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Xiong YQ, Li Y, Goncheva MI, Elsayed AM, Zhu F, Li L, Abdelhady W, Flannagan RS, Yeaman MR, Bayer AS, Heinrichs DE. The Purine Biosynthesis Repressor, PurR, Contributes to Vancomycin Susceptibility of Methicillin-resistant Staphylococcus aureus in Experimental Endocarditis. J Infect Dis 2024; 229:1648-1657. [PMID: 38297970 PMCID: PMC11175694 DOI: 10.1093/infdis/jiad577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND Staphylococcus aureus is the most common cause of life-threatening endovascular infections, including infective endocarditis (IE). These infections, especially when caused by methicillin-resistant strains (MRSA), feature limited therapeutic options and high morbidity and mortality rates. METHODS Herein, we investigated the role of the purine biosynthesis repressor, PurR, in virulence factor expression and vancomycin (VAN) treatment outcomes in experimental IE due to MRSA. RESULTS The PurR-mediated repression of purine biosynthesis was confirmed by enhanced purF expression and production of an intermediate purine metabolite in purR mutant strain. In addition, enhanced expression of the transcriptional regulators, sigB and sarA, and their key downstream virulence genes (eg, fnbA, and hla) was demonstrated in the purR mutant in vitro and within infected cardiac vegetations. Furthermore, purR deficiency enhanced fnbA/fnbB transcription, translating to increased fibronectin adhesion versus the wild type and purR-complemented strains. Notably, the purR mutant was refractory to significant reduction in target tissues MRSA burden following VAN treatment in the IE model. CONCLUSIONS These findings suggest that the purine biosynthetic pathway intersects the coordination of virulence factor expression and in vivo persistence during VAN treatment, and may represent an avenue for novel antimicrobial development targeting MRSA.
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Affiliation(s)
- Yan Q Xiong
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Yi Li
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Mariya I Goncheva
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Ahmed M Elsayed
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Fengli Zhu
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Liang Li
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Wessam Abdelhady
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Ronald S Flannagan
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Michael R Yeaman
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Medicine, Division of Molecular Medicine, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Arnold S Bayer
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
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Li J, Lu T, Chu Y, Zhang Y, Zhang J, Fu W, Sun J, Liu Y, Liao X, Zhou Y. Cinnamaldehyde targets SarA to enhance β-lactam antibiotic activity against methicillin-resistant Staphylococcus aureus. MLIFE 2024; 3:291-306. [PMID: 38948140 PMCID: PMC11211666 DOI: 10.1002/mlf2.12121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/02/2024] [Accepted: 02/19/2024] [Indexed: 07/02/2024]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a current global public health problem due to its increasing resistance to the most recent antibiotic therapies. One critical approach is to develop ways to revitalize existing antibiotics. Here, we show that the phytogenic compound cinnamaldehyde (CIN) and β-lactam antibiotic combinations can functionally synergize and resensitize clinical MRSA isolates to β-lactam therapy and inhibit MRSA biofilm formation. Mechanistic studies indicated that the CIN potentiation effect on β-lactams was primarily the result of inhibition of the mecA expression by targeting the staphylococcal accessory regulator sarA. CIN alone or in combination with β-lactams decreased sarA gene expression and increased SarA protein phosphorylation that impaired SarA binding to the mecA promoter element and downregulated virulence genes such as those encoding biofilm, α-hemolysin, and adhesin. Perturbation of SarA-mecA binding thus interfered with PBP2a biosynthesis and this decreased MRSA resistance to β-lactams. Furthermore, CIN fully restored the anti-MRSA activities of β-lactam antibiotics in vivo in murine models of bacteremia and biofilm infections. Together, our results indicated that CIN acts as a β-lactam adjuvant and can be applied as an alternative therapy to combat multidrug-resistant MRSA infections.
