title: Clinical implications of microbial biofilms in chronic rhinosinusitis and orbital cellulitis.
abstract: BACKGROUND
  Discovery of sessile mode of microbial existence (Biofilm state) focussed much interest, during the recent years, on the study of biofilms in many recurring and chronic infections. However, the exact role of microbial biofilms in chronic rhinosinusitis and orbital cellulitis were not elucidated earlier. The purpose of the present study was to look for the adherent property and biofilm producing ability of the clinical isolates in chronic rhinosinusitis and orbital cellulitis, and to look for the effects of antimicrobial agents on these biofilms by colorimetric assay and ultrastructural analysis.
  
  
  METHODS
  Organisms were isolated and identified from various clinical samples in patients with chronic sinusitis and orbital cellulitis. Antimicrobial sensitivity testing was carried out by the standard protocol. Biofilms were developed; quantified and antimicrobial drug perfusion through the biofilm model was evaluated by the earlier devised procedure. Electronmicroscopic study of the biofilm was performed by the recommended technique.
  
  
  RESULTS
  Of the total of 70 clinical samples processed, 48 i.e. 68.5 % grew bacteria and 13 i.e.(18.6 %) fungi. Staphylococcus aureus (20), S epidermidis (16) and Pseudomonas aeruginosa (6) accounted for the majority of the bacterial isolates. Aspergillus flavus (8), however was the commonest amongst the fungi. A total of 40 bacteria and 8 fungi could be tested for biofilm production. Eighteen (45 %) of the 40 bacterial isolates and 4(50 %) out of the 8 A flavus isolates were found to be biofilm producers. In vitro adherence testing revealed that majority i.e. 16 (88.8 %) of the 18 biofilm positive bacteria were adherent to artificial surfaces. Antimicrobial drug perfusion through the biofilm model was poor. Antimicrobial treatment was totally ineffective against strong biofilm producers, whose electron microscopic picture was quite similar to that observed for biofilm producers without any antimicrobial pre-treatment.
  
  
  CONCLUSIONS
  Filamentous fungi, like bacteria were capable of forming biofilms, which could be one of the important virulence factors in determining the pathogenic potential of these organisms in causing chronic rhinosinusitis and orbital cellulitis.
authors.affiliation: Department of Ocular Microbiology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India. niruni2000@yahoo.com.|Department of Microbiology, Manipal College of Medical Sciences, Pokhara, Nepal. niruni2000@yahoo.com.
authors.forename: Niranjan
authors.initials: N
authors.lastname: Nayak
authors.affiliation: Department of Ocular Microbiology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: Gita
authors.initials: G
authors.lastname: Satpathy
authors.affiliation: Department of Ocular Microbiology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: Sujata
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Department of Otorhinolaryngology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: Alok
authors.initials: A
authors.lastname: Thakar
authors.affiliation: Division of Oculopasty, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Chandra
authors.affiliation: Department of Anatomy, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
authors.forename: T C
authors.initials: TC
authors.lastname: Nag
keywords: Amphotericin B; Biofilm; Chronic Rhinosinusitis; Obital Cellulitis