{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T22:38:25Z","timestamp":1792103905282,"version":"4.4.0"},"reference-count":47,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,5,25]],"date-time":"2020-05-25T00:00:00Z","timestamp":1590364800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>The aim of this study was to analyze the antibacterial activity of four essential oils (EOs), Melaleuca alternifolia, Eucalyptus globulus, Mentha piperita, and Thymus vulgaris, in preventing the development and spread of extended-spectrum \u03b2-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and carbapenemase (KPC)-producing Klebsiella pneumoniae. A total of 60 strains were obtained from the stock collection from the Microbiology Laboratory of Hesperia Hospital, Modena, Italy. Twenty ESBL-producing E. coli, 5 K. pneumoniae, 13 KPC-producing K. pneumoniae, and 20 MBL-producing P. aeruginosa were cultured and reconfirmed as ESBL and carbapenamase producers. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (ESBL and KPC\/MBL). Antibacterial activity of the EOs was determined using the agar disk diffusion assay, and minimal inhibitory concentrations (MICs) were also evaluated. Lastly, adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 24 randomly selected strains. M. alternifolia and T. vulgaris EOs showed the best antibacterial activity against all tested strains and, as revealed by agar disk diffusion assay, M. alternifolia was the most effective, even at low concentrations. This effect was also confirmed by MICs, with values ranging from 0.5 to 16 \u00b5g\/mL and from 1 to 16 \u00b5g\/mL, for M. alternifolia and T. vulgaris EOs, respectively. The EOs\u2019 antibacterial activity compared to antibiotics confirmed M. alternifolia EO as the best antibacterial agent. T. vulgaris EO also showed a good antibacterial activity with MICs lower than both reference antibiotics. Lastly, a significant anti-biofilm activity was observed for the two EOs (*P &lt; 0.05 and **P &lt; 0.01 for M. alternifolia and T. vulgaris EOs, respectively). A good antibacterial and anti-biofilm activity of M. alternifolia and T. vulgaris EOs against all selected strains was observed, thus demonstrating a future possible use of these EOs to treat infections caused by ESBL\/carbapenemase-producing strains, even in association with antibiotics.<\/jats:p>","DOI":"10.3390\/antibiotics9050272","type":"journal-article","created":{"date-parts":[[2020,5,25]],"date-time":"2020-05-25T06:43:40Z","timestamp":1590389020000},"page":"272","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":38,"title":["In Vitro Activity of Essential Oils Against Planktonic and Biofilm Cells of Extended-Spectrum \u03b2-Lactamase (ESBL)\/Carbapenamase-Producing Gram-Negative Bacteria Involved in Human Nosocomial Infections"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3071-3258","authenticated-orcid":false,"given":"Ramona","family":"Iseppi","sequence":"first","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8122-9170","authenticated-orcid":false,"given":"Alessandro","family":"Di Cerbo","sequence":"additional","affiliation":[{"name":"School of Biosciences and Veterinary Medicine, University of Camerino, Via Circonvallazione 93\/95, 62024 Matelica, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Piero","family":"Aloisi","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Chemistry and Microbiology, Hesperia Hospital, Via Arqu\u00e0 80\/A, 1125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3491-0163","authenticated-orcid":false,"given":"Mattia","family":"Manelli","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Chemistry and Microbiology, Hesperia Hospital, Via Arqu\u00e0 80\/A, 1125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3042-4168","authenticated-orcid":false,"given":"Veronica","family":"Pellesi","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8949-1915","authenticated-orcid":false,"given":"Cinzia","family":"Provenzano","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3153-426X","authenticated-orcid":false,"given":"Stefania","family":"Camellini","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2452-5763","authenticated-orcid":false,"given":"Patrizia","family":"Messi","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3221-5172","authenticated-orcid":false,"given":"Carla","family":"Sabia","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,25]]},"reference":[{"key":"ref_1","first-page":"e1403","article-title":"A Review on Antibiotic Resistance: Alarm Bells are Ringing","volume":"9","author":"Zaman","year":"2017","journal-title":"Cureus"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Iseppi, R., Di Cerbo, A., Messi, P., and Sabia, C. (2020). Antibiotic Resistance and Virulence Traits in Vancomycin-Resistant Enterococci (VRE) and Extended-Spectrum beta-Lactamase\/AmpC-producing (ESBL\/AmpC) Enterobacteriaceae from Humans and Pets. Antibiotics (Basel), 9.","DOI":"10.3390\/antibiotics9040152"},{"key":"ref_3","first-page":"395","article-title":"Unusual antibiotic presence in gym trained subjects with food intolerance; a case report","volume":"30","author":"Canello","year":"2014","journal-title":"Nutr. Hosp."