1
|
Sun J, Wen S, Wang Z, Liu W, Lin Y, Gu J, Mao W, Xu X, He Q, Cai X. Glaesserella parasuis QseBC two-component system senses epinephrine and regulates capD expression. Microbiol Spectr 2023; 11:e0150823. [PMID: 37882555 PMCID: PMC10714720 DOI: 10.1128/spectrum.01508-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/16/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The key bacterial pathogen Glaesserella parasuis, which can cause Glässer's disease, has caused significant financial losses to the swine industry worldwide. Capsular polysaccharide (CPS) is an important virulence factor for bacteria, providing the ability to avoid recognition and killing by the host immune system. Exploring the alteration of CPS synthesis in G. parasuis in response to epinephrine stimulation can lay the groundwork for revealing the pathogenic mechanism of G. parasuis as well as providing ideas for Glässer's disease control.
Collapse
Affiliation(s)
- Ju Sun
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Siting Wen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Zhichao Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wei Liu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yan Lin
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jiayun Gu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Weiting Mao
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaojuan Xu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Qigai He
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xuwang Cai
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, China
| |
Collapse
|
2
|
Shen Y, Shi Z, Zhao J, Li M, Tang J, Wang N, Mo Y, Yang T, Zhou X, Chen Q, Yang P. Whole genome sequencing provides evidence for Bacillus velezensis SH-1471 as a beneficial rhizosphere bacterium in plants. Sci Rep 2023; 13:20929. [PMID: 38017088 PMCID: PMC10684890 DOI: 10.1038/s41598-023-48171-9] [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: 07/10/2023] [Accepted: 11/23/2023] [Indexed: 11/30/2023] Open
Abstract
Bacillus is widely used in agriculture due to its diverse biological activities. We isolated a Bacillus velezensis SH-1471 from the rhizosphere soil of healthy tobacco, which has broad-spectrum antagonistic activity against a variety of plant pathogenic fungi such as Fusarium oxysporum, and can be colonized in the rhizosphere of a variety of plants. This study will further explore its mechanism by combining biological and molecular biology methods. SH-1471 contains a ring chromosome of 4,181,346 bp with a mean G + C content of 46.18%. We identified 14 homologous genes related to biosynthesis of resistant secondary metabolite, and three clusters encoded potential new antibacterial substances. It also contains a large number of genes from colonizing bacteria and genes related to plant bacterial interactions. It also contains genes related to environmental stress, as well as genes related to drug resistance. We also found that there are many metabolites in the strain that can inhibit the growth of pathogens. In addition, our indoor pot test found that SH-1471 has a good control effect on tomato wilt, and could significantly improve plant height, stem circumference, root length, root weight, and fresh weight and dry weight of the aboveground part of tomato seedlings. Therefore, SH-1471 is a potential biological control strain with important application value. The results of this study will help to further study the mechanism of SH-1471 in biological control of plant diseases and promote its application.
Collapse
Affiliation(s)
- Yunxin Shen
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, 655508, China
| | - Zhufeng Shi
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
| | - Jiangyuan Zhao
- Yunnan Institute of Microbiology, Yunnan University, Kunming, 650106, China
| | - Minggang Li
- Yunnan Institute of Microbiology, Yunnan University, Kunming, 650106, China
| | - Jiacai Tang
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
| | - Nan Wang
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, 655508, China
| | - Yanfang Mo
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, 655508, China
| | - Tongyu Yang
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, 655508, China
| | - Xudong Zhou
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China
| | - Qibin Chen
- College of Plant Protection, Yunnan Agricultural University, Kunming, 655508, China.
| | - Peiweng Yang
- Institute of Agricultural Environment and Resources, Yunnan Academy of Agricultural Sciences, Kunming, 650204, China.
| |
Collapse
|
3
|
Patel H, Rawat S. A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis. Front Microbiol 2023; 14:1204428. [PMID: 37434702 PMCID: PMC10332168 DOI: 10.3389/fmicb.2023.1204428] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/30/2023] [Indexed: 07/13/2023] Open
Abstract
Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.
