Karen A. Krogfelt

A phylogenetic group of Escherichia coliassociated with active left-sided Inflammatory Bowel Disease (2009)

Petersen, Andreas M, Nielsen, Eva M, Litrup, Eva, Brynskov, Jørn, Mirsepasi, Hengameh, Krogfelt, Karen A

Abstract Background Escherichia coli have been found in increased numbers in tissues from patients with Inflammatory Bowel Disease (IBD) and adherent-invasive E. coli have been found in resected...

Host-pathogen interactions in campylobacter infections: the host perspective (2008)

Janssen, Riny, Krogfelt, Karen A., Cawthraw, Shaun A., Pelt, Wilfrid Van, Wagenaar, J.A., Owen, Robert J.

Campylobacter is a major cause of acute bacterial diarrhea in humans worldwide (3). The incidence of human campylobacteriosis increased exponentially during the last decade of the 20th century (183),...

Transfer of antimicrobial resistance plasmids from Klebsiella pneumoniae to Escherichia coli in the mouse intestine (2008)

Schjørring, Susanne, Struve, Carsten, Krogfelt, Karen A.

Objectives and methods Klebsiella pneumoniae is a nosocomial pathogen and is considered the most common Gram-negative bacterium that exhibits multiple antimicrobial resistances. In this study, the...

Capsule and fimbria interaction in Klebsiella pneumoniae (2005)

Schembri, Mark A., Blom, Jens, Krogfelt, Karen A., Klemm, Per

The capsular polysaccharide and type I fimbriae are two of the major surface-located virulence properties associated with the pathogenesis of Klebsiella pneumoniae. The capsule is an elaborate...

Capsule and fimbria interaction in Klebsiella pneumoniae (2005)

Schembri, Mark A., Blom, Jens, Krogfelt, Karen A., Klemm, Per

The capsular polysaccharide and type I fimbriae are two of the major surface-located virulence properties associated with the pathogenesis of Klebsiella pneumoniae. The capsule is an elaborate...

Specific phospholipids enhance the activity of {beta}-lactam antibiotics against Pseudomonas aeruginosa (2000)

Krogfelt, Karen A., Utley, Maryjane, Krivan, Howard C., Laux, David C., Cohen, Paul S.

Pseudomonas aeruginosa PAO1 became considerably more sensitive to the action of ampicillin when grown in the presence of certain phospholipids. Only phospholipids capable of forming lipid bilayers or...

Pathogenic adaptation of Escherichia coli by natural variation of the FimH adhesin

Sokurenko, Evgeni V., Chesnokova, Veronika, Dykhuizen, Daniel E., Ofek, Itzhak, Wu, Xue-Ru, Krogfelt, Karen A., ...

Conventional wisdom regarding mechanisms of bacterial pathogenesis holds that pathogens arise by external acquisition of distinct virulence factors, whereas determinants shared by pathogens and...

Development of a Long-Term Ascending Urinary Tract Infection Mouse Model for Antibiotic Treatment Studies

Hvidberg, Hanne, Struve, Carsten, Krogfelt, Karen A., Christensen, Nils, Rasmussen, Søren N., Frimodt-Møller, Niels

A model of ascending unobstructed urinary tract infection (UTI) in mice was developed to study the significance of the antibiotic concentration in urine, serum, and kidney tissue for efficacy of...

N-Acyl-l-Homoserine Lactone-Mediated Regulation of the Lip Secretion System in Serratia liquefaciens MG1

Riedel, Kathrin, Ohnesorg, Thomas, Krogfelt, Karen A., Hansen, Thomas S., Omori, Kenji, Givskov, Michael, ...

The analysis of Serratia liquefaciens MG1 ′luxAB insertion mutants that are responsive to N-butanoyl-l-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing...

rpoS Gene Function Is a Disadvantage for Escherichia coli BJ4 during Competitive Colonization of the Mouse Large Intestine

Krogfelt, Karen A., Hjulgaard, Marianne, Sørensen, Kristine, Cohen, Paul S., Givskov, Michael

The ability of Escherichia coli to survive stress during growth in different environments is, in large part, dependent on rpoS and the genes that comprise the rpoS regulon. E. coli BJ4 and an...

A Functional cra Gene Is Required for Salmonella enterica Serovar Typhimurium Virulence in BALB/c Mice

Allen, James H., Utley, Maryjane, Van Den Bosch, Han, Nuijten, Piet, Witvliet, Maarten, McCormick, Beth A., ...

A minitransposon mutant of Salmonella enterica serovar Typhimurium SR-11, SR-11 Fad−, is unable to utilize gluconeogenic substrates as carbon sources and is avirulent and immunogenic when...

