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Ballah FM, Hoque MN, Islam MS, Faisal GM, Rahman AMMT, Khatun MM, Rahman M, Hassan J, Rahman MT. Genomic Insights of a Methicillin-Resistant Biofilm-Producing Staphylococcus aureus Strain Isolated From Food Handlers. BIOMED RESEARCH INTERNATIONAL 2024; 2024:5516117. [PMID: 39071244 PMCID: PMC11283335 DOI: 10.1155/2024/5516117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/27/2024] [Accepted: 06/24/2024] [Indexed: 07/30/2024]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm-producing and multidrug-resistant (MDR) S. aureus MTR_BAU_H1 strain through whole-genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers' hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm-former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta-lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first-ever WGS-based study of a strong biofilm-producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals.
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Affiliation(s)
- Fatimah Muhammad Ballah
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - M. Nazmul Hoque
- Molecular Biology and Bioinformatics LaboratoryDepartment of GynaecologyObstetrics and Reproductive HealthBangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Md. Saiful Islam
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
- Department of Animal SciencesUniversity of California-Davis, Davis, California CA 95616, USA
| | - Golam Mahbub Faisal
- Molecular Biology and Bioinformatics LaboratoryDepartment of GynaecologyObstetrics and Reproductive HealthBangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | | | - Mst. Minara Khatun
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Marzia Rahman
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Jayedul Hassan
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Md. Tanvir Rahman
- Department of Microbiology and HygieneFaculty of Veterinary ScienceBangladesh Agricultural University, Mymensingh 2202, Bangladesh
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Peran JE, Salvador-Reyes LA. Modified oxylipins as inhibitors of biofilm formation in Staphylococcus epidermidis. Front Pharmacol 2024; 15:1379643. [PMID: 38846101 PMCID: PMC11153713 DOI: 10.3389/fphar.2024.1379643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/23/2024] [Indexed: 06/09/2024] Open
Abstract
New approaches to combating microbial drug resistance are being sought, with the discovery of biofilm inhibitors considered as alternative arsenal for treating infections. Natural products have been at the forefront of antimicrobial discovery and serve as inspiration for the design of new antibiotics. We probed the potency, selectivity, and mechanism of anti-biofilm activity of modified oxylipins inspired by the marine natural product turneroic acid. Structure-activity relationship (SAR) evaluation revealed the importance of the trans-epoxide moiety, regardless of the position, for inhibiting biofilm formation. trans-12,13-epoxyoctadecanoic acid (1) and trans-9,10 epoxyoctadecanoic acid (4) selectively target the early stage of biofilm formation, with no effect on planktonic cells. These compounds interrupt the formation of a protective polysaccharide barrier by significantly upregulating the ica operon's transcriptional repressor. This was corroborated by docking experiment with SarA and scanning electron micrographs showing reduced biofilm aggregates and the absence of thread-like structures of extrapolymeric substances. In silico evaluation revealed that 1 and 4 can interfere with the AgrA-mediated communication language in Staphylococci, typical to the diffusible signal factor (DSF) capacity of lipophilic chains.
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Affiliation(s)
| | - Lilibeth A. Salvador-Reyes
- Marine Science Institute, College of Science, University of the Philippines Diliman, Quezon City, Philippines
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Lei MG, Jorgenson MA, Robbs EJ, Black IM, Archer-Hartmann S, Shalygin S, Azadi P, Lee CY. Characterization of Ssc, an N-acetylgalactosamine-containing Staphylococcus aureus surface polysaccharide. J Bacteriol 2024; 206:e0004824. [PMID: 38712944 PMCID: PMC11112989 DOI: 10.1128/jb.00048-24] [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: 02/11/2024] [Accepted: 04/08/2024] [Indexed: 05/08/2024] Open
Abstract
Whole genome sequencing has revealed that the genome of Staphylococcus aureus possesses an uncharacterized 5-gene operon (SAOUHSC_00088-00092 in strain 8325 genome) that encodes factors with functions related to polysaccharide biosynthesis and export, indicating the existence of a new extracellular polysaccharide species. We designate this locus as ssc for staphylococcal surface carbohydrate. We found that the ssc genes were weakly expressed and highly repressed by the global regulator MgrA. To characterize Ssc, Ssc was heterologously expressed in Escherichia coli and extracted by heat treatment. Ssc was also conjugated to AcrA from Campylobacter jejuni in E. coli using protein glycan coupling technology (PGCT). Analysis of the heat-extracted Ssc and the purified Ssc-AcrA glycoconjugate by tandem mass spectrometry revealed that Ssc is likely a polymer consisting of N-acetylgalactosamine. We further demonstrated that the expression of the ssc genes in S. aureus affected phage adsorption and susceptibility, suggesting that Ssc is surface-exposed. IMPORTANCE Surface polysaccharides play crucial roles in the biology and virulence of bacterial pathogens. Staphylococcus aureus produces four major types of polysaccharides that have been well-characterized. In this study, we identified a new surface polysaccharide containing N-acetylgalactosamine (GalNAc). This marks the first report of GalNAc-containing polysaccharide in S. aureus. Our discovery lays the groundwork for further investigations into the chemical structure, surface location, and role in pathogenesis of this new polysaccharide.
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Affiliation(s)
- Mei G. Lei
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Matthew A. Jorgenson
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Emily J. Robbs
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ian M. Black
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | | | - Sergei Shalygin
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Chia Y. Lee
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Schwartbeck B, Rumpf CH, Hait RJ, Janssen T, Deiwick S, Schwierzeck V, Mellmann A, Kahl BC. Various mutations in icaR, the repressor of the icaADBC locus, occur in mucoid Staphylococcus aureus isolates recovered from the airways of people with cystic fibrosis. Microbes Infect 2024; 26:105306. [PMID: 38316375 DOI: 10.1016/j.micinf.2024.105306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/16/2024] [Accepted: 01/29/2024] [Indexed: 02/07/2024]
Abstract
Staphylococcus aureus is one of the major pathogens isolated from the airways of people with cystic fibrosis (pwCF). Recently, we described a mucoid S. aureus phenotype from respiratory specimens of pwCF, which constitutively overproduced biofilm that consisted of polysaccharide intercellular adhesin (PIA) due to a 5bp-deletion (5bp-del) in the intergenic region of the intercellular adhesin (ica) locus. Since we were not able to identify the 5bp-del in mucoid isolates of two pwCF with long-term S. aureus persistence and in a number of mucoid isolates of pwCF from a prospective multicenter study, these strains were (i) characterized phenotypically, (ii) investigated for biofilm formation, and (iii) molecular typed by spa-sequence typing. To screen for mutations responsible for mucoidy, the ica operon of all mucoid isolates was analyzed by Sanger sequencing. Whole genome sequencing was performed for selected isolates. For all mucoid isolates without the 5 bp-del, various mutations in icaR, which is the transcriptional repressor of the icaADBC operon. Mucoid and non-mucoid strains belonged to the same spa-type. Transformation of PIA-overproducing S. aureus with a vector expressing the intact icaR gene restored the non-mucoid phenotype. Altogether, we demonstrated a new mechanism for the emergence of mucoid S. aureus isolates of pwCF.
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Affiliation(s)
- Bianca Schwartbeck
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | - Christine H Rumpf
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | | | - Timo Janssen
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | - Susanne Deiwick
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | | | | | - Barbara C Kahl
- Institute of Medical Microbiology, University Hospital Muenster, Germany.
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5
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Ruijgrok G, Wu DY, Overkleeft HS, Codée JDC. Synthesis and application of bacterial exopolysaccharides. Curr Opin Chem Biol 2024; 78:102418. [PMID: 38134611 DOI: 10.1016/j.cbpa.2023.102418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/02/2023] [Accepted: 12/03/2023] [Indexed: 12/24/2023]
Abstract
Exopolysaccharides are produced and excreted by bacteria in the generation of biofilms to provide a protective environment. These polysaccharides are generally generated as heterogeneous polymers of varying length, featuring diverse substitution patterns. To obtain well-defined fragments of these polysaccharides, organic synthesis often is the method of choice, as it allows for full control over chain length and the installation of a pre-determined substitution pattern. This review presents several recent syntheses of exopolysaccharide fragments of Pseudomonas aeruginosa and Staphylococcus aureus and illustrates how these have been used to study biosynthesis enzymes and generate synthetic glycoconjugate vaccines.
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Affiliation(s)
- Gijs Ruijgrok
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Dung-Yeh Wu
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands.
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Low KE, Gheorghita AA, Tammam SD, Whitfield GB, Li YE, Riley LM, Weadge JT, Caldwell SJ, Chong PA, Walvoort MTC, Kitova EN, Klassen JS, Codée JDC, Howell PL. Pseudomonas aeruginosa AlgF is a protein-protein interaction mediator required for acetylation of the alginate exopolysaccharide. J Biol Chem 2023; 299:105314. [PMID: 37797696 PMCID: PMC10641220 DOI: 10.1016/j.jbc.2023.105314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
Enzymatic modifications of bacterial exopolysaccharides enhance immune evasion and persistence during infection. In the Gram-negative opportunistic pathogen Pseudomonas aeruginosa, acetylation of alginate reduces opsonic killing by phagocytes and improves reactive oxygen species scavenging. Although it is well known that alginate acetylation in P. aeruginosa requires AlgI, AlgJ, AlgF, and AlgX, how these proteins coordinate polymer modification at a molecular level remains unclear. Here, we describe the structural characterization of AlgF and its protein interaction network. We characterize direct interactions between AlgF and both AlgJ and AlgX in vitro and demonstrate an association between AlgF and AlgX, as well as AlgJ and AlgI, in P. aeruginosa. We determine that AlgF does not exhibit acetylesterase activity and is unable to bind to polymannuronate in vitro. Therefore, we propose that AlgF functions to mediate protein-protein interactions between alginate acetylation enzymes, forming the periplasmic AlgJFXK (AlgJ-AlgF-AlgX-AlgK) acetylation and export complex required for robust biofilm formation.