Collapse
Affiliation(s)
| | - Seema Rawat
- Microbiology Laboratory, School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India
| |
Collapse
|
4
|
Tien N, Ho CY, Lai SJ, Lin YC, Yang CS, Wang YC, Huang WC, Chen Y, Chang JJ. Crystal structure of the capsular polysaccharide-synthesis enzyme CapG from Staphylococcus aureus. Acta Crystallogr F Struct Biol Commun 2022; 78:378-385. [PMID: 36322423 PMCID: PMC9629516 DOI: 10.1107/s2053230x22008743] [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: 06/29/2022] [Accepted: 08/31/2022] [Indexed: 11/05/2022] Open
Abstract
Bacterial capsular polysaccharides provide protection against environmental stress and immune evasion from the host immune system, and are therefore considered to be attractive therapeutic targets for the development of anti-infectious reagents. Here, we focused on CapG, one of the key enzymes in the synthesis pathway of capsular polysaccharides type 5 (CP5) from the opportunistic pathogen Staphylococcus aureus. SaCapG catalyses the 2-epimerization of UDP-N-acetyl-D-talosamine (UDP-TalNAc) to UDP-N-acetyl-D-fucosamine (UDP-FucNAc), which is one of the nucleotide-activated precursors for the synthesis of the trisaccharide repeating units of CP5. Here, the cloning, expression and purification of recombinant SaCapG are reported. After extensive efforts, single crystals of SaCapG were successfully obtained which belonged to space group C2 and exhibited unit-cell parameters a = 302.91, b = 84.34, c = 145.09 Å, β = 110.65°. The structure was solved by molecular replacement and was refined to 3.2 Å resolution. The asymmetric unit revealed a homohexameric assembly of SaCapG, which was consistent with gel-filtration analysis. Structural comparison with UDP-N-acetyl-D-glucosamine 2-epimerase from Methanocaldococcus jannaschii identified α2, the α2-α3 loop and α10 as a gate-regulated switch controlling substrate entry and/or product release.
Collapse
Affiliation(s)
- Ni Tien
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Chien-Yi Ho
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
- Division of Family Medicine, China Medical University Hsinchu Hospital, Hsinchu, Taiwan
- Physical Examination Center, China Medical University Hsinchu Hospital, Hsinchu, Taiwan
- Department of Medical Research, China Medical University Hsinchu Hospital, Hsinchu, Taiwan
| | - Shu-Jung Lai
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
- Research Center for Cancer Biology, China Medical University, Taichung, Taiwan
| | - Yu-Chuan Lin
- Translational Cell Therapy Center, China Medical University Hospital, Taichung, Taiwan
| | - Chia-Shin Yang
- Institute of Translational Medicine and New Drug Development, China Medical University, Taichung, Taiwan
| | - Yu-Chuan Wang
- Institute of Translational Medicine and New Drug Development, China Medical University, Taichung, Taiwan
| | - Wei-Chien Huang
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
- Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan
- Drug Development Center, China Medical University, Taichung, Taiwan
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan
| | - Yeh Chen
- Institute of Translational Medicine and New Drug Development, China Medical University, Taichung, Taiwan
| | - Jui-Jen Chang
- Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
| |
Collapse
|
5
|
Glycoconjugate pathway connections revealed by sequence similarity network analysis of the monotopic phosphoglycosyl transferases. Proc Natl Acad Sci U S A 2021; 118:2018289118. [PMID: 33472976 DOI: 10.1073/pnas.2018289118] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The monotopic phosphoglycosyl transferase (monoPGT) superfamily comprises over 38,000 nonredundant sequences represented in bacterial and archaeal domains of life. Members of the superfamily catalyze the first membrane-committed step in en bloc oligosaccharide biosynthetic pathways, transferring a phosphosugar from a soluble nucleoside diphosphosugar to a membrane-resident polyprenol phosphate. The singularity of the monoPGT fold and its employment in the pivotal first membrane-committed step allows confident assignment of both protein and corresponding pathway. The diversity of the family is revealed by the generation and analysis of a sequence similarity network for the superfamily, with fusion of monoPGTs with other pathway members being the most frequent and extensive elaboration. Three common fusions were identified: sugar-modifying enzymes, glycosyl transferases, and regulatory domains. Additionally, unexpected fusions of the monoPGT with members of the polytopic PGT superfamily were discovered, implying a possible evolutionary link through the shared polyprenol phosphate substrate. Notably, a phylogenetic reconstruction of the monoPGT superfamily shows a radial burst of functionalization, with a minority of members comprising only the minimal PGT catalytic domain. The commonality and identity of the fusion partners in the monoPGT superfamily is consistent with advantageous colocalization of pathway members at membrane interfaces.
