1
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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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2
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Crosby HA, Keim K, Kwiecinski JM, Langouët-Astrié CJ, Oshima K, LaRivière WB, Schmidt EP, Horswill AR. Host-derived protease promotes aggregation of Staphylococcus aureus by cleaving the surface protein SasG. mBio 2024; 15:e0348323. [PMID: 38511930 PMCID: PMC11005337 DOI: 10.1128/mbio.03483-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/21/2024] [Indexed: 03/22/2024] Open
Abstract
Staphylococcus aureus is one of the leading causes of hospital-acquired infections, many of which begin following attachment and accumulation on indwelling medical devices or diseased tissue. These infections are often linked to the establishment of biofilms, but another often overlooked key characteristic allowing S. aureus to establish persistent infection is the formation of planktonic aggregates. Such aggregates are physiologically similar to biofilms and protect pathogens from innate immune clearance and increase antibiotic tolerance. The cell-wall-associated protein SasG has been implicated in biofilm formation via mechanisms of intercellular aggregation but the mechanism in the context of disease is largely unknown. We have previously shown that the expression of cell-wall-anchored proteins involved in biofilm formation is controlled by the ArlRS-MgrA regulatory cascade. In this work, we demonstrate that the ArlRS two-component system controls aggregation, by repressing the expression of sasG by activation of the global regulator MgrA. We also demonstrate that SasG must be proteolytically processed by a non-staphylococcal protease to induce aggregation and that strains expressing functional full-length sasG aggregate significantly upon proteolysis by a mucosal-derived host protease found in human saliva. We used fractionation and N-terminal sequencing to demonstrate that human trypsin within saliva cleaves within the A domain of SasG to expose the B domain and induce aggregation. Finally, we demonstrated that SasG is involved in virulence during mouse lung infection. Together, our data point to SasG, its processing by host proteases, and SasG-driven aggregation as important elements of S. aureus adaptation to the host environment.IMPORTANCEHere, we demonstrate that the Staphylococcus aureus surface protein SasG is important for cell-cell aggregation in the presence of host proteases. We show that the ArlRS two-component regulatory system controls SasG levels through the cytoplasmic regulator MgrA. We identified human trypsin as the dominant protease triggering SasG-dependent aggregation and demonstrated that SasG is important for S. aureus lung infection. The discovery that host proteases can induce S. aureus aggregation contributes to our understanding of how this pathogen establishes persistent infections. The observations in this study demonstrate the need to strengthen our knowledge of S. aureus surface adhesin function and processing, regulation of adhesin expression, and the mechanisms that promote biofilm formation to develop strategies for preventing chronic infections.
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Affiliation(s)
- Heidi A. Crosby
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Klara Keim
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Jakub M. Kwiecinski
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Christophe J. Langouët-Astrié
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Kaori Oshima
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Wells B. LaRivière
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Eric P. Schmidt
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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Marchianò V, Duarte AC, Agún S, Luque S, Marcet I, Fernández L, Matos M, Blanco MDC, García P, Gutiérrez G. Phage Lytic Protein CHAPSH3b Encapsulated in Niosomes and Gelatine Films. Microorganisms 2024; 12:119. [PMID: 38257944 PMCID: PMC10819965 DOI: 10.3390/microorganisms12010119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
Antimicrobial resistance (AMR) has emerged as a global health challenge, sparking worldwide interest in exploring the antimicrobial potential of natural compounds as an alternative to conventional antibiotics. In recent years, one area of focus has been the utilization of bacteriophages and their derivative proteins. Specifically, phage lytic proteins, or endolysins, are specialized enzymes that induce bacterial cell lysis and can be efficiently produced and purified following overexpression in bacteria. Nonetheless, a significant limitation of these proteins is their vulnerability to certain environmental conditions, which may impair their effectiveness. Encapsulating endolysins in vesicles could mitigate this issue by providing added protection to the proteins, enabling controlled release, and enhancing their stability, particularly at temperatures around 4 °C. In this work, the chimeric lytic protein CHAPSH3b was encapsulated within non-ionic surfactant-based vesicles (niosomes) created using the thin film hydrating method (TFH). These protein-loaded niosomes were then characterized, revealing sizes in the range of 30-80 nm, zeta potentials between 30 and 50 mV, and an encapsulation efficiency (EE) of 50-60%. Additionally, with the objective of exploring their potential application in the food industry, these endolysin-loaded niosomes were incorporated into gelatine films. This was carried out to evaluate their stability and antimicrobial efficacy against Staphylococcus aureus.
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Affiliation(s)
- Verdiana Marchianò
- Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain (M.d.C.B.)
- Department of Chemical and Environmental Engineering, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain; (S.L.); (I.M.); (M.M.)
| | - Ana Catarina Duarte
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300 Villaviciosa, Spain; (A.C.D.); (S.A.); (L.F.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Seila Agún
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300 Villaviciosa, Spain; (A.C.D.); (S.A.); (L.F.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Susana Luque
- Department of Chemical and Environmental Engineering, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain; (S.L.); (I.M.); (M.M.)
| | - Ismael Marcet
- Department of Chemical and Environmental Engineering, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain; (S.L.); (I.M.); (M.M.)
| | - Lucía Fernández
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300 Villaviciosa, Spain; (A.C.D.); (S.A.); (L.F.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - María Matos
- Department of Chemical and Environmental Engineering, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain; (S.L.); (I.M.); (M.M.)
- Instituto Universitario de Biotecnología de Asturias, University of Oviedo, 33006 Oviedo, Spain
| | - Mª del Carmen Blanco
- Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain (M.d.C.B.)
- Instituto Universitario de Biotecnología de Asturias, University of Oviedo, 33006 Oviedo, Spain
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300 Villaviciosa, Spain; (A.C.D.); (S.A.); (L.F.)
- DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Gemma Gutiérrez
- Department of Chemical and Environmental Engineering, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain; (S.L.); (I.M.); (M.M.)
- Instituto Universitario de Biotecnología de Asturias, University of Oviedo, 33006 Oviedo, Spain
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Sabino YNV, Araújo Domingues KCD, Mathur H, Gómez-Mascaraque LG, Drouin G, Martínez-Abad A, Tótola MR, Abreu LM, Cotter PD, Mantovani HC. Exopolysaccharides produced by Bacillus spp. inhibit biofilm formation by Staphylococcus aureus strains associated with bovine mastitis. Int J Biol Macromol 2023; 253:126689. [PMID: 37678679 DOI: 10.1016/j.ijbiomac.2023.126689] [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: 07/25/2023] [Revised: 08/22/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
Bovine mastitis is a costly disease in the dairy sector worldwide. Here the objective was to identify and characterize anti-biofilm compounds produced by Bacillus spp. against S. aureus associated with bovine mastitis. Results showed that cell-free supernatants of three Bacillus strains (out of 33 analysed) reduced S. aureus biofilm formation by approximately 40 % without affecting bacterial growth. The anti-biofilm activity was associated with exopolysaccharides (EPS) secreted by Bacillus spp. The EPS decreased S. aureus biofilm formation in a dose-dependent manner, inhibiting biofilm formation by 83 % at 1 mg/mL. The EPS also showed some biofilm disruption activity (up to 36.4 %), which may be partially mediated by increased expression of the aur gene. The characterization of EPS produced by Bacillus velezensis 87 and B. velezensis TR47II revealed macromolecules with molecular weights of 31.2 and 33.7 kDa, respectively. These macromolecules were composed mainly of glucose (mean = 218.5 μg/mg) and mannose (mean = 241.5 μg/mg) and had similar functional groups (pyranose ring, beta-type glycosidic linkage, and alkynes) as revealed by FT-IR. In conclusion, this study shows the potential applications of EPS produced by B. velezensis as an anti-biofilm compound that could contribute to the treatment of bovine mastitis caused by S. aureus.
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Affiliation(s)
| | | | - Harsh Mathur
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland
| | | | - Gaetan Drouin
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland
| | | | - Marcos Rogério Tótola
- Department of Microbiology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Lucas Magalhães Abreu
- Department of Phytopathology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Paul D Cotter
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland; APC Microbiome Ireland, Cork, Ireland
| | - Hilario Cuquetto Mantovani
- Department of Microbiology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil; Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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Guo Q, Zhan Y, Zhang W, Wang J, Yan Y, Wang W, Lin M. Development and Regulation of the Extreme Biofilm Formation of Deinococcus radiodurans R1 under Extreme Environmental Conditions. Int J Mol Sci 2023; 25:421. [PMID: 38203592 PMCID: PMC10778927 DOI: 10.3390/ijms25010421] [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: 11/08/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/12/2024] Open
Abstract
To grow in various harsh environments, extremophiles have developed extraordinary strategies such as biofilm formation, which is an extremely complex and progressive process. However, the genetic elements and exact mechanisms underlying extreme biofilm formation remain enigmatic. Here, we characterized the biofilm-forming ability of Deinococcus radiodurans in vitro under extreme environmental conditions and found that extremely high concentrations of NaCl or sorbitol could induce biofilm formation. Meantime, the survival ability of biofilm cells was superior to that of planktonic cells in different extreme conditions, such as hydrogen peroxide stress, sorbitol stress, and high UV radiation. Transcriptome profiles of D. radiodurans in four different biofilm development stages further revealed that only 13 matched genes, which are involved in environmental information processing, carbohydrate metabolism, or stress responses, share sequence homology with genes related to the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Overall, 64% of the differentially expressed genes are functionally unknown, indicating the specificity of the regulatory network of D. radiodurans. The mutation of the drRRA gene encoding a response regulator strongly impaired biofilm formation ability, implying that DrRRA is an essential component of the biofilm formation of D. radiodurans. Furthermore, transcripts from both the wild type and the drRRA mutant were compared, showing that the expression of drBON1 (Deinococcus radioduransBON domain-containing protein 1) significantly decreased in the drRRA mutant during biofilm development. Further analysis revealed that the drBON1 mutant lacked the ability to form biofilm and DrRRA, and as a facilitator of biofilm formation, could directly stimulate the transcription of the biofilm-related gene drBON1. Overall, our work highlights a molecular mechanism mediated by the response regulator DrRRA for controlling extreme biofilm formation and thus provides guidance for future studies to investigate novel mechanisms that are used by D. radiodurans to adapt to extreme environments.
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Affiliation(s)
- Qiannan Guo
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yuhua Zhan
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Zhang
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jin Wang
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yongliang Yan
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wenxiu Wang
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Min Lin
- National Key Laboratory of Agricultural Microbiology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Q.G.); (Y.Z.); (W.Z.); (J.W.); (Y.Y.); (W.W.)
