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Ceres K, Zehr JD, Murrell C, Millet JK, Sun Q, McQueary HC, Horton A, Cazer C, Sams K, Reboul G, Andreopoulos WB, Mitchell PK, Anderson R, Franklin-Guild R, Cronk BD, Stanhope BJ, Burbick CR, Wolking R, Peak L, Zhang Y, McDowall R, Krishnamurthy A, Slavic D, Sekhon PK, Tyson GH, Ceric O, Stanhope MJ, Goodman LB. Evolutionary genomic analyses of canine E. coli infections identify a relic capsular locus associated with resistance to multiple classes of antimicrobials. Appl Environ Microbiol 2024:e0035424. [PMID: 39012166 DOI: 10.1128/aem.00354-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/08/2024] [Indexed: 07/17/2024] Open
Abstract
Infections caused by antimicrobial-resistant Escherichia coli are the leading cause of death attributed to antimicrobial resistance (AMR) worldwide, and the known AMR mechanisms involve a range of functional proteins. Here, we employed a pan-genome wide association study (GWAS) approach on over 1,000 E. coli isolates from sick dogs collected across the US and Canada and identified a strong statistical association (empirical P < 0.01) of AMR, involving a range of antibiotics to a group 1 capsular (CPS) gene cluster. This cluster included genes under relaxed selection pressure, had several loci missing, and had pseudogenes for other key loci. Furthermore, this cluster is widespread in E. coli and Klebsiella clinical isolates across multiple host species. Earlier studies demonstrated that the octameric CPS polysaccharide export protein Wza can transmit macrolide antibiotics into the E. coli periplasm. We suggest that the CPS in question, and its highly divergent Wza, functions as an antibiotic trap, preventing antimicrobial penetration. We also highlight the high diversity of lineages circulating in dogs across all regions studied, the overlap with human lineages, and regional prevalence of resistance to multiple antimicrobial classes. IMPORTANCE Much of the human genomic epidemiology data available for E. coli mechanism discovery studies has been heavily biased toward shiga-toxin producing strains from humans and livestock. E. coli occupies many niches and produces a wide variety of other significant pathotypes, including some implicated in chronic disease. We hypothesized that since dogs tend to share similar strains with their owners and are treated with similar antibiotics, their pathogenic isolates will harbor unexplored AMR mechanisms of importance to humans as well as animals. By comparing over 1,000 genomes with in vitro antimicrobial susceptibility data from sick dogs across the US and Canada, we identified a strong multidrug resistance association with an operon that appears to have once conferred a type 1 capsule production system.
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Affiliation(s)
| | | | | | - Jean K Millet
- Université Paris-Saclay, INRAE, UVSQ, Virologie et Immunologie Moléculaires, Jouy-en-Josas, Paris, France
| | - Qi Sun
- Cornell University, Ithaca, New York, USA
| | | | | | | | - Kelly Sams
- Cornell University, Ithaca, New York, USA
| | | | | | | | | | | | | | | | - Claire R Burbick
- Washington Animal Disease Diagnostic Laboratory, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Rebecca Wolking
- Washington Animal Disease Diagnostic Laboratory, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Laura Peak
- Louisiana Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Yan Zhang
- Ohio Department of Agriculture Animal Disease Diagnostic Laboratory, Reynoldsburg, Ohio, USA
| | - Rebeccah McDowall
- University of Guelph, Animal Health Laboratory, Guelph, Ontario, Canada
| | | | - Durda Slavic
- University of Guelph, Animal Health Laboratory, Guelph, Ontario, Canada
| | | | - Gregory H Tyson
- US Food and Drug Administration, Veterinary Laboratory Investigation and Response Network, Laurel, Maryland, USA
| | - Olgica Ceric
- US Food and Drug Administration, Veterinary Laboratory Investigation and Response Network, Laurel, Maryland, USA
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AL-Busaidi B, AL-Muzahmi M, AL-Shabibi Z, Rizvi M, AL-Rashdi A, AL-Jardani A, Farzand R, AL-Jabri Z. Hypervirulent Capsular Serotypes K1 and K2 Klebsiella pneumoniae Strains Demonstrate Resistance to Serum Bactericidal Activity and Galleria mellonella Lethality. Int J Mol Sci 2024; 25:1944. [PMID: 38339222 PMCID: PMC10855873 DOI: 10.3390/ijms25031944] [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: 01/05/2024] [Revised: 01/28/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Hypervirulent Klebsiella pneumoniae (hvKp) is a variant that has been increasingly linked to severe, life-threatening infections including pyogenic liver abscess and bloodstream infections. HvKps belonging to the capsular serotypes K1 and K2 have been reported worldwide, however, very scarce studies are available on their genomics and virulence. In the current study, we report four hypermucoviscous extended-spectrum β-lactamase-producing hvKp clinical strains of capsular serotype K1 and K2 isolated from pus and urine of critically ill patients in tertiary care hospitals in Oman. These strains belong to diverse sequence types (STs), namely ST-23(K1), ST-231(K2), ST-881(K2), and ST-14(K2). To study their virulence, a Galleria mellonella model and resistance to human serum killing were used. The G. mellonella model revealed that the K1/ST-23 isolate was the most virulent, as 50% of the larvae died in the first day, followed by isolate K2/ST-231 and K2/ST-14, for which 75% and 50% of the larvae died in the second day, respectively. Resistance to human serum killing showed there was complete inhibition of bacterial growth of all four isolates by the end of the first hour and up to the third hour. Whole genome sequencing (WGS) revealed that hvKp strains display a unique genetic arrangement of k-loci. Whole-genome single-nucleotide polymorphism-based phylogenetic analysis revealed that these hvKp isolates were phylogenetically distinct, belonging to diverse clades, and belonged to different STs in comparison to global isolates. For ST-23(K1), ST-231(K2), ST-881(K2), and ST-14(K2), there was a gradual decrease in the number of colonies up to the second to third hour, which indicates neutralization of bacterial cells by the serum components. However, this was followed by a sudden increase of bacterial growth, indicating possible resistance of bacteria against human serum bactericidal activity. This is the first report from Oman detailing the WGS of hvKp clinical isolates and assessing their resistance and virulence genomics, which reinforce our understanding of their epidemiology and dissemination in clinical settings.
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Affiliation(s)
- Basaier AL-Busaidi
- Microbiology and Immunology Diagnostic Laboratory, Department of Microbiology and Immunology, Sultan Qaboos University Hospital, Muscat 123, Oman;
| | | | - Zahra AL-Shabibi
- Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University Hospital, Muscat 123, Oman;
| | - Meher Rizvi
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Azza AL-Rashdi
- Central Public Health Laboratory, Department of Medical Microbiology, Ministry of Health, Muscat 100, Oman; (A.A.-R.); (A.A.-J.)
| | - Amina AL-Jardani
- Central Public Health Laboratory, Department of Medical Microbiology, Ministry of Health, Muscat 100, Oman; (A.A.-R.); (A.A.-J.)
| | - Robeena Farzand
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK;
| | - Zaaima AL-Jabri
- Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University Hospital, Muscat 123, Oman;
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Ovchinnikova OG, Treat LP, Teelucksingh T, Clarke BR, Miner TA, Whitfield C, Walker KA, Miller VL. Hypermucoviscosity Regulator RmpD Interacts with Wzc and Controls Capsular Polysaccharide Chain Length. mBio 2023; 14:e0080023. [PMID: 37140436 PMCID: PMC10294653 DOI: 10.1128/mbio.00800-23] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/05/2023] Open
Abstract
Klebsiella pneumoniae is a leading cause of nosocomial infections, including pneumonia, bacteremia, and urinary tract infections. Treatment options are increasingly restricted by the high prevalence of resistance to frontline antibiotics, including carbapenems, and the recently identified plasmid-conferred colistin resistance. The classical pathotype (cKp) is responsible for most of the nosocomial infections observed globally, and these isolates are often multidrug resistant. The hypervirulent pathotype (hvKp) is a primary pathogen capable of causing community-acquired infections in immunocompetent hosts. The hypermucoviscosity (HMV) phenotype is strongly associated with the increased virulence of hvKp isolates. Recent studies demonstrated that HMV requires capsule (CPS) synthesis and the small protein RmpD but is not dependent on the increased amount of capsule associated with hvKp. Here, we identified the structure of the capsular and extracellular polysaccharide isolated from hvKp strain KPPR1S (serotype K2) with and without RmpD. We found that the polymer repeat unit structure is the same in both strains and that it is identical to the K2 capsule. However, the chain length of CPS produced by strains expressing rmpD demonstrates more uniform length. This property was reconstituted in CPS from Escherichia coli isolates that possess the same CPS biosynthesis pathway as K. pneumoniae but naturally lack rmpD. Furthermore, we demonstrate that RmpD binds Wzc, a conserved capsule biosynthesis protein required for CPS polymerization and export. Based on these observations, we present a model for how the interaction of RmpD with Wzc could impact CPS chain length and HMV. IMPORTANCE Infections caused by Klebsiella pneumoniae continue to be a global public health threat; the treatment of these infections is complicated by the high frequency of multidrug resistance. K. pneumoniae produces a polysaccharide capsule required for virulence. Hypervirulent isolates also have a hypermucoviscous (HMV) phenotype that increases virulence, and we recently demonstrated that a horizontally acquired gene, rmpD, is required for HMV and hypervirulence but that the identity of the polymeric product(s) in HMV isolates is uncertain. Here, we demonstrate that RmpD regulates capsule chain length and interacts with Wzc, a part of the capsule polymerization and export machinery shared by many pathogens. We further show that RmpD confers HMV and regulates capsule chain length in a heterologous host (E. coli). As Wzc is a conserved protein found in many pathogens, it is possible that RmpD-mediated HMV and increased virulence may not be restricted to K. pneumoniae.
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Affiliation(s)
- Olga G. Ovchinnikova
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Logan P. Treat
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Tanisha Teelucksingh
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Bradley R. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Taryn A. Miner
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Kimberly A. Walker
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Virginia L. Miller
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
- Department of Genetics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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Huang M, He P, He P, Wu Y, Munir S, He Y. Novel Virulence Factors Deciphering Klebsiella pneumoniae KpC4 Infect Maize as a Crossing-Kingdom Pathogen: An Emerging Environmental Threat. Int J Mol Sci 2022; 23:ijms232416005. [PMID: 36555647 PMCID: PMC9785288 DOI: 10.3390/ijms232416005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Klebsiella pneumoniae is not only a human and animal opportunistic pathogen, but a food-borne pathogen. Cross-kingdom infection has been focused on since K. pneumoniae was identified as the pathogen of maize, banana, and pomegranate. Although the pathogenicity of K. pneumoniae strains (from ditch water, maize, and human) on plant and mice has been confirmed, there are no reports to explain the molecular mechanisms of the pathogen. This study uncovered the K. pneumoniae KpC4 isolated from maize top rot for the determination of various virulence genes and resistance genes. At least thirteen plant disease-causing genes are found to be involved in the disruption of plant defense. Among them, rcsB is responsible for causing disease in both plants and animals. The novel sequence types provide solid evidence that the pathogen invades plant and has robust ecological adaptability. It is imperative to perform further studies on the verification of these KpC4 genes’ functions to understand the molecular mechanisms involved in plant−pathogen interactions.
