scholarly journals Role of type 1 and type 3 fimbriae in Klebsiella pneumoniae biofilm formation

2010 ◽  
Vol 10 (1) ◽  
pp. 179 ◽  
Author(s):  
Casper Schroll ◽  
Kim B Barken ◽  
Karen A Krogfelt ◽  
Carsten Struve
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Type 3

scholarly journals Identification of a Conserved Chromosomal Region Encoding Klebsiella pneumoniae Type 1 and Type 3 Fimbriae and Assessment of the Role of Fimbriae in Pathogenicity

2009 ◽  
Vol 77 (11) ◽  
pp. 5016-5024 ◽  
Author(s):  
Carsten Struve ◽  
Martin Bojer ◽  
Karen Angeliki Krogfelt
Keyword(s):  
Klebsiella Pneumoniae ◽  
Gene Cluster ◽  
Virulence Factor ◽  
Biofilm Formation ◽  
Regulatory Gene ◽  
Infection Model ◽  
Type 3

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.

scholarly journals Role of Klebsiella pneumoniae Type 1 and Type 3 Fimbriae in Colonizing Silicone Tubes Implanted into the Bladders of Mice as a Model of Catheter-Associated Urinary Tract Infections

2013 ◽  
Vol 81 (8) ◽  
pp. 3009-3017 ◽  
Author(s):  
Caitlin N. Murphy ◽  
Martin S. Mortensen ◽  
Karen A. Krogfelt ◽  
Steven Clegg
Keyword(s):  
Urinary Tract ◽  
Klebsiella Pneumoniae ◽  
Urinary Tract Infections ◽  
Wild Type ◽  
Content Type ◽  
Tract Infections ◽  
Type 3

ABSTRACTCatheter-associated urinary tract infections are biofilm-mediated infections that cause a significant economic and health burden in nosocomial environments. Using a newly developed murine model of this type of infection, we investigated the role of fimbriae in implant-associated urinary tract infections by the Gram-negative bacteriumKlebsiella pneumoniae, which is a proficient biofilm former and a commonly isolated nosocomial pathogen. Studies have shown that type 1 and type 3 fimbriae are involved in attachment and biofilm formationin vitro, and these fimbrial types are suspected to be important virulence factors during infection. To test this hypothesis, the virulence of fimbrial mutants was assessed in independent challenges in which mouse bladders were inoculated with the wild type or a fimbrial mutant and in coinfection studies in which the wild type and fimbrial mutants were inoculated together to assess the results of a direct competition in the urinary tract. Using these experiments, we were able to show that both fimbrial types serve to enhance colonization and persistence. Additionally, a double mutant had an additive colonization defect under some conditions, indicating that both fimbrial types have unique roles in the attachment and persistence in the bladder and on the implant itself. All of these mutants were outcompeted by the wild type in coinfection experiments. Using these methods, we are able to show that type 1 and type 3 fimbriae are important colonization factors in the murine urinary tract when an implanted silicone tube is present.

scholarly journals Role of MrkJ, a Phosphodiesterase, in Type 3 Fimbrial Expression and Biofilm Formation in Klebsiella pneumoniae

2010 ◽  
Vol 192 (15) ◽  
pp. 3944-3950 ◽  
Author(s):  
Jeremiah G. Johnson ◽  
Steven Clegg
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Surface Expression ◽  
Reverse Transcription Pcr ◽  
Genes Encoding ◽  
Bacterial Genes ◽  
Type 3

ABSTRACT Klebsiella pneumoniae is an opportunistic pathogen that has been shown to adhere to human extracellular matrices using the type 3 fimbriae. Introduction of plasmids carrying genes known to alter intracellular cyclic-di-GMP pools in Vibrio parahaemolyticus revealed that these genes also altered type 3 fimbrial surface expression in K. pneumoniae. Immediately adjacent to the type 3 fimbrial gene cluster is a gene, mrkJ, that is related to a family of bacterial genes encoding phosphodiesterases. We identify here a role for MrkJ, a functional phosphodiesterase exhibiting homology to EAL domain-containing proteins, in controlling type 3 fimbria production and biofilm formation in K. pneumoniae. Deletion of mrkJ resulted in an increase in type 3 fimbria production and biofilm formation as a result of the accumulation of intracellular cyclic-di-GMP. This gene was shown to encode a functional phosphodiesterase via restoration of motility in a V. parahaemolyticus strain previously shown to accumulate cyclic-di-GMP and in vitro using phosphodiesterase activity assays. The effect of the mrkJ mutation on type 3 fimbrial expression was shown to be at the level of mrkA gene transcription by using quantitative reverse transcription-PCR. These results reveal a previously unknown role for cyclic-di-GMP in type 3 fimbrial production.