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Affiliation(s)
- Jianguo Li
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Tingyin Lu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yuefei Chu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yuejun Zhang
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Jing Zhang
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
- Yantai Fushan Center for Animal Disease Control and PreventionYantaiChina
| | - Wenzhen Fu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Jian Sun
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yahong Liu
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Xiao‐Ping Liao
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
| | - Yu‐Feng Zhou
- State Key Laboratory for Animal Disease Control and PreventionSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety EvaluationSouth China Agricultural UniversityGuangzhouChina
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3
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Li JG, Chen XF, Lu TY, Zhang J, Dai SH, Sun J, Liu YH, Liao XP, Zhou YF. Increased Activity of β-Lactam Antibiotics in Combination with Carvacrol against MRSA Bacteremia and Catheter-Associated Biofilm Infections. ACS Infect Dis 2023; 9:2482-2493. [PMID: 38019707 DOI: 10.1021/acsinfecdis.3c00338] [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] [Indexed: 12/01/2023]
Abstract
β-Lactam antibiotics are the mainstay for the treatment of staphylococcal infections, but their utility is greatly limited by the emergence and rapid dissemination of methicillin-resistant Staphylococcus aureus (MRSA). Herein, we evaluated the ability of the plant-derived monoterpene carvacrol to act as an antibiotic adjuvant, revitalizing the anti-MRSA activity of β-lactam antibiotics. Increased susceptibility of MRSA to β-lactam antibiotics and significant synergistic activities were observed with carvacrol-based combinations. Carvacrol significantly inhibited MRSA biofilms and reduced the production of exopolysaccharide, polysaccharide intercellular adhesin, and extracellular DNA and showed synergistic biofilm inhibition in combination with β-lactams. Transcriptome analysis revealed profound downregulation in the expression of genes involved in two-component systems and S. aureus infection. Mechanistic studies indicate that carvacrol inhibits the expression of staphylococcal accessory regulator sarA and interferes with SarA-mecA promoter binding that decreases mecA-mediated β-lactam resistance. Consistently, the in vivo experiment also supported that carvacrol restored MRSA sensitivity to β-lactam antibiotic treatments in both murine models of bacteremia and biofilm-associated infection. Our results indicated that carvacrol has a potential role as a combinatorial partner with β-lactam antibiotics to address MRSA infections.
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Affiliation(s)
- Jian-Guo Li
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Feng Chen
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Ting-Yin Lu
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Jing Zhang
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
- Yantai Fushan Center for Animal Disease Control and Prevention, Fushan, Yantai, Shandong 265500, China
| | - Shu-He Dai
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Jian Sun
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Ya-Hong Liu
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Xiao-Ping Liao
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
| | - Yu-Feng Zhou
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China
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Parsons JB, Westgeest AC, Conlon BP, Fowler VG. Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia: Host, Pathogen, and Treatment. Antibiotics (Basel) 2023; 12:455. [PMID: 36978320 PMCID: PMC10044482 DOI: 10.3390/antibiotics12030455] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/02/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a devastating pathogen responsible for a variety of life-threatening infections. A distinctive characteristic of this pathogen is its ability to persist in the bloodstream for several days despite seemingly appropriate antibiotics. Persistent MRSA bacteremia is common and is associated with poor clinical outcomes. The etiology of persistent MRSA bacteremia is a result of the complex interplay between the host, the pathogen, and the antibiotic used to treat the infection. In this review, we explore the factors related to each component of the host-pathogen interaction and discuss the clinical relevance of each element. Next, we discuss the treatment options and diagnostic approaches for the management of persistent MRSA bacteremia.