- Key Laboratory of Agricultural Microbiome (MARA), Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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6
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Al-Tameemi HM, Al-Hraishawi H, Al-Hejjaj MY, Abdulah NS, Alrafas HR, Dawood YA. Whole genome sequence and comparative genomics analysis of multidrug-resistant Staphylococcus xylosus NM36 isolated from a cow with mastitis in Basrah city. J Genet Eng Biotechnol 2023; 21:163. [PMID: 38060084 DOI: 10.1186/s43141-023-00606-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/14/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Staphylococcus xylosus is a coagulase-negative, gram-positive coccus that is found in the environment and as a commensal organism on the skin and mucosal surfaces of animals. Despite the fact that S. xylosus is considered a nonpathogenic bacterium, several studies have linked S. xylosus to opportunistic infections in both animals and humans. During an investigation of mastitis-causing agents in the governorate of Basrah, Iraq, we identified an antibiotic-resistant strain of S. xylosus NM36 from a milk sample from a cow with chronic mastitis. In addition to robust biofilm formation, multiple antibiotic resistance phenotypes were found. To further understand the genetic background for these phenotypes, the full genome of S. xylosus NM36 was analyzed. RESULTS The genome consisted of a single circular 2,668,086 base pairs chromosome containing 32.8% G + C. There were 2454 protein-coding sequences, 4 ribosomal RNA (rRNA) genes, and 50 transfer RNA (tRNA) genes in the genome. In addition, genetic variation was studied by searching sequence data against a representative reference genome. Consequently, single-nucleotide polymorphism analysis was conducted and showed that there were 46,610 single-nucleotide polymorphisms (SNPs), 523 insertions, and 551 deletions. In order to overcome antibiotics, S. xylosus NM36 had been armed with several antibiotic resistance genes from several groups and families. The genome annotation service in PathoSystems Resource Integration Center (PATRIC) and Rapid Annotation using Subsystem Technology (RAST) annotation servers showed that there are multiple antimicrobial resistance elements, including antibiotic inactivation enzymes (BlaZ family, FosB), antibiotic resistance gene clusters (TcaB, TcaB2, TcaR), proteins involved in methicillin resistance (LytH, FmtA, FemC, HmrB, HmrA), TetR family transcriptional regulators, and efflux pumps conferring antibiotic resistance (NorA). In addition, we investigated and categorized the biofilm and quorum-sensing elements of the NM36 strain and found that it has multiple subsets of biofilm regulators, confirming its pathogenic nature. CONCLUSIONS These findings necessitate a reevaluation of microbial and clinical interventions when dealing with coagulase-negative staphylococci, particularly in the context of studies pertaining to public health. This is the first time, to our knowledge, that the entire genome of S. xylosus has been sequenced in Iraq.
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Affiliation(s)
- Hassan M Al-Tameemi
- Microbiology Department, College of Veterinary Medicine, Basrah University, Basrah, 61004, Iraq.
| | - Husam Al-Hraishawi
- Physiology Department, College of Medicine, Misan University, Amarah, Misan, Iraq
| | - Murtakab Y Al-Hejjaj
- Microbiology Department, College of Veterinary Medicine, Basrah University, Basrah, 61004, Iraq
| | | | - Haider R Alrafas
- Microbiology Department, College of Veterinary Medicine, Basrah University, Basrah, 61004, Iraq
| | - Yessar A Dawood
- Pharmacognosy and Medicinal Plants Department, College of Pharmacy, Basrah University, Basrah, Iraq
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Parmar A, Lakshminarayanan R, Iyer A, Goh ETL, To TY, Yam JKH, Yang L, Newire E, Robertson MC, Prior SH, Breukink E, Madder A, Singh I. Development of teixobactin analogues containing hydrophobic, non-proteogenic amino acids that are highly potent against multidrug-resistant bacteria and biofilms. Eur J Med Chem 2023; 261:115853. [PMID: 37857144 DOI: 10.1016/j.ejmech.2023.115853] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/24/2023] [Accepted: 10/01/2023] [Indexed: 10/21/2023]
Abstract
Teixobactin is a cyclic undecadepsipeptide that has shown excellent potency against multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). In this article, we present the design, synthesis, and antibacterial evaluations of 16 different teixobactin analogues. These simplified analogues contain commercially available hydrophobic, non-proteogenic amino acid residues instead of synthetically challenging expensive L-allo-enduracididine amino acid residue at position 10 together with different combinations of arginines at positions 3, 4 and 9. The new teixobactin analogues showed potent antibacterial activity against a broad panel of Gram-positive bacteria, including MRSA and VRE strains. Our work also presents the first demonstration of the potent antibiofilm activity of teixobactin analogoues against Staphylococcus species associated with serious chronic infections. Our results suggest that the use of hydrophobic, non-proteogenic amino acids at position 10 in combination with arginine at positions 3, 4 and 9 holds the key to synthesising a new generation of highly potent teixobactin analogues to tackle resistant bacterial infections and biofilms.
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Affiliation(s)
- Anish Parmar
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool, L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX, Liverpool, UK
| | - Rajamani Lakshminarayanan
- Singapore Eye Research Institute, The Academia, Discovery Tower Level 6, 20 College Road, 169857, Singapore
| | - Abhishek Iyer
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 (S4), B-9000, Ghent, Belgium
| | - Eunice Tze Leng Goh
- Singapore Eye Research Institute, The Academia, Discovery Tower Level 6, 20 College Road, 169857, Singapore
| | - Tsz Ying To
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool, L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX, Liverpool, UK
| | - Joey Kuok Hoong Yam
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 637551, Singapore; School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological University, 639798, Singapore
| | - Enas Newire
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool, L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX, Liverpool, UK
| | - Maria C Robertson
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool, L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX, Liverpool, UK
| | - Stephen H Prior
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Green Lane, Lincoln, LN6 7DL, United Kingdom
| | - Eefjan Breukink
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584, CH, Utrecht, the Netherlands
| | - Annemieke Madder
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 (S4), B-9000, Ghent, Belgium
| | - Ishwar Singh
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool, L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX, Liverpool, UK.
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8
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Francis D, Veeramanickathadathil Hari G, Koonthanmala Subash A, Bhairaddy A, Joy A. The biofilm proteome of Staphylococcus aureus and its implications for therapeutic interventions to biofilm-associated infections. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 138:327-400. [PMID: 38220430 DOI: 10.1016/bs.apcsb.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Staphylococcus aureus is a major healthcare concern due to its ability to inflict life-threatening infections and evolve antibiotic resistance at an alarming pace. It is frequently associated with hospital-acquired infections, especially device-associated infections. Systemic infections due to S. aureus are difficult to treat and are associated with significant mortality and morbidity. The situation is worsened by the ability of S. aureus to form social associations called biofilms. Biofilms embed a community of cells with the ability to communicate with each other and share resources within a polysaccharide or protein matrix. S. aureus establish biofilms on tissues and conditioned abiotic surfaces. Biofilms are hyper-tolerant to antibiotics and help evade host immune responses. Biofilms exacerbate the severity and recalcitrance of device-associated infections. The development of a biofilm involves various biomolecules, such as polysaccharides, proteins and nucleic acids, contributing to different structural and functional roles. Interconnected signaling pathways and regulatory molecules modulate the expression of these molecules. A comprehensive understanding of the molecular biology of biofilm development would help to devise effective anti-biofilm therapeutics. Although bactericidal agents, antimicrobial peptides, bacteriophages and nano-conjugated anti-biofilm agents have been employed with varying levels of success, there is still a requirement for effective and clinically viable anti-biofilm therapeutics. Proteins that are expressed and utilized during biofilm formation, constituting the biofilm proteome, are a particularly attractive target for anti-biofilm strategies. The proteome can be explored to identify potential anti-biofilm drug targets and utilized for rational drug discovery. With the aim of uncovering the biofilm proteome, this chapter explores the mechanism of biofilm formation and its regulation. Furthermore, it explores the antibiofilm therapeutics targeted against the biofilm proteome.
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Affiliation(s)
- Dileep Francis
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India.
| | | | | | - Anusha Bhairaddy
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India
| | - Atheene Joy
- Department of Life Sciences, Kristu Jayanti College (Autonomous), Bengaluru, India
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9
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Park I, Lee JH, Ma JY, Tan Y, Lee J. Antivirulence activities of retinoic acids against Staphylococcus aureus. Front Microbiol 2023; 14:1224085. [PMID: 37771707 PMCID: PMC10525321 DOI: 10.3389/fmicb.2023.1224085] [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: 05/17/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023] Open
Abstract
Multidrug-resistant bacteria such as Staphylococcus aureus constitute a global health problem. Gram-positive S. aureus secretes various toxins associated with its pathogenesis, and its biofilm formation plays an important role in antibiotic tolerance and virulence. Hence, we investigated if the metabolites of vitamin A1 might diminish S. aureus biofilm formation and toxin production. Of the three retinoic acids examined, 13-cis-retinoic acid at 10 μg/mL significantly decreased S. aureus biofilm formation without affecting its planktonic cell growth (MIC >400 μg/mL) and also inhibited biofilm formation by Staphylococcus epidermidis (MIC >400 μg/mL), but less affected biofilm formation by a uropathogenic Escherichia coli strain, a Vibrio strain, or a fungal Candida strain. Notably, 13-cis-retinoic acid and all-trans-retinoic acid significantly inhibited the hemolytic activity and staphyloxanthin production by S. aureus. Furthermore, transcriptional analysis disclosed that 13-cis-retinoic acid repressed the expressions of virulence- and biofilm-related genes, such as the two-component arlRS system, α-hemolysin hla, nuclease (nuc1 and nuc2), and psmα (phenol soluble modulins α) in S. aureus. In addition, plant and nematode toxicity assays showed that 13-cis-retinoic acid was only mildly toxic at concentrations many folds higher than its effective antibiofilm concentrations. These findings suggest that metabolites of vitamin A1, particularly 13-cis-retinoic acid, might be useful for suppressing biofilm formation and the virulence characteristics of S. aureus.
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Affiliation(s)
- Inji Park
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea
| | - Jin-Hyung Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea
| | - Jin Yeul Ma
- Korea Institute of Oriental Medicine, Daegu, Republic of Korea
| | - Yulong Tan
- Special Food Research Institute, Qingdao Agricultural University, Qingdao, China
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea
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10
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Gómez-Arrebola C, Hernandez SB, Culp EJ, Wright GD, Solano C, Cava F, Lasa I. Staphylococcus aureus susceptibility to complestatin and corbomycin depends on the VraSR two-component system. Microbiol Spectr 2023; 11:e0037023. [PMID: 37646518 PMCID: PMC10581084 DOI: 10.1128/spectrum.00370-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
The overuse of antibiotics in humans and livestock has driven the emergence and spread of antimicrobial resistance and has therefore prompted research on the discovery of novel antibiotics. Complestatin (Cm) and corbomycin (Cb) are glycopeptide antibiotics with an unprecedented mechanism of action that is active even against methicillin-resistant and daptomycin-resistant Staphylococcus aureus. They bind to peptidoglycan and block the activity of peptidoglycan hydrolases required for remodeling the cell wall during growth. Bacterial signaling through two-component transduction systems (TCSs) has been associated with the development of S. aureus antimicrobial resistance. However, the role of TCSs in S. aureus susceptibility to Cm and Cb has not been previously addressed. In this study, we determined that, among all 16 S. aureus TCSs, VraSR is the only one controlling the susceptibility to Cm and Cb. Deletion of vraSR increased bacterial susceptibility to both antibiotics. Epistasis analysis with members of the vraSR regulon revealed that deletion of spdC, which encodes a membrane protein that scaffolds SagB for cleavage of peptidoglycan strands to achieve physiological length, in the vraSR mutant restored Cm and Cb susceptibility to wild-type levels. Moreover, deletion of either spdC or sagB in the wild-type strain increased resistance to both antibiotics. Further analyses revealed a significant rise in the relative amount of peptidoglycan and its total degree of cross-linkage in ΔspdC and ΔsagB mutants compared to the wild-type strain, suggesting that these changes in the cell wall provide resistance to the damaging effect of Cm and Cb. IMPORTANCE Although Staphylococcus aureus is a common colonizer of the skin and digestive tract of humans and many animals, it is also a versatile pathogen responsible for causing a wide variety and number of infections. Treatment of these infections requires the bacteria to be constantly exposed to antibiotic treatment, which facilitates the selection of antibiotic-resistant strains. The development of new antibiotics is, therefore, urgently needed. In this paper, we investigated the role of the sensory system of S. aureus in susceptibility to two new antibiotics: corbomycin and complestatin. The results shed light on the cell-wall synthesis processes that are affected by the presence of the antibiotic and the sensory system responsible for coordinating their activity.
