Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content>
ABSTRACT Klebsiella pneumoniae is rapidly acquiring resistance to all known antibiotics, including carbapenems. Multilocus sequence type ST258 (sequence type 258), carrying a gene encoding the K. pneumoniae carbapenemase (blaKPC) on a transmissible plasmid, is the most prevalent carbapenem-resistant...
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2018-04-01
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| Series: | mSphere |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mSphere.00125-18 |
| _version_ | 1818836608919535616 |
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| author | Victoria I. Holden Meredith S. Wright Sébastien Houle Abigail Collingwood Charles M. Dozois Mark D. Adams Michael A. Bachman |
| author_facet | Victoria I. Holden Meredith S. Wright Sébastien Houle Abigail Collingwood Charles M. Dozois Mark D. Adams Michael A. Bachman |
| author_sort | Victoria I. Holden |
| collection | DOAJ |
| description | ABSTRACT Klebsiella pneumoniae is rapidly acquiring resistance to all known antibiotics, including carbapenems. Multilocus sequence type ST258 (sequence type 258), carrying a gene encoding the K. pneumoniae carbapenemase (blaKPC) on a transmissible plasmid, is the most prevalent carbapenem-resistant Enterobacteriaceae (CRE) in the United States and has disseminated worldwide. Previously, whole-genome sequencing identified core genome single nucleotide variants that divide ST258 into two distinct clades, ST258a and ST258b. Furthermore, a subset of ST258b strains have a 347-base deletion within the enterobactin (Ent) exporter gene entS. Despite the predicted inability of these strains to secrete the siderophore Ent, this clade is prevalent among clinical isolates, indicating that a full-length entS gene is not necessary for infection. To compare the transcriptional responses of ST258 subtypes to iron limitation, we performed transcriptome sequencing (RNA-Seq) in minimal medium alone or supplemented with iron or human serum and measured gene expression patterns. Iron limitation induced differential expression of distinct iron acquisition pathways when comparing ST258a and ST258b strains, including the upregulation of the hemin transport operon in entS partial deletion isolates. To measure how K. pneumoniae strains vary in iron chelation and siderophore production, we performed in vitro chrome azurol S (CAS) and Arnow assays as well as mass spectrometry. We determined that both ST258a and ST258b strains grow under iron-depleted conditions, can utilize hemin for growth, and secrete Ent, despite the partial entS deletion in a subset of ST258b strains. All carbapenem-resistant (CR) K. pneumoniae strains tested were susceptible to growth inhibition by the Ent-sequestering innate immune protein lipocalin 2. IMPORTANCE Carbapenem-resistant Enterobacteriaceae, including K. pneumoniae, are a major health care concern worldwide because they cause a wide range of infection and are resistant to all or nearly all antibiotics. To cause infection, these bacteria must acquire iron, and a major mechanism of acquiring iron is by secreting a molecule called enterobactin that strips iron from host proteins. However, a subset of carbapenem-resistant K. pneumoniae strains that lack a portion of the entS gene that is required for enterobactin secretion was recently discovered. To understand how these mutant strains obtain iron, we studied their transcriptional responses, bacterial growth, and enterobactin secretion under iron-limited conditions. We found that strains both with mutated and intact entS genes grow under iron-limiting conditions, secrete enterobactin, and utilize an alternate iron source, hemin, for growth. Our data indicate that carbapenem-resistant K. pneumoniae can use varied methods for iron uptake during infection. |
| first_indexed | 2024-12-19T03:09:19Z |
| format | Article |
| id | doaj.art-097eaeb490764ebc9206e76d97f3b638 |
| institution | Directory Open Access Journal |
| issn | 2379-5042 |
| language | English |
| last_indexed | 2024-12-19T03:09:19Z |
| publishDate | 2018-04-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mSphere |