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Affiliation(s)
- Kristin E Low
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andreea A Gheorghita
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Stephanie D Tammam
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gregory B Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yancheng E Li
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Laura M Riley
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Joel T Weadge
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shane J Caldwell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - P Andrew Chong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Elena N Kitova
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - John S Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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7
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Han J, Poma A. Molecular Targets for Antibody-Based Anti-Biofilm Therapy in Infective Endocarditis. Polymers (Basel) 2022; 14:3198. [PMID: 35956712 PMCID: PMC9370930 DOI: 10.3390/polym14153198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Infective endocarditis (IE) is a heart disease caused by the infection of heart valves, majorly caused by Staphilococcus aureus. IE is initiated by bacteria entering the blood circulation in favouring conditions (e.g., during invasive procedures). So far, the conventional antimicrobial strategies based on the usage of antibiotics remain the major intervention for treating IE. Nevertheless, the therapeutic efficacy of antibiotics in IE is limited not only by the bacterial drug resistance, but also by the formation of biofilms, which resist the penetration of antibiotics into bacterial cells. To overcome these drawbacks, the development of anti-biofilm treatments that can expose bacteria and make them more susceptible to the action of antibiotics, therefore resulting in reduced antimicrobial resistance, is urgently required. A series of anti-biofilm strategies have been developed, and this review will focus in particular on the development of anti-biofilm antibodies. Based on the results previously reported in the literature, several potential anti-biofilm targets are discussed, such as bacterial adhesins, biofilm matrix and bacterial toxins, covering their antigenic properties (with the identification of potential promising epitopes), functional mechanisms, as well as the antibodies already developed against these targets and, where feasible, their clinical translation.
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Affiliation(s)
- Jiahe Han
- UCL Institute of Cardiovascular Science, The Rayne Building, 5 University Street, London WC1E 6JF, UK
| | - Alessandro Poma
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, Royal Free Hospital, UCL Medical School, Rowland Hill Street, London NW3 2PF, UK
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8
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Wang H, Chen D, Lu H. Anti-bacterial monoclonal antibodies: next generation therapy against superbugs. Appl Microbiol Biotechnol 2022; 106:3957-3972. [PMID: 35648146 DOI: 10.1007/s00253-022-11989-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 12/19/2022]
Abstract
Prior to the nineteenth century, infectious disease was one of the leading causes of death. Human life expectancy has roughly doubled over the past century as a result of the development of antibiotics and vaccines. However, the emergence of antibiotic-resistant superbugs brings new challenges. The side effects of broad-spectrum antibiotics, such as causing antimicrobial resistance and destroying the normal flora, often limit their applications. Furthermore, the development of new antibiotics has lagged far behind the emergence and spread of antibiotic resistance. On the other hand, the genome complexity of bacteria makes it difficult to create effective vaccines. Therefore, novel therapeutic agents in supplement to antibiotics and vaccines are urgently needed to improve the treatment of infections. In recent years, monoclonal antibodies (mAbs) have achieved remarkable clinical success in a variety of fields. In the treatment of infectious diseases, mAbs can play functions through multiple mechanisms, including toxins neutralization, virulence factors inhibition, complement-mediated killing activity, and opsonic phagocytosis. Toxins and bacterial surface components are good targets to generate antibodies against. The U.S. FDA has approved three monoclonal antibody drugs, and there are numerous candidates in the preclinical or clinical trial stages. This article reviews recent advances in the research and development of anti-bacterial monoclonal antibody drugs in order to provide a valuable reference for future studies in this area. KEY POINTS: • Novel drugs against antibiotic-resistant superbugs are urgently required • Monoclonal antibodies can treat bacterial infections through multiple mechanisms • There are many anti-bacterial monoclonal antibodies developed in recent years and some candidates have entered the preclinical or clinical stages of development.
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Affiliation(s)
- Hui Wang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Daijie Chen
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Huili Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
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9
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Dollery SJ, Harro JM, Wiggins TJ, Wille BP, Kim PC, Tobin JK, Bushnell RV, Tasker NJPER, MacLeod DA, Tobin GJ. Select Whole-Cell Biofilm-Based Immunogens Protect against a Virulent Staphylococcus Isolate in a Stringent Implant Model of Infection. Vaccines (Basel) 2022; 10:vaccines10060833. [PMID: 35746441 PMCID: PMC9231243 DOI: 10.3390/vaccines10060833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/13/2022] [Accepted: 05/19/2022] [Indexed: 12/12/2022] Open
Abstract
Many microbes of concern to human health remain without vaccines. We have developed a whole-microbe inactivation technology that enables us to rapidly inactivate large quantities of a pathogen while retaining epitopes that were destroyed by previous inactivation methods. The method that we call UVC-MDP inactivation can be used to make whole-cell vaccines with increased potency. We and others are exploring the possibility of using improved irradiation-inactivation technologies to develop whole-cell vaccines for numerous antibiotic-resistant microbes. Here, we apply UVC-MDP to produce candidate MRSA vaccines which we test in a stringent tibia implant model of infection challenged with a virulent MSRA strain. We report high levels of clearance in the model and observe a pattern of protection that correlates with the immunogen protein profile used for vaccination.
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Affiliation(s)
- Stephen J. Dollery
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
- Correspondence:
| | - Janette M. Harro
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (J.M.H.); (B.P.W.); (P.C.K.)
| | - Taralyn J. Wiggins
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
| | - Brendan P. Wille
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (J.M.H.); (B.P.W.); (P.C.K.)
| | - Peter C. Kim
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA; (J.M.H.); (B.P.W.); (P.C.K.)
| | - John K. Tobin
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
| | - Ruth V. Bushnell
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
| | - Naomi J. P. E. R. Tasker
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
| | - David A. MacLeod
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
| | - Gregory J. Tobin
- Biological Mimetics, Inc., Frederick, MD 21702, USA; (T.J.W.); (J.K.T.); (R.V.B.); (N.J.P.E.R.T.); (D.A.M.); (G.J.T.)
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10
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Nguyen TK, Peyrusson F, Siala W, Pham NH, Nguyen HA, Tulkens PM, Van Bambeke F. Activity of Moxifloxacin Against Biofilms Formed by Clinical Isolates of Staphylococcus aureus Differing by Their Resistant or Persister Character to Fluoroquinolones. Front Microbiol 2021; 12:785573. [PMID: 34975808 PMCID: PMC8715871 DOI: 10.3389/fmicb.2021.785573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus biofilms are poorly responsive to antibiotics. Underlying reasons include a matrix effect preventing drug access to embedded bacteria, or the presence of dormant bacteria with reduced growth rate. Using 18 clinical isolates previously characterized for their moxifloxacin-resistant and moxifloxacin-persister character in stationary-phase culture, we studied their biofilm production and matrix composition and the anti-biofilm activity of moxifloxacin. Biofilms were grown in microtiter plates and their abundance quantified by crystal violet staining and colony counting; their content in polysaccharides, extracellular DNA and proteins was measured. Moxifloxacin activity was assessed after 24 h of incubation with a broad range of concentrations to establish full concentration-response curves. All clinical isolates produced more biofilm biomass than the reference strain ATCC 25923, the difference being more important for those with high relative persister fractions to moxifloxacin, most of which being also resistant. High biofilm producers expressed icaA to higher levels, enriching the matrix in polysaccharides. Moxifloxacin was less potent against biofilms from clinical isolates than from ATCC 25923, especially against moxifloxacin-resistant isolates with high persister fractions, which was ascribed to a lower concentration of moxifloxacin in these biofilms. Time-kill curves in biofilms revealed the presence of a moxifloxacin-tolerant subpopulation, with low multiplication capacity, whatever the persister character of the isolate. Thus, moxifloxacin activity depends on its local concentration in biofilm, which is reduced in most isolates with high-relative persister fractions due to matrix effects, and insufficient to kill resistant isolates due to their high MIC.
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Affiliation(s)
- Tiep K. Nguyen
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
- Department of Pharmaceutical Industry, Hanoi University of Pharmacy, Hanoi, Vietnam
| | - Frédéric Peyrusson
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Wafi Siala
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Nhung H. Pham
- Department of Microbiology, Bach Mai Hospital, Hanoi, Vietnam
| | - Hoang A. Nguyen
- The National Center for Drug Information and Adverse Drug Reactions Monitoring, Hanoi University of Pharmacy, Hanoi, Vietnam
| | - Paul M. Tulkens
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Françoise Van Bambeke
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
- *Correspondence: Françoise Van Bambeke,
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Synthetic carbohydrate-based cell wall components from Staphylococcus aureus. DRUG DISCOVERY TODAY. TECHNOLOGIES 2021; 38:35-43. [PMID: 34895639 DOI: 10.1016/j.ddtec.2021.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/17/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022]
Abstract
Glycopolymers are found surrounding the outer layer of many bacterial species. The first uses as immunogenic component in vaccines are reported since the beginning of the XX century, but it is only in the last decades that glycoconjugate based vaccines have been effectively applied for controlling and preventing several infectious diseases, such as H. influenzae type b (Hib), N. meningitidis, S. pneumoniae or group B Streptococcus. Methicillin resistant S. aureus (MRSA) strains has been appointed by the WHO as one of those pathogens, for which new treatments are urgently needed. Herein we present an overview of the carbohydrate-based cell wall polymers associated with different S. aureus strains and the related affords to deliver well-defined fragments through synthetic chemistry.
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Cheung GYC, Bae JS, Otto M. Pathogenicity and virulence of Staphylococcus aureus. Virulence 2021; 12:547-569. [PMID: 33522395 PMCID: PMC7872022 DOI: 10.1080/21505594.2021.1878688] [Citation(s) in RCA: 457] [Impact Index Per Article: 152.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. This pathogen can cause a wide variety of diseases, ranging from moderately severe skin infections to fatal pneumonia and sepsis. Treatment of S. aureus infections is complicated by antibiotic resistance and a working vaccine is not available. There has been ongoing and increasing interest in the extraordinarily high number of toxins and other virulence determinants that S. aureus produces and how they impact disease. In this review, we will give an overview of how S. aureus initiates and maintains infection and discuss the main determinants involved. A more in-depth understanding of the function and contribution of S. aureus virulence determinants to S. aureus infection will enable us to develop anti-virulence strategies to counteract the lack of an anti-S. aureus vaccine and the ever-increasing shortage of working antibiotics against this important pathogen.
