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Ziller L, Blum PC, Buhl EM, Krüttgen A, Horz HP, Tagliaferri TL. Newly isolated Drexlerviridae phage LAPAZ is physically robust and fosters eradication of Klebsiella pneumoniae in combination with meropenem. Virus Res 2024; 347:199417. [PMID: 38880333 DOI: 10.1016/j.virusres.2024.199417] [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: 12/19/2023] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
Due to the spread of multidrug resistance there is a renewed interest in using bacteriophages (briefly: phages) for controlling bacterial pathogens. The objective of this study was the characterization of a newly isolated phage (i.e. phage LAPAZ, vB_KpnD-LAPAZ), its antimicrobial activity against multidrug resistant Klebsiella pneumoniae and potential synergistic interactions with antibiotics. LAPAZ belongs to the family Drexlerviridae (genus: Webervirus) and lysed 30 % of tested strains, whereby four distinct capsular types can be infected. The genome consists of 51,689 bp and encodes 84 ORFs. The latent period is 30 min with an average burst size of 27 PFU/cell. Long-term storage experiments show that LAPAZ is significantly more stable in wastewater compared to laboratory media. A phage titre of 90 % persists up to 30 min at 50 ˚C and entire phage loss was seen only at temperatures > 66 ˚C. Besides stability against UV-C, antibacterial activity in liquid culture medium was consistent at pH values ranging from 4 to 10. Unlike exposure to phage or antibiotic alone, synergistic interactions and a complete bacterial eradication was achieved when combining LAPAZ with meropenem. In addition, synergism with the co-presence of ciprofloxacin was observed and phage resistance emergence could be delayed. Without co-addition of the antibiotic, phage resistant mutants readily emerged and showed a mixed pattern of drug sensitivity alterations. Around 88 % became less sensitive towards ceftazidime, meropenem and gentamicin. Conversely, around 44 % showed decreased resistance levels against ciprofloxacin. Whole genome analysis of a phage-resistant mutant with a 16-fold increased sensitivity towards ciprofloxacin revealed one de novo frameshift mutation leading to a gene fusion affecting two transport proteins belonging to the major facilitator-superfamily (MFS). Apparently, this mutation compromises ciprofloxacin efflux efficiency and further studies are warranted to understand how the non-mutated protein might be involved in phage-host adsorption.
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Affiliation(s)
- Leonie Ziller
- Institute of Medical Microbiology, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | | | - Eva Miriam Buhl
- Electron Microscopy Facility, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Alex Krüttgen
- Laboratory Diagnostic Center, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Hans-Peter Horz
- Institute of Medical Microbiology, RWTH Aachen University Hospital, 52074 Aachen, Germany.
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Wahl A, Fischer MA, Klaper K, Müller A, Borgmann S, Friesen J, Hunfeld KP, Ilmberger A, Kolbe-Busch S, Kresken M, Lippmann N, Lübbert C, Marschner M, Neumann B, Pfennigwerth N, Probst-Kepper M, Rödel J, Schulze MH, Zautner AE, Werner G, Pfeifer Y. Presence of hypervirulence-associated determinants in Klebsiella pneumoniae from hospitalised patients in Germany. Int J Med Microbiol 2024; 314:151601. [PMID: 38359735 DOI: 10.1016/j.ijmm.2024.151601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/15/2023] [Accepted: 01/15/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Klebsiella (K.) pneumoniae is a ubiquitous Gram-negative bacterium and a common coloniser of animals and humans. Today, K. pneumoniae is one of the most persistent nosocomial pathogens worldwide and poses a severe threat/burden to public health by causing urinary tract infections, pneumonia and bloodstream infections. Infections mainly affect immunocompromised individuals and hospitalised patients. In recent years, a new type of K. pneumoniae has emerged associated with community-acquired infections such as pyogenic liver abscess in otherwise healthy individuals and is therefore termed hypervirulent K. pneumoniae (hvKp). The aim of this study was the characterisation of K. pneumoniae isolates with properties of hypervirulence from Germany. METHODS A set of 62 potentially hypervirulent K. pneumoniae isolates from human patients was compiled. Inclusion criteria were the presence of at least one determinant that has been previously associated with hypervirulence: (I) clinical manifestation, (II) a positive string test as a marker for hypermucoviscosity, and (III) presence of virulence associated genes rmpA and/or rmpA2 and/or magA. Phenotypic characterisation of the isolates included antimicrobial resistance testing by broth microdilution. Whole genome sequencing (WGS) was performed using Illumina® MiSeq/NextSeq to investigate the genetic repertoire such as multi-locus sequence types (ST), capsule types (K), further virulence associated genes and resistance genes of the collected isolates. For selected isolates long-read sequencing was applied and plasmid sequences with resistance and virulence determinants were compared. RESULTS WGS analyses confirmed presence of several signature genes for hvKp. Among them, the most prevalent were the siderophore loci iuc and ybt and the capsule regulator genes rmpA and rmpA2. The most dominant ST among the hvKp isolates were ST395 capsule type K2 and ST395 capsule type K5; both have been described previously and were confirmed by our data as multidrug-resistant (MDR) isolates. ST23 capsule type K1 was the second most abundant ST in this study; this ST has been described as commonly associated with hypervirulence. In general, resistance to beta-lactams caused by the production of extended-spectrum beta-lactamases (ESBL) and carbapenemases was observed frequently in our isolates, confirming the threatening rise of MDR-hvKp strains. CONCLUSIONS Our study results show that K. pneumoniae strains that carry several determinants of hypervirulence are present for many years in Germany. The detection of carbapenemase genes and hypervirulence associated genes on the same plasmid is highly problematic and requires intensified screening and molecular surveillance. However, the non-uniform definition of hvKp complicates their detection. Testing for hypermucoviscosity alone is not specific enough to identify hvKp. Thus, we suggest that the classification of hvKp should be applied to isolates that not only fulfil phenotypical criteria (severe clinical manifestations, hypermucoviscosity) but also (I) the presence of at least two virulence loci e.g. iuc and ybt, and (II) the presence of rmpA and/or rmpA2.