Collapse
|
6
|
Chakraborty T, Polley S, Sinha D, Seal S, Sinha D, Mitra SK, Hazra J, Sau K, Pal M, Sau S. Structurally distinct unfolding intermediates formed from a staphylococcal capsule-producing enzyme retained NADPH binding activity. J Biomol Struct Dyn 2021; 40:9126-9143. [PMID: 33977860 DOI: 10.1080/07391102.2021.1924269] [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: 12/14/2022]
Abstract
CapF, a capsule-producing enzyme expressed by Staphylococcus aureus, binds NADPH and exists as a dimer in the aqueous solution. Many other capsule-producing virulent bacteria also express CapF orthologs. To understand the folding-unfolding mechanism of S. aureus CapF, herein a recombinant CapF (rCapF) was individually investigated using urea and guanidine hydrochloride (GdnCl). Unfolding of rCapF by both the denaturants was reversible but proceeded via the synthesis of a different number of intermediates. While two dimeric intermediates (rCapF4 and rCapF5) were formed at 0.5 M and 1.5 M GdnCl, three dimeric intermediates (rCapF1, rCapF2, and rCapF3) were produced at 1 M, 2 M, and 3 M urea, respectively. rCapF5 showed 3.6 fold less NADPH binding activity, whereas other intermediates retained full NADPH binding activity. Compared to rCapF, all of the intermediates (except rCapF3) had a compressed shape. Conversely, rCapF3 possessed a native protein-like shape. The maximum shape loss was in rCapF4 though its secondary structure remained unperturbed. Additionally, the tertiary structure and hydrophobic surface area of the intermediates neither matched with each other nor with those of the native rCapF. Of the four Trp residues in rCapF, one or more Trp residues in the intermediates may have higher solvent accessibility. Using sequence alignment and a tertiary structural model of CapF, we have demonstrated that the region around Trp 137 of CapF may be most sensitive to unfolding, whereas the NADPH binding motif carrying region at the N-terminal end of this protein may be resistant to unfolding, particularly at the low denaturant concentrations.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
| | - Soumitra Polley
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Debabrata Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Soham Seal
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Debasmita Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Sudip K Mitra
- Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India
| | - Joyita Hazra
- Division of Molecular Medicine, Bose Institute, Kolkata, West Bengal, India
| | - Keya Sau
- Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India
| | - Mahadeb Pal
- Division of Molecular Medicine, Bose Institute, Kolkata, West Bengal, India
| | - Subrata Sau
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| |
Collapse
|
7
|
Immune System Evasion Mechanisms in Staphylococcus aureus: Current Understanding. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.4.01] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen that may cause a wide range of infections and is a frequent cause of soft tissue and bloodstream infections. It is a successful pathogen due to its collective virulence factors and its ability to evade the host immune systems. The review aims to highlight how S. aureus destroys and damage the host cells and explains how immune cells can respond to this pathogen. This review may also provide new insights that may be useful for developing new strategy for combating MRSA and its emerging clones such as community-associated methicillin-resistant S. aureus (CA-MRSA).
Collapse
|
8
|
Discovery of an antivirulence compound that reverses β-lactam resistance in MRSA. Nat Chem Biol 2019; 16:143-149. [PMID: 31768032 DOI: 10.1038/s41589-019-0401-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 09/17/2019] [Accepted: 10/07/2019] [Indexed: 02/06/2023]
Abstract
Staphylococcus aureus is the leading cause of infections worldwide, and methicillin-resistant strains (MRSA) are emerging. New strategies are urgently needed to overcome this threat. Using a cell-based screen of ~45,000 diverse synthetic compounds, we discovered a potent bioactive, MAC-545496, that reverses β-lactam resistance in the community-acquired MRSA USA300 strain. MAC-545496 could also serve as an antivirulence agent alone; it attenuates MRSA virulence in Galleria mellonella larvae. MAC-545496 inhibits biofilm formation and abrogates intracellular survival in macrophages. Mechanistic characterization revealed MAC-545496 to be a nanomolar inhibitor of GraR, a regulator that responds to cell-envelope stress and is an important virulence factor and determinant of antibiotic resistance. The small molecule discovered herein is an inhibitor of GraR function. MAC-545496 has value as a research tool to probe the GraXRS regulatory system and as an antibacterial lead series of a mechanism to combat drug-resistant Staphylococcal infections.