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Affiliation(s)
- Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Justin S. Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
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13
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Liu J, Madec JY, Bousquet-Mélou A, Haenni M, Ferran AA. Destruction of Staphylococcus aureus biofilms by combining an antibiotic with subtilisin A or calcium gluconate. Sci Rep 2021; 11:6225. [PMID: 33737602 PMCID: PMC7973569 DOI: 10.1038/s41598-021-85722-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 02/28/2021] [Indexed: 12/14/2022] Open
Abstract
In S. aureus biofilms, bacteria are embedded in a matrix of extracellular polymeric substances (EPS) and are highly tolerant to antimicrobial drugs. We thus sought to identify non-antibiotic substances with broad-spectrum activity able to destroy the EPS matrix and enhance the effect of antibiotics on embedded biofilm bacteria. Among eight substances tested, subtilisin A (0.01 U/mL) and calcium gluconate (CaG, Ca2+ 1.25 mmol/L) significantly reduced the biomass of biofilms formed by at least 21/24 S. aureus isolates. Confocal laser scanning microscopy confirmed that they both eliminated nearly all the proteins and PNAG from the matrix. By contrast, antibiotics alone had nearly no effect on biofilm biomass and the selected one (oxytetracycline-OTC) could only slightly reduce biofilm bacteria. The combination of OTC with CaG or subtilisin A led to an additive reduction (average of 2 log10 CFU/mL) of embedded biofilm bacteria on the isolates susceptible to OTC (MBC < 10 μg/mL, 11/24). Moreover, these two combinations led to a reduction of the embedded biofilm bacteria higher than 3 log10 CFU/mL for 20–25% of the isolates. Further studies are now required to better understand the factors that cause the biofilm produced by specific isolates (20–25%) to be susceptible to the combinations.
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Affiliation(s)
- JingJing Liu
- Unité Antibiorésistance et Virulence Bactériennes, Université de Lyon - ANSES Laboratoire de Lyon, Lyon, France.,INTHERES, INRAE, ENVT, Université de Toulouse, Toulouse, France
| | - Jean-Yves Madec
- Unité Antibiorésistance et Virulence Bactériennes, Université de Lyon - ANSES Laboratoire de Lyon, Lyon, France
| | | | - Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, Université de Lyon - ANSES Laboratoire de Lyon, Lyon, France
| | - Aude A Ferran
- INTHERES, INRAE, ENVT, Université de Toulouse, Toulouse, France.
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Kranjec C, Morales Angeles D, Torrissen Mårli M, Fernández L, García P, Kjos M, Diep DB. Staphylococcal Biofilms: Challenges and Novel Therapeutic Perspectives. Antibiotics (Basel) 2021; 10:131. [PMID: 33573022 PMCID: PMC7911828 DOI: 10.3390/antibiotics10020131] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/21/2021] [Accepted: 01/27/2021] [Indexed: 12/14/2022] Open
Abstract
Staphylococci, like Staphylococcus aureus and S. epidermidis, are common colonizers of the human microbiota. While being harmless in many cases, many virulence factors result in them being opportunistic pathogens and one of the major causes of hospital-acquired infections worldwide. One of these virulence factors is the ability to form biofilms-three-dimensional communities of microorganisms embedded in an extracellular polymeric matrix (EPS). The EPS is composed of polysaccharides, proteins and extracellular DNA, and is finely regulated in response to environmental conditions. This structured environment protects the embedded bacteria from the human immune system and decreases their susceptibility to antimicrobials, making infections caused by staphylococci particularly difficult to treat. With the rise of antibiotic-resistant staphylococci, together with difficulty in removing biofilms, there is a great need for new treatment strategies. The purpose of this review is to provide an overview of our current knowledge of the stages of biofilm development and what difficulties may arise when trying to eradicate staphylococcal biofilms. Furthermore, we look into promising targets and therapeutic methods, including bacteriocins and phage-derived antibiofilm approaches.
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Affiliation(s)
- Christian Kranjec
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway; (C.K.); (D.M.A.); (M.T.M.)
| | - Danae Morales Angeles
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway; (C.K.); (D.M.A.); (M.T.M.)
| | - Marita Torrissen Mårli
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway; (C.K.); (D.M.A.); (M.T.M.)
| | - Lucía Fernández
- Department of Technology and Biotechnology of Dairy Products, Dairy Research Institute of Asturias (IPLA-CSIC), 33300 Villaviciosa, Spain; (L.F.); (P.G.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Pilar García
- Department of Technology and Biotechnology of Dairy Products, Dairy Research Institute of Asturias (IPLA-CSIC), 33300 Villaviciosa, Spain; (L.F.); (P.G.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway; (C.K.); (D.M.A.); (M.T.M.)
| | - Dzung B. Diep
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, 1432 Ås, Norway; (C.K.); (D.M.A.); (M.T.M.)
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Gor V, Ohniwa RL, Morikawa K. No Change, No Life? What We Know about Phase Variation in Staphylococcus aureus. Microorganisms 2021; 9:microorganisms9020244. [PMID: 33503998 PMCID: PMC7911514 DOI: 10.3390/microorganisms9020244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/13/2022] Open
Abstract
Phase variation (PV) is a well-known phenomenon of high-frequency reversible gene-expression switching. PV arises from genetic and epigenetic mechanisms and confers a range of benefits to bacteria, constituting both an innate immune strategy to infection from bacteriophages as well as an adaptation strategy within an infected host. PV has been well-characterized in numerous bacterial species; however, there is limited direct evidence of PV in the human opportunistic pathogen Staphylococcus aureus. This review provides an overview of the mechanisms that generate PV and focuses on earlier and recent findings of PV in S. aureus, with a brief look at the future of the field.
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Affiliation(s)
- Vishal Gor
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Correspondence: (V.G.); (K.M.)
| | - Ryosuke L. Ohniwa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
| | - Kazuya Morikawa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
- Correspondence: (V.G.); (K.M.)
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16
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Zhuang Y, Ren L, Zhang S, Wei X, Yang K, Dai K. Antibacterial effect of a copper-containing titanium alloy against implant-associated infection induced by methicillin-resistant Staphylococcus aureus. Acta Biomater 2021; 119:472-484. [PMID: 33091623 DOI: 10.1016/j.actbio.2020.10.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 01/04/2023]
Abstract
Implant-associated infection (IAI) induced by methicillin-resistant Staphylococcus aureus (MRSA) is a devastating complication in the orthopedic clinic. Traditional implant materials, such as Ti6Al4V, are vulnerable to microbial infection. In this study, we fabricated a copper (Cu)-containing titanium alloy (Ti6Al4V-Cu) for the prevention and treatment of MRSA-induced IAI. The material characteristics, antibacterial activity, and biocompatibility of Ti6Al4V-Cu were systematically investigated and compared with those of Ti6Al4V. Ti6Al4V-Cu provided stable and continuous Cu2+ release, at a rate of 0.106 mg/cm2/d. Its antibacterial performance against MRSA in vitro was confirmed by plate counting analysis, crystal violet staining, and scanning electron microscopic observations. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis demonstrated that Ti6Al4V-Cu suppressed biofilm formation, virulence, and antibiotic-resistance of MRSA. The in vivo anti-MRSA effect was investigated in a rat IAI model. Implants were contaminated with MRSA solution, implanted into the femur, and left for 6 weeks. Severe IAI developed in the Ti6Al4V group, with increased radiological score (9.6 ± 1.3) and high histological score (10.1 ± 1.9). However, no sign of infection was found in the Ti6Al4V-Cu group, as indicated by decreased radiological score (1.3 ± 0.4) and low histological score (2.3 ± 0.5). In addition, Ti6Al4V-Cu had favorable biocompatibility both in vitro and in vivo. In summary, Ti6Al4V-Cu is a promising implant material to protect against MRSA-induced IAI.
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The staphylococcal exopolysaccharide PIA - Biosynthesis and role in biofilm formation, colonization, and infection. Comput Struct Biotechnol J 2020. [PMID: 33240473 DOI: 10.1016/jcsbj202010027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Exopolysaccharide is a key part of the extracellular matrix that contributes to important mechanisms of bacterial pathogenicity, most notably biofilm formation and immune evasion. In the human pathogens Staphylococcus aureus and S. epidermidis, as well as in many other staphylococcal species, the only exopolysaccharide is polysaccharide intercellular adhesin (PIA), a cationic, partially deacetylated homopolymer of N-acetylglucosamine, whose biosynthetic machinery is encoded in the ica locus. PIA production is strongly dependent on environmental conditions and controlled by many regulatory systems. PIA contributes significantly to staphylococcal biofilm formation and immune evasion mechanisms, such as resistance to antimicrobial peptides and ingestion and killing by phagocytes, and presence of the ica genes is associated with infectivity. Due to its role in pathogenesis, PIA has raised considerable interest as a potential vaccine component or target.
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18
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Nguyen HTT, Nguyen TH, Otto M. The staphylococcal exopolysaccharide PIA - Biosynthesis and role in biofilm formation, colonization, and infection. Comput Struct Biotechnol J 2020; 18:3324-3334. [PMID: 33240473 PMCID: PMC7674160 DOI: 10.1016/j.csbj.2020.10.027] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/23/2020] [Accepted: 10/25/2020] [Indexed: 12/20/2022] Open
Abstract
PIA is a key extracellular matrix component in staphylococci and other bacteria. PIA is a cationic, partially deacetylated N-acetylglucosamine polymer. PIA has a major role in bacterial biofilms and biofilm-associated infection.
Exopolysaccharide is a key part of the extracellular matrix that contributes to important mechanisms of bacterial pathogenicity, most notably biofilm formation and immune evasion. In the human pathogens Staphylococcus aureus and S. epidermidis, as well as in many other staphylococcal species, the only exopolysaccharide is polysaccharide intercellular adhesin (PIA), a cationic, partially deacetylated homopolymer of N-acetylglucosamine, whose biosynthetic machinery is encoded in the ica locus. PIA production is strongly dependent on environmental conditions and controlled by many regulatory systems. PIA contributes significantly to staphylococcal biofilm formation and immune evasion mechanisms, such as resistance to antimicrobial peptides and ingestion and killing by phagocytes, and presence of the ica genes is associated with infectivity. Due to its role in pathogenesis, PIA has raised considerable interest as a potential vaccine component or target.