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Affiliation(s)
- Carmen Gómez-Arrebola
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Sara B. Hernandez
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Elizabeth J. Culp
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Gerard D. Wright
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Felipe Cava
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
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11
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Fu T, Fan Z, Li Y, Li Z, Zhao H, Feng Y, Xue G, Cui J, Yan C, Gan L, Feng J, Yuan J, You F. Roles of the Crp/Fnr Family Regulator ArcR in the Hemolysis and Biofilm of Staphylococcus aureus. Microorganisms 2023; 11:1656. [PMID: 37512829 PMCID: PMC10384999 DOI: 10.3390/microorganisms11071656] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
Staphylococcus aureus is an opportunistic human pathogen that is often involved in severe infections such as pneumonia and sepsis in which bacterial virulence factors play a key role. Infections caused by S. aureus are often difficult to eradicate, particularly when they are associated with biofilm. The physiological roles of the Crp/Fnr family regulator ArcR are elusive in S. aureus. In this study, it was found that the deletion of arcR increased the hemolytic ability and biofilm formation in S. aureus. Differential gene expression analysis by RNA-seq and real-time quantitative reverse transcription PCR showed that genes associated with hemolytic ability (hla and hlb) and biofilm formation (icaA, icaB, icaC and icaD) were significantly upregulated compared with those in the wild-type strain. The results revealed that ArcR regulated the expression of the hla and ica operon by binding to their promoter regions, respectively. This study provided new insights into the functional importance of ArcR in regulating the virulence and biofilm of S. aureus.
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Affiliation(s)
- Tongtong Fu
- School of Basic Medical Sciences, Peking University, Beijing 100020, China
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Zheng Fan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Yujie Li
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zhoufei Li
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Hanqing Zhao
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Yanling Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Guanhua Xue
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Jinghua Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Chao Yan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Lin Gan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Junxia Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Jing Yuan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing 100020, China
| | - Fuping You
- School of Basic Medical Sciences, Peking University, Beijing 100020, China
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12
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Biology and Regulation of Staphylococcal Biofilm. Int J Mol Sci 2023; 24:ijms24065218. [PMID: 36982293 PMCID: PMC10049468 DOI: 10.3390/ijms24065218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/15/2023] [Accepted: 03/03/2023] [Indexed: 03/11/2023] Open
Abstract
Despite continuing progress in medical and surgical procedures, staphylococci remain the major Gram-positive bacterial pathogens that cause a wide spectrum of diseases, especially in patients requiring the utilization of indwelling catheters and prosthetic devices implanted temporarily or for prolonged periods of time. Within the genus, if Staphylococcus aureus and S. epidermidis are prevalent species responsible for infections, several coagulase-negative species which are normal components of our microflora also constitute opportunistic pathogens that are able to infect patients. In such a clinical context, staphylococci producing biofilms show an increased resistance to antimicrobials and host immune defenses. Although the biochemical composition of the biofilm matrix has been extensively studied, the regulation of biofilm formation and the factors contributing to its stability and release are currently still being discovered. This review presents and discusses the composition and some regulation elements of biofilm development and describes its clinical importance. Finally, we summarize the numerous and various recent studies that address attempts to destroy an already-formed biofilm within the clinical context as a potential therapeutic strategy to avoid the removal of infected implant material, a critical event for patient convenience and health care costs.
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13
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Sharaf M, Sewid AH, Hamouda HI, Elharrif MG, El-Demerdash AS, Alharthi A, Hashim N, Hamad AA, Selim S, Alkhalifah DHM, Hozzein WN, Abdalla M, Saber T. Rhamnolipid-Coated Iron Oxide Nanoparticles as a Novel Multitarget Candidate against Major Foodborne E. coli Serotypes and Methicillin-Resistant S. aureus. Microbiol Spectr 2022; 10:e0025022. [PMID: 35852338 PMCID: PMC9430161 DOI: 10.1128/spectrum.00250-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 06/21/2022] [Indexed: 01/28/2023] Open
Abstract
Surface-growing antibiotic-resistant pathogenic bacteria such as Escherichia coli and Staphylococcus aureus are emerging as a global health challenge due to dilemmas in clinical treatment. Furthermore, their pathogenesis, including increasingly serious antimicrobial resistance and biofilm formation, makes them challenging to treat by conventional therapy. Therefore, the development of novel antivirulence strategies will undoubtedly provide a path forward in combatting these resistant bacterial infections. In this regard, we developed novel biosurfactant-coated nanoparticles to combine the antiadhesive/antibiofilm properties of rhamnolipid (RHL)-coated Fe3O4 nanoparticles (NPs) with each of the p-coumaric acid (p-CoA) and gallic acid (GA) antimicrobial drugs by using the most available polymer common coatings (PVA) to expand the range of effective antibacterial drugs, as well as a mechanism for their synergistic effect via a simple method of preparation. Mechanistically, the average size of bare Fe3O4 NPs was ~15 nm, while RHL-coated Fe3O4@PVA@p-CoA/GA was about ~254 nm, with a drop in zeta potential from -18.7 mV to -34.3 mV, which helped increase stability. Our data show that RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs can remarkably interfere with bacterial growth and significantly inhibited biofilm formation to more than 50% via downregulating IcaABCD and CsgBAC operons, which are responsible for slime layer formation and curli fimbriae production in S. aureus and E. coli, respectively. The novelty regarding the activity of RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs reveals their potential effect as an alternative multitarget antivirulence candidate to minimize infection severity by inhibiting biofilm development. Therefore, they could be used in antibacterial coatings and wound dressings in the future. IMPORTANCE Antimicrobial resistance poses a great threat and challenge to humanity. Therefore, the search for alternative ways to target and eliminate microbes from plant, animal, and marine microorganisms is one of the world's concerns today. Furthermore, the extraordinary capacity of S. aureus and E. coli to resist standard antibacterial drugs is the dilemma of all currently used remedies. Methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) have become widespread, leading to no remedies being able to treat these threatening pathogens. The most widely recognized serotypes that cause severe foodborne illness are E. coli O157:H7, O26:H11, and O78:H10, and they display increasing antimicrobial resistance rates. Therefore, there is an urgent need for an effective therapy that has dual action to inhibit biofilm formation and decrease bacterial growth. In this study, the synthesized RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs have interesting properties, making them excellent candidates for targeted drug delivery by inhibiting bacterial growth and downregulating biofilm-associated IcaABCD and CsgBAC gene loci.
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Affiliation(s)
- Mohamed Sharaf
- Department of Biochemistry, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo, Egypt
- Department of Biochemistry and Molecular Biology, College of Marine Life Sciences, Ocean University of China, Qingdao, People’s Republic of China
| | - Alaa H. Sewid
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
- Department of Biomedical and Diagnostic Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - H. I. Hamouda
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
- Processes Design and Development Department, Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt
| | - Mohamed G. Elharrif
- Department of Basic Medical Sciences, Shaqra University, Shaqraa, Kingdom of Saudi Arabia
| | | | - Afaf Alharthi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Nada Hashim
- General Practitioner, Faculty of Medicine, University of Gezira, Wad Medani, Sudan
| | - Anas Abdullah Hamad
- Department of Medical Laboratory Techniques, Al Maarif University College, Al Anbar, Ramadi, Iraq
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia
| | - Dalal Hussien M. Alkhalifah
- Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Wael N. Hozzein
- Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Mohnad Abdalla
- Department of Biotechnology, Faculty of Science and Technology, Shendi University, Shendi, Nher Anile, Sudan
| | - Taisir Saber
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Zagazig University, Zagazig, Egypt
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14
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Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:microorganisms10061239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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15
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Menendez-Gil P, Catalan-Moreno A, Caballero CJ, Toledo-Arana A. Staphylococcus aureus ftnA 3'-Untranslated Region Modulates Ferritin Production Facilitating Growth Under Iron Starvation Conditions. Front Microbiol 2022; 13:838042. [PMID: 35572681 PMCID: PMC9093591 DOI: 10.3389/fmicb.2022.838042] [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: 12/17/2021] [Accepted: 03/31/2022] [Indexed: 11/17/2022] Open
Abstract
Iron acquisition and modulation of its intracellular concentration are critical for the development of all living organisms. So far, several proteins have been described to be involved in iron homeostasis. Among them, ferritins act as the major iron storage proteins, sequestering internalized iron and modulating its concentration inside bacterial cells. We previously described that the deletion of the 3’-untranslated region (3’UTR) of the ftnA gene, which codes for ferritin in Staphylococcus aureus, increased the ftnA mRNA and ferritin levels. Here, we show that the ferritin levels are affected by RNase III and PNPase, which target the ftnA 3’UTR. Rifampicin mRNA stability experiments revealed that the half-life of the ftnA mRNA is affected by both RNase III and the ftnA 3’UTR. A transcriptional fusion of the ftnA 3’UTR to the gfp reporter gene decreased green fluorescent protein (GFP) expression, indicating that the ftnA 3’UTR could work as an independent module. Additionally, a chromosomal deletion of the ftnA 3’UTR impaired S. aureus growth under conditions of iron starvation. Overall, this work highlights the biological relevance of the ftnA 3’UTR for iron homeostasis in S. aureus.
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Affiliation(s)
- Pilar Menendez-Gil
- Instituto de Agrobiotecnología (IdAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Navarra, Spain
| | - Arancha Catalan-Moreno
- Instituto de Agrobiotecnología (IdAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Navarra, Spain
| | - Carlos J Caballero
- Instituto de Agrobiotecnología (IdAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Navarra, Spain
| | - Alejandro Toledo-Arana
- Instituto de Agrobiotecnología (IdAB), Consejo Superior de Investigaciones Científicas (CSIC)-Gobierno de Navarra, Navarra, Spain
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16
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Ong ZX, Kannan B, Becker DL. Exploiting transposons in the study of Staphylococcus aureus pathogenesis and virulence. Crit Rev Microbiol 2022; 49:297-317. [PMID: 35438613 DOI: 10.1080/1040841x.2022.2052794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The opportunistic pathogen Staphylococcus aureus has an extremely complex relationship with humans. While the bacteria can exist as a commensal in many, it can cause a wide range of diseases and infections when turned pathogenic. Its presence is a determinant of chronicity and poor prognosis in numerous diseases, and its genomic plasticity causes S. aureus antimicrobial resistance to be one of the most dire contemporary medical problems to solve. Genetic manipulation of S. aureus has led to numerous findings that are vital in the fight against its pathogenesis. The utilisation of transposon mutant libraries for the systematic inspection of the S. aureus genome led to many landmark discoveries pertaining to the bacteria's pathogenicity, antimicrobial resistance acquisition, and virulence regulation. In this review, we describe mutant libraries, and their significant contributions, from various S. aureus strains created with commonly used transposons. The general workflow for the construction of libraries will be presented, along with a discussion of the challenges of undertaking the task of large-scale library construction. As the accessibility of transposon mutant library construction, screening, and analysis increases, this genetic tool could be further exploited in the study of the S. aureus genome.
