{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T12:06:26Z","timestamp":1792497986226,"version":"4.5.0"},"reference-count":48,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,9,26]],"date-time":"2025-09-26T00:00:00Z","timestamp":1758844800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004442","name":"Narodowym Centrum Nauki","doi-asserted-by":"publisher","award":["Grant No. 2021\/41\/N\/NZ6\/03305"],"award-info":[{"award-number":["Grant No. 2021\/41\/N\/NZ6\/03305"]}],"id":[{"id":"10.13039\/501100004442","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100009687","name":"Uniwersytet Medyczny im. Piast\u00f3w Slaskich we Wroclawiu","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100009687","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Pharmacol."],"abstract":"<jats:p>The rising interest in essential oils (EOs) as antimicrobial agents demands evaluation frameworks that provide structured, reproducible assessments. In this study, we examined the strain-dependent response of <jats:italic>Pseudomonas aeruginosa<\/jats:italic> to pharmacopoeia-grade Thyme Essential Oil (obtained from <jats:italic>Thymus vulgaris<\/jats:italic> L., TEO) or polyhexamethylene biguanide antiseptic (PHMB) using a panel of ten genetically diversified strains in planktonic and biofilm forms, and by complementary <jats:italic>in vitro<\/jats:italic> models. Chemical composition of TEO was assessed using Gas Chromatography-Mass Spectrometry (GC\u2013MS), and the main components were thymol, p-cymene, and \u03b3-terpinene. Despite uniform test conditions, we observed striking inter-strain variability: TEO Minimal Inhibitory Concentrations (MICs) differed by up to 1,000-fold, and biofilm susceptibility profiles ranged from full tolerance to near-complete eradication. Notably, strains with low metabolic activity and sparse cell populations\u2014but high matrix biomass\u2014exhibited reduced responsiveness to TEO, while susceptibility to PHMB was more consistent, though not absolute. These findings highlight the critical influence of both microbial phenotype and agent formulation on antimicrobial outcomes. Rather than framing EOs as superior or inferior alternatives, our results advocate for their integration into a stewardship paradigm\u2014one that values standardization, model-based evaluation, and informed formulation. In this context, we position essential oil stewardship not as a constraint but as a necessary evolution for their credible inclusion in antimicrobial strategies.<\/jats:p>","DOI":"10.3389\/fphar.2025.1659096","type":"journal-article","created":{"date-parts":[[2025,9,26]],"date-time":"2025-09-26T05:33:57Z","timestamp":1758864837000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["Toward essential oil stewardship: strain-resolved evaluation of thyme oil activity against Pseudomonas aeruginosa"],"prefix":"10.3389","volume":"16","author":[{"given":"Malwina","family":"Bro\u017cyna","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zuzanna","family":"St\u0119pnicka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natalia","family":"Tymi\u0144ska","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bart\u0142omiej","family":"Dudek","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katarzyna","family":"Kapczy\u0144ska","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam","family":"Matkowski","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanfang","family":"Sun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Micha\u0142","family":"Tomczyk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam","family":"Junka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,9,26]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1163","DOI":"10.1016\/j.ijbiomac.2022.08.192","article-title":"A review on biofilms and the currently available antibiofilm approaches: matrix-destabilizing hydrolases and anti-bacterial peptides as promising candidates for the food industries","volume":"219","author":"Akbarian","year":"2022","journal-title":"Int. J. Biol. Macromol."},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1007\/s11101-025-10123-8","article-title":"Essential oils and plant-derived bioactive compounds: a comprehensive review of their therapeutic potential, mechanisms of action, and advances in extraction technologies","author":"Ali","year":"2025","journal-title":"Phytochem. Rev."