What are Biofilms?:  Bacteria, fungi and yeast exists in two forms: (1) fee floating organisms called planktonic forms and 2) sessile forms known as biofilms.   The biofilms are an adaptive phenotypic  switch that occurs in bacteria, fungi and yeast. Biofilms are the main mode of survival and proliferation of  these micro organisms. The biofilm  isan extracellular matrix ECM) consisting of polysaccharides, nucleic acids, proteins and extra-cellular DNA (Tamashiro et al, 2009; Loussert et al, 2010; Nailis et al, 2010).  The biofilm is 90 % water and 10 % ECM and cells.  The ECM is porous allowing nutrients to penetrate the biofilm and to permits waste excretion.  Ironically, the biofilm protects the cells within the ECM from shear-gradients, antibiotics, antifungals, and the innate and adaptive host defenses. Treatment of chronic fungal and bacterial rhinosinusitis with antifungals and/or antibiotics kills off the planktonic organisms while leaving the biofilm organisms essentially untouched.  Thus, chronic flare-ups of the sinusitis recur (Tamashiro et al, 2009; Mowat et al, 2008;Singhal et al, 2010).

The frequency of biofilms in chronic fungal and bacterial sinusitis patients ranges from 50 to 90 %, depending on the diagnostic protocol (Foreman et al 2009, 2010).  The organisms most often associated with chronic rhinosinusitis are Staphylococcus aureus; Haemophilus influenzae, Pseudomonas aeruginosa, and a variety of fungi including Aspergillus fumigatus (Foreman, Wormald PJ 2010; Chakrabarti et al, 2009).  However a variety of aerobic and anaerobic bacteria have also been reported (Brook, 2006).

Current efforts are being directed towards the efficacy of various treatments to penetrate and beak down the biofilms.  So far, N-acetylcystein has been shown to break down the adhesion properties of biofilms (Pintucci et al 2010).  While in a sheep model regular treatment with mupicron produced a marked reduction in the biofilm surface area (Le et al, 2010).  It is apparent that a concerted effort is needed to reduce recurrent exacerbations that are associated with biofilm protection of infectious agents.


References:  Click on references below to obtain copies of the papers cited.  If you wish to have copies of the papers cited as abstract, please email me.

Brook I. 2006. Bacteriology of chronic sinusitis. Arch Otolaryngol 132:1099-1101.

Chakrabarti A, Denning DW, Ferguson BJ, Ponikau J, etg al. Rungal rhinosinusitis: A categorization and definitional schema addressing current controversies. Laryngoscope 119:1809-18.

Foreman A, Psaltis A, Tan LW, Wormald PJ. 2009. Characterization of bacterial and fungal biofilms in chronic rhinosinusitis. Am J Rhinol Allergy 23:556-61.

Foreman A, Singhal D, Psaltis AJ, Wormald PJ. 2010. Targeted imaging modality selection for bacterial biofilm in chronic rhinosinusitis. Laryngoscope 120:247-31.

Foreman A, Wormald PJ. 2010. Different biofilms, different disease? A clincal outcomes study. Laryngoscope 120:1701-6.

Le &, Psaltis A, Tan LW, Wormald PJ. 2008, The efficacy of topical antibiofilm agents in a sheep model of rhinosinustis. Am J Rhinol 22:560-7.

Loussert C, Schmitt C, Prevost MC, Balloy V, et al. 2010. In vivo biofilm composition of Aspergillus fumigatus. Cellullar Microbiol 12:405-410.

Mowat E, Lang S, Williams C, McCulloch E, et al. 2008. Phase-dependent antifungal activity against Aspergillus fumigatus developing in multicellular filamentous biofilms. J Antimicrob Chermotherap 62:1281-4.

Nailis H, Kurcharikova S, Ricicova M, Van Dijck P, et al. 2010. Real-time PCR expression profiling genes encoding potential virulence factors in Candida albicans biofilm: identification of model-dependent and -independent gene expression. BMC Microbiol 10:214.

Pintucci JP, Corno S, Garotta M.  2010. Biofilms and infections of the upper resiratory tract. Eur Rev Med Pharmacol Sci. 24:683-90.

Singhal D, Psaltis AJ, Forman A, Womald PJ. 2010. The impact of biofilms after endoscopic sinus surgery. Am J Rhinol Allerg 24:169-74.

Tamashiro E, Antunes MB, Palmer JN, Coen NA, et al. 2009. Implications of chronic rhinosinusitis. Braz  J Infect Dis 13:232-35.