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Affiliation(s)
- Zi Xin Ong
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Skin Research Institute, Singapore.,Nanyang Institute of Technology in Health and Medicine, Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore
| | - Bavani Kannan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Skin Research Institute, Singapore
| | - David L Becker
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Skin Research Institute, Singapore
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17
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Chen F, Zhang J, Ji HJ, Kim MK, Kim KW, Choi JI, Han SH, Lim S, Seo HS, Ahn KB. Deinococcus radiodurans Exopolysaccharide Inhibits Staphylococcus aureus Biofilm Formation. Front Microbiol 2022; 12:712086. [PMID: 35002990 PMCID: PMC8739996 DOI: 10.3389/fmicb.2021.712086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022] Open
Abstract
Deinococcus radiodurans is an extremely resistant bacterium against extracellular stress owing to on its unique physiological functions and the structure of its cellular constituents. Interestingly, it has been reported that the pattern of alteration in Deinococcus proportion on the skin is negatively correlated with skin inflammatory diseases, whereas the proportion of Staphylococcus aureus was increased in patients with chronic skin inflammatory diseases. However, the biological mechanisms of deinococcal interactions with other skin commensal bacteria have not been studied. In this study, we hypothesized that deinococcal cellular constituents play a pivotal role in preventing S. aureus colonization by inhibiting biofilm formation. To prove this, we first isolated cellular constituents, such as exopolysaccharide (DeinoPol), cell wall (DeinoWall), and cell membrane (DeinoMem), from D. radiodurans and investigated their inhibitory effects on S. aureus colonization and biofilm formation in vitro and in vivo. Among them, only DeinoPol exhibited an anti-biofilm effect without affecting bacterial growth and inhibiting staphylococcal colonization and inflammation in a mouse skin infection model. Moreover, the inhibitory effect was impaired in the Δdra0033 strain, a mutant that cannot produce DeinoPol. Remarkably, DeinoPol not only interfered with S. aureus biofilm formation at early and late stages but also disrupted a preexisting biofilm by inhibiting the production of poly-N-acetylglucosamine (PNAG), a key molecule required for S. aureus biofilm formation. Taken together, the present study suggests that DeinoPol is a key molecule in the negative regulation of S. aureus biofilm formation by D. radiodurans. Therefore, DeinoPol could be applied to prevent and/or treat infections or inflammatory diseases associated with S. aureus biofilms.
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Affiliation(s)
- Fengjia Chen
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, South Korea
| | - Jing Zhang
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea
| | - Hyun Jung Ji
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Min-Kyu Kim
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea
| | - Kyoung Whun Kim
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, South Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea
| | - Sangyong Lim
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology, Daejeon, South Korea
| | - Ho Seong Seo
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology, Daejeon, South Korea
| | - Ki Bum Ahn
- Research Division for Radiation Science, Korea Atomic Energy Research Institute, Jeongeup, South Korea
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18
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Kwok TY, Ma Y, Chua SL. Biofilm dispersal induced by mechanical cutting leads to heightened foodborne pathogen dissemination. Food Microbiol 2021; 102:103914. [PMID: 34809940 DOI: 10.1016/j.fm.2021.103914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 11/28/2022]
Abstract
The biofilm life cycle where bacteria alternate between biofilm and planktonic lifestyles poses major implications in food spoilage and gastrointestinal infections. Recent studies had shown that freshly biofilm-dispersed cells have a unique physiology from planktonic cells, raising the fundamental question if biofilm-dispersed cells and planktonic cells disseminate differently across food surfaces. Mechanical dislodging via cutting can cause biofilm dispersal and eventual food cross-contamination. Here, we showed that biofilm-dispersed bacteria from various foodborne pathogens were transferred from freshly cut surface at a higher rate to the cutting material than that of planktonic bacteria. When the cutting tool was used to cut a fresh surface, more biofilm-dispersed bacteria were disseminated from the cutting tool to the newly cut surface than planktonic bacteria. Our observations were applicable to cutting tools of various materials and cut surfaces, where polystyrene and surfaces with high water content were most susceptible to biofilm transfer, respectively. Simple washing with detergent and mechanical wiping could aid bacterial removal from cutting tools. Our work revealed that biofilm-dispersed cells were transferred at a higher rate than planktonic cells and cutting tool was an important medium for pathogen cross-contamination, thus providing insights in maintaining their cleanliness in food processing industries.
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Affiliation(s)
- Tsz-Yiu Kwok
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Yeping Ma
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Song Lin Chua
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong; State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong; Shenzhen Key Laboratory of Food Biological Safety Control, Shenzhen Research Institute of Hong Kong Polytechnic University, Shenzhen, 518057, China.
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19
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Gutiérrez D, Rodríguez-Rubio L, Ruas-Madiedo P, Fernández L, Campelo AB, Briers Y, Nielsen MW, Pedersen K, Lavigne R, García P, Rodríguez A. Design and Selection of Engineered Lytic Proteins With Staphylococcus aureus Decolonizing Activity. Front Microbiol 2021; 12:723834. [PMID: 34594314 PMCID: PMC8477017 DOI: 10.3389/fmicb.2021.723834] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus causes various infections in humans and animals, the skin being the principal reservoir of this pathogen. The widespread occurrence of methicillin-resistant S. aureus (MRSA) limits the elimination and treatment of this pathogen. Phage lytic proteins have been proven as efficient antimicrobials against S. aureus. Here, a set of 12 engineered proteins based on endolysins were conceptualized to select the most optimal following a stepwise funnel approach assessing parameters including turbidity reduction, minimum inhibitory concentration (MIC), time-kill curves, and antibiofilm assays, as well as testing their stability in a broad range of storage conditions (pH, temperature, and ionic strength). The engineered phage lysins LysRODIΔAmi and ClyRODI-H5 showed the highest specific lytic activity (5 to 50 times higher than the rest), exhibited a shelf-life up to 6 months and remained stable at temperatures up to 50°C and in a pH range from 3 to 9. LysRODIΔAmi showed the lower MIC values against all staphylococcal strains tested. Both proteins were able to kill 6 log units of the strain S. aureus Sa9 within 5 min and could remove preformed biofilms (76 and 65%, respectively). Moreover, LysRODIΔAmi could prevent biofilm formation at low protein concentrations (0.15–0.6 μM). Due to its enhanced antibiofilm properties, LysRODIΔAmi was selected to effectively remove S. aureus contamination in both intact and disrupted keratinocyte monolayers. Notably, this protein did not demonstrate any toxicity toward human keratinocytes, even at high concentrations (22.1 μM). Finally, a pig skin ex vivo model was used to evaluate treatment of artificially contaminated pig skin using LysRODIΔAmi (16.5 μg/cm2). Following an early reduction of S. aureus, a second dose of protein completely eradicated S. aureus. Overall, our results suggest that LysRODIΔAmi is a suitable candidate as antimicrobial agent to prevent and treat staphylococcal skin infections.
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Affiliation(s)
- Diana Gutiérrez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain.,Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Lorena Rodríguez-Rubio
- Laboratory of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Patricia Ruas-Madiedo
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
| | - Lucía Fernández
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
| | - Ana Belén Campelo
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain
| | - Yves Briers
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Martin Weiss Nielsen
- Department of Microbiology and Production, National Food Institute, Technical University of Denmark, Lyngby, Denmark
| | - Karl Pedersen
- Department of Microbiology and Production, National Food Institute, Technical University of Denmark, Lyngby, Denmark
| | - Rob Lavigne
- Laboratory of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
| | - Ana Rodríguez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Asturias, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain
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20
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Bai X, Nakatsu CH, Bhunia AK. Bacterial Biofilms and Their Implications in Pathogenesis and Food Safety. Foods 2021; 10:2117. [PMID: 34574227 PMCID: PMC8472614 DOI: 10.3390/foods10092117] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 08/21/2021] [Accepted: 08/30/2021] [Indexed: 12/28/2022] Open
Abstract
Biofilm formation is an integral part of the microbial life cycle in nature. In food processing environments, bacterial transmissions occur primarily through raw or undercooked foods and by cross-contamination during unsanitary food preparation practices. Foodborne pathogens form biofilms as a survival strategy in various unfavorable environments, which also become a frequent source of recurrent contamination and outbreaks of foodborne illness. Instead of focusing on bacterial biofilm formation and their pathogenicity individually, this review discusses on a molecular level how these two physiological processes are connected in several common foodborne pathogens such as Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Escherichia coli. In addition, biofilm formation by Pseudomonas aeruginosa is discussed because it aids the persistence of many foodborne pathogens forming polymicrobial biofilms on food contact surfaces, thus significantly elevating food safety and public health concerns. Furthermore, in-depth analyses of several bacterial molecules with dual functions in biofilm formation and pathogenicity are highlighted.
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Affiliation(s)
- Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA;
| | - Cindy H. Nakatsu
- Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
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21
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Pant N, Eisen DP. Non-Antimicrobial Adjuvant Strategies to Tackle Biofilm-Related Staphylococcus aureus Prosthetic Joint Infections. Antibiotics (Basel) 2021; 10:antibiotics10091060. [PMID: 34572641 PMCID: PMC8465242 DOI: 10.3390/antibiotics10091060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus frequently causes community- and hospital-acquired infections. S. aureus attachment followed by biofilm formation on tissues and medical devices plays a significant role in the establishment of chronic infections. Staphylococcal biofilms encase bacteria in a matrix and protect the cells from antimicrobials and the immune system, resulting in infections that are highly resistant to treatment. The biology of biofilms is complex and varies between organisms. In this review, we focus our discussion on S. aureus biofilms and describe the stages of their formation. We particularly emphasize genetic and biochemical processes that may be vulnerable to novel treatment approaches. Against this background, we discuss treatment strategies that have been successful in animal models of S. aureus biofilm-related infection and consider their possible use for the prevention and eradication of biofilm-related S. aureus prosthetic joint infection.
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22
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Rozis M, Evangelopoulos DS, Pneumaticos SG. Orthopedic Implant-Related Biofilm Pathophysiology: A Review of the Literature. Cureus 2021; 13:e15634. [PMID: 34306846 PMCID: PMC8278357 DOI: 10.7759/cureus.15634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2021] [Indexed: 11/05/2022] Open
Abstract
Orthopedic implant-related infections remain a major problem even nowadays. Bacterial resistance through biofilm formation, in addition to the limited treatment options available, has resulted in an increased effort to better understand pathophysiology mechanisms. We performed a review of the literature in order to identify major biofilm formation pathways through which possible treatment strategies could arise.
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Affiliation(s)
- Meletis Rozis
- 3rd Orthopaedic Department, National and Kapodistrian University of Athens, KAT Hospital, Athens, GRC
| | | | - Spyros G Pneumaticos
- 3rd Orthopaedic Department, National and Kapodistrian University of Athens, KAT Hospital, Athens, GRC
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23
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Villanueva M, Roch M, Lasa I, Renzoni A, Kelley WL. The Role of ArlRS and VraSR in Regulating Ceftaroline Hypersusceptibility in Methicillin-Resistant Staphylococcus aureus. Antibiotics (Basel) 2021; 10:antibiotics10070821. [PMID: 34356742 PMCID: PMC8300640 DOI: 10.3390/antibiotics10070821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/14/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus infections are a global health problem. New control strategies, including fifth-generation cephalosporins such as ceftaroline, have been developed, however rare sporadic resistance has been reported. Our study aimed to determine whether disruption of two-component environmental signal systems detectably led to enhanced susceptibility to ceftaroline in S. aureus CA-MRSA strain MW2 at sub-MIC concentrations where cells normally continue to grow. A collection of sequential mutants in all fifteen S. aureus non-essential two-component systems (TCS) was first screened for ceftaroline sub-MIC susceptibility, using the spot population analysis profile method. We discovered a role for both ArlRS and VraSR TCS as determinants responsible for MW2 survival in the presence of sub-MIC ceftaroline. Subsequent analysis showed that dual disruption of both arlRS and vraSR resulted in a very strong ceftaroline hypersensitivity phenotype. Genetic complementation analysis confirmed these results and further revealed that arlRS and vraSR likely regulate some common pathway(s) yet to be determined. Our study shows that S. aureus uses particular TCS environmental sensing systems for this type of defense and illustrates the proof of principle that if these TCS were inhibited, the efficacy of certain antibiotics might be considerably enhanced.
