title: Identification of a conserved chromosomal region encoding Klebsiella pneumoniae type 1 and type 3 fimbriae and assessment of the role of fimbriae in pathogenicity.
abstract: Type 3 fimbriae are expressed by most clinical Klebsiella pneumoniae isolates and mediate adhesion to host structures in vitro. However, the role of type 3 fimbriae in K. pneumoniae virulence has not been evaluated by use of in vivo infection models. In this study, the type 3 fimbrial gene cluster (mrk) of the clinical isolate C3091 is described in detail. The mrk gene cluster was revealed to be localized in close proximity to the type 1 fimbrial gene cluster. Thus, a 20.4-kb fimbria-encoding region was identified and found to be highly conserved among different K. pneumoniae isolates. Interestingly, a homologue to PecS, known as a global regulator of virulence in Erwinia chrysanthemi, was identified in the fimbria-encoding region. Comparison to the previously characterized plasmid encoded mrk gene cluster revealed significant differences, and it is established here that the putative regulatory gene mrkE is not a part of the chromosomally encoded type 3 fimbrial gene cluster. To evaluate the role of type 3 fimbriae in virulence, a type 3 fimbria mutant and a type 1 and type 3 fimbria double mutant was constructed. Type 3 fimbria expression was found to strongly promote biofilm formation. However, the fimbria mutants were as effective at colonizing the intestine as the wild type, and their virulence was not attenuated in a lung infection model. Also, in a urinary tract infection model, type 3 fimbriae did not influence the virulence, whereas type 1 fimbriae were verified as an essential virulence factor. Thus, type 3 fimbriae were established not to be a virulence factor in uncomplicated K. pneumoniae infections. However, since type 3 fimbriae promote biofilm formation, their role in development of infections in catheterized patients needs to be elucidated.
authors.affiliation: Department of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Artillerivej 5, 2300S Copenhagen, Denmark. cas@ssi.dk
authors.forename: Carsten
authors.initials: C
authors.lastname: Struve
authors.forename: Martin
authors.initials: M
authors.lastname: Bojer
authors.forename: Karen Angeliki
authors.initials: KA
authors.lastname: Krogfelt
mesh_terms: D000818:Animals; D001483:Base Sequence; D018441:Biofilms; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D036781:Fimbriae Proteins / Q000235:genetics*; D010861:Fimbriae, Bacterial / Q000235:genetics*; D007710:Klebsiella Infections / Q000235:genetics*; D007711:Klebsiella pneumoniae / Q000472:pathogenicity* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D014774:Virulence
chemical_list: D004269:DNA, Bacterial; D036781:Fimbriae Proteins
references.citation: J Bacteriol. 1983 Aug;155(2):860-5
references.pmid: 6135689
references.citation: J Leukoc Biol. 1992 Sep;52(3):343-8
references.pmid: 1355788
references.citation: J Infect Dis. 1988 Feb;157(2):264-71
references.pmid: 2891774
references.citation: Clin Microbiol Rev. 1998 Oct;11(4):589-603
references.pmid: 9767057
references.citation: Infect Immun. 1997 Jul;65(7):2950-8
references.pmid: 9199471
references.citation: J Bacteriol. 1991 Jan;173(2):916-20
references.pmid: 1670938
references.citation: FEBS Lett. 1987 Jun 15;217(2):145-57
references.pmid: 2885220
references.citation: Infect Immun. 1983 Mar;39(3):1122-7
references.pmid: 6132874
references.citation: Infect Immun. 2002 May;70(5):2583-90
references.pmid: 11953399
references.citation: FEMS Microbiol Ecol. 2002 Nov 1;42(2):251-9
references.pmid: 19709285
references.citation: Yale J Biol Med. 1967 Dec;40(3):231-7
references.pmid: 4870557
references.citation: Infect Immun. 1998 Jun;66(6):2887-94