},{"key":"B3","doi-asserted-by":"publisher","first-page":"313","DOI":"10.1080\/1040841X.2016.1208146","article-title":"Critical review on biofilm methods","volume":"43","author":"Azeredo","year":"2017","journal-title":"Crit. Rev. Microbiol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"441","DOI":"10.1038\/s41579-019-0196-3","article-title":"Definitions and guidelines for research on antibiotic persistence","volume":"17","author":"Balaban","year":"2019","journal-title":"Nat. Rev. Microbiol."},{"key":"B5","doi-asserted-by":"publisher","first-page":"49","DOI":"10.1080\/j157v04n01_07","article-title":"Thyme (Thymus vulgaris L.), thymol","volume":"4","author":"Basch","year":"2004","journal-title":"J. Herb. Pharmacother."},{"key":"B6","doi-asserted-by":"publisher","first-page":"191","DOI":"10.1186\/1471-2180-14-191","article-title":"Collagen and hyaluronan at wound sites influence early polymicrobial biofilm adhesive events","volume":"14","author":"Birkenhauer","year":"2014","journal-title":"BMC Microbiol."},{"key":"B7","doi-asserted-by":"publisher","first-page":"4096","DOI":"10.3390\/molecules27134096","article-title":"Chemical composition and antibacterial activity of liquid and volatile phase of essential oils against planktonic and biofilm-forming cells of Pseudomonas aeruginosa","volume":"27","author":"Bro\u017cyna","year":"2022","journal-title":"Molecules"},{"key":"B8","doi-asserted-by":"publisher","first-page":"2218","DOI":"10.1038\/s41598-024-52424-6","article-title":"The chronic wound milieu changes essential oils\u2019 antibiofilm activity\u2014an in vitro and larval model study","volume":"14","author":"Bro\u017cyna","year":"2024","journal-title":"Sci. Rep."},{"key":"B9","doi-asserted-by":"publisher","first-page":"1469","DOI":"10.1128\/AAC.46.5.1469-1474.2002","article-title":"Interactions between biocide cationic agents and bacterial biofilms","volume":"46","author":"Campanac","year":"2002","journal-title":"Antimicrob. Agents Chemother."},{"key":"B10","doi-asserted-by":"publisher","first-page":"1659","DOI":"10.1007\/s11999-016-4700-z","article-title":"Biofilm antimicrobial susceptibility increases with antimicrobial exposure time","volume":"474","author":"Castaneda","year":"2016","journal-title":"Clin. Orthop. Relat. Res."},{"key":"B11","doi-asserted-by":"publisher","first-page":"e00595-18","DOI":"10.1128\/JB.00595-18","article-title":"Genomic and phenotypic diversity among ten laboratory isolates of Pseudomonas aeruginosa PAO1","volume":"201","author":"Chandler","year":"2019","journal-title":"J. Bacteriol."},{"key":"B12","doi-asserted-by":"publisher","first-page":"133370","DOI":"10.1016\/j.foodchem.2022.133370","article-title":"Biological properties of Thymus zygis essential oil with emphasis on antimicrobial activity and food application","volume":"393","author":"Coimbra","year":"2022","journal-title":"Food Chem."},{"key":"B13","doi-asserted-by":"publisher","first-page":"850","DOI":"10.1016\/j.tim.2019.05.003","article-title":"Antimicrobial tolerance and metabolic adaptations in microbial biofilms","volume":"27","author":"Crabb\u00e9","year":"2019","journal-title":"Trends Microbiol."},{"key":"B14","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1016\/s0167-7012(02)00003-9","article-title":"A comparative evaluation of five typing techniques for determining the diversity of fluorescent pseudomonads","volume":"50","author":"Dawson","year":"2002","journal-title":"J. Microbiol. Methods"},{"key":"B15","doi-asserted-by":"publisher","first-page":"100087","DOI":"10.1016\/j.bioflm.2022.100087","article-title":"Adding a new dimension: multi-level structure and organization of mixed-species Pseudomonas aeruginosa and Staphylococcus aureus biofilms in a 4-D wound microenvironment","volume":"4","author":"Dhekane","year":"2022","journal-title":"Biofilm"},{"key":"B16","doi-asserted-by":"publisher","first-page":"25","DOI":"10.3390\/medicines3040025","article-title":"Essential oils\u2019 chemical characterization and investigation of some biological activities: a critical review","volume":"3","author":"Dhifi","year":"2016","journal-title":"Medicines"},{"key":"B17","doi-asserted-by":"publisher","first-page":"3996","DOI":"10.3390\/ijms22083996","article-title":"In vitro efficacy of bacterial cellulose dressings chemisorbed with antiseptics against biofilm formed by pathogens isolated from chronic wounds","volume":"22","author":"Dydak","year":"2021","journal-title":"Int. J. Mol. Sci."