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Affiliation(s)
- Anika Wahl
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Martin A Fischer
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Kathleen Klaper
- Robert Koch Institute, Department of Sexually transmitted bacterial Pathogens (STI) and HIV, Berlin, Germany
| | - Annelie Müller
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Stefan Borgmann
- Klinikum Ingolstadt, Department of Infectious Diseases and Infection Control, Ingolstadt, Germany
| | | | - Klaus-Peter Hunfeld
- Institute for Laboratory Medicine, Microbiology & Infection Control, Northwest Medical Centre, Medical Faculty, Goethe University, Frankfurt am Main, Germany
| | | | - Susanne Kolbe-Busch
- Institute of Hygiene, Hospital Epidemiology and Environmental Medicine, Leipzig University Medical Center, Leipzig, Germany; Interdisciplinary Center for Infectious Diseases, Leipzig University Medical Center, Leipzig, Germany
| | - Michael Kresken
- Paul-Ehrlich-Gesellschaft für Infektionstherapie e. V., Cologne, Germany
| | - Norman Lippmann
- Institute for Medical Microbiology and Virology, University Hospital of Leipzig, Leipzig, Germany
| | - Christoph Lübbert
- Interdisciplinary Center for Infectious Diseases, Leipzig University Medical Center, Leipzig, Germany; Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Leipzig University Medical Center, Leipzig, Germany
| | | | - Bernd Neumann
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Niels Pfennigwerth
- German National Reference Centre for Multidrug-Resistant Gram-Negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany
| | | | - Jürgen Rödel
- Institute of Medical Microbiology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Marco H Schulze
- Department for Infection Control and Infectious Diseases, University Medical Center Goettingen, Goettingen, Germany
| | - Andreas E Zautner
- Institute of Medical Microbiology and Hospital Hygiene, Faculty of Medicine, Otto-von-Guericke-University, Magdeburg, Germany; Center for Health and Medical Prevention (CHaMP), Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Guido Werner
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Yvonne Pfeifer
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany.
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Neumann B, Stürhof C, Rath A, Kieninger B, Eger E, Müller JU, von Poblocki A, Gerlitz N, Wollschläger P, Schneider-Brachert W, Schaufler K, Klaper K, Steinmann J. Detection and characterization of putative hypervirulent Klebsiella pneumoniae isolates in microbiological diagnostics. Sci Rep 2023; 13:19025. [PMID: 37923898 PMCID: PMC10624845 DOI: 10.1038/s41598-023-46221-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023] Open
Abstract
Hypervirulent Klebsiella pneumoniae strains (hvKp) can cause invasive community-acquired infections in healthy patients of all ages. In this study, the prevalence of putative hvKp in a German tertiary center was investigated and hvKp were characterized by phenotypic and molecular assays. All K. pneumoniae isolates in routine microbiological diagnostics from a single center were screened by string-testing over a period of 6 months. String-test positive (≥ 0.5 mm) isolates were re-evaluated on different media and under various conditions (aerobe, anaerobe). For string-test positive isolates, genes (magA, iutA, rmpA and rmpA2) associated with hypermucoviscosity and hypervirulence were amplified by multiplex PCR. PCR-positive isolates were subjected to whole-genome sequencing and sedimentation and biofilm formation assays. From 1310 screened K. pneumoniae isolates in clinical routine 100 isolates (7.6%) were string test positive. From these, 9% (n = 9) were defined as putative hvKp (string-test+/PCR+). Highest rate of string-test-positive isolates was observed on MacConkey agar under aerobic conditions. Amongst these nine putative hvKp isolates, the international lineage ST23 carrying hvKp-plasmid pKpVP-1 was the most common, but also a rare ST86 with pKpVP-2 was identified. All nine isolates showed hypermucoviscosity and weak biofilm formation. In conclusion, 9% of string-positive, respectively 0.69% of all K. pneumoniae isolates from routine were defined as putative hypervirulent. MacConkey agar was the best medium for hvKp screening.
