{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T14:55:37Z","timestamp":1768402537281,"version":"3.49.0"},"reference-count":47,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,3,28]],"date-time":"2021-03-28T00:00:00Z","timestamp":1616889600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Candida albicans and Klebsiella pneumoniae frequently co-exist within the human host as a complex biofilm community. These pathogens are of interest because their association is also related to significantly increased morbidity and mortality in hospitalized patients. With the aim of highlighting metabolic shifts occurring in the dual-species biofilm, an untargeted GC-MS-based metabolomics approach was applied to single and mixed biofilms of C. albicans and K. pneumoniae. Metabolomic results showed that among the extracellular metabolites identified, approximately 40 compounds had significantly changed relative abundance, mainly involving central carbon, amino acid, vitamin, and secondary metabolisms, such as serine, leucine, arabitol, phosphate, vitamin B6, cyclo-(Phe-Pro), trehalose, and nicotinic acid. The results were related to the strict interactions between the two species and the different microbial composition in the early and mature biofilms.<\/jats:p>","DOI":"10.3390\/ijms22073496","type":"journal-article","created":{"date-parts":[[2021,3,28]],"date-time":"2021-03-28T22:09:01Z","timestamp":1616969341000},"page":"3496","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["GC-MS-Based Metabolomics Study of Single- and Dual-Species Biofilms of Candida albicans and Klebsiella pneumoniae"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8116-0839","authenticated-orcid":false,"given":"Emilia","family":"Galdiero","sequence":"first","affiliation":[{"name":"Department of Biology, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8318-3065","authenticated-orcid":false,"given":"Maria Michela","family":"Salvatore","sequence":"additional","affiliation":[{"name":"Department of Chemical Sciences, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4981-8837","authenticated-orcid":false,"given":"Angela","family":"Maione","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5874-3961","authenticated-orcid":false,"given":"Elisabetta","family":"de Alteriis","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8949-3654","authenticated-orcid":false,"given":"Anna","family":"Andolfi","sequence":"additional","affiliation":[{"name":"Department of Chemical Sciences, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"},{"name":"BAT Center\u2014Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples \u2018Federico II\u2019, Portici, 80055 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0212-1271","authenticated-orcid":false,"given":"Francesco","family":"Salvatore","sequence":"additional","affiliation":[{"name":"Department of Chemical Sciences, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6805-0408","authenticated-orcid":false,"given":"Marco","family":"Guida","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Naples \u2018Federico II\u2019, via Cinthia, 80126 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,28]]},"reference":[{"key":"ref_1","unstructured":"Pereira, R., dos Santos Fontenelle, R.O., de Brito, E.H.S., and de Morais, S.M. (2020). Biofilm of Candida albicans: Formation, regulation and resistance. J. Appl. Microbiol., 1\u201312."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fmed.2018.00028","article-title":"Candida Biofilms: Threats, challenges, and promising strategies","volume":"5","author":"Cavalheiro","year":"2018","journal-title":"Front. Med."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Rodrigues, M.E., Gomes, F., and Rodrigues, C.F. (2020). Candida spp.\/bacteria mixed biofilms. J. Fungi, 6.","DOI":"10.3390\/jof6010005"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1128\/CMR.00013-11","article-title":"Polymicrobial interactions: Impact on pathogenesis and human disease","volume":"25","author":"Peters","year":"2012","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Ponde, N.O., Lortal, L., Ramage, G., Naglik, J.R., and Jonathan, P. (2021). Critical reviews in microbiology Candida albicans biofilms and polymicrobial interactions. Crit. Rev. Microbiol., 1\u201321.","DOI":"10.1080\/1040841X.2020.1843400"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Zago, C.E., Silva, S., Sanit\u00e1, P.V., Barbugli, P.A., Dias, C.M.I., Lordello, V.B., and Vergani, C.E. (2015). Dynamics of biofilm formation and the Interaction between Candida albicans and methicillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA). PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0123206"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-020-76744-5","article-title":"Disruption of Streptococcus mutans and Candida albicans synergy by a commensal streptococcus","volume":"10","author":"Huffines","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fmicb.2020.581543","article-title":"Epidemiological characteristics and formation mechanisms of multidrug-resistant hypervirulent Klebsiella pneumoniae","volume":"11","author":"Tang","year":"2020","journal-title":"Front. Microbiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1016\/S1473-3099(17)30753-3","article-title":"Discovery, research, and development of new antibiotics: The WHO priority list of antibiotic-resistant bacteria and tuberculosis","volume":"18","author":"Tacconelli","year":"2018","journal-title":"Lancet Infect. Dis."