{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T22:37:13Z","timestamp":1790116633609,"version":"4.0.1"},"reference-count":46,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,4,6]],"date-time":"2022-04-06T00:00:00Z","timestamp":1649203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Healthy Food and Healthy Life Institute","award":["20SFR-2YR150BJ"],"award-info":[{"award-number":["20SFR-2YR150BJ"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Listeria monocytogenes is a foodborne pathogen that can develop serious invasive infections. Among foodborne pathogens, L. monocytogenes exhibits the highest case fatality despite antibiotic treatment, suggesting the current therapy should be improved. Although ampicillin and gentamicin are used as a combination therapy to treat listeriosis, our results showed there is no synergy between the two antibiotics. We discovered that aqueous extract of licorice generated significant antimicrobial synergy when combined with aminoglycosides, such as gentamicin, in L. monocytogenes. In the presence of 1 mg\/mL licorice extract, for instance, the minimum inhibitory concentration (MIC) of gentamicin was reduced by 32-fold. Moreover, antimicrobial synergy with licorice extract made gentamicin-resistant clinical isolates of L. monocytogenes susceptible to gentamicin. Given the common use of licorice as a food sweetener in Western countries and a herb in Oriental medicine, our findings suggest that licorice extract can be potentially used as an antibiotic adjuvant to improve the efficacy of antimicrobial treatment of listeriosis.<\/jats:p>","DOI":"10.3390\/pathogens11040440","type":"journal-article","created":{"date-parts":[[2022,4,7]],"date-time":"2022-04-07T21:08:22Z","timestamp":1649365702000},"page":"440","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Antimicrobial Synergy between Aminoglycosides and Licorice Extract in Listeria monocytogenes"],"prefix":"10.3390","volume":"11","author":[{"given":"Myungseo","family":"Park","sequence":"first","affiliation":[{"name":"Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liz","family":"Horn","sequence":"additional","affiliation":[{"name":"Public Health Laboratory, Minnesota Department of Health, Saint Paul, MN 55164, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Victoria","family":"Lappi","sequence":"additional","affiliation":[{"name":"Public Health Laboratory, Minnesota Department of Health, Saint Paul, MN 55164, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dave","family":"Boxrud","sequence":"additional","affiliation":[{"name":"Public Health Laboratory, Minnesota Department of Health, Saint Paul, MN 55164, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Craig","family":"Hedberg","sequence":"additional","affiliation":[{"name":"Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6665-5558","authenticated-orcid":false,"given":"Byeonghwa","family":"Jeon","sequence":"additional","affiliation":[{"name":"Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"344","DOI":"10.4315\/0362-028X.JFP-18-158","article-title":"Prevalence of Listeria monocytogenes in select ready-to-eat foods-deli meat, soft cheese, and packaged salad: A systematic review and meta-analysis","volume":"82","author":"Churchill","year":"2019","journal-title":"J. Food Prot."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1093\/infdis\/jir263","article-title":"Deaths associated with bacterial pathogens transmitted commonly through food: Foodborne diseases active surveillance network (FoodNet), 1996\u20132005","volume":"204","author":"Jones","year":"2011","journal-title":"J. Infect. Dis."},{"key":"ref_3","first-page":"1700798","article-title":"Retrospective validation of whole genome sequencing-enhanced surveillance of listeriosis in Europe, 2010 to 2015","volume":"23","author":"Cormican","year":"2018","journal-title":"Eurosurveillance"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"656","DOI":"10.1345\/aph.19315","article-title":"Treatment of listeriosis","volume":"34","author":"Temple","year":"2000","journal-title":"Ann. Pharmacother."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"974","DOI":"10.1093\/ajcp\/72.6.974","article-title":"Listeria monocytogens: Synergistic effects of ampicillin and gentamicin","volume":"72","author":"Azimi","year":"1979","journal-title":"Am. J. Clin. Pathol."},{"key":"ref_6","first-page":"358051","article-title":"What is new in listeriosis?","volume":"2014","year":"2014","journal-title":"BioMed Res. Int."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2243","DOI":"10.1007\/s10096-019-03666-0","article-title":"Antibiotic treatment for invasive nonpregnancy-associated listeriosis and mortality: A retrospective cohort study","volume":"38","author":"Dickstein","year":"2019","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"586548","DOI":"10.3389\/fphar.2020.586548","article-title":"A systematic review of plants with antibacterial activities: A taxonomic and phylogenetic perspective","volume":"11","author":"Chassagne","year":"2021","journal-title":"Front. Pharmacol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Kawacka, I., Olejnik-Schmidt, A., Schmidt, M., and Sip, A. (2020). Natural plant-derived chemical compounds as Listeria monocytogenes inhibitors in vitro and in food model systems. Pathogens, 10.","DOI":"10.3390\/pathogens10010012"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"107729","DOI":"10.1016\/j.biotechadv.2021.107729","article-title":"Plant synthetic biology for producing potent phyto-antimicrobials to combat antimicrobial resistance","volume":"48","author":"Tiwari","year":"2021","journal-title":"Biotechnol. Adv."