Phenotypic and genotypic analysis of hypermucoviscous Klebsiella pneumoniae (hmkp) strain
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Abstract
Background and Objectives: Hypermucoviscous Klebsiella pneumoniae exhibits distinct phenotypic and genetic characteristics that distinguish it from the classic K. pneumoniae pathogen. The aim of current study was to investigate some phenotypic and genetic markers used for hmKp identification.
Materials and Methods: Seventy-one K. pneumoniae isolates were obtained from the respiratory care unit in Al-Diwanyiah Teaching Hospital \Diwanyah, Iraq, from the first of November 2024 to the first of March 2025. The bacteria were identified, and antibiotic sensitivity testing was performed using VITEK 2 ID-GN and AST cards. Hypermucoviscosity was assessed using the string test, and an investigation into several adherence and virulence genes was conducted for all isolates. Then, multi-locus sequence typing was performed for hypermucoviscous K. pneumoniae isolates.
Results: 3 (4.22%) of 71 isolates were hypermucoviscous. The virulence and adherence genes were present in 100% of the isolates, whereas rmpA was only found in hypermucoviscous isolates. The results showed that the hmKp isolates were members of clonal group 147 (CG147) and were assigned to sequence type (ST) 293.
Conclusion: The string test is the primary phenotypical diagnosis for hmKp, while the genetically encoded rmpA gene is the most reliable genetic marker for hmKp identification. However, MLST is not beneficial for identification. The central positioning of ST392 within the MST highlights its potential role as an emerging high-risk clone.
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2. Namikawa H, Yamada K, Sakiyama A, Imoto W, Yamairi K, Shibata W, et al. Clinical characteristics of bacteremia caused by hypermucoviscous Klebsiella pneumoniae at a tertiary hospital. Diagn Microbiol Infect Dis 2019; 95: 84-88.
3. Fauvet T, Tarantola A, Colot J, Merlet A, Goarant C, Marot B, et al. Mucoviscous characteristics of Klebsiella pneumoniae strains: A factor of clinical severity? Med Mal Infect 2020; 50: 500-506.
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11. Makhrmash JH, Al-Aidy SR, Qaddoori BH. Investigation of biofilm virulence gene prevalence in Klebsiella pneumoniae isolated from urinary tract infections. Arch Razi Inst 2022; 77: 1421-1427.
12. Rakotondrasoa A, Passet V, Herindrainy P, Garin B, Kermorvant-Duchemin E, Delarocque-Astagneau E, et al. Characterization of Klebsiella pneumoniae isolates from a mother–child cohort in Madagascar. J Antimicrob Chemother 2020; 75: 1736-1746.
13. Vuotto C, Longo F, Pascolini C, Donelli G, Balice M, Libori M, et al. Biofilm formation and antibiotic resistance in Klebsiella pneumoniae urinary strains. J Appl Microbiol 2017; 123: 1003-1018.
14. Lee H-C, Chuang Y-C, Yu W-L, Lee N-Y, Chang C-M, Ko N-Y, et al. Clinical implications of hypermucoviscosity phenotype in Klebsiella pneumoniae isolates: association with invasive syndrome in patients with community-acquired bacteremia. J Intern Med 2006; 259: 606-614.
15. Bakhtiari R, Javadi A, Aminzadeh M, Molaee-Aghaee E, Shaffaghat Z. Association between presence of RmpA, MrkA, and MrkD genes and antibiotic resistance in clinical Klebsiella pneumoniae isolates from hospitals in Tehran, Iran. Iran J Public Health 2021; 50: 1009-1016.
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17. Diancourt L, Passet V, Verhoef J, Grimont PA, Brisse S. Multilocus sequence typing of Klebsiella pneumoniae nosocomial isolates. J Clin Microbiol 2005; 43: 4178-4182.
18. Catalán-Nájera JC, Garza-Ramos U, Barrios-Camacho H. Hypervirulence and hypermucoviscosity: two different but complementary Klebsiella spp. Phenotypes? Virulence 2017; 8: 1111-1123.
19. Chu WHW, Tan YH, Tan SY, Chen Y, Yong M, Lye DC, et al. Acquisition of regulator on virulence plasmid of hypervirulent Klebsiella allows bacterial lifestyle switch in response to iron. mBio 2023; 14(4): e0129723.