Estimation of Growth Rates of Escherichia coli BJ4 in Streptomycin-Treated and Previously Germfree Mice by In Situ rRNA Hybridization

Rang, Camilla U., Licht, Tine Rask, Midtvedt, Tore, Conway, Patricia L., Chao, Lin, Krogfelt, Karen A., ...

The growth physiology of Escherichia coli during colonization of the intestinal tract was studied with four animal models: the streptomycin-treated mouse carrying a reduced microflora, the...

An Escherichia coli MG1655 Lipopolysaccharide Deep-Rough Core Mutant Grows and Survives in Mouse Cecal Mucus but Fails To Colonize the Mouse Large Intestine

Møller, Annette K., Leatham, Mary P., Conway, Tyrrell, Nuijten, Piet J. M., Krogfelt, Karen A., ...

The ability of E. coli strains to colonize the mouse large intestine has been correlated with their ability to grow in cecal and colonic mucus. In the present study, an E. coli MG1655 strain was...

Capsule and Fimbria Interaction in Klebsiella pneumoniae

Schembri, Mark A., Blom, Jens, Krogfelt, Karen A., Klemm, Per

The capsular polysaccharide and type 1 fimbriae are two of the major surface-located virulence properties associated with the pathogenesis of Klebsiella pneumoniae. The capsule is an elaborate...

Mouse Intestine Selects Nonmotile flhDC Mutants of Escherichia coli MG1655 with Increased Colonizing Ability and Better Utilization of Carbon Sources

Leatham, Mary P., Stevenson, Sarah J., Gauger, Eric J., Krogfelt, Karen A., Lins, Jeremy J., Haddock, Traci L., ...

d-Gluconate which is primarily catabolized via the Entner-Doudoroff (ED) pathway, has been implicated as being important for colonization of the streptomycin-treated mouse large intestine by...

In Vitro Biofilm Formation of Commensal and Pathogenic Escherichia coli Strains: Impact of Environmental and Genetic Factors

Reisner, Andreas, Krogfelt, Karen A., Klein, Bjarke M., Zechner, Ellen L., Molin, Søren

Our understanding of Escherichia coli biofilm formation in vitro is based on studies of laboratory K-12 strains grown in standard media. However, pathogenic E. coli isolates differ substantially in...

Pathogenic adaptation of Escherichia coli by natural variation of the FimH adhesin

Sokurenko, Evgeni V., Chesnokova, Veronika, Dykhuizen, Daniel E., Ofek, Itzhak, Wu, Xue-Ru, Krogfelt, Karen A., ...

Conventional wisdom regarding mechanisms of bacterial pathogenesis holds that pathogens arise by external acquisition of distinct virulence factors, whereas determinants shared by pathogens and...

Development of a Long-Term Ascending Urinary Tract Infection Mouse Model for Antibiotic Treatment Studies

Hvidberg, Hanne, Struve, Carsten, Krogfelt, Karen A., Christensen, Nils, Rasmussen, Søren N., Frimodt-Møller, Niels

A model of ascending unobstructed urinary tract infection (UTI) in mice was developed to study the significance of the antibiotic concentration in urine, serum, and kidney tissue for efficacy of...

N-Acyl-l-Homoserine Lactone-Mediated Regulation of the Lip Secretion System in Serratia liquefaciens MG1

Riedel, Kathrin, Ohnesorg, Thomas, Krogfelt, Karen A., Hansen, Thomas S., Omori, Kenji, Givskov, Michael, ...

The analysis of Serratia liquefaciens MG1 ′luxAB insertion mutants that are responsive to N-butanoyl-l-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing...

rpoS Gene Function Is a Disadvantage for Escherichia coli BJ4 during Competitive Colonization of the Mouse Large Intestine

Krogfelt, Karen A., Hjulgaard, Marianne, Sørensen, Kristine, Cohen, Paul S., Givskov, Michael

The ability of Escherichia coli to survive stress during growth in different environments is, in large part, dependent on rpoS and the genes that comprise the rpoS regulon. E. coli BJ4 and an...

A Functional cra Gene Is Required for Salmonella enterica Serovar Typhimurium Virulence in BALB/c Mice

Allen, James H., Utley, Maryjane, Van Den Bosch, Han, Nuijten, Piet, Witvliet, Maarten, McCormick, Beth A., ...

A minitransposon mutant of Salmonella enterica serovar Typhimurium SR-11, SR-11 Fad−, is unable to utilize gluconeogenic substrates as carbon sources and is avirulent and immunogenic when...

