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Nonne F, Molfetta M, Nappini R, La Guidara C, Di Benedetto R, Mfana S, Bellich B, Raso MM, Gasperini G, Alfini R, Cescutti P, Berlanda Scorza F, Ravenscroft N, Micoli F, Giannelli C. Development and Application of a High-Throughput Method for the Purification and Analysis of Surface Carbohydrates from Klebsiella pneumoniae. BIOLOGY 2024; 13:256. [PMID: 38666868 PMCID: PMC11048683 DOI: 10.3390/biology13040256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024]
Abstract
Klebsiella pneumoniae (Kp) is a Gram-negative bacterium, and a leading cause of neonatal sepsis in low- and middle-income countries, often associated with anti-microbial resistance. Two types of polysaccharides are expressed on the Kp cell surface and have been proposed as key antigens for vaccine design: capsular polysaccharides (known as K-antigens, K-Ags) and O-antigens (O-Ags). Historically, Kp has been classified using capsule serotyping and although 186 distinct genotypes have been predicted so far based on sequence analysis, many structures are still unknown. In contrast, only 11 distinct OAg serotypes have been described. The characterization of emerging strains requires the development of a high-throughput purification method to obtain sufficient K- and O-Ag material to characterize the large collection of serotypes and gain insight on structural features and potential cross-reactivity that could allow vaccine simplification. Here, this was achieved by adapting our established method for the simple purification of O-Ags, using mild acetic acid hydrolysis performed directly on bacterial cells, followed by filtration and precipitation steps. The method was successfully applied to purify the surface carbohydrates from different Kp strains, thereby demonstrating the robustness and general applicability of the purification method developed. Further, antigen characterization showed that the purification method had no impact on the structural integrity of the polysaccharides and preserved labile substituents such as O-acetyl and pyruvyl groups. This method can be further optimized for scaling up and manufacturing to support the development of high-valency saccharide-based vaccines against Kp.
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Affiliation(s)
- Francesca Nonne
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Mariagrazia Molfetta
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Rebecca Nappini
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
- Department of Life Science, University of Trieste, 34127 Trieste, Italy;
| | - Chiara La Guidara
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Roberta Di Benedetto
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Siwaphiwe Mfana
- Department of Chemistry, University of Cape Town, Cape Town 7700, South Africa; (S.M.); (N.R.)
| | - Barbara Bellich
- Department of Advanced Translational Diagnostics, Institute for Maternal and Child Health, IRCCS “Burlo Garofolo”, 34137 Trieste, Italy;
| | - Maria Michelina Raso
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | | | - Renzo Alfini
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Paola Cescutti
- Department of Life Science, University of Trieste, 34127 Trieste, Italy;
| | - Francesco Berlanda Scorza
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Neil Ravenscroft
- Department of Chemistry, University of Cape Town, Cape Town 7700, South Africa; (S.M.); (N.R.)
| | - Francesca Micoli
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
| | - Carlo Giannelli
- GSK Vaccines Institute for Global Health, 53100 Siena, Italy; (M.M.); (R.N.); (C.L.G.); (R.D.B.); (M.M.R.); (R.A.); (F.B.S.); (F.M.); (C.G.)
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Noreika A, Stankevičiūtė J, Rutkienė R, Meškys R, Kalinienė L. Exploring the enzymatic activity of depolymerase gp531 from Klebsiella pneumoniae jumbo phage RaK2. Virus Res 2023; 336:199225. [PMID: 37741345 PMCID: PMC10550766 DOI: 10.1016/j.virusres.2023.199225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/28/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Klebsiella pneumoniae poses a major global challenge due to its virulence, multidrug resistance, and nosocomial nature. Thus, bacteriophage-derived proteins are extensively being investigated as a means to combat this bacterium. In this study, we explored the enzymatic specificity of depolymerase gp531, encoded by the jumbo bacteriophage vB_KleM_RaK2 (RaK2). We used two different methods to modify the reducing end of the oligosaccharides released during capsule hydrolysis with gp531. Subsequent acidic cleavage with TFA, followed by TLC and HPLC-MS analyses, revealed that RaK2 gp531 is a β-(1→4)-endoglucosidase. The enzyme specifically recognizes and cleaves the capsular polysaccharide (CPS) of the Klebsiella pneumoniae K54 serotype, releasing K-unit monomers (the main product), dimers, and trimers. Depolymerase gp531 remains active from 10 to 50 °C and in the pH 3-8 range, indicating its stability and versatility. Additionally, we demonstrated that gp531's activity is not affected by CPS acetylation, which is influenced by the growth conditions of the bacterial culture. Overall, our findings provide valuable insights into the enzymatic activity of the first characterized depolymerase targeting the capsule of the clinically relevant K54 serotype of K. pneumoniae.