20. Anchez-López J, García-Caballero A, Navarro-San Francisco C, Quereda C, Ruiz-Garbajosa P, Navas E, et al. Hypermucoviscous Klebsiella pneumoniae: A challenge in community-acquired infection. IDCases 2019; 17: e00547.
21. Mahdi Jabir D. Bacterial Infections associated with COVID-19 and the effect of using many common antibiotics in the treatment of these infections. Iran J Med Microbiol 2022; 16: 363-367.
22. Thapa TB, Maharjan S, Giri N, Sapkota M, Shrestha O, Khanal PR, et al. Incidence of hypermucoviscous Klebsiella pneumoniae and phenotypic detection of its virulence factors, along with classical strains, among patients visiting a tertiary care hospital. J Infect Dev Ctries 2025; 19: 258-266.
23. D’Apolito D, Arena F, Conte V, De Angelis LH, Di Mento G, Carreca AP, et al. Phenotypical and molecular assessment of the virulence potential of KPC-3-producing Klebsiella pneumoniae ST392 clinical isolates. Microbiol Res 2020; 240: 126551.
24. Chew KL, Octavia S, Lai D, Lin RTP, Teo JWP. Genomic Characterization of Klebsiella quasipneumoniae from clinical specimens in singapore. Antimicrob Agents Chemother 2021; 65(8): e0041221.
25. Rodrigues C, Desai S, Passet V, Gajjar D, Brisse S. Genomic evolution of the globally disseminated multidrug-resistant Klebsiella pneumoniae clonal group 147. Microb Genom 2022; 8: 000737.
2. Namikawa H, Yamada K, Sakiyama A, Imoto W, Yamairi K, Shibata W, et al. Clinical characteristics of bacteremia caused by hypermucoviscous Klebsiella pneumoniae at a tertiary hospital. Diagn Microbiol Infect Dis 2019; 95: 84-88.
3. Fauvet T, Tarantola A, Colot J, Merlet A, Goarant C, Marot B, et al. Mucoviscous characteristics of Klebsiella pneumoniae strains: A factor of clinical severity? Med Mal Infect 2020; 50: 500-506.
4. Cubero M, Grau I, Tubau F, Pallarés R, Dominguez MA, Liñares J, et al. Hypervirulent Klebsiella pneumoniae clones causing bacteraemia in adults in a teaching hospital in Barcelona, Spain (2007–2013). Clin Microbiol Infect 2016; 22: 154-160.
5. Tan TY, Ong M, Cheng Y, Ng LSY. Hypermucoviscosity, rmpA, and aerobactin are associated with community-acquired Klebsiella pneumoniae bacteremic isolates causing liver abscess in Singapore. J Microbiol Immunol Infect 2019; 52: 30-34.
6. Fung C-P, Chang F-Y, Lin J-C, Ho DM-T, Chen C-T, Chen J-H, et al. Immune response and pathophysiological features of Klebsiella pneumoniae liver abscesses in an animal model. Lab Invest 2011; 91: 1029-1039.
7. Ballén V, Gabasa Y, Ratia C, Ortega R, Tejero M, Soto S. Antibiotic resistance and virulence profiles of Klebsiella pneumoniae strains isolated from different clinical sources. Front Cell Infect Microbiol 2021; 11: 738223.
8. Hu Y-L, Bi S-L, Zhang Z-Y, Kong N-Q. Correlation between antibiotic resistance, virulence genes, and genotypes among Klebsiella pneumoniae clinical strains isolated in Guangzhou, China. Curr Microbiol 2024; 81: 289.
9. Li N, Wang L, Wang F, Chen H, Tao S, Zhu Q, et al. Rapid detection of Klebsiella pneumoniae carrying virulence gene rmpA2 by Recombinase polymerase Amplification Combined with Lateral flow strips. Front Cell Infect Microbiol 2022; 12: 877649.
10. Morreale DP, St Geme Iii JW, Planet PJ. Phylogenomic analysis of the understudied Neisseriaceae species reveals a poly-and paraphyletic Kingella genus. Microbiol Spectr 2023; 11(6): e0312323.
11. Makhrmash JH, Al-Aidy SR, Qaddoori BH. Investigation of biofilm virulence gene prevalence in Klebsiella pneumoniae isolated from urinary tract infections. Arch Razi Inst 2022; 77: 1421-1427.