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Affiliation(s)
- Maite Villanueva
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1206 Geneva, Switzerland; (M.V.); (M.R.)
- Departament de Investigación y Desarrollo, Bioinsectis SL, 31110 Noain, Spain
| | - Melanie Roch
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1206 Geneva, Switzerland; (M.V.); (M.R.)
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), 31008 Pamplona, Spain;
| | - Adriana Renzoni
- Service of Infectious Diseases, University Hospital and Medical School of Geneva, 1206 Geneva, Switzerland;
| | - William L. Kelley
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1206 Geneva, Switzerland; (M.V.); (M.R.)
- Correspondence: ; Tel.: +41-22-379-5651
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24
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Whittard E, Redfern J, Xia G, Millard A, Ragupathy R, Malic S, Enright MC. Phenotypic and Genotypic Characterization of Novel Polyvalent Bacteriophages With Potent In Vitro Activity Against an International Collection of Genetically Diverse Staphylococcus aureus. Front Cell Infect Microbiol 2021; 11:698909. [PMID: 34295840 PMCID: PMC8290860 DOI: 10.3389/fcimb.2021.698909] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Phage therapy recently passed a key milestone with success of the first regulated clinical trial using systemic administration. In this single-arm non-comparative safety study, phages were administered intravenously to patients with invasive Staphylococcus aureus infections with no adverse reactions reported. Here, we examined features of 78 lytic S. aureus phages, most of which were propagated using a S. carnosus host modified to be broadly susceptible to staphylococcal phage infection. Use of this host eliminates the threat of contamination with staphylococcal prophage - the main vector of S. aureus horizontal gene transfer. We determined the host range of these phages against an international collection of 185 S. aureus isolates with 56 different multilocus sequence types that included multiple representatives of all epidemic MRSA and MSSA clonal complexes. Forty of our 78 phages were able to infect > 90% of study isolates, 15 were able to infect > 95%, and two could infect all 184 clinical isolates, but not a phage-resistant mutant generated in a previous study. We selected the 10 phages with the widest host range for in vitro characterization by planktonic culture time-kill analysis against four isolates:- modified S. carnosus strain TM300H, methicillin-sensitive isolates D329 and 15981, and MRSA isolate 252. Six of these 10 phages were able to rapidly kill, reducing cell numbers of at least three isolates. The four best-performing phages, in this assay, were further shown to be highly effective in reducing 48 h biofilms on polystyrene formed by eight ST22 and eight ST36 MRSA isolates. Genomes of 22 of the widest host-range phages showed they belonged to the Twortvirinae subfamily of the order Caudovirales in three main groups corresponding to Silviavirus, and two distinct groups of Kayvirus. These genomes assembled as single-linear dsDNAs with an average length of 140 kb and a GC content of c. 30%. Phages that could infect > 96% of S. aureus isolates were found in all three groups, and these have great potential as therapeutic candidates if, in future studies, they can be formulated to maximize their efficacy and eliminate emergence of phage resistance by using appropriate combinations.
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Affiliation(s)
- Elliot Whittard
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - James Redfern
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Guoqing Xia
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Andrew Millard
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Roobinidevi Ragupathy
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Sladjana Malic
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Mark C. Enright
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
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25
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Rachmawati D, Kuntaman K, Alimsardjono L. The Correlation between icaA and icaD Genes with Biofilm Formation Staphylococcus epidermidis In Vitro. FOLIA MEDICA INDONESIANA 2021. [DOI: 10.20473/fmi.v55i4.24388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was conducted to identify the presence of icaA and icaD genes in S. epidermidis and to analyze the relationship between the presence of icaA and icaD genes with the ability of in vitro biofilm formation in S. epidermidis. S. epidermidis isolates from patients and healthy people were collected and PCR was examined to detect icaA and icaD genes. which then continued to examine the ability of biofilm formation by the method of Congo Red Agar. The results of this genotypic and phenotypic examination were then tested for correlation with statistical tests using SPSS 23.0. A total of 40 S. epidermidis isolates were collected, consisting of 20 clinical isolates and 20 isolates of normal flora. The icaA gene was positive in 5 isolates (12.5%), and 8 isolates (20%) were positive for the icaD gene, 3 isolates with icaA and icaD were both positive. One hundred percent of isolates with icaA or icaD positively formed biofilms, but there were 15 isolates (42.9%) who did not have the icaA gene but showed the ability to form biofilms, while 12 isolates (37.5%) who did not have the icaD gene also formed biofilms. Fifty percent of S. epidermidis isolates showed the ability to form biofilms at CRA. The Fisher Exact test showed a significant relationship between the icaA gene and the ability of biofilm formation (p=0.047 (p<0.05)) as well as the icaD gene (p=0.03 (p<0.05)). The icaA and icaD genes have a significant relationship to biofilm formation in S. epidermidis. There was another mechanism in the formation of biofilms that are not dependent on the ica gene.
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26
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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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27
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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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28
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Gangwar B, Kumar S, Darokar MP. Glabridin Averts Biofilms Formation in Methicillin-Resistant Staphylococcus aureus by Modulation of the Surfaceome. Front Microbiol 2020; 11:1779. [PMID: 33071991 PMCID: PMC7534511 DOI: 10.3389/fmicb.2020.01779] [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: 04/27/2020] [Accepted: 07/07/2020] [Indexed: 12/04/2022] Open
Abstract
Staphylococcus aureus is an opportunistic bacterium of the human body and a leading cause of nosocomial infections. Methicillin resistant S. aureus (MRSA) infections involving biofilm lead to higher mortality and morbidity in patients. Biofilm causes serious clinical issues, as it mitigates entry of antimicrobials to reach the etiological agents. It plays an important role in resilient chronic infections which place an unnecessary burden on antibiotics and the associated costs. To combat drug-resistant infection involving biofilm, there is a need to discover potential anti-biofilm agents. In this study, activity of polyphenolic flavonoid glabridin against biofilm formation of methicillin resistant clinical isolates of S. aureus is being reported for the first time. Crystal violet assay and scanning electron microscopy evidences shows that glabridin prevents formation of cells clusters and attachment of methicillin resistant clinical isolate (MRSA 4423) of S. aureus to the surface in a dose dependent manner. Gel free proteomic analysis of biofilm matrix by LC-ESI-QTOF confirmed the existence of several proteins known to be involved in cells adhesion. Furthermore, expression analysis of cell surface proteins revealed that glabridin significantly down regulates an abundance of several surface-associated adhesins including fibronectin binding proteins (FnbA, FnbB), serine-aspartate repeat-containing protein D (SdrD), immunoglobulin-binding protein G (Sbi), and other virulence factors which were induced by extracellular glucose in MRSA 4423. In addition, several moonlighting proteins (proteins with multiple functions) such as translation elongation factors (EF-Tu, EF-G), chaperone protein (DnaK), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and pyruvate kinase (PK) were detected on the cell surface wherein their abundance was inversely proportional to surface-associated adhesins. This study clearly suggests that glabridin prevents biofilm formation in S. aureus through modulation of the cell surface proteins.
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Affiliation(s)
- Bhavana Gangwar
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Santosh Kumar
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India.,Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, United States
| | - Mahendra P Darokar
- Molecular Bioprospection Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
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29
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Fernández L, Gutiérrez D, García P, Rodríguez A. Environmental pH is a key modulator of Staphylococcus aureus biofilm development under predation by the virulent phage phiIPLA-RODI. ISME JOURNAL 2020; 15:245-259. [PMID: 32963343 DOI: 10.1038/s41396-020-00778-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 09/03/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022]
Abstract
Previous work had shown that, in some Staphylococcus aureus strains, low concentrations of the virulent phage vB_SauM_phiIPLA-RODI (phiIPLA-RODI) promoted the formation of DNA-rich biofilms, whose cells exhibited significant transcriptional differences compared to an uninfected control. This study aimed to dissect the sequence of events leading to these changes. Analysis of phage propagation throughout biofilm development revealed that the number of phage particles increased steadily up to a certain point and then declined. This partial phage inactivation seemed to be a consequence of medium acidification due to glucose fermentation by the bacterium. Computer simulation of phage-host dynamics during biofilm development showed how even small differences in pH evolution can affect the outcome of phage infection. An acidic pH, together with successful phage propagation, was also necessary to observe the phage-associated changes in biofilm architecture and in the transcriptional profile of the bacterial population. Altogether, this study shows how the dynamics between phage and host can be tightly coordinated through an environmental cue, even in the context of a complex biofilm population.
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Affiliation(s)
- Lucía Fernández
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n, 33300, Villaviciosa, Asturias, Spain. .,DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
| | - Diana Gutiérrez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n, 33300, Villaviciosa, Asturias, Spain.,Laboratory of Applied Biotechnology, Department of Applied Biosciences, Faculty of Bioscience engineering, Ghent University, 9000, Ghent, Belgium
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n, 33300, Villaviciosa, Asturias, Spain.,DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Ana Rodríguez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n, 33300, Villaviciosa, Asturias, Spain.,DairySafe Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
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30
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Dutta K, Karmakar A, Jana D, Ballav S, Shityakov S, Panda AK, Ghosh C. Benzyl isocyanate isolated from the leaves of Psidium guajava inhibits Staphylococcus aureus biofilm formation. BIOFOULING 2020; 36:1000-1017. [PMID: 33172298 DOI: 10.1080/08927014.2020.1842877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 09/03/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Benzyl isocyanate (BIC), from methanol extract of Psidium guajava leaves, exhibited substantial anti-biofilm activities against Staphylococcus aureus, the common bacterial pathogen in nosocomial infections. Major components of the extract included eugenol, BIC, phenyl-2-methoxy-4-(1-propenyl)-acetate and 2,5-pyrrolidinedione,1-penta-3-4-dienyl, analyzed by GC-MS and HPLC studies. BIC exhibited substantial anti-biofilm activitiy against S. aureus, established by assaying biofilm formation, biofilm metabolic activity, bacterial adherence to hydrocarbons, exopolysaccharide formation, and optical and scanning electron microscopic studies. BIC significantly downregulated the important biofilm markers of S. aureus, viz., icaAD, sarA and agr, observed by quantitative real time polymerase chain reaction analysis. Molecular docking studies revealed thermodynamically favorable interaction of BIC with IcaA, SarA and Agr, having Gibbs energy values of -8.45, -9.09 and -10.29 kcal mol-1, respectively. BIC after binding to IcaR, the repressor of IcaA, influences its binding to target DNA site (Eshape, -157.27 kcal mol-1). The results are considered to demonstrate anti-biofilm potential of BIC against bacterial infections.
