Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity
ABSTRACT Klebsiella pneumoniae can be broadly classified into classical strains that cause drug-resistant, hospital-associated infections and hypervirulent strains that cause invasive, community-acquired, drug-susceptible infections. Hypermucoviscosity in Klebsiella pneumoniae has been associated wi...
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2022-06-01
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| Series: | Microbiology Spectrum |
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| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.00393-22 |
| _version_ | 1811238467714154496 |
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| author | Tamal Dey Ardhendu Chakrabortty Aastha Kapoor Anuja Warrier Vijaya Lakshmi Nag Karthikeyan Sivashanmugam Manoharan Shankar |
| author_facet | Tamal Dey Ardhendu Chakrabortty Aastha Kapoor Anuja Warrier Vijaya Lakshmi Nag Karthikeyan Sivashanmugam Manoharan Shankar |
| author_sort | Tamal Dey |
| collection | DOAJ |
| description | ABSTRACT Klebsiella pneumoniae can be broadly classified into classical strains that cause drug-resistant, hospital-associated infections and hypervirulent strains that cause invasive, community-acquired, drug-susceptible infections. Hypermucoviscosity in Klebsiella pneumoniae has been associated with immune evasion and hypervirulence. A string-test-positive, hypermucoviscous strain of Klebsiella pneumoniae, P34, was isolated from the cystic lesion of a patient who reported to a tertiary care hospital in Jodhpur, Rajasthan, India. Given the antibiotic-susceptible and hypermucoviscous nature of the isolate, it was suspected to belong to the hypervirulent lineage of Klebsiella pneumoniae. However, P34 did not overproduce capsular polysaccharides and also remained susceptible to the antimicrobial effects of human serum when tested alongside strains that were non-hypermucoviscous. Sequencing of the genome of P34 revealed the absence of any large virulence plasmids or integrative conjugative elements that usually carry hypermucoviscosity- and hypervirulence-associated genes. P34 also lacked key virulence determinants such as aerobactin, yersiniabactin, and salmochelin biosynthesis clusters. In addition, P34 lacked homologs for genes associated with enhanced capsule synthesis and hypermucoviscosity, such as rmpA, rmpA2, rmpC, and rmpD (regulator of mucoid phenotype). These observations suggest that P34 may harbor novel genetic determinants of hypermucoviscosity independent of the indirectly acting rmpA and the recently described rmpD. IMPORTANCE Hypermucoviscosity is a characteristic of hypervirulent Klebsiella pneumoniae strains, which are capable of causing invasive disease in community settings. This study reports phenotyping and genomic analysis of an unusual clinical isolate of Klebsiella pneumoniae, P34, which exhibits hypermucoviscosity and yet does not harbor rmp (regulator of mucoid phenotype) genes, which are known determinants of hypermucoviscosity (rmpA and rmpD). Similar clinical isolates belonging to the K. pneumoniae complex that are hypermucoviscous but do not harbor the rmp loci have been reported from India and abroad, indicating the prevalence of unknown determinants contributing to hypermucoviscosity. Therefore, strains like P34 will serve as model systems to mechanistically study potentially novel determinants of hypermucoviscosity in the K. pneumoniae complex. |
| first_indexed | 2024-04-12T12:41:55Z |
| format | Article |
| id | doaj.art-a55278230ea84cc8bf59878f4ed36776 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-04-12T12:41:55Z |
| publishDate | 2022-06-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-a55278230ea84cc8bf59878f4ed367762022-12-22T03:32:45ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972022-06-0110310.1128/spectrum.00393-22Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of HypermucoviscosityTamal Dey0Ardhendu Chakrabortty1Aastha Kapoor2Anuja Warrier3Vijaya Lakshmi Nag4Karthikeyan Sivashanmugam5Manoharan Shankar6Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, IndiaDepartment of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, IndiaDepartment of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, IndiaDepartment of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, IndiaDepartment of Microbiology, All India Institute of Medical Sciences Jodhpur, Jodhpur, Rajasthan, IndiaSchool of Bio Sciences and Technology, Vellore Institute of Technology University, Vellore, Tamil Nadu, IndiaDepartment of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, IndiaABSTRACT Klebsiella pneumoniae can be broadly classified into classical strains that cause drug-resistant, hospital-associated infections and hypervirulent strains that cause invasive, community-acquired, drug-susceptible infections. Hypermucoviscosity in Klebsiella pneumoniae has been associated with immune evasion and hypervirulence. A string-test-positive, hypermucoviscous strain of Klebsiella pneumoniae, P34, was isolated from the cystic lesion of a patient who reported to a tertiary care hospital in Jodhpur, Rajasthan, India. Given the antibiotic-susceptible and hypermucoviscous nature of the isolate, it was suspected to belong to the hypervirulent lineage of Klebsiella pneumoniae. However, P34 did not overproduce capsular polysaccharides and also remained susceptible to the antimicrobial effects of human serum when tested alongside strains that were non-hypermucoviscous. Sequencing of the genome of P34 revealed the absence of any large virulence plasmids or integrative conjugative elements that usually carry hypermucoviscosity- and hypervirulence-associated genes. P34 also lacked key virulence determinants such as aerobactin, yersiniabactin, and salmochelin biosynthesis clusters. In addition, P34 lacked homologs for genes associated with enhanced capsule synthesis and hypermucoviscosity, such as rmpA, rmpA2, rmpC, and rmpD (regulator of mucoid phenotype). These observations suggest that P34 may harbor novel genetic determinants of hypermucoviscosity independent of the indirectly acting rmpA and the recently described rmpD. IMPORTANCE Hypermucoviscosity is a characteristic of hypervirulent Klebsiella pneumoniae strains, which are capable of causing invasive disease in community settings. This study reports phenotyping and genomic analysis of an unusual clinical isolate of Klebsiella pneumoniae, P34, which exhibits hypermucoviscosity and yet does not harbor rmp (regulator of mucoid phenotype) genes, which are known determinants of hypermucoviscosity (rmpA and rmpD). Similar clinical isolates belonging to the K. pneumoniae complex that are hypermucoviscous but do not harbor the rmp loci have been reported from India and abroad, indicating the prevalence of unknown determinants contributing to hypermucoviscosity. Therefore, strains like P34 will serve as model systems to mechanistically study potentially novel determinants of hypermucoviscosity in the K. pneumoniae complex.https://journals.asm.org/doi/10.1128/spectrum.00393-22Klebsiella pneumoniaehypermucoviscositycapsulecapsular polysaccharidevirulence |
| spellingShingle | Tamal Dey Ardhendu Chakrabortty Aastha Kapoor Anuja Warrier Vijaya Lakshmi Nag Karthikeyan Sivashanmugam Manoharan Shankar Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity Microbiology Spectrum Klebsiella pneumoniae hypermucoviscosity capsule capsular polysaccharide virulence |
| title | Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity |
| title_full | Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity |
| title_fullStr | Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity |
| title_full_unstemmed | Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity |
| title_short | Unusual Hypermucoviscous Clinical Isolate of Klebsiella pneumoniae with No Known Determinants of Hypermucoviscosity |
| title_sort | unusual hypermucoviscous clinical isolate of klebsiella pneumoniae with no known determinants of hypermucoviscosity |
| topic | Klebsiella pneumoniae hypermucoviscosity capsule capsular polysaccharide virulence |
| url | https://journals.asm.org/doi/10.1128/spectrum.00393-22 |
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