Identification and characterization of an Acinetobacter baumannii biofilm-associated protein

Thomas W Loehfelm, Nicole R. Luke, Anthony A. Campagnari

Research output: Contribution to journalArticle

144 Scopus citations

Abstract

We have identified a homologue to the staphylococcal biofilm-associated protein (Bap) in a bloodstream isolate of Acinetobacter baumannii. The fully sequenced open reading frame is 25,863 bp and encodes a protein with a predicted molecular mass of 854 kDa. Analysis of the nucleotide sequence reveals a repetitive structure consistent with bacterial cell surface adhesins. Bap-specific monoclonal antibody (MAb) 6E3 was generated to an epitope conserved among 41% of A. baumannii strains isolated during a recent outbreak in the U.S. military health care system. Flow cytometry confirms that the MAb 6E3 epitope is surface exposed. Random transposon mutagenesis was used to generate A. baumannii bap1302::EZ-Tn5, a mutant negative for surface reactivity to MAb 6E3 in which the transposon disrupts the coding sequence of bap. Time course confocal laser scanning microscopy and three-dimensional image analysis of actively growing biofilms demonstrates that this mutant is unable to sustain biofilm thickness and volume, suggesting a role for Bap in supporting the development of the mature biofilm structure. This is the first identification of a specific cell surface protein directly involved in biofilm formation by A. baumannii and suggests that Bap is involved in intercellular adhesion within the mature biofilm.

Original languageEnglish (US)
Pages (from-to)1036-1044
Number of pages9
JournalJournal of Bacteriology
Volume190
Issue number3
DOIs
StatePublished - Feb 2008
Externally publishedYes

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

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