Collapse
|
9
|
Coordination of capsule assembly and cell wall biosynthesis in Staphylococcus aureus. Nat Commun 2019; 10:1404. [PMID: 30926919 PMCID: PMC6441080 DOI: 10.1038/s41467-019-09356-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 02/28/2019] [Indexed: 11/08/2022] Open
Abstract
The Gram-positive cell wall consists of peptidoglycan functionalized with anionic glycopolymers, such as wall teichoic acid and capsular polysaccharide (CP). How the different cell wall polymers are assembled in a coordinated fashion is not fully understood. Here, we reconstitute Staphylococcus aureus CP biosynthesis and elucidate its interplay with the cell wall biosynthetic machinery. We show that the CapAB tyrosine kinase complex controls multiple enzymatic checkpoints through reversible phosphorylation to modulate the consumption of essential precursors that are also used in peptidoglycan biosynthesis. In addition, the CapA1 activator protein interacts with and cleaves lipid-linked CP precursors, releasing the essential lipid carrier undecaprenyl-phosphate. We further provide biochemical evidence that the subsequent attachment of CP is achieved by LcpC, a member of the LytR-CpsA-Psr protein family, using the peptidoglycan precursor native lipid II as acceptor substrate. The Ser/Thr kinase PknB, which can sense cellular lipid II levels, negatively controls CP synthesis. Our work sheds light on the integration of CP biosynthesis into the multi-component Gram-positive cell wall.
Collapse
|
10
|
Mohamed N, Timofeyeva Y, Jamrozy D, Rojas E, Hao L, Silmon de Monerri NC, Hawkins J, Singh G, Cai B, Liberator P, Sebastian S, Donald RGK, Scully IL, Jones CH, Creech CB, Thomsen I, Parkhill J, Peacock SJ, Jansen KU, Holden MTG, Anderson AS. Molecular epidemiology and expression of capsular polysaccharides in Staphylococcus aureus clinical isolates in the United States. PLoS One 2019; 14:e0208356. [PMID: 30641545 PMCID: PMC6331205 DOI: 10.1371/journal.pone.0208356] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
Staphylococcus aureus capsular polysaccharides (CP) are important virulence factors under evaluation as vaccine antigens. Clinical S. aureus isolates have the biosynthetic capability to express either CP5 or CP8 and an understanding of the relationship between CP genotype/phenotype and S. aureus epidemiology is valuable. Using whole genome sequencing, the clonal relatedness and CP genotype were evaluated for disease-associated S. aureus isolates selected from the Tigecycline Evaluation and Surveillance Trial (T.E.S.T) to represent different geographic regions in the United States (US) during 2004 and 2009–10. Thirteen prominent clonal complexes (CC) were identified, with CC5, 8, 30 and 45 representing >80% of disease isolates. CC5 and CC8 isolates were CP type 5 and, CC30 and CC45 isolates were CP type 8. Representative isolates from prevalent CC were susceptible to in vitro opsonophagocytic killing elicited by anti-CP antibodies, demonstrating that susceptibility to opsonic killing is not linked to the genetic lineage. However, as not all S. aureus isolates may express CP, isolates representing the diversity of disease isolates were assessed for CP production. While approximately 35% of isolates (primarily CC8) did not express CP in vitro, CP expression could be clearly demonstrated in vivo for 77% of a subset of these isolates (n = 20) despite the presence of mutations within the capsule operon. CP expression in vivo was also confirmed indirectly by measuring an increase in CP specific antibodies in mice infected with CP5 or CP8 isolates. Detection of antigen expression in vivo in relevant disease states is important to support the inclusion of these antigens in vaccines. Our findings confirm the validity of CP as vaccine targets and the potential of CP-based vaccines to contribute to S. aureus disease prevention.
