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Belluzo BS, Abriata LA, Giannini E, Mihovilcevic D, Dal Peraro M, Llarrull LI. An experiment-informed signal transduction model for the role of the Staphylococcus aureus MecR1 protein in β-lactam resistance. Sci Rep 2019; 9:19558. [PMID: 31862951 PMCID: PMC6925264 DOI: 10.1038/s41598-019-55923-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 12/04/2019] [Indexed: 11/13/2022] Open
Abstract
The treatment of hospital- and community-associated infections by methicillin-resistant Staphylococcus aureus (MRSA) is a perpetual challenge. This Gram-positive bacterium is resistant specifically to β-lactam antibiotics, and generally to many other antibacterial agents. Its resistance mechanisms to β-lactam antibiotics are activated only when the bacterium encounters a β-lactam. This activation is regulated by the transmembrane sensor/signal transducer proteins BlaR1 and MecR1. Neither the transmembrane/metalloprotease domain, nor the complete MecR1 and BlaR1 proteins, are isolatable for mechanistic study. Here we propose a model for full-length MecR1 based on homology modeling, residue coevolution data, a new extensive experimental mapping of transmembrane topology, partial structures, molecular simulations, and available NMR data. Our model defines the metalloprotease domain as a hydrophilic transmembrane chamber effectively sealed by the apo-sensor domain. It proposes that the amphipathic helices inserted into the gluzincin domain constitute the route for transmission of the β-lactam-binding event in the extracellular sensor domain, to the intracellular and membrane-embedded zinc-containing active site. From here, we discuss possible routes for subsequent activation of proteolytic action. This study provides the first coherent model of the structure of MecR1, opening routes for future functional investigations on how β-lactam binding culminates in the proteolytic degradation of MecI.
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Affiliation(s)
- Bruno S Belluzo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - Luciano A Abriata
- Laboratory for Biomolecular Modeling - École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, CH-1015, Lausanne, Switzerland
| | - Estefanía Giannini
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - Damila Mihovilcevic
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - Matteo Dal Peraro
- Laboratory for Biomolecular Modeling - École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, CH-1015, Lausanne, Switzerland
| | - Leticia I Llarrull
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Predio CONICET Rosario, 27 de Febrero 210 bis, 2000, Rosario, Argentina. .,Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 570, 2000, Rosario, Argentina.
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Adetutu AA, Oritsewehinmi B, Ikhiwili OM, Moradeke AO, Odochi AS, Adeola OE. Studies on Staphylococcus aureus Isolated from Pimples. Pak J Biol Sci 2017; 20:350-354. [PMID: 29023067 DOI: 10.3923/pjbs.2017.350.354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Pimples (acne) are small skin lesions or inflammations of the skin. The most common factor causing acne is the hormonal changes that occur during adolescent and teenage years. Antibiotics are becoming less effective in the treatment of pimples due to increasing concerns of antibiotic resistance. This study was therefore carried out to characterize the isolates from the pimples of Covenant University Students and to determine their antibiotics sensitivity pattern. MATERIALS AND METHODS A total of 20 swab samples were obtained from male and female students with obvious signs of pimples in Covenant University, Ota, Ogun State, Nigeria. The samples obtained were cultured on Mannitol Salt Agar and incubated at 37°C. Pure isolates obtained were subjected to Gram staining and other biochemical tests for identification. The isolates were further subjected to antibiotics sensitivity tests using antibiotic dics. RESULTS Macroscopic examination indicated that the organisms were convex, smooth and shiny. Microscopic examination revealed that the isolates were positive after employing the Gram Staining technique and they appeared as grape-like clusters. Biochemical tests revealed that the isolates were Coagulase positive, Catalase positive, Urease positive, Citrate positive, Methyl-Red positive, Voges-Proskauer negative and negative upon starch hydrolysis. The sugar fermentation tests revealed that the isolates fermented Glucose, Maltose, Galactose, Sucrose and Lactose, respectively. The antibiotic susceptibility test showed that isolates were resistant to Cotrimazole, Cloxacillin, Erythromycin, Gentamycin, Augmentin, Streptomycin, Tetracycline and Chloramphenicol. CONCLUSION The results therefore indicated that the isolates were Staphylococcus aureus and other staphylococci species. Indiscriminate use of antibiotics should be avoided to prevent the development of resistant strains of the Staphylococci genera and other pathogenic organisms.