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Affiliation(s)
- Min Huang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
- College of Agronomy and Life Sciences and Engineering Research Center for Urban Modern Agriculture of Higher Education in Yunnan Province, Kunming University, Kunming 650214, China
| | - Pengfei He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
| | - Pengbo He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
| | - Yixin Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
| | - Shahzad Munir
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
- Correspondence: (S.M.); (Y.H.)
| | - Yueqiu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
- Correspondence: (S.M.); (Y.H.)
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Topolski C, Divo E, Li X, Hicks J, Chavez A, Castillo H. Phenotypic and transcriptional changes in Escherichia coli K12 in response to simulated microgravity on the EagleStat, a new 2D microgravity analog for bacterial studies. LIFE SCIENCES IN SPACE RESEARCH 2022; 34:1-8. [PMID: 35940684 DOI: 10.1016/j.lssr.2022.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 06/15/2023]
Abstract
Understanding the impacts of microgravity on bacteria is vital for successful long duration space missions. In this environment, bacteria have been shown to become more virulent, more resistant to antibiotics and to regulate biofilm formation. Since the study of these phenomena under true microgravity is cost- and time challenging, the use of ground-based analogs might allow researchers to test hypotheses before planning and executing experiments in the space environment. We designed and developed a 2D clinostat with capabilities robust enough for bacterial studies to allow for multiple simultaneous replicates of treatment and control conditions, thus permitting the generation of growth curves, in a single run. We used computational fluid dynamics (CFD), biofilm growth measurement and differential gene expression analysis on Escherichia coli cultures grown to late exponential phase (24 h) to validate the system's ability to simulate microgravity conditions. The CFD model with a rotational speed of 8 rpm projected cells growing homogeneously distributed along the tube, while the static condition showed the accumulation of the cells at the bottom of the container. These results were empirically validated with cultures on nutrient broth. Additionally, crystal violet assays showed that higher biofilm biomass grew on the internal walls of the gravity control tubes, compared to the simulated microgravity treatment. In contrast, when cells from both treatments were grown under standard conditions, those exposed to simulated microgravity formed significantly more biofilms than their gravity counterparts. Consistent with this result, transcriptome analysis showed the upregulation of several gene families related to biofilm formation and development such as cells adhesion, aggregation and regulation of cell motility, which provides a potential transcriptional explanation for the differential phenotype observed. Our results show that when operated under parameters for simulated microgravity, our 2D clinostat creates conditions that maintain a proportion of the cells in a constant free-falling state, consistent with the effect of microgravity. Also, the high-throughput nature of our instrument facilitates, significantly, bacterial experiments that require multiple sampling timepoints and small working volumes, making this new instrument extremely efficient.
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Affiliation(s)
- Collin Topolski
- Mechanical Engineering Department, Embry-Riddle Aeronautical University, Daytona Beach, FL, USA
| | - Eduardo Divo
- Mechanical Engineering Department, Embry-Riddle Aeronautical University, Daytona Beach, FL, USA
| | - Xiaoping Li
- Virginia Tech Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Blacksburg, VA, USA
| | - Janelle Hicks
- Human Factors and Behavioral Neurobiology Department, Embry-Riddle Aeronautical University, 1 Aerospace Blvd, COAS 401.03, Deland, Florida, 32724 USA
| | - Alba Chavez
- Human Factors and Behavioral Neurobiology Department, Embry-Riddle Aeronautical University, 1 Aerospace Blvd, COAS 401.03, Deland, Florida, 32724 USA
| | - Hugo Castillo
- Human Factors and Behavioral Neurobiology Department, Embry-Riddle Aeronautical University, 1 Aerospace Blvd, COAS 401.03, Deland, Florida, 32724 USA.
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6
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Sande C, Whitfield C. Capsules and Extracellular Polysaccharides in Escherichia coli and Salmonella. EcoSal Plus 2021; 9:eESP00332020. [PMID: 34910576 PMCID: PMC11163842 DOI: 10.1128/ecosalplus.esp-0033-2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 10/26/2021] [Indexed: 12/16/2022]
Abstract
Escherichia coli and Salmonella isolates produce a range of different polysaccharide structures that play important roles in their biology. E. coli isolates often possess capsular polysaccharides (K antigens), which form a surface structural layer. These possess a wide range of repeat-unit structures. In contrast, only one capsular polymer (Vi antigen) is found in Salmonella, and it is confined to typhoidal serovars. In both genera, capsules are vital virulence determinants and are associated with the avoidance of host immune defenses. Some isolates of these species also produce a largely secreted exopolysaccharide called colanic acid as part of their complex Rcs-regulated phenotypes, but the precise function of this polysaccharide in microbial cell biology is not fully understood. E. coli isolates produce two additional secreted polysaccharides, bacterial cellulose and poly-N-acetylglucosamine, which play important roles in biofilm formation. Cellulose is also produced by Salmonella isolates, but the genes for poly-N-acetylglucosamine synthesis appear to have been lost during its evolution toward enhanced virulence. Here, we discuss the structures, functions, relationships, and sophisticated assembly mechanisms for these important biopolymers.
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Affiliation(s)
- Caitlin Sande
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Kaszowska M, Majkowska-Skrobek G, Markwitz P, Lood C, Jachymek W, Maciejewska A, Lukasiewicz J, Drulis-Kawa Z. The Mutation in wbaP cps Gene Cluster Selected by Phage-Borne Depolymerase Abolishes Capsule Production and Diminishes the Virulence of Klebsiella pneumoniae. Int J Mol Sci 2021; 22:11562. [PMID: 34768992 PMCID: PMC8583740 DOI: 10.3390/ijms222111562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/21/2021] [Accepted: 10/21/2021] [Indexed: 12/20/2022] Open
Abstract
Klebsiella pneumoniae is considered one of the most critical multidrug-resistant pathogens and urgently requires new therapeutic strategies. Capsular polysaccharides (CPS), lipopolysaccharides (LPS), and exopolysaccharides (EPS) are the major virulence factors protecting K. pneumoniae against the immune response and thus may be targeted by phage-based therapeutics such as polysaccharides-degrading enzymes. Since the emergence of resistance to antibacterials is generally considered undesirable, in this study, the genetic and phenotypic characteristics of resistance to the phage-borne CPS-degrading depolymerase and its effect on K. pneumoniae virulence were investigated. The K63 serotype targeting depolymerase (KP36gp50) derived from Klebsiella siphovirus KP36 was used as the selective agent during the treatment of K. pneumoniae 486 biofilm. Genome-driven examination combined with the surface polysaccharide structural analysis of resistant mutant showed the point mutation and frameshift in the wbaP gene located within the cps gene cluster, resulting in the loss of the capsule. The sharp decline in the yield of CPS was accompanied by the production of a larger amount of smooth LPS. The modification of the surface polysaccharide layers did not affect bacterial fitness nor the insensitivity to serum complement; however, it made bacteria more prone to phagocytosis combined with the higher adherence and internalization to human lung epithelial cells. In that context, it was showed that the emerging resistance to the antivirulence agent (phage-borne capsule depolymerase) results in beneficial consequences, i.e., the sensitization to the innate immune response.
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Affiliation(s)
- Marta Kaszowska
- Laboratory of Microbial Immunochemistry and Vaccines, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (M.K.); (W.J.); (A.M.)
| | - Grazyna Majkowska-Skrobek
- Department of Pathogen Biology and Immunology, University of Wroclaw, 51-148 Wroclaw, Poland; (G.M.-S.); (P.M.)
| | - Pawel Markwitz
- Department of Pathogen Biology and Immunology, University of Wroclaw, 51-148 Wroclaw, Poland; (G.M.-S.); (P.M.)
| | - Cédric Lood
- Department of Microbial and Molecular Systems, KU Leuven, 3001 Leuven, Belgium;
- Department of Biosystems, KU Leuven, 3001 Leuven, Belgium
| | - Wojciech Jachymek
- Laboratory of Microbial Immunochemistry and Vaccines, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (M.K.); (W.J.); (A.M.)
| | - Anna Maciejewska
- Laboratory of Microbial Immunochemistry and Vaccines, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (M.K.); (W.J.); (A.M.)
| | - Jolanta Lukasiewicz
- Laboratory of Microbial Immunochemistry and Vaccines, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (M.K.); (W.J.); (A.M.)
| | - Zuzanna Drulis-Kawa
- Department of Pathogen Biology and Immunology, University of Wroclaw, 51-148 Wroclaw, Poland; (G.M.-S.); (P.M.)
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Prophylaxis and Treatment against Klebsiella pneumoniae: Current Insights on This Emerging Anti-Microbial Resistant Global Threat. Int J Mol Sci 2021; 22:ijms22084042. [PMID: 33919847 PMCID: PMC8070759 DOI: 10.3390/ijms22084042] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/06/2021] [Accepted: 04/12/2021] [Indexed: 02/07/2023] Open
Abstract
Klebsiella pneumoniae (Kp) is an opportunistic pathogen and the leading cause of healthcare-associated infections, mostly affecting subjects with compromised immune systems or suffering from concurrent bacterial infections. However, the dramatic increase in hypervirulent strains and the emergence of new multidrug-resistant clones resulted in Kp occurrence among previously healthy people and in increased morbidity and mortality, including neonatal sepsis and death across low- and middle-income countries. As a consequence, carbapenem-resistant and extended spectrum β-lactamase-producing Kp have been prioritized as a critical anti-microbial resistance threat by the World Health Organization and this has renewed the interest of the scientific community in developing a vaccine as well as treatments alternative to the now ineffective antibiotics. Capsule polysaccharide is the most important virulence factor of Kp and plays major roles in the pathogenesis but its high variability (more than 100 different types have been reported) makes the identification of a universal treatment or prevention strategy very challenging. However, less variable virulence factors such as the O-Antigen, outer membrane proteins as fimbriae and siderophores might also be key players in the fight against Kp infections. Here, we review elements of the current status of the epidemiology and the molecular pathogenesis of Kp and explore specific bacterial antigens as potential targets for both prophylactic and therapeutic solutions.
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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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Ssekatawa K, Byarugaba DK, Nakavuma JL, Kato CD, Ejobi F, Tweyongyere R, Eddie WM. Prevalence of pathogenic Klebsiella pneumoniae based on PCR capsular typing harbouring carbapenemases encoding genes in Uganda tertiary hospitals. Antimicrob Resist Infect Control 2021; 10:57. [PMID: 33736698 PMCID: PMC7977577 DOI: 10.1186/s13756-021-00923-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/02/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Klebsiella pneumoniae is an opportunistic pathogen that has been implicated as one of commonest cause of hospital and community acquired infections. The K. pneumoniae infections have considerably contributed to morbidity and mortality in patients with protracted ailments. The capacity of K. pneumoniae to cause diseases depends on the presence of an array virulence factors. Coexistence and expression of virulence factors and genetic determinants of antibiotic resistance complicates treatment outcomes. Thus, emergence of pathogenic MDR K. pneumoniae poses a great threat to the healthcare system. However, the carriage of antibiotic resistance among pathogenic K. pneumoniae is yet to be investigated in Uganda. We sought to investigate the carbapenem resistance profiles and pathogenic potential based on capsular serotypes of K. pneumoniae clinical isolates. METHODS This was a cross sectional study involving use of archived Klebsiella pneumoniae isolates collected between January and December, 2019 at four tertiary hospitals in Uganda. All isolates were subject to antimicrobial susceptibility assays to determine phenotypic antibiotic resistance, pentaplex PCR to detect carbapenemases encoding genes and heptaplex PCR to identify capsular serotypes K1, K2, K3, K5, K20, K54 and K57. RESULTS The study found an overall phenotypic carbapenem resistance of 23.3% (53/227) and significantly higher genotypic resistance prevalence of 43.1% (98/227). Over all, the most prevalent gene was blaOXA-48-like (36.4%), followed by blaIMP-type (19.4%), blaVIM-type (17.1%), blaKPC-type (14.0%) and blaNDM-type (13.2%). blaVIM-type and blaOXA-48-like conferred phenotypic resistance in all isolates and 38.3% of isolates that harbored them respectively. Capsular multiplex PCR revealed that 46.7% (106/227) isolates were pathogenic and the predominantly prevalent pathotype was K5 (18.5%) followed by K20 (15.1%), K3 (7.1%), K2 (3.1%) and K1 (2.2%). Of the 106 capsular serotypes, 37 expressed phenotypic resistance; thus, 37 of the 53 carbapenem resistant K. pneumoniae were pathogenic. CONCLUSION The high prevalence of virulent and antibiotic resistant K. pneumoniae among clinical isolates obtained from the four tertiary hospital as revealed by this study pose a great threat to healthcare. Our findings underline the epidemiological and public health risks and implications of this pathogen.