The role of pgaC in Klebsiella pneumoniae virulence and biofilm formation

2014 ◽  
Vol 77 ◽  
pp. 89-99 ◽  
Author(s):  
Kuang-Ming Chen ◽  
Ming-Ko Chiang ◽  
Meilin Wang ◽  
Han-Chen Ho ◽  
Min-Chi Lu ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation

Effects of Antibiotic, Nicotine and Aminoacid starvation stresses on biofilm production in respiratory Klebsiella pneumoniae

2021 ◽  
Vol 30 (1) ◽  
pp. 61-69
Author(s):  
Rochell Davis and Paul D. Brown
Keyword(s):  
Amino Acid ◽  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Genetic Relatedness ◽  
Amino Acid Starvation ◽  
Biofilm Production ◽  
Mar Index ◽  
Type 3 ◽  
Hospital Acquired

Background: Klebsiella pneumoniae is a major cause of hospital-acquired infections in Jamaica. Objective: We aimed to determine their antimicrobial resistance profiles and to assess biofilm formation in the presence of antibiotic, nicotine and amino acid starvation stresses. Methodology: Antimicrobial susceptibility and multiple antimicrobial resistance (MAR) index were determined for 23 K. pneumoniae strains. Biofilm production was evaluated in the presence of 50 μg/ml ceftazidime or gentamicin, 0–4 mg/ml nicotine, or 0.5 mg/ml serine hydroxamate (to induce amino acid starvation). Genetic relatedness, and the presence of type 3 fimbriae (mrkA) and determinants for extended spectrum β-lactamase and carbapenamases (bla-IMP, bla-VIM, bla-GIM and bla-SIM) were assessed by PCR-based amplification. Results: All strains were susceptible to imipenem (p<0.05); frequencies of resistance varied from 4% (for amikacin) and 8.7% (for meropenem) to over 30% for the other antimicrobials. About half of strains were resistant to ceftazidime, gentamicin and piperacillin. Mean MAR index was 0.31. The presence of antibiotics and nicotine at 2 and 4 mg/ml negatively affected biofilm formation for most strains. However, with amino acid starvation, almost 60% of strains retained medium or high biofilm production. Most strains harboured determinants for carbapenemase or metallo--lactamase, and one-third were PCRpositive for the OXA-1 gene. Strains were clustered into three groups based on ERICPCR analysis. Conclusion: These data suggest that certain antibiotics could inhibit biofilm production in K. pneumoniae even as multidrug resistance in this organism is evident. Further, this species has the propensity to harbour several genetic determinants for antimicrobial resistance.

scholarly journals Signature-Tagged Mutagenesis of Klebsiella pneumoniae To Identify Genes That Influence Biofilm Formation on Extracellular Matrix Material

2006 ◽  
Vol 74 (8) ◽  
pp. 4590-4597 ◽  
Author(s):  
Jennifer D. Boddicker ◽  
Rebecca A. Anderson ◽  
Jennifer Jagnow ◽  
Steven Clegg
Keyword(s):  
Extracellular Matrix ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Matrix Material ◽  
Infection Process ◽  
Bladder Epithelium ◽  
Tract Infections ◽  
Type 3

ABSTRACT Klebsiella pneumoniae causes urinary tract infections, respiratory tract infections, and septicemia in susceptible individuals. Strains of Klebsiella frequently produce extended-spectrum beta-lactamases, and infections with these strains can lead to relatively high mortality rates (approximately 15%). Other virulence factors include production of an antiphagocytic capsule and outer membrane lipopolysaccharide (LPS), which mediates serum resistance, as well as fimbriae on the surface of the bacteria. Type 1 fimbriae mediate adherence to many types of epithelial cells and may facilitate adherence of the bacteria to the bladder epithelium. Type 3 fimbriae can bind in vitro to the extracellular matrix of urinary and respiratory tissues, suggesting that they mediate binding to damaged epithelial surfaces. In addition, type 3 fimbriae are required for biofilm formation by Klebsiella pneumoniae on plastics and human extracellular matrix; thus, they may facilitate the formation of treatment-resistant biofilm on indwelling plastic devices, such as catheters and endotracheal tubing. The presence of these devices may cause tissue damage, allowing Klebsiella to grow as a biofilm on exposed tissue basement membrane components. Though in vivo biofilm growth may be an important step in the infection process, little is known about the genetic factors required for biofilm formation by Klebsiella pneumoniae. Thus, we performed signature-tagged mutagenesis to identify factors produced by K. pneumoniae strain 43816 that are required for biofilm formation. We identified mutations in the cps capsule gene cluster, previously unidentified transcriptional regulators, fimbrial, and sugar phosphotransferase homologues, as well as genetic loci of unknown function, that affect biofilm formation.

