Aspergillus fumigatus DBM 4057 biofilm formation is inhibited by chitosan, in contrast to baicalein and rhamnolipid
The biofilms of filamentous-forming fungi are a novel and still insufficiently understood research topic. We have studied Aspergillus fumigatus, an ubiquitous opportunistic pathogenic fungus, as a representative model for a study of biofilm formation by filamentous fungi and for assessing the potential anti-biofilm activity of natural substances. The activity of antibiotic amphotericin B and selected natural substances: baicalein, chitosan and rhamnolipid was studied. The minimum suspension inhibitory concentrations (MIC) were determined and the biofilm susceptibility was investigated by determining the metabolic activity of sessile cells (XTT assay) and total biofilm biomass (crystal violet staining). Significant time-dependent differences in substances’ anti-biofilm activity were observed. Images of A. fumigatus biofilm were obtained by Cellavista automatic light microscope and spinning disc confocal microscopy. Baicalein and rhamnolipid were not found as suitable substances for inhibition of the A. fumigatus biofilm formation, as neither of the substances inhibited the sessile cells metabolic activity or the total biofilm biomass even at tenfold MIC after 48 h. In contrast, chitosan at 10 × MIC (25 µg mL−1), suppressed the biofilm metabolic activity by 90 % and the total biofilm biomass by 80 % even after 72 h of cultivation. Amphotericin B inhibited only 14 % of total biofilm biomass (crystal violet staining) and 35 % of metabolic activity (XTT assay) of adherent cells under the same conditions. Our results therefore suggest chitosan as potential alternative for treating A. fumigatus biofilm-associated infections.
KeywordsAmphotericin B Aspergillus fumigatus Biofilm Chitosan Rhamnolipid
This work was supported by the Czech Science Foundation (GA CR) [14-23597S].
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bugli F, Posteraro B, Papi M, Torelli R, Maiorana A, Paroni Sterbini F, Posteraro P, Sanguinetti M, De Spirito M (2013) In vitro interaction between alginate lyase and amphotericin B against Aspergillus fumigatus biofilm determined by different methods. Antimicrob Agents Chemother 57:1275–1282CrossRefGoogle Scholar
- Dai BD, Cao YY, Huang S, Xu YG, Gao PH, Wang Y, Jiang YY (2009) Baicalein induces programmed cell death in Candida albicans. J Microbiol Biotechn 19:803–809Google Scholar
- Fanfair RN, Benedict K, Bos J, Bennett SD, Lo YC, Adebanjo T, Etienne K, Deak E, Derado G, Shieh WJ, Drew C, Zaki S, Sugerman D, Gade L, Thompson EH, Sutton DA, Engelthaler DM, Schupp JM, Brandt ME, Harris JR, Lockhart SR, Turabelidze G, Park BJ (2012) Necrotizing cutaneous mucormycosis after a tornado in Joplin, Missouri, in 2011. N Engl J Med 367:2214–2225CrossRefGoogle Scholar
- Hoskova M, Jezdik R, Schreiberova O, Chudoba J, Sir M, Cejkova A, Masak J, Jirku V, Rezanka T (2015) Structural and physiochemical characterization of rhamnolipids produced by Acinetobacter calcoaceticus, Enterobacter asburiae and Pseudomonas aeruginosa in single strain and mixed cultures. J Biotechnol 193:45–51CrossRefGoogle Scholar
- Kaur S, Singh S (2014) Biofilm formation by Aspergillus fumigatus. Med Mycol 52:2–9Google Scholar
- Latge JP (1999) Aspergillus fumigatus and aspergillosis. Clin Microbiol Rev 12:310–350Google Scholar
- Park Y, Kim M-H, Park S-C, Cheong H, Jang M-K, Nah J-W, Hahm K-S (2008) Investigation of the antifungal activity and mechanism of action of LMWS-chitosan. J Microbiol Biotechnol 18:1729–1734Google Scholar
- Rezanka T, Kolouchova I, Cejkova A, Sigler K (2012) Natural products: Strategic tools for modulation of biofilm formation. In: Atta-ur-Rahman F (ed) Studies in natural products chemistry, vol 38. Elsevier, Amsterdam, pp 269–303Google Scholar
- Silva WJd, Seneviratne J, Parahitiyawa N, Rosa EAR, Samaranayake LP, Cury AADB (2008) Improvement of XTT assay performance for studies involving Candida albicans biofilms. Braz Dent J 19:364–369Google Scholar
- Warkentien T, Rodriguez C, Lloyd B, Wells J, Weintrob A, Dunne JR, Ganesan A, Li P, Bradley W, Gaskins LJ, Seillier-Moiseiwitsch F, Murray CK, Millar EV, Keenan B, Paolino K, Fleming M, Hospenthal DR, Wortmann GW, Landrum ML, Kortepeter MG, Tribble DR (2012) Invasive mold infections following combat-related Injuries. Clin Infect Dis 55:1441–1449CrossRefGoogle Scholar