Pneumonia

Seaton, Douglas

doi:10.1002/9780470695999.ch13

Cited by 6 publications

(4 citation statements)

References 667 publications

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“…Klebsiella pneumoniae is a non‐motile Gram‐negative bacterium that is ubiquitous in the environment and is often found as a commensal resident of the human gastrointestinal tract (Seaton, 2000). When inoculated parenterally, it has a remarkable ability to cause a wide range of human diseases, from urinary tract infections to pneumonia (Sahly and Podschun, 1997).…”

Section: Introductionmentioning

confidence: 99%

Identification of Klebsiella pneumoniae virulence determinants using an intranasal infection model

Lawlor¹,

Hsu

Rick

et al. 2005

Molecular Microbiology

203

225

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SummaryKlebsiella pneumoniae is a Gram-negative enterobacterium that has historically been, and currently remains, a significant cause of human disease. It is a frequent cause of urinary tract infections and pneumonia, and subsequent systemic infections can have mortality rates as high as 60%. Despite its clinical significance, few virulence factors of K. pneumoniae have been identified or characterized. In this study we present a mouse model of acute K. pneumoniae respiratory infection using an intranasal inoculation method, and examine the progression of both pulmonary and systemic disease. Wild-type infection recapitulates many aspects of clinical disease, including significant bacterial growth in both the trachea and lungs, an inflammatory immune response characterized by dramatic neutrophil influx, and a steady progression to systemic disease with ensuing mortality. These observations are contrasted with an infection by an isogenic capsule-deficient strain that shows an inability to cause disease in either pulmonary or systemic tissues. The consistency and clinical accuracy of the intranasal mouse model proved to be a useful tool as we conducted a genetic screen to identify novel virulence factors of K. pneumoniae . A total of 4800 independent insertional mutants were evaluated using a signature-tagged mutagenesis protocol. A total of 106 independent mutants failed to be recovered from either the lungs or spleens of infected mice. Small scale independent infections proved to be helpful as a secondary screening method, as opposed to the more traditional competitive index assay. Those mutants showing verified attenuation contained insertions in loci with a variety of putative functions, including a large number of hypothetical open reading frames. Subsequent experiments support the premise that the central mechanism of K. pneumoniae pathogenesis is the production of a polysaccharide-rich cell surface that provides protection from the inflammatory response.

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Section: Introductionmentioning

confidence: 99%

Identification of Klebsiella pneumoniae virulence determinants using an intranasal infection model

Lawlor¹,

Hsu

Rick

et al. 2005

Molecular Microbiology

203

225

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“…It is a nonmotile, gram-negative bacterium that is typically found as a commensal resident of the mammalian gastrointestinal tract (41). K. pneumoniae is also a substantial cause of human disease, particularly among immunocompromised individuals (39).…”

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confidence: 99%

Yersiniabactin Is a Virulence Factor for Klebsiella pneumoniae during Pulmonary Infection

Lawlor¹,

O’Connor²,

2007

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Iron acquisition systems are essential for the in vivo growth of bacterial pathogens. Despite the epidemiological importance of Klebsiella pneumoniae, few experiments have examined the importance of siderophores in the pathogenesis of this species. A previously reported signature-tagged mutagenesis screen identified an attenuated strain that featured an insertional disruption in ybtQ, which encodes a transporter for the siderophore yersiniabactin. We used this finding as a starting point to evaluate the importance of siderophores in the physiology and pathogenesis of K. pneumoniae. Isogenic strains carrying in-frame deletions in genes required for the synthesis of either enterobactin or yersiniabactin were constructed, and the growth of these mutants was examined both in vitro and in vivo using an intranasal infection model. The results suggest divergent functions for each siderophore in different environments, with enterobactin being more important for growth in vitro under iron limitation than in vivo and the reverse being true for the yersiniabactin locus. These observations represent the first examination of isogenic mutants in iron acquisition systems for K. pneumoniae and may indicate that the acquisition of nonenterobactin siderophores is an important step in the evolution of virulent enterobacterial strains.

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“…Residual pulmonary or parenchymal shadowing is not uncommon after successful treatment of the staphylococcal pneumonia and its intrathoracic complications. 1 …”

Section: Discussionmentioning

confidence: 99%

“…Loculated pyopneumothorax can occur as a complication of staphylococcal bacteremia, but even after successful treatment, some residual pulmonary or pleural shadowing may persist. 1 Complete radiological clearing by conservative management with antibiotics alone is being reported here for the purpose of clinical interest owing to reports on this condition being scanty in the literature.…”

Section: Introductionmentioning

confidence: 90%

Complete radiological clearance in bilateral loculated pyopneumothorax managed conservatively

Verma

Mahajan

2009

Lung India

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Pneumonia

Cited by 6 publications

References 667 publications

Identification of Klebsiella pneumoniae virulence determinants using an intranasal infection model

Identification of Klebsiella pneumoniae virulence determinants using an intranasal infection model

Yersiniabactin Is a Virulence Factor for Klebsiella pneumoniae during Pulmonary Infection

Complete radiological clearance in bilateral loculated pyopneumothorax managed conservatively

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