Collapse
Affiliation(s)
- Naglaa Mohamed
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Yekaterina Timofeyeva
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Dorota Jamrozy
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Eduardo Rojas
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Li Hao
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | | | - Julio Hawkins
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Guy Singh
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Bing Cai
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Paul Liberator
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Shite Sebastian
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Robert G. K. Donald
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Ingrid L. Scully
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - C. Hal Jones
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - C. Buddy Creech
- Vanderbilt Vaccine Research Program, Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Isaac Thomsen
- Vanderbilt Vaccine Research Program, Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Sharon J. Peacock
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kathrin U. Jansen
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | | | - Annaliesa S. Anderson
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
- * E-mail:
| |
Collapse
|
11
|
Kaundinya CR, Savithri HS, Krishnamurthy Rao K, Balaji PV. In vitro characterization of N-terminal truncated EpsC from Bacillus subtilis 168, a UDP-N-acetylglucosamine 4,6-dehydratase. Arch Biochem Biophys 2018; 657:78-88. [PMID: 30222950 DOI: 10.1016/j.abb.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 12/16/2022]
Abstract
Bacillus subtilis 168 EpsC is annotated as "Probable polysaccharide biosynthesis protein" in the SwissProt database. epsC is part of the eps operon, thought to be involved in the biosynthesis of exopolymeric substances (EPS). The present study was undertaken to determine the molecular function of EpsC. Sequence analysis of EpsC suggested the presence of a transmembrane domain. Two N-terminal deletion mutants in which residues 1-89 (EpsC89) and 1-115 (EpsC115) are deleted were cloned and overexpressed. Enzyme activity and substrate preferences were investigated by reverse phase HPLC, surface plasmon resonance (SPR) spectroscopy and absorption spectroscopy. These data show that EpsC has UDP-GlcNAc 4,6-dehydratase activity in vitro. Purified recombinant proteins were found to utilise UDP-Glc and TDP-Glc also as substrates. In addition, EpsC115 could utilise UDP-Gal and UDP-GalNAc as substrates whereas EpsC89 could only bind these two sugar nucleotides. These results show that deletion of a longer N-terminal region broadens substrate specificity. These broadened specificity is perhaps an outcome of the deletion of the putative transmembrane domain and may not be present in vivo. EpsC, together with the aminotransferase EpsN (Kaundinya CR et al., Glycobiology, 2018) and acetyltransferase EpsM (unpublished data), appears to be involved in the biosynthesis of N,N'-diacetylbacillosamine.
Collapse
Affiliation(s)
- Chinmayi R Kaundinya
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Handanahal S Savithri
- Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bengaluru, 560012, India
| | - K Krishnamurthy Rao
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Petety V Balaji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| |
Collapse
|
12
|
Gattu S, Crihfield CL, Lu G, Bwanali L, Veltri LM, Holland LA. Advances in enzyme substrate analysis with capillary electrophoresis. Methods 2018; 146:93-106. [PMID: 29499329 PMCID: PMC6098732 DOI: 10.1016/j.ymeth.2018.02.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 02/06/2023] Open
Abstract
Capillary electrophoresis provides a rapid, cost-effective platform for enzyme and substrate characterization. The high resolution achievable by capillary electrophoresis enables the analysis of substrates and products that are indistinguishable by spectroscopic techniques alone, while the small volume requirement enables analysis of enzymes or substrates in limited supply. Furthermore, the compatibility of capillary electrophoresis with various detectors makes it suitable for KM determinations ranging from nanomolar to millimolar concentrations. Capillary electrophoresis fundamentals are discussed with an emphasis on the separation mechanisms relevant to evaluate sets of substrate and product that are charged, neutral, and even chiral. The basic principles of Michaelis-Menten determinations are reviewed and the process of translating capillary electrophoresis electropherograms into a Michaelis-Menten curve is outlined. The conditions that must be optimized in order to couple off-line and on-line enzyme reactions with capillary electrophoresis separations, such as incubation time, buffer pH and ionic strength, and temperature, are examined to provide insight into how the techniques can be best utilized. The application of capillary electrophoresis to quantify enzyme inhibition, in the form of KI or IC50 is detailed. The concept and implementation of the immobilized enzyme reactor is described as a means to increase enzyme stability and reusability, as well as a powerful tool for screening enzyme substrates and inhibitors. Emerging techniques focused on applying capillary electrophoresis as a rapid assay to obtain structural identification or sequence information about a substrate and in-line digestions of peptides and proteins coupled to mass spectrometry analyses are highlighted.