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Affiliation(s)
- Joshua B. Parsons
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Annette C. Westgeest
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Department of Infectious Diseases, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Brian P. Conlon
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Vance G. Fowler
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Duke Clinical Research Institute, Durham, NC 27710, USA
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5
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MRSA Isolates from Patients with Persistent Bacteremia Generate Nonstable Small Colony Variants In Vitro within Macrophages and Endothelial Cells during Prolonged Vancomycin Exposure. Infect Immun 2023; 91:e0042322. [PMID: 36602380 PMCID: PMC9872686 DOI: 10.1128/iai.00423-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus (especially methicillin-resistant S. aureus [MRSA]) is frequently associated with persistent bacteremia (PB) during vancomycin therapy despite consistent susceptibility in vitro. Strategic comparisons of PB strains versus those from vancomycin-resolving bacteremia (RB) would yield important mechanistic insights into PB outcomes. Clinical PB versus RB isolates were assessed in vitro for intracellular replication and small colony variant (SCV) formation within macrophages and endothelial cells (ECs) in the presence or absence of exogenous vancomycin. In both macrophages and ECs, PB and RB isolates replicated within lysosome-associated membrane protein-1 (LAMP-1)-positive compartments. PB isolates formed nonstable small colony variants (nsSCVs) in vancomycin-exposed host cells at a significantly higher frequency than matched RB isolates (in granulocyte-macrophage colony-stimulating factor [GM-CSF], human macrophages PB versus RB, P < 0.0001 at 48 h; in ECs, PB versus RB, P < 0.0001 at 24 h). This phenotype could represent one potential basis for the unique ability of PB isolates to adaptively resist vancomycin therapy and cause PB in humans. Elucidating the molecular mechanism(s) by which PB strains form nsSCVs could facilitate the discovery of novel treatment strategies to mitigate PB due to MRSA.
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Rodrigues Lopes I, Alcantara LM, Silva RJ, Josse J, Vega EP, Cabrerizo AM, Bonhomme M, Lopez D, Laurent F, Vandenesch F, Mano M, Eulalio A. Microscopy-based phenotypic profiling of infection by Staphylococcus aureus clinical isolates reveals intracellular lifestyle as a prevalent feature. Nat Commun 2022; 13:7174. [PMID: 36418309 PMCID: PMC9684519 DOI: 10.1038/s41467-022-34790-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/08/2022] [Indexed: 11/24/2022] Open
Abstract
Staphylococcus aureus is increasingly recognized as a facultative intracellular pathogen, although the significance and pervasiveness of its intracellular lifestyle remain controversial. Here, we applied fluorescence microscopy-based infection assays and automated image analysis to profile the interaction of 191 S. aureus isolates from patients with bone/joint infections, bacteremia, and infective endocarditis, with four host cell types, at five times post-infection. This multiparametric analysis revealed that almost all isolates are internalized and that a large fraction replicate and persist within host cells, presenting distinct infection profiles in non-professional vs. professional phagocytes. Phenotypic clustering highlighted interesting sub-groups, including one comprising isolates exhibiting high intracellular replication and inducing delayed host death in vitro and in vivo. These isolates are deficient for the cysteine protease staphopain A. This study establishes S. aureus intracellular lifestyle as a prevalent feature of infection, with potential implications for the effective treatment of staphylococcal infections.
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Affiliation(s)
- Ines Rodrigues Lopes
- grid.8051.c0000 0000 9511 4342RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal ,grid.8051.c0000 0000 9511 4342Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Laura Maria Alcantara
- grid.8051.c0000 0000 9511 4342RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Ricardo Jorge Silva
- grid.8051.c0000 0000 9511 4342Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Jerome Josse
- grid.15140.310000 0001 2175 9188Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Elena Pedrero Vega
- grid.4711.30000 0001 2183 4846National Centre for Biotechnology, Spanish National Research Council (CNB-CSIC), Madrid, Spain
| | - Ana Marina Cabrerizo
- grid.4711.30000 0001 2183 4846National Centre for Biotechnology, Spanish National Research Council (CNB-CSIC), Madrid, Spain
| | - Melanie Bonhomme
- grid.15140.310000 0001 2175 9188Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Daniel Lopez
- grid.4711.30000 0001 2183 4846National Centre for Biotechnology, Spanish National Research Council (CNB-CSIC), Madrid, Spain
| | - Frederic Laurent