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Affiliation(s)
- Bernd Neumann
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany.
- Institute of Hospital Hygiene, Medical Microbiology and Infectious Diseases, Paracelsus Medical University, Nuremberg General Hospital, Prof.-Ernst-Nathan-Str. 1, 90419, Nuremberg, Germany.
| | - Claudia Stürhof
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Anca Rath
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - Bärbel Kieninger
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - Elias Eger
- Department of Epidemiology and Ecology of Antimicrobial Resistance, Helmholtz Institute for One Health, Helmholtz Centre for Infection Research HZI, Greifswald, Germany
| | - Justus U Müller
- Pharmaceutical Microbiology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Alexander von Poblocki
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Nadja Gerlitz
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Paul Wollschläger
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Wulf Schneider-Brachert
- Department of Infection Prevention and Infectious Diseases, University Hospital Regensburg, Regensburg, Germany
| | - Katharina Schaufler
- Department of Epidemiology and Ecology of Antimicrobial Resistance, Helmholtz Institute for One Health, Helmholtz Centre for Infection Research HZI, Greifswald, Germany
- Pharmaceutical Microbiology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Kathleen Klaper
- Division 18-Sexually transmitted bacterial Pathogens and HIV, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Jörg Steinmann
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
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Pertics BZ, Kovács T, Schneider G. Characterization of a Lytic Bacteriophage and Demonstration of Its Combined Lytic Effect with a K2 Depolymerase on the Hypervirulent Klebsiella pneumoniae Strain 52145. Microorganisms 2023; 11:microorganisms11030669. [PMID: 36985241 PMCID: PMC10051899 DOI: 10.3390/microorganisms11030669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Klebsiella pneumoniae is a nosocomial pathogen. Among its virulence factors is the capsule with a prominent role in defense and biofilm formation. Bacteriophages (phages) can evoke the lysis of bacterial cells. Due to the mode of action of their polysaccharide depolymerase enzymes, phages are typically specific for one bacterial strain and its capsule type. In this study, we characterized a bacteriophage against the capsule-defective mutant of the nosocomial K. pneumoniae 52145 strain, which lacks K2 capsule. The phage showed a relatively narrow host range but evoked lysis on a few strains with capsular serotypes K33, K21, and K24. Phylogenetic analysis showed that the newly isolated Klebsiella phage 731 belongs to the Webervirus genus in the Drexlerviridae family; it has a 31.084 MDa double-stranded, linear DNA with a length of 50,306 base pairs and a G + C content of 50.9%. Out of the 79 open reading frames (ORFs), we performed the identification of orf22, coding for a trimeric tail fiber protein with putative capsule depolymerase activity, along with the mapping of other putative depolymerases of phage 731 and homologous phages. Efficacy of a previously described recombinant K2 depolymerase (B1dep) was tested by co-spotting phage 731 on K. pneumoniae strains, and it was demonstrated that the B1dep-phage 731 combination allows the lysis of the wild type 52145 strain, originally resistant to the phage 731. With phage 731, we showed that B1dep is a promising candidate for use as a possible antimicrobial agent, as it renders the virulent strain defenseless against other phages. Phage 731 alone is also important due to its efficacy on K. pneumoniae strains possessing epidemiologically important serotypes.
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Affiliation(s)
- Botond Zsombor Pertics
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Szigeti St. 12., H-7624 Pécs, Hungary
| | - Tamás Kovács
- Department of Biotechnology, Nanophagetherapy Center, Enviroinvest Corporation, Kertváros St. 2., H-7632 Pécs, Hungary
| | - György Schneider
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Szigeti St. 12., H-7624 Pécs, Hungary
- Correspondence: ; Tel.: +36-72-536-200 (ext. 1908)
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Brennan C, DeLappe N, Cormican M, Tuohy A, Tobin A, Moran L, Doyle M, Fielding C. A geographic cluster of healthcare-associated carbapenemase-producing hypervirulent Klebsiella pneumoniae sequence type 23. Eur J Clin Microbiol Infect Dis 2022:10.1007/s10096-022-04535-z. [PMID: 36454389 DOI: 10.1007/s10096-022-04535-z] [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: 09/21/2022] [Accepted: 11/24/2022] [Indexed: 12/02/2022]
Abstract
Hypervirulent Klebsiella pneumoniae has typically been associated with invasive, community-associated infections. This study describes the molecular, epidemiological and clinical characteristics of a cluster of carbapenemase-producing hypervirulent K. pneumoniae in the South-East of Ireland. It highlights the increasing risk that hypervirulent K. pneumoniae poses to healthcare and residential care populations. A retrospective analysis of sequences on K. pneumoniae isolates in the K. pneumoniae database of the National Carbapenemase-Producing Enterobacterales Reference Laboratory Service was performed to identify cases of hypervirulent K. pneumoniae from one hospital network. Hypervirulence scores were assigned based on the presence of recognised hypervirulence genes. A retrospective review of patient records was carried out for all confirmed cases of hypervirulent K. pneumoniae identified and clinical, epidemiological and molecular characteristics described. Twenty-eight cases of hypervirulent OXA-48 producing K. pneumoniae were identified over a 2-year period. All isolates were sequence-type 23 with a hypervirulence score of 5. All isolates carried the blaOXA-48 carbapenemase gene. All cases had a record of current or recent hospitalisation or residence in a long-term residential care facility. This study describes extensive dissemination of hypervirulent K. pneumoniae within healthcare facilities and an ongoing outbreak in our region. It shows the convergence of hypervirulence and antibiotic resistance determinants. Healthcare facilities need to consider their infection prevention, control and surveillance strategies to monitor and prevent further dissemination among a vulnerable population. Diagnostic laboratories need to ensure they have the ability and capacity for testing. Readily deployed laboratory methods for detection of hypervirulence are required.