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Affiliation(s)
| | - Bibi Oritsewehinmi
- Department of Biological Sciences, University of Covenant, Ota, PMB 1023, Nigeria
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Date SV, Modrusan Z, Lawrence M, Morisaki JH, Toy K, Shah IM, Kim J, Park S, Xu M, Basuino L, Chan L, Zeitschel D, Chambers HF, Tan MW, Brown EJ, Diep BA, Hazenbos WLW. Global gene expression of methicillin-resistant Staphylococcus aureus USA300 during human and mouse infection. J Infect Dis 2013; 209:1542-50. [PMID: 24286981 DOI: 10.1093/infdis/jit668] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Little is known about the expression of methicillin-resistant Staphylococcus aureus (MRSA) genes during infection conditions. Here, we described the transcriptome of the clinical MRSA strain USA300 derived from human cutaneous abscesses, and compared it with USA300 bacteria derived from infected kidneys in a mouse model. Remarkable similarity between the transcriptomes allowed us to identify genes encoding multiple proteases and toxins, and iron- and peptide-transporter molecules, which are upregulated in both infections and are likely important for establishment of infection. We also showed that disruption of the global transcriptional regulators agr and sae prevents in vivo upregulation of many toxins and proteases, protecting mice from lethal infection dose, and hinting at the role of these transcriptional regulators in the pathology of MRSA infection.
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Llarrull LI, Mobashery S. Dissection of events in the resistance to β-lactam antibiotics mediated by the protein BlaR1 from Staphylococcus aureus. Biochemistry 2012; 51:4642-9. [PMID: 22616850 DOI: 10.1021/bi300429p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A heterologous expression system was used to evaluate activation of BlaR1, a sensor/signal transducer protein of Staphylococcus aureus with a central role in resistance to β-lactam antibiotics. In the absence of other S. aureus proteins that might respond to antibiotics and participate in signal transduction events, we documented that BlaR1 fragmentation is autolytic, that it occurs in the absence of antibiotics, and that BlaR1 directly degrades BlaI, the gene repressor of the system. Furthermore, we disclosed that this proteolytic activity is metal ion-dependent and that it is not modulated directly by acylation of the sensor domain by β-lactam antibiotics.
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Affiliation(s)
- Leticia I Llarrull
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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Simulated antibiotic exposures in an in vitro hollow-fiber infection model influence toxin gene expression and production in community-associated methicillin-resistant Staphylococcus aureus strain MW2. Antimicrob Agents Chemother 2011; 56:140-7. [PMID: 22064533 DOI: 10.1128/aac.05113-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain MW2 harbors a plethora of toxins to mediate its virulence. However, toxin expression and regulation with simulated clinical antimicrobial exposures are unclear. This study evaluated these relationships using an in vitro pharmacodynamic hollow-fiber infection model. Clinical doses of clindamycin, linezolid, minocycline, trimethoprim-sulfamethoxazole (SXT), and vancomycin were simulated over 72 h against MW2 in the hollow fiber model. Expression levels of lukSF-PV and enterotoxin genes sec4, sek, seq, and sel2 were quantified by real-time PCR. Panton-Valentine leukocidin (PVL) was quantified by enzyme-linked immunosorbent assay (ELISA), and cytotoxicity was determined on polymorphonuclear cells (PMNs). Vancomycin produced the maximum MW2 killing (2.53 log(10) CFU/ml) after the first dose, but the greatest sustained killing over 72 h occurred with linezolid and clindamycin. Vancomycin and minocycline induced gene upregulation from 0 to 8 h, followed by downregulation for the remaining simulation period. Clindamycin decreased gene expression in the first 24 h, followed by moderate increases (2.5-fold) thereafter. Linezolid increased gene expression 11.4- to 200.4-fold but inhibited PVL production (0.6 ± 0.3 versus 5.9 ± 0.2 μg/ml, linezolid versus control at 72 h; P < 0.05). Similar effects on PVL production occurred with clindamycin and minocycline. SXT increased PVL production at 48 h (2.8-fold) and 72 h (4.9-fold) of treatment (P < 0.05), resulting in increased PVL cytotoxicity on PMNs. Linezolid, clindamycin, and minocycline were the most effective agents on decreasing the virulence potential in CA-MRSA, notably after 8 h of treatment. SXT had minimal effects on toxin gene regulation, but it increased production and cytotoxicity of PVL toxin in the model and may enhance virulence when it is used to treat severe infections.