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Affiliation(s)
- Hoai T T Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda 20814, MD, USA.,School of Biotechnology, International University, Vietnam National University of Ho Chi Minh City, Khu Pho 6, Thu Duc, Ho Chi Minh City, Viet Nam
| | - Thuan H Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda 20814, MD, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda 20814, MD, USA
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19
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The Protective Effect of Staphylococcus epidermidis Biofilm Matrix against Phage Predation. Viruses 2020; 12:v12101076. [PMID: 32992766 PMCID: PMC7601396 DOI: 10.3390/v12101076] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/13/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus epidermidis is a major causative agent of nosocomial infections, mainly associated with the use of indwelling devices, on which this bacterium forms structures known as biofilms. Due to biofilms’ high tolerance to antibiotics, virulent bacteriophages were previously tested as novel therapeutic agents. However, several staphylococcal bacteriophages were shown to be inefficient against biofilms. In this study, the previously characterized S. epidermidis-specific Sepunavirus phiIBB-SEP1 (SEP1), which has a broad spectrum and high activity against planktonic cells, was evaluated concerning its efficacy against S. epidermidis biofilms. The in vitro biofilm killing assays demonstrated a reduced activity of the phage. To understand the underlying factors impairing SEP1 inefficacy against biofilms, this phage was tested against distinct planktonic and biofilm-derived bacterial populations. Interestingly, SEP1 was able to lyse planktonic cells in different physiological states, suggesting that the inefficacy for biofilm control resulted from the biofilm 3D structure and the protective effect of the matrix. To assess the impact of the biofilm architecture on phage predation, SEP1 was tested in disrupted biofilms resulting in a 2 orders-of-magnitude reduction in the number of viable cells after 6 h of infection. The interaction between SEP1 and the biofilm matrix was further assessed by the addition of matrix to phage particles. Results showed that the matrix did not inactivate phages nor affected phage adsorption. Moreover, confocal laser scanning microscopy data demonstrated that phage infected cells were less predominant in the biofilm regions where the matrix was more abundant. Our results provide compelling evidence indicating that the biofilm matrix can work as a barrier, allowing the bacteria to be hindered from phage infection.
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Effect of manuka honey on biofilm-associated genes expression during methicillin-resistant Staphylococcus aureus biofilm formation. Sci Rep 2020; 10:13552. [PMID: 32782291 PMCID: PMC7419495 DOI: 10.1038/s41598-020-70666-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/31/2020] [Indexed: 12/24/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) are among the most important biofilm-forming pathogens responsible for hard-to-treat infections. Looking for alternatives to antibiotics that prevent biofilm formation, we investigated the effects of manuka honey on the transcriptional profile of genes essential for staphylococcal biofilm formation using qRT-PCR. mRNA from two hospital MRSA strains (strong and weak biofilm producer) were isolated after 4, 8, 12 and 24 h from cells grown in biofilm. Manuka honey at 1/2 minimum biofilm inhibition concentration (MBIC) significantly reduced MRSA cell viability in biofilm. Manuka honey downregulated the genes encoding laminin- (eno), elastin- (ebps) and fibrinogen binding protein (fib), and icaA and icaD involved in biosynthesis of polysaccharide intercellular adhesin in both weakly and strongly adhering strain compared to the control (untreated biofilm). Expression levels of cna (collagen binding protein) and map/eap (extracellular adherence protein—Eap) were reduced in weakly adhering strain. The lowest expression of investigated genes was observed after 12 h of manuka honey treatment at 1/2 MBIC. This study showed that the previously unknown mechanism of manuka honey action involved inhibition of S. aureus adhesion due to reduction in expression of crucial genes associated with staphylococcal biofilm.
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21
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Complete Structure of the Enterococcal Polysaccharide Antigen (EPA) of Vancomycin-Resistant Enterococcus faecalis V583 Reveals that EPA Decorations Are Teichoic Acids Covalently Linked to a Rhamnopolysaccharide Backbone. mBio 2020; 11:mBio.00277-20. [PMID: 32345640 PMCID: PMC7188991 DOI: 10.1128/mbio.00277-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Enterococci are opportunistic pathogens responsible for hospital- and community-acquired infections. All enterococci produce a surface polysaccharide called EPA (enterococcal polysaccharide antigen) required for biofilm formation, antibiotic resistance, and pathogenesis. Despite the critical role of EPA in cell growth and division and as a major virulence factor, no information is available on its structure. Here, we report the complete structure of the EPA polymer produced by the model strain E. faecalis V583. We describe the structure of the EPA backbone, made of a rhamnan hexasaccharide substituted by Glc and GlcNAc residues, and show that teichoic acids are covalently bound to this rhamnan chain, forming the so-called “EPA decorations” essential for host colonization and pathogenesis. This report represents a key step in efforts to identify the structural properties of EPA that are essential for its biological activity and to identify novel targets to develop preventive and therapeutic approaches against enterococci. All enterococci produce a complex polysaccharide called the enterococcal polysaccharide antigen (EPA). This polymer is required for normal cell growth and division and for resistance to cephalosporins and plays a critical role in host-pathogen interaction. The EPA contributes to host colonization and is essential for virulence, conferring resistance to phagocytosis during the infection. Recent studies revealed that the “decorations” of the EPA polymer, encoded by genetic loci that are variable between isolates, underpin the biological activity of this surface polysaccharide. In this work, we investigated the structure of the EPA polymer produced by the high-risk enterococcal clonal complex Enterococcus faecalis V583. We analyzed purified EPA from the wild-type strain and a mutant lacking decorations and elucidated the structure of the EPA backbone and decorations. We showed that the rhamnan backbone of EPA is composed of a hexasaccharide repeat unit of C2- and C3-linked rhamnan chains, partially substituted in the C3 position by α-glucose (α-Glc) and in the C2 position by β-N-acetylglucosamine (β-GlcNAc). The so-called “EPA decorations” consist of phosphopolysaccharide chains corresponding to teichoic acids covalently bound to the rhamnan backbone. The elucidation of the complete EPA structure allowed us to propose a biosynthetic pathway, a first essential step toward the design of antimicrobials targeting the synthesis of this virulence factor.
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Kot B, Sytykiewicz H, Sprawka I, Witeska M. Effect of trans-Cinnamaldehyde on Methicillin-Resistant Staphylococcus aureus Biofilm Formation: Metabolic Activity Assessment and Analysis of the Biofilm-Associated Genes Expression. Int J Mol Sci 2019; 21:ijms21010102. [PMID: 31877837 PMCID: PMC6981724 DOI: 10.3390/ijms21010102] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/19/2019] [Accepted: 12/19/2019] [Indexed: 01/21/2023] Open
Abstract
The effects of trans-cinnamaldehyde (TC) on transcriptional profiles of biofilm-associated genes and the metabolic activity of two methicillin-resistant Staphylococcus aureus (MRSA) strains showing a different degree of adherence to polystyrene, were evaluated. Metabolic activity of S. aureus in biofilm was significantly decreased in the presence of TC at 1/2 minimum biofilm inhibition concentration (MBIC). Expression levels of the genes encoding laminin binding protein (eno), elastin binding protein (ebps) and fibrinogen binding protein (fib) in the presence of TC at 1/2 MBIC were lower than in untreated biofilm in both the weakly and strongly adhering strain. The highest decrease of expression level was observed in case of fib in the strongly adhering strain, in which the amount of fib transcript was 10-fold lower compared to biofilm without TC. In the presence of TC at 1/2 MBIC after 3, 6, 8 and 12 h, the expression level of icaA and icaD, that are involved in the biosynthesis of polysaccharide intercellular adhesin, was above half lower in the weakly adhering strain compared to biofilm without TC. In the strongly adhering strain the highest decrease in expression of these genes was observed after 3 and 6 h. This study showed that TC is a promising anti-biofilm agent for use in MRSA biofilm-related infections.
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Abstract
Staphylococci have been isolated from various sites of the body of healthy sheep, as well as from many infections of those animals, the main one being mastitis. The objective of this review is to appraise the importance and significance of staphylococci in causing mastitis in ewes. The review includes a brief classification and taxonomy of staphylococci and describes the procedures for their isolation and identification, as well as their virulence determinants and the mechanisms of resistance to antibacterial agents. Various staphylococcal species have been implicated in staphylococcal mastitis and the characteristics of isolates are discussed with regards to potential virulence factors. Staphylococcal mastitis is explicitly described, with reference to sources of infection, the course of the disease and the relevant control measures. Finally, the potential significance of staphylococci present in ewes' milk for public health is discussed briefly.
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25
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Effect of Cryptotanshinone on Staphylococcus epidermidis Biofilm Formation Under In Vitro Conditions. Jundishapur J Microbiol 2019. [DOI: 10.5812/jjm.83922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Raafat D, Otto M, Reppschläger K, Iqbal J, Holtfreter S. Fighting Staphylococcus aureus Biofilms with Monoclonal Antibodies. Trends Microbiol 2019; 27:303-322. [PMID: 30665698 DOI: 10.1016/j.tim.2018.12.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/10/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus (S. aureus) is a notorious pathogen and one of the most frequent causes of biofilm-related infections. The treatment of S. aureus biofilms is hampered by the ability of the biofilm structure to shield bacteria from antibiotics as well as the host's immune system. Therefore, new preventive and/or therapeutic interventions, including the use of antibody-based approaches, are urgently required. In this review, we describe the mechanisms by which anti-S. aureus antibodies can help in combating biofilms, including an up-to-date overview of monoclonal antibodies currently in clinical trials. Moreover, we highlight ongoing efforts in passive vaccination against S. aureus biofilm infections, with special emphasis on promising targets, and finally indicate the direction into which future research could be heading.
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Affiliation(s)
- Dina Raafat
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Egypt; Current affiliation: Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD, USA
| | - Kevin Reppschläger
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Jawad Iqbal
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Silva Holtfreter
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany.
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Ostapska H, Howell PL, Sheppard DC. Deacetylated microbial biofilm exopolysaccharides: It pays to be positive. PLoS Pathog 2018; 14:e1007411. [PMID: 30589915 PMCID: PMC6307706 DOI: 10.1371/journal.ppat.1007411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Hanna Ostapska
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- * E-mail: (PLH); (DCS)
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- * E-mail: (PLH); (DCS)
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Biofilm Formation by Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains from Hospitalized Patients in Poland. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4657396. [PMID: 30687745 PMCID: PMC6327255 DOI: 10.1155/2018/4657396] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 11/20/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
Biofilm-mediated infections in the hospital environment have a significant negative impact on patient health. This study aimed to investigate biofilm production in vitro and the presence of icaABCD genes in methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains isolated from hospitalized patients. MRSA (73) and MSSA (57) strains were evaluated for biofilm production by the microtiter plate method. The presence of ica operon was investigated by PCR. Out of 130 strains, 99.2% were biofilm producers. Strong biofilms were formed by 39.7% of MRSA and 36.8% of MSSA strains. The highest percentage of strong biofilm producers was found among the strains isolated from sputum and tracheostomy tube (66.7%), nose and catheter (50%), throat (44.4%), and bronchoalveolar washings (43.8%). The strains isolated from bronchoalveolar washings produced significantly more biofilm than strains isolated from wound and anus. The ability of biofilm forming by fecal strains was significantly lower compared to strains from other materials. MRSA strains had significantly higher ability of biofilm formation than MSSA strains (P = 0.000247). The presence of ica operon in MRSA was detected in all strains. Comparison of strong biofilm biomass of the strains with icaABCD, icaABD, and icaAD revealed that strains with icaABCD and icaABD produced highly significantly more biofilm than strains with icaAD. Biofilm forming by both MRSA and MSSA strains indicates high ability of theses strains to persist in hospital environment which increases the risk of disease development in hospitalized patients.