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Affiliation(s)
- Algirdas Noreika
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania.
| | - Jonita Stankevičiūtė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania
| | - Rasa Rutkienė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania
| | - Rolandas Meškys
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania
| | - Laura Kalinienė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius, Lithuania.
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Luo C, Chen Y, Hu X, Chen S, Lin Y, Liu X, Yang B. Genetic and Functional Analysis of the pks Gene in Clinical Klebsiella pneumoniae Isolates. Microbiol Spectr 2023; 11:e0017423. [PMID: 37341601 PMCID: PMC10433862 DOI: 10.1128/spectrum.00174-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/12/2023] [Indexed: 06/22/2023] Open
Abstract
The pks gene cluster encodes colibactin, which can cause DNA damage and enhance the virulence in Escherichia coli. However, the role of the pks gene in Klebsiella pneumoniae has not been fully discussed. The aim of this study was to analyze the relationship between the pks gene cluster and virulence factors, as well as to assess antibiotic resistance and biofilm formation capacity in clinical isolates of Klebsiella pneumoniae. Thirty-eight of 95 clinical K. pneumoniae strains were pks positive. pks-positive strains usually infected emergency department patients, and pks-negative strains often infected hospitalized patients. The positive rates of K1 capsular serotype and hypervirulence genes (peg-344, rmpA, rmpA2, iucA, and iroB) were significantly higher in the pks-positive isolates than the pks-negative isolates (P < 0.05). The biofilm formation ability of pks-positive isolates was stronger than that of pks-negative isolates. Antibacterial drug susceptibility test showed the resistance of pks-positive isolates was weaker than that of pks-negative isolates. In conclusion, patients with pks-positive K. pneumoniae infection might have worse treatment outcomes and prognosis. pks-positive K. pneumoniae might have stronger virulence and pathogenicity. Clinical infection with pks-positive K. pneumoniae needs further attention. IMPORTANCE The infection rate with pks-positive K. pneumoniae has been increasing in recent years. Two previous surveys in Taiwan reported 25.6% pks gene islands and 16.7% pks-positive K. pneumoniae strains in bloodstream infections, and Chinese scholars also did a survey of K. pneumoniae bloodstream infections in Changsha, China, and found 26.8% pks-positive K. pneumoniae. In addition, it was found that the pks gene cluster might encode colibactin, which could be related to the virulence of K. pneumoniae. Studies confirmed that the prevalence of colibactin-producing K. pneumoniae was increasing. It is necessary to consider the clear relationship between the pks gene cluster and high pathogenicity in K. pneumoniae.
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Affiliation(s)
- Chenshuo Luo
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Department of Laboratory Medicine, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Yanshu Chen
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Xueni Hu
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Shanjian Chen
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Fujian Key Laboratory of Laboratory Medicine, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Yulan Lin
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Department of Laboratory Medicine, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Fujian Key Laboratory of Laboratory Medicine, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Xiaoqian Liu
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Bin Yang
- Department of Laboratory Medicine, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Department of Laboratory Medicine, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Fujian Key Laboratory of Laboratory Medicine, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Gene Diagnosis Research Center, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
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Del Rio A, Muresu N, Sotgiu G, Saderi L, Sechi I, Cossu A, Usai M, Palmieri A, Are BM, Deiana G, Cocuzza C, Martinelli M, Calaresu E, Piana AF. High-Risk Clone of Klebsiella pneumoniae Co-Harbouring Class A and D Carbapenemases in Italy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052623. [PMID: 35270321 PMCID: PMC8909938 DOI: 10.3390/ijerph19052623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022]
Abstract
Background: Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) is endemic globally, causing severe infections in hospitalized patients. Surveillance programs help monitor and promptly identify the emergence of new clones. We reported the rapid spread of a novel clone of K. pneumoniae co-harbouring class A and D carbapenemases in colonized patients, and the potential risk factors involved in the development of infections. Methods: Rectal swabs were used for microbiological analyses and detection of the most common carbapenemase encoding genes by real-time PCR (i.e., blaKPC, blaOXA-48, blaNDM, blaVIM, and blaIMP). All strains co-harbouring KPC and OXA-48 genes were evaluated. For each patient, the following variables were collected: age, sex, length and ward of stay, device use, and outcome. Clonality of CR-Kp was assessed by preliminary pulsed field gel electrophoresis (PFGE), followed by multi-locus sequence typing (MLST) analyses. Results: A total of 127 isolates of K. pneumoniae co-harbouring KPC and OXA-48 were collected between September 2019 and December 2020. The median age (IQR) of patients was 70 (61–77). More than 40% of patients were admitted to intensive care unit (ICU). Around 25% of patients developed an invasive infection, the majority of which were respiratory tract infections (17/31; 54.8%). ICU stay and invasive infection increased the risk of mortality (OR: 5.39, 95% CI: 2.42–12.00; OR 6.12, 95% CI: 2.55–14.69, respectively; p-value ≤ 0.001). The antibiotic susceptibility test showed a resistance profile for almost all antibiotics considered. Monoclonal origin was confirmed by PFGE and MLST showing a similar restriction pattern and belonging to ST-512. Conclusions: We report the spread and the marked antibiotic resistance profiles of K. pneumoniae strains co-producing KPC and OXA-48. Further study could clarify the roles of clinical and microbiological variables in the development of invasive infection and increasing risk of mortality, in colonized patients.
