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BioMed Research International
Volume 2013 (2013), Article ID 690217, 7 pages
Research Article

Hyaluronic Acid Derived from Other Streptococci Supports Streptococcus pneumoniae In Vitro Biofilm Formation

1Department of Otorhinolaryngology-Head and Neck Surgery, Dongguk University Ilsan Hospital, Goyang, Gyeonggi 410-773, Republic of Korea
2Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul 135-705, Republic of Korea
3Chuncheon Center, Korea Basic Science Institute, 192-1 Hyoja 2-dong, Chuncheon, Gangwon-do 200-701, Republic of Korea

Received 16 April 2013; Revised 8 August 2013; Accepted 21 August 2013

Academic Editor: H. C. Van der Mei

Copyright © 2013 Mukesh Kumar Yadav et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We investigate the role of hyaluronic acid (HA) on S. pneumoniae in vitro biofilm formation and evaluate gene expressions of virulence and/or biofilm related genes. Biofilms were grown in medium supplied with HA derived from capsule of Streptococcus equi. The biomasses of biofilms were detected by crystal-violet (CV) microtiter plate assay, and the morphology was viewed under scanning electron microscope (SEM). The gene expressions were assessed by relative quantitative RT-PCR. The results showed that the HA support pneumococcal growth in planktonic form and within biofilms. The CV-microtiter plate assay detected significantly increased biofilm growth in medium containing HA. The SEM analysis revealed thick and organized biofilms in positive control and HA supplemented medium. The nanA, nanB, bgaA, strH, luxS, hysA, ugl, and PST-EIIA encoding genes were significantly upregulated in the planktonic cells grown in presence of HA, while the lytA and comA genes were downregulated. Similarly the luxS, hysA, ugl, and PST-EIIA encoding genes were significantly upregulated by more than 2-folds in HA biofilms. The results of this study indicate that the HA derived from capsule of S. equi supports pneumococcal growth in planktonic state and within biofilms and upregulated virulence and biofilm related genes.