references.pmid: 9596764
references.citation: Microb Pathog. 2000 Aug;29(2):81-91
references.pmid: 10906263
references.citation: Infect Immun. 1995 May;63(5):2026-32
references.pmid: 7729917
references.citation: Infect Immun. 1992 Apr;60(4):1577-88
references.pmid: 1312518
references.citation: Am J Gastroenterol. 2005 Feb;100(2):322-31
references.pmid: 15667489
references.citation: Antimicrob Agents Chemother. 2001 Apr;45(4):1078-85
references.pmid: 11257018
references.citation: Res Microbiol. 2003 Jan-Feb;154(1):9-16
references.pmid: 12576153
references.citation: Microbiology (Reading). 2008 Jan;154(Pt 1):187-195
references.pmid: 18174137
references.citation: Mol Microbiol. 1990 Aug;4(8):1353-61
references.pmid: 1980713
references.citation: Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8922-6
references.pmid: 9671780
references.citation: Curr Opin Microbiol. 2006 Apr;9(2):153-9
references.pmid: 16529980
references.citation: Microbiology (Reading). 2003 Sep;149(Pt 9):2397-2405
references.pmid: 12949165
references.citation: J Bacteriol. 2008 Nov;190(22):7508-22
references.pmid: 18790868
references.citation: Environ Microbiol. 2004 Jun;6(6):584-90
references.pmid: 15142246
references.citation: Infect Immun. 1994 Oct;62(10):4186-91
references.pmid: 7927674
references.citation: Infect Immun. 1996 Sep;64(9):3811-7
references.pmid: 8751933
references.citation: J Med Microbiol. 2004 Jul;53(Pt 7):585-593
references.pmid: 15184527
references.citation: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6640-5
references.pmid: 10829079
references.citation: Rev Infect Dis. 1979 Sep-Oct;1(5):736-53
references.pmid: 396632
references.citation: Microbiology (Reading). 2003 Jan;149(Pt 1):167-76
references.pmid: 12576590
references.citation: Infect Immun. 2008 Sep;76(9):4055-65
references.pmid: 18559432
references.citation: Mol Microbiol. 1994 Mar;11(6):1127-39
references.pmid: 8022282
references.citation: Int J Antimicrob Agents. 2007 Nov;30(5):385-9
references.pmid: 17716872
references.citation: Infect Immun. 1992 Mar;60(3):1187-92
references.pmid: 1347287
references.citation: FEMS Immunol Med Microbiol. 2003 Sep 22;38(2):113-6
references.pmid: 13129645
references.citation: Science. 1998 Nov 20;282(5393):1494-7
references.pmid: 9822381
references.citation: Infect Immun. 1997 Apr;65(4):1546-9
references.pmid: 9119502
references.citation: Emerg Infect Dis. 2002 Feb;8(2):160-6
references.pmid: 11897067
references.citation: Res Microbiol. 2009 Jan-Feb;160(1):71-9
references.pmid: 19028568
references.citation: Infect Immun. 2005 Nov;73(11):7588-96
references.pmid: 16239562
references.citation: Mol Microbiol. 2005 Nov;58(4):1054-73
references.pmid: 16262790
references.citation: Infect Immun. 2001 Sep;69(9):5805-12
references.pmid: 11500458
references.citation: Proc Natl Acad Sci U S A. 1996 Sep 3;93(18):9827-32
references.pmid: 8790416
references.citation: Clin Infect Dis. 1998 Jun;26(6):1434-8
references.pmid: 9636876
references.citation: EMBO J. 2000 Apr 3;19(7):1450-7
references.pmid: 10747013
references.citation: Science. 1997 Apr 25;276(5312):607-11
references.pmid: 9110982
references.citation: Clin Microbiol Rev. 2002 Apr;15(2):167-93
references.pmid: 11932229
references.citation: Antimicrob Agents Chemother. 2000 Jan;44(1):156-63
references.pmid: 10602738
references.citation: Infect Immun. 2004 Mar;72(3):1423-30
references.pmid: 14977947
references.citation: Infect Immun. 2008 Feb;76(2):771-80
references.pmid: 18039830
references.citation: J Gen Microbiol. 1959 Aug;21:271-86
references.pmid: 13818511
references.citation: Int J Med Microbiol. 2000 Mar;290(1):27-35
references.pmid: 11043979
references.citation: J Bacteriol. 2008 Feb;190(3):1054-63
references.pmid: 18055599