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Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length

Klebsiella pneumoniae is a hospital-associated pathogen primarily causing urinary tract infections (UTIs), pneumonia, and septicemia. Two challenging lineages include the hypervirulent strains, causing invasive community-acquired infections, and the carbapenem-resistant classical strains, most frequ...

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Autores principales: Khadka, Saroj, Ring, Brooke E., Walker, Ryan S., Krzeminski, Lindsey R., Pariseau, Drew A., Hathaway, Matthew, Mobley, Harry L. T., Mike, Laura A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10597399/
https://www.ncbi.nlm.nih.gov/pubmed/37610214
http://dx.doi.org/10.1128/msphere.00288-23
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author Khadka, Saroj
Ring, Brooke E.
Walker, Ryan S.
Krzeminski, Lindsey R.
Pariseau, Drew A.
Hathaway, Matthew
Mobley, Harry L. T.
Mike, Laura A.
author_facet Khadka, Saroj
Ring, Brooke E.
Walker, Ryan S.
Krzeminski, Lindsey R.
Pariseau, Drew A.
Hathaway, Matthew
Mobley, Harry L. T.
Mike, Laura A.
author_sort Khadka, Saroj
collection PubMed
description Klebsiella pneumoniae is a hospital-associated pathogen primarily causing urinary tract infections (UTIs), pneumonia, and septicemia. Two challenging lineages include the hypervirulent strains, causing invasive community-acquired infections, and the carbapenem-resistant classical strains, most frequently isolated from UTIs. While hypervirulent strains are often characterized by a hypermucoid phenotype, classical strains usually present with low mucoidy. Since clinical UTI isolates tend to exhibit limited mucoidy, we hypothesized that environmental conditions may drive K. pneumoniae adaptation to the urinary tract and select against mucoid isolates. We found that both hypervirulent K. pneumoniae and classical Klebsiella UTI isolates significantly suppressed mucoidy when cultured in urine without reducing capsule abundance. A genetic screen identified secondary mutations in the wzc tyrosine kinase that overcome urine-suppressed mucoidy. Over-expressing Wzc variants in trans was sufficient to boost mucoidy in both hypervirulent and classical Klebsiella UTI isolates. Wzc is a bacterial tyrosine kinase that regulates capsule polymerization and extrusion. Although some Wzc variants reduced Wzc phospho-status, urine did not alter Wzc phospho-status. Urine does, however, increase K. pneumoniae capsule chain length diversity and enhance cell-surface attachment. The identified Wzc variants counteract urine-mediated effects on capsule chain length and cell attachment. Combined, these data indicate that capsule chain length correlates with K. pneumoniae mucoidy and that this extracellular feature can be fine-tuned by spontaneous Wzc mutations, which alter host interactions. Spontaneous Wzc mutation represents a global mechanism that could fine-tune K. pneumoniae niche-specific fitness in both classical and hypervirulent isolates. IMPORTANCE: Klebsiella pneumoniae is high-priority pathogen causing both hospital-associated infections, such as urinary tract infections, and community-acquired infections. Clinical isolates from community-acquired infection are often characterized by a tacky, hypermucoid phenotype, while urinary tract isolates are usually not mucoid. Historically, mucoidy was attributed to capsule overproduction; however, recent reports have demonstrated that K. pneumoniae capsule abundance and mucoidy are not always correlated. Here, we report that human urine suppresses K. pneumoniae mucoidy, diversifies capsule polysaccharide chain length, and increases cell surface association. Moreover, specific mutations in the capsule biosynthesis gene, wzc, are sufficient to overcome urine-mediated suppression of mucoidy. These Wzc variants cause constitutive production of more uniform capsular polysaccharide chains and increased release of capsule from the cell surface, even in urine. These data demonstrate that K. pneumoniae regulates capsule chain length and cell surface attachment in response host cues, which can alter bacteria-host interactions.
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spelling pubmed-105973992023-10-25 Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length Khadka, Saroj Ring, Brooke E. Walker, Ryan S. Krzeminski, Lindsey R. Pariseau, Drew A. Hathaway, Matthew Mobley, Harry L. T. Mike, Laura A. mSphere Research Article Klebsiella pneumoniae is a hospital-associated pathogen primarily causing urinary tract infections (UTIs), pneumonia, and septicemia. Two challenging lineages include the hypervirulent strains, causing invasive community-acquired infections, and the carbapenem-resistant classical strains, most frequently isolated from UTIs. While hypervirulent strains are often characterized by a hypermucoid phenotype, classical strains usually present with low mucoidy. Since clinical UTI isolates tend to exhibit limited mucoidy, we hypothesized that environmental conditions may drive K. pneumoniae adaptation to the urinary tract and select against mucoid isolates. We found that both hypervirulent K. pneumoniae and classical Klebsiella UTI isolates significantly suppressed mucoidy when cultured in urine without reducing capsule abundance. A genetic screen identified secondary mutations in the wzc tyrosine kinase that overcome urine-suppressed mucoidy. Over-expressing Wzc variants in trans was sufficient to boost mucoidy in both hypervirulent and classical Klebsiella UTI isolates. Wzc is a bacterial tyrosine kinase that regulates capsule polymerization and extrusion. Although some Wzc variants reduced Wzc phospho-status, urine did not alter Wzc phospho-status. Urine does, however, increase K. pneumoniae capsule chain length diversity and enhance cell-surface attachment. The identified Wzc variants counteract urine-mediated effects on capsule chain length and cell attachment. Combined, these data indicate that capsule chain length correlates with K. pneumoniae mucoidy and that this extracellular feature can be fine-tuned by spontaneous Wzc mutations, which alter host interactions. Spontaneous Wzc mutation represents a global mechanism that could fine-tune K. pneumoniae niche-specific fitness in both classical and hypervirulent isolates. IMPORTANCE: Klebsiella pneumoniae is high-priority pathogen causing both hospital-associated infections, such as urinary tract infections, and community-acquired infections. Clinical isolates from community-acquired infection are often characterized by a tacky, hypermucoid phenotype, while urinary tract isolates are usually not mucoid. Historically, mucoidy was attributed to capsule overproduction; however, recent reports have demonstrated that K. pneumoniae capsule abundance and mucoidy are not always correlated. Here, we report that human urine suppresses K. pneumoniae mucoidy, diversifies capsule polysaccharide chain length, and increases cell surface association. Moreover, specific mutations in the capsule biosynthesis gene, wzc, are sufficient to overcome urine-mediated suppression of mucoidy. These Wzc variants cause constitutive production of more uniform capsular polysaccharide chains and increased release of capsule from the cell surface, even in urine. These data demonstrate that K. pneumoniae regulates capsule chain length and cell surface attachment in response host cues, which can alter bacteria-host interactions. American Society for Microbiology 2023-08-23 /pmc/articles/PMC10597399/ /pubmed/37610214 http://dx.doi.org/10.1128/msphere.00288-23 Text en Copyright © 2023 Khadka et al. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Khadka, Saroj
Ring, Brooke E.
Walker, Ryan S.
Krzeminski, Lindsey R.
Pariseau, Drew A.
Hathaway, Matthew
Mobley, Harry L. T.
Mike, Laura A.
Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title_full Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title_fullStr Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title_full_unstemmed Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title_short Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length
title_sort urine-mediated suppression of klebsiella pneumoniae mucoidy is counteracted by spontaneous wzc variants altering capsule chain length
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10597399/
https://www.ncbi.nlm.nih.gov/pubmed/37610214
http://dx.doi.org/10.1128/msphere.00288-23
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