Identification of a conserved chromosomal region encoding Klebsiella pneumoniae type 1 and type 3 fimbriae and assessment of the role of fimbriae in pathogenicity.
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.
Struve
Carsten
C
Department of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Artillerivej 5, 2300S Copenhagen, Denmark. cas@ssi.dk
Bojer
Martin
M
Krogfelt
Karen Angeliki
KA
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
D004269:DNA, Bacterial; D036781:Fimbriae Proteins
J Bacteriol. 1983 Aug;155(2):860-5
6135689
J Leukoc Biol. 1992 Sep;52(3):343-8
1355788
J Infect Dis. 1988 Feb;157(2):264-71
2891774
Clin Microbiol Rev. 1998 Oct;11(4):589-603
9767057
Infect Immun. 1997 Jul;65(7):2950-8
9199471
J Bacteriol. 1991 Jan;173(2):916-20
1670938
FEBS Lett. 1987 Jun 15;217(2):145-57
2885220
Infect Immun. 1983 Mar;39(3):1122-7
6132874
Infect Immun. 2002 May;70(5):2583-90
11953399
FEMS Microbiol Ecol. 2002 Nov 1;42(2):251-9
19709285
Yale J Biol Med. 1967 Dec;40(3):231-7
4870557
Infect Immun. 1998 Jun;66(6):2887-94
9596764
Microb Pathog. 2000 Aug;29(2):81-91
10906263
Infect Immun. 1995 May;63(5):2026-32
7729917
Infect Immun. 1992 Apr;60(4):1577-88
1312518
Am J Gastroenterol. 2005 Feb;100(2):322-31
15667489
Antimicrob Agents Chemother. 2001 Apr;45(4):1078-85
11257018
Res Microbiol. 2003 Jan-Feb;154(1):9-16
12576153
Microbiology (Reading). 2008 Jan;154(Pt 1):187-195
18174137
Mol Microbiol. 1990 Aug;4(8):1353-61
1980713
Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8922-6
9671780
Curr Opin Microbiol. 2006 Apr;9(2):153-9
16529980
Microbiology (Reading). 2003 Sep;149(Pt 9):2397-2405
12949165
J Bacteriol. 2008 Nov;190(22):7508-22
18790868
Environ Microbiol. 2004 Jun;6(6):584-90
15142246
Infect Immun. 1994 Oct;62(10):4186-91
7927674
Infect Immun. 1996 Sep;64(9):3811-7
8751933
J Med Microbiol. 2004 Jul;53(Pt 7):585-593
15184527
Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6640-5
10829079
Rev Infect Dis. 1979 Sep-Oct;1(5):736-53
396632
Microbiology (Reading). 2003 Jan;149(Pt 1):167-76
12576590
Infect Immun. 2008 Sep;76(9):4055-65
18559432
Mol Microbiol. 1994 Mar;11(6):1127-39
8022282
Int J Antimicrob Agents. 2007 Nov;30(5):385-9
17716872
Infect Immun. 1992 Mar;60(3):1187-92
1347287
FEMS Immunol Med Microbiol. 2003 Sep 22;38(2):113-6
13129645
Science. 1998 Nov 20;282(5393):1494-7
9822381
Infect Immun. 1997 Apr;65(4):1546-9
9119502
Emerg Infect Dis. 2002 Feb;8(2):160-6
11897067
Res Microbiol. 2009 Jan-Feb;160(1):71-9
19028568
Infect Immun. 2005 Nov;73(11):7588-96
16239562
Mol Microbiol. 2005 Nov;58(4):1054-73
16262790
Infect Immun. 2001 Sep;69(9):5805-12
11500458
Proc Natl Acad Sci U S A. 1996 Sep 3;93(18):9827-32
8790416
Clin Infect Dis. 1998 Jun;26(6):1434-8
9636876
EMBO J. 2000 Apr 3;19(7):1450-7
10747013
Science. 1997 Apr 25;276(5312):607-11
9110982
Clin Microbiol Rev. 2002 Apr;15(2):167-93
11932229
Antimicrob Agents Chemother. 2000 Jan;44(1):156-63
10602738
Infect Immun. 2004 Mar;72(3):1423-30
14977947
Infect Immun. 2008 Feb;76(2):771-80
18039830
J Gen Microbiol. 1959 Aug;21:271-86
13818511
Int J Med Microbiol. 2000 Mar;290(1):27-35
11043979
J Bacteriol. 2008 Feb;190(3):1054-63
18055599