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Affiliation(s)
- Kenneth Ssekatawa
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
- Department of Biochemistry, Faculty of Biomedical Sciences, Kampala International University-Western Campus, P. O. Box 71, Bushenyi, Uganda
- Africa Center Excellence in Materials Product Development and Nanotechnology (MAPRONANO ACE), College of Engineering Design Art and Technology, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Denis K. Byarugaba
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Jesca L. Nakavuma
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Charles D. Kato
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Francis Ejobi
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Robert Tweyongyere
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Wampande M. Eddie
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
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Choi E, Jeon H, Oh C, Hwang J. Elucidation of a Novel Role of YebC in Surface Polysaccharides Regulation of Escherichia coli bipA-Deletion. Front Microbiol 2020; 11:597515. [PMID: 33240252 PMCID: PMC7682190 DOI: 10.3389/fmicb.2020.597515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/23/2020] [Indexed: 12/19/2022] Open
Abstract
The BipA (BPI-inducible protein A) protein is ubiquitously conserved in various bacterial species and belongs to the translational GTPase family. Interestingly, the function of Escherichia coli BipA is not essential for cell growth under normal growth conditions. However, cultivation of bipA-deleted cells at 20°C leads to cold-sensitive growth defect and several phenotypic changes in ribosome assembly, capsule production, and motility, suggesting its global regulatory roles. Previously, our genomic library screening revealed that the overexpressed ribosomal protein (r-protein) L20 partially suppressed cold-sensitive growth defect by resolving the ribosomal abnormality in bipA-deleted cells at low temperature. Here, we explored another genomic library clone containing yebC, which encodes a predicted transcriptional factor that is not directly associated with ribosome biogenesis. Interestingly, overexpression of yebC in bipA-deleted cells diminished capsule synthesis and partially restored lipopolysaccharide (LPS) core maturation at a low temperature without resolving defects in ribosome assembly or motility, indicating that YebC may be specifically involved in the regulation of exopolysaccharide and LPS core synthesis. In this study, we collectively investigated the impacts of bipA-deletion on E. coli capsule, LPS, biofilm formation, and motility and revealed novel roles of YebC in extracellular polysaccharide production and LPS core synthesis at low temperature using this mutant strain. Furthermore, our findings suggest that ribosomal defects as well as increased capsule synthesis, and changes in LPS composition may contribute independently to the cold-sensitivity of bipA-deleted cells, implying multiple regulatory roles of BipA.
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Affiliation(s)
- Eunsil Choi
- Microbiological Resource Research Institute, Pusan National University, Busan, South Korea.,Department of Microbiology, Pusan National University, Busan, South Korea
| | - Hyerin Jeon
- Microbiological Resource Research Institute, Pusan National University, Busan, South Korea
| | - Changmin Oh
- Microbiological Resource Research Institute, Pusan National University, Busan, South Korea
| | - Jihwan Hwang
- Microbiological Resource Research Institute, Pusan National University, Busan, South Korea.,Department of Microbiology, Pusan National University, Busan, South Korea
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12
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Patro LPP, Sudhakar KU, Rathinavelan T. K-PAM: a unified platform to distinguish Klebsiella species K- and O-antigen types, model antigen structures and identify hypervirulent strains. Sci Rep 2020; 10:16732. [PMID: 33028855 PMCID: PMC7541508 DOI: 10.1038/s41598-020-73360-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 08/11/2020] [Indexed: 12/14/2022] Open
Abstract
A computational method has been developed to distinguish the Klebsiella species serotypes to aid in outbreak surveillance. A reliability score (estimated based on the accuracy of a specific K-type prediction against the dataset of 141 distinct K-types) average (ARS) that reflects the specificity between the Klebsiella species capsular polysaccharide biosynthesis and surface expression proteins, and their K-types has been established. ARS indicates the following order of potency in accurate serotyping: Wzx (ARS = 98.5%),Wzy (ARS = 97.5%),WbaP (ARS = 97.2%),Wzc (ARS = 96.4%),Wzb (ARS = 94.3%),WcaJ (ARS = 93.8%),Wza (ARS = 79.9%) and Wzi (ARS = 37.1%). Thus, Wzx, Wzy and WbaP can give more reliable K-typing compared with other proteins. A fragment-based approach has further increased the Wzi ARS from 37.1% to 80.8%. The efficacy of these 8 proteins in accurate K-typing has been confirmed by a rigorous testing and the method has been automated as K-PAM (www.iith.ac.in/K-PAM/). Testing also indicates that the use of multiple genes/proteins helps in reducing the K-type multiplicity, distinguishing the K-types that have identical K-locus (like KN3 and K35) and identifying the ancestral serotypes of Klebsiella spp. K-PAM has the facilities to O-type using Wzm (ARS = 85.7%) and Wzt (ARS = 85.7%) and identifies the hypervirulent Klebsiella species by the use of rmpA, rmpA2, iucA, iroB and peg-344 marker genes. Yet another highlight of the server is the repository of the modeled 11 O- and 79 K- antigen 3D structures.
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Affiliation(s)
- L Ponoop Prasad Patro
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Karpagam Uma Sudhakar
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
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13
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Novel Insights and Features of the NDM-5-Producing Escherichia coli Sequence Type 167 High-Risk Clone. mSphere 2020; 5:5/2/e00269-20. [PMID: 32350092 PMCID: PMC7193042 DOI: 10.1128/msphere.00269-20] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Escherichia coli sequence type 167 (ST167), producing the metallo beta-lactamase NDM-5, has been isolated as a colonizer of patients recovered at the University Hospital Policlinico Umberto I of Rome. Phylogenesis and comparative analysis of the genomes of these strains were performed against 343 ST167 genomes available from the EnteroBase database. These analyses revealed that resistance plasmids, integrative conjugative elements (ICEs), carrying the yersiniabactin virulence trait and capsular synthesis gene clusters had variable compositions and distributions within different strains of the ST167 clone. A novel capsular synthesis gene cluster, highly similar to the K48 cluster previously described only for Klebsiella pneumoniae, was identified in phylogenetically related strains of the ST167 clone.IMPORTANCE Global dissemination of some E. coli high-risk clones has been described in the last decades. The most widespread was the ST131 clone, associated with extended-spectrum-beta-lactamase (ESBL) production. Genomics of ST131 demonstrated that one clade within the ST emerged in the early 2000s, followed by a rapid, global expansion. The E. coli ST167 clone is emerging throughout the world, being frequently reported for its association with carbapenem resistance. Our study shows that virulence features are differently represented within the ST167 population. One clade shows the K48 capsular synthesis gene cluster of K. pneumoniae, not previously described for E. coli, and is populated by NDM-5-producing strains. The combination of resistance and virulence may sustain the global expansion of this specific ST167 clade.
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14
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Grijalva-Hernández F, Vega-Estrada J, Escobar-Rosales M, Ortega-López J, Aguilar-López R, Lara AR, Montes-Horcasitas MDC. High Kanamycin Concentration as Another Stress Factor Additional to Temperature to Increase pDNA Production in E. coli DH5α Batch and Fed-Batch Cultures. Microorganisms 2019; 7:E711. [PMID: 31861108 PMCID: PMC6955755 DOI: 10.3390/microorganisms7120711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/02/2019] [Accepted: 12/13/2019] [Indexed: 02/03/2023] Open
Abstract
Plasmid DNA (pDNA) vaccines require high supercoiled-pDNA doses (milligrams) to achieve an adequate immune response. Therefore, processes development to obtain high pDNA yields and productivity is crucial. pDNA production is affected by several factors including culture type, medium composition, and growth conditions. We evaluated the effect of kanamycin concentration and temperature on pDNA production, overflow metabolism (organic acids) and metabolic burden (neomycin phosphotransferase II) in batch and fed-batch cultures of Escherichia coli DH5α-pVAX1-NH36. Results indicated that high kanamycin concentration increases the volumetric productivity, volumetric and specific yields of pDNA when batch cultures were carried out at 42 °C, and overflow metabolism reduced but metabolic burden increased. Micrographs taken with a scanning electron microscope (SEM) were analyzed, showing important morphological changes. The high kanamycin concentration (300 mg/L) was evaluated in high cell density culture (50 gDCW/L), which was reached using a fed-batch culture with temperature increase by controlling heating and growth rates. The pDNA volumetric yield and productivity were 759 mg/L and 31.19 mg/L/h, respectively, two-fold greater than the control with a kanamycin concentration of 50 mg/L. A stress-based process simultaneously caused by temperature and high kanamycin concentration can be successfully applied to increase pDNA production.
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Affiliation(s)
- Fernando Grijalva-Hernández
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
| | - Jesús Vega-Estrada
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
| | - Montserrat Escobar-Rosales
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
| | - Jaime Ortega-López
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
| | - Ricardo Aguilar-López
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
| | - Alvaro R. Lara
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa. Av. Vasco de Quiroga 4871, Santa Fe, México City 05348, Mexico;
| | - Ma. del Carmen Montes-Horcasitas
- Departamento de Biotecnología y Bioingeniería. Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN) Av. Instituto Politécnico Nacional No. 2508, Col. San Pedro Zacatenco, México City 07360, Mexico; (F.G.-H.); (J.V.-E.); (M.E.-R.); (J.O.-L.); (R.A.-L.)
