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Mettu R, Lih YH, Vulupala HR, Chen CY, Hsu MH, Lo HJ, Liao KS, Cheng YY, Chiu CH, Wu CY. Synthetic Library of Oligosaccharides Derived from the Capsular Polysaccharide of Streptococcus pneumoniae Serotypes 6A and 6B and Their Immunological Studies. ACS Infect Dis 2022; 8:626-634. [PMID: 35171577 DOI: 10.1021/acsinfecdis.1c00646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus pneumoniae serotypes 6A and 6B are two of the common causes of invasive pneumococcal diseases. Although capsular polysaccharide conjugates of these two serotypes are included in the leading 13-valent pneumococcal conjugate vaccine, its low immunogenicity and high threshold for manufacturing technology indicated the need for vaccine improvement. Structurally defined synthetic immunogens have potential in dealing with these problems. To this end, we built a library of capsular polysaccharide fragments through convergent chemical synthesis in [2 + 2], [4 + 4], [4 + 3], [4 + 2], and [4 + 1] coupling manners. The library is comprised of 18 glycan antigens from trisaccharides to pseudo-octasaccharides, derived from the capsular repeating phosphorylated pseudo-tetrasaccharide with or without phosphate. Eight of them were selected for mouse immunization and further immunological studies. Four pseudo-tetrasaccharides with terminal or bridging phosphate elicited opsonic antibodies, which exhibited bactericidal activities and moderate cross-reactivities.
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Affiliation(s)
- Ravinder Mettu
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Yu-Hsuan Lih
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, 128 Academia Road, Section 2,
Nankang, Taipei 11529, Taiwan
- Department of Chemistry, National Taiwan University, 1 Roosevelt Road, Section 4, Daan, Taipei 10617, Taiwan
| | - Hanmanth Reddy Vulupala
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Chiang-Yun Chen
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Mei-Hua Hsu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 259 Wenhua first Road, Guishan, Taoyuan 33302, Taiwan
| | - Hong-Jay Lo
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Kuo-Shiang Liao
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Yang-Yu Cheng
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Cheng-Hsun Chiu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 259 Wenhua first Road, Guishan, Taoyuan 33302, Taiwan
| | - Chung-Yi Wu
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, 128 Academia Road, Section 2,
Nankang, Taipei 11529, Taiwan
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2
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Zhou M, Wang Z, Zhang L, Kudinha T, An H, Qian C, Jiang B, Wang Y, Xu Y, Liu Z, Zhang H, Zhang J. Serotype Distribution, Antimicrobial Susceptibility, Multilocus Sequencing Type and Virulence of Invasive Streptococcus pneumoniae in China: A Six-Year Multicenter Study. Front Microbiol 2022; 12:798750. [PMID: 35095809 PMCID: PMC8793633 DOI: 10.3389/fmicb.2021.798750] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/08/2021] [Indexed: 11/13/2022] Open
Abstract
Background:Streptococcus pneumoniae is an important human pathogen that can cause severe invasive pneumococcal diseases (IPDs). The aim of this multicenter study was to investigate the serotype and sequence type (ST) distribution, antimicrobial susceptibility, and virulence of S. pneumoniae strains causing IPD in China. Methods: A total of 300 invasive S. pneumoniae isolates were included in this study. The serotype, ST, and antimicrobial susceptibility of the strains, were determined by the Quellung reaction, multi-locus sequence typing (MLST) and broth microdilution method, respectively. The virulence level of the strains in the most prevalent serotypes was evaluated by a mouse sepsis model, and the expression level of well-known virulence genes was measured by RT-PCR. Results: The most common serotypes in this study were 23F, 19A, 19F, 3, and 14. The serotype coverages of PCV7, PCV10, PCV13, and PPV23 vaccines on the strain collection were 42.3, 45.3, 73.3 and 79.3%, respectively. The most common STs were ST320, ST81, ST271, ST876, and ST3173. All strains were susceptible to ertapenem, levofloxacin, moxifloxacin, linezolid, and vancomycin, but a very high proportion (>95%) was resistant to macrolides and clindamycin. Based on the oral, meningitis and non-meningitis breakpoints, penicillin non-susceptible Streptococcus pneumoniae (PNSP) accounted for 67.7, 67.7 and 4.3% of the isolates, respectively. Serotype 3 strains were characterized by high virulence levels and low antimicrobial-resistance rates, while strains of serotypes 23F, 19F, 19A, and 14, exhibited low virulence and high resistance rates to antibiotics. Capsular polysaccharide and non-capsular virulence factors were collectively responsible for the virulence diversity of S. pneumoniae strains. Conclusion: Our study provides a comprehensive insight into the epidemiology and virulence diversity of S. pneumoniae strains causing IPD in China.