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Kot B, Sytykiewicz H, Sprawka I. Expression of the Biofilm-Associated Genes in Methicillin-Resistant Staphylococcus aureus in Biofilm and Planktonic Conditions. Int J Mol Sci 2018; 19:ijms19113487. [PMID: 30404183 PMCID: PMC6274806 DOI: 10.3390/ijms19113487] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 10/30/2018] [Accepted: 11/02/2018] [Indexed: 11/16/2022] Open
Abstract
The role of genes that are essential for development of Staphylococcus aureus biofilm during infection is not fully known. mRNA from two methicillin-resistant S. aureus strains that formed weak and strong biofilm on polystyrene plates were isolated at five time points from cells grown in biofilm and planktonic culture. Quantitative real-time PCR analysis showed that the expression levels of investigated genes under biofilm conditions were significantly higher than under planktonic conditions. The expression levels of the gene encoding elastin binding protein (ebps) and laminin binding protein (eno) were significantly increased in biofilm at 3 h, both in strongly and weakly adhering strain. The peak expression of fib gene encoding fibrinogen binding protein was found at 6 and 8 h in the case of strongly and weakly adhering strain, respectively. The expression of icaA and icaD genes in both strains was significantly higher under biofilm conditions when comparing to planktonic cells during 12 h. The expression level of the genes encoding binding proteins and the glucosamine polymer polysaccharide intercellular adhesin (PIA) slowly decreased after 24 h. Finally, we found that the expression levels of genes encoding binding factors in weakly adhering strain were significantly lower than in strongly adhering strain.
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Affiliation(s)
- Barbara Kot
- Department of Microbiology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
| | - Hubert Sytykiewicz
- Department of Biochemistry and Molecular Biology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
| | - Iwona Sprawka
- Department of Biochemistry and Molecular Biology, Faculty of Natural Sciences, Siedlce University of Natural Sciences and Humanities, 14 Bolesława Prusa Str., 08-110 Siedlce, Poland.
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Vasileiou N, Chatzopoulos D, Gougoulis D, Sarrou S, Katsafadou A, Spyrou V, Mavrogianni V, Petinaki E, Fthenakis G. Slime-producing staphylococci as causal agents of subclinical mastitis in sheep. Vet Microbiol 2018; 224:93-99. [DOI: 10.1016/j.vetmic.2018.08.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/22/2018] [Accepted: 08/22/2018] [Indexed: 11/28/2022]
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Cywes-Bentley C, Rocha JN, Bordin AI, Vinacur M, Rehman S, Zaidi TS, Meyer M, Anthony S, Lambert M, Vlock DR, Giguère S, Cohen ND, Pier GB. Antibody to Poly-N-acetyl glucosamine provides protection against intracellular pathogens: Mechanism of action and validation in horse foals challenged with Rhodococcus equi. PLoS Pathog 2018; 14:e1007160. [PMID: 30024986 PMCID: PMC6053243 DOI: 10.1371/journal.ppat.1007160] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022] Open
Abstract
Immune correlates of protection against intracellular bacterial pathogens are largely thought to be cell-mediated, although a reasonable amount of data supports a role for antibody-mediated protection. To define a role for antibody-mediated immunity against an intracellular pathogen, Rhodococcus equi, that causes granulomatous pneumonia in horse foals, we devised and tested an experimental system relying solely on antibody-mediated protection against this host-specific etiologic agent. Immunity was induced by vaccinating pregnant mares 6 and 3 weeks prior to predicted parturition with a conjugate vaccine targeting the highly conserved microbial surface polysaccharide, poly-N-acetyl glucosamine (PNAG). We ascertained antibody was transferred to foals via colostrum, the only means for foals to acquire maternal antibody. Horses lack transplacental antibody transfer. Next, a randomized, controlled, blinded challenge was conducted by inoculating at ~4 weeks of age ~106 cfu of R. equi via intrabronchial challenge. Eleven of 12 (91%) foals born to immune mares did not develop clinical R. equi pneumonia, whereas 6 of 7 (86%) foals born to unvaccinated controls developed pneumonia (P = 0.0017). In a confirmatory passive immunization study, infusion of PNAG-hyperimmune plasma protected 100% of 5 foals against R. equi pneumonia whereas all 4 recipients of normal horse plasma developed clinical disease (P = 0.0079). Antibodies to PNAG mediated killing of extracellular and intracellular R. equi and other intracellular pathogens. Killing of intracellular organisms depended on antibody recognition of surface expression of PNAG on infected cells, along with complement deposition and PMN-assisted lysis of infected macrophages. Peripheral blood mononuclear cells from immune and protected foals released higher levels of interferon-γ in response to PNAG compared to controls, indicating vaccination also induced an antibody-dependent cellular release of this critical immune cytokine. Overall, antibody-mediated opsonic killing and interferon-γ release in response to PNAG may protect against diseases caused by intracellular bacterial pathogens. Development of effective vaccines for diseases such as tuberculosis, brucellosis and others caused by intracellular pathogens has proved challenging, as data exist supporting both antibody and cellular immune effectors as mediators of protection. To address this problem against an important, and representative, equine intracellular pathogen, we chose to test a vaccine candidate for the ability to protect horse foals challenged at 4 weeks of age with Rhodococcus equi. To make these foals immune, their pregnant mares were immunized with a vaccine targeting the conserved surface antigen found on many microbes, termed PNAG. Antibody in the pregnant mares was transferred to their foals and, after the foals were challenged, 91% of those born to vaccinated mares were protected against R. equi pneumonia. Meanwhile, 86% of the non-vaccinated controls developed pneumonia. We also showed antibody to PNAG could kill various bacteria that produce this antigen when residing inside of human macrophage cells, a new mechanism for antibody-mediated immunity to intracellular bacteria. These results support the development of PNAG as a vaccine for intracellular bacterial pathogens.
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Affiliation(s)
- Colette Cywes-Bentley
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Joana N. Rocha
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Angela I. Bordin
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Mariana Vinacur
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Safia Rehman
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Tanweer S. Zaidi
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Mark Meyer
- Mg Biologics, Ames, IA, United States of America
| | | | | | | | - Steeve Giguère
- College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Noah D. Cohen
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
- * E-mail: (NDC); (GBP)
| | - Gerald B. Pier
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
- * E-mail: (NDC); (GBP)
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Immunization with outer membrane vesicles displaying conserved surface polysaccharide antigen elicits broadly antimicrobial antibodies. Proc Natl Acad Sci U S A 2018; 115:E3106-E3115. [PMID: 29555731 DOI: 10.1073/pnas.1718341115] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Many microbial pathogens produce a β-(1→6)-linked poly-N-acetyl-d-glucosamine (PNAG) surface capsule, including bacterial, fungal, and protozoan cells. Broadly protective immune responses to this single conserved polysaccharide antigen in animals are possible but only when a deacetylated poly-N-acetyl-d-glucosamine (dPNAG; <30% acetate) glycoform is administered as a conjugate to a carrier protein. Unfortunately, conventional methods for natural extraction or chemical synthesis of dPNAG and its subsequent conjugation to protein carriers can be technically demanding and expensive. Here, we describe an alternative strategy for creating broadly protective vaccine candidates that involved coordinating recombinant poly-N-acetyl-d-glucosamine (rPNAG) biosynthesis with outer membrane vesicle (OMV) formation in laboratory strains of Escherichia coli The glycosylated outer membrane vesicles (glycOMVs) released by these engineered bacteria were decorated with the PNAG glycopolymer and induced high titers of PNAG-specific IgG antibodies after immunization in mice. When a Staphylococcus aureus enzyme responsible for PNAG deacetylation was additionally expressed in these cells, glycOMVs were generated that elicited antibodies to both highly acetylated PNAG (∼95-100% acetate) and a chemically deacetylated dPNAG derivative (∼15% acetate). These antibodies mediated efficient in vitro killing of two distinct PNAG-positive bacterial species, namely S. aureus and Francisella tularensis subsp. holarctica, and mice immunized with PNAG-containing glycOMVs developed protective immunity against these unrelated pathogens. Collectively, our results reveal the potential of glycOMVs for targeting this conserved polysaccharide antigen and engendering protective immunity against the broad range of pathogens that produce surface PNAG.
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Thomsen IP, Liu GY. Targeting fundamental pathways to disrupt Staphylococcus aureus survival: clinical implications of recent discoveries. JCI Insight 2018. [PMID: 29515041 DOI: 10.1172/jci.insight.98216] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The emergence of community-associated methicillin-resistant Staphylococcus aureus during the past decade along with an impending shortage of effective antistaphylococcal antibiotics have fueled impressive advances in our understanding of how S. aureus overcomes the host environment to establish infection. Backed by recent technologic advances, studies have uncovered elaborate metabolic, nutritional, and virulence strategies deployed by S. aureus to survive the restrictive and hostile environment imposed by the host, leading to a plethora of promising antimicrobial approaches that have potential to remedy the antibiotic resistance crisis. In this Review, we highlight some of the critical and recently elucidated bacterial strategies that are potentially amenable to intervention, discuss their relevance to human diseases, and address the translational challenges posed by current animal models.