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15
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Patro LPP, Rathinavelan T. Targeting the Sugary Armor of Klebsiella Species. Front Cell Infect Microbiol 2019; 9:367. [PMID: 31781512 PMCID: PMC6856556 DOI: 10.3389/fcimb.2019.00367] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 10/09/2019] [Indexed: 12/25/2022] Open
Abstract
The emergence of multidrug-resistant strains of Gram-negative Klebsiella species is an urgent global threat. The World Health Organization has listed Klebsiella pneumoniae as one of the global priority pathogens in critical need of next-generation antibiotics. Compared to other Gram-negative pathogens, K. pneumoniae accumulates a greater diversity of antimicrobial-resistant genes at a higher frequency. The evolution of a hypervirulent phenotype of K. pneumoniae is yet another concern. It has a broad ecological distribution affecting humans, agricultural animals, plants, and aquatic animals. Extracellular polysaccharides of Klebsiella, such as lipopolysaccharides, capsular polysaccharides, and exopolysaccharides, play crucial roles in conferring resistance against the host immune response, as well as in colonization, surface adhesion, and for protection against antibiotics and bacteriophages. These extracellular polysaccharides are major virulent determinants and are highly divergent with respect to their antigenic properties. Wzx/Wzy-, ABC-, and synthase-dependent proteinaceous nano-machineries are involved in the biosynthesis, transport, and cell surface expression of these sugar molecules. Although the proteins involved in the biosynthesis and surface expression of these sugar molecules represent potential drug targets, variation in the amino acid sequences of some of these proteins, in combination with diversity in their sugar composition, poses a major challenge to the design of a universal drug for Klebsiella infections. This review discusses the challenges in universal Klebsiella vaccine and drug development from the perspective of antigen sugar compositions and the proteins involved in extracellular antigen transport.
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16
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Nanayakkara BS, O'Brien CL, Gordon DM. Diversity and distribution of Klebsiella capsules in Escherichia coli. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:107-117. [PMID: 30411512 DOI: 10.1111/1758-2229.12710] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 10/31/2018] [Accepted: 11/03/2018] [Indexed: 06/08/2023]
Abstract
E. coli strains responsible for elevated counts (blooms) in freshwater reservoirs in Australia carry a capsule originating from Klebsiella. The occurrence of Klebsiella capsules in E. coli was about 7% overall and 23 different capsule types were detected. Capsules were observed in strains from phylogroups A, B1 and C, but were absent from phylogroup B2, D, E and F strains. In general, few A, B1 or C lineages were capsule-positive, but when a lineage was encapsulated multiple different capsule types were present. All Klebsiella capsule-positive strains were of serogroups O8, O9 and O89. Regardless of the phylogroup, O9 strains were more likely to be capsule-positive than O8 strains. Given the sequence similarity, it appears that both the capsule region and the O-antigen gene region are transferred to E. coli from Klebsiella as a single block via horizontal gene transfer events. Pan genome analysis indicated that there were only modest differences between encapsulated and non-encapsulated strains belonging to phylogroup A. The possession of a Klebsiella capsule, but not the type of capsule, is likely a key determinant of the bloom status of a strain.
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Affiliation(s)
- Buddhie S Nanayakkara
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
- Department of Botany, Faculty of Science, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Claire L O'Brien
- Medical School, The Australian National University, Canberra, ACT 2601, Australia
- Gastroenterology and Hepatology Unit, Canberra Hospital, Canberra, ACT, Australia
| | - David M Gordon
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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17
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Svetlov D, Shi D, Twentyman J, Nedialkov Y, Rosen DA, Abagyan R, Artsimovitch I. In silico discovery of small molecules that inhibit RfaH recruitment to RNA polymerase. Mol Microbiol 2018; 110:128-142. [PMID: 30069925 DOI: 10.1111/mmi.14093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2018] [Indexed: 02/03/2023]
Abstract
RfaH is required for virulence in several Gram-negative pathogens including Escherichia coli and Klebsiella pneumoniae. Through direct interactions with RNA polymerase (RNAP) and ribosome, RfaH activates the expression of capsule, cell wall and pilus biosynthesis operons by reducing transcription termination and activating translation. While E. coli RfaH has been extensively studied using structural and biochemical approaches, limited data are available for other RfaH homologs. Here we set out to identify small molecule inhibitors of E. coli and K. pneumoniae RfaHs. Results of biochemical and functional assays show that these proteins act similarly, with a notable difference between their interactions with the RNAP β subunit gate loop. We focused on high-affinity RfaH interactions with the RNAP β' subunit clamp helices as a shared target for inhibition. Among the top 10 leads identified by in silico docking using ZINC database, 3 ligands were able to inhibit E. coli RfaH recruitment in vitro. The most potent lead was active against both E. coli and K. pneumoniae RfaHs in vitro. Our results demonstrate the feasibility of identifying RfaH inhibitors using in silico docking and pave the way for rational design of antivirulence therapeutics against antibiotic-resistant pathogens.
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Affiliation(s)
- Dmitri Svetlov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Da Shi
- Department of Chemistry and Biochemistry and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, 92093, USA
| | - Joy Twentyman
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yuri Nedialkov
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - David A Rosen
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ruben Abagyan
- Department of Chemistry and Biochemistry and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, 92093, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA
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18
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Huang YT, Chuang WY, Ho BC, Wu ZY, Kuo RC, Ko M, Liu PY. Comparative genomics reveals diverse capsular polysaccharide synthesis gene clusters in emerging Raoultella planticola. Mem Inst Oswaldo Cruz 2018; 113:e180192. [PMID: 30204830 PMCID: PMC6135345 DOI: 10.1590/0074-02760180192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022] Open
Abstract
Raoultella planticola is an emerging zoonotic pathogen that is associated with rare but life-threatening cases of bacteremia, biliary tract infections, and urinary tract infections. Moreover, increasing antimicrobial resistance in the organism poses a potential threat to public health. In spite of its importance as a human pathogen, the genome of R. planticola remains largely unexplored and little is known about its virulence factors. Although lipopolysaccharides has been detected in R. planticola and implicated in the virulence in earlier studies, the genetic background is unknown. Here, we report the complete genome and comparative analysis of the multidrug-resistant clinical isolate R. planticola GODA. The complete genome sequence of R. planticola GODA was sequenced using single-molecule real-time DNA sequencing. Comparative genomic analysis reveals distinct capsular polysaccharide synthesis gene clusters in R. planticola GODA. In addition, we found blaTEM-57 and multiple transporters related to multidrug resistance. The availability of genomic data in open databases of this emerging zoonotic pathogen, in tandem with our comparative study, provides better understanding of R. planticola and the basis for future work.
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Affiliation(s)
- Yao-Ting Huang
- National Chung Cheng University, Department of Computer Science and Information Engineering, Chia-Yi, Taiwan
| | - Wei-Yao Chuang
- National Chung Cheng University, Department of Computer Science and Information Engineering, Chia-Yi, Taiwan
| | - Bing-Ching Ho
- National Taiwan University Hospital, Department of Clinical Laboratory Sciences and Medical Biotechnology, Taipei, Taiwan
| | - Zong-Yen Wu
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA.,National Chung Hsing University, Department of Veterinary Medicine, Taichung, Taiwan
| | - Rita C Kuo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Mengwei Ko
- University of California, Division of Oral Biology and Oral Medicine, School of Dentistry and Medicine, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Los Angeles, CA, USA
| | - Po-Yu Liu
- Shu-Zen Junior College of Medicine and Management, Department of Nursing, Kaohsiung City, Taiwan.,National Chung Hsing University, College of Life Sciences, Rong Hsing Research Center for Translational Medicine, Taichung, Taiwan.,National Chung Hsing University, PhD Program in Translational Medicine, Taichung, Taiwan.,Taichung Veterans General Hospital, Department of Internal Medicine, Division of Infectious Diseases, Taichung, Taiwan
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19
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Kaptive Web: User-Friendly Capsule and Lipopolysaccharide Serotype Prediction for Klebsiella Genomes. J Clin Microbiol 2018; 56:JCM.00197-18. [PMID: 29618504 PMCID: PMC5971559 DOI: 10.1128/jcm.00197-18] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/28/2018] [Indexed: 11/29/2022] Open
Abstract
As whole-genome sequencing becomes an established component of the microbiologist's toolbox, it is imperative that researchers, clinical microbiologists, and public health professionals have access to genomic analysis tools for the rapid extraction of epidemiologically and clinically relevant information. For the Gram-negative hospital pathogens such as Klebsiella pneumoniae, initial efforts have focused on the detection and surveillance of antimicrobial resistance genes and clones. However, with the resurgence of interest in alternative infection control strategies targeting Klebsiella surface polysaccharides, the ability to extract information about these antigens is increasingly important. Here we present Kaptive Web, an online tool for the rapid typing of Klebsiella K and O loci, which encode the polysaccharide capsule and lipopolysaccharide O antigen, respectively. Kaptive Web enables users to upload and analyze genome assemblies in a web browser. The results can be downloaded in tabular format or explored in detail via the graphical interface, making it accessible for users at all levels of computational expertise. We demonstrate Kaptive Web's utility by analyzing >500 K. pneumoniae genomes. We identify extensive K and O locus diversity among 201 genomes belonging to the carbapenemase-associated clonal group 258 (25 K and 6 O loci). The characterization of a further 309 genomes indicated that such diversity is common among the multidrug-resistant clones and that these loci represent useful epidemiological markers for strain subtyping. These findings reinforce the need for rapid, reliable, and accessible typing methods such as Kaptive Web. Kaptive Web is available for use at http://kaptive.holtlab.net/, and the source code is available at https://github.com/kelwyres/Kaptive-Web.
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20
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Non-capsulated mutants of a chemical-producing Klebsiella pneumoniae strain. Biotechnol Lett 2018; 40:679-687. [PMID: 29429073 DOI: 10.1007/s10529-018-2524-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/30/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To investigate the outcomes of capsule lost on cell transformation efficiency and chemicals (1,3-propanediol, 2,3-butanediol, and 2-ketogluconic acid) production by Klebsiella pneumoniae. RESULTS The cps gene cluster showed low sequence homology with pathogenic strains. The wza is a highly conserved gene in the cps cluster that encodes an outer membrane protein. A non-capsulated mutant was constructed by deletion of wza. Phenotype studies demonstrated that non-capsulated cells were less buoyant and easy to sediment. The transformation efficiency of the non-capsulated mutant reached 6.4 × 105 CFU μg-1 DNA, which is 10 times higher than that of the wild strain. 52.2 g 1,3-propanediol L-1, 30.7 g 2,3-butanediol L-1, and 175.9 g 2-ketogluconic acid L-1 were produced by non-capsulated mutants, which were 10-40% lower compared to wild strain. Furthermore, viscosities of the three fermentation broths decreased to approximately 1.3 cP from the range of 1.8-2.2 cP. CONCLUSIONS Non-capsulated K. pneumoniae mutants should allay concerns regarding biological safety, improve transformation efficiency, lower viscosity, and subsequently ameliorate the financial burden of the downstream process of chemicals production.
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Yang S, Xi D, Jing F, Kong D, Wu J, Feng L, Cao B, Wang L. Genetic diversity of K-antigen gene clusters of Escherichia coli and their molecular typing using a suspension array. Can J Microbiol 2018; 64:231-241. [PMID: 29357266 DOI: 10.1139/cjm-2017-0620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Capsular polysaccharides (CPSs), or K-antigens, are the major surface antigens of Escherichia coli. More than 80 serologically unique K-antigens are classified into 4 groups (Groups 1-4) of capsules. Groups 1 and 4 contain the Wzy-dependent polymerization pathway and the gene clusters are in the order galF to gnd; Groups 2 and 3 contain the ABC-transporter-dependent pathway and the gene clusters consist of 3 regions, regions 1, 2 and 3. Little is known about the variations among the gene clusters. In this study, 9 serotypes of K-antigen gene clusters (K2ab, K11, K20, K24, K38, K84, K92, K96, and K102) were sequenced and correlated with their CPS chemical structures. On the basis of sequence data, a K-antigen-specific suspension array that detects 10 distinct CPSs, including the above 9 CPSs plus K30, was developed. This is the first report to catalog the genetic features of E. coli K-antigen variations and to develop a suspension array for their molecular typing. The method has a number of advantages over traditional bacteriophage and serum agglutination methods and lays the foundation for straightforward identification and detection of additional K-antigens in the future.