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e38","DOI":"10.1590\/1807-3107bor-2017.vol31.0038","article-title":"Association between pathogens from tracheal aspirate and oral biofilm of patients on mechanical ventilation","volume":"31","author":"Souza","year":"2017","journal-title":"Braz. Oral Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"37","DOI":"10.4103\/0300-1652.99830","article-title":"Colonization of peripheral intravascular catheters with biofilm producing microbes: Evaluation of risk factors","volume":"53","author":"Singhai","year":"2012","journal-title":"Niger. Med. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"743","DOI":"10.3390\/pathogens3030743","article-title":"Antibiotic resistance related to biofilm formation in Klebsiella pneumoniae","volume":"3","author":"Vuotto","year":"2014","journal-title":"Pathogens"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Galdiero, E., Di Onofrio, V., Maione, A., Gambino, E., Gesuele, R., Menale, B., Ciaravolo, M., Carraturo, F., and Guida, M. (2020). Allium ursinum and allium oschaninii against Klebsiella pneumoniae and Candida albicans mono-and polymicrobic biofilms in in vitro static and dynamic models. Microorganisms, 8.","DOI":"10.3390\/microorganisms8030336"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Maione, A., de Alteriis, E., Carraturo, F., Galdiero, S., Falanga, A., Guida, M., Di Cosmo, A., Maselli, V., and Galdiero, E. (2021). The membranotropic peptide gH625 to combat mixed Candida albicans\/Klebsiella pneumoniae biofilm: Correlation between in vitro anti-biofilm activity and in vivo antimicrobial protection. J. Fungi, 7.","DOI":"10.3390\/jof7010026"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"214","DOI":"10.3390\/pathogens10020214","article-title":"Impact of the peptide WMR-K on dual-Species biofilm Candida albicans\/Klebsiella pneumoniae and on the untargeted metabolomic profile","volume":"10","author":"Galdiero","year":"2021","journal-title":"Pathogens"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1016\/j.jchromb.2016.09.029","article-title":"Sample preparation procedures utilized in microbial metabolomics: An overview","volume":"1043","author":"Patejko","year":"2017","journal-title":"J. Chromatogr. B Anal. Technol. Biomed. Life Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1007\/s11306-018-1391-3","article-title":"Metabolic footprint analysis of metabolites that discriminate single and mixed yeast cultures at two key time-points during mixed culture alcoholic fermentations","volume":"14","author":"Peng","year":"2018","journal-title":"Metabolomics"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/j.micpath.2018.09.027","article-title":"Polymicrobial antibiofilm activity of the membranotropic peptide gH625 and its analogue","volume":"125","author":"Lombardi","year":"2018","journal-title":"Microb. Pathog."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2411","DOI":"10.1016\/j.cub.2014.08.057","article-title":"Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures","volume":"24","author":"Fox","year":"2014","journal-title":"Curr. Biol."},{"key":"ref_20","unstructured":"AMDIS (2021, February 09). Available online: www.amdis.net."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"966","DOI":"10.1021\/ac0614846","article-title":"Systematic identification of conserved metabolites in GC\/MS data for metabolomics and biomarker discovery","volume":"79","author":"Styczynski","year":"2007","journal-title":"Anal. Chem."},{"key":"ref_22","unstructured":"MATLAB (2020, December 01). Available online: www.mathworks.com."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.marchem.2018.08.003","article-title":"GC\u2013MS approaches for the screening of metabolites produced by marine-derived Aspergillus","volume":"206","author":"Salvatore","year":"2018","journal-title":"Mar. Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"126346","DOI":"10.1016\/j.micres.2019.126346","article-title":"Altered metabolomic profile of dual-species biofilm: Interactions between Proteus mirabilis and Candida albicans","volume":"230","author":"Kart","year":"2020","journal-title":"Microbiol. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1086\/599838","article-title":"Time course global gene expression analysis of an in vivo Candida biofilm","volume":"200","author":"Nett","year":"2009","journal-title":"J. Infect. Dis."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2375","DOI":"10.1021\/pr300447k","article-title":"Time course analysis of Candida albicans metabolites during biofilm development","volume":"12","author":"Zhu","year":"2013","journal-title":"J. Proteome Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.tim.2004.11.006","article-title":"Biofilms: The matrix revisited","volume":"13","author":"Branda","year":"2005","journal-title":"Trends Microbiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s11157-015-9385-3","article-title":"Bacterial l-leucine catabolism as a source of secondary metabolites","volume":"15","year":"2016","journal-title":"Rev. Environ. Sci. Biotechnol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1334","DOI":"10.1016\/j.bbrc.2012.10.118","article-title":"Specific stress-induced storage of trehalose, glycerol and d-arabitol in