},{"key":"B18","unstructured":"Assessment report on Thymus vulgaris L., Thymus zygis L., aetheroleum\n          \n          \n          2019"},{"key":"B19","doi-asserted-by":"publisher","first-page":"100129","DOI":"10.1016\/j.bioflm.2023.100129","article-title":"Mechanisms of antibiotic resistance in Pseudomonas aeruginosa biofilms","volume":"5","author":"Fern\u00e1ndez-Bill\u00f3n","year":"2023","journal-title":"Biofilm"},{"key":"B20","doi-asserted-by":"publisher","first-page":"1291","DOI":"10.1111\/jam.13253","article-title":"The agar microdilution method \u2013 a new method for antimicrobial susceptibility testing for essential oils and plant extracts","volume":"121","author":"Golus","year":"2016","journal-title":"J. Appl. Microbiol."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1023523","DOI":"10.3389\/fmicb.2022.1023523","article-title":"Pseudomonas aeruginosa reference strains PAO1 and PA14: a genomic, phenotypic, and therapeutic review","volume":"13","author":"Grace","year":"2022","journal-title":"Front. Microbiol."},{"key":"B22","doi-asserted-by":"publisher","first-page":"691","DOI":"10.1016\/S0731-7085(02)00119-X","article-title":"GC\/MS evaluation of thyme (Thymus vulgaris L.) oil composition and variations during the vegetative cycle","volume":"29","author":"Hudaib","year":"2002","journal-title":"J. Pharm. Biomed. Anal."},{"key":"B23","doi-asserted-by":"publisher","first-page":"2784","DOI":"10.3390\/plants13192784","article-title":"Methods for determination of antimicrobial activity of essential oils in vitro\u2014a review","volume":"13","author":"Hulankova","year":"2024","journal-title":"Plants"},{"key":"B24","doi-asserted-by":"crossref","DOI":"10.1007\/978-3-031-66074-0","volume-title":"Antiseptic stewardship: biocide resistance and clinical implications","author":"Kampf","year":"2024"},{"key":"B25","doi-asserted-by":"publisher","first-page":"150","DOI":"10.3389\/fmicb.2011.00150","article-title":"Pseudomonas aeruginosa genomic structure and diversity","volume":"2","author":"Klockgether","year":"2011","journal-title":"Front. Microbiol."},{"key":"B26","doi-asserted-by":"publisher","first-page":"100006","DOI":"10.1016\/j.bioflm.2019.100006","article-title":"Into the well\u2014a close look at the complex structures of a microtiter biofilm and the crystal violet assay","volume":"1","author":"Kragh","year":"2019","journal-title":"Biofilm"},{"key":"B27","doi-asserted-by":"publisher","first-page":"107121","DOI":"10.1016\/j.micpath.2024.107121","article-title":"Galleria mellonella larvae as a model for Helicobacter pylori biofilm formation under antibiotic stress","volume":"198","author":"Krzy\u017cek","year":"2025","journal-title":"Microb. Pathog."},{"key":"B28","doi-asserted-by":"publisher","first-page":"282","DOI":"10.1039\/c4cc07737g","article-title":"Control of nanoparticle penetration into biofilms through surface design","volume":"51","author":"Li","year":"2015","journal-title":"Chem. Commun."},{"key":"B29","doi-asserted-by":"publisher","first-page":"e92","DOI":"10.1016\/j.jhin.2019.04.008","article-title":"Comparative activity of a polyhexanide\u2013betaine solution against biofilms produced by multidrug-resistant bacteria belonging to high-risk clones","volume":"103","author":"Machuca","year":"2019","journal-title":"J. Hosp. Infect."},{"key":"B30","doi-asserted-by":"publisher","first-page":"112","DOI":"10.1016\/j.procbio.2024.05.021","article-title":"Essential oils pharmacological activity: chemical markers, biogenesis, plant sources, and commercial products","volume":"144","author":"Mohammed","year":"2024","journal-title":"Process Biochem."},{"key":"B31","doi-asserted-by":"publisher","first-page":"e1011931","DOI":"10.1371\/journal.ppat.1011931","article-title":"One species, many faces: the underappreciated importance of strain diversity","volume":"20","author":"Nysten","year":"2024","journal-title":"PLoS Pathog."},{"key":"B32","doi-asserted-by":"publisher","first-page":"4517971","DOI":"10.1155\/2017\/4517971","article-title":"Commercial essential oils as potential antimicrobials to treat skin diseases","volume":"2017","author":"Orchard","year":"2017","journal-title":"Evidence-based Complementary Altern. Med."},{"key":"B33","doi-asserted-by":"publisher","first-page":"e00272-17","DOI":"10.1128\/AAC.00272-17","article-title":"Impact of exposure of methicillin-resistant Staphylococcus aureus to polyhexanide in vitro and in vivo","volume":"61","author":"Renzoni","year":"2017","journal-title":"Antimicrob. Agents Chemother."