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Affiliation(s)
- Kunal Dutta
- Department of Human Physiology, Vidyasagar University, Midnapore, West Bengal, India
| | - Amit Karmakar
- Department of Human Physiology, Vidyasagar University, Midnapore, West Bengal, India
| | - Debarati Jana
- Department of Human Physiology, Vidyasagar University, Midnapore, West Bengal, India
| | - Saroj Ballav
- Department of Human Physiology, Vidyasagar University, Midnapore, West Bengal, India
| | - Sergey Shityakov
- Department of Anaesthesia and Critical Care, University of Würzburg, Würzburg, Germany
| | - Amiya Kumar Panda
- Department of Chemistry, Vidyasagar University, Midnapore, West Bengal, India
| | - Chandradipa Ghosh
- Department of Human Physiology, Vidyasagar University, Midnapore, West Bengal, India
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31
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Ouyang Z, Zheng F, Chew JY, Pei Y, Zhou J, Wen K, Han M, Lemieux MJ, Hwang PM, Wen Y. Deciphering the activation and recognition mechanisms of Staphylococcus aureus response regulator ArlR. Nucleic Acids Res 2020; 47:11418-11429. [PMID: 31598698 PMCID: PMC6868441 DOI: 10.1093/nar/gkz891] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 09/21/2019] [Accepted: 10/01/2019] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus ArlRS is a key two-component regulatory system necessary for adhesion, biofilm formation, and virulence. The response regulator ArlR consists of a C-terminal DNA-binding effector domain and an N-terminal receiver domain that is phosphorylated by ArlS, the cognate transmembrane sensor histidine kinase. We demonstrate that the receiver domain of ArlR adopts the canonical α5β5 response regulator assembly, which dimerizes upon activation, using beryllium trifluoride as an aspartate phosphorylation mimic. Activated ArlR recognizes a 20-bp imperfect inverted repeat sequence in the ica operon, which is involved in intercellular adhesion polysaccharide production. Crystal structures of the inactive and activated forms reveal that activation induces a significant conformational change in the β4-α4 and β5-α5-connecting loops, in which the α4 and α5 helices constitute the homodimerization interface. Crystal structures of the DNA-binding ArlR effector domain indicate that it is able to dimerize via a non-canonical β1–β2 hairpin domain swapping, raising the possibility of a new mechanism for signal transduction from the receiver domain to effector domain. Taken together, the current study provides structural insights into the activation of ArlR and its recognition, adding to the diversity of response regulation mechanisms that may inspire novel antimicrobial strategies specifically targeting Staphylococcus.
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Affiliation(s)
- Zhenlin Ouyang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China.,Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Fang Zheng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Jared Y Chew
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Yingmei Pei
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Jinhong Zhou
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Keqing Wen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Miao Han
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - M Joanne Lemieux
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Peter M Hwang
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Yurong Wen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China.,Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China.,Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
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Catalan-Moreno A, Caballero CJ, Irurzun N, Cuesta S, López-Sagaseta J, Toledo-Arana A. One evolutionarily selected amino acid variation is sufficient to provide functional specificity in the cold shock protein paralogs of Staphylococcus aureus. Mol Microbiol 2020; 113:826-840. [PMID: 31876031 PMCID: PMC7216892 DOI: 10.1111/mmi.14446] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/11/2019] [Accepted: 12/19/2019] [Indexed: 01/12/2023]
Abstract
Bacterial genomes encode several families of protein paralogs. Discrimination between functional divergence and redundancy among paralogs is challenging due to their sequence conservation. Here, we investigated whether the amino acid differences present in the cold shock protein (CSP) paralogs of Staphylococcus aureus were responsible for functional specificity. Since deletion of cspA reduces the synthesis of staphyloxanthin (STX), we used it as an in vivo reporter of CSP functionality. Complementation of a ΔcspA strain with the different S. aureus CSP variants showed that only CspA could specifically restore STX production by controlling the activity of the stress‐associated sigma B factor (σB). To determine the amino acid residues responsible for CspA specificity, we created several chimeric CSPs that interchanged the amino acid differences between CspA and CspC, which shared the highest identity. We demonstrated that CspA Pro58 was responsible for the specific control of σB activity and its associated phenotypes. Interestingly, CspC gained the biological function of CspA when the E58P substitution was introduced. This study highlights how just one evolutionarily selected amino acid change may be sufficient to modify the specific functionality of CSP paralogs.
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Affiliation(s)
| | - Carlos J Caballero
- Instituto de Agrobiotecnología (IDAB), CSIC-UPNA-Gobierno de Navarra, Mutilva, Spain
| | - Naiara Irurzun
- Instituto de Agrobiotecnología (IDAB), CSIC-UPNA-Gobierno de Navarra, Mutilva, Spain
| | - Sergio Cuesta
- Instituto de Agrobiotecnología (IDAB), CSIC-UPNA-Gobierno de Navarra, Mutilva, Spain
| | - Jacinto López-Sagaseta
- Laboratory of Protein Crystallography, Navarrabiomed, Complejo Hospitalario de Navarra (CHN)-Universidad Pública de Navarra (UPNA), Pamplona, Spain
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Crosby HA, Tiwari N, Kwiecinski JM, Xu Z, Dykstra A, Jenul C, Fuentes EJ, Horswill AR. The Staphylococcus aureus ArlRS two-component system regulates virulence factor expression through MgrA. Mol Microbiol 2020; 113:103-122. [PMID: 31618469 PMCID: PMC7175635 DOI: 10.1111/mmi.14404] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Gram-positive bacterium, Staphylococcus aureus, is a versatile pathogen that can sense and adapt to a wide variety of environments within the human host, in part through its 16 two-component regulatory systems. The ArlRS two-component system has been shown to affect many cellular processes in S. aureus, including autolysis, biofilm formation, capsule synthesis and virulence. Yet the molecular details of this regulation remained largely unknown. We used RNA sequencing to identify the ArlRS regulon, and found 70% overlap with that of the global regulator MgrA. These genes included cell wall-anchored adhesins (ebh, sdrD), polysaccharide and capsule synthesis genes, cell wall remodeling genes (lytN, ddh), the urease operon, genes involved in metal transport (feoA, mntH, sirA), anaerobic metabolism genes (adhE, pflA, nrdDG) and a large number of virulence factors (lukSF, lukAB, nuc, gehB, norB, chs, scn and esxA). We show that ArlR directly activates expression of mgrA and identify a probable ArlR-binding site (TTTTCTCAT-N4 -TTTTAATAA). A highly similar sequence is also found in the spx P2 promoter, which was recently shown to be regulated by ArlRS. We also demonstrate that ArlS has kinase activity toward ArlR in vitro, although it has slower kinetics than other similar histidine kinases.
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Affiliation(s)
- Heidi A. Crosby
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Nitija Tiwari
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Jakub M. Kwiecinski
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Zhen Xu
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Allison Dykstra
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Christian Jenul
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Ernesto J Fuentes
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, CO
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Hannachi N, Habib G, Camoin-Jau L. Aspirin Effect on Staphylococcus aureus-Platelet Interactions During Infectious Endocarditis. Front Med (Lausanne) 2019; 6:217. [PMID: 31681776 PMCID: PMC6803506 DOI: 10.3389/fmed.2019.00217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/23/2019] [Indexed: 12/29/2022] Open
Abstract
Infectious endocarditis (IE) is a rare disease associated with high mortality and morbidity rate. The platelet-bacterial interaction presents the cornerstone of the development of endocardial vegetation. The epidemiology of IE has undergone profound changes between the last and the new decade, with Staphylococcus aureus becoming the main incriminated species. Despite improvements in antibiotic and surgical therapies, embolic disorders remain highly associated with IE that can be fatal. Antiplatelet drugs have been widely proposed to overcome embolic events associated with IE. This proposal has been supported by numerous in vitro, experimental, and clinical studies. However, other studies have yielded conflicting results. In this review, we focus on the effect of aspirin on the genesis of S. aureus endocarditic vegetation, as well as on the management of embolic and hemorrhagic events related to it, starting by its influence on the platelet-bacteria interaction.
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Affiliation(s)
- Nadji Hannachi
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France
| | - Gilbert Habib
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France
- Département de Cardiologie, Hôpital de la Timone, AP-HM, Marseille, France
| | - Laurence Camoin-Jau
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France
- Laboratoire d'Hématologie, Hôpital de la Timone, APHM, Marseille, France
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Yan H, Wang Q, Teng M, Li X. The DNA-binding mechanism of the TCS response regulator ArlR from Staphylococcus aureus. J Struct Biol 2019; 208:107388. [PMID: 31520693 DOI: 10.1016/j.jsb.2019.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 10/26/2022]
Abstract
ArlRS is an essential two-component system in Staphylococcus aureus that regulates the transcription of virulence factors and participate in numerous pathogenic and symbiotic processes. In this work, we identified different DNA binding properties and oligomerization states among the DNA-binding domain of ArlR (ArlRDBD) and the phosphorylated and unphosphorylated full-length ArlR. Based on a 2.5-Å resolution crystal structure of ArlRDBD and subsequent mutagenesis experiments, we confirmed the DNA-binding site of ArlR and the preferred binding sequences in the agr promoter that enables the DNA recognition process. Finally, we propose a putative transcription regulation mechanism for ArlR. This work will facilitate our understanding of the DNA binding affinity regulatory mechanism between the phosphorylated and unphosphorylated response regulator in the two-component system.
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Affiliation(s)
- Hui Yan
- Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Qing Wang
- Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Maikun Teng
- Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China.
| | - Xu Li
- Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China.
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Moyano AJ, Mas CR, Colque CA, Smania AM. Dealing with biofilms of Pseudomonas aeruginosa and Staphylococcus aureus: In vitro evaluation of a novel aerosol formulation of silver sulfadiazine. Burns 2019; 46:128-135. [PMID: 31420266 DOI: 10.1016/j.burns.2019.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 06/11/2019] [Accepted: 07/18/2019] [Indexed: 12/17/2022]
Abstract
The risk of infection of skin and soft tissue chronic wounds by gram-negative and gram-positive pathogens growing in biofilms is a major health-care concern. In this study we test a formulation of silver sulfadiazine, vitamin A and lidocaine (AF-SSD) for aerosol administration against biofilms of Pseudomonas aeruginosa and biofilms of methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains of Staphylococcus aureus. The aerosol allows the administration of AF-SSD without the direct contact with the wound and avoids contamination of the product after reiterative usage. We evaluated in vitro the anti-biofilm activity of AF-SSD by carrying out different technical approaches such as resazurin assays to measure metabolic activity/viability, crystal violet staining assays to determine biofilm biomass, counting of CFUs and live/dead staining for confocal microscopy analysis. AF-SSD clearly affected biofilm viability, biomass and structure, in the three bacterial strains tested. AF-SSD displayed a strong anti-biofilm effect, showing total bactericidal activity on biofilms of P. aeruginosa at a 400-fold dilution of the product, and after a 100-fold and 10-fold dilution for MRSA and MSSA, respectively. Considering the benefits of aerosol administration, our results support this kind of formulation as a potential improvement over conventional treatments with silver sulfadiazine.
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Affiliation(s)
- Alejandro J Moyano
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Córdoba, Argentina; CONICET, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Córdoba, Argentina.
| | - Carlos R Mas
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Córdoba, Argentina; CONICET, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Córdoba, Argentina
| | - Claudia A Colque
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Córdoba, Argentina; CONICET, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Córdoba, Argentina
| | - Andrea M Smania
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Córdoba, Argentina; CONICET, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Córdoba, Argentina.
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σ B Inhibits Poly- N-Acetylglucosamine Exopolysaccharide Synthesis and Biofilm Formation in Staphylococcus aureus. J Bacteriol 2019; 201:JB.00098-19. [PMID: 30858304 DOI: 10.1128/jb.00098-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/07/2019] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus clinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of the polysaccharide intercellular adhesin (PIA) or poly-N-acetylglucosamine (PNAG), whose synthesis is mediated by the icaADBC locus, and biofilm matrixes built of proteins (polysaccharide independent). σB is a conserved alternative sigma factor that regulates the expression of more than 100 genes in response to changes in environmental conditions. While numerous studies agree that σB is required for polysaccharide-independent biofilms, controversy persists over the role of σB in the regulation of PIA/PNAG-dependent biofilm development. Here, we show that genetically unrelated S. aureus σB-deficient strains produced stronger biofilms under both static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild-type strains. The increased accumulation of PIA/PNAG in the σB mutants correlated with a greater accumulation of the IcaC protein showed that it was not due to adjustments in icaADBC operon transcription and/or icaADBC mRNA stability. Overall, our results reveal that in the presence of active σB, the turnover of Ica proteins is accelerated, reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG-dependent biofilm formation capacity.IMPORTANCE Due to its multifaceted lifestyle, Staphylococcus aureus needs a complex regulatory network to connect environmental signals with cellular physiology. One particular transcription factor, named σB (SigB), is involved in the general stress response and the expression of virulence factors. For many years, great confusion has existed about the role of σB in the regulation of the biofilm lifestyle in S. aureus Our study demonstrated that σB is not necessary for exopolysaccharide-dependent biofilms and, even more, that S. aureus produces stronger biofilms in the absence of σB The increased accumulation of exopolysaccharide correlates with higher stability of the proteins responsible for its synthesis. The present findings reveal an additional regulatory layer to control biofilm exopolysaccharide synthesis under stress conditions.