12. Rakotondrasoa A, Passet V, Herindrainy P, Garin B, Kermorvant-Duchemin E, Delarocque-Astagneau E, et al. Characterization of Klebsiella pneumoniae isolates from a mother–child cohort in Madagascar. J Antimicrob Chemother 2020; 75: 1736-1746.
13. Vuotto C, Longo F, Pascolini C, Donelli G, Balice M, Libori M, et al. Biofilm formation and antibiotic resistance in Klebsiella pneumoniae urinary strains. J Appl Microbiol 2017; 123: 1003-1018.
14. Lee H-C, Chuang Y-C, Yu W-L, Lee N-Y, Chang C-M, Ko N-Y, et al. Clinical implications of hypermucoviscosity phenotype in Klebsiella pneumoniae isolates: association with invasive syndrome in patients with community-acquired bacteremia. J Intern Med 2006; 259: 606-614.
15. Bakhtiari R, Javadi A, Aminzadeh M, Molaee-Aghaee E, Shaffaghat Z. Association between presence of RmpA, MrkA, and MrkD genes and antibiotic resistance in clinical Klebsiella pneumoniae isolates from hospitals in Tehran, Iran. Iran J Public Health 2021; 50: 1009-1016.
16. Gupta V, Garg R, Kumaraswamy K, Datta P, Mohi GK, Chander J. Phenotypic and genotypic characterization of carbapenem resistance mechanisms in Klebsiella pneumoniae from blood culture specimens: A study from North India. J Lab Physicians 2018; 10: 125-129.
17. Diancourt L, Passet V, Verhoef J, Grimont PA, Brisse S. Multilocus sequence typing of Klebsiella pneumoniae nosocomial isolates. J Clin Microbiol 2005; 43: 4178-4182.
18. Catalán-Nájera JC, Garza-Ramos U, Barrios-Camacho H. Hypervirulence and hypermucoviscosity: two different but complementary Klebsiella spp. Phenotypes? Virulence 2017; 8: 1111-1123.
19. Chu WHW, Tan YH, Tan SY, Chen Y, Yong M, Lye DC, et al. Acquisition of regulator on virulence plasmid of hypervirulent Klebsiella allows bacterial lifestyle switch in response to iron. mBio 2023; 14(4): e0129723.
20. Anchez-López J, García-Caballero A, Navarro-San Francisco C, Quereda C, Ruiz-Garbajosa P, Navas E, et al. Hypermucoviscous Klebsiella pneumoniae: A challenge in community-acquired infection. IDCases 2019; 17: e00547.
21. Mahdi Jabir D. Bacterial Infections associated with COVID-19 and the effect of using many common antibiotics in the treatment of these infections. Iran J Med Microbiol 2022; 16: 363-367.
22. Thapa TB, Maharjan S, Giri N, Sapkota M, Shrestha O, Khanal PR, et al. Incidence of hypermucoviscous Klebsiella pneumoniae and phenotypic detection of its virulence factors, along with classical strains, among patients visiting a tertiary care hospital. J Infect Dev Ctries 2025; 19: 258-266.
23. D’Apolito D, Arena F, Conte V, De Angelis LH, Di Mento G, Carreca AP, et al. Phenotypical and molecular assessment of the virulence potential of KPC-3-producing Klebsiella pneumoniae ST392 clinical isolates. Microbiol Res 2020; 240: 126551.
24. Chew KL, Octavia S, Lai D, Lin RTP, Teo JWP. Genomic Characterization of Klebsiella quasipneumoniae from clinical specimens in singapore. Antimicrob Agents Chemother 2021; 65(8): e0041221.
25. Rodrigues C, Desai S, Passet V, Gajjar D, Brisse S. Genomic evolution of the globally disseminated multidrug-resistant Klebsiella pneumoniae clonal group 147. Microb Genom 2022; 8: 000737.
| Files | ||
| Issue | Vol 17 No 5 (2025) | |
| Section | Original Article(s) | |
| DOI | https://doi.org/10.18502/ijm.v17i5.19882 | |
| Keywords | ||
| Klebsiella pneumonia Hypermucoviscosity Bacterial capsules rmpA gene Virulence | ||
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
How to Cite
1.
Ali H, Jabir D, Falih Z, Najm S. Phenotypic and genotypic analysis of hypermucoviscous Klebsiella pneumoniae (hmkp) strain. Iran J Microbiol. 2025;17(5):734-740.