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Affiliation(s)
- Caoimhe Brennan
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland.
| | - Niall DeLappe
- National Carbapenemase-Producing Enterobacterales Reference Laboratory, Department of Medical Microbiology, University Hospital Galway, Galway, Ireland
| | - Martin Cormican
- National Carbapenemase-Producing Enterobacterales Reference Laboratory, Department of Medical Microbiology, University Hospital Galway, Galway, Ireland
| | - Alma Tuohy
- National Carbapenemase-Producing Enterobacterales Reference Laboratory, Department of Medical Microbiology, University Hospital Galway, Galway, Ireland
| | - Aideen Tobin
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland
| | - Laura Moran
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland
| | - Maeve Doyle
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland
| | - Caroline Fielding
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland
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6
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Kamau E, Ranson EL, Tsan AT, Bergmann-Leitner ES, Garner OB, Yang S. Clinical and genomic characterization of hypervirulent Klebsiella pneumoniae (hvKp) infections via passive surveillance in Southern California, 2020–2022. Front Microbiol 2022; 13:1001169. [PMID: 36312975 PMCID: PMC9614223 DOI: 10.3389/fmicb.2022.1001169] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Hypervirulent Klebsiella pneumoniae (hvKp) is more invasive and virulent than classical K. pneumoniae, and requires specialized treatment. To raise clinical awareness, this study determined the prevalence, clinical characteristics, and genomic epidemiology of hvKp infections in Southern California (SoCal) by conducting a passive surveillance in a single large academic medical center. We report here that hvKp infections were more common than expected, accounting for 2.6% of invasive K. pneumoniae infections, and presented with a wide disease spectrum, occasionally mimicking tumors, even co-infecting a COVID-19 patient. Most infections were community acquired with no recent international travel, suggesting hvKp strains are circulating in the community. Genomic analysis revealed genetic diversity, with the K1-ST23 lineage predominating but not clonal, and multiple sequence types of K2 including a SoCal unique K2-ST66 sublineage that had been unrecognized. Our findings highlight the urgency of heightened awareness of hvKp infection in the US, the need for rapid diagnosis of hvKp, and the necessity of implementing robust surveillance programs for hvKp at the institutional or local level.
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Affiliation(s)
- Edwin Kamau
- Department of Pathology and Laboratory Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Elizabeth L. Ranson
- Division of Infectious Diseases, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Allison T. Tsan
- Department of Pathology and Laboratory Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Elke S. Bergmann-Leitner
- Biologics Research and Development, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Omai B. Garner
- Department of Pathology and Laboratory Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Shangxin Yang
- Department of Pathology and Laboratory Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
- *Correspondence: Shangxin Yang
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7
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Yang X, Liu X, Xu Y, Yang C, Chan EWC, Shum HP, Chen S. Genetic and Functional Characterization of a Conjugative KpVP-2-Type Virulence Plasmid From a Clinical Klebsiella pneumoniae Strain. Front Microbiol 2022; 13:914884. [PMID: 35935210 PMCID: PMC9354667 DOI: 10.3389/fmicb.2022.914884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/23/2022] [Indexed: 11/23/2022] Open
Abstract
The main mechanism of virulence in Klebsiella pneumoniae is the acquisition of K. pneumoniae virulence plasmids (KpVPs), which include two dominant types, namely, KpVP-1 (carrying iuc1, iro1, rmpA, and rmpA2) and KpVP-2 (carrying iuc2, iro2, and rmpA). Both are non-conjugative and associated with different hypervirulent clones. In contrast to KpVP-1 reported in K1, K2, and other serotypes of K. pneumoniae, KpVP-2 was only reported in K2 strains and rarely characterized. In this study, we identified a conjugative KpVP-2-type virulence plasmid from a clinical hypervirulent K. pneumoniae strain. This plasmid was generated by the integration of conjugative transfer genes into the KpVP-2-type plasmid Kp52.145 II and could be readily conjugated to Escherichia coli strain EC600 and K. pneumoniae strains of various types which are clinically existing, mediating hypervirulence. Furthermore, this kind of conjugative KpVP-2-type virulence plasmid has been disseminated in clinical settings in Hong Kong and other regions of the world. The generation of conjugative virulence plasmid may promote its transmission and explain the evolution of this type of virulence plasmid.