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Affiliation(s)
- Menglan Zhou
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Ziran Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Li Zhang
- Department of Infectious Disease, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Timothy Kudinha
- School of Biomedical Sciences, Charles Sturt University, Orange, NSW, Australia
- NSW Health Pathology, Regional and Rural, Orange Hospital, Orange, NSW, Australia
| | - Haoran An
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Chenyun Qian
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Bin Jiang
- Department of Clinical Laboratory, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, China
| | - Yao Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Yingchun Xu
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Zhengyin Liu
- Department of Infectious Disease, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- *Correspondence: Zhengyin Liu,
| | - Hong Zhang
- Department of Clinical Laboratory, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
- Hong Zhang,
| | - Jingren Zhang
- NSW Health Pathology, Regional and Rural, Orange Hospital, Orange, NSW, Australia
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
- Jingren Zhang,
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3
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Chaudhury A, Mukherjee MM, Ghosh R. Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A. Beilstein J Org Chem 2018; 14:1095-1102. [PMID: 29977381 PMCID: PMC6009338 DOI: 10.3762/bjoc.14.95] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/26/2018] [Indexed: 11/23/2022] Open
Abstract
Streptococcus pneumonia (SPn) is a Gram-positive bacterium which causes life threatening diseases. The bacteria protect themselves against non-specific host defence by an external polysaccharide (PS) capsule which bears a repeating unit, α-D-Galp(1->3)-α-D-Glcp(1->3)-α-L-Rhap(1->3)-D-Rib (SPn 6A). A closer look at the structure reveals the presence of α-linked galactose and glucose residues. The synthesis of these 1,2-cis glycosidic linkages are considered challenging particularly in the context of a one-pot oligosaccharide synthesis. We have synthesized the aforesaid tetrasaccharide (SPn 6A) based on both stepwise and sequential one-pot glycosylation reactions using easily accessible common building blocks; eventually similar overall yields were obtained in both cases.
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Affiliation(s)
- Aritra Chaudhury
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Rd., Kolkata 700032, India.,Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur, 741246, West Bengal, India
| | - Mana Mohan Mukherjee
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Rd., Kolkata 700032, India.,present addrress: Laboratory of Bioorganic Chemistry, NIH, NIDDK, Bethesda, MD, USA
| | - Rina Ghosh
- Department of Chemistry, Jadavpur University, 188, Raja S. C. Mullick Rd., Kolkata 700032, India
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4
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Streptococcus pneumoniae serogroup 6 clones over two decades. Epidemiol Infect 2014; 142:2501-13. [PMID: 24641988 DOI: 10.1017/s0950268814000508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The major evolutionary stresses on Streptococcus pneumoniae are thought to be the widespread use of antibiotics and the deployment of effective vaccines against the capsular polysaccharides. Our current knowledge of genetic lineages among pneumococcal isolates comes largely from investigations just before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) introduced in 2000. We examined 66 serogroup 6 isolates from the 1970s, long before the introduction of PCV7 and before widespread penicillin resistance was common in Birmingham, Alabama, to look for ancestors of the clones that came into play around the introduction of the PCV7 vaccine. The hypothesis was that some clonal complexes, if not individual clones, would be stable enough to persist over this period of time. We compared the 1970s isolates with 122 isolates from the 1990s in US and worldwide collections. Genotyping with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) revealed that while some clones were probably localized to our area, others have persisted within groups that have expanded or diminished over the years.