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Affiliation(s)
- Isaac P Thomsen
- Department of Pediatrics, Division of Pediatric Infectious Diseases, and Vanderbilt Vaccine Research Program, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George Y Liu
- Division of Pediatric Infectious Diseases and Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
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The Photodynamic Effect of Tetra-Substituted N-Methyl-Pyridyl-Porphine Combined with the Action of Vancomycin or Host Defense Mechanisms Disrupts Staphylococcus Epidermidis Biofilms. Int J Artif Organs 2018; 32:574-83. [DOI: 10.1177/039139880903200906] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The skin commensal and opportunistic pathogen Staphylococcus epidermidis is an important cause of nosocomial infections. Virulence is attributable to formation of biofilm, which provides a microenvironment that protects the bacterium from attack by the host immune system and by chemotherapy. In this study we extended to S. epidermidis strategies previously aimed at treatment of S. aureus bio films using photodynamic treatment (PDT) combined with chemotherapy or phagocytosis. A significant reduction in bacterial survival was observed when structurally distinct biofilms were exposed to the cationic porphyrin, tetra-substituted N-methyl-pyridyl-porphine (TMP), and simultaneously to visible light. Of note, the extent of biofilm clearance depended on its maturation stage: developing, young biofilms, were more sensitive towards PDT than mature biofilms. Furthermore, PDT-treated biofilms exposed to vancomycin or subjected to phagocytic action of whole blood were almost completely eradicated. The data we obtained establish that PDT combined with antibiotics or host defenses may also be a useful approach for the inactivation of S. epidermidis biofilms.
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Schumann B, Hahm HS, Parameswarappa SG, Reppe K, Wahlbrink A, Govindan S, Kaplonek P, Pirofski LA, Witzenrath M, Anish C, Pereira CL, Seeberger PH. A semisynthetic Streptococcus pneumoniae serotype 8 glycoconjugate vaccine. Sci Transl Med 2017; 9:9/380/eaaf5347. [PMID: 28275152 DOI: 10.1126/scitranslmed.aaf5347] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/19/2016] [Accepted: 02/06/2017] [Indexed: 01/09/2023]
Abstract
Glycoconjugate vaccines based on capsular polysaccharides (CPSs) of pathogenic bacteria such as Streptococcus pneumoniae successfully protect from disease but suffer from incomplete coverage, are troublesome to manufacture from isolated CPSs, and lack efficacy against certain serotypes. Defined, synthetic oligosaccharides are an attractive alternative to isolated CPSs but require the identification of immunogenic and protective oligosaccharide antigens. We describe a medicinal chemistry strategy based on a combination of automated glycan assembly (AGA), glycan microarray-based monoclonal antibody (mAb) reverse engineering, and immunological evaluation in vivo to uncover a protective glycan epitope (glycotope) for S. pneumoniae serotype 8 (ST8). All four tetrasaccharide frameshifts of ST8 CPS were prepared by AGA and used in glycan microarray experiments to identify the glycotopes recognized by antibodies against ST8. One tetrasaccharide frameshift that was preferentially recognized by a protective, CPS-directed mAb was conjugated to the carrier protein CRM197. Immunization of mice with this semisynthetic glycoconjugate followed by generation and characterization of a protective mAb identified protective and nonprotective glycotopes. Immunization of rabbits with semisynthetic ST8 glycoconjugates containing protective glycotopes induced an antibacterial immune response. Coformulation of ST8 glycoconjugates with the marketed 13-valent glycoconjugate vaccine Prevnar 13 yielded a potent 14-valent S. pneumoniae vaccine. Our strategy presents a facile approach to develop efficient semisynthetic glycoconjugate vaccines.
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Affiliation(s)
- Benjamin Schumann
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany.,Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Heung Sik Hahm
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany.,Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | | | - Katrin Reppe
- Division of Pulmonary Inflammation, Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Annette Wahlbrink
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany
| | - Subramanian Govindan
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany
| | - Paulina Kaplonek
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany.,Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Liise-Anne Pirofski
- Division of Infectious Diseases, Department of Medicine, Montefiore Medical Center and Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Martin Witzenrath
- Division of Pulmonary Inflammation, Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Chakkumkal Anish
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany
| | - Claney L Pereira
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany.
| | - Peter H Seeberger
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany. .,Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
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Shanmugam M, Oyeniyi AO, Parthiban C, Gujjarlapudi SK, Pier GB, Ramasubbu N. Role of de-N-acetylase PgaB from Aggregatibacter actinomycetemcomitans in exopolysaccharide export in biofilm mode of growth. Mol Oral Microbiol 2017; 32:500-510. [PMID: 28548373 DOI: 10.1111/omi.12188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2017] [Indexed: 11/29/2022]
Abstract
Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, is the causative agent of localized aggressive periodontitis. Attachment to a biotic surface is a critical first step in the A. actinomycetemcomitans infection process for which exopolysaccharides have been shown to be essential. In addition, the pga operon, containing genes encoding for biosynthetic proteins for poly-N-acetyl glucosamine (PNAG), plays a key role in A. actinomycetemcomitans virulence, as a mutant strain lacking the pga operon induces significantly less bone resorption. Among the genes in the pga operon, pgaB codes for a de-N-acetylase that is responsible for the deacetylation of the PNAG exopolysaccharide. Here we report the role of PgaB in regulation of virulence genes using a markerless, scarless deletion mutant targeting the coding region of the N-terminal catalytic domain of PgaB. The results demonstrate that the N-terminal, catalytic domain of PgaB is crucial for exopolysaccharide export.
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Affiliation(s)
- M Shanmugam
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - A O Oyeniyi
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - C Parthiban
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - S K Gujjarlapudi
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - G B Pier
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - N Ramasubbu
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
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37
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Zhao G, Zaidi TS, Bozkurt-Guzel C, Zaidi TH, Lederer JA, Priebe GP, Pier GB. Efficacy of Antibody to PNAG Against Keratitis Caused by Fungal Pathogens. Invest Ophthalmol Vis Sci 2017; 57:6797-6804. [PMID: 28002842 PMCID: PMC5215555 DOI: 10.1167/iovs.16-20358] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Purpose Developing immunotherapies for fungal eye infections is a high priority. We analyzed fungal pathogens for expression of the surface polysaccharide, poly-N-acetyl glucosamine (PNAG), and used a mouse model of ocular keratitis caused by Aspergillus flavus, A. fumigatus, or Fusarium solani to determine if PNAG was an immunotherapy target and requirements for ancillary cellular and molecular immune effectors. Methods Enzyme-linked immunosorbent assay (ELISA) or immunofluorescence was used to detect PNAG on fungal cells. Keratitis was induced by scratching corneas of C57BL/6, IL-17R KO, RAG-1 KO, or IL-22 KO mice followed by inoculation with fungal pathogens. Goat antibodies to PNAG, a PNAG-specific human IgG1 monoclonal antibody, or control antibodies were injected either prophylactically plus therapeutically or therapeutically only, and corneal pathology and fungal levels determined in infected eyes at 24 or 48 hours after infection. Results All tested fungal species produced PNAG. Prophylactic or therapeutic treatment by intraperitoneal (IP) injection of antibody to PNAG combined with post-infection topical application of antibody, the latter also used for A. fumigatus, led to reduced fungal levels, corneal pathology, and cytokine expression. Topical administration only of the PNAG monoclonal antibodies (MAb) reduced fungal loads and corneal pathology. There was no antibody protection in IL-17R KO, RAG-1 KO, or IL-22 KO mice. Conclusions Poly-N-acetyl glucosamine is produced by clinically important fungal ocular pathogens. Antibody to PNAG demonstrated protection against Aspergillus and Fusarium keratitis, requiring T cells producing IL-17 and IL-22. These findings indicate the potential to prevent or treat fungal infections by vaccines and immunotherapeutics to PNAG.
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Affiliation(s)
- Ge Zhao
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Tanweer S Zaidi
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Cagla Bozkurt-Guzel
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Tauqeer H Zaidi
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - James A Lederer
- Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Gregory P Priebe
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States 3Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
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Søe NH, Jensen NV, Jensen AL, Koch J, Poulsen SS, Pier GB, Johansen HK. Active and Passive Immunization Against Staphylococcus aureus Periprosthetic Osteomyelitis in Rats. ACTA ACUST UNITED AC 2017; 31:45-50. [PMID: 28064219 DOI: 10.21873/invivo.11023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/24/2016] [Accepted: 12/08/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND/AIM Staphylococcus aureus infection associated with orthopedic implants cannot always be controlled. We used a knee prosthesis model with implant-related osteomyelitis in rats to explore induction of an effective immune response with active and passive immunization. MATERIALS AND METHODS Fifty-two Sprague-Dawley rats were divided into active (N=28) and passive immunization groups (N=24). A bacterial inoculum of 103 S. aureus MN8 was injected into the tibia and the femur marrow before insertion of a non-constrained knee prosthesis in each rat. The active-immunization group received a synthetic oligosaccharide of polysaccharide poly-N-acetylglucosamine (PNAG), 9G1cNH2 and the passive-immunization group received immunization with immunoglobulin from rabbits infected with S. aureus. RESULTS/CONCLUSION Active immunization against PNAG significantly reduced the consequences of osteomyelitis infection from PNAG-producing intercellular adhesion (ica+) but not ica- S. aureus. Passive immunization resulted in better clinical assessments in animals challenged with either ica+ or ica- S. aureus, suggesting a lack of specificity in this antiserum.
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Affiliation(s)
- Niels H Søe
- Hand Section, Department of Orthopaedics, Herlev and Gentofte University Hospital, Hellerup, Denmark
| | - Nina Vendel Jensen
- Department of Anaesthesiology, Intensive Care and Operations, Herlev and Gentofte University Hospital, Hellerup, Denmark
| | - Asger Lundorff Jensen
- Biochemical Department, Faculty of Life Science, University of Copenhagen, Copenhagen, Denmark
| | - Janne Koch
- Department of Experimental Medicine, Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark
| | - Steen Seier Poulsen
- Biomedical Department, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, U.S.A
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark.,The Novo Nordisk Foundation, Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
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Wang Y, Yi L, Wang Y, Wang Y, Cai Y, Zhao W, Ding C. Isolation, phylogenetic group, drug resistance, biofilm formation, and adherence genes of Escherichia coli from poultry in central China. Poult Sci 2016; 95:2895-2901. [PMID: 27597777 DOI: 10.3382/ps/pew252] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/30/2015] [Accepted: 06/16/2016] [Indexed: 12/22/2022] Open
Abstract
The isolation and identification, genetic typing, antibiotic sensitivity, and biofilm formation of avian Escherichia coli in central China was studied. A total of 256 isolates of E. coli were obtained, and classified into groups: A (50.78%, 130/256), B1 (11.72%, 30/256), B2 (17.58%, 45/256), and D (19.92%, 51/256). Drug susceptibility testing revealed that the strains showed a high drug resistance rate against penicillin, aztreonam, rifampicin, kanamycin, clindamycin, and gentamicin, with 92.19% of strains exhibiting multi-drug resistance. A biofilm assay revealed that 81.64% of isolates could form biofilms. Of the total isolates, 25.39% of isolates showed strong biofilm-formation ability, 31.25% showed moderate biofilm-formation ability, 28.90% showed weak biofilm-formation ability, and 18.36% were unable to form biofilms. Most adhesion-associated genes were distributed among 5 or 8 genes in strong biofilm-forming ability isolates. However, adhesion-associated genes distributed among 1 or 4 genes were found in weak biofilm-forming ability isolates and non-ability isolates. The results showed a high drug resistance rate and biofilm formation ability in E.coli strains isolated from poultry. The isolates which have strong biofilm-forming ability were mostly belong to pathogenic E. coli (B2, D). Furthermore, it was the first report to demonstrate a positive correlation between adhesion-encoding genes and biofilms phenotype.
