{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T00:20:34Z","timestamp":1778545234958,"version":"3.51.4"},"reference-count":42,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,4,30]],"date-time":"2025-04-30T00:00:00Z","timestamp":1745971200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\/MCTES","award":["UIDB\/50006\/2020"],"award-info":[{"award-number":["UIDB\/50006\/2020"]}]},{"name":"FCT\/MCTES","award":["UIDB\/CVT\/00772\/2020"],"award-info":[{"award-number":["UIDB\/CVT\/00772\/2020"]}]},{"name":"FCT\/MCTES","award":["LA\/P\/0059\/2020"],"award-info":[{"award-number":["LA\/P\/0059\/2020"]}]},{"name":"FCT\/MCTES","award":["LA\/P\/0008\/2020"],"award-info":[{"award-number":["LA\/P\/0008\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Introduction: Listeria monocytogenes is the causative agent of listeriosis, a serious infectious disease with one of the highest case fatality rates among foodborne diseases affecting humans. Objectives: This study investigated the prevalence, antimicrobial resistance pattern and biofilm production capacity of L. monocytogenes isolated in meats. Materials: A total of 75 samples were analyzed, including fresh meats and meat preparations, in Northern Portugal. Methods: The strains were identified using morphological and molecular methods. Antimicrobial resistance was determined using the Kirby\u2013Bauer disk diffusion method, against a panel of 12 antibiotics and the presence of the respective antimicrobial resistance genes was investigated by polymerase chain reaction (PCR). The ability to form biofilms was evaluated by the microtiter biofilm assay. Results: The overall prevalence of L. monocytogenes among screened samples was 17.33%. The isolates were resistant to trimethoprim-sulfamethoxazole (85.71%), ciprofloxacin (38.10%), meropenem (33.33%), tetracycline and erythromycin (28.57%), rifampicin (23.81%), and kanamycin (14.29%). Six isolates (28.57%) exhibited a multidrug-resistance profile. All strains showed positive result for the virulence gene specific to listeriolysin O (hlyA). In the genotypic resistance analysis of the strains, the genes identified were tetK (23.81%), aadA, tetL, blaOXA-48 (14.29%), ermC, and msr(A\/B) (4.76%). All isolates had the ability to form biofilms, with no significant differences in biofilm biomass production at 24 h and 48 h. Some of these strains showed a high capacity for biofilm production. Conclusions: These findings raise public health concerns due to resistance to first-line antibiotics and the biofilm-forming capacity of these isolates, which pose risks to the food industry. Enhanced monitoring and surveillance are essential to guide public health strategies in order to mitigate the threat posed by L. monocytogenes in food.<\/jats:p>","DOI":"10.3390\/antibiotics14050454","type":"journal-article","created":{"date-parts":[[2025,4,30]],"date-time":"2025-04-30T05:50:17Z","timestamp":1745992217000},"page":"454","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Antimicrobial Resistance Profile and Biofilm Formation of Listeria monocytogenes Isolated from Meat"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-4806-4455","authenticated-orcid":false,"given":"Joana","family":"Paiva","sequence":"first","affiliation":[{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Animal and Veterinary Research Center (CECAV), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9406-8433","authenticated-orcid":false,"given":"Vanessa","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Department of Genetics and Biotechnology, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Functional Genomics and Proteomics Unit, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Associated Laboratory for Green Chemistry of the Network of Chemistry and Technology (LAQV-REQUIMTE), Department of Chemistry, NOVA School of Science and Technology, Nova University of Lisbon, 1099-085 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0925-689X","authenticated-orcid":false,"given":"Patr\u00edcia","family":"Poeta","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Animal and Veterinary Research Center (CECAV), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1657-0684","authenticated-orcid":false,"given":"Cristina","family":"Saraiva","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Animal and Veterinary Research Center (CECAV), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.ijfoodmicro.2019.05.016","article-title":"Antimicrobial Resistance Profiles of Listeria Monocytogenes Isolated from Chicken Meat in Fukuoka, Japan","volume":"304","author":"Maung","year":"2019","journal-title":"Int. J. Food Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.4315\/JFP-22-090","article-title":"Antibiotic Resistance Profile of Listeria Monocytogenes Recovered from Ready-to-Eat Foods Surveyed in South Africa","volume":"85","author":"Kayode","year":"2022","journal-title":"J. Food Prot."