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Affiliation(s)
- Shuang Yang
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Daoyi Xi
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Fuyi Jing
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Deju Kong
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Junli Wu
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Lu Feng
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Boyang Cao
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Lei Wang
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
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Catalán-Nájera JC, Garza-Ramos U, Barrios-Camacho H. Hypervirulence and hypermucoviscosity: Two different but complementary Klebsiella spp. phenotypes? Virulence 2017; 8:1111-1123. [PMID: 28402698 DOI: 10.1080/21505594.2017.1317412] [Citation(s) in RCA: 201] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Since the hypermucoviscous variants of Klebsiella pneumoniae were first reported, many cases of primary liver abscesses and other invasive infections caused by this pathogen have been described worldwide. Hypermucoviscosity is a phenotypic feature characterized by the formation of a viscous filament ≥5 mm when a bacterial colony is stretched by a bacteriological loop; this is the so-called positive string test. Hypermucoviscosity appears to be associated with this unusual and aggressive type of infection, and therefore, the causal strains are considered hypervirulent. Since these first reports, the terms hypermucoviscosity and hypervirulence have often been used synonymously. However, new evidence has suggested that hypermucoviscosity and hypervirulence are 2 different phenotypes that should not be used synonymously. Moreover, it is important to establish that a negative string test is insufficient in determining whether a strain is or is not hypervirulent. On the other hand, hypervirulence- and hypermucoviscosity-associated genes must be identified, considering that these phenotypes correspond to 2 different phenomena, regardless of whether they can act in synergy under certain circumstances. Therefore, it is essential to quickly identify the genetic determinants behind the hypervirulent phenotype to develop effective methodologies that can diagnose in a prompt and effective way these hypervirulent variants of K. pneumoniae.
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Affiliation(s)
- Juan Carlos Catalán-Nájera
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
| | - Ulises Garza-Ramos
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
| | - Humberto Barrios-Camacho
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
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23
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Sachdeva S, Palur RV, Sudhakar KU, Rathinavelan T. E. coli Group 1 Capsular Polysaccharide Exportation Nanomachinary as a Plausible Antivirulence Target in the Perspective of Emerging Antimicrobial Resistance. Front Microbiol 2017; 8:70. [PMID: 28217109 PMCID: PMC5290995 DOI: 10.3389/fmicb.2017.00070] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/11/2017] [Indexed: 02/02/2023] Open
Abstract
Bacteria evolving resistance against the action of multiple drugs and its ability to disseminate the multidrug resistance trait(s) across various strains of the same bacteria or different bacterial species impose serious threat to public health. Evolution of such multidrug resistance is due to the fact that, most of the antibiotics target bacterial survival mechanisms which exert selective pressure on the bacteria and aids them to escape from the action of antibiotics. Nonetheless, targeting bacterial virulence strategies such as bacterial surface associated polysaccharides biosynthesis and their surface accumulation mechanisms may be an attractive strategy, as they impose less selective pressure on the bacteria. Capsular polysaccharide (CPS) or K-antigen that is located on the bacterial surface armors bacteria from host immune response. Thus, unencapsulating bacteria would be a good strategy for drug design, besides CPS itself being a good vaccine target, by interfering with CPS biosynthesis and surface assembly pathway. Gram-negative Escherichia coli uses Wzy-polymerase dependent (Groups 1 and 4) and ATP dependent (Groups 1 and 3) pathways for CPS production. Considering E. coli as a case in point, this review explains the structure and functional roles of proteins involved in Group 1 Wzy dependent CPS biosynthesis, surface expression and anchorage in relevance to drug and vaccine developments.
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Affiliation(s)
- Shivangi Sachdeva
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
| | - Raghuvamsi V Palur
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
| | - Karpagam U Sudhakar
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
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24
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Wyres KL, Wick RR, Gorrie C, Jenney A, Follador R, Thomson NR, Holt KE. Identification of Klebsiella capsule synthesis loci from whole genome data. Microb Genom 2016; 2:e000102. [PMID: 28348840 PMCID: PMC5359410 DOI: 10.1099/mgen.0.000102] [Citation(s) in RCA: 263] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/06/2016] [Indexed: 12/14/2022] Open
Abstract
Klebsiella pneumoniae is a growing cause of healthcare-associated infections for which multi-drug resistance is a concern. Its polysaccharide capsule is a major virulence determinant and epidemiological marker. However, little is known about capsule epidemiology since serological typing is not widely accessible and many isolates are serologically non-typeable. Molecular typing techniques provide useful insights, but existing methods fail to take full advantage of the information in whole genome sequences. We investigated the diversity of the capsule synthesis loci (K-loci) among 2503 K. pneumoniae genomes. We incorporated analyses of full-length K-locus nucleotide sequences and also clustered protein-encoding sequences to identify, annotate and compare K-locus structures. We propose a standardized nomenclature for K-loci and present a curated reference database. A total of 134 distinct K-loci were identified, including 31 novel types. Comparative analyses indicated 508 unique protein-encoding gene clusters that appear to reassort via homologous recombination. Extensive intra- and inter-locus nucleotide diversity was detected among the wzi and wzc genes, indicating that current molecular typing schemes based on these genes are inadequate. As a solution, we introduce Kaptive, a novel software tool that automates the process of identifying K-loci based on full locus information extracted from whole genome sequences (https://github.com/katholt/Kaptive). This work highlights the extensive diversity of Klebsiella K-loci and the proteins that they encode. The nomenclature, reference database and novel typing method presented here will become essential resources for genomic surveillance and epidemiological investigations of this pathogen.
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Affiliation(s)
- Kelly L. Wyres
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Ryan R. Wick
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Claire Gorrie
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Adam Jenney
- Infectious Diseases and Microbiology Unit, The Alfred Hospital, Melbourne, Australia
| | | | - Nicholas R. Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Kathryn E. Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
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25
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Follador R, Heinz E, Wyres KL, Ellington MJ, Kowarik M, Holt KE, Thomson NR. The diversity of Klebsiella pneumoniae surface polysaccharides. Microb Genom 2016; 2:e000073. [PMID: 28348868 PMCID: PMC5320592 DOI: 10.1099/mgen.0.000073] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/09/2016] [Indexed: 11/24/2022] Open
Abstract
Klebsiella pneumoniae is considered an urgent health concern due to the emergence of multi-drug-resistant strains for which vaccination offers a potential remedy. Vaccines based on surface polysaccharides are highly promising but need to address the high diversity of surface-exposed polysaccharides, synthesized as O-antigens (lipopolysaccharide, LPS) and K-antigens (capsule polysaccharide, CPS), present in K. pneumoniae. We present a comprehensive and clinically relevant study of the diversity of O- and K-antigen biosynthesis gene clusters across a global collection of over 500 K. pneumoniae whole-genome sequences and the seroepidemiology of human isolates from different infection types. Our study defines the genetic diversity of O- and K-antigen biosynthesis cluster sequences across this collection, identifying sequences for known serotypes as well as identifying novel LPS and CPS gene clusters found in circulating contemporary isolates. Serotypes O1, O2 and O3 were most prevalent in our sample set, accounting for approximately 80 % of all infections. In contrast, K serotypes showed an order of magnitude higher diversity and differ among infection types. In addition we investigated a potential association of O or K serotypes with phylogenetic lineage, infection type and the presence of known virulence genes. K1 and K2 serotypes, which are associated with hypervirulent K. pneumoniae, were associated with a higher abundance of virulence genes and more diverse O serotypes compared to other common K serotypes.
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Affiliation(s)
| | - Eva Heinz
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Kelly L. Wyres
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | | | | | - Kathryn E. Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Nicholas R. Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
- London School of Hygiene and Tropical Medicine, London, UK
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26
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Abstract
Klebsiella pneumoniae causes a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically, K. pneumoniae has caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore, K. pneumoniae strains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity in K. pneumoniae strains, and not every factor plays the same critical role in all virulent Klebsiella strains. Recent studies have identified additional K. pneumoniae virulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.
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27
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Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp. Sci Rep 2015; 5:15573. [PMID: 26493302 PMCID: PMC4616057 DOI: 10.1038/srep15573] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 09/28/2015] [Indexed: 11/15/2022] Open
Abstract
A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types. Accordingly, wzy-based capsular genotyping could differentiate capsule types except for those lacking wzy (K29 and K50), those sharing identical wzy (K22 vs. K37); and should be carefully applied in those exhibited high similarity (K12 vs. K41, K2 vs. K13, K74 vs. K80, K79 vs. KN1 and K30 vs. K69). Comparison of CPS structures in several capsular types that shared similarity in their gene contents implies possible functions of glycosyltransferases. Therefore, our results provide complete set of cps in various types of Klebsiella spp., which enable the understandings of relationship between genes and CPS structures and are useful for identification of documented or new capsular types.
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28
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Li B, Zhao Y, Liu C, Chen Z, Zhou D. Molecular pathogenesis of Klebsiella pneumoniae. Future Microbiol 2015; 9:1071-81. [PMID: 25340836 DOI: 10.2217/fmb.14.48] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Typical Klebsiella pneumoniae is an opportunistic pathogen, which mostly affects those with weakened immune systems and tends to cause nosocomial infections. A subset of hypervirulent K. pneumoniae serotypes with elevated production of capsule polysaccharide can affect previously healthy persons and cause life-threatening community-acquired infections, such as pyogenic liver abscess, meningitis, necrotizing fasciitis, endophthalmitis and severe pneumonia. K. pneumoniae utilizes a variety of virulence factors, especially capsule polysaccharide, lipopolysaccharide, fimbriae, outer membrane proteins and determinants for iron acquisition and nitrogen source utilization, for survival and immune evasion during infection. This article aims to present the state-of-the-art understanding of the molecular pathogenesis of K. pneumoniae.
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Affiliation(s)
- Bei Li
- Department of Dermatology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, China
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29
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Wyres KL, Gorrie C, Edwards DJ, Wertheim HFL, Hsu LY, Van Kinh N, Zadoks R, Baker S, Holt KE. Extensive Capsule Locus Variation and Large-Scale Genomic Recombination within the Klebsiella pneumoniae Clonal Group 258. Genome Biol Evol 2015; 7:1267-79. [PMID: 25861820 PMCID: PMC4453057 DOI: 10.1093/gbe/evv062] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Klebsiella pneumoniae clonal group (CG) 258, comprising sequence types (STs) 258, 11, and closely related variants, is associated with dissemination of the K. pneumoniae carbapenemase (KPC). Hospital outbreaks of KPC CG258 infections have been observed globally and are very difficult to treat. As a consequence, there is renewed interest in alternative infection control measures such as vaccines and phage or depolymerase treatments targeting the K. pneumoniae polysaccharide capsule. To date, 78 immunologically distinct capsule variants have been described in K. pneumoniae. Previous investigations of ST258 and a small number of closely related strains suggested that capsular variation was limited within this clone; only two distinct ST258 capsule polysaccharide synthesis (cps) loci have been identified, both acquired through large-scale recombination events (>50 kb). In contrast to previous studies, we report a comparative genomic analysis of the broader K. pneumoniae CG258 (n = 39). We identified 11 different cps loci within CG258, indicating that capsular switching is actually common within the complex. We observed several insertion sequences (IS) within the cps loci, and show further intraclone diversification of two cps loci through IS activity. Our data also indicate that several large-scale recombination events have shaped the genomes of CG258, and that definition of the complex should be broadened to include ST395 (also reported to harbor KPC). As only the second report of extensive intraclonal cps variation among Gram-negative bacterial species, our findings alter our understanding of the evolution of these organisms and have key implications for the design of control measures targeting K. pneumoniae capsules.