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Affiliation(s)
- Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471003, China .,Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200032,China.,Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, 33612, USA
| | - Li Yi
- College of Life Science, Luoyang Normal University, Luoyang, 471022, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471003, China
| | - Yuanguo Wang
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, 33612, USA
| | - Ying Cai
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, 33612, USA
| | - Wenpeng Zhao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471003, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200032,China
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Skurnik D, Cywes-Bentley C, Pier GB. The exceptionally broad-based potential of active and passive vaccination targeting the conserved microbial surface polysaccharide PNAG. Expert Rev Vaccines 2016; 15:1041-53. [PMID: 26918288 PMCID: PMC4985264 DOI: 10.1586/14760584.2016.1159135] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/24/2016] [Indexed: 11/08/2022]
Abstract
A challenging component of vaccine development is the large serologic diversity of protective antigens. Remarkably, there is a conserved surface/capsular polysaccharide, one of the most effective vaccine targets, expressed by a large number of bacterial, fungal and eukaryotic pathogens: poly-N-acetyl glucosamine (PNAG). Natural antibodies to PNAG are poorly effective at mediating in vitro microbial killing or in vivo protection. Removing most of the acetate substituents to produce a deacetylated glycoform, or using synthetic oligosaccharides of poly-β-1-6-linked glucosamine conjugated to carrier proteins, results in vaccines that elicit high levels of broad-based immunity. A fully human monoclonal antibody is highly active in laboratory and preclinical studies and has been successfully tested in a phase-I setting. Both the synthetic oligosaccharide conjugate vaccine and MAb will be further tested in humans starting in 2016; but, even if effective against only a fraction of the PNAG-producing pathogens, a major advance in vaccine-preventable diseases will occur.
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Affiliation(s)
- David Skurnik
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, 181 Longwood Ave., Boston, MA 02115, Phone: 617-525-2269; FAX: 617-525-2510
| | - Colette Cywes-Bentley
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, 181 Longwood Ave., Boston, MA 02115, Phone: 617-525-2269; FAX: 617-525-2510
| | - Gerald B. Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, 181 Longwood Ave., Boston, MA 02115, Phone: 617-525-2269; FAX: 617-525-2510
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Guillard T, Pons S, Roux D, Pier GB, Skurnik D. Antibiotic resistance and virulence: Understanding the link and its consequences for prophylaxis and therapy. Bioessays 2016; 38:682-93. [PMID: 27248008 DOI: 10.1002/bies.201500180] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
"Antibiotic resistance is usually associated with a fitness cost" is frequently accepted as common knowledge in the field of infectious diseases. However, with the advances in high-throughput DNA sequencing that allows for a comprehensive analysis of bacterial pathogenesis at the genome scale, including antibiotic resistance genes, it appears that this paradigm might not be as solid as previously thought. Recent studies indicate that antibiotic resistance is able to enhance bacterial fitness in vivo with a concomitant increase in virulence during infections. As a consequence, strategies to minimize antibiotic resistance turn out to be not as simple as initially believed. Indeed, decreased antibiotic use may not be sufficient to let susceptible strains outcompete the resistant ones. Here, we put in perspective these findings and review alternative approaches, such as preventive and therapeutic anti-bacterial immunotherapies that have the potential to by-pass the classic antibiotics.
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Affiliation(s)
- Thomas Guillard
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Laboratoire de Bactériologie-Virologie-Hygiène hospitalière, Hôpital Robert Debré - CHU de Reims, UFR de Médecine, Université de Reims Champagne-Ardenne, Reims, France
| | - Stéphanie Pons
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Damien Roux
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,INSERM, IAME, UMR 1137, Paris, France.,Univ Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, Paris, France.,AP-HP, Hôpital Louis Mourier, Service de Réanimation Médico-Chirurgicale, Colombes, France
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - David Skurnik
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Abstract
During the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. Depending on the nature of these interactions, attachment can be transient or permanent. To achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. This article reviews the recent advances in our understanding of the secretion, assembly, and regulation of the bacterial adhesins during biofilm formation, with a particular emphasis on the fimbrial, nonfimbrial, and discrete polysaccharide adhesins in Gram-negative bacteria.
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Abstract
The mold Aspergillus fumigatus causes invasive infection in immunocompromised patients. Recently, galactosaminogalactan (GAG), an exopolysaccharide composed of galactose and N-acetylgalactosamine (GalNAc), was identified as a virulence factor required for biofilm formation. The molecular mechanisms underlying GAG biosynthesis and GAG-mediated biofilm formation were unknown. We identified a cluster of five coregulated genes that were dysregulated in GAG-deficient mutants and whose gene products share functional similarity with proteins that mediate the synthesis of the bacterial biofilm exopolysaccharide poly-(β1-6)-N-acetyl-d-glucosamine (PNAG). Bioinformatic analyses suggested that the GAG cluster gene agd3 encodes a protein containing a deacetylase domain. Because deacetylation of N-acetylglucosamine residues is critical for the function of PNAG, we investigated the role of GAG deacetylation in fungal biofilm formation. Agd3 was found to mediate deacetylation of GalNAc residues within GAG and render the polysaccharide polycationic. As with PNAG, deacetylation is required for the adherence of GAG to hyphae and for biofilm formation. Growth of the Δagd3 mutant in the presence of culture supernatants of the GAG-deficient Δuge3 mutant rescued the biofilm defect of the Δagd3 mutant and restored the adhesive properties of GAG, suggesting that deacetylation is an extracellular process. The GAG biosynthetic gene cluster is present in the genomes of members of the Pezizomycotina subphylum of the Ascomycota including a number of plant-pathogenic fungi and a single basidiomycete species, Trichosporon asahii, likely a result of recent horizontal gene transfer. The current study demonstrates that the production of cationic, deacetylated exopolysaccharides is a strategy used by both fungi and bacteria for biofilm formation. This study sheds light on the biosynthetic pathways governing the synthesis of galactosaminogalactan (GAG), which plays a key role in A. fumigatus virulence and biofilm formation. We find that bacteria and fungi use similar strategies to synthesize adhesive biofilm exopolysaccharides. The presence of orthologs of the GAG biosynthetic gene clusters in multiple fungi suggests that this exopolysaccharide may also be important in the virulence of other fungal pathogens. Further, these studies establish a molecular mechanism of adhesion in which GAG interacts via charge-charge interactions to bind to both fungal hyphae and other substrates. Finally, the importance of deacetylation in the synthesis of functional GAG and the extracellular localization of this process suggest that inhibition of deacetylation may be an attractive target for the development of novel antifungal therapies.
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Rehman S, Mujtaba Ghauri S, Sabri AN. Impact of Plant Extracts and Antibiotics on Biofilm Formation of Clinical Isolates From Otitis Media. Jundishapur J Microbiol 2016; 9:e29483. [PMID: 27099692 PMCID: PMC4834028 DOI: 10.5812/jjm.29483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/22/2015] [Accepted: 09/23/2015] [Indexed: 11/23/2022] Open
Abstract
Background: Otitis media can lead to severe health consequences, and is the most common reason for antibiotic prescriptions and biofilm-mediated infections. However, the increased pattern of drug resistance in biofilm forming bacteria complicates the treatment of such infections. Objectives: This study was aimed to estimate the biofilm formation potential of the clinical isolates of otitis media, and to evaluate the efficacy of antibiotics and plant extracts as alternative therapeutic agents in biofilm eradication. Materials and Methods: The ear swab samples collected from the otitis media patients visiting the Mayo Hospital in Lahore were processed to isolate the bacteria, which were characterized using morphological, biochemical, and molecular (16S rRNA ribotyping) techniques. Then, the minimum inhibitory concentrations (MICs) of the antibiotics and crude plant extracts were measured against the isolates. The cell surface hydrophobicity and biofilm formation potential were determined, both qualitatively and quantitatively, with and without antibiotics. Finally, the molecular characterization of the biofilm forming proteins was done by amplifying the ica operon. Results: Pseudomonas aeruginosa (KC417303-05), Staphylococcus hemolyticus (KC417306), and Staphylococcus hominis (KC417307) were isolated from the otitis media specimens. Among the crude plant extracts, Acacia arabica showed significant antibacterial characteristics (MIC up to 13 mg/ml), while these isolates exhibited sensitivity towards ciprofloxacin (MIC 0.2 µg/mL). All of the bacterial strains had hydrophobic cellular surfaces that helped in their adherence to abiotic surfaces, leading to strong biofilm formation potential (up to 7 days). Furthermore, the icaC gene encoding polysaccharide intercellular adhesion protein was amplified from S. hemolyticus. Conclusions: The bacterial isolates exhibited strong biofilm formation potential, while the extracts of Acacia arabica significantly inhibited biofilm formation among the isolates and, therefore, could be executed in the development of cost-effective biofilm inhibitor medicines.
