{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T15:14:05Z","timestamp":1786115645345,"version":"build-2736575974"},"reference-count":45,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T00:00:00Z","timestamp":1785801600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Antimicrobial resistance (AMR) is a major public health concern, and wastewater monitoring can complement clinical surveillance by capturing resistance signals at the population level. This exploratory study assessed selected antibiotic-resistant bacteria and antimicrobial resistance genes (ARGs) in untreated influent wastewater from the municipal wastewater treatment plant of Patras, Greece. Escherichia coli, Pseudomonas aeruginosa, and Enterococcus spp. were isolated using culture-based methods, tested for antimicrobial susceptibility by disk diffusion and Etest according to EUCAST epidemiological cut-off values, and screened by real-time PCR for intI1, sul1, qnrS1, blaTEM, blaVIM, vanA, and ermB. Among 16 E. coli isolates, non-wild-type (non-WT) profiles were detected on 14\/16 for meropenem and 15\/16 for ciprofloxacin, whereas only 1\/16 was non-WT for ampicillin. All 13 P. aeruginosa isolates were wild type (WT) for meropenem but non-WT for ciprofloxacin, while all 17 Enterococcus spp. isolates were WT for vancomycin and ampicillin. Molecular screening showed that blaTEM was the most frequently detected gene in E. coli, while intI1 and sul1 were detected in subsets of P. aeruginosa isolates. No targeted ARGs were detected in Enterococcus spp. These findings provide preliminary, site-specific baseline information on selected AMR phenotypes and genetic determinants in wastewater-derived bacterial isolates from Patras.<\/jats:p>","DOI":"10.3390\/microorganisms14081714","type":"journal-article","created":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T16:30:52Z","timestamp":1785861052000},"page":"1714","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Baseline Investigation of Non-Wild-Type Bacterial Indicators and Antibiotic Resistance Genes in Urban Wastewater from Patras, Greece"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-2597-2446","authenticated-orcid":false,"given":"Zoi","family":"Anastopoulou","sequence":"first","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Konstantina","family":"Charalambous","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angelos","family":"Padouvas","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-8957-8029","authenticated-orcid":false,"given":"Rafail","family":"Fokas","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8708-0960","authenticated-orcid":false,"given":"Kalypso-Angeliki","family":"Koukouvini","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Athanasiou","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-7470-8498","authenticated-orcid":false,"given":"Nikolaos","family":"Giormezis","sequence":"additional","affiliation":[{"name":"Department of Microbiology, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1421-0813","authenticated-orcid":false,"given":"Despoina","family":"Gkentzi","sequence":"additional","affiliation":[{"name":"Department of Paediatrics, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4411-3739","authenticated-orcid":false,"given":"Apostolos","family":"Vantarakis","sequence":"additional","affiliation":[{"name":"Laboratory of Public Health, Epidemiology and Quality of Life, School of Medicine, University of Patras, 26504 Patras, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,4]]},"reference":[{"key":"ref_1","first-page":"UW283","article-title":"Why Do We Need Environmental Monitoring for Everglades Restoration?","volume":"2","author":"Mazzotti","year":"2008","journal-title":"EDIS"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"116404","DOI":"10.1016\/j.watres.2020.116404","article-title":"Making waves: Wastewater-based epidemiology for COVID-19\u2014Approaches and challenges for surveillance and prediction","volume":"186","author":"Polo","year":"2020","journal-title":"Water Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1027","DOI":"10.1289\/ehp.11022","article-title":"Estimating community drug abuse by wastewater analysis","volume":"116","author":"Zuccato","year":"2008","journal-title":"Environ. Health Perspect."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Markt, R., Stillebacher, F., N\u00e4gele, F., Kammerer, A., Peer, N., Payr, M., Scheffknecht, C., Dria, S., Draxl-Weiskopf, S., and Mayr, M. (2023). Expanding the Pathogen Panel in Wastewater Epidemiology to Influenza and Norovirus. Viruses, 15.","DOI":"10.3390\/v15020263"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1016\/j.watres.2019.06.039","article-title":"Antibiotic resistance genes in treated wastewater and in the receiving water bodies: A pan-European survey of urban settings","volume":"162","author":"Cacace","year":"2019","journal-title":"Water Res."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/bs.aambs.2016.08.001","article-title":"Pathogen and Particle Associations in Wastewater: Significance and Implications for Treatment and Disinfection Processes","volume":"97","author":"Chahal","year":"2016","journal-title":"Adv. Appl. Microbiol."