},{"key":"ref_4","first-page":"1427","article-title":"Antibiotic treatments in zootechnology and effects induced on the food chain of domestic species and, comparatively, the human specie","volume":"29","author":"Palmieri","year":"2014","journal-title":"Nutr. Hosp."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1619","DOI":"10.1099\/jmm.0.46747-0","article-title":"The diversity of definitions of multidrug-resistant (MDR) and pandrug-resistant (PDR) Acinetobacter baumannii and Pseudomonas aeruginosa","volume":"55","author":"Falagas","year":"2006","journal-title":"J. Med. Microbiol."},{"key":"ref_6","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_7","doi-asserted-by":"crossref","first-page":"672","DOI":"10.1128\/MMBR.64.4.672-693.2000","article-title":"Molecular properties of bacterial multidrug transporters","volume":"64","author":"Putman","year":"2000","journal-title":"Microbiol. Mol. Biol. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1007\/s12079-019-00516-8","article-title":"Virulence of Pseudomonas aeruginosa exposed to carvacrol: Alterations of the Quorum sensing at enzymatic and gene levels","volume":"13","author":"Nazzaro","year":"2019","journal-title":"J. Cell Commun. Signal"},{"key":"ref_9","first-page":"1022","article-title":"Association between biofilm formation of Pseudomonas aeruginosa clinical isolates versus antibiotic resistance and genes involved with biofilm","volume":"6","author":"Maita","year":"2014","journal-title":"J. Chem. Pharm. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"981","DOI":"10.1111\/1469-0691.12651","article-title":"Antimicrobial susceptibility testing in biofilm-growing bacteria","volume":"20","author":"Macia","year":"2014","journal-title":"Clin. Microbiol. Infect"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"53","DOI":"10.2174\/1874285801711010053","article-title":"Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents","volume":"11","author":"Singh","year":"2017","journal-title":"Open Microbiol. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/j.ijfoodmicro.2004.03.022","article-title":"Essential oils: Their antibacterial properties and potential applications in foods\u2014A review","volume":"94","author":"Burt","year":"2004","journal-title":"Int. J. Food Microbiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1590\/S1678-91992010000300006","article-title":"Biological properties of medicinal plants: A review of their antimicrobial activity","volume":"16","author":"Silva","year":"2010","journal-title":"J. Venom. Anim. Toxins Incl. Tropical Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"M379","DOI":"10.1111\/j.1750-3841.2009.01287.x","article-title":"Evaluation of combined antibacterial effects of eugenol, cinnamaldehyde, thymol, and carvacrol against E. coli with an improved method","volume":"74","author":"Pei","year":"2009","journal-title":"J. Food Sci."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Aelenei, P., Miron, A., Trifan, A., Bujor, A., Gille, E., and Aprotosoaie, A.C. (2016). Essential Oils and Their Components as Modulators of Antibiotic Activity against Gram-Negative Bacteria. Medicines (Basel), 3.","DOI":"10.3390\/medicines3030019"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1111\/jam.13755","article-title":"Combination of essential oil and ciprofloxacin to inhibit\/eradicate biofilms in multidrug-resistant Klebsiella pneumoniae","volume":"125","author":"Mohamed","year":"2018","journal-title":"J. Appl. Microbiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"292","DOI":"10.12692\/ijb\/12.4.292-301","article-title":"Screening for antibacterial activity of some essential oils and evaluation of their synergistic effec","volume":"12","author":"Nouzha","year":"2018","journal-title":"Int. J. Biosci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"212","DOI":"10.5455\/jice.20160331064446","article-title":"In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates","volume":"5","author":"Sakkas","year":"2016","journal-title":"J. Intercult. Ethnopharmacol."