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Affiliation(s)
- Kelly L Wyres
- IBM Research-Australia, Carlton, Victoria, Australia Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Claire Gorrie
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - David J Edwards
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Heiman F L Wertheim
- Wellcome Trust Major Overseas Programme, Clinical Research Unit, Oxford University Hanoi, Vietnam Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Li Yang Hsu
- National Hospital for Tropical Diseases, Hanoi, Vietnam
| | - Nguyen Van Kinh
- Wellcome Trust Major Overseas Programme, Clinical Research Unit, Oxford University Hanoi, Vietnam Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Ruth Zadoks
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian, United Kingdom
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, United Kingdom The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kathryn E Holt
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
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30
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Genome sequence of Vibrio diabolicus and identification of the exopolysaccharide HE800 biosynthesis locus. Appl Microbiol Biotechnol 2014; 98:10165-76. [PMID: 25273176 DOI: 10.1007/s00253-014-6086-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 09/01/2014] [Accepted: 09/03/2014] [Indexed: 01/08/2023]
Abstract
Vibrio diabolicus, a marine bacterium originating from deep-sea hydrothermal vents, produces the HE800 exopolysaccharide with high value for biotechnological purposes, especially for human health. Its genome was sequenced and analyzed; phylogenetic analysis using the core genome revealed V. diabolicus is close to another deep-sea Vibrio sp. (Ex25) within the Harveyi clade and Alginolyticus group. A genetic locus homologous to the syp cluster from Vibrio fischeri was demonstrated to be involved in the HE800 production. However, few genetic particularities suggest that the regulation of syp expression may be different in V. diabolicus. The presence of several types of glycosyltransferases within the locus indicates a capacity to generate diversity in the glycosidic structure, which may confer an adaptability to environmental conditions. These results contribute to better understanding exopolysaccharide biosynthesis and for developing new efficient processes to produce this molecule for biotechnological applications.
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31
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D’Andrea MM, Amisano F, Giani T, Conte V, Ciacci N, Ambretti S, Santoriello L, Rossolini GM. Diversity of capsular polysaccharide gene clusters in Kpc-producing Klebsiella pneumoniae clinical isolates of sequence type 258 involved in the Italian epidemic. PLoS One 2014; 9:e96827. [PMID: 24823690 PMCID: PMC4019520 DOI: 10.1371/journal.pone.0096827] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 04/11/2014] [Indexed: 01/28/2023] Open
Abstract
Strains of Klebsiella pneumoniae producing KPC-type beta-lactamases (KPC-Kp) are broadly disseminating worldwide and constitute a major healthcare threat given their extensively drug resistant phenotypes and ability to rapidly disseminate in healthcare settings. In this work we report on the characterization of two different capsular polysaccharide (CPS) gene clusters, named cpsBO-4 and cps207-2, from two KPC-Kp clinical strains from Italy belonging in sequence type (ST) 258, which is one of the most successful ST of KPC-Kp spreading worldwide. While cpsBO-4 was different from known 78 K-types according to the recently proposed typing schemes based on the wzi or wzc gene sequences, cps207-2 was classified as K41 by one of these methods. Bioinformatic analysis revealed that they were represented in the genomic sequences of KPC-Kp from strains of ST258 from different countries, and cpsBO-4 was also detected in a KPC-Kp strain of ST442 from Brazil. Investigation of a collection of 46 ST258 and ST512 (a single locus variant of ST258) clinical strains representative of the recent Italian epidemic of KPC-Kp by means of a multiplex PCR typing approach revealed that cpsBO-4 was the most prevalent type, being detected both in ST258 and ST512 strains with a countrywide distribution, while cps207-2 was only detected in ST258 strains with a more restricted distribution.
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Affiliation(s)
| | - Francesco Amisano
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Tommaso Giani
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Viola Conte
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Nagaia Ciacci
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Simone Ambretti
- Operative Unit of Clinical Microbiology, St. Orsola-Malpighi University Hospital, Bologna, Italy
| | | | - Gian Maria Rossolini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
- Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy
- * E-mail:
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32
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Pan YJ, Lin TL, Chen YH, Hsu CR, Hsieh PF, Wu MC, Wang JT. Capsular types of Klebsiella pneumoniae revisited by wzc sequencing. PLoS One 2013; 8:e80670. [PMID: 24349011 PMCID: PMC3857182 DOI: 10.1371/journal.pone.0080670] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 10/05/2013] [Indexed: 01/03/2023] Open
Abstract
Capsule is an important virulence factor in bacteria. A total of 78 capsular types have been identified in Klebsiella pneumoniae. However, there are limitations in current typing methods. We report here the development of a new genotyping method based on amplification of the variable regions of the wzc gene. Fragments corresponding to the variable region of wzc were amplified and sequenced from 76 documented capsular types of reference or clinical strains. The remaining two capsular types (reference strains K15 and K50) lacked amplifiable wzc genes and were proven to be acapsular. Strains with the same capsular type exhibited ≧94% DNA sequence identity across the variable region (CD1-VR2-CD2) of wzc. Strains with distinct K types exhibited <80% DNA sequence identity across this region, with the exception of three pairs of strains: K22/K37, K9/K45, and K52/K79. Strains K22 and K37 shared identical capsular polysaccharide synthesis (cps) genes except for one gene with a difference at a single base which resulted in frameshift mutation. The wzc sequences of K9 and K45 exhibited high DNA sequence similarity but possessed different genes in their cps clusters. K52 and K79 exhibited 89% wzc DNA sequence identity but were readily distinguished from each other at the DNA level; in contrast, strains with the same capsular type as K52 exhibited 100% wzc sequence identity. A total of 29 strains from patients with bacteremia were typed by the wzc system. wzc DNA sequences confirmed the documented capsular type for twenty-eight of these clinical isolates; the remaining strain likely represents a new capsular type. Thus, the wzc genotyping system is a simple and useful method for capsular typing of K. pneumoniae.
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Affiliation(s)
- Yi-Jiun Pan
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Tzu-Lung Lin
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yen-Hua Chen
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chun-Ru Hsu
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Pei-Fang Hsieh
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Meng-Chuan Wu
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jin-Town Wang
- Department of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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wzi Gene sequencing, a rapid method for determination of capsular type for Klebsiella strains. J Clin Microbiol 2013; 51:4073-8. [PMID: 24088853 DOI: 10.1128/jcm.01924-13] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pathogens of the genus Klebsiella have been classified into distinct capsular (K) types for nearly a century. K typing of Klebsiella species still has important applications in epidemiology and clinical microbiology, but the serological method has strong practical limitations. Our objective was to evaluate the sequencing of wzi, a gene conserved in all capsular types of Klebsiella pneumoniae that codes for an outer membrane protein involved in capsule attachment to the cell surface, as a simple and rapid method for the prediction of K type. The sequencing of a 447-nucleotide region of wzi distinguished the K-type reference strains with only nine exceptions. A reference wzi sequence database was created by the inclusion of multiple strains representing K types associated with high virulence and multidrug resistance. A collection of 119 prospective clinical isolates of K. pneumoniae were then analyzed in parallel by wzi sequencing and classical K typing. Whereas K typing achieved typeability for 81% and discrimination for 94.4% of the isolates, these figures were 98.1% and 98.3%, respectively, for wzi sequencing. The prediction of K type once the wzi allele was known was 94%. wzi sequencing is a rapid and simple method for the determination of the K types of most K. pneumoniae clinical isolates.
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Alvarez LAJ, Bourke B, Pircalabioru G, Georgiev AY, Knaus UG, Daff S, Corcionivoschi N. Cj1411c encodes for a cytochrome P450 involved in Campylobacter jejuni 81-176 pathogenicity. PLoS One 2013; 8:e75534. [PMID: 24086558 PMCID: PMC3784454 DOI: 10.1371/journal.pone.0075534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 08/14/2013] [Indexed: 11/25/2022] Open
Abstract
Cytochrome P450s are b-heme-containing enzymes that are able to introduce oxygen atoms into a wide variety of organic substrates. They are extremely widespread in nature having diverse functions at both biochemical and physiological level. The genome of C. jejuni 81-176 encodes a single cytochrome P450 (Cj1411c) that has no close homologues. Cj1411c is unusual in its genomic location within a cluster involved in the biosynthesis of outer surface structures. Here we show that E. coli expressed and affinity-purified C. jejuni cytochrome P450 is lipophilic, containing one equivalent Cys-ligated heme. Immunoblotting confirmed the association of cytochrome P450 with membrane fractions. A Cj1411c deletion mutant had significantly reduced ability to infect human cells and was less able to survive following exposure to human serum when compared to the wild type strain. Phenotypically following staining with Alcian blue, we show that a Cj1411c deletion mutant produces significantly less capsular polysaccharide. This study describes the first known membrane-bound bacterial cytochrome P450 and its involvement in Campylobacter virulence.
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Affiliation(s)
- Luis A. J. Alvarez
- National Children’s Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland
| | - Billy Bourke
- National Children’s Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland
- Conway Institute, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Gratiela Pircalabioru
- Conway Institute, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Atanas Y. Georgiev
- School of Chemistry, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Ulla G. Knaus
- National Children’s Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland
- Conway Institute, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Simon Daff
- School of Chemistry, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Nicolae Corcionivoschi
- National Children’s Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland
- Banat’s University of Agricultural Sciences and Veterinary Medicine, School of Animal Sciences and Biotechnology, Timişoara, Romania
- * E-mail:
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Gene content and diversity of the loci encoding biosynthesis of capsular polysaccharides of the 15 serovar reference strains of Haemophilus parasuis. J Bacteriol 2013; 195:4264-73. [PMID: 23873912 DOI: 10.1128/jb.00471-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Haemophilus parasuis is the causative agent of Glässer's disease, a systemic disease of pigs, and is also associated with pneumonia. H. parasuis can be classified into 15 different serovars. Here we report, from the 15 serotyping reference strains, the DNA sequences of the loci containing genes for the biosynthesis of the group 1 capsular polysaccharides, which are potential virulence factors of this bacterium. We contend that these loci contain genes for polysaccharide capsule structures, and not a lipopolysaccharide O antigen, supported by the fact that they contain genes such as wza, wzb, and wzc, which are associated with the export of polysaccharide capsules in the current capsule classification system. A conserved region at the 3' end of the locus, containing the wza, ptp, wzs, and iscR genes, is consistent with the characteristic export region 1 of the model group 1 capsule locus. A potential serovar-specific region (region 2) has been found by comparing the predicted coding sequences (CDSs) in all 15 loci for synteny and homology. The region is unique to each reference strain with the exception of those in serovars 5 and 12, which are identical in terms of gene content. The identification and characterization of this locus among the 15 serovars is the first step in understanding the genetic, molecular, and structural bases of serovar specificity in this poorly studied but important pathogen and opens up the possibility of developing an improved molecular serotyping system, which would greatly assist diagnosis and control of Glässer's disease.