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"53","DOI":"10.35378\/gujs.972909","article-title":"The Determination of Presence of Listeria Monocytogenes in Ground Meat Sold in Istanbul","volume":"36","author":"Uludag","year":"2023","journal-title":"Gazi Univ. J. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Anwar, T.M., Pan, H., Chai, W., Ed-Dra, A., Fang, W., Li, Y., and Yue, M. (2022). Genetic Diversity, Virulence Factors, and Antimicrobial Resistance of Listeria Monocytogenes from Food, Livestock, and Clinical Samples between 2002 and 2019 in China. Int. J. Food Microbiol., 366.","DOI":"10.1016\/j.ijfoodmicro.2022.109572"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"238","DOI":"10.21323\/2414-438X-2022-7-4-238-246","article-title":"Prevalence of Listeria Monocytogenes in Meat Products during 2017\u20132019 Depending on Technological Factors and Seasons","volume":"7","author":"Yushina","year":"2022","journal-title":"Theory Pract. Meat Process."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"e1","DOI":"10.4102\/ojvr.v87i1.1869","article-title":"A Review of Listeria Monocytogenes from Meat and Meat Products: Epidemiology, Virulence Factors, Antimicrobial Resistance and Diagnosis","volume":"87","author":"Matle","year":"2020","journal-title":"Onderstepoort J. Vet. Res."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"European Food Safety Authority (EFSA), and European Centre for Disease Prevention and Control (ECDC) (2024). The European Union One Health 2023 Zoonoses Report. EFSA J., 22, e9106.","DOI":"10.2903\/j.efsa.2024.9106"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Mughini-Gras, L., Paganini, J.A., Guo, R., Coipan, C.E., Friesema, I.H.M., van Hoek, A.H.A.M., van den Beld, M., Kuiling, S., Bergval, I., and Wullings, B. (2025). Source Attribution of Listeria Monocytogenes in the Netherlands. Int. J. Food Microbiol., 427.","DOI":"10.1016\/j.ijfoodmicro.2024.110953"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Liu, Y., Sun, W., Sun, T., Gorris, L.G.M., Wang, X., Liu, B., and Dong, Q. (2020). The Prevalence of Listeria Monocytogenes in Meat Products in China: A Systematic Literature Review and Novel Meta-Analysis Approach. Int. J. Food Microbiol., 312.","DOI":"10.1016\/j.ijfoodmicro.2019.108358"},{"key":"ref_10","first-page":"1487","article-title":"Prevalence of Listeria Monocytogenes in Meat Products Retailed in Egypt and Worldwide: A Review","volume":"13","author":"Nagaty","year":"2023","journal-title":"J. Adv. Vet. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"129477","DOI":"10.1016\/j.jhazmat.2022.129477","article-title":"Evaluation of Culturable \u2018Last-Resort\u2019 Antibiotic Resistant Pathogens in Hospital Wastewater and Implications on the Risks of Nosocomial Antimicrobial Resistance Prevalence","volume":"438","author":"Li","year":"2022","journal-title":"J. Hazard Mater."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Gana, J., Gcebe, N., Moerane, R., Ngoshe, Y.B., Moabelo, K., and Adesiyun, A.A. (2024). Detection of Pathogenic Serogroups and Virulence Genes in Listeria Monocytogenes Strains Isolated from Beef and Beef Products Retailed in Gauteng Province, South Africa, Using Phenotypic and Polymerase Chain Reaction (PCR)-Based Methods. Int. J. Microbiol., 2024.","DOI":"10.1155\/2024\/8891963"},{"key":"ref_13","first-page":"1","article-title":"Persistence of Listeria Monocytogenes in Food Commodities: Foodborne Pathogenesis, Virulence Factors, and Implications for Public Health","volume":"5","author":"Ranasinghe","year":"2021","journal-title":"Food Res."},{"key":"ref_14","unstructured":"Milica, P. (2018, January 23\u201325). The Emphasis of Listeria Monocytogenes in Raw Meat. Proceedings of the 4th International Congress \u201cFood Technology, Quality and Safety\u201d, Novi Sad, Szerbia."