Biofilms and chronic otitis media: an initial exploration into the role of biofilms in the pathogenesis of chronic otitis media

Hoa, Michael; Md, Mausumi N Syamal; Schaeffer, Michele A; Sachdeva, Livjot; Berk, Richard S.; Coticchia, James M.

doi:10.1016/j.amjoto.2009.02.015

Cited by 51 publications

(36 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Progression to other sites of the human body results in disease. Like many other bacterial pathogens, pneumococcal colonization and disease often is associated with biofilm formation (13,22). Biofilm formation is a complex and multifactorial process that involves several steps.…”

mentioning

confidence: 99%

LuxS Mediates Iron-Dependent Biofilm Formation, Competence, and Fratricide in Streptococcus pneumoniae

et al. 2011

View full text Add to dashboard Cite

During infection, Streptococcus pneumoniae exists mainly in sessile biofilms rather than in planktonic form, except during sepsis. The capacity to form biofilms is believed to be important for nasopharyngeal colonization as well as disease pathogenesis, but relatively little is known about the regulation of this process. Here, we investigated the effect of exogenous iron [Fe(III)] as well as the role of luxS (encoding S-ribosylhomocysteine lyase) on biofilm formation by S. pneumoniae D39. Fe(III) strongly enhanced biofilm formation at concentrations of >50 M, while Fe(III) chelation with deferoxamine was inhibitory. Importantly, Fe(III) also upregulated the expression of luxS in wild-type D39. A luxS-deficient mutant (D39luxS) failed to form a biofilm, even with Fe(III) supplementation, whereas a derivative overexpressing luxS (D39luxS؉) exhibited enhanced biofilm formation capacity and could form a biofilm without added Fe(III). D39luxS exhibited reduced expression of the major Fe(III) transporter PiuA, and the cellular [Fe(III)] was significantly lower than that in D39; in contrast, D39luxS؉ had a significantly higher cellular [Fe(III)] than the wild type. The release of extracellular DNA, which is an important component of the biofilm matrix, also was directly related to luxS expression. Similarly, genetic competence, as measured by transformation frequency as well as the expression of competence genes comD, comX, comW, cglA, and dltA and the murein hydrolase cbpD, which is associated with fratricide-dependent DNA release, all were directly related to luxS expression levels and were further upregulated by Fe(III). Moreover, mutagenesis of cbpD blocked biofilm formation. We propose that competence, fratricide, and biofilm formation are closely linked in pneumococci, and that luxS is a central regulator of these processes. We also propose that the stimulatory effects of Fe(III) on all of these parameters are due to the upregulation of luxS expression, and that LuxS provides for a positive Fe(III)-dependent amplification loop by increasing iron uptake.

show abstract

mentioning

confidence: 99%

LuxS Mediates Iron-Dependent Biofilm Formation, Competence, and Fratricide in Streptococcus pneumoniae

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Adenotonsillar hypertrophy and chronic tonsillitis have been associated with high prevalence of biofilms on the tonsils and adenoids [20,21]). Biofilms have also been demonstrated in adenoid tissue as well as middle ear samples of patients with ROM and COM [22,23]. This raises the question of whether these disease processes may be related, possibly at the level of defense against biofilm formation.…”

Section: Discussionmentioning

confidence: 99%

Innate immunity gene single nucleotide polymorphisms and otitis media

Carroll

Zald

Soler

et al. 2012

International Journal of Pediatric Otorhinolaryngology

View full text Add to dashboard Cite

“…To study the effect of 5-aza on S. pneumoniae biofilm formation at different time intervals, we performed pneumococcal biofilm formation with 100 mM 5-aza at different time intervals (6,12,18 and 24 h). The biofilms grown in medium devoid of 5-aza was the negative control.…”

Section: In Vitro Biofilm Formationmentioning

confidence: 99%

Effect of 5-azacytidine on in vitro biofilm formation of Streptococcus pneumoniae

Yadav

Chae

Song

2012

Microbial Pathogenesis

View full text Add to dashboard Cite

Biofilms and chronic otitis media: an initial exploration into the role of biofilms in the pathogenesis of chronic otitis media

Cited by 51 publications

References 27 publications

LuxS Mediates Iron-Dependent Biofilm Formation, Competence, and Fratricide in Streptococcus pneumoniae

LuxS Mediates Iron-Dependent Biofilm Formation, Competence, and Fratricide in Streptococcus pneumoniae

Innate immunity gene single nucleotide polymorphisms and otitis media

Effect of 5-azacytidine on in vitro biofilm formation of Streptococcus pneumoniae

Contact Info

Product

Resources

About