Collapse
Affiliation(s)
- Srikanth Gattu
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States
| | - Cassandra L Crihfield
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States
| | - Grace Lu
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States
| | - Lloyd Bwanali
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States
| | - Lindsay M Veltri
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States
| | - Lisa A Holland
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506, United States.
| |
Collapse
|
13
|
A functional and genetic overview of exopolysaccharides produced by Lactobacillus plantarum. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.05.060] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
|
14
|
From Immunologically Archaic to Neoteric Glycovaccines. Vaccines (Basel) 2017; 5:vaccines5010004. [PMID: 28134792 PMCID: PMC5371740 DOI: 10.3390/vaccines5010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/14/2016] [Accepted: 01/22/2017] [Indexed: 12/13/2022] Open
Abstract
Polysaccharides (PS) are present in the outermost surface of bacteria and readily come in contact with immune cells. They interact with specific antibodies, which in turn confer protection from infections. Vaccines with PS from pneumococci, meningococci, Haemophilus influenzae type b, and Salmonella typhi may be protective, although with the important constraint of failing to generate permanent immunological memory. This limitation has in part been circumvented by conjugating glycovaccines to proteins that stimulate T helper cells and facilitate the establishment of immunological memory. Currently, protection evoked by conjugated PS vaccines lasts for a few years. The same approach failed with PS from staphylococci, Streptococcus agalactiae, and Klebsiella. All those germs cause severe infections in humans and often develop resistance to antibiotic therapy. Thereby, prevention is of increasing importance to better control outbreaks. As only 23 of more than 90 pneumococcal serotypes and 4 of 13 clinically relevant Neisseria meningitidis serogroups are covered by available vaccines there is still tremendous clinical need for PS vaccines. This review focuses on glycovaccines and the immunological mechanisms for their success or failure. We discuss recent advances that may facilitate generation of high affinity anti-PS antibodies and confer specific immunity and long-lasting protection.
Collapse
|
15
|
Liu B, Park S, Thompson CD, Li X, Lee JC. Antibodies to Staphylococcus aureus capsular polysaccharides 5 and 8 perform similarly in vitro but are functionally distinct in vivo. Virulence 2016; 8:859-874. [PMID: 27936346 DOI: 10.1080/21505594.2016.1270494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The capsular polysaccharide (CP) produced by Staphylococcus aureus is a virulence factor that allows the organism to evade uptake and killing by host neutrophils. Polyclonal antibodies to the serotype 5 (CP5) and type 8 (CP8) capsular polysaccharides are opsonic and protect mice against experimental bacteremia provoked by encapsulated staphylococci. Thus, passive immunotherapy using CP antibodies has been considered for the prevention or treatment of invasive antibiotic-resistant S. aureus infections. In this report, we generated monoclonal antibodies (mAbs) against S. aureus CP5 or CP8. Backbone specific mAbs reacted with native and O-deacetylated CPs, whereas O-acetyl specific mAbs reacted only with native CPs. Reference strains of S. aureus and a selection of clinical isolates reacted by colony immunoblot with the CP5 and CP8 mAbs in a serotype-specific manner. The mAbs mediated in vitro CP type-specific opsonophagocytic killing of S. aureus strains, and mice passively immunized with CP5 mAbs were protected against S. aureus bacteremia. Neither CP8-specific mAbs or polyclonal antibodies protected mice against bacteremia provoked by serotype 8 S. aureus clinical isolates, although these same antibodies did protect against a serotype 5 S. aureus strain genetically engineered to produce CP8. We detected soluble CP8 in culture supernatants of serotype 8 clinical isolates and in the plasma of infected animals. Serotype 5 S. aureus released significantly less soluble CP5 in vitro and in vivo. The release of soluble CP8 by S. aureus may contribute to the inability of CP8 vaccines or antibodies to protect against serotype 8 staphylococcal infections.