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Silva, V., Correia, E., Pereira, J.E., Gonz\u00e1lez-Machado, C., Capita, R., Alonso-Calleja, C., Igrejas, G., and Poeta, P. (2022). Exploring the Biofilm Formation Capacity in S. Pseudintermedius and Coagulase-Negative Staphylococci Species. Pathogens, 11.","DOI":"10.3390\/pathogens11060689"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Panebianco, F., Alvarez-Ord\u00f3\u00f1ez, A., Oliveira, M., Ferreira, S., Lovisolo, S., Vono, C., Cannizzo, F.T., Chiesa, F., Civera, T., and Di Ciccio, P. (2025). Effect of Neutral Electrolyzed Water on Biofilm Formed by Meat-Related Listeria Monocytogenes: Intraspecies Variability and Influence of the Growth Surface Material. Int. J. Food Microbiol., 431.","DOI":"10.1016\/j.ijfoodmicro.2025.111064"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e20180557","DOI":"10.1590\/0001-3765202020180557","article-title":"Identification of Listeria Monocytogenes in Cattle Meat Using Biochemical Methods and Amplification of the Hemolysin Gene","volume":"92","author":"Silva","year":"2020","journal-title":"An. Acad. Bras. Ciencias"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Doijad, S.P., Barbuddhe, S.B., Garg, S., Poharkar, K.V., Kalorey, D.R., Kurkure, N.V., Rawool, D.B., and Chakraborty, T. (2015). Biofilm-Forming Abilities of Listeria Monocytogenes Serotypes Isolated from Different Sources. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0137046"},{"key":"ref_19","unstructured":"EUCAST (2025). Breakpoint Tables for Interpretation of MICs and Zone Diameters, Version 15.0, European Committee on Antimicrobial Susceptibility Testing (EUCAST)."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1111\/j.1469-0691.2011.03570.x","article-title":"Multidrug-Resistant, Extensively Drug-Resistant and Pandrug-Resistant Bacteria: An International Expert Proposal for Interim Standard Definitions for Acquired Resistance","volume":"18","author":"Magiorakos","year":"2012","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Rodr\u00edguez-Melc\u00f3n, C., Esteves, A., Panera-Mart\u00ednez, S., Capita, R., and Alonso-Calleja, C. (2022). Quantification of Total and Viable Cells and Determination of Serogroups and Antibiotic Resistance Patterns of Listeria Monocytogenes in Chicken Meat from the North-Western Iberian Peninsula. Antibiotics, 11.","DOI":"10.3390\/antibiotics11121828"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"551","DOI":"10.4315\/0362-028X.JFP-16-310","article-title":"Genetic Characterization of Listeria Monocytogenes Isolates from Industrial and Retail Ready-to-Eat Meat-Based Foods and Their Relationship with Clinical Strains from Human Listeriosis in Portugal","volume":"80","author":"Henriques","year":"2017","journal-title":"J. Food Prot."},{"key":"ref_23","first-page":"2593","article-title":"Presence and Serological Characteristics of Listeria Monocytogenes in Meat and Meat Products","volume":"6","year":"2012","journal-title":"HealthMED"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/j.rvsc.2022.02.015","article-title":"The Prevalence of Listeria Monocytogenes in Meat Products in Brazil: A Systematic Literature Review and Meta-Analysis","volume":"145","author":"Cavalcanti","year":"2022","journal-title":"Res. Vet. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"74","DOI":"10.18683\/germs.2020.1180","article-title":"Prevalence, Characterization and Antimicrobial Resistance of Listeria Monocytogenes Isolated from Beef Meat in Meknes City, Morocco","volume":"10","author":"Boukili","year":"2020","journal-title":"Germs"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Duma, M.N., Ciupescu, L.M., Dan, S.D., Crisan-Reget, O.L., and Tabaran, A. (2024). Virulence and Antimicrobial Resistance of Listeria Monocytogenes Isolated from Ready-to-Eat Food Products in Romania. Microorganisms, 12.","DOI":"10.3390\/microorganisms12050954"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2537","DOI":"10.4315\/0362-028X-71.12.2537","article-title":"Comparison of Antimicrobial Resistance in Escherichia Coli, Staphylococcus Aureus, and Listeria Monocytogenes Strains Isolated from Organic and Conventional Poultry Meat","volume":"71","author":"Miranda","year":"2008","journal-title":"J. Food Prot."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Kawacka, I., Pietrzak, B., Schmidt, M., and Olejnik-Schmidt, A. (2023). Listeria Monocytogenes Isolates from Meat Products and Processing Environment in Poland Are Sensitive to Commonly Used Antibiotics, with Rare Cases of Reduced Sensitivity to Ciprofloxacin. Life, 13.","DOI":"10.3390\/life13030821"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1089\/fpd.2023.0004","article-title":"Antimicrobial Susceptibility Profile of Listeria Monocytogenes Isolated from Meat Products: A Systematic Review and Meta-Analysis","volume":"20","author":"Tayeb","year":"2023","journal-title":"Foodborne Pathog. Dis."