title: Fungal β-1,3-glucan increases ofloxacin tolerance of Escherichia coli in a polymicrobial E. coli/Candida albicans biofilm.
abstract: In the past, biofilm-related research has focused mainly on axenic biofilms. However, in nature, biofilms are often composed of multiple species, and the resulting polymicrobial interactions influence industrially and clinically relevant outcomes such as performance and drug resistance. In this study, we show that Escherichia coli does not affect Candida albicans tolerance to amphotericin or caspofungin in an E. coli/C. albicans biofilm. In contrast, ofloxacin tolerance of E. coli is significantly increased in a polymicrobial E. coli/C. albicans biofilm compared to its tolerance in an axenic E. coli biofilm. The increased ofloxacin tolerance of E. coli is mainly biofilm specific, as ofloxacin tolerance of E. coli is less pronounced in polymicrobial E. coli/C. albicans planktonic cultures. Moreover, we found that ofloxacin tolerance of E. coli decreased significantly when E. coli/C. albicans biofilms were treated with matrix-degrading enzymes such as the β-1,3-glucan-degrading enzyme lyticase. In line with a role for β-1,3-glucan in mediating ofloxacin tolerance of E. coli in a biofilm, we found that ofloxacin tolerance of E. coli increased even more in E. coli/C. albicans biofilms consisting of a high-β-1,3-glucan-producing C. albicans mutant. In addition, exogenous addition of laminarin, a polysaccharide composed mainly of poly-β-1,3-glucan, to an E. coli biofilm also resulted in increased ofloxacin tolerance. All these data indicate that β-1,3-glucan from C. albicans increases ofloxacin tolerance of E. coli in an E. coli/C. albicans biofilm.
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Katrijn
authors.initials: K
authors.lastname: De Brucker
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Katlijn
authors.initials: K
authors.lastname: Vints
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium Department of Plant Systems Biology, VIB, Ghent, Belgium.
authors.forename: Kaat
authors.initials: K
authors.lastname: De Cremer
authors.affiliation: Department of Materials Engineering, MTM, KU Leuven, Leuven, Belgium.
authors.forename: Annabel
authors.initials: A
authors.lastname: Braem
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Natalie
authors.initials: N
authors.lastname: Verstraeten
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Michiels
authors.affiliation: Department of Materials Engineering, MTM, KU Leuven, Leuven, Belgium.
authors.forename: Jef
authors.initials: J
authors.lastname: Vleugels
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium Department of Plant Systems Biology, VIB, Ghent, Belgium bruno.cammue@biw.kuleuven.be.
authors.forename: Bruno P A
authors.initials: BP
authors.lastname: Cammue
authors.affiliation: Centre of Microbial and Plant Genetics, CMPG, KU Leuven, Leuven, Belgium.
authors.forename: Karin
authors.initials: K
authors.lastname: Thevissen
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D025141:Drug Resistance, Fungal; D004926:Escherichia coli / Q000187:drug effects* / Q000648:ultrastructure; D015242:Ofloxacin / Q000494:pharmacology*; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D047071:beta-Glucans; C033363:beta-1,3-glucan; D015242:Ofloxacin