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Valdivieso-Ugarte, M., Gomez-Llorente, C., Plaza-Diaz, J., and Gil, A. (2019). Antimicrobial, Antioxidant, and Immunomodulatory Properties of Essential Oils: A Systematic Review. Nutrients, 11.","DOI":"10.3390\/nu11112786"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Iseppi, R., Brighenti, V., Licata, M., Lambertini, A., Sabia, C., Messi, P., Pellati, F., and Benvenuti, S. (2019). Chemical Characterization and Evaluation of the Antibacterial Activity of Essential Oils from Fibre-Type Cannabis sativa L. (Hemp). Molecules, 24.","DOI":"10.3390\/molecules24122302"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1080\/14786419.2018.1490904","article-title":"Antimicrobial activity of spices essential oils and its effectiveness on mature biofilms of human pathogens","volume":"34","author":"Condo","year":"2020","journal-title":"Nat. Prod. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"710","DOI":"10.1016\/j.phymed.2013.02.013","article-title":"Combination of essential oils and antibiotics reduce antibiotic resistance in plasmid-conferred multidrug resistant bacteria","volume":"20","author":"Yap","year":"2013","journal-title":"Phytomedicine"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"57","DOI":"10.4103\/phrev.phrev_21_17","article-title":"Developing New Antimicrobial Therapies: Are Synergistic Combinations of Plant Extracts\/Compounds with Conventional Antibiotics the Solution?","volume":"11","author":"Cheesman","year":"2017","journal-title":"Pharmacogn. Rev."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"172","DOI":"10.4103\/0973-1296.66930","article-title":"Antimicrobial and antifungal properties of the essential oil and methanol extracts of Eucalyptus largiflorens and Eucalyptus intertexta","volume":"6","author":"Ahd","year":"2010","journal-title":"Pharmacogn. Mag."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1080\/14786419.2014.954246","article-title":"Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria","volume":"29","author":"Zahlane","year":"2015","journal-title":"Nat. Prod. Res."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Predoi, D., Iconaru, S.L., Buton, N., Badea, M.L., and Marutescu, L. (2018). Antimicrobial Activity of New Materials Based on Lavender and Basil Essential Oils and Hydroxyapatite. Nanomaterials (Basel), 8.","DOI":"10.3390\/nano8050291"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1111\/jam.13490","article-title":"Prevention, removal and inactivation of Escherichia coli and Staphylococcus aureus biofilms using selected monoterpenes of essential oils","volume":"123","author":"Borges","year":"2017","journal-title":"J. Appl. Microbiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.micpath.2018.02.005","article-title":"Drug resistance profile and molecular characterization of extended spectrum beta-lactamase (ESbetaL)-producing Pseudomonas aeruginosa isolated from burn wound infections. Essential oils and their potential for utilization","volume":"116","author":"Ali","year":"2018","journal-title":"Microb. Pathog"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"103377","DOI":"10.1016\/j.fm.2019.103377","article-title":"Quercetin repressed the stress response factor (sigB) and virulence genes (prfA, actA, inlA, and inlC), lower the adhesion, and biofilm development of L. monocytogenes","volume":"87","year":"2020","journal-title":"Food Microbiol."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Ortega-Ramirez, L.A., Guti\u00e9rrez-Pacheco, M.M., Vargas-Arispuro, I., Gonz\u00e1lez-Aguilar, G.A., Mart\u00ednez-T\u00e9llez, M.A., and Ayala-Zavala, J.F. (2020). Inhibition of Glucosyltransferase Activity and Glucan Production as an Antibiofilm Mechanism of Lemongrass Essential Oil against Escherichia coli O157:H7. Antibiotics, 9.","DOI":"10.3390\/antibiotics9030102"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"706","DOI":"10.3389\/fmicb.2014.00706","article-title":"Flipping the switch: Tools for detecting small molecule inhibitors of staphylococcal virulence","volume":"5","author":"Quave","year":"2014","journal-title":"Front Microbiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1128\/CMR.19.1.50-62.2006","article-title":"Melaleuca alternifolia (Tea Tree) oil: A review of antimicrobial and other medicinal properties","volume":"19","author":"Carson","year":"2006","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Oliva, A., Costantini, S., De Angelis, M., Garzoli, S., Bozovic, M., Mascellino, M.T., Vullo, V., and Ragno, R. (2018). High Potency of Melaleuca