Estimation of Growth Rates of Escherichia coli BJ4 in Streptomycin-Treated and Previously Germfree Mice by In Situ rRNA Hybridization

Rang, Camilla U., Licht, Tine Rask, Midtvedt, Tore, Conway, Patricia L., Chao, Lin, Krogfelt, Karen A., ...

The growth physiology of Escherichia coli during colonization of the intestinal tract was studied with four animal models: the streptomycin-treated mouse carrying a reduced microflora, the...

An Escherichia coli MG1655 Lipopolysaccharide Deep-Rough Core Mutant Grows and Survives in Mouse Cecal Mucus but Fails To Colonize the Mouse Large Intestine

Møller, Annette K., Leatham, Mary P., Conway, Tyrrell, Nuijten, Piet J. M., Krogfelt, Karen A., ...

The ability of E. coli strains to colonize the mouse large intestine has been correlated with their ability to grow in cecal and colonic mucus. In the present study, an E. coli MG1655 strain was...

Capsule and Fimbria Interaction in Klebsiella pneumoniae

Schembri, Mark A., Blom, Jens, Krogfelt, Karen A., Klemm, Per

The capsular polysaccharide and type 1 fimbriae are two of the major surface-located virulence properties associated with the pathogenesis of Klebsiella pneumoniae. The capsule is an elaborate...

Mouse Intestine Selects Nonmotile flhDC Mutants of Escherichia coli MG1655 with Increased Colonizing Ability and Better Utilization of Carbon Sources

Leatham, Mary P., Stevenson, Sarah J., Gauger, Eric J., Krogfelt, Karen A., Lins, Jeremy J., Haddock, Traci L., ...

d-Gluconate which is primarily catabolized via the Entner-Doudoroff (ED) pathway, has been implicated as being important for colonization of the streptomycin-treated mouse large intestine by...

In Vitro Biofilm Formation of Commensal and Pathogenic Escherichia coli Strains: Impact of Environmental and Genetic Factors

Reisner, Andreas, Krogfelt, Karen A., Klein, Bjarke M., Zechner, Ellen L., Molin, Søren

Our understanding of Escherichia coli biofilm formation in vitro is based on studies of laboratory K-12 strains grown in standard media. However, pathogenic E. coli isolates differ substantially in...

Kinetics of the Human Antibody Response against Salmonella enterica Serovars Enteritidis and Typhimurium Determined by Lipopolysaccharide Enzyme-Linked Immunosorbent Assay▿

Strid, Mette A., Dalby, Tine, Mølbak, Kåre, Krogfelt, Karen A.

Two indirect enzyme-linked immunosorbent assays (ELISAs) were employed to measure levels of immunoglobulin G (IgG), IgM, and IgA antibodies against Salmonella in sera from 303 Danish patients...

Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice

Fouts, Derrick E., Tyler, Heather L., DeBoy, Robert T., Daugherty, Sean, Ren, Qinghu, Badger, Jonathan H., ...

We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a...

Glycogen and Maltose Utilization by Escherichia coli O157:H7 in the Mouse Intestine▿

Jones, Shari A., Jorgensen, Mathias, Chowdhury, Fatema Z., Rodgers, Rosalie, Hartline, James, Leatham, Mary P., ...

Mutant screens and transcriptome studies led us to consider whether the metabolism of glucose polymers, i.e., maltose, maltodextrin, and glycogen, is important for Escherichia coli colonization of...

New Adhesin of Enteroaggregative Escherichia coli Related to the Afa/Dr/AAF Family▿

Boisen, Nadia, Struve, Carsten, Scheutz, Flemming, Krogfelt, Karen A., Nataro, James P.

Enteroaggregative Escherichia coli (EAEC) is an important cause of diarrhea worldwide. We analyzed 17 Danish EAEC strains, isolated in the course of a case control study, for phenotypic and genotypic...

Pneumococcal Serotypes and Mortality following Invasive Pneumococcal Disease: A Population-Based Cohort Study

Harboe, Zitta B., Thomsen, Reimar W., Riis, Anders, Valentiner-Branth, Palle, Christensen, Jens Jørgen, Lambertsen, Lotte, ...

Analyzing population-based data collected over 30 years in more than 18,000 patients with invasive pneumococcal infection, Zitta Harboe and colleagues find specific pneumococcal serotypes to be...

Host-Pathogen Interactions in Campylobacter Infections: the Host Perspective

Janssen, Riny, Krogfelt, Karen A., Cawthraw, Shaun A., Van Pelt, Wilfrid, Wagenaar, Jaap A., Owen, Robert J.

Campylobacter is a major cause of acute bacterial diarrhea in humans worldwide. This study was aimed at summarizing the current understanding of host mechanisms involved in the defense against...