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Bröker BM, van Belkum A. Immune proteomics of Staphylococcus aureus. Proteomics 2011; 11:3221-31. [DOI: 10.1002/pmic.201100010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 04/28/2011] [Accepted: 05/03/2011] [Indexed: 01/08/2023]
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Ganesh VK, Barbu EM, Deivanayagam CCS, Le B, Anderson AS, Matsuka YV, Lin SL, Foster TJ, Narayana SVL, Höök M. Structural and biochemical characterization of Staphylococcus aureus clumping factor B/ligand interactions. J Biol Chem 2011; 286:25963-72. [PMID: 21543319 DOI: 10.1074/jbc.m110.217414] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Clumping factor B (ClfB) from Staphylococcus aureus is a bifunctional protein that binds to human cytokeratin 10 (K10) and fibrinogen (Fg). ClfB has been implicated in S. aureus colonization of nasal epithelium and is therefore a key virulence factor. People colonized with S. aureus are at an increased risk for invasive staphylococcal disease. In this study, we have determined the crystal structures of the ligand-binding region of ClfB in an apo-form and in complex with human K10 and Fg α-chain-derived peptides, respectively. We have determined the structures of MSCRAMM binding to two ligands with different sequences in the same site showing the versatile nature of the ligand recognition mode of microbial surface components recognizing adhesive matrix molecules. Both ligands bind ClfB by parallel β-sheet complementation as observed for the clumping factor A·γ-chain peptide complex. The β-sheet complementation is shorter in the ClfB·Fg α-chain peptide complex. The structures show that several residues in ClfB are important for binding to both ligands, whereas others only make contact with one of the ligands. A common motif GSSGXG found in both ligands is part of the ClfB-binding site. This motif is found in many human proteins thus raising the possibility that ClfB recognizes additional ligands.
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Affiliation(s)
- Vannakambadi K Ganesh
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030, USA.
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Moellering RC, Abbott GF, Ferraro MJ. Case records of the Massachusetts General Hospital. Case 2-2011. A 30-year-old woman with shock after treatment of a furuncle. N Engl J Med 2011; 364:266-75. [PMID: 21247318 DOI: 10.1056/nejmcpc1003886] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Robert C Moellering
- Division of Infectious Diseases, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, USA
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Methicillin-resistant Staphylococcus aureus: related infections and antibiotic resistance. Int J Infect Dis 2010; 14 Suppl 4:S19-22. [DOI: 10.1016/j.ijid.2010.05.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Beaume M, Hernandez D, Francois P, Schrenzel J. New approaches for functional genomic studies in staphylococci. Int J Med Microbiol 2009; 300:88-97. [PMID: 20005775 DOI: 10.1016/j.ijmm.2009.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Functional transcriptomics studies have resulted in interesting insights into Staphylococcus aureus diversity and pathogenicity. Here we review the principles, advantages and disadvantages of recent technical developments in the field of transcriptomics and their potential impact on S. aureus research.