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Affiliation(s)
- Arcadia Del Rio
- Biomedical Science PhD School, Biomedical Science Department, University of Sassari, 07100 Sassari, Italy; (A.D.R.); (G.D.)
| | - Narcisa Muresu
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
| | - Giovanni Sotgiu
- Clinical Epidemiology and Medical Statistics Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy;
- Correspondence: ; Tel.: +39-079-229959
| | - Laura Saderi
- Clinical Epidemiology and Medical Statistics Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy;
| | - Illari Sechi
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
| | - Andrea Cossu
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
| | - Manuela Usai
- Department of Humanistic and Social Sciences, University of Sassari, 07100 Sassari, Italy;
| | - Alessandra Palmieri
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
| | - Bianca Maria Are
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
| | - Giovanna Deiana
- Biomedical Science PhD School, Biomedical Science Department, University of Sassari, 07100 Sassari, Italy; (A.D.R.); (G.D.)
| | - Clementina Cocuzza
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (C.C.); (M.M.); (E.C.)
| | - Marianna Martinelli
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (C.C.); (M.M.); (E.C.)
| | - Enrico Calaresu
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (C.C.); (M.M.); (E.C.)
| | - Andrea Fausto Piana
- Hygiene Unit, Department of Medical, Surgical and Experimental Sciences, University of Sassari, 07100 Sassari, Italy; (N.M.); (I.S.); (A.C.); (A.P.); (B.M.A.); (A.F.P.)
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Structural characteristics of three pectins isolated from white kidney bean. Int J Biol Macromol 2021; 182:2151-2161. [PMID: 34051255 DOI: 10.1016/j.ijbiomac.2021.05.154] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 01/05/2023]
Abstract
Three water-soluble pectic polysaccharides (WKBP-P2, P3 and P4) were isolated from white kidney bean by ion exchange combined with size-exclusion methods. The structural features were characterized by GC-MS, NMR spectroscopy and HPSEC-MALLS-RI. It was found that three pectic polysaccharides were the major water-extracted polysaccharides in white kidney bean. All the WKBP-P2, P3 and P4 were probably composed of various structural regions including homogalacturonan (HG), xylogalacturonan (XGA), rhamnogalacturonan I (RG-I) regions in backbone, and arabinan region mainly as side chain. However, these pectic polysaccharides were significantly different in molar ratios of these structural regions and molecular size. WKBP-P2 was HG-predominant pectin (partially methyl-esterified) with weight-average molecular weight (Mw) of 1.2 × 104 g/mol, and contained minor RG-I, arabinan and probable XGA regions. WKBP-P3 (Mw of 4.0 × 104 g/mol) primarily embraced XGA, HG, arabinan regions and minor RG-I region. WKBP-4 with highest Mw (4.5 × 105 g/mol) had the most arabinan region (51.3%), which was probably the side chain linked to the backbone composed of RG-I, HG and slight XGA regions. These findings provided a structural basis for study on polysaccharides from white kidney bean, which was benefit for development of functional food.
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Henrici De Angelis L, Poerio N, Di Pilato V, De Santis F, Antonelli A, Thaller MC, Fraziano M, Rossolini GM, D’Andrea MM. Phage Resistance Is Associated with Decreased Virulence in KPC-Producing Klebsiella pneumoniae of the Clonal Group 258 Clade II Lineage. Microorganisms 2021; 9:microorganisms9040762. [PMID: 33917365 PMCID: PMC8067426 DOI: 10.3390/microorganisms9040762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 11/16/2022] Open
Abstract
Phage therapy is now reconsidered with interest in the treatment of bacterial infections. A major piece of information for this application is the definition of the molecular targets exploited by phages to infect bacteria. Here, the genetic basis of resistance to the lytic phage φBO1E by its susceptible host Klebsiella pneumoniae KKBO-1 has been investigated. KKBO-1 phage-resistant mutants were obtained by infection at high multiplicity. One mutant, designated BO-FR-1, was selected for subsequent experiments, including virulence assessment in a Galleria mellonella infection model and characterization by whole-genome sequencing. Infection with BO-FR-1 was associated with a significantly lower mortality when compared to that of the parental strain. The BO-FR-1 genome differed from KKBO-1 by a single nonsense mutation into the wbaP gene, which encodes a glycosyltransferase involved in the first step of the biosynthesis of the capsular polysaccharide (CPS). Phage susceptibility was restored when BO-FR-1 was complemented with the constitutive wbaP gene. Our results demonstrated that φBO1E infects KKBO-1 targeting the bacterial CPS. Interestingly, BO-FR-1 was less virulent than the parental strain, suggesting that in the context of the interplay among phage, bacterial pathogen and host, the emergence of phage resistance may be beneficial for the host.