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5
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Bonofiglio L, Regueira M, Pace J, Corso A, García E, Mollerach M. Dissemination of an Erythromycin-Resistant Penicillin-NonsusceptibleStreptococcus pneumoniaePoland6B-20 Clone in Argentina. Microb Drug Resist 2011; 17:75-81. [DOI: 10.1089/mdr.2010.0027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Laura Bonofiglio
- Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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6
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Bratcher PE, Park IH, Oliver MB, Hortal M, Camilli R, Hollingshead SK, Camou T, Nahm MH. Evolution of the capsular gene locus of Streptococcus pneumoniae serogroup 6. MICROBIOLOGY-SGM 2010; 157:189-198. [PMID: 20929956 PMCID: PMC3068628 DOI: 10.1099/mic.0.043901-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Streptococcus pneumoniae expressing serogroup 6 capsules frequently causes pneumococcal infections and the evolutionary origins of the serogroup 6 strains have been extensively studied. However, these studies were performed when serogroup 6 had only two known members (serotypes 6A and 6B) and before the two new members (serotypes 6C and 6D) expressing wciNβ were found. We have therefore reinvestigated the evolutionary origins of serogroup 6 by examining the profiles of the capsule gene loci and the multilocus sequence types (MLSTs) of many serogroup 6 isolates from several continents. We confirmed that there are two classes of cps locus sequences for serogroup 6 isolates. In our study, class 2 cps sequences were limited to a few serotype 6B isolates. Neighbour-joining analysis of cps sequence profiles showed a distinct clade for 6C and moderately distinct clades for class 1 6A and 6B sequences. The serotype 6D cps profile was found within the class 1 6B clade, suggesting that it was created by recombination between 6C and 6B cps loci. Interestingly, all 6C isolates also had a unique wzy allele with a 6 bp deletion. This suggests that serotype switching to 6C involves the transfer of a large (>4 kb) gene segment that includes both the wciNβ allele and the ‘short’ wzy allele. The MLST studies of serotype 6C isolates suggest that the 6C cps locus is incorporated into many different pneumococcal genomic backgrounds but that, interestingly, 6C cps may have preferentially entered strains of the same genomic backgrounds as those of serotype 6A.
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Affiliation(s)
- P E Bratcher
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - I H Park
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - M B Oliver
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - M Hortal
- Maternal and Child Health Department, Ministry of Public Health Montevideo, Uruguay
| | - R Camilli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - S K Hollingshead
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - T Camou
- Maternal and Child Health Department, Ministry of Public Health Montevideo, Uruguay
| | - M H Nahm
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.,Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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7
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Parameswar AR, Park IH, Saksena R, Kovác P, Nahm MH, Demchenko AV. Synthesis, conjugation, and immunological evaluation of the serogroup 6 pneumococcal oligosaccharides. Chembiochem 2010; 10:2893-9. [PMID: 19856369 DOI: 10.1002/cbic.200900587] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The first synthesis of the newly discovered oligosaccharide of pneumococcal serotype 6C and its spacer-containing analogue is reported. Conjugation of the spacer-containing oligosaccharides of pneumococcal saccharides 6A, 6B, 6C and derivatives thereof with bovine serum albumin (BSA) protein carrier was carried out by using squaric-acid approach to obtain the oligosaccharide-protein conjugates in excellent yields. The conjugates have been tested with a rabbit antiserum pool (Pool B) used for pneumococcal serotyping. The results showed that synthetic carbohydrate conjugates express epitopes found in native capsular polysaccharides of serotypes 6A, 6B, and 6C.
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Affiliation(s)
- Archana R Parameswar
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, 63121, USA
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8
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Bratcher PE, Park IH, Hollingshead SK, Nahm MH. Production of a unique pneumococcal capsule serotype belonging to serogroup 6. MICROBIOLOGY-SGM 2009; 155:576-583. [PMID: 19202106 DOI: 10.1099/mic.0.024521-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Serogroup 6 of Streptococcus pneumoniae contains three serotypes, named 6A, 6B and 6C, with highly homologous capsule gene loci. The 6A and 6B capsule gene loci consistently differ from each other by only one nucleotide in the wciP gene. The 6A capsule gene locus has a galactosyltransferase, which has been replaced with a glucosyltransferase in the 6C capsule gene locus. We considered that a new serotype named '6X1' would be possible if the galactosyltransferase of the 6B capsule gene locus is replaced with the glucosyltransferase of 6C. We demonstrate that this gene transfer yields a viable pneumococcal strain and that the capsular polysaccharide (PS) from this strain has the predicted chemical structure and serological similarity to the capsular PS of the 6B serotype. The new strain (i.e. serotype 6X1) is typed as 6B by the quellung reaction, but it can be distinguished from 6B strains with mAbs to 6B PS. Reexamination of 264 pneumococcal isolates that had been previously typed as 6B with classical typing methods revealed no isolates expressing serotype 6X1. Nevertheless, this study shows that this capsular PS is biochemically possible and could exist/emerge in nature.