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Dengler Haunreiter V, Boumasmoud M, Häffner N, Wipfli D, Leimer N, Rachmühl C, Kühnert D, Achermann Y, Zbinden R, Benussi S, Vulin C, Zinkernagel AS. In-host evolution of Staphylococcus epidermidis in a pacemaker-associated endocarditis resulting in increased antibiotic tolerance. Nat Commun 2019; 10:1149. [PMID: 30850614 PMCID: PMC6408453 DOI: 10.1038/s41467-019-09053-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 02/13/2019] [Indexed: 02/05/2023] Open
Abstract
Treatment failure in biofilm-associated bacterial infections is an important healthcare issue. In vitro studies and mouse models suggest that bacteria enter a slow-growing/non-growing state that results in transient tolerance to antibiotics in the absence of a specific resistance mechanism. However, little clinical confirmation of antibiotic tolerant bacteria in patients exists. In this study we investigate a Staphylococcus epidermidis pacemaker-associated endocarditis, in a patient who developed a break-through bacteremia despite taking antibiotics to which the S. epidermidis isolate is fully susceptible in vitro. Characterization of the clinical S. epidermidis isolates reveals in-host evolution over the 16-week infection period, resulting in increased antibiotic tolerance of the entire population due to a prolonged lag time until growth resumption and a reduced growth rate. Furthermore, we observe adaptation towards an increased biofilm formation capacity and genetic diversification of the S. epidermidis isolates within the patient.
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Affiliation(s)
- Vanina Dengler Haunreiter
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Mathilde Boumasmoud
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Nicola Häffner
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Dennis Wipfli
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Nadja Leimer
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 02115, Boston, MA, USA
| | - Carole Rachmühl
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
- Institute of Food, Nutrition and Health, ETH Zurich, 8092, Zurich, Switzerland
| | - Denise Kühnert
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
- Max Planck Institute for the Science of Human History, 07745, Jena, Germany
| | - Yvonne Achermann
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Reinhard Zbinden
- Institute of Medical Microbiology, University of Zurich, 8006, Zurich, Switzerland
| | - Stefano Benussi
- Department of Cardiac Surgery, University Heart Center, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Clement Vulin
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag, 8600, Dübendorf, Switzerland
| | - Annelies S Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland.
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Alves-Barroco C, Roma-Rodrigues C, Balasubramanian N, Guimarães MA, Ferreira-Carvalho BT, Muthukumaran J, Nunes D, Fortunato E, Martins R, Santos-Silva T, Figueiredo AMS, Fernandes AR, Santos-Sanches I. Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae. Int J Med Microbiol 2019; 309:169-181. [PMID: 30799091 DOI: 10.1016/j.ijmm.2019.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 02/14/2019] [Accepted: 02/17/2019] [Indexed: 01/15/2023] Open
Abstract
Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess the presence of biofilm regulatory protein BrpA homolog in the biofilm producers; and to predict a structural model of BrpA-like protein and its binding to putative inhibitors. Our results show that SDSD isolates form biofilms on abiotic surface such as glass (hydrophilic) and polystyrene (hydrophobic), with the strongest biofilm formation observed in glass. This ability was mainly associated with a proteinaceous extracellular matrix, confirmed by the dispersion of the biofilms after proteinase K and trypsin treatment. The biofilm formation in SDSD isolates was also confirmed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Under SEM observation, VSD16 isolate formed cell aggregates during biofilm growth while VSD9 and VSD10 formed smooth and filmy layers. We show that brpA-like gene is present and expressed in SDSD biofilm-producing isolates and its expression levels correlated with the biofilm production capability, being more expressed in the late exponential phase of planktonic growth compared to biofilm growth. Fisetin, a known biofilm inhibitor and a putative BrpA binding molecule, dramatically inhibited biofilm formation by the SDSD isolates but did not affect planktonic growth, at the tested concentrations. Homology modeling was used to predict the 3D structure of BrpA-like protein. Using high throughput virtual screening and molecular docking, we selected five ligand molecules with strong binding affinity to the hydrophobic cleft of the protein, making them potential inhibitor candidates of the SDSD BrpA-like protein. These results warrant further investigations for developing novel strategies for SDSD anti-biofilm therapy.
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Affiliation(s)
- Cinthia Alves-Barroco
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Catarina Roma-Rodrigues
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Natesan Balasubramanian
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal; Department of Immunology, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625021, India
| | | | | | - Jayaraman Muthukumaran
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Daniela Nunes
- i3N/CENIMAT, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Elvira Fortunato
- i3N/CENIMAT, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Rodrigo Martins
- i3N/CENIMAT, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Teresa Santos-Silva
- UCIBIO, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
| | - Agnes M S Figueiredo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, RJ, Brazil.
| | - Alexandra R Fernandes
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
| | - Ilda Santos-Sanches
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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The peptidoglycan and biofilm matrix of Staphylococcus epidermidis undergo structural changes when exposed to human platelets. PLoS One 2019; 14:e0211132. [PMID: 30682094 PMCID: PMC6347161 DOI: 10.1371/journal.pone.0211132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 01/02/2019] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus epidermidis is a bacterium frequently isolated from contaminated platelet concentrates (PCs), a blood product used to treat bleeding disorders in transfusion patients. PCs offer an accidental niche for colonization of S. epidermidis by forming biofilms and thus avoiding clearance by immune factors present in this milieu. Using biochemical and microscopy techniques, we investigated the structural changes of the peptidoglycan (PG) and the biofilm matrix of S. epidermidis biofilms formed in whole-blood derived PCs compared to biofilms grown in glucose-supplemented trypticase soy broth (TSBg). Both, the PG and the biofilm matrix are primary mechanisms of defense against environmental stress. Here we show that in PCs, the S. epidermidis biofilm matrix is mainly of a proteinaceous nature with extracellular DNA, in contrast to the predominant polysaccharide nature of the biofilm matrix formed in TSBg cultures. PG profile studies demonstrated that the PG of biofilm cells remodels during PC storage displaying fewer muropeptides variants than those observed in TSBg. The PG muropeptides contain two chemical modifications (amidation and O-acetylation) previously associated with resistance to antimicrobial agents by other staphylococci. Our study highlights two key structural features of S. epidermidis that are remodeled when exposed to human platelets and could be used as targets to reduce septic transfusions events.
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Microbiological and Cellular Evaluation of a Fluorine-Phosphorus-Doped Titanium Alloy, a Novel Antibacterial and Osteostimulatory Biomaterial with Potential Applications in Orthopedic Surgery. Appl Environ Microbiol 2019; 85:AEM.02271-18. [PMID: 30367003 DOI: 10.1128/aem.02271-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/09/2018] [Indexed: 02/08/2023] Open
Abstract
Joint prosthesis failure is mainly related to aseptic loosening and prosthetic joint infections, both of which are associated with high morbidity and substantial costs for patients and health systems. The development of a biomaterial that is capable of stimulating bone growth while minimizing bacterial adhesion would reduce the incidence of prosthetic failure. We report antibacterial and osteostimulatory effects in a novel fluorine-phosphorus (F-P)-doped TiO2 oxide film grown on Ti-6Al-4V alloy with a nanostructure of bottle-shaped nanotubes (bNT) using five bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia) and MCT3T3-E1 osteoblastic cells. The interaction between the bacteria and bNT Ti-6Al-4V was complex, as the adhesion of four bacterial species decreased (two staphylococcus species, E. coli, and S. maltophilia), and the viability of staphylococci and S. maltophilia also decreased because of the aluminum (Al) released by bNT Ti-6Al-4V. This released Al can be recruited by the bacteria through siderophores and was retained only by the Gram-negative bacteria tested. P. aeruginosa showed higher adhesion on bNT Ti-6Al-4V than on chemically polished (CP) samples of Ti-6Al-4V alloy and an ability to mobilize Al from bNT Ti-6Al-4V. The cell adhesion and proliferation of MCT3T3-E1 osteoblastic cells significantly increased at 48 and 168 h, as did the matrix mineralization of these cells and the gene expression levels of three of the most important markers related to bone differentiation. According to our results, the bNT Ti-6Al-4V alloy could have clinical application, preventing infection and stimulating bone growth and thus preventing the two main causes of joint prosthesis failure.IMPORTANCE This work evaluates F-P-doped bNT Ti-6Al-4V from microbiological and cellular approaches. The bacterial results highlight that the antibacterial ability of bNT Ti-6Al-4V is the result of a combination of antiadhesive and bactericidal effects exerted by Al released from the alloy. The cell results highlight that F-P bNT Ti-6Al-4V alloy increases osseointegration due to modification of the chemical composition of the alloy resulting from P incorporation and not due to the nanostructure, as reported previously. A key finding was the detection of Al release from inside the bNT Ti-6Al-4V nanostructures, a result of the nanostructure growth during the anodizing process that is in part responsible for its bactericidal effect.
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Suresh MK, Biswas R, Biswas L. An update on recent developments in the prevention and treatment of Staphylococcus aureus biofilms. Int J Med Microbiol 2019; 309:1-12. [DOI: 10.1016/j.ijmm.2018.11.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/17/2022] Open
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Matrix Polysaccharides and SiaD Diguanylate Cyclase Alter Community Structure and Competitiveness of Pseudomonas aeruginosa during Dual-Species Biofilm Development with Staphylococcus aureus. mBio 2018; 9:mBio.00585-18. [PMID: 30401769 PMCID: PMC6222129 DOI: 10.1128/mbio.00585-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bacteria in natural and engineered environments form biofilms that include many different species. Microorganisms rely on a number of different strategies to manage social interactions with other species and to access resources, build biofilm consortia, and optimize growth. For example, Pseudomonas aeruginosa and Staphylococcus aureus are biofilm-forming bacteria that coinfect the lungs of cystic fibrosis patients and diabetic and chronic wounds. P. aeruginosa is known to antagonize S. aureus growth. However, many of the factors responsible for mixed-species interactions and outcomes such as infections are poorly understood. Biofilm bacteria are encased in a self-produced extracellular matrix that facilitates interspecies behavior and biofilm development. In this study, we examined the poorly understood roles of the major matrix biopolymers and their regulators in mixed-species biofilm interactions and development. Mixed-species biofilms display a number of emergent properties, including enhanced antimicrobial tolerance and communal metabolism. These properties may depend on interspecies relationships and the structure of the biofilm. However, the contribution of specific matrix components to emergent properties of mixed-species biofilms remains poorly understood. Using a dual-species biofilm community formed by the opportunistic pathogens Pseudomonas aeruginosa and Staphylococcus aureus, we found that whilst neither Pel nor Psl polysaccharides, produced by P. aeruginosa, affect relative species abundance in mature P. aeruginosa and S. aureus biofilms, Psl production is associated with increased P. aeruginosa abundance and reduced S. aureus aggregation in the early stages of biofilm formation. Our data suggest that the competitive effect of Psl is not associated with its structural role in cross-linking the matrix and adhering to P. aeruginosa cells but is instead mediated through the activation of the diguanylate cyclase SiaD. This regulatory control was also found to be independent of the siderophore pyoverdine and Pseudomonas quinolone signal, which have previously been proposed to reduce S. aureus viability by inducing lactic acid fermentation-based growth. In contrast to the effect mediated by Psl, Pel reduced the effective crosslinking of the biofilm matrix and facilitated superdiffusivity in microcolony regions. These changes in matrix cross-linking enhance biofilm surface spreading and expansion of microcolonies in the later stages of biofilm development, improving overall dual-species biofilm growth and increasing biovolume severalfold. Thus, the biofilm matrix and regulators associated with matrix production play essential roles in mixed-species biofilm interactions.
