Stepanauskas","year":"2006","journal-title":"Environ. Microbiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3896","DOI":"10.1111\/1462-2920.13370","article-title":"Field-based evidence for copper contamination induced changes of antibiotic resistance in agricultural soils","volume":"18","author":"Hu","year":"2016","journal-title":"Environ. Microbiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1016\/j.watres.2016.02.049","article-title":"Co-occurrence of integrase 1, antibiotic and heavy metal resistance genes in municipal wastewater treatment plants","volume":"94","author":"Eckert","year":"2016","journal-title":"Water Res."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1111\/j.1574-6941.2006.00154.x","article-title":"Bacterial tolerances to metals and antibiotics in metal-contaminated and reference streams","volume":"58","author":"Wright","year":"2006","journal-title":"FEMS Microbiol. Ecol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/j.mib.2011.04.010","article-title":"Metagenomic exploration of antibiotic resistance in soil","volume":"14","author":"Monier","year":"2011","journal-title":"Curr. Opin. Microbiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1111\/1462-2920.12631","article-title":"The soil resistome: A critical review on antibiotic resistance origins, ecology and dissemination potential in telluric bacteria","volume":"17","author":"Nesme","year":"2015","journal-title":"Environ. Microbiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1038\/nrmicro1614","article-title":"The antibiotic resistome: The nexus of chemical and genetic diversity","volume":"5","author":"Wright","year":"2007","journal-title":"Nat. Rev. Genet."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1126\/science.1220761","article-title":"The Shared Antibiotic Resistome of Soil Bacteria and Human Pathogens","volume":"337","author":"Forsberg","year":"2012","journal-title":"Science"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"550","DOI":"10.1038\/s41558-020-0759-3","article-title":"The proportion of soil-borne pathogens increases with warming at the global scale","volume":"10","author":"Guerra","year":"2020","journal-title":"Nat. Clim. Chang."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"588","DOI":"10.1111\/nph.16467","article-title":"Soil-borne pathogens as determinants of regeneration patterns at community level in Mediterranean forests","volume":"227","year":"2020","journal-title":"New Phytol."},{"key":"ref_33","first-page":"56","article-title":"Rehabilitaci\u00f3n de suelos contaminados con mercurio: Estrategias aplicables en el \u00e1rea de Almad\u00e9n","volume":"16","author":"Carpena","year":"2007","journal-title":"Ecosistemas"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1556\/ComEc.10.2009.1.13","article-title":"Functional diversity of rhizosphere microorganisms from different genotypes of Arabidopsis thaliana","volume":"10","author":"Velasco","year":"2009","journal-title":"Community Ecol."},{"key":"ref_35","first-page":"72","article-title":"Study of mercury (II) tolerant bacterial isolates from Baghmati River with estimation of plasmid size and growth variation for the high mercury (II) resistant Enterobacter spp.","volume":"3","author":"Mathema","year":"2011","journal-title":"J. Biotechnol. Res."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1128\/jb.173.2.697-703.1991","article-title":"16S ribosomal DNA amplification for phylogenetic study","volume":"173","author":"Weisburg","year":"1991","journal-title":"J. Bacteriol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5463","DOI":"10.1073\/pnas.74.12.5463","article-title":"DNA sequencing with chain-terminating inhibitors","volume":"74","author":"Sanger","year":"1977","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_38","unstructured":"Shannon, C.E., and Weaver, W. (1949). The Mathematical Theory of Communication, The University of Illinois Press."},{"key":"ref_39","unstructured":"Pielou, E.C. (1969). An Introduction to Mathematical Ecology, Wiley."},{"key":"ref_40","unstructured":"Clinical and Laboratory Standards Institute (2016). Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria: Proposed Guideline M45-P, CLSI. [3rd ed.]."},{"key":"ref_41","first-page":"331","article-title":"The prevalence of and resistance to antimicrobial agents of Bacillus cereus isolates from foodstuffs","volume":"48","author":"Brychta","year":"2012","journal-title":"Veterin\u00e1rn\u00ed Med."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/S0378-1097(03)00325-2","article-title":"Diversity of mercury resistance determinants among Bacilluss trains isolated from sediment of Minamata Bay","volume":"223","author":"Narita","year":"2003","journal-title":"FEMS Microbiol. Lett."