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Affiliation(s)
- Preston E Bratcher
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - In H Park
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Susan K Hollingshead
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Moon H Nahm
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.,Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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9
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Parameswar AR, Hasty SJ, Demchenko AV. Synthesis of spacer-containing analogs of serogroup 6 pneumococcal oligosaccharides. Carbohydr Res 2008; 343:1707-17. [PMID: 18439990 DOI: 10.1016/j.carres.2008.03.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 03/23/2008] [Accepted: 03/30/2008] [Indexed: 12/18/2022]
Abstract
An efficient convergent strategy for the synthesis of a range of spacer-containing pneumococcal oligosaccharides of serogroup 6 and derivatives thereof has been developed. The spacer-containing oligosaccharides were deprotected and are available for subsequent conjugation and immunological studies, which are underway in our laboratory.
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Affiliation(s)
- Archana R Parameswar
- Department of Chemistry and Biochemistry, University of Missouri, St Louis, One University Boulevard, St Louis, MO 63121, USA
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10
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Parameswar AR, Pornsuriyasak P, Lubanowski NA, Demchenko AV. Efficient stereoselective synthesis of oligosaccharides of Streptococcus pneumoniae serotypes 6A and 6B containing multiple 1,2-cis glycosidic linkages. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.07.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Park IH, Park S, Hollingshead SK, Nahm MH. Genetic basis for the new pneumococcal serotype, 6C. Infect Immun 2007; 75:4482-9. [PMID: 17576753 PMCID: PMC1951153 DOI: 10.1128/iai.00510-07] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have recently reported a new pneumococcal serotype (6C), which is closely related to serotype 6A (I. H. Park et al., J. Clin. Microbiol. 45:1225-1233, 2007). To investigate the genetic basis for serotype 6C, we studied the capsule gene loci of 14 6C isolates from three different continents, including one isolated in Alabama 27 years ago. The wciN region of all 6C isolates has a 1,029-bp-long sequence that replaces the 1,222-bp-long sequence of the 6A wciN region. This recombination event has created a new 1,125-bp-long open reading frame which encodes a product that is also homologous to glycosyl transferases. Flanking this introduced gene is 300 bp upstream and 100 bp downstream with only about 90% homology with 6A and which is identical in all 6C isolates. Transfer of the wciN region converts 6A to 6C. Determination of the DNA sequence of the entire capsule gene locus of one 6C isolate showed that the 6C capsule gene locus is almost identical (>98% homologous) to that of 6A except for the wciN region. These findings indicate that the 6C capsule type originated more than 27 years ago by a single recombination event in a 6A locus in which 6A wciN was replaced by a gene of unknown origin.