Collapse
Affiliation(s)
- Bo Liu
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Saeyoung Park
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Christopher D Thompson
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Xue Li
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA.,b Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing , China
| | - Jean C Lee
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| |
Collapse
|
16
|
Miller CL, Van Laar TA, Chen T, Karna SLR, Chen P, You T, Leung KP. Global transcriptome responses including small RNAs during mixed-species interactions with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Microbiologyopen 2016; 6. [PMID: 27868360 PMCID: PMC5458535 DOI: 10.1002/mbo3.427] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus mixed‐species biofilm infections are more resilient to biocide attacks compared to their single‐species counterparts. Therefore, this study used an in vitro model recapitulating bacterial burdens seen in in vivo infections to investigate the interactions of P. aeruginosa and S. aureus in biofilms. RNA sequencing (RNA‐seq) was utilized to identify the entire genomic response, both open reading frames (ORFs) and small RNAs (sRNAs), of each species. Using competitive indexes, transposon mutants validated uncharacterized PA1595 of P. aeruginosa and Panton–Valentine leukocidin ORFs of S. aureus are required for competitive success. Assessing spent media on biofilm development determined that the effects of these ORFs are not solely mediated by mechanisms of secretion. Unlike PA1595, leukocidin (lukS‐PV) mutants of S. aureus lack a competitive advantage through contact‐mediated mechanisms demonstrated by cross‐hatch assays. RNA‐seq results suggested that during planktonic mixed‐species growth there is a robust genomic response or active combat from both pathogens until a state of equilibrium is reached during the maturation of a biofilm. In mixed‐species biofilms, P. aeruginosa differentially expressed only 0.3% of its genome, with most ORFs necessary for growth and biofilm development, whereas S. aureus modulated approximately 5% of its genome, with ORFs suggestive of a phenotype of increased virulence and metabolic quiescence. Specific expression of characterized sRNAs aligned with the genomic response to presumably coordinate the adaptive changes necessary for this homeostatic mixed‐species biofilm and sRNAs may provide viable foci for the design of future therapeutics.
Collapse
Affiliation(s)
- Christine L Miller
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tricia A Van Laar
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tsute Chen
- The Forsyth Institute, Cambridge, MA, USA
| | - S L Rajasekhar Karna
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Ping Chen
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Tao You
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| | - Kai P Leung
- Microbiology Branch, Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, Institute of Surgical Research, JBSA Fort Sam Houston, TX, USA
| |
Collapse
|
17
|
Fiene A, Baqi Y, Malik EM, Newton P, Li W, Lee SY, Hartland EL, Müller CE. Inhibitors for the bacterial ectonucleotidase Lp1NTPDase from Legionella pneumophila. Bioorg Med Chem 2016; 24:4363-4371. [DOI: 10.1016/j.bmc.2016.07.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/15/2016] [Indexed: 12/29/2022]
|
18
|
Dynamics of Mutations during Development of Resistance by Pseudomonas aeruginosa against Five Antibiotics. Antimicrob Agents Chemother 2016; 60:4229-36. [PMID: 27139485 DOI: 10.1128/aac.00434-16] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/26/2016] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes considerable morbidity and mortality, specifically during intensive care. Antibiotic-resistant variants of this organism are more difficult to treat and cause substantial extra costs compared to susceptible strains. In the laboratory, P. aeruginosa rapidly developed resistance to five medically relevant antibiotics upon exposure to stepwise increasing concentrations. At several time points during the acquisition of resistance, samples were taken for whole-genome sequencing. The increase in the MIC of ciprofloxacin was linked to specific mutations in gyrA, parC, and gyrB, appearing sequentially. In the case of tobramycin, mutations in fusA, HP02880, rplB, and capD were induced. The MICs of the beta-lactam compounds meropenem and ceftazidime and the combination of piperacillin and tazobactam correlated linearly with beta-lactamase activity but not always with individual mutations. The genes that were mutated during the development of beta-lactam resistance differed for each antibiotic. A quantitative relationship between the frequency of mutations and the increase in resistance could not be established for any of the antibiotics. When the adapted strains are grown in the absence of the antibiotic, some mutations remained and others were reversed, but this reversal did not necessarily lower the MIC. The increased MIC came at the cost of moderately reduced cellular functions or a somewhat lower growth rate. In all cases except ciprofloxacin, the increase in resistance seems to be the result of complex interactions among several cellular systems rather than individual mutations.