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Affiliation(s)
- Xuemei Yang
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xiaoxuan Liu
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yating Xu
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Chen Yang
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Edward Wai-Chi Chan
- State Key Lab of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Hoi-ping Shum
- Department of Intensive Care, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong SAR, China
| | - Sheng Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- *Correspondence: Sheng Chen
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8
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Kochan TJ, Nozick SH, Medernach RL, Cheung BH, Gatesy SWM, Lebrun-Corbin M, Mitra SD, Khalatyan N, Krapp F, Qi C, Ozer EA, Hauser AR. Genomic surveillance for multidrug-resistant or hypervirulent Klebsiella pneumoniae among United States bloodstream isolates. BMC Infect Dis 2022; 22:603. [PMID: 35799130 PMCID: PMC9263067 DOI: 10.1186/s12879-022-07558-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 06/21/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Klebsiella pneumoniae strains have been divided into two major categories: classical K. pneumoniae, which are frequently multidrug-resistant and cause hospital-acquired infections in patients with impaired defenses, and hypervirulent K. pneumoniae, which cause severe community-acquired and disseminated infections in normal hosts. Both types of infections may lead to bacteremia and are associated with significant morbidity and mortality. The relative burden of these two types of K. pneumoniae among bloodstream isolates within the United States is not well understood. METHODS We evaluated consecutive K. pneumoniae isolates cultured from the blood of hospitalized patients at Northwestern Memorial Hospital (NMH) in Chicago, Illinois between April 2015 and April 2017. Bloodstream isolates underwent whole genome sequencing, and sequence types (STs), capsule loci (KLs), virulence genes, and antimicrobial resistance genes were identified in the genomes using the bioinformatic tools Kleborate and Kaptive. Patient demographic, comorbidity, and infection information, as well as the phenotypic antimicrobial resistance of the isolates were extracted from the electronic health record. Candidate hypervirulent isolates were tested in a murine model of pneumonia, and their plasmids were characterized using long-read sequencing. We also extracted STs, KLs, and virulence and antimicrobial resistance genes from the genomes of bloodstream isolates submitted from 33 United States institutions between 2007 and 2021 to the National Center for Biotechnology Information (NCBI) database. RESULTS Consecutive K. pneumoniae bloodstream isolates (n = 104, one per patient) from NMH consisted of 75 distinct STs and 51 unique capsule loci. The majority of these isolates (n = 58, 55.8%) were susceptible to all tested antibiotics except ampicillin, but 17 (16.3%) were multidrug-resistant. A total of 32 (30.8%) of these isolates were STs of known high-risk clones, including ST258 and ST45. In particular, 18 (17.3%) were resistant to ceftriaxone (of which 17 harbored extended-spectrum beta-lactamase genes) and 9 (8.7%) were resistant to meropenem (all of which harbored a carbapenemase genes). Four (3.8%) of the 104 isolates were hypervirulent K. pneumoniae, as evidenced by hypermucoviscous phenotypes, high levels of virulence in a murine model of pneumonia, and the presence of large plasmids similar to characterized hypervirulence plasmids. These isolates were cultured from patients who had not recently traveled to Asia. Two of these hypervirulent isolates belonged to the well characterized ST23 lineage and one to the re-emerging ST66 lineage. Of particular concern, two of these isolates contained plasmids with tra conjugation loci suggesting the potential for transmission. We also analyzed 963 publicly available genomes of K. pneumoniae bloodstream isolates from locations within the United States. Of these, 465 (48.3%) and 760 (78.9%) contained extended-spectrum beta-lactamase genes or carbapenemase genes, respectively, suggesting a bias towards submission of antibiotic-resistant isolates. The known multidrug-resistant high-risk clones ST258 and ST307 were the predominant sequence types. A total of 32 (3.3%) of these isolates contained aerobactin biosynthesis genes and 26 (2.7%) contained at least two genetic features of hvKP strains, suggesting elevated levels of virulence. We identified 6 (0.6%) isolates that were STs associated with hvKP: ST23 (n = 4), ST380 (n = 1), and ST65 (n = 1). CONCLUSIONS Examination of consecutive isolates from a single center demonstrated that multidrug-resistant high-risk clones are indeed common, but a small number of hypervirulent K. pneumoniae isolates were also observed in patients with no recent travel history to Asia, suggesting that these isolates are undergoing community spread in the United States. A larger collection of publicly available bloodstream isolate genomes also suggested that hypervirulent K. pneumoniae strains are present but rare in the USA; however, this collection appears to be heavily biased towards highly antibiotic-resistant isolates (and correspondingly away from hypervirulent isolates).