| spelling | doaj.art-097eaeb490764ebc9206e76d97f3b6382022-12-21T20:38:03ZengAmerican Society for MicrobiologymSphere2379-50422018-04-013210.1128/mSphere.00125-18Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content>Victoria I. Holden0Meredith S. Wright1Sébastien Houle2Abigail Collingwood3Charles M. Dozois4Mark D. Adams5Michael A. Bachman6Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USAJ. Craig Venter Institute, La Jolla, California, USAInstitut National de Recherche Scientifique, Institut Armand Frappier, Laval, CanadaDepartment of Pathology, University of Michigan, Ann Arbor, Michigan, USAInstitut National de Recherche Scientifique, Institut Armand Frappier, Laval, CanadaJ. Craig Venter Institute, La Jolla, California, USADepartment of Pathology, University of Michigan, Ann Arbor, Michigan, USAABSTRACT Klebsiella pneumoniae is rapidly acquiring resistance to all known antibiotics, including carbapenems. Multilocus sequence type ST258 (sequence type 258), carrying a gene encoding the K. pneumoniae carbapenemase (blaKPC) on a transmissible plasmid, is the most prevalent carbapenem-resistant Enterobacteriaceae (CRE) in the United States and has disseminated worldwide. Previously, whole-genome sequencing identified core genome single nucleotide variants that divide ST258 into two distinct clades, ST258a and ST258b. Furthermore, a subset of ST258b strains have a 347-base deletion within the enterobactin (Ent) exporter gene entS. Despite the predicted inability of these strains to secrete the siderophore Ent, this clade is prevalent among clinical isolates, indicating that a full-length entS gene is not necessary for infection. To compare the transcriptional responses of ST258 subtypes to iron limitation, we performed transcriptome sequencing (RNA-Seq) in minimal medium alone or supplemented with iron or human serum and measured gene expression patterns. Iron limitation induced differential expression of distinct iron acquisition pathways when comparing ST258a and ST258b strains, including the upregulation of the hemin transport operon in entS partial deletion isolates. To measure how K. pneumoniae strains vary in iron chelation and siderophore production, we performed in vitro chrome azurol S (CAS) and Arnow assays as well as mass spectrometry. We determined that both ST258a and ST258b strains grow under iron-depleted conditions, can utilize hemin for growth, and secrete Ent, despite the partial entS deletion in a subset of ST258b strains. All carbapenem-resistant (CR) K. pneumoniae strains tested were susceptible to growth inhibition by the Ent-sequestering innate immune protein lipocalin 2. IMPORTANCE Carbapenem-resistant Enterobacteriaceae, including K. pneumoniae, are a major health care concern worldwide because they cause a wide range of infection and are resistant to all or nearly all antibiotics. To cause infection, these bacteria must acquire iron, and a major mechanism of acquiring iron is by secreting a molecule called enterobactin that strips iron from host proteins. However, a subset of carbapenem-resistant K. pneumoniae strains that lack a portion of the entS gene that is required for enterobactin secretion was recently discovered. To understand how these mutant strains obtain iron, we studied their transcriptional responses, bacterial growth, and enterobactin secretion under iron-limited conditions. We found that strains both with mutated and intact entS genes grow under iron-limiting conditions, secrete enterobactin, and utilize an alternate iron source, hemin, for growth. Our data indicate that carbapenem-resistant K. pneumoniae can use varied methods for iron uptake during infection.https://journals.asm.org/doi/10.1128/mSphere.00125-18CREKlebsiella pneumoniaeST258carbapenemsentSenterobactin |
| spellingShingle | Victoria I. Holden Meredith S. Wright Sébastien Houle Abigail Collingwood Charles M. Dozois Mark D. Adams Michael A. Bachman Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> mSphere CRE Klebsiella pneumoniae ST258 carbapenems entS enterobactin |
| title | Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> |
| title_full | Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> |
| title_fullStr | Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> |
| title_full_unstemmed | Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> |
| title_short | Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 <named-content content-type="genus-species">Klebsiella pneumoniae</named-content> |
| title_sort | iron acquisition and siderophore release by carbapenem resistant sequence type 258 named content content type genus species klebsiella pneumoniae named content |
| topic | CRE Klebsiella pneumoniae ST258 carbapenems entS enterobactin |
| url | https://journals.asm.org/doi/10.1128/mSphere.00125-18 |
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