- grid.15140.310000 0001 2175 9188Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France ,grid.413852.90000 0001 2163 3825Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Francois Vandenesch
- grid.15140.310000 0001 2175 9188Centre International de Recherche en Infectiologie (CIRI), Université de Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France ,grid.413852.90000 0001 2163 3825Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Miguel Mano
- grid.8051.c0000 0000 9511 4342Functional Genomics and RNA-based Therapeutics Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal ,grid.8051.c0000 0000 9511 4342Department of Life Sciences, University of Coimbra, Coimbra, Portugal ,grid.13097.3c0000 0001 2322 6764British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London, London, United Kingdom
| | - Ana Eulalio
- grid.8051.c0000 0000 9511 4342RNA & Infection Laboratory, Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal ,grid.7311.40000000123236065Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal ,grid.7445.20000 0001 2113 8111Department of Life Sciences, Imperial College London, London, United Kingdom
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Microbiological and Molecular Features Associated with Persistent and Relapsing Staphylococcus aureus Prosthetic Joint Infection. Antibiotics (Basel) 2022; 11:antibiotics11081119. [PMID: 36009988 PMCID: PMC9405193 DOI: 10.3390/antibiotics11081119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/07/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Background: Persistent and relapsing prosthetic joint infection (PJI) due to Staphylococcus aureus presents a clinical challenge. This study aimed to provide an extensive description of phenotypic and genomic changes that could be related to persistence or relapse. Methods: Initial and second S. aureus isolates from 6 cases of persistent and relapsing PJI, along with clinical isolates from 8 cases, with favorable outcome were included. All isolates were studied by phenotypic and genotypic approaches. Results: Recurrent S. aureus isolates exhibited a significant increase in adhesive capacity, invasion and persistence compared to resolved isolates. No association was found for the presence or absence of certain genes with the persistence or relapse of PJI. All sequential isolates showed identical sequence type (ST). Resistance gene loss during the infection and a great diversity of variants in different virulence genes between the pair of strains, mainly in genes encoding adhesins such as fnbA, were observed. Conclusions: S. aureus-caused relapse and persistence PJI is associated with bacterial phenotypical and genotypical adaptation. The main paths of adaptation were persistence in the intracellular compartment, and the loss of antibiotic resistance genes and variant acquisition, especially in genes encoding adhesins.
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Horká M, Růžička F, Siváková A, Karásek P, Šalplachta J, Pantůček R, Roth M. Capillary electrophoretic methods for classification of methicillin-resistant Staphylococcus aureus (MRSA) clones. Anal Chim Acta 2022; 1227:340305. [DOI: 10.1016/j.aca.2022.340305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/19/2022] [Accepted: 08/20/2022] [Indexed: 11/26/2022]
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Xiao X, Li Y, Li L, Xiong YQ. Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) Genetic Factors Involved in Human Endothelial Cells Damage, an Important Phenotype Correlated with Persistent Endovascular Infection. Antibiotics (Basel) 2022; 11:antibiotics11030316. [PMID: 35326779 PMCID: PMC8944730 DOI: 10.3390/antibiotics11030316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/18/2022] [Accepted: 02/24/2022] [Indexed: 01/18/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of life-threatening endovascular infections. Endothelial cell (EC) damage is a key factor in the pathogenesis of these syndromes. However, genetic factors related to the EC damage have not been well studied. This study aims to identify genetic determinants that impact human EC damage by screening the genome-wide Nebraska Transposon Mutant Library (NTML). A well-established MTT assay was used to test the in vitro damage of human EC cell line (HMEC-1) caused by each mutant strain in the NTML. We first confirmed some global regulators and genes positively impact the EC damage, which is consistent with published results. These data support the utility of the high-throughput approach. Importantly, we demonstrated 317 mutants significantly decreased the EC damage, while only 6 mutants enhanced the EC damage vs. parental JE2 strain. The majority of these genes have not been previously defined to affect human EC damage. Interestingly, many of these newly identified genes are involved in metabolism, genetic and environmental information processing, and cellular processes. These results advance our knowledge of staphylococcal genetic factors related to human EC damage which may provide novel targets for the development of effective agents against MRSA endovascular infection.