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Affiliation(s)
- In Ho Park
- Department of Pathology, University of Alabama at Birmingham, 845 19th Street South, BBRB 614, Birmingham, AL 35294, USA
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12
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Shen K, Gladitz J, Antalis P, Dice B, Janto B, Keefe R, Hayes J, Ahmed A, Dopico R, Ehrlich N, Jocz J, Kropp L, Yu S, Nistico L, Greenberg DP, Barbadora K, Preston RA, Post JC, Ehrlich GD, Hu FZ. Characterization, distribution, and expression of novel genes among eight clinical isolates of Streptococcus pneumoniae. Infect Immun 2006; 74:321-30. [PMID: 16368987 PMCID: PMC1346598 DOI: 10.1128/iai.74.1.321-330.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eight low-passage-number Streptococcus pneumoniae clinical isolates, each of a different serotype and a different multilocus sequence type, were obtained from pediatric participants in a pneumococcal vaccine trial. Comparative genomic analyses were performed with these strains and two S. pneumoniae reference strains. Individual genomic libraries were constructed for each of the eight clinical isolates, with an average insert size of approximately 1 kb. A total of 73,728 clones were picked for arraying, providing more than four times genomic coverage per strain. A subset of 4,793 clones were sequenced, for which homology searches revealed that 750 (15.6%) of the sequences were unique with respect to the TIGR4 reference genome and 263 (5.5%) clones were unrelated to any available streptococcal sequence. Hypothetical translations of the open reading frames identified within these novel sequences showed homologies to a variety of proteins, including bacterial virulence factors not previously identified in S. pneumoniae. The distribution and expression patterns of 58 of these novel sequences among the eight clinical isolates were analyzed by PCR- and reverse transcriptase PCR-based analyses, respectively. These unique sequences were nonuniformly distributed among the eight isolates, and transcription of these genes in planktonic cultures was detected in 81% (172/212) of their genic occurrences. All 58 novel sequences were transcribed in one or more of the clinical strains, suggesting that they all correspond to functional genes. Sixty-five percent (38/58) of these sequences were found in 50% or less of the clinical strains, indicating a significant degree of genomic plasticity among natural isolates.
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Affiliation(s)
- Kai Shen
- Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, 320 East North Avenue, 11th Floor South Tower, Pittsburgh, PA 15212, USA
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13
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Willems RJL, Top J, van Santen M, Robinson DA, Coque TM, Baquero F, Grundmann H, Bonten MJM. Global spread of vancomycin-resistant Enterococcus faecium from distinct nosocomial genetic complex. Emerg Infect Dis 2005. [PMID: 15963275 PMCID: PMC3367597 DOI: 10.3201/eid1106.041204] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Vancomycin-resistant enterococci (VRE) have caused hospital outbreaks worldwide, and the vancomycin-resistance gene (vanA) has crossed genus boundaries to methicillin-resistant Staphylococcus aureus. Spread of VRE, therefore, represents an immediate threat for patient care and creates a reservoir of mobile resistance genes for other, more virulent pathogens. Evolutionary genetics, population structure, and geographic distribution of 411 VRE and vancomycin-susceptible Enterococcus faecium isolates, recovered from human and nonhuman sources and community and hospital reservoirs in 5 continents, identified a genetic lineage of E. faecium (complex-17) that has spread globally. This lineage is characterized by 1) ampicillin resistance, 2) a pathogenicity island, and 3) an association with hospital outbreaks. Complex-17 is an example of cumulative evolutionary processes that improved the relative fitness of bacteria in hospital environments. Preventing further spread of this epidemic E. faecium subpopulation is critical, and efforts should focus on the early disclosure of ampicillin-resistant complex-17 strains.
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Affiliation(s)
- Rob J L Willems
- University Medical Center Utrecht, Utrecht, the Netherlands.
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14
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Willems RJL, Top J, van Santen M, Robinson DA, Coque TM, Baquero F, Grundmann H, Bonten MJM. Global Spread of Vancomycin-resistantEnterococcus faeciumfrom Distinct Nosocomial Genetic Complex. Emerg Infect Dis 2005; 11:821-8. [PMID: 15963275 PMCID: PMC3367597 DOI: 10.3201/1106.041204] [Citation(s) in RCA: 385] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Vancomycin-resistant enterococci (VRE) have caused hospital outbreaks worldwide, and the vancomycin-resistance gene (vanA) has crossed genus boundaries to methicillin-resistant Staphylococcus aureus. Spread of VRE, therefore, represents an immediate threat for patient care and creates a reservoir of mobile resistance genes for other, more virulent pathogens. Evolutionary genetics, population structure, and geographic distribution of 411 VRE and vancomycin-susceptible Enterococcus faecium isolates, recovered from human and nonhuman sources and community and hospital reservoirs in 5 continents, identified a genetic lineage of E. faecium (complex-17) that has spread globally. This lineage is characterized by 1) ampicillin resistance, 2) a pathogenicity island, and 3) an association with hospital outbreaks. Complex-17 is an example of cumulative evolutionary processes that improved the relative fitness of bacteria in hospital environments. Preventing further spread of this epidemic E. faecium subpopulation is critical, and efforts should focus on the early disclosure of ampicillin-resistant complex-17 strains.