},{"key":"ref_7","first-page":"743","article-title":"Antimicrobial resistance: One Health approach","volume":"15","year":"2022","journal-title":"Vet. World"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2643","DOI":"10.3390\/ijerph10072643","article-title":"Antimicrobial resistance in the food chain: A review","volume":"10","author":"Verraes","year":"2013","journal-title":"Int. J. Environ. Res. Public Health"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1007\/s41742-025-01027-8","article-title":"Tracking Pharmaceuticals and Illicit Drugs in Urban Wastewater: Drug Consumption Trends in Patras, Greece","volume":"20","author":"Anastopoulou","year":"2026","journal-title":"Int. J. Environ. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3903","DOI":"10.2147\/IDR.S234610","article-title":"Antimicrobial resistance: Implications and costs","volume":"12","author":"Dadgostar","year":"2019","journal-title":"Infect. Drug Resist."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2640","DOI":"10.1093\/jac\/dks261","article-title":"Identification of acquired antimicrobial resistance genes","volume":"67","author":"Zankari","year":"2012","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Singh, A.K., Kaur, R., Verma, S., and Singh, S. (2022). Antimicrobials and Antibiotic Resistance Genes in Water Bodies: Pollution, Risk, and Control. Front. Environ. Sci., 10.","DOI":"10.3389\/fenvs.2022.830861"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"106103","DOI":"10.1016\/j.ejps.2021.106103","article-title":"Antimicrobial resistance: Prevalence, economic burden, mechanisms of resistance and strategies to overcome","volume":"170","author":"Pulingam","year":"2022","journal-title":"Eur. J. Pharm. Sci."},{"key":"ref_14","unstructured":"Mueller, M., and Tainter, C.R. (2023). Escherichia coli infection. StatPearls, StatPearls Publishing. Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK564298\/."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"ARBA-0026-2017","DOI":"10.1128\/microbiolspec.ARBA-0026-2017","article-title":"Antimicrobial resistance in Escherichia coli","volume":"6","author":"Poirel","year":"2018","journal-title":"Microbiol. Spectr."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"113863","DOI":"10.1016\/j.ijheh.2021.113863","article-title":"Antibiotic resistance patterns of Escherichia coli isolates from the clinic through the wastewater pathway","volume":"238","author":"Bojar","year":"2021","journal-title":"Int. J. Hyg. Environ. Health"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.biotechadv.2018.11.013","article-title":"Antibiotic resistance in Pseudomonas aeruginosa: Mechanisms and alternative therapeutic strategies","volume":"37","author":"Pang","year":"2019","journal-title":"Biotechnol. Adv."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"692","DOI":"10.2166\/wh.2022.101","article-title":"Antibiotic resistance of Pseudomonas aeruginosa isolated from hospital wastewater in the Czech Republic","volume":"20","year":"2022","journal-title":"J. Water Health"},{"key":"ref_19","unstructured":"Gilmore, M.S., Clewell, D.B., Ike, Y., and Shankar, N. (2014). Enterococci as indicators of environmental fecal contamination. Enterococci: From Commensals to Leading Causes of Drug Resistant Infection. Massachusetts Eye and Ear Infirmary, Massachusetts Eye and Ear Infirmary. Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK190421\/."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"685","DOI":"10.1128\/MMBR.00023-12","article-title":"Enterococci in the environment","volume":"76","author":"Byappanahalli","year":"2012","journal-title":"Microbiol. Mol. Biol. Rev."},{"key":"ref_21","unstructured":"Gilmore, M.S., Clewell, D.B., Ike, Y., and Shankar, N. (2014). Enterococcal infection\u2014Treatment and antibiotic resistance. Enterococci: From Commensals to Leading Causes of Drug Resistant Infection. Massachusetts Eye and Ear Infirmary, Massachusetts Eye and Ear Infirmary. Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK190420\/."},{"key":"ref_22","unstructured":"World Health Organization (2026, May 01). Antimicrobial Resistance. Available online: https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/antimicrobial-resistance."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1016\/j.scitotenv.2013.01.032","article-title":"Urban wastewater treatment plants as hotspots for antibiotic resistant bacteria and genes spread into the environment: A review","volume":"447","author":"Rizzo","year":"2013","journal-title":"Sci. Total Environ."},{"key":"ref_24","unstructured":"(2014). Water Quality\u2014Enumeration of Escherichia coli and Coliform Bacteria\u2014Part 1: Membrane Filtration Method for Waters with Low Bacterial Background Flora (Standard No. EN ISO 9308-1:2014)."},{"key":"ref_25","unstructured":"(2000). Water Quality\u2014Detection and Enumeration of Intestinal Enterococci\u2014Part 2: Membrane Filtration Method (Standard No. EN ISO 7899-2:2000)."},{"key":"ref_26","unstructured":"(2008). Water Quality\u2014Detection and Enumeration of Pseudomonas aeruginosa\u2014Method by Membrane Filtration (Standard No. EN ISO 16266:2008)."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Sucato, A., Vecchioni, L., Savoca, D., Presentato, A., Arculeo, M., and Alduina, R. (2021). A comparative analysis of aquatic and polyethylene-associated antibiotic-resistant microbiota in the Mediterranean Sea. Biology, 10.","DOI":"10.3390\/biology10030200"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"247","DOI":"10.3831\/KPI.2023.26.3.247","article-title":"Characterization of vancomycin resistant enterococci and drug ligand interaction between vanA of E. faecalis with the bio-compounds from Aegle marmelos","volume":"26","author":"Jayavarsha","year":"2023","journal-title":"J. Pharmacopunct."