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Reeves PR, Cunneen MM, Liu B, Wang L. Genetics and evolution of the Salmonella galactose-initiated set of o antigens. PLoS One 2013; 8:e69306. [PMID: 23874940 PMCID: PMC3715488 DOI: 10.1371/journal.pone.0069306] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 06/09/2013] [Indexed: 11/18/2022] Open
Abstract
This paper covers eight Salmonella serogroups, that are defined by O antigens with related structures and gene clusters. They include the serovars that are now most frequently isolated. Serogroups A, B1, B2, C2-C3, D1, D2, D3 and E have O antigens that are distinguished by having galactose as first sugar, and not N-acetyl glucosamine or N-acetyl galactosamine as in the other 38 serogroups, and indeed in most Enterobacteriaceae. The gene clusters for these galactose-initiated appear to have entered S. enterica since its divergence from E. coli, but sequence comparisons show that much of the diversification occurred long before this. We conclude that the gene clusters must have entered S. enterica in a series of parallel events. The individual gene clusters are discussed, followed by analysis of the divergence for those genes shared by two or more gene clusters, and a putative phylogenic tree for the gene clusters is presented. This set of O antigens provides a rare case where it is possible to examine in detail the relationships of a significant number of O antigens. In contrast the more common pattern of O-antigen diversity within a species is for there to be only a few cases of strains having related gene clusters, suggesting that diversity arose through gain of individual O-antigen gene clusters by lateral gene transfer, and under these circumstances the evolution of the diversity is not accessible. This paper on the galactose-initiated set of gene clusters gives new insights into the origins of O-antigen diversity generally.
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Affiliation(s)
- Peter R Reeves
- School of Molecular Bioscience, University of Sydney, Sydney, Australia.
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Mainprize IL, Bean JD, Bouwman C, Kimber MS, Whitfield C. The UDP-glucose dehydrogenase of Escherichia coli K-12 displays substrate inhibition by NAD that is relieved by nucleotide triphosphates. J Biol Chem 2013; 288:23064-74. [PMID: 23792965 DOI: 10.1074/jbc.m113.486613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
UDP-glucose dehydrogenase (Ugd) generates UDP-glucuronic acid, an important precursor for the production of many hexuronic acid-containing bacterial surface glycostructures. In Escherichia coli K-12, Ugd is important for biosynthesis of the environmentally regulated exopolysaccharide known as colanic acid, whereas in other E. coli isolates, the same enzyme is required for production of the constitutive group 1 capsular polysaccharides, which act as virulence determinants. Recent studies have implicated tyrosine phosphorylation in the activation of Ugd from E. coli K-12, although it is not known if this is a feature shared by bacterial Ugd proteins. The activities of Ugd from E. coli K-12 and from the group 1 capsule prototype (serotype K30) were compared. Surprisingly, for both enzymes, site-directed Tyr → Phe mutants affecting the previously proposed phosphorylation site retained similar kinetic properties to the wild-type protein. Purified Ugd from E. coli K-12 had significant levels of NAD substrate inhibition, which could be alleviated by the addition of ATP and several other nucleotide triphosphates. Mutations in a previously identified UDP-glucuronic acid allosteric binding site decreased the binding affinity of the nucleotide triphosphate. Ugd from E. coli serotype K30 was not inhibited by NAD, but its activity still increased in the presence of ATP.
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Affiliation(s)
- Iain L Mainprize
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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A colanic acid operon deletion mutation enhances induction of early antibody responses by live attenuated Salmonella vaccine strains. Infect Immun 2013; 81:3148-62. [PMID: 23774599 DOI: 10.1128/iai.00097-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Colanic acid (CA) is a common exopolysaccharide produced by many genera in the Enterobacteriaceae. It is critical for biofilm formation on HEp-2 cells and on chicken intestinal tissue by Salmonella. In this study, we generated different CA synthesis gene mutants and evaluated the immune responses induced by these mutants. One of these mutations, Δ(wza-wcaM)8, which deleted the whole operon for CA synthesis, was introduced into two Salmonella vaccine strains attenuated by auxotrophic traits or by the regulated delayed attenuation strategy (RDAS). The mice immunized with the auxotrophic Salmonella vaccine strain with the deletion mutation Δ(wza-wcaM)8 developed higher vaginal IgA titers against the heterologous protective antigen and higher levels of antigen-specific IgA secretion cells in lungs. In Salmonella vaccine strains with RDAS, the strain with the Δ(wza-wcaM)8 mutation resulted in higher levels of protective antigen production during in vitro growth. Mice immunized with this strain developed higher serum IgG and mucosal IgA antibody responses at 2 weeks. This strain also resulted in better gamma interferon (IFN-γ) responses than the strain without this deletion at doses of 10(8) and 10(9) CFU. Thus, the mutation Δ(wza-wcaM)8 will be included in various recombinant attenuated Salmonella vaccine (RASV) strains with RDAS derived from Salmonella enterica serovar Paratyphi A and Salmonella enterica serovar Typhi to induce protective immunity against bacterial pathogens.
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Willis LM, Whitfield C. Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways. Carbohydr Res 2013; 378:35-44. [PMID: 23746650 DOI: 10.1016/j.carres.2013.05.007] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/06/2013] [Accepted: 05/11/2013] [Indexed: 12/11/2022]
Abstract
Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.
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Affiliation(s)
- Lisa M Willis
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Bushell S, Mainprize I, Wear M, Lou H, Whitfield C, Naismith J. Wzi is an outer membrane lectin that underpins group 1 capsule assembly in Escherichia coli. Structure 2013; 21:844-53. [PMID: 23623732 PMCID: PMC3791409 DOI: 10.1016/j.str.2013.03.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 12/12/2022]
Abstract
Many pathogenic bacteria encase themselves in a polysaccharide capsule that provides a barrier to the physical and immunological challenges of the host. The mechanism by which the capsule assembles around the bacterial cell is unknown. Wzi, an integral outer-membrane protein from Escherichia coli, has been implicated in the formation of group 1 capsules. The 2.6 Å resolution structure of Wzi reveals an 18-stranded β-barrel fold with a novel arrangement of long extracellular loops that blocks the extracellular entrance and a helical bundle that plugs the periplasmic end. Mutagenesis shows that specific extracellular loops are required for in vivo capsule assembly. The data show that Wzi binds the K30 carbohydrate polymer and, crucially, that mutants functionally deficient in vivo show no binding to K30 polymer in vitro. We conclude that Wzi is a novel outer-membrane lectin that assists in the formation of the bacterial capsule via direct interaction with capsular polysaccharides.
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Affiliation(s)
- Simon R. Bushell
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Iain L. Mainprize
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Martin A. Wear
- School of Chemistry, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JJ, UK
| | - Hubing Lou
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Chris Whitfield
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - James H. Naismith
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, KY16 9ST, UK
- Corresponding author
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41
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Ramos PIP, Picão RC, Vespero EC, Pelisson M, Zuleta LFG, Almeida LGP, Gerber AL, Vasconcelos ATR, Gales AC, Nicolás MF. Pyrosequencing-based analysis reveals a novel capsular gene cluster in a KPC-producing Klebsiella pneumoniae clinical isolate identified in Brazil. BMC Microbiol 2012; 12:173. [PMID: 22882772 PMCID: PMC3438125 DOI: 10.1186/1471-2180-12-173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/23/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND An important virulence factor of Klebsiella pneumoniae is the production of capsular polysaccharide (CPS), a thick mucus layer that allows for evasion of the host's defense and creates a barrier against antibacterial peptides. CPS production is driven mostly by the expression of genes located in a locus called cps, and the resulting structure is used to distinguish between different serotypes (K types). In this study, we report the unique genetic organization of the cps cluster from K. pneumoniae Kp13, a clinical isolate recovered during a large outbreak of nosocomial infections that occurred in a Brazilian teaching hospital. RESULTS A pyrosequencing-based approach showed that the cps region of Kp13 (cpsKp13) is 26.4 kbp in length and contains genes common, although not universal, to other strains, such as the rmlBADC operon that codes for L-rhamnose synthesis. cpsKp13 also presents some unique features, like the inversion of the wzy gene and a unique repertoire of glycosyltransferases. In silico comparison of cpsKp13 RFLP pattern with 102 previously published cps PCR-RFLP patterns showed that cpsKp13 is distinct from the C patterns of all other K serotypes. Furthermore, in vitro serotyping showed only a weak reaction with capsular types K9 and K34. We confirm that K9 cps shares common genes with cpsKp13 such as the rmlBADC operon, but lacks features like uge and Kp13-specific glycosyltransferases, while K34 capsules contain three of the five sugars that potentially form the Kp13 CPS. CONCLUSIONS We report the first description of a cps cluster from a Brazilian clinical isolate of a KPC-producing K. pneumoniae. The gathered data including K-serotyping support that Kp13's K-antigen belongs to a novel capsular serotype. The CPS of Kp13 probably includes L-rhamnose and D-galacturonate in its structure, among other residues. Because genes involved in L-rhamnose biosynthesis are absent in humans, this pathway may represent potential targets for the development of antimicrobial agents. Studying the capsular serotypes of clinical isolates is of great importance for further development of vaccines and/or novel therapeutic agents. The distribution of K-types among multidrug-resistant isolates is unknown, but our findings may encourage scientists to perform K-antigen typing of KPC-producing strains worldwide.
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Liu B, Chen M, Perepelov AV, Liu J, Ovchinnikova OG, Zhou D, Feng L, Rozalski A, Knirel YA, Wang L. Genetic analysis of the O-antigen of Providencia alcalifaciens O30 and biochemical characterization of a formyltransferase involved in the synthesis of a Qui4N derivative. Glycobiology 2012; 22:1236-44. [PMID: 22661447 DOI: 10.1093/glycob/cws089] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
O-Antigen is a component of the outer membrane of Gram-negative bacteria and one of the most variable cell surface constituents, giving rise to major antigenic variability. The diversity of O-antigen is almost entirely attributed to genetic variations in O-antigen gene clusters. Bacteria of the genus Providencia are facultative pathogens, which can cause urinary tract infections, wound infections and enteric diseases. Recently, the O-antigen gene cluster of Providencia was localized between the cpxA and yibK genes in the genome. However, few genes involved in the synthesis of Providencia O-antigens have been functionally identified. In this study, the putative O-antigen gene cluster of Providencia alcalifaciens O30 was sequenced and analyzed. Almost all putative genes for the O-antigen synthesis were found, including a novel formyltransferase gene vioF that was proposed to be responsible for the conversion of dTDP-4-amino-4,6- dideoxy-D-glucose (dTDP-D-Qui4N) to dTDP-4,6-dideoxy-4-formamido-D-glucose (dTDP-D-Qui4NFo). vioF was cloned, and the enzyme product was expressed as a His-tagged fusion protein, purified and assayed for its activity. High-performance liquid chromatography was used to monitor the enzyme-substrate reaction, and the structure of the product dTDP-D-Qui4NFo was established by electrospray ionization tandem mass spectrometry and nuclear magnetic resonance spectroscopy. Kinetic parameters of VioF were determined, and effects of temperature and cations on its activity were also examined. Together, the functional analyses support the identification of the O-antigen gene cluster of P. alcalifaciens O30.