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1007\/s00248-002-2034-8","article-title":"Predominant Bacillus spp. in Agricultural Soil under Different Management Regimes Detected via PCR-DGGE","volume":"45","author":"Garbeva","year":"2003","journal-title":"Microb. Ecol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1016\/j.jconhyd.2010.12.010","article-title":"Occurrence of steroid hormones and antibiotics in shallow groundwater impacted by livestock waste control facilities","volume":"123","author":"Snow","year":"2011","journal-title":"J. Contam. Hydrol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/j.mib.2011.04.009","article-title":"Antibiotic resistance gene spread due to manure application on agricultural fields","volume":"14","author":"Heuer","year":"2011","journal-title":"Curr. Opin. Microbiol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2276","DOI":"10.1073\/pnas.70.8.2276","article-title":"Aminoglycoside Antibiotic-Inactivating Enzymes in Actinomycetes Similar to Those Present in Clinical Isolates of Antibiotic-Resistant Bacteria","volume":"70","author":"Benveniste","year":"1973","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1016\/j.mib.2007.08.009","article-title":"Expanding the soil antibiotic resistome: Exploring environmental diversity","volume":"10","author":"Griffiths","year":"2007","journal-title":"Curr. Opin. Microbiol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/S0924-8579(00)00144-8","article-title":"Ecological impact of antibiotic use in animals on different complex microflora: Environment","volume":"14","author":"Witte","year":"2000","journal-title":"Int. J. Antimicrob. Agents"},{"key":"ref_49","unstructured":"CLSI (2020). Performance Standards for Antimicrobial Susceptibility Testing: Sixteenth Informational Supplement M100-S16, CLSI."},{"key":"ref_50","unstructured":"(2021). The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters, version 11.0."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1068","DOI":"10.1111\/1462-2920.14526","article-title":"An active \u03b2-lactamase is a part of an orchestrated cell wall stress resistance network of Bacillus subtilis and related rhizosphere species","volume":"21","author":"Bucher","year":"2019","journal-title":"Environ. Microbiol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.scitotenv.2018.09.187","article-title":"The biodegradation of cefuroxime, cefotaxime and cefpirome by the synthetic consortium with probiotic Bacillus clausii and investigation of their potential biodegradation pathways","volume":"651","author":"Kong","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1007\/s10311-016-0587-x","article-title":"Heavy metals and soil microbes","volume":"15","author":"Abdu","year":"2017","journal-title":"Environ. Chem. Lett."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1425","DOI":"10.3389\/fmicb.2018.01425","article-title":"Plant Species and Heavy Metals Affect Biodiversity of Microbial Communities Associated with Metal-Tolerant Plants in Metalliferous Soils","volume":"9","author":"Borymski","year":"2018","journal-title":"Front. Microbiol."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.micpath.2018.10.013","article-title":"New perspectives on Mega plasmid sequence (poh1) in Bacillus thuringiensis ATCC 10792 harbouring antimicrobial, insecticidal and antibiotic resistance genes","volume":"126","author":"Chelliah","year":"2019","journal-title":"Microb. Pathog."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1016\/0966-842X(94)90610-6","article-title":"Epidemiology of tetracycline-resistance determinants","volume":"2","author":"Roberts","year":"1994","journal-title":"Trends Microbiol."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1128\/MMBR.65.2.232-260.2001","article-title":"Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance","volume":"65","author":"Chopra","year":"2001","journal-title":"Microbiol. Mol. Biol. Rev."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"79","DOI":"10.17221\/5681-VETMED","article-title":"Tetracyclines in veterinary medicine and bacterial resistance to them","volume":"49","author":"Michalova","year":"2012","journal-title":"Veterin\u00e1rn\u00ed Med."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1007\/s002849900312","article-title":"The Effect of Longterm Exposure to Mercury on the Bacterial Community in Marine Sediment","volume":"36","author":"Rasmussen","year":"1998","journal-title":"Curr. Microbiol."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1128\/mr.47.3.361-409.1983","article-title":"Plasmid-determined resistance to antimicrobial drugs and toxic metal ions in bacteria","volume":"47","author":"Foster","year":"1983","journal-title":"Microbiol. Rev."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"825","DOI":"10.1128\/AAC.37.4.825","article-title":"Mercury released from dental \u201csilver\u201d fillings provokes an increase in mercury- and antibiotic-resistant bacteria in oral and intestinal floras of primates","volume":"37","author":"Summers","year":"1993","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_62","first-page":"979","article-title":"Heavy metal uptake capacities by the common freshwater green alga Cladophora fracta","volume":"24","author":"Ji","year":"2011","journal-title":"Environ. Boil. Fishes"}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/18\/16\/8304\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:41:07Z","timestamp":1760164867000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/18\/16\/8304"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,5]]},"references-count":62,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["ijerph18168304"],"URL":"https:\/\/doi.org\/10.3390\/ijerph18168304","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,5]]}}}