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Affiliation(s)
- Saba Rehman
- Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
- Department of Microbiology and Molecular Genetics, The Women University Multan, Multan, Pakistan
| | - Shahbaz Mujtaba Ghauri
- Department of Ear, Nose and Throat, Mayo Hospital, King Edward Medical University, Lahore, Pakistan
| | - Anjum Nasim Sabri
- Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
- Corresponding author: Anjum Nasim Sabri, Department of Microbiology and Molecular Genetics, Quaid-e-Azam Campus, University of the Punjab, Lahore-54590, Pakistan. Tel: +92-4235952833, Fax: +92-4299230481, E-mail:
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Vuong C, Yeh AJ, Cheung GYC, Otto M. Investigational drugs to treat methicillin-resistant Staphylococcus aureus. Expert Opin Investig Drugs 2015; 25:73-93. [PMID: 26536498 DOI: 10.1517/13543784.2016.1109077] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Staphylococcus aureus remains one of the leading causes of morbidity and mortality worldwide. This is to a large extent due to antibiotic-resistant strains, in particular methicillin-resistant S. aureus (MRSA). While the toll of invasive MRSA infections appears to decrease in U.S. hospitals, the rate of community-associated MRSA infections remains constant and there is a surge of MRSA in many other countries, a situation that calls for continuing if not increased efforts to find novel strategies to combat MRSA infections. AREAS COVERED This review provides an overview of current investigational drugs and therapeutic antibodies against S. aureus in early clinical development (up to phase II clinical development). It includes a short description of the mechanism of action and a presentation of microbiological and clinical data. EXPERT OPINION Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and therapies, such as anti-virulence drugs, as well as a more informed selection of targets for vaccination efforts against MRSA. This developing portfolio of novel anti-staphylococcal drugs will hopefully provide us with additional and more efficient ways to combat MRSA infections in the near future and prevent us from running out of treatment options, even if new resistances arise.
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Affiliation(s)
- Cuong Vuong
- a Principal Scientist/Laboratory Head, Bacteriology , AiCuris GmbH & Co. KG, Friedrich-Ebert-Str. 475/Geb. 302, 42117 Wuppertal , Germany
| | - Anthony J Yeh
- b Post-baccalaureate IRTA, Laboratory of Bacteriology , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
| | - Gordon Y C Cheung
- c Staff Scientist, National Institute of Allergy and Infectious Diseases , National Institutes of Health, Laboratory of Bacteriology , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
| | - Michael Otto
- d Senior Investigator, National Institute of Allergy and Infectious Diseases , National Institutes of Health, Laboratory of Bacteriology , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
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Jennings LK, Storek KM, Ledvina HE, Coulon C, Marmont LS, Sadovskaya I, Secor PR, Tseng BS, Scian M, Filloux A, Wozniak DJ, Howell PL, Parsek MR. Pel is a cationic exopolysaccharide that cross-links extracellular DNA in the Pseudomonas aeruginosa biofilm matrix. Proc Natl Acad Sci U S A 2015; 112:11353-8. [PMID: 26311845 PMCID: PMC4568648 DOI: 10.1073/pnas.1503058112] [Citation(s) in RCA: 384] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biofilm formation is a complex, ordered process. In the opportunistic pathogen Pseudomonas aeruginosa, Psl and Pel exopolysaccharides and extracellular DNA (eDNA) serve as structural components of the biofilm matrix. Despite intensive study, Pel's chemical structure and spatial localization within mature biofilms remain unknown. Using specialized carbohydrate chemical analyses, we unexpectedly found that Pel is a positively charged exopolysaccharide composed of partially acetylated 1→4 glycosidic linkages of N-acetylgalactosamine and N-acetylglucosamine. Guided by the knowledge of Pel's sugar composition, we developed a tool for the direct visualization of Pel in biofilms by combining Pel-specific Wisteria floribunda lectin staining with confocal microscopy. The results indicate that Pel cross-links eDNA in the biofilm stalk via ionic interactions. Our data demonstrate that the cationic charge of Pel is distinct from that of other known P. aeruginosa exopolysaccharides and is instrumental in its ability to interact with other key biofilm matrix components.
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Affiliation(s)
- Laura K Jennings
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Kelly M Storek
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Hannah E Ledvina
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Charlène Coulon
- Equipe Biochimie des Produits Aquatiques, Université du Littoral-Côte d'Opale, 62327 Boulogne-sur-mer, France
| | - Lindsey S Marmont
- Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A1; Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Irina Sadovskaya
- Equipe Biochimie des Produits Aquatiques, Université du Littoral-Côte d'Opale, 62327 Boulogne-sur-mer, France
| | - Patrick R Secor
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Boo Shan Tseng
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Michele Scian
- School of Pharmacy, University of Washington, Seattle, WA, 98195
| | - Alain Filloux
- Division of Cell and Molecular Biology, Faculty of Natural Science, Center for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; Department of Microbiology, The Ohio State University, Columbus, OH 43210; Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210
| | - P Lynne Howell
- Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A1; Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA 98195;
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Biofilms in chronic rhinosinusitis: what is new and where next? The Journal of Laryngology & Otology 2015; 129:744-51. [DOI: 10.1017/s0022215115001620] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AbstractBackground:Chronic rhinosinusitis is a common, heterogeneous condition. An effective means of mitigating disease in chronic rhinosinusitis patients remains elusive. A variety of causes have been implicated, with the biofilm theory gaining increasing prominence.Objective:This article reviews the literature on the role of biofilms in chronic rhinosinusitis, in terms of pathophysiology and with regard to avenues for future treatment.Methods:A systematic review of case series was performed using databases with independently developed search strategies, including Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane library, and Zetoc, in addition to conference proceedings and a manual search of literature, with the last search conducted on 18 January 2014. The search terms included the following, used in various combinations to maximise the yield of articles identified: ‘biofilms’, ‘chronic rhinosinusitis’, ‘DNase’, ‘extracellular DNA’ and ‘biofilm dispersal’.Results:The existing evidence lends further support for the role of biofilms (particularly the Staphylococcus aureus phenotype) in more severe, recalcitrant disease and poorer surgical outcomes.Conclusion:Multimodality treatment, with a shift in paradigm to incorporate anti-biofilm strategies, is likely to form the mainstay of future recalcitrant chronic rhinosinusitis management.
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Whitfield GB, Marmont LS, Howell PL. Enzymatic modifications of exopolysaccharides enhance bacterial persistence. Front Microbiol 2015; 6:471. [PMID: 26029200 PMCID: PMC4432689 DOI: 10.3389/fmicb.2015.00471] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/29/2015] [Indexed: 12/25/2022] Open
Abstract
Biofilms are surface-attached communities of bacterial cells embedded in a self-produced matrix that are found ubiquitously in nature. The biofilm matrix is composed of various extracellular polymeric substances, which confer advantages to the encapsulated bacteria by protecting them from eradication. The matrix composition varies between species and is dependent on the environmental niche that the bacteria inhabit. Exopolysaccharides (EPS) play a variety of important roles in biofilm formation in numerous bacterial species. The ability of bacteria to thrive in a broad range of environmental settings is reflected in part by the structural diversity of the EPS produced both within individual bacterial strains as well as by different species. This variability is achieved through polymerization of distinct sugar moieties into homo- or hetero-polymers, as well as post-polymerization modification of the polysaccharide. Specific enzymes that are unique to the production of each polymer can transfer or remove non-carbohydrate moieties, or in other cases, epimerize the sugar units. These modifications alter the physicochemical properties of the polymer, which in turn can affect bacterial pathogenicity, virulence, and environmental adaptability. Herein, we review the diversity of modifications that the EPS alginate, the Pel polysaccharide, Vibrio polysaccharide, cepacian, glycosaminoglycans, and poly-N-acetyl-glucosamine undergo during biosynthesis. These are EPS produced by human pathogenic bacteria for which studies have begun to unravel the effect modifications have on their physicochemical and biological properties. The biological advantages these polymer modifications confer to the bacteria that produce them will be discussed. The expanding list of identified modifications will allow future efforts to focus on linking these modifications to specific biosynthetic genes and biofilm phenotypes.
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Affiliation(s)
- Gregory B Whitfield
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Lindsey S Marmont
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children Toronto, ON, Canada ; Department of Biochemistry, Faculty of Medicine, University of Toronto Toronto, ON, Canada
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Hobley L, Harkins C, MacPhee CE, Stanley-Wall NR. Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes. FEMS Microbiol Rev 2015; 39:649-69. [PMID: 25907113 PMCID: PMC4551309 DOI: 10.1093/femsre/fuv015] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2015] [Indexed: 01/24/2023] Open
Abstract
Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars. Examining the structure and function of the biofilm extracellular matrix.
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Affiliation(s)
- Laura Hobley
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Catriona Harkins
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Differential expression and roles of Staphylococcus aureus virulence determinants during colonization and disease. mBio 2015; 6:e02272-14. [PMID: 25691592 PMCID: PMC4337569 DOI: 10.1128/mbio.02272-14] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive, commensal bacterium known to asymptomatically colonize the human skin, nares, and gastrointestinal tract. Colonized individuals are at increased risk for developing S. aureus infections, which range from mild skin and soft tissue infections to more severe diseases, such as endocarditis, bacteremia, sepsis, and osteomyelitis. Different virulence factors are required for S. aureus to infect different body sites. In this study, virulence gene expression was analyzed in two S. aureus isolates during nasal colonization, bacteremia and in the heart during sepsis. These models were chosen to represent the stepwise progression of S. aureus from an asymptomatic colonizer to an invasive pathogen. Expression of 23 putative S. aureus virulence determinants, representing protein and carbohydrate adhesins, secreted toxins, and proteins involved in metal cation acquisition and immune evasion were analyzed. Consistent upregulation of sdrC, fnbA, fhuD, sstD, and hla was observed in the shift between colonization and invasive pathogen, suggesting a prominent role for these genes in staphylococcal pathogenesis. Finally, gene expression data were correlated to the roles of the genes in pathogenesis by using knockout mutants in the animal models. These results provide insights into how S. aureus modifies virulence gene expression between commensal and invasive pathogens. Many bacteria, such as Staphylococcus aureus, asymptomatically colonize human skin and nasal passages but can also cause invasive diseases, such as bacteremia, pneumonia, sepsis, and osteomyelitis. The goal of this study was to analyze differences in the expression of selected S. aureus genes during a commensal lifestyle and as an invasive pathogen to gain insight into the commensal-to-pathogen transition and how a bacterial pathogen adapts to different environments within a host (e.g., from nasal colonization to invasive pathogen). The gene expression data were also used to select genes for which to construct knockout mutants to assess the role of several proteins in nasal colonization and lethal bacteremia. These results not only provide insight into the factors involved in S. aureus disease pathogenesis but also provide potential therapeutic targets.
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