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Affiliation(s)
- Travis J Kochan
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
| | - Sophia H Nozick
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Rachel L Medernach
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Division of Infectious Diseases, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Bettina H Cheung
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Samuel W M Gatesy
- Division of Infectious Diseases, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Marine Lebrun-Corbin
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Sumitra D Mitra
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Natalia Khalatyan
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Fiorella Krapp
- Division of Infectious Diseases, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Chao Qi
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Egon A Ozer
- Division of Infectious Diseases, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Center for Pathogen Genomics and Microbial Evolution, Havey Institute for Global Health, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Alan R Hauser
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.,Division of Infectious Diseases, Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
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9
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Neumann B, Lippmann N, Wendt S, Karlas T, Lübbert C, Werner G, Pfeifer Y, Schuster CF. Recurrent bacteremia with a hypermucoviscous Escherichia coli isolated from a patient with perihilar cholangiocarcinoma: insights from a comprehensive genome-based analysis. Ann Clin Microbiol Antimicrob 2022; 21:28. [PMID: 35751078 PMCID: PMC9233328 DOI: 10.1186/s12941-022-00521-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/13/2022] [Indexed: 02/07/2023] Open
Abstract
Background Escherichia coli (E. coli) is a common human pathogen, responsible for a broad spectrum of infections. Sites of infection can vary, but the hepato-biliary system is of particular concern due to the infection-associated formation of gallstones and the spread of pathogens from the bile ducts into the bloodstream. Case presentation The presented case is striking, as the detected isolate showed a positive string test. This hypermucoviscous phenotype is atypical for E. coli and a particular feature of hypervirulent Klebsiella pneumoniae (K. pneumoniae) variants. Objectives To provide new insights into the genomic background of an E. coli strain with an unusual hypermucoviscous phenotype using hybrid short- and long-read sequencing approaches. Results Complete hybrid assemblies of the E. coli genome and plasmids were done and used for genome based typing. Isolate 537–20 was assigned to the multilocus sequence type ST88 and serotype O8:H4. The strain showed a close relationship to avian pathogenic strains. Analysis of the chromosome and plasmids revealed the presence of several virulence factors, such as the Conserved Virulence Plasmidic (CVP) region on plasmid 537-20_1, including several iron acquisition genes (sitABCD, iroABCDEN, iucABCD, hbd) and the iutA gene encoding the receptor of the siderophore aerobactin. The hypermucoviscous phenotype could be caused by encapsulation of putative K. pneumoniae origin. Conclusions Hybrid sequencing enabled detailed genomic characterization of the hypermucoviscous E. coli strain, revealing virulence factors that have their putative origin in K. pneumoniae. Supplementary Information The online version contains supplementary material available at 10.1186/s12941-022-00521-7.
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Affiliation(s)
- Bernd Neumann
- Division Nosocomial Pathogens and Antibiotic Resistance, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, 38855, Wernigerode, Germany. .,Institute for Hospital Hygiene, Medical Microbiology and Clinical Infectiology, Paracelsus Medical University, Nuremberg General Hospital, 90419, Nuremberg, Germany.
| | - Norman Lippmann
- Interdisciplinary Centre for Infectious Diseases, Leipzig University Hospital, 04103, Leipzig, Germany
| | - Sebastian Wendt
- Interdisciplinary Centre for Infectious Diseases, Leipzig University Hospital, 04103, Leipzig, Germany.,Division of Infectious Diseases and Tropical Medicine, Department of Medicine II, Leipzig University Hospital, 04103, Leipzig, Germany
| | - Thomas Karlas
- Division of Gastroenterology, Department of Medicine II, Leipzig University Medical Center, 04103, Leipzig, Germany
| | - Christoph Lübbert
- Interdisciplinary Centre for Infectious Diseases, Leipzig University Hospital, 04103, Leipzig, Germany.,Division of Infectious Diseases and Tropical Medicine, Department of Medicine II, Leipzig University Hospital, 04103, Leipzig, Germany
| | - Guido Werner
- Division Nosocomial Pathogens and Antibiotic Resistance, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, 38855, Wernigerode, Germany
| | - Yvonne Pfeifer
- Division Nosocomial Pathogens and Antibiotic Resistance, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, 38855, Wernigerode, Germany
| | - Christopher F Schuster
- Division Nosocomial Pathogens and Antibiotic Resistance, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, 38855, Wernigerode, Germany. .,Current Address: Center for Pandemic Vaccines and Therapeutics (ZEPAI), Paul-Ehrlich-Institute, 63225, Langen, Germany.