scholarly journals Genome Delivery and Ion Channel Properties Are Altered in VP4 Mutants of Poliovirus

2003 ◽  
Vol 77 (9) ◽  
pp. 5266-5274 ◽  
Author(s):  
Pranav Danthi ◽  
Magdalena Tosteson ◽  
Qi-han Li ◽  
Marie Chow
Keyword(s):  
Ion Channels ◽  
Lipid Bilayers ◽  
Conformational Transition ◽  
Channel Structure ◽  
Host Cells ◽  
Lethal Mutant ◽  
Ion Channel Properties ◽  
Type 3

ABSTRACT During entry into host cells, poliovirus undergoes a receptor-mediated conformational transition to form 135S particles with irreversible exposure of VP4 capsid sequences and VP1 N termini. To understand the role of VP4 during virus entry, the fate of VP4 during infection by site-specific mutants at threonine-28 of VP4 (4028T) was compared with that of the parental Mahoney type 1 virus. Three virus mutants were studied: the entry-defective, nonviable mutant 4028T.G and the viable mutants 4028T.S and 4028T.V, in which residue threonine-28 was changed to glycine, serine, and valine, respectively. We show that mutant and wild-type (WT) VP4 proteins are localized to cellular membranes after the 135S conformational transition. Both WT and viable 4028T mutant particles interact with lipid bilayers to form ion channels, whereas the entry-defective 4028T.G particles do not. In addition, the electrical properties of the channels induced by the mutant viruses are different from each other and from those of WT Mahoney and Sabin type 3 viruses. Finally, uncoating and/or cytoplasmic delivery of the viral genome is altered in the 4028T mutants: the 4028T.G lethal mutant does not release its genome into the cytoplasm, and genome delivery is slower during infection by mutant 4028T.V 135S particles than by mutant 4028T.S or WT 135S particles. The distinctive electrical characteristics of the different 4028T mutant channels indicate that VP4 sequences might form part of the channel structure. The different entry phenotypes of these VP4 mutants suggest that the ion channels may be related to VP4's role during genome uncoating and/or delivery.

scholarly journals Type 1 Does the Two-Step: Type 1 Secretion Substrates with a Functional Periplasmic Intermediate

2018 ◽  
Vol 200 (18) ◽  
Author(s):  
T. Jarrod Smith ◽  
Holger Sondermann ◽  
George A. O'Toole
Keyword(s):  
Biofilm Formation ◽  
Cysteine Proteinase ◽  
Secretion System ◽  
Content Type ◽  
Distinct Subgroup ◽  
One Step ◽  
Step Type ◽  
Extracellular Environment

ABSTRACTBacteria have evolved several secretion strategies for polling and responding to environmental flux and insult. Of these, the type 1 secretion system (T1SS) is known to secrete an array of biologically diverse proteins—from small, <10-kDa bacteriocins to gigantic adhesins with a mass >1 MDa. For the last several decades, T1SSs have been characterized as a one-step translocation strategy whereby the secreted substrate is transported directly into the extracellular environment from the cytoplasm with no periplasmic intermediate. Recent phylogenetic, biochemical, and genetic evidences point to a distinct subgroup of T1SS machinery linked with a bacterial transglutaminase-like cysteine proteinase (BTLCP), which uses a two-step secretion mechanism. BTLCP-linked T1SSs transport a class of repeats-in-toxin (RTX) adhesins that are critical for biofilm formation. The prototype of this RTX adhesin group, LapA ofPseudomonas fluorescensPf0-1, uses a novel N-terminal retention module to anchor the adhesin at the cell surface as a secretion intermediate threaded through the outer membrane-localized TolC-like protein LapE. This secretion intermediate is posttranslationally cleaved by the BTLCP family LapG protein to release LapA from its cognate T1SS pore. Thus, the secretion of LapA and related RTX adhesins into the extracellular environment appears to be a T1SS-mediated two-step process that involves a periplasmic intermediate. In this review, we contrast the T1SS machinery and substrates of the BLTCP-linked two-step secretion process with those of the classical one-step T1SS to better understand the newly recognized and expanded role of this secretion machinery.

Sign in / Sign up

Export Citation Format

Share Document