{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T01:55:13Z","timestamp":1773971713401,"version":"3.50.1"},"reference-count":27,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,9,27]],"date-time":"2021-09-27T00:00:00Z","timestamp":1632700800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>This study reported the volatile profile, the antimicrobial activity and the synergistic potential of essential oil (EO) from the Moroccan endemic Thymus atlanticus (Ball) Roussine, in combination with the antibiotics ciprofloxacin and fluconazole for the first time, to the best of our knowledge. The EO chemical composition was determined by gas chromatography coupled to mass spectrometry (GC-MS) analysis and the antimicrobial activity assessed by the disc diffusion method against three Gram positive (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus) and three Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and one clinical isolate, Klebsiella pneumonia). The antifungal activity was evaluated in four pathogenic yeasts (Candida albicans, C. glabrata, C. krusei and C. parapsilosis). The minimum inhibition concentration (MIC) and the synergistic effect with ciprofloxacin and fluconazole were determined by the two-fold dilution technique and checkerboard test, respectively. Twenty-one constituents were identified by GC-MS in the EO, including carvacrol (21.62%) and borneol (21.13%) as the major components. The EO exhibited a significant antimicrobial activity with inhibition zones ranging from 0.7 mm to 22 mm for P. aeruginosa and B. subtilis, respectively, and MIC values varying from 0.56 mg\/mL to 4.47 mg\/mL. The fractional inhibitory concentration index (FICI) values ranged from 0.25 to 0.50 for bacteria and from 0.25 to 0.28 for yeasts. The maximum synergistic effect was observed for K. pneumonia with a 256-fold gain of antibiotic MIC. Our results have suggested that EO from T. atlanticus may be used alone or in association with antibiotics as a new potential alternative to prevent and control the emergence of resistant microbial strains both in the medical field and in the food industry.<\/jats:p>","DOI":"10.3390\/molecules26195850","type":"journal-article","created":{"date-parts":[[2021,9,27]],"date-time":"2021-09-27T21:40:30Z","timestamp":1632778830000},"page":"5850","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["New Insight into the Chemical Composition, Antimicrobial and Synergistic Effects of the Moroccan Endemic Thymus atlanticus (Ball) Roussine Essential Oil in Combination with Conventional Antibiotics"],"prefix":"10.3390","volume":"26","author":[{"given":"Ahmed","family":"Nafis","sequence":"first","affiliation":[{"name":"Microbiology, Health and Environment Team, Faculty of Sciences, Choua\u00efb Doukkali University, El Jadida 24000, Morocco"},{"name":"Laboratory of Microbial Biotechnologies, Agrosciences and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech 40000, Morocco"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5063-1236","authenticated-orcid":false,"given":"Marcello","family":"Iriti","sequence":"additional","affiliation":[{"name":"Department of Agricultural and Environmental Sciences, Milan State University, via G. Celoria 2, 20133 Milan, Italy"}]},{"given":"Lahcen","family":"Ouchari","sequence":"additional","affiliation":[{"name":"Moroccan Coordinated Collection of Microorganisms (CCMM), National Center for Scientific and Technical Research (CNRST), P.O. Box 8027, Rabat 10102, Morocco"}]},{"given":"Fatima","family":"El Otmani","sequence":"additional","affiliation":[{"name":"Microbiology, Health and Environment Team, Faculty of Sciences, Choua\u00efb Doukkali University, El Jadida 24000, Morocco"}]},{"given":"Najat","family":"Marraiki","sequence":"additional","affiliation":[{"name":"Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3664-7853","authenticated-orcid":false,"given":"Abdallah M.","family":"Elgorban","sequence":"additional","affiliation":[{"name":"Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia"}]},{"given":"Asad","family":"Syed","sequence":"additional","affiliation":[{"name":"Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia"}]},{"given":"Noureddine","family":"Mezrioui","sequence":"additional","affiliation":[{"name":"Laboratory of Microbial Biotechnologies, Agrosciences and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech 40000, Morocco"}]},{"given":"Lahcen","family":"Hassani","sequence":"additional","affiliation":[{"name":"Laboratory of Microbial Biotechnologies, Agrosciences and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech 40000, Morocco"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4338-7703","authenticated-orcid":false,"given":"Lu\u00edsa","family":"Cust\u00f3dio","sequence":"additional","affiliation":[{"name":"Center of Marine Sciences, Faculty of Sciences and Technology, University of Algarve, Ed. 7, Campus of Gambelas, 8005-139 Faro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,27]]},"reference":[{"key":"ref_1","first-page":"636","article-title":"Flore pratique du Maroc, Manuel de d\u00e9termination des plantes vasculaires","volume":"2","author":"Fennane","year":"2007","journal-title":"Inst. 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