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Affiliation(s)
- Rob J L Willems
- University Medical Center Utrecht, Utrecht, the Netherlands.
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15
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McChlery SM, Scott KJ, Clarke SC. Clonal analysis of invasive pneumococcal isolates in Scotland and coverage of serotypes by the licensed conjugate polysaccharide pneumococcal vaccine: possible implications for UK vaccine policy. Eur J Clin Microbiol Infect Dis 2005; 24:262-7. [PMID: 15902532 DOI: 10.1007/s10096-005-1313-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A 7-valent pneumococcal conjugate vaccine (PCV7) has gained licensure and has proven successful in the USA for preventing pneumococcal disease and reducing the incidence of antibiotic-resistant pneumococcal strains. The ability, therefore, to accurately monitor the likely effect of the introduction of PCV7 vaccine on invasive pneumococcal disease in the UK is essential. Serotyping and multilocus sequence typing was performed on invasive isolates of Streptococcus pneumoniae (n=645) from Scotland during 2003. The information gained from this was used to evaluate serotype coverage by the vaccine and the relationship between serotypes. In the present study, invasive pneumococcal disease in Scotland was caused by 33 different serotypes, consisting of 150 sequence types. Overall, 48.4% of the isolates were of serotypes included in the PCV7. Pneumococci were most frequently associated with sequence types 9, 124, and 162. PCV7 would provide protection in 71.8% of infants under 5 years of age against the serotypes in the vaccine. There was limited evidence of the potential for capsule switch among currently circulating invasive pneumococci. The successful implementation of a suitable vaccination programme should lead to a reduction in invasive pneumococcal disease in the UK as well as a reduction in antibiotic resistance of pneumococcal strains.
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Affiliation(s)
- S M McChlery
- Scottish Meningococcus and Pneumococcus Reference Laboratory, Glasgow, UK
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Aurell H, Farge P, Meugnier H, Gouy M, Forey F, Lina G, Vandenesch F, Etienne J, Jarraud S. Clinical and environmental isolates of Legionella pneumophila serogroup 1 cannot be distinguished by sequence analysis of two surface protein genes and three housekeeping genes. Appl Environ Microbiol 2005; 71:282-9. [PMID: 15640199 PMCID: PMC544207 DOI: 10.1128/aem.71.1.282-289.2005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used gene sequencing to determine whether clinical (sporadic, epidemic, and endemic) and environmental isolates of Legionella pneumophila serogroup (sg) 1 belong to specific lineages. A total of 178 clinical and environmental L. pneumophila sg 1 isolates, defined by pulsed-field gel electrophoresis and epidemiological data as sporadic, epidemic, or endemic, were analyzed for polymorphisms in five gene fragments. The fragments belonged to three housekeeping genes (coding for aconitase [acn], aspartate-beta-semialdehyde dehydrogenase [asd], and RNA polymerase beta subunit [rpoB]) and two surface protein genes (coding for the macrophage infectivity potentiator [mip] and the major outer membrane protein [mompS]). The phylogenetic tree inferred from sequence polymorphisms of the five genes identified two large clusters, one consisting of 133 poorly differentiated strains and containing two smaller clusters (10 and 2 strains) unrelated to each other and the other consisting of 42 strains. Clinical and environmental isolates could not be distinguished on this basis, and no link between genetic background and epidemiological type was found, suggesting that other factors are responsible for differences in pathogenicity.