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1016\/j.fct.2019.01.033","article-title":"Importance of Antibiotic Residues in Animal Food","volume":"125","year":"2019","journal-title":"Food Chem. Toxicol."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Gargano, V., Sciortino, S., Gambino, D., Costa, A., Agozzino, V., Reale, S., Alduina, R., and Vicari, D. (2021). Antibiotic Susceptibility Profile and Tetracycline Resistance Genes Detection in Salmonella Spp. Strains Isolated from Animals and Food. Antibiotics, 10.","DOI":"10.3390\/antibiotics10070809"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Silva, A., Silva, V., Gomes, J.P., Coelho, A., Batista, R., Saraiva, C., Esteves, A., Martins, \u00c2., Contente, D., and Diaz-Formoso, L. (2024). Listeria Monocytogenes from Food Products and Food Associated Environments: Antimicrobial Resistance, Genetic Clustering and Biofilm Insights. Antibiotics, 13.","DOI":"10.3390\/antibiotics13050447"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Piechota, M., Kot, B., Frankowska-Maciejewska, A., Gruzewska, A., and Wo\u017aniak-Kosek, A. (2018). Biofilm Formation by Methicillin-Resistant and Methicillin-Sensitive Staphylococcus Aureus Strains from Hospitalized Patients in Poland. Biomed Res. Int., 2018.","DOI":"10.1155\/2018\/4657396"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1111\/j.1600-0463.2007.apm_630.x","article-title":"Quantification of Biofilm in Microtiter Plates: Overview of Testing Conditions and Practical Recommendations for Assessment of Biofilm Production by Staphylococci","volume":"115","author":"Hola","year":"2007","journal-title":"APMIS"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1159\/000494757","article-title":"Influence of Laboratory Culture Media on in Vitro Growth, Adhesion, and Biofilm Formation of Pseudomonas Aeruginosa and Staphylococcus Aureus","volume":"28","author":"Wijesinghe","year":"2019","journal-title":"Med. Princ. Pract."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Liu, L., Ye, C., Soteyome, T., Zhao, X., Xia, J., Xu, W., Mao, Y., Peng, R., Chen, J., and Xu, Z. (2019). Inhibitory Effects of Two Types of Food Additives on Biofilm Formation by Foodborne Pathogens. Microbiologyopen, 8.","DOI":"10.1002\/mbo3.853"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Vargov\u00e1, M., Zigo, F., V\u00fdrostkov\u00e1, J., Farka\u0161ov\u00e1, Z., and Rehan, I.F. (2023). Biofilm-Producing Ability of Staphylococcus Aureus Obtained from Surfaces and Milk of Mastitic Cows. Vet. Sci., 10.","DOI":"10.3390\/vetsci10060386"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Di Ciccio, P., Rubiola, S., Panebianco, F., Lomonaco, S., Allard, M., Bianchi, D.M., Civera, T., and Chiesa, F. (2022). Biofilm Formation and Genomic Features of Listeria Monocytogenes Strains Isolated from Meat and Dairy Industries Located in Piedmont (Italy). Int. J. Food Microbiol., 378.","DOI":"10.1016\/j.ijfoodmicro.2022.109784"},{"key":"ref_39","unstructured":"(2017). Microbiology of the Food Chain\u2014Horizontal Method for the Detection and Enumeration of Listeria spp (Standard No. EN ISO 11290-1:2017)."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Silva, V., Hermenegildo, S., Ferreira, C., Manaia, C.M., Capita, R., Alonso-Calleja, C., Carvalho, I., Pereira, J.E., Maltez, L., and Capelo, J.L. (2020). Genetic Characterization of Methicillin-Resistant Staphylococcus Aureus Isolates from Human Bloodstream Infections: Detection of MLSB Resistance. Antibiotics, 9.","DOI":"10.3390\/antibiotics9070375"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Oniciuc, E.A., Cerca, N., and Nicolau, A.I. (2016). Compositional Analysis of Biofilms Formed by Staphylococcus Aureus Isolated from Food Sources. Front. Microbiol., 7.","DOI":"10.3389\/fmicb.2016.00390"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.mimet.2007.11.010","article-title":"Comparison of Multiple Methods for Quantification of Microbial Biofilms Grown in Microtiter Plates","volume":"72","author":"Peeters","year":"2008","journal-title":"J. Microbiol. Methods"}],"container-title":["Antibiotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6382\/14\/5\/454\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:24:36Z","timestamp":1760030676000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6382\/14\/5\/454"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,30]]},"references-count":42,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2025,5]]}},"alternative-id":["antibiotics14050454"],"URL":"https:\/\/doi.org\/10.3390\/antibiotics14050454","relation":{},"ISSN":["2079-6382"],"issn-type":[{"value":"2079-6382","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,30]]}}}