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10
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Wareth G, Linde J, Hammer P, Pletz MW, Neubauer H, Sprague LD. WGS-Based Phenotyping and Molecular Characterization of the Resistome, Virulome and Plasmid Replicons in Klebsiella pneumoniae Isolates from Powdered Milk Produced in Germany. Microorganisms 2022; 10:microorganisms10030564. [PMID: 35336140 PMCID: PMC8956024 DOI: 10.3390/microorganisms10030564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/03/2022] [Accepted: 03/03/2022] [Indexed: 02/04/2023] Open
Abstract
The emergence of Klebsiella pneumoniae (K. pneumoniae) in German healthcare is worrying. It is not well-investigated in the veterinary world and food chains. In the current study, antibiotic susceptibility profiles of 24 K. pneumoniae strains isolated from powdered milk samples produced in Germany were investigated by a microdilution test. Next-generation sequencing (NGS) was applied to identify genomic determinants for antimicrobial resistance (AMR), virulence-associated genes and plasmids replicons. All isolates were susceptible to the majority (14/18) of tested antibiotics. Resistance to colistin, fosfomycin, chloramphenicol and piperacillin was found. The ambler class A ß-lactamase, blaSHV variants were identified in all isolates, of which blaSHV-187 was most prevalent and found in 50% of isolates. Single-nucleotide-variants of oqxA and oqxB conferring resistance to phenicol/quinolone were found in all isolates, and the oqxB17 was the most prevalent found in 46% of isolates. 67% of isolates harbored fosA genes; however, only one was fosfomycin-resistant. Two isolates harbored genes conferring resistance to colistin, despite being susceptible. The majority of identified virulome genes were iron uptake siderophores. Two enterobactins (entB, fepC), six adherence-related genes belonging to E. coli common pilus (ECP) and one secretion system (ompA gene) were found in all isolates. In contrast, yersiniabactin was found in two isolates. One ST23 strain was susceptible to all tested antibiotics, and harbored determinants discriminatory for hypervirulent strains, e.g., aerobactin, salmochelin, yersiniabactin, enterobactin and regulator of mucoid phenotype A genes that are highly associated with hypervirulent K. pneumoniae. The IncF plasmid family was found in all strains, while almost half of the isolates harbored Col440I-type plasmids and nine isolates harbored various Inc-type plasmids. The presence of K. pneumoniae carrying different resistomes and major virulent specific virulomes in powdered milk samples is alarming. This could threaten public health, particularly of neonates and infants consuming dried milk.
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Affiliation(s)
- Gamal Wareth
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses (IBIZ), Naumburger Str. 96a, 07743 Jena, Germany; (J.L.); (H.N.); (L.D.S.)
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena University, 07743 Jena, Germany;
- Department of Bacteriology, Immunology and Mycology, Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt
- Correspondence:
| | - Jörg Linde
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses (IBIZ), Naumburger Str. 96a, 07743 Jena, Germany; (J.L.); (H.N.); (L.D.S.)
| | - Philipp Hammer
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany;
| | - Mathias W. Pletz
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena University, 07743 Jena, Germany;
- Research Campus Infectognostics, Philosophenweg 7, 07743 Jena, Germany
| | - Heinrich Neubauer
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses (IBIZ), Naumburger Str. 96a, 07743 Jena, Germany; (J.L.); (H.N.); (L.D.S.)
| | - Lisa D. Sprague
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses (IBIZ), Naumburger Str. 96a, 07743 Jena, Germany; (J.L.); (H.N.); (L.D.S.)
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11
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Huang W, Zhang J, Zeng L, Yang C, Yin L, Wang J, Li J, Li X, Hu K, Zhang X, Liu B. Carbapenemase Production and Epidemiological Characteristics of Carbapenem-Resistant Klebsiella pneumoniae in Western Chongqing, China. Front Cell Infect Microbiol 2022; 11:775740. [PMID: 35071036 PMCID: PMC8769044 DOI: 10.3389/fcimb.2021.775740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/13/2021] [Indexed: 11/29/2022] Open
Abstract
Background This study aimed to determine the molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates in a hospital in western Chongqing, southwestern China. Methods A total of 127 unique CRKP isolates were collected from the Yongchuan Hospital of Chongqing Medical University, identified using a VITEK-2 compact system, and subjected to microbroth dilution to determine the minimal inhibitory concentration. Enterobacteriaceae intergenic repeat consensus polymerase chain reaction and multilocus sequence typing were used to analyze the homology among the isolates. Genetic information, including resistance and virulence genes, was assessed using polymerase chain reaction. The genomic features of the CRKP carrying gene blaKPC-2 were detected using whole-genome sequencing. Results ST11 was the dominant sequence type in the homology comparison. The resistance rate to ceftazidime-avibactam in children was much higher than that in adults as was the detection rate of the resistance gene blaNDM (p < 0.0001). Virulence genes such as mrkD (97.6%), uge (96.9%), kpn (96.9%), and fim-H (84.3%) had high detection rates. IncF (57.5%) was the major replicon plasmid detected, and sequencing showed that the CRKP063 genome contained two plasmids. The plasmid carrying blaKPC-2, which mediates carbapenem resistance, was located on the 359,625 base pair plasmid IncFII, together with virulence factors, plasmid replication protein (rep B), stabilizing protein (par A), and type IV secretion system (T4SS) proteins that mediate plasmid conjugation transfer. Conclusion Our study aids in understanding the prevalence of CRKP in this hospital and the significant differences between children and adults, thus providing new ideas for clinical empirical use of antibiotics.