},{"key":"ref_29","first-page":"122","article-title":"Detection of blaIMP and blaVIM metallo-\u03b2-lactamases genes among Pseudomonas aeruginosa strains","volume":"3","author":"Fallah","year":"2013","journal-title":"Int. J. Burn. Trauma"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2263","DOI":"10.1128\/AAC.45.8.2263-2268.2001","article-title":"Type II topoisomerase mutations in fluoroquinolone-resistant clinical strains of Pseudomonas aeruginosa isolated in 1998 and 1999: Role of target enzyme in mechanism of fluoroquinolone resistance","volume":"45","author":"Akasaka","year":"2001","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_31","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_32","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.tim.2017.09.005","article-title":"Antibiotic-resistance genes in waste water","volume":"26","author":"Karkman","year":"2018","journal-title":"Trends Microbiol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1124","DOI":"10.1038\/s41467-019-08853-3","article-title":"Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage","volume":"10","author":"Hendriksen","year":"2019","journal-title":"Nat. Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1016\/S1473-3099(06)70599-0","article-title":"The worldwide emergence of plasmid-mediated quinolone resistance","volume":"6","author":"Robicsek","year":"2006","journal-title":"Lancet Infect. Dis."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.tim.2013.11.001","article-title":"The role of aquatic ecosystems as reservoirs of antibiotic resistance","volume":"22","author":"Marti","year":"2014","journal-title":"Trends Microbiol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1269","DOI":"10.1038\/ismej.2014.226","article-title":"Using the class 1 integron-integrase gene as a proxy for anthropogenic pollution","volume":"9","author":"Gillings","year":"2015","journal-title":"ISME J."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Pantanella, F., Lekunberri, I., Gagliardi, A., Venuto, G., S\u00e0nchez-Melsi\u00f3, A., Fabiani, M., Balc\u00e1zar, J.L., Schippa, S., De Giusti, M., and Borrego, C. (2020). Effect of urban wastewater discharge on the abundance of antibiotic resistance genes and antibiotic-resistant Escherichia coli in two Italian rivers. Int. J. Environ. Res. Public Health, 17.","DOI":"10.3390\/ijerph17186813"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1047","DOI":"10.1016\/j.scitotenv.2017.06.153","article-title":"Sewers as potential reservoirs of antibiotic resistance","volume":"605\u2013606","author":"Auguet","year":"2017","journal-title":"Sci. Total Environ."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1099\/jmm.0.081802-0","article-title":"Predominance of carbapenem-resistant Pseudomonas aeruginosa isolates carrying blaIMP and blaVIM metallo-\u03b2-lactamases in a major hospital in Costa Rica","volume":"64","author":"Toval","year":"2015","journal-title":"J. Med. Microbiol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.scitotenv.2018.11.427","article-title":"Biofilms in hospital effluents as a potential crossroads for carbapenemase-encoding strains","volume":"657","author":"Ory","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1111\/j.1365-2672.2009.04274.x","article-title":"Characterization of vanA-type Enterococcus faecium isolates from urban and hospital wastewater and pigs","volume":"107","author":"Kotzamanidis","year":"2009","journal-title":"J. Appl. Microbiol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1002\/jobm.201000102","article-title":"Vancomycin-resistant enterococci from Portuguese wastewater treatment plants","volume":"50","author":"Torres","year":"2010","journal-title":"J. Basic Microbiol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1016\/j.scitotenv.2017.07.121","article-title":"Vancomycin-resistant enterococci with vanA gene in treated municipal wastewater and their association with human hospital strains","volume":"609","author":"Oravcova","year":"2017","journal-title":"Sci. Total Environ."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"e00396-24","DOI":"10.1128\/msphere.00396-24","article-title":"High prevalence of the recently identified clonal lineage ST1299\/CT3109 vanA among vancomycin-resistant Enterococcus faecium strains isolated from municipal wastewater","volume":"9","author":"Valenza","year":"2024","journal-title":"mSphere"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"121989","DOI":"10.1016\/j.watres.2024.121989","article-title":"National-scale antimicrobial resistance surveillance in wastewater: A comparative analysis of HT qPCR and metagenomic approaches","volume":"262","author":"Knight","year":"2024","journal-title":"Water Res."}],"container-title":["Microorganisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2607\/14\/8\/1714\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T04:24:05Z","timestamp":1785990245000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2607\/14\/8\/1714"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,4]]},"references-count":45,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["microorganisms14081714"],"URL":"https:\/\/doi.org\/10.3390\/microorganisms14081714","relation":{},"ISSN":["2076-2607"],"issn-type":[{"value":"2076-2607","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,4]]}}}