response to oxidative and osmotic stress in Candida albicans","volume":"430","year":"2013","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1111\/jam.12807","article-title":"Production of arabitol by yeasts: Current status and future prospects","volume":"119","year":"2015","journal-title":"J. Appl. Microbiol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"866","DOI":"10.1126\/science.1108640","article-title":"Nicotinic acid limitation regulates silencing of Candida adhesins during UTI","volume":"308","author":"Domergue","year":"2005","journal-title":"Science"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1111\/j.1365-2958.2007.05886.x","article-title":"Assimilation of NAD+ precursors in Candida glabrata","volume":"66","author":"Ma","year":"2007","journal-title":"Mol. Microbiol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"449","DOI":"10.3349\/ymj.2014.55.2.449","article-title":"Influence of bacterial presence on biofilm formation of Candida albicans","volume":"55","author":"Park","year":"2014","journal-title":"Yonsei Med. J."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1150","DOI":"10.1128\/IAI.02878-14","article-title":"Cyclo(Phe-Pro) produced by the human pathogen Vibrio vulnificus inhibits host innate immune responses through the NF-\u03baB pathway","volume":"83","author":"Kim","year":"2015","journal-title":"Infect. Immun."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Salvatore, M.M., F\u00e9lix, C., Lima, F., Ferreira, V., Duarte, A.S., Salvatore, F., Alves, A., Esteves, A.C., and Andolfi, A. (2020). Effect of \u03b3-aminobutyric acid (GABA) on the metabolome of two strains of Lasiodiplodia theobromae isolated from grapevine. Molecules, 25.","DOI":"10.3390\/molecules25173833"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Salvatore, M.M., DellaGreca, M., Nicoletti, R., Salvatore, F., Vinale, F., Naviglio, D., and Andolfi, A. (2018). Talarodiolide, a new 12-membered macrodiolide, and GC\/MS investigation of culture filtrate and mycelial extracts of Talaromyces pinophilus. Molecules, 23.","DOI":"10.3390\/molecules23040950"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"329","DOI":"10.3390\/molecules14010329","article-title":"Vitamin B6: A long known compound of surprising complexity","volume":"14","author":"Mooney","year":"2009","journal-title":"Molecules"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1016\/S0278-6915(02)00011-X","article-title":"Trehalose: A review of properties, history of use and human tolerance, and results of multiple safety studies","volume":"40","author":"Richards","year":"2002","journal-title":"Food Chem. Toxicol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2599","DOI":"10.1099\/00221287-148-8-2599","article-title":"Protective role of trehalose during severe oxidative stress caused by hydrogen peroxide and the adaptive oxidative stress response in Candida albicans","volume":"148","author":"Zaragoza","year":"2002","journal-title":"Microbiology"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2921","DOI":"10.1021\/pr4002178","article-title":"Effect of amphotericin B on the metabolic profiles of Candida albicans","volume":"12","author":"Cao","year":"2013","journal-title":"J. Proteome Res."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1128\/mr.48.1.42-59.1984","article-title":"Regulation of trehalose mobilization in fungi","volume":"48","author":"Thevelein","year":"1984","journal-title":"Microbiol. Rev."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"846","DOI":"10.1080\/08927014.2020.1824272","article-title":"Enterococcus faecalis inhibits Klebsiella pneumoniae growth in polymicrobial biofilms in a glucose-enriched medium","volume":"36","author":"Ratia","year":"2020","journal-title":"Biofouling"},{"key":"ref_43","first-page":"1","article-title":"A strategy for GC\/MS quantification of polar compounds via their silylated surrogates: Silylation and quantification of biological amino acids","volume":"6","author":"Guida","year":"2015","journal-title":"J. Anal. Bioanal. Tech."},{"key":"ref_44","unstructured":"(2021, February 09). NIST 14, Available online: https:\/\/www.nist.gov\/srd\/nist-standard-reference-database-1a."},{"key":"ref_45","unstructured":"(2021, February 09). Golm Metabolome Database. Available online: http:\/\/gmd.mpimp-golm.mpg.de\/."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1007\/s11306-010-0198-7","article-title":"Decision tree supported substructure prediction of metabolites from GC-MS profiles","volume":"6","author":"Hummel","year":"2010","journal-title":"Metabolomics"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"202","DOI":"10.1016\/j.chroma.2014.02.049","article-title":"IMatch2: Compound identification using retention index for analysis of gas chromatography-mass spectrometry data","volume":"1337","author":"Koo","year":"2014","journal-title":"J. Chromatogr. A"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/22\/7\/3496\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:25:27Z","timestamp":1760361927000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/22\/7\/3496"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,28]]},"references-count":47,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2021,4]]}},"alternative-id":["ijms22073496"],"URL":"https:\/\/doi.org\/10.3390\/ijms22073496","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,28]]}}}