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Cui, Y., Kim, S.H., Kim, H., Yeom, J., Ko, K., Park, W., and Park, S. (2012). AFM probing the mechanism of synergistic effects of the green tea polyphenol (\u2212)-epigallocatechin-3-gallate (EGCG) with cefotaxime against extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. PLoS ONE, 7.","DOI":"10.1371\/journal.pone.0048880"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1177\/1535370216689828","article-title":"Synergistic antibacterial effects of herbal extracts and antibiotics on methicillin-resistant Staphylococcus aureus: A computational and experimental study","volume":"242","author":"Kuok","year":"2017","journal-title":"Exp. Biol. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1129","DOI":"10.3389\/fmicb.2015.01129","article-title":"Synergistic anti-Campylobacter jejuni activity of fluoroquinolone and macrolide antibiotics with phenolic compounds","volume":"6","author":"Oh","year":"2015","journal-title":"Front. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1585","DOI":"10.2147\/IDR.S305503","article-title":"Coadministration of ginger extract and fluconazole shows a synergistic effect in the treatment of drug-resistant vulvovaginal candidiasis","volume":"14","author":"Khan","year":"2021","journal-title":"Infect. Drug Resist."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"862","DOI":"10.1016\/j.tim.2016.06.009","article-title":"Antibiotic Antibiotic adjuvants: Rescuing antibiotics from resistance","volume":"24","author":"Wright","year":"2016","journal-title":"Trends Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1590","DOI":"10.1021\/acsinfecdis.9b00134","article-title":"Phytochemical-based nanocomposites for the treatment of bacterial biofilms","volume":"5","author":"Li","year":"2019","journal-title":"ACS Infect. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1128\/AAC.37.3.613","article-title":"Reproducibility of the microdilution checkerboard method for antibiotic synergy","volume":"37","author":"Rand","year":"1993","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1320","DOI":"10.1080\/10408398.2012.692127","article-title":"Essential oils as natural food antimicrobial agents: A review","volume":"55","author":"Vergis","year":"2015","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"E2272","DOI":"10.1111\/1750-3841.12659","article-title":"Retardation of Listeria monocytogenes growth in mozzarella cheese using antimicrobial sachets containing rosemary oil and thyme oil","volume":"79","author":"Han","year":"2014","journal-title":"J. Food Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1002\/jsfa.11475","article-title":"Antimicrobial activity of essential oils and natural plant extracts against Listeria monocytogenes in a dry-cured ham-based model","volume":"102","author":"Martin","year":"2022","journal-title":"J. Sci. Food Agric."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1093\/jac\/dkg301","article-title":"Synergy, antagonism, and what the chequerboard puts between them","volume":"52","author":"Odds","year":"2003","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_22","unstructured":"EUCAST (2022, April 05). Europeoan Committee on Antimicrobial Susceptiblity Testing: Breakpoint Tables for Interpreration of MICs and Zone Diameters. Version 11.0. Available online: https:\/\/www.eucast.org\/ast_of_bacteria\/previous_versions_of_documents\/."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1016\/j.jiph.2017.12.007","article-title":"Antibiotic susceptibility of 259 Listeria monocytogenes strains isolated from food, food-processing plants and human samples in Germany","volume":"11","author":"Noll","year":"2018","journal-title":"J. Infect. Public Health"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1038\/nrmicro.2017.126","article-title":"Listeria monocytogenes: Towards a complete picture of its physiology and pathogenesis","volume":"16","author":"Radoshevich","year":"2018","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Khsim, I.E.F., Mohanaraj-Anton, A., Horte, I.B., Lamont, R.F., Khan, K.S., J\u00f8rgensen, J.S., and Amezcua-Prieto, C. (2022). Listeriosis in pregnancy: An umbrella review of maternal exposure, treatment and neonatal complications. BJOG Int. J. Obstet. Gynaecol., 1\u20137.","DOI":"10.1111\/1471-0528.17073"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1089\/fpd.2018.2548","article-title":"Differences among incidence rates of invasive listeriosis in the U.S. FoodNet population by age, sex, race\/ethnicity, and pregnancy status, 2008\u20132016","volume":"16","author":"Pohl","year":"2019","journal-title":"Foodborne Pathog. Dis."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Wu, S., Wu, Q., Zhang, J., Chen, M., Yan, Z.a., and Hu, H. (2015). Listeria monocytogenes prevalence and characteristics in retail raw foods in China. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0136682"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"263","DOI":"10.7861\/clinmedicine.13-3-263","article-title":"Frontline antibiotic therapy","volume":"13","author":"MacGowan","year":"2013","journal-title":"Clin. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"217","DOI":"10.3947\/ic.2019.51.2.217","article-title":"Guideline for the antibiotic use in acute gastroenteritis","volume":"51","author":"Kim","year":"2019","journal-title":"Infec. Chemother."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1002\/phar.1649","article-title":"A review of antibiotic use in pregnancy","volume":"35","author":"Bookstaver","year":"2015","journal-title":"Pharmacotherapy"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1177\/2042018812454322","article-title":"Licorice abuse: Time to send a warning message","volume":"3","author":"Omar","year":"2012","journal-title":"Ther. Adv. Endocrinol. Metab."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1654","DOI":"10.1055\/s-0035-1557893","article-title":"The pharmacological activities of licorice","volume":"81","author":"Yang","year":"2015","journal-title":"Planta Med."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1021\/acs.jnatprod.5b00877","article-title":"Bioactive constituents of Glycyrrhiza uralensis (Licorice): Discovery of the effective components of a traditional herbal medicine","volume":"79","author":"Ji","year":"2016","journal-title":"J. Nat. Prod."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Zeece, M. (2020). Chapter six-Flavors. Introduction to the Chemistry of Food, Academic Press.","DOI":"10.1016\/B978-0-12-809434-1.00006-2"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.antiviral.2009.04.012","article-title":"Glycyrrhizin inhibits influenza A virus uptake into the cell","volume":"83","author":"Wolkerstorfer","year":"2009","journal-title":"Antivir. Res."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"100043","DOI":"10.1016\/j.phyplu.2021.100043","article-title":"The potential of glycyrrhizin and licorice extract in combating COVID-19 and associated conditions","volume":"1","author":"Gomaa","year":"2021","journal-title":"Phytomed. Plus"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1239","DOI":"10.3389\/fimmu.2020.01239","article-title":"Symptomatic protective action of glycyrrhizin (licorice) in COVID-19 Infection?","volume":"11","author":"Murck","year":"2020","journal-title":"Front. Immunol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1128\/AAC.01023-12","article-title":"18\u03b2-Glycyrrhetinic acid inhibits methicillin-resistant Staphylococcus aureus survival and attenuates virulence gene expression","volume":"57","author":"Long","year":"2013","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Yang, S.-Y., Choi, Y.-R., Lee, M.-J., and Kang, M.-K. (2020). Antimicrobial effects against oral pathogens and cytotoxicity of Glycyrrhiza uralensis extract. Plants, 9.","DOI":"10.3390\/plants9070838"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Kim, Y.-R., and Nam, S.-H. (2022). A Randomized, double-blind, placebo-controlled clinical trial of a mouthwash containing Glycyrrhiza uralensis extract for preventing dental daries. Int. J. Environ. Res. Public Health, 19.","DOI":"10.3390\/ijerph19010242"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"a027029","DOI":"10.1101\/cshperspect.a027029","article-title":"Aminoglycosides: An Overview","volume":"6","author":"Krause","year":"2016","journal-title":"Cold Spring Harb. Perspect. Med."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3249","DOI":"10.1128\/AAC.44.12.3249-3256.2000","article-title":"Aminoglycosides: Perspectives on mechanisms of action and resistance and strategies to counter resistance","volume":"44","author":"Kotra","year":"2000","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2489","DOI":"10.3389\/fmicb.2019.02489","article-title":"Antibacterial effect and mode of action of flavonoids from licorice against methicillin-resistant Staphylococcus aureus","volume":"10","author":"Wu","year":"2019","journal-title":"Front. Microbiol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1038\/nprot.2007.521","article-title":"Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances","volume":"3","author":"Wiegand","year":"2008","journal-title":"Nat. Protoc."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1016\/j.jep.2013.04.040","article-title":"Water extract of licorice had anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines","volume":"148","author":"Shieh","year":"2013","journal-title":"J. Ethnopharmacol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1016\/0732-8893(93)90087-N","article-title":"Synergy assessed by checkerboard a critical analysis","volume":"16","author":"Hsieh","year":"1993","journal-title":"Diagn. Microbiol. Infect. Dis."}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/4\/440\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:49:07Z","timestamp":1760136547000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/4\/440"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,6]]},"references-count":46,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,4]]}},"alternative-id":["pathogens11040440"],"URL":"https:\/\/doi.org\/10.3390\/pathogens11040440","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,6]]}}}