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González S, Fernández L, Gutiérrez D, Campelo AB, Rodríguez A, García P. Analysis of Different Parameters Affecting Diffusion, Propagation and Survival of Staphylophages in Bacterial Biofilms. Front Microbiol 2018; 9:2348. [PMID: 30323804 PMCID: PMC6172340 DOI: 10.3389/fmicb.2018.02348] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/12/2018] [Indexed: 02/04/2023] Open
Abstract
The elimination of bacterial biofilms remains a major challenge due to their recalcitrant nature. Bacteriophages, viruses that infect bacteria, have been gaining increasing attention as biofilm control agents. However, the development of a successful phage-based strategy requires in-depth analysis of different parameters. It is particularly important to determine the ability of a given phage to diffuse, propagate and remain viable within the complex biofilm structure. Here, we examine some of these properties for two staphylophages, vB_SauM_phiIPLA-RODI and vB_SepM_phiIPLA-C1C. Both Staphylococcus aureus and Staphylococcus epidermidis are important opportunistic pathogens that readily form biofilms on a wide array of biotic and abiotic surfaces. Our results confirmed that both phages could penetrate through biofilms formed by several bacterial strains with varying degrees of susceptibility to the viruses and biofilm-forming abilities. However, phage penetration differed depending on the specific bacterium or combination of bacteria. The data presented here suggest that the factors determining the diffusion rate of phages in biofilms include the amount of attached biomass, susceptibility of the strain, initial phage titer, phage entrapment in the extracellular matrix, and phage inactivation. This information will help to further characterize phage-bacteria interactions within biofilm communities and will be valuable for the development of antistaphylococcal products based on these phages.
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Affiliation(s)
- Silvia González
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
| | - Lucía Fernández
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
| | - Diana Gutiérrez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
| | - Ana Belén Campelo
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
| | - Ana Rodríguez
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
| | - Pilar García
- Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
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MgrA Negatively Regulates Biofilm Formation and Detachment by Repressing the Expression of psm Operons in Staphylococcus aureus. Appl Environ Microbiol 2018. [PMID: 29884758 DOI: 10.1128/aem01008-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Phenol-soluble modulins (PSMs) are amphipathic peptides that are produced by staphylococci and play important roles in Staphylococcus aureus biofilm formation and dissemination. Although the multiple functions of PSMs have been recognized, the regulatory mechanisms controlling the expression of psm operons remain largely unknown. In this study, we identified MgrA in a DNA pulldown assay and further demonstrated, by electrophoretic mobility shift assays and DNase I footprinting assays, that MgrA could bind specifically to the promoter regions of psm operons. We then constructed an isogenic mgrA deletion strain and compared biofilm formation and detachment in the wild-type and isogenic mgrA deletion strains. Our results indicated that biofilm formation and detachment were significantly increased in the mgrA mutant strain. Real-time quantitative reverse transcription-PCR data indicated that MgrA repressed the transcription of psm operons in cultures and biofilms, suggesting that MgrA is a negative regulator of psm expression. Furthermore, we analyzed biofilm formation by the psm mutant strains, and we found that PSMs promoted biofilm structuring and development in the mgrA mutant strain. These findings reveal that MgrA negatively regulates biofilm formation and detachment by repressing the expression of psm operons through direct binding to the psm promoter regions.IMPORTANCEStaphylococcus aureus is a human and animal pathogen that can cause biofilm-associated infections. PSMs have multiple functions in biofilm development and virulence in staphylococcal pathogenesis. This study has revealed that MgrA can negatively regulate psm expression by binding directly to the promoter regions of psm operons. Furthermore, our results show that MgrA can modulate biofilm structuring and development by repressing the production of PSMs in S. aureus Our findings provide novel insights into the regulatory mechanisms of S. aureus psm gene expression, biofilm development, and pathogenesis.
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MgrA Negatively Regulates Biofilm Formation and Detachment by Repressing the Expression of psm Operons in Staphylococcus aureus. Appl Environ Microbiol 2018; 84:AEM.01008-18. [PMID: 29884758 PMCID: PMC6070752 DOI: 10.1128/aem.01008-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/03/2018] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus is a human and animal pathogen that can cause biofilm-associated infections. PSMs have multiple functions in biofilm development and virulence in staphylococcal pathogenesis. This study has revealed that MgrA can negatively regulate psm expression by binding directly to the promoter regions of psm operons. Furthermore, our results show that MgrA can modulate biofilm structuring and development by repressing the production of PSMs in S. aureus. Our findings provide novel insights into the regulatory mechanisms of S. aureus psm gene expression, biofilm development, and pathogenesis. Phenol-soluble modulins (PSMs) are amphipathic peptides that are produced by staphylococci and play important roles in Staphylococcus aureus biofilm formation and dissemination. Although the multiple functions of PSMs have been recognized, the regulatory mechanisms controlling the expression of psm operons remain largely unknown. In this study, we identified MgrA in a DNA pulldown assay and further demonstrated, by electrophoretic mobility shift assays and DNase I footprinting assays, that MgrA could bind specifically to the promoter regions of psm operons. We then constructed an isogenic mgrA deletion strain and compared biofilm formation and detachment in the wild-type and isogenic mgrA deletion strains. Our results indicated that biofilm formation and detachment were significantly increased in the mgrA mutant strain. Real-time quantitative reverse transcription-PCR data indicated that MgrA repressed the transcription of psm operons in cultures and biofilms, suggesting that MgrA is a negative regulator of psm expression. Furthermore, we analyzed biofilm formation by the psm mutant strains, and we found that PSMs promoted biofilm structuring and development in the mgrA mutant strain. These findings reveal that MgrA negatively regulates biofilm formation and detachment by repressing the expression of psm operons through direct binding to the psm promoter regions. IMPORTANCEStaphylococcus aureus is a human and animal pathogen that can cause biofilm-associated infections. PSMs have multiple functions in biofilm development and virulence in staphylococcal pathogenesis. This study has revealed that MgrA can negatively regulate psm expression by binding directly to the promoter regions of psm operons. Furthermore, our results show that MgrA can modulate biofilm structuring and development by repressing the production of PSMs in S. aureus. Our findings provide novel insights into the regulatory mechanisms of S. aureus psm gene expression, biofilm development, and pathogenesis.
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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Poupel O, Proux C, Jagla B, Msadek T, Dubrac S. SpdC, a novel virulence factor, controls histidine kinase activity in Staphylococcus aureus. PLoS Pathog 2018; 14:e1006917. [PMID: 29543889 PMCID: PMC5854430 DOI: 10.1371/journal.ppat.1006917] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 02/01/2018] [Indexed: 11/18/2022] Open
Abstract
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop. The WalKR system is mainly involved in controlling cell wall metabolism through regulation of autolysin production. We have shown that SpdC inhibits the WalKR-dependent synthesis of four peptidoglycan hydrolases, SceD, SsaA, LytM and AtlA, as well as impacting S. aureus resistance towards lysostaphin and cell wall antibiotics such as oxacillin and tunicamycin. We have also shown that SpdC is required for S. aureus biofilm formation and virulence in a murine septicemia model. Using protein-protein interactions in E. coli as well as subcellular localization in S. aureus, we showed that SpdC and the WalK kinase are both localized at the division septum and that the two proteins interact. In addition to WalK, our results indicate that SpdC also interacts with nine other S. aureus histidine kinases, suggesting that this membrane protein may act as a global regulator of TCS activity. Indeed, using RNA-Seq analysis, we showed that SpdC controls the expression of approximately one hundred genes in S. aureus, many of which belong to TCS regulons.
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Affiliation(s)
- Olivier Poupel
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
| | - Caroline Proux
- Transcriptome and EpiGenome, BioMics, Center for Innovation and Technological Research, Institut Pasteur, Paris, France
| | - Bernd Jagla
- Transcriptome and EpiGenome, BioMics, Center for Innovation and Technological Research, Institut Pasteur, Paris, France
- Center for Human Immunology, Center for Translational Science, Institut Pasteur, Paris, France
- Bioinformatics & Biostatistics HUB, Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris, France
| | - Tarek Msadek
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
- * E-mail: (TM); (SD)
| | - Sarah Dubrac
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
- * E-mail: (TM); (SD)
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Burgui S, Gil C, Solano C, Lasa I, Valle J. A Systematic Evaluation of the Two-Component Systems Network Reveals That ArlRS Is a Key Regulator of Catheter Colonization by Staphylococcus aureus. Front Microbiol 2018; 9:342. [PMID: 29563900 PMCID: PMC5845881 DOI: 10.3389/fmicb.2018.00342] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/12/2018] [Indexed: 12/29/2022] Open
Abstract
Two-component systems (TCS) are modular signal transduction pathways that allow cells to adapt to prevailing environmental conditions by modifying cellular physiology. Staphylococcus aureus has 16 TCSs to adapt to the diverse microenvironments encountered during its life cycle, including host tissues and implanted medical devices. S. aureus is particularly prone to cause infections associated to medical devices, whose surfaces coated by serum proteins constitute a particular environment. Identification of the TCSs involved in the adaptation of S. aureus to colonize and survive on the surface of implanted devices remains largely unexplored. Here, using an in vivo catheter infection model and a collection of mutants in each non-essential TCS of S. aureus, we investigated the requirement of each TCS for colonizing the implanted catheter. Among the 15 mutants in non-essential TCSs, the arl mutant exhibited the strongest deficiency in the capacity to colonize implanted catheters. Moreover, the arl mutant was the only one presenting a major deficit in PNAG production, the main exopolysaccharide of the S. aureus biofilm matrix whose synthesis is mediated by the icaADBC locus. Regulation of PNAG synthesis by ArlRS occurred through repression of IcaR, a transcriptional repressor of icaADBC operon expression. Deficiency in catheter colonization was restored when the arl mutant was complemented with the icaADBC operon. MgrA, a global transcriptional regulator downstream ArlRS that accounts for a large part of the arlRS regulon, was unable to restore PNAG expression and catheter colonization deficiency of the arlRS mutant. These findings indicate that ArlRS is the key TCS to biofilm formation on the surface of implanted catheters and that activation of PNAG exopolysaccharide production is, among the many traits controlled by the ArlRS system, a major contributor to catheter colonization.
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Affiliation(s)
- Saioa Burgui
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Carmen Gil
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Jaione Valle
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
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Abstract
Bacteria use two-component systems (TCSs) to sense and respond to environmental changes. The core genome of the major human pathogen Staphylococcus aureus encodes 16 TCSs, one of which (WalRK) is essential. Here we show that S. aureus can be deprived of its complete sensorial TCS network and still survive under growth arrest conditions similarly to wild-type bacteria. Under replicating conditions, however, the WalRK system is necessary and sufficient to maintain bacterial growth, indicating that sensing through TCSs is mostly dispensable for living under constant environmental conditions. Characterization of S. aureus derivatives containing individual TCSs reveals that each TCS appears to be autonomous and self-sufficient to sense and respond to specific environmental cues, although some level of cross-regulation between non-cognate sensor-response regulator pairs occurs in vivo. This organization, if confirmed in other bacterial species, may provide a general evolutionarily mechanism for flexible bacterial adaptation to life in new niches.
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