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Affiliation(s)
- Bin Liu
- TEDA School of Biological Sciences and Biotechnology, Tianjin, PR China
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Role of the vpe carbohydrate permease in Escherichia coli urovirulence and fitness in vivo. Infect Immun 2012; 80:2655-66. [PMID: 22615242 DOI: 10.1128/iai.00457-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) strains are a leading cause of infections in humans, but the mechanisms governing host colonization by this bacterium remain poorly understood. Previous studies have identified numerous gene clusters encoding proteins involved in sugar transport, in pathogen-specific islands. We investigated the role in fitness and virulence of the vpe operon encoding an EII complex of the phosphotransferase (PTS) system, which is found more frequently in human strains from infected urine and blood (45%) than in E. coli isolated from healthy humans (15%). We studied the role of this locus in vivo, using the UPEC E. coli strain AL511, mutants, and complemented derivatives in two experimental mouse models of infection. Mutant strains displayed attenuated virulence in a mouse model of sepsis. A role in kidney colonization was also demonstrated by coinfection experiments in a mouse model of pyelonephritis. Electron microscopy examinations showed that the vpeBC mutant produced much smaller amounts of a capsule-like surface material than the wild type, particularly when growing in human urine. Complementation of the vpeBC mutation led to an increase in the amount of exopolysaccharide, resistance to serum killing, and virulence. It was therefore clear that the loss of vpe genes was responsible for all the observed phenotypes. We also demonstrated the involvement of the vpe locus in gut colonization in the streptomycin-treated mouse model of intestinal colonization. These findings confirm that carbohydrate transport and metabolism underlie the ability of UPEC strains to colonize the host intestine and to infect various host sites.
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Fevre C, Passet V, Deletoile A, Barbe V, Frangeul L, Almeida AS, Sansonetti P, Tournebize R, Brisse S. PCR-based identification of Klebsiella pneumoniae subsp. rhinoscleromatis, the agent of rhinoscleroma. PLoS Negl Trop Dis 2011; 5:e1052. [PMID: 21629720 PMCID: PMC3101168 DOI: 10.1371/journal.pntd.0001052] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 04/26/2011] [Indexed: 11/21/2022] Open
Abstract
Rhinoscleroma is a chronic granulomatous infection of the upper airways caused by the bacterium Klebsiella pneumoniae subsp. rhinoscleromatis. The disease is endemic in tropical and subtropical areas, but its diagnosis remains difficult. As a consequence, and despite available antibiotherapy, some patients evolve advanced stages that can lead to disfiguration, severe respiratory impairment and death by anoxia. Because identification of the etiologic agent is crucial for the definitive diagnosis of the disease, the aim of this study was to develop two simple PCR assays. We took advantage of the fact that all Klebsiella pneumoniae subsp. rhinoscleromatis isolates are (i) of capsular serotype K3; and (ii) belong to a single clone with diagnostic single nucleotide polymorphisms (SNP). The complete sequence of the genomic region comprising the capsular polysaccharide synthesis (cps) gene cluster was determined. Putative functions of the 21 genes identified were consistent with the structure of the K3 antigen. The K3-specific sequence of gene Kr11509 (wzy) was exploited to set up a PCR test, which was positive for 40 K3 strains but negative when assayed on the 76 other Klebsiella capsular types. Further, to discriminate Klebsiella pneumoniae subsp. rhinoscleromatis from other K3 Klebsiella strains, a specific PCR assay was developed based on diagnostic SNPs in the phosphate porin gene phoE. This work provides rapid and simple molecular tools to confirm the diagnostic of rhinoscleroma, which should improve patient care as well as knowledge on the prevalence and epidemiology of rhinoscleroma.
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Affiliation(s)
- Cindy Fevre
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | - Virginie Passet
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | - Alexis Deletoile
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | | | - Lionel Frangeul
- Institut Pasteur, Intégration et Analyse Génomique, Paris, France
| | - Ana S. Almeida
- Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, Paris, France
- Unité INSERM U786, Institut Pasteur, Paris, France
| | - Philippe Sansonetti
- Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, Paris, France
- Unité INSERM U786, Institut Pasteur, Paris, France
| | - Régis Tournebize
- Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, Paris, France
- Unité INSERM U786, Institut Pasteur, Paris, France
| | - Sylvain Brisse
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
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Bushell SR, Lou H, Wallat GD, Beis K, Whitfield C, Naismith JH. Crystallization and preliminary diffraction analysis of Wzi, a member of the capsule export and assembly pathway in Escherichia coli. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1621-5. [PMID: 21139210 PMCID: PMC2998369 DOI: 10.1107/s1744309110040546] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 10/09/2010] [Indexed: 11/12/2022]
Abstract
External polysaccharide capsules provide a physical barrier that is employed by many species of bacteria for the purposes of host evasion and persistence. Wzi is a 53 kDa outer membrane β-barrel protein that is thought to play a role in the attachment of group 1 capsular polysaccharides to the cell surface. The purification and crystallization of an Escherichia coli homologue of Wzi is reported and diffraction data from native and selenomethionine-incorporated protein crystals are presented. Crystals of C-terminally His6-tagged Wzi diffracted to 2.8 Å resolution. Data processing showed that the crystals belonged to the orthorhombic space group C222, with unit-cell parameters a=128.8, b=152.8, c=94.4 Å, α=β=γ=90°. A His-tagged selenomethionine-containing variant of Wzi has also been crystallized in the same space group and diffraction data have been recorded to 3.8 Å resolution. Data processing shows that the variant crystal has similar unit-cell parameters to the native crystal.
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Affiliation(s)
- Simon R. Bushell
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Hubing Lou
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Gregor D. Wallat
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Konstantinos Beis
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Chris Whitfield
- Department of Molecular and Cell Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - James H. Naismith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
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46
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Clarke DJ. The Rcs phosphorelay: more than just a two-component pathway. Future Microbiol 2010; 5:1173-84. [DOI: 10.2217/fmb.10.83] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Rcs phosphorelay is a complex signaling pathway found in many, but not all, members of the Enterobacteriaceae. The complexity of this pathway is due to the direct involvement of three proteins (RcsC, RcsD and RcsB) in the phosphorelay and the presence of multiple accessory proteins with important roles in modulating the inputs and outputs associated with this signaling pathway. This article will discuss the various inputs and outputs associated with the Rcs phosphorelay and also present a model suggesting an important role for this signaling pathway in the temporal control of virulence in Salmonella enterica and biofilm formation in Escherichia coli.
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Affiliation(s)
- David J Clarke
- Department of Microbiology & Alimentary Pharmabiotic Centre, University College Cork, Ireland
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48
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Matsuda K, Chaudhari AA, Kim SW, Lee KM, Lee JH. Physiology, pathogenicity and immunogenicity of lon and/or cpxR deleted mutants of Salmonella Gallinarum as vaccine candidates for fowl typhoid. Vet Res 2010; 41:59. [PMID: 20487719 PMCID: PMC2887653 DOI: 10.1051/vetres/2010031] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 05/20/2010] [Indexed: 11/25/2022] Open
Abstract
To construct a novel live vaccine candidate for fowl typhoid (FT) caused by Salmonella Gallinarum (SG), the lon and cpxR genes that are related to host-pathogen interaction were deleted from a wild type SG using the allelic exchange method. The mutants were grown normally, as was the wild type. The biochemical properties of the mutants remained very similar to those of the wild-type, while JOL914 (Δlon) and JOL916 (ΔlonΔcpxR) were mucoid. Extracellular polysaccharide increased 30.6-, 1.3-, and 46.2-fold in JOL914, JOL915 (ΔcpxR), and JOL916, respectively. Dot-blot analysis demonstrated significant increases of FimA expression at 6.77-, 2.33-, and 3.90-fold for JOL914, JOL915, and JOL916, respectively. Internalizations of JOL914, JOL915, and JOL916, in chicken abdominal macrophages, were increased at 4.65-, 0.50-, and 2.72-fold, respectively. Virulences of JOL914, JOL915 and JOL916, analyzed by LD50 using 1-week-old chickens, were attenuated approximately at 101-, 101-, and > 103-fold, respectively. The oral inoculations of 2 × 107 cfu of the wild type, JOL914, JOL915 and JOL916 caused 55.6, 16.7, 22.2, and 0.0% mortality, respectively. Significantly moderate gross lesions of the liver and spleen were observed in the JOL916 group compared to the other groups. An induced immune response and significant peripheral mononuclear proliferation reaction were observed in the JOL916 group. At the protection against the wild type challenge, JOL916 offered 100% protection. Thus, the results of this study suggest that JOL916 among the mutants studied represented the safest and most effective live vaccine candidate against FT.
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Affiliation(s)
- Kiku Matsuda
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Jeonju, 561-756, Republic of Korea
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Shu HY, Fung CP, Liu YM, Wu KM, Chen YT, Li LH, Liu TT, Kirby R, Tsai SF. Genetic diversity of capsular polysaccharide biosynthesis in Klebsiella pneumoniae clinical isolates. MICROBIOLOGY-SGM 2009; 155:4170-4183. [PMID: 19744990 DOI: 10.1099/mic.0.029017-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Klebsiella pneumoniae is an enteric pathogen causing community-acquired and hospital-acquired infections in humans. Epidemiological studies have revealed significant diversity in capsular polysaccharide (CPS) type and clinical manifestation of K. pneumoniae infection in different geographical areas of the world. We have sequenced the capsular polysaccharide synthesis (cps) region of seven clinical isolates and compared the sequences with the publicly available cps sequence data of five strains: NTUH-K2044 (K1 serotype), Chedid (K2 serotype), MGH78578 (K52 serotype), A1142 (K57 serotype) and A1517. Among all strains, six genes at the 5' end of the cps clusters that encode proteins for CPS transportation and processing at the bacterial surface are highly similar to each other. The central region of the cps gene clusters, which encodes proteins for polymerization and assembly of the CPS subunits, is highly divergent. Based on the collected sequence, we found that either the wbaP gene or the wcaJ gene exists in a given K. pneumoniae strain, suggesting that there is a major difference in the CPS biosynthesis pathway and that the K. pneumoniae strains can be classified into at least two distinct groups. All isolates contain gnd, encoding gluconate-6-phosphate dehydrogenase, at the 3' end of the cps gene clusters. The rmlBADC genes were found in CPS K9-positive, K14-positive and K52-positive strains, while manC and manB were found in K1, K2, K5, K14, K62 and two undefined strains. Our data indicate that, while overall genomic organization is similar between different pathogenic K. pneumoniae strains, the genetic variation of the sugar moiety and polysaccharide linkage generate the diversity in CPS molecules that could help evade host immune attack.
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Affiliation(s)
- Hung-Yu Shu
- Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC.,Department of Bioscience Technology, Chang Jung Christian University, Tainan County, Taiwan, ROC
| | - Chang-Phone Fung
- Institute of Tropical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yen-Ming Liu
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Keh-Ming Wu
- Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Ying-Tsong Chen
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Ling-Hui Li
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Tze-Tze Liu
- Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Ralph Kirby
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Shih-Feng Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC.,Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC.,Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC
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Pereira S, Zille A, Micheletti E, Moradas-Ferreira P, De Philippis R, Tamagnini P. Complexity of cyanobacterial exopolysaccharides: composition, structures, inducing factors and putative genes involved in their biosynthesis and assembly. FEMS Microbiol Rev 2009; 33:917-41. [DOI: 10.1111/j.1574-6976.2009.00183.x] [Citation(s) in RCA: 439] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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