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Affiliation(s)
- Lucia Henrici De Angelis
- Department of Medical Biotechnologies, University of Siena, Viale Mario Bracci, 16, 53100 Siena, Italy;
| | - Noemi Poerio
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica snc, 00133 Rome, Italy; (N.P.); (F.D.S.); (M.C.T.); (M.F.)
| | - Vincenzo Di Pilato
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Via Benedetto XV, 6, 16126 Genoa, Italy;
| | - Federica De Santis
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica snc, 00133 Rome, Italy; (N.P.); (F.D.S.); (M.C.T.); (M.F.)
| | - Alberto Antonelli
- Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50121 Florence, Italy; (A.A.); (G.M.R.)
- Microbiology and Virology Unit, Florence Careggi University Hospital, Largo Brambilla, 3, 50121 Florence, Italy
| | - Maria Cristina Thaller
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica snc, 00133 Rome, Italy; (N.P.); (F.D.S.); (M.C.T.); (M.F.)
| | - Maurizio Fraziano
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica snc, 00133 Rome, Italy; (N.P.); (F.D.S.); (M.C.T.); (M.F.)
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50121 Florence, Italy; (A.A.); (G.M.R.)
- Microbiology and Virology Unit, Florence Careggi University Hospital, Largo Brambilla, 3, 50121 Florence, Italy
| | - Marco Maria D’Andrea
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica snc, 00133 Rome, Italy; (N.P.); (F.D.S.); (M.C.T.); (M.F.)
- Correspondence:
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Domingo-Calap P, Beamud B, Mora-Quilis L, González-Candelas F, Sanjuán R. Isolation and Characterization of Two Klebsiella pneumoniae Phages Encoding Divergent Depolymerases. Int J Mol Sci 2020; 21:E3160. [PMID: 32365770 PMCID: PMC7246685 DOI: 10.3390/ijms21093160] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 01/05/2023] Open
Abstract
The emergence of multidrug-resistant bacteria is a major global health concern. The search for new therapies has brought bacteriophages into the spotlight, and new phages are being described as possible therapeutic agents. Among the bacteria that are most extensively resistant to current antibiotics is Klebsiella pneumoniae, whose hypervariable extracellular capsule makes treatment particularly difficult. Here, we describe two new K. pneumoniae phages, πVLC5 and πVLC6, isolated from environmental samples. These phages belong to the genus Drulisvirus within the family Podoviridae. Both phages encode a similar tail spike protein with putative depolymerase activity, which is shared among other related phages and probably determines their ability to specifically infect K. pneumoniae capsular types K22 and K37. In addition, we found that phage πVLC6 also infects capsular type K13 and is capable of striping the capsules of K. pneumoniae KL2 and KL3, although the phage was not infectious in these two strains. Genome sequence analysis suggested that the extended tropism of phage πVLC6 is conferred by a second, divergent depolymerase. Phage πVLC5 encodes yet another putative depolymerase, but we found no activity of this phage against capsular types other than K22 and K37, after testing a panel of 77 reference strains. Overall, our results confirm that most phages productively infected one or few Klebsiella capsular types. This constitutes an important challenge for clinical applications.
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Affiliation(s)
- Pilar Domingo-Calap
- Institute for Integrative Systems Biology, ISysBio, Universitat de València-CSIC, 46980 Paterna, Spain; (L.M.-Q.); (F.G.-C.); (R.S.)
- Department of Genetics, Universitat de València, 46980 Paterna, Spain
| | - Beatriz Beamud
- FISABIO-Salud Pública, Generalitat Valenciana, 46020 Valencia, Spain;
| | - Lucas Mora-Quilis
- Institute for Integrative Systems Biology, ISysBio, Universitat de València-CSIC, 46980 Paterna, Spain; (L.M.-Q.); (F.G.-C.); (R.S.)
| | - Fernando González-Candelas
- Institute for Integrative Systems Biology, ISysBio, Universitat de València-CSIC, 46980 Paterna, Spain; (L.M.-Q.); (F.G.-C.); (R.S.)
- FISABIO-Salud Pública, Generalitat Valenciana, 46020 Valencia, Spain;
- CIBER in Epidemiology and Public Health, 46020 Valencia, Spain
| | - Rafael Sanjuán
- Institute for Integrative Systems Biology, ISysBio, Universitat de València-CSIC, 46980 Paterna, Spain; (L.M.-Q.); (F.G.-C.); (R.S.)
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