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Affiliation(s)
- Helena Aurell
- Centre National de Référence des Legionella, INSERM E-0230, Laboratoire de Bactériologie, Faculté de Médecine Laennec IFR 62, 7 rue Guillaume Paradin, 69372 Lyon cedex 08, France
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Mavroidi A, Godoy D, Aanensen DM, Robinson DA, Hollingshead SK, Spratt BG. Evolutionary genetics of the capsular locus of serogroup 6 pneumococci. J Bacteriol 2005; 186:8181-92. [PMID: 15576766 PMCID: PMC532438 DOI: 10.1128/jb.186.24.8181-8192.2004] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The evolution of the capsular biosynthetic (cps) locus of serogroup 6 Streptococcus pneumoniae was investigated by analyzing sequence variation within three serotype-specific cps genes from 102 serotype 6A and 6B isolates. Sequence variation within these cps genes was related to the genetic relatedness of the isolates, determined by multilocus sequence typing, and to the inferred patterns of recent evolutionary descent, explored using the eBURST algorithm. The serotype-specific cps genes had a low percent G+C, and there was a low level of sequence diversity in this region among serotype 6A and 6B isolates. There was also little sequence divergence between these serotypes, suggesting a single introduction of an ancestral cps sequence, followed by slight divergence to create serotypes 6A and 6B. A minority of serotype 6B isolates had cps sequences (class 2 sequences) that were approximately 5% divergent from those of other serotype 6B isolates (class 1 sequences) and which may have arisen by a second, more recent introduction from a related but distinct source. Expression of a serotype 6A or 6B capsule correlated perfectly with a single nonsynonymous polymorphism within wciP, the rhamnosyl transferase gene. In addition to ample evidence of the horizontal transfer of the serotype 6A and 6B cps locus into unrelated lineages, there was evidence for relatively frequent changes from serotype 6A to 6B, and vice versa, among very closely related isolates and examples of recent recombinational events between class 1 and 2 cps serogroup 6 sequences.
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Affiliation(s)
- Angeliki Mavroidi
- Department of Infectious Disease Epidemiology, Imperial College London, Room G22, Old Medical School Building, St. Mary's Hospital, Norfolk Place, London W2 1PG, United Kingdom
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Gherardi G, Del Grosso M, Scotto D'Abusco A, D'Ambrosio F, Dicuonzo G, Pantosti A. Phenotypic and genotypic characterization of two penicillin-susceptible serotype 6B Streptococcus pneumoniae clones circulating in Italy. J Clin Microbiol 2003; 41:2855-61. [PMID: 12843012 PMCID: PMC165367 DOI: 10.1128/jcm.41.7.2855-2861.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Twenty-nine penicillin-susceptible serotype 6B strains isolated from patients with invasive diseases and from healthy carriers were examined by different genotyping methods. Ten groups were identified on the basis of the pulsed-field gel electrophoresis (PFGE) profiles, and two of these contained multiple isolates and were analyzed further. PFGE group 1 comprised 12 isolates, the majority of which had a multiresistant phenotype (resistance to erythromycin, clindamycin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole), corresponding to that of a clone previously described in the Mediterranean area and related to penicillin-resistant clone Spain(6B)-2. The pbp2b, pbp2x, dhf, and pspA genes of the isolates had identical restriction profiles; and the partial sequence of pspA was identical to that of clone Spain(6B)-2. In all isolates the resistance determinants erm(B) and tet(M) were inserted in a Tn1545-like element; 11 isolates carried cat as part of the integrated plasmid pC194. Multilocus sequence typing (MLST) performed with two isolates confirmed that their profiles corresponded to that of the Mediterranean clone. PFGE group 2 comprised nine strains, of which the majority showed no antibiotic resistance. Their pspA profiles were different, and the partial sequences obtained for two representative isolates indicated the presence of PspA proteins of different clades. The MLST profile of one strain was identical to that of a serotype 6B strain from the United Kingdom, while two other isolates were novel one-allele variants. This clone appears to be related (five of seven identical alleles) to two other internationally disseminated clones, Hungary(19A)-6 and Poland(23F)-16, both of which are penicillin resistant. The presence of antibiotic-susceptible isolates of this clone suggests that traits other than antibiotic resistance can make a clone successful.
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Affiliation(s)
- Giovanni Gherardi
- Dipartimento di Medicina di Laboratorio e Microbiologia, Università Campus Biomedico, Rome, Italy
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Yother J, Trieu-Cuot P, Klaenhammer TR, De Vos WM. Genetics of streptococci, lactococci, and enterococci: review of the sixth international conference. J Bacteriol 2002; 184:6085-92. [PMID: 12399476 PMCID: PMC151966 DOI: 10.1128/jb.184.22.6085-6092.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Janet Yother
- Department of Microbiology, University of Alabama at Birmingham, 35294, USA.
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