Abstract

SUESCUN, Ana Victoria; CUBILLOS, Juan Rodrigo  and  ZAMBRANO, María Mercedes. Genes involved in fimbrial biogenesis affect biofilm formation in Klebsiella pneumoniae. Biomédica [online]. 2006, vol.26, n.4, pp.528-537. ISSN 0120-4157.

Introduction. Klebsiella pneumoniae is an opportunistic pathogen commonly associated with nosocomial infections. The persistence and pathogenesis of this microorganism is associated with its capacity to form biofilms. Pili or fimbriae are among the factors implicated in biofilm formation in diverse microorganisms. Klebsiella pneumoniae expresses both type 1 and type 3 fimbriae-proteinacious structures that mediate adhesion to epithelial cells and are important for virulence. To identify genes involved in biofilm formation in K. pneumoniae. Klebsiella pneumoniae MZ2098 was subjected to mutagenesis with the miniTn10Km transposon and screened for defects in ability to form biofilms. The bacteria were curltured in 96-well plates using BHI-MOPS medium. Selected mutants were analyzed under diverse conditions by varying culture conditions and growth surfaces. Genes interrupted by the transposon were identified by arbitrary polymerase chain reaction and sequencing. Thirty-seven mutants deficient in biofilm formation were obtained by screening 9,300 transposon-insertion mutants in K. pneumoniae. Three of these mutants had insertions in genes that affected fimbrial formation, and their phenotypes showed severe defects in the capacity to adhere to surfaces in vitro. Type 1 and type 3 fimbriae are important factors for adhesion and formation of multicellular aggregates of K. pneumoniae.

Keywords : Klebsiella pneumoniae; opportunistic infections; biofilms; bacterial fimbriae; bacterial adhesion; microbial genetics.

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