Collapse
|
19
|
Li W, Zech I, Gieselmann V, Müller CE. A capillary electrophoresis method with dynamic pH junction stacking for the monitoring of cerebroside sulfotransferase. J Chromatogr A 2015; 1407:222-7. [DOI: 10.1016/j.chroma.2015.06.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 06/16/2015] [Accepted: 06/19/2015] [Indexed: 12/27/2022]
|
20
|
USA300 and USA500 clonal lineages of Staphylococcus aureus do not produce a capsular polysaccharide due to conserved mutations in the cap5 locus. mBio 2015; 6:mBio.02585-14. [PMID: 25852165 PMCID: PMC4453534 DOI: 10.1128/mbio.02585-14] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The surface capsular polysaccharide (CP) is a virulence factor that has been used as an antigen in several successful vaccines against bacterial pathogens. A vaccine has not yet been licensed against Staphylococcus aureus, although two multicomponent vaccines that contain CP antigens are in clinical trials. In this study, we evaluated CP production in USA300 methicillin-resistant S. aureus (MRSA) isolates that have become the predominant community-associated MRSA clones in the United States. We found that all 167 USA300 MRSA and 50 USA300 methicillin-susceptible S. aureus (MSSA) isolates were CP negative (CP−). Moreover, all 16 USA500 isolates, which have been postulated to be the progenitor lineage of USA300, were also CP−. Whole-genome sequence analysis of 146 CP− USA300 MRSA isolates revealed they all carry a cap5 locus with 4 conserved mutations compared with strain Newman. Genetic complementation experiments revealed that three of these mutations (in the cap5 promoter, cap5D nucleotide 994, and cap5E nucleotide 223) ablated CP production in USA300 and that Cap5E75 Asp, located in the coenzyme-binding domain, is essential for capsule production. All but three USA300 MSSA isolates had the same four cap5 mutations found in USA300 MRSA isolates. Most isolates with a USA500 pulsotype carried three of these four USA300-specific mutations, suggesting the fourth mutation occurred in the USA300 lineage. Phylogenetic analysis of the cap loci of our USA300 isolates as well as publicly available genomes from 41 other sequence types revealed that the USA300-specific cap5 mutations arose sequentially in S. aureus in a common ancestor of USA300 and USA500 isolates. The USA300 MRSA clone emerged as a community-associated pathogen in the United States nearly 20 years ago. Since then, it has rapidly disseminated and now causes health care-associated infections. This study shows that the CP-negative (CP−) phenotype has persisted among USA300 isolates and is a universal and characteristic trait of this highly successful MRSA lineage. It is important to note that a vaccine consisting solely of CP antigens would not likely demonstrate high efficacy in the U.S. population, where about half of MRSA isolates comprise USA300. Moreover, conversion of a USA300 strain to a CP-positive (CP+) phenotype is unlikely in vivo or in vitro since it would require the reversion of 3 mutations. We have also established that USA300 MSSA isolates and USA500 isolates are CP− and provide new insight into the evolution of the USA300 and USA500 lineages.
Collapse
|
21
|
Weidenmaier C, Lee JC. Structure and Function of Surface Polysaccharides of Staphylococcus aureus. Curr Top Microbiol Immunol 2015; 409:57-93. [PMID: 26728067 DOI: 10.1007/82_2015_5018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The major surface polysaccharides of Staphylococcus aureus include the capsular polysaccharide (CP), cell wall teichoic acid (WTA), and polysaccharide intercellular adhesin/poly-β(1-6)-N-acetylglucosamine (PIA/PNAG). These glycopolymers are important components of the staphylococcal cell envelope, but none of them is essential to S. aureus viability and growth in vitro. The overall biosynthetic pathways of CP, WTA, and PIA/PNAG have been elucidated, and the functions of most of the biosynthetic enzymes have been demonstrated. Because S. aureus CP and WTA (but not PIA/PNAG) utilize a common cell membrane lipid carrier (undecaprenyl-phosphate) that is shared by the peptidoglycan biosynthesis pathway, there is evidence that these processes are highly integrated and temporally regulated. Regulatory elements that control glycopolymer biosynthesis have been described, but the cross talk that orchestrates the biosynthetic pathways of these three polysaccharides remains largely elusive. CP, WTA, and PIA/PNAG each play distinct roles in S. aureus colonization and the pathogenesis of staphylococcal infection. However, they each promote bacterial evasion of the host immune defences, and WTA is being explored as a target for antimicrobial therapeutics. All the three glycopolymers are viable targets for immunotherapy, and each (conjugated to a carrier protein) is under evaluation for inclusion in a multivalent S. aureus vaccine. Future research findings that increase our understanding of these surface polysaccharides, how the bacterial cell regulates their expression, and their biological functions will likely reveal new approaches to controlling this important bacterial pathogen.
Collapse
Affiliation(s)
- Christopher Weidenmaier
- Interfaculty Institute for Microbiology and Infection Medicine Tübingen, University of Tübingen and German Center for Infection Research, Tübingen, Germany
| | - Jean C Lee
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| |
Collapse
|