alternifolia Essential Oil against Multi-Drug Resistant Gram-Negative Bacteria and Methicillin-Resistant Staphylococcus aureus. Molecules, 23.","DOI":"10.3390\/molecules23102584"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1177\/039463200601900309","article-title":"Melaleuca alternifolia essential oil possesses potent anti-staphylococcal activity extended to strains resistant to antibiotics","volume":"19","author":"Ferrini","year":"2006","journal-title":"Int. J. Immunopathol. Pharmacol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"133","DOI":"10.2174\/157489112801619665","article-title":"Recent Patents Regarding Essential Oils and the Significance of their Con-stituents in Human Health and Treatment","volume":"7","author":"Sienkiewicz","year":"2012","journal-title":"Recent Patents Anti-Infective Drug Discov."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Chouhan, S., Sharma, K., and Guleria, S. (2017). Antimicrobial Activity of Some Essential Oils-Present Status and Future Perspectives. Medicines (Basel), 4.","DOI":"10.3390\/medicines4030058"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/j.jcms.2012.10.012","article-title":"The ongoing battle against multi-resistant strains: In-vitro inhibition of hospital-acquired MRSA, VRE, Pseudomonas, ESBL E. coli and Klebsiella species in the presence of plant-derived antiseptic oils","volume":"41","author":"Warnke","year":"2013","journal-title":"J. Craniomaxillofac Surg."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1007\/s10298-007-0265-z","article-title":"Huiles essentielles et bact\u00e9ries r\u00e9sistantes aux antibiotiques","volume":"5","year":"2007","journal-title":"Phytoth\u00e9rapie"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.ijpharm.2014.12.069","article-title":"Essential oils: From extraction to encapsulation","volume":"483","author":"Miladi","year":"2015","journal-title":"Int. J. Pharm."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2647","DOI":"10.1080\/14786419.2018.1466124","article-title":"Antibacterial activity of Thymus vulgaris essential oil alone and in combination with cefotaxime against blaESBL producing multidrug resistant Enterobacteriaceae isolates","volume":"33","author":"Benameur","year":"2019","journal-title":"Nat. Prod. Res."},{"key":"ref_41","unstructured":"CLSI (2019). Performance Standards for Antimicrobial Susceptibility Testing, Clinical and Laboratory Standards Institute. [29th ed.]."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2153","DOI":"10.1128\/JCM.40.6.2153-2162.2002","article-title":"Detection of plasmid-mediated AmpC beta-lactamase genes in clinical isolates by using multiplex PCR","volume":"40","author":"Hanson","year":"2002","journal-title":"J. Clin. Microbiol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"181","DOI":"10.3947\/ic.2009.41.3.181","article-title":"Rapid Detection of Extended Spectrum \u03b2-Lactamase (ESBL) for Enterobacteriaceae by use of a Multiplex PCR-based Method","volume":"41","author":"Kim","year":"2009","journal-title":"Infect Chemother."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"718","DOI":"10.1128\/JCM.01773-10","article-title":"How to detect NDM-1 producers","volume":"49","author":"Nordmann","year":"2011","journal-title":"J. Clin. Microbiol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1016\/j.mimet.2010.02.004","article-title":"Evaluation of diffusion and dilution methods to determine the antibacterial activity of plant extracts","volume":"81","author":"Klancnik","year":"2010","journal-title":"J. Microbiol. Methods"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1016\/j.foodcont.2003.08.009","article-title":"Biological activities of the essential oils and methanol extract of Origanum vulgare ssp. vulgare in the Eastern Anatolia region of Turkey","volume":"15","author":"Daferera","year":"2004","journal-title":"Food Control"},{"key":"ref_47","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":"Stepanovic","year":"2007","journal-title":"APMIS"}],"container-title":["Antibiotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6382\/9\/5\/272\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:32:09Z","timestamp":1760175129000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6382\/9\/5\/272"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,5,25]]},"references-count":47,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["antibiotics9050272"],"URL":"https:\/\/doi.org\/10.3390\/antibiotics9050272","relation":{},"ISSN":["2079-6382"],"issn-type":[{"value":"2079-6382","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,5,25]]}}}