},{"key":"B34","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1007\/s12393-014-9099-2","article-title":"Essential oils: antimicrobial activities, extraction methods, and their modeling","volume":"7","author":"Reyes-Jurado","year":"2015","journal-title":"Food Eng. Rev."},{"key":"B35","doi-asserted-by":"publisher","first-page":"1641","DOI":"10.1080\/10408398.2019.1586641","article-title":"Essential oils in vapor phase as alternative antimicrobials: a review","volume":"60","author":"Reyes-Jurado","year":"2020","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"B36","doi-asserted-by":"publisher","first-page":"418","DOI":"10.1021\/acsmaterialsau.3c00021","article-title":"Bacterial-nanocellulose-based biointerfaces and biomimetic constructs for blood-contacting medical applications","volume":"3","author":"Roberts","year":"2023","journal-title":"ACS Mater. Au"},{"key":"B37","doi-asserted-by":"publisher","first-page":"386","DOI":"10.1006\/jmbi.1997.1186","article-title":"Large genome rearrangements discovered by the detailed analysis of 21 Pseudomonas aeruginosa clone C isolates found in environment and disease habitats","volume":"271","author":"Romling","year":"1997","journal-title":"J. Mol. Biol."},{"key":"B38","doi-asserted-by":"publisher","first-page":"1007","DOI":"10.12688\/f1000research.125074.2","article-title":"Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health","volume":"11","author":"Ruhluel","year":"2022","journal-title":"F1000Res"},{"key":"B39","doi-asserted-by":"publisher","first-page":"1087","DOI":"10.2217\/fmb-2017-0042","article-title":"Phenotypic and genetic heterogeneity within biofilms with particular emphasis on persistence and antimicrobial tolerance","volume":"12","author":"Sadiq","year":"2017","journal-title":"Future Microbiol."},{"key":"B40","doi-asserted-by":"publisher","first-page":"51","DOI":"10.1080\/1040841X.2018.1538934","article-title":"Underscoring interstrain variability and the impact of growth conditions on associated antimicrobial susceptibilities in preclinical testing of novel antimicrobial drugs","volume":"45","author":"Sanchez","year":"2019","journal-title":"Crit. Rev. Microbiol."},{"key":"B41","doi-asserted-by":"publisher","first-page":"1130097","DOI":"10.3389\/fphar.2023.1130097","article-title":"Editorial: bioactive compounds present in essential oils: advances and pharmacological applications","volume":"14","author":"Santana de Oliveira","year":"2023","journal-title":"Front. Pharmacol."},{"key":"B42","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1533\/9780857095671.499","article-title":"Thyme","volume-title":"Handbook of herbs and spices","author":"Stahl-Biskup","year":"2012"},{"key":"B43","doi-asserted-by":"publisher","first-page":"e2203291","DOI":"10.1002\/advs.202203291","article-title":"Biofilms: formation, research models, potential targets, and methods for prevention and treatment","volume":"9","author":"Su","year":"2022","journal-title":"Adv. Sci."},{"key":"B44","unstructured":"EUCAST reading guide for broth microdilution\n          \n          1\n          20\n          \n          2020"},{"key":"B45","unstructured":"EUCAST disk diffusion method for antimicrobial susceptibility testing reading guide\n          \n          1\n          30"},{"key":"B46","unstructured":"European committee on antimicrobial susceptibility testing breakpoint tables for interpretation of MICs and zone diameters\n          \n          1\n          118"},{"key":"B47","article-title":"Quantitative and qualitative assessment methods for biofilm growth: a mini-review","volume":"6","author":"Wilson","year":"2017","journal-title":"Res. Rev. J. Eng. Technol."},{"key":"B48","unstructured":"WHO bacterial priority pathogens list\n          \n          \n          2024"}],"container-title":["Frontiers in Pharmacology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphar.2025.1659096\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,9,26]],"date-time":"2025-09-26T05:34:00Z","timestamp":1758864840000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphar.2025.1659096\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,26]]},"references-count":48,"alternative-id":["10.3389\/fphar.2025.1659096"],"URL":"https:\/\/doi.org\/10.3389\/fphar.2025.1659096","relation":{},"ISSN":["1663-9812"],"issn-type":[{"value":"1663-9812","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,26]]},"article-number":"1659096"}}