Open AccessEvidence of the presence of nucleic acids and β-glucan in the matrix of non-typeable Haemophilus influenzae in vitro biofilms
Author(s) -
Mirian Domenech,
Elena Pedrero-Vega,
Alicia Prieto,
Ernesto Garcı́a
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep36424
Subject(s) - biofilm , microbiology and biotechnology , haemophilus influenzae , nucleic acid , in vitro , bacteria , extracellular matrix , biology , chemistry , biochemistry , antibiotics , genetics
Non-typeable Haemophilus influenzae (NT Hi ) is a Gram-negative bacterium that frequently colonizes the human nasopharynx; it is a common cause of chronic and recurrent otitis media in children and of exacerbations of chronic obstructive pulmonary disease. To date, no exopolysaccharide clearly contributing to NT Hi biofilms has been identified. Consequently, there is some debate as to whether NT Hi forms biofilms during colonization and infection. The present work shows that NT Hi can form biofilms in vitro, producing an extracellular matrix composed of proteins, nucleic acids, and a β-glucan. Extracellular DNA, visualized by immunostaining and using fluorochromes, is an important component of this matrix and appears to be essential in biofilm maintenance. Extracellular RNA appears to be required only in the first steps of biofilm formation. Evidence of a matrix polysaccharide was obtained by staining with Calcofluor white M2R and by disaggregating biofilms with cellulase. Using strain 54997, residues of Glc p (1→4) in the NT Hi biofilm were confirmed by gas-liquid chromatography-mass spectrometry. Evidence that N -acetyl-L-cysteine shows notable killing activity towards in vitro NT Hi biofilm-forming bacteria is also provided.