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Affiliation(s)
- Wan Huang
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Jisheng Zhang
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Lingyi Zeng
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China.,Department of Microbiology, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, China
| | - Chengru Yang
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China.,Department of Microbiology, The First Affiliated Hospital of Jiamusi University, Jiamusi, China
| | - Lining Yin
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China.,Department of Microbiology, The First Affiliated Hospital of Jiamusi University, Jiamusi, China
| | - Jianmin Wang
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Jie Li
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Xinhui Li
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China
| | - Kewang Hu
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China.,Department of Microbiology, Affiliated Hangzhou Xixi Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoli Zhang
- Department of Microbiology, Yongchuan Hospital of Chongqing Medical University, Chongqing, China.,Department of Microbiology, The First Affiliated Hospital of Jiamusi University, Jiamusi, China
| | - Beizhong Liu
- Central Laboratory of Yongchuan Hospital, Chongqing Medical University, Chongqing, China
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12
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Kamau E, Allyn PR, Beaird OE, Ward KW, Kwan N, Garner OB, Yang S. Endogenous Endophthalmitis Caused by ST66-K2 Hypervirulent Klebsiella pneumoniae, United States. Emerg Infect Dis 2021; 27:2215-2218. [PMID: 34287130 PMCID: PMC8314818 DOI: 10.3201/eid2708.210234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We describe a case of endogenous endophthalmitis caused by sequence type 66-K2 hypervirulent Klebsiella pneumoniae in a diabetic patient with no travel history outside the United States. Genomic analysis showed the pathogen has remained highly conserved, retaining >98% genetic similarity to the original strain described in Indonesia in 1935.
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13
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Isolation and Characterization of a Novel Lytic Bacteriophage against the K2 Capsule-Expressing Hypervirulent Klebsiella pneumoniae Strain 52145, and Identification of Its Functional Depolymerase. Microorganisms 2021; 9:microorganisms9030650. [PMID: 33801047 PMCID: PMC8003838 DOI: 10.3390/microorganisms9030650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 12/30/2022] Open
Abstract
Klebsiella pneumoniae is among the leading bacteria that cause nosocomial infections. The capsule of this Gram-negative bacterium is a dominant virulence factor, with a prominent role in defense and biofilm formation. Bacteriophages, which are specific for one bacterial strain and its capsule type, can evoke the lysis of bacterial cells, aided by polysaccharide depolymerase enzymes. In this study, we isolated and characterized a bacteriophage against the nosocomial K. pneumoniae 52145 strain with K2 capsular serotype. The phage showed a narrow host range and stable lytic activity, even when exposed to different temperatures or detergents. Preventive effect of the phage in a nasal colonization model was investigated in vivo. Phlyogenetic analysis showed that the newly isolated Klebsiella phage B1 belongs to the Webervirus genus in Drexlerviridae family. We identified the location of the capsule depolymerase gene of the new phage, which was amplified, cloned, expressed, and purified. The efficacy of the recombinant B1dep depolymerase was tested by spotting on K. pneumoniae strains and it was confirmed that the extract lowers the thickness of the bacterium lawn as it degrades the protective capsule on bacterial cells. As K. pneumoniae strains possessing the K2 serotype have epidemiological importance, the B1 phage and its depolymerase are promising candidates for use as possible antimicrobial agents.
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14
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The PTS Components in Klebsiella pneumoniae Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance. Microorganisms 2021; 9:microorganisms9020335. [PMID: 33567595 PMCID: PMC7914778 DOI: 10.3390/microorganisms9020335] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/04/2022] Open
Abstract
Capsular polysaccharide (CPS) is a crucial virulence factor for Klebsiella pneumoniae infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of crr, encoding enzyme IIA of PTS, in K. pneumoniae enhanced the transcriptional activities of galF, wzi and gnd, which are in the cps gene cluster, leading to high CPS production. A crr mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The crr mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular crr mutant was higher than that of the wild-type. Deficiency of crr enhanced the transcriptional activities of etcABC which encodes another putative enzyme II complex of a PTS. Deletion of etcABC in the crr mutant reduced CPS production and the transcriptional activities of galF compared to those of the crr mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in K. pneumoniae. In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.
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