HEAD AND NECK Determination of the biofilm formation capacity of bacterial pathogens associated with otorhinolaryngologic diseases in the Malaysian population Yalda Khosravi • Lina Chooi Ling • Mun Fai Loke • Sivalingam Shailendra • Narayanan Prepageran • Jamuna Vadivelu Received: 7 June 2013 / Accepted: 9 July 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract This study aims to assess the association between microbial composition, biofilm formation and chronic otorhinolaryngologic disorders in Malaysia. A total of 45 patients with chronic rhinosinusitis, chronic tonsillitis and chronic suppurative otitis media and 15 asymptomatic control patients were studied. Swab samples were obtained from these subjects. Samples were studied by conventional microbiological culturing, PCR-based microbial detection and Confocal Laser Scanning Microscopy (CLSM). Hae- mophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae, coagulase-negative staphylococci (CoNS) and other Streptococcus species were detected in subjects of both patient and control groups. Biofilm was observed in approximately half of the smear prepared from swab samples obtained from subjects of the patient group. Most of these were polymicrobial biofilms. S. aureus biofilm was most prevalent among nasal samples while H. influenzae biofilm was more common among ear and throat samples. Results from this study supported the hypothesis that chronic otorhinolaryngologic diseases may be biofilm related. Due to the presence of unculturable bacteria in biofilms present in specimens from ear, nose and throat, the use of molecular methods in combination with conventional microbiological culturing has demonstrated an improvement in the detection of bacteria from such specimens in this study. Keywords Biofilm  Bacteria  Otorhinolaryngologic diseases Introduction Biofilms are defined as an organized community of bacteria attached to a surface and contained in an extracellular polymeric substance (EPS) composed of exopolysaccha- rides, nucleic acids, proteins, lipids, uronic acid, humic substances and others [1, 2]. The composition may be the result of active secretion, shedding of cell surface material, cell lysis, and adsorption from the environment [2]. Biofilm formation confers bacteria with the ability to resist host immune mechanisms. The exopolysaccharide matrix pro- tects the bacterial cells from phagocytic macrophages and the reduced metabolic rate renders the bacteria less sus- ceptible to antibiotics that attack actively dividing cells [3, 4]. These local conditions encourage persistence of bacteria for periods of months to years, with intermittent occurrence of acute exacerbations. It is worth mentioned that the quorum sensing system plays an essential role in biofilm formation as it was utilized by these biofilm-forming bac- teria to communicate with each other, as well as to deter- mine population density and colonization capacities [5]. The role of biofilms in the persistence of chronic, mucosal-based ENT-related infections was first docu- mented in otitis media [4]. Bacterial biofilms were dis- covered in the middle-ear mucosa of children [6]. However, these bacterial biofilms are not only found in otitis media but also in chronic otitis media with effusion Y. Khosravi, L. C. Ling and M. F. Loke contributed equally to this work. Y. Khosravi  M. F. Loke  J. Vadivelu (&) Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia e-mail: jamuna@ummc.edu.my Y. Khosravi e-mail: yalda_kh22@yahoo.com L. C. Ling  S. Shailendra  N. Prepageran Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia 123 Eur Arch Otorhinolaryngol DOI 10.1007/s00405-013-2637-3