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Affiliation(s)
- Marie Beaume
- Genomic Research Laboratory, Service of Infectious Diseases, University of Geneva Hospitals (HUG), CH-1211 Geneva 14, Switzerland
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Crémieux AC, Dumitrescu O, Lina G, Vallee C, Côté JF, Muffat-Joly M, Lilin T, Etienne J, Vandenesch F, Saleh-Mghir A. Panton-valentine leukocidin enhances the severity of community-associated methicillin-resistant Staphylococcus aureus rabbit osteomyelitis. PLoS One 2009; 4:e7204. [PMID: 19779608 PMCID: PMC2744873 DOI: 10.1371/journal.pone.0007204] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 08/14/2009] [Indexed: 12/04/2022] Open
Abstract
Background Extensive spread of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in the United States, and the concomitant increase in severe invasive staphylococcal infections, including osteomyelitis, in healthy children, has led to renewed interest in Panton-Valentine leukocidin (PVL). However, the pathogenetic role of PVL in staphylococcal infections remains controversial, possibly because it depends on the site of infection. Methodology/Principal Findings We compared the course of experimental rabbit osteomyelitis due to the PVL-positive CA-MRSA strain USA 300 (LAC) and its PVL-negative isogenic derivative (LACΔpvl), using a low and a high inoculum (8×105 and 4×108 CFU). With the low inoculum, bone infection was less frequent on day 7 (D7) and day 28 (D28) with LACΔpvl than with LAC (respectively 12/19 and 18/19 animals, p = 0.042). With the high inoculum of both strains, all the animals were infected on D7 and the infection persisted on D28 in almost every case. However, tibial bacterial counts and the serum CRP concentration fell significantly between D7 and D28 with LACΔpvl but not with LAC. Respectively 67% and 60% of LAC-infected rabbits had bone deformation and muscle/joint involvement on D7, compared to 0% and 7% of LACΔpvl-infected rabbits (p = 0.001 and p = 0.005 respectively). Between D0 and D28, the anti-PVL antibody titer increased significantly only with the high inoculum of LAC. Conclusions/Significance PVL appears to play a role in the persistence and rapid local extension of rabbit osteomyelitis, in keeping with the greater severity of human bone infections due to PVL-positive S. aureus. The possible therapeutic implications of these findings are discussed.
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Affiliation(s)
- Anne-Claude Crémieux
- Département de médecine aigüe, Hôpital Universitaire Raymond Poincaré, Assistance Publique-Hôpitaux de Paris, Garches, France
- EA 3647, Faculté de Médecine Paris-Ile-de–France Ouest, Université Versailles Saint Quentin, Versailles, France
- * E-mail: (ACC); (FV)
| | - Oana Dumitrescu
- Inserm U851, Centre National de référence des Staphylocoques, Faculté Laennec, Université Lyon 1, Lyon, France
| | - Gerard Lina
- Inserm U851, Centre National de référence des Staphylocoques, Faculté Laennec, Université Lyon 1, Lyon, France
| | - Christian Vallee
- Service de radiologie, Hôpital Universitaire Raymond Poincaré, Assistance Publique-Hôpitaux de Paris, Garches, France
| | - Jean-François Côté
- Service Anatomie Pathologique, Hôpital Ambroise Paré, Boulogne-Billancourt, France
| | - Martine Muffat-Joly
- Inserm IFR2-Centre d'Explorations Fonctionnelles Intégré, UFR de Médecine Paris 7, site Bichat, Paris, France
| | - Thomas Lilin
- Centre de Recherches Biomédicales, Ecole Nationale Vétérinaire d'Alfort, Maisons Alfort, France
| | - Jerome Etienne
- Inserm U851, Centre National de référence des Staphylocoques, Faculté Laennec, Université Lyon 1, Lyon, France
| | - François Vandenesch
- Inserm U851, Centre National de référence des Staphylocoques, Faculté Laennec, Université Lyon 1, Lyon, France
- * E-mail: (ACC); (FV)
| | - Azzam Saleh-Mghir
- EA 3647, Faculté de Médecine Paris-Ile-de–France Ouest, Université Versailles Saint Quentin, Versailles, France
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Molecular basis and phenotype of methicillin resistance in Staphylococcus aureus and insights into new beta-lactams that meet the challenge. Antimicrob Agents Chemother 2009; 53:4051-63. [PMID: 19470504 DOI: 10.1128/aac.00084-09] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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