Capsule deletion via a λ-Red knockout system perturbs biofilm formation and fimbriae expression in Klebsiella pneumoniae MGH 78578

Huang, Tzu Wen; Lam, Irene; Chang, Hwan‐You; Tsai, Shih Feng; Palsson, Bernhard Ø.; Charusanti, Pep

doi:10.1186/1756-0500-7-13

Cited by 72 publications

(56 citation statements)

References 41 publications

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“…K. pneumoniae transposon-insertion mutants were generated by introducing a kanamycin-resistant (Kan r ) Himar1 transposon into K. pneumoniae by mating MKP220 with the DAP auxotrophic MFDpir-pSC189 (MKP216) (62), and insertion sites were confirmed by PCR as described in the supplemental material. All deletion mutants were generated using lambda red recombination as described in the supplemental material (63). Clinical isolates from blood (B) and respiratory (R) infections at Ohio State University were used.…”

Section: Methodsmentioning

confidence: 99%

Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection

Silver

Paczosa

McCabe

et al. 2019

Antimicrob Agents Chemother

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The emergence of multidrug-resistant Klebsiella pneumoniae has rendered a large array of infections difficult to treat. In a high-throughput genetic screen of factors required for K. pneumoniae survival in the lung, amino acid biosynthesis genes were critical for infection in both immunosuppressed and wild-type (WT) mice. The limited pool of amino acids in the lung did not change during infection and was insufficient for K. pneumoniae to overcome attenuating mutations in aroA, hisA, leuA, leuB, serA, serB, trpE, and tyrA in WT and immunosuppressed mice. Deletion of aroA, which encodes 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase class I, resulted in the most severe attenuation. Treatment with the EPSP synthase-specific competitive inhibitor glyphosate decreased K. pneumoniae growth in the lungs. K. pneumoniae expressing two previously identified glyphosate-resistant mutations in EPSP synthase had significant colonization defects in lung infection. Selection and characterization of six spontaneously glyphosate-resistant mutants in K. pneumoniae yielded no mutations in aroA. Strikingly, glyphosate treatment of mice lowered the bacterial burden of two of three spontaneous glyphosate-resistant mutants and further lowered the burden of the less-attenuated EPSP synthase catalytic mutant. Of 39 clinical isolate strains, 9 were resistant to glyphosate at levels comparable to those of selected resistant strains, and none appeared to be more highly resistant. These findings demonstrate amino acid biosynthetic pathways essential for K. pneumoniae infection are promising novel therapeutic targets.

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Section: Methodsmentioning

confidence: 99%

Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection

Silver

Paczosa

McCabe

et al. 2019

Antimicrob Agents Chemother

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“…K. pneumoniae biofilm formation is well appreciated, but the genetic basis for biofilm formation is unclear. Varying reports attribute the biofilm phenotype to capsule [139,140] and/ or fimbriae [140][141][142], whilst others have shown lack of capsule enhances biofilm formation [143]. hvKp strains seem to be more robust biofilm producers in the laboratory relative to non-tissue-invasive isolates in a survey of more than 70 isolates [140].…”

Section: Additional Hvkp Virulence Factorsmentioning

confidence: 96%

Hypervirulent Klebsiella pneumoniae – clinical and molecular perspectives

2019

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Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a concerning global pathogen. hvKp is more virulent than classical K. pneumoniae (cKp) and capable of causing community‐acquired infections, often in healthy individuals. hvKp is carried in the gastrointestinal tract, which contributes to its spread in the community and healthcare settings. First recognized in Asia, hvKp arose as a leading cause of pyogenic liver abscesses. In the decades since, hvKp has spread globally and causes a variety of infections. In addition to liver abscesses, hvKp is distinct from cKp in its ability to metastasize to distant sites, including most commonly the eye, lung and central nervous system (CNS). hvKp has also been implicated in primary extrahepatic infections including bacteremia, pneumonia and soft tissue infections. The genetic determinants of hypervirulence are often found on large virulence plasmids as well as chromosomal mobile genetic elements which can be used as biomarkers to distinguish hvKp from cKp clinical isolates. These distinct virulence determinants of hvKp include up to four siderophore systems for iron acquisition, increased capsule production, K1 and K2 capsule types, and the colibactin toxin. Additionally, hvKp strains demonstrate hypermucoviscosity, a phenotypic description of hvKp in laboratory conditions that has become a distinguishing feature of many hypervirulent isolates. Alarmingly, multidrug‐resistant hypervirulent strains have emerged, creating a new challenge in combating this already dangerous pathogen.

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“…The interference of bacterial capsulation with underlying adhesins to cause reduced bacterial attachment or biofilm formation is a well-recognised observation in K. pneumoniae. For instance, capsule expression was shown to block the activity of Antigen 43 [59], and defects in exopolysaccharide synthesis promoted increased bacterial adherence, possibly as a result of more opportunities for cell-surface and/ or intercellular interactions [47,[60][61][62][63].…”

Section: Assessment Of Biofilm Formation By a K Pneumoniae δLuxs Mutantmentioning

confidence: 99%

Investigation of LuxS-mediated quorum sensing in Klebsiella pneumoniae

Chen

Wilksch

Liu

et al. 2020

Journal of Medical Microbiology

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Introduction. Autoinducer-2 (AI-2) quorum sensing is a bacterial communication system that responds to cell density. The system requires luxS activity to produce AI-2, which can regulate gene expression and processes such as biofilm formation. Aim. To investigate the role of luxS in biofilm formation and gene expression in the nosocomial pathogen Klebsiella pneumoniae . Methodology. A ΔluxS gene deletion was made in K. pneumoniae KP563, an extensively drug-resistant isolate. AI-2 production was assessed in wild-type and ΔluxS strains grown in media supplemented with different carbohydrates. Potential roles of luxS in biofilm formation were investigated using a microtiter plate biofilm assay and scanning electron microscopy. Quantitative RT-PCR evaluated the expression of lipopolysaccharide (wzm and wbbM), polysaccharide (pgaA), and type 3 fimbriae (mrkA) synthesis genes in wild-type and ΔluxS mutant biofilm extracts. Results. AI-2 production was dependent on the presence of luxS. AI-2 accumulation was highest during early stationary phase in media supplemented with glucose, sucrose or glycerol. Changes in biofilm architecture were observed in the ΔluxS mutant, with less surface coverage and reduced macrocolony formation; however, no differences in biofilm formation between the wild-type and ΔluxS mutant using a microtiter plate assay were observed. In ΔluxS mutant biofilm extracts, the expression of wzm was down-regulated, and the expression of pgaA, which encodes a porin for poly-β−1,6-N-acetyl-d-glucosamine (PNAG) polysaccharide secretion, was upregulated. Conclusion. Relationships among AI-2-mediated quorum sensing, biofilm formation and gene expression of outer-membrane components were identified in K. pneumoniae . These inter-connected processes could be important for bacterial group behaviour and persistence.

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Capsule deletion via a λ-Red knockout system perturbs biofilm formation and fimbriae expression in Klebsiella pneumoniae MGH 78578

Cited by 72 publications

References 41 publications

Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection

Amino Acid Biosynthetic Pathways Are Required for Klebsiella pneumoniae Growth in Immunocompromised Lungs and Are Druggable Targets during Infection

Hypervirulent Klebsiella pneumoniae – clinical and molecular perspectives

Investigation of LuxS-mediated quorum sensing in Klebsiella pneumoniae

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