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Affiliation(s)
- Xia Xiao
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (X.X.); (Y.L.); (L.L.)
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Yi Li
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (X.X.); (Y.L.); (L.L.)
| | - Liang Li
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (X.X.); (Y.L.); (L.L.)
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Yan Q. Xiong
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (X.X.); (Y.L.); (L.L.)
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Correspondence: ; Tel.: +1-310-222-3545
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10
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New Mechanistic Insights into Purine Biosynthesis with Second Messenger c-di-AMP in Relation to Biofilm-Related Persistent Methicillin-Resistant Staphylococcus aureus Infections. mBio 2021; 12:e0208121. [PMID: 34724823 PMCID: PMC8561390 DOI: 10.1128/mbio.02081-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) endovascular infections represent a significant clinically challenging subset of invasive, life-threatening S. aureus infections. We have recently demonstrated that purine biosynthesis plays an important role in such persistent infections. Cyclic di-AMP (c-di-AMP) is an essential and ubiquitous second messenger that regulates many cellular pathways in bacteria. However, whether there is a regulatory connection between the purine biosynthesis pathway and c-di-AMP impacting persistent outcomes was not known. Here, we demonstrated that the purine biosynthesis mutant MRSA strain, the ΔpurF strain (compared to its isogenic parental strain), exhibited the following significant differences in vitro: (i) lower ADP, ATP, and c-di-AMP levels; (ii) less biofilm formation with decreased extracellular DNA (eDNA) levels and Triton X-100-induced autolysis paralleling enhanced expressions of the biofilm formation-related two-component regulatory system lytSR and its downstream gene lrgB; (iii) increased vancomycin (VAN)-binding and VAN-induced lysis; and (iv) decreased wall teichoic acid (WTA) levels and expression of the WTA biosynthesis-related gene, tarH. Substantiating these data, the dacA (encoding diadenylate cyclase enzyme required for c-di-AMP synthesis) mutant strain (dacAG206S strain versus its isogenic wild-type MRSA and dacA-complemented strains) showed significantly decreased c-di-AMP levels, similar in vitro effects as seen above for the purF mutant and hypersusceptible to VAN treatment in an experimental biofilm-related MRSA endovascular infection model. These results reveal an important intersection between purine biosynthesis and c-di-AMP that contributes to biofilm-associated persistence in MRSA endovascular infections. This signaling pathway represents a logical therapeutic target against persistent MRSA infections.
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Cardoso Guimarães L, Marques de Souza B, de Oliveira Whitaker C, Abreu F, Barreto Rocha Ferreira R, Dos Santos KRN. Increased biofilm formation by Staphylococcus aureus clinical isolates on surfaces covered with plasma proteins. J Med Microbiol 2021; 70. [PMID: 34338626 DOI: 10.1099/jmm.0.001389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Introduction. Biofilm formation is a major virulence factor associated with Staphylococcus aureus infections. However, the influence of plasma proteins on biofilm formation of clinical isolates in vitro remains unclear.Hypotheses. We hypothesized that coating surfaces with plasma proteins might induce biofilm formation by S. aureus of different clonal lineages.Aim. To evaluate biofilm production by clinical S. aureus isolates of different clonal lineages isolated in Rio de Janeiro hospitals and investigated the presence of biofilm-associated genes.Methodology. This study assessed biofilm production of 60 S. aureus isolates in polystyrene microtitre plates with and without fibrinogen or fibronectin. The biochemical composition of the biofilm matrices was determined and the biofilm formation on fibrinogen-coated surfaces was also evaluated by confocal laser scanning microscopy. The presence of biofilm-related genes was detected by PCR, and the typing and functionality of agr operon was also evaluated.Results. Most of the isolates (45 %) were weak biofilm producers or non-producers. However, most of them presented a significant increase in biofilm production on plates covered with plasma proteins. There was no significant difference in biofilm formation between methicillin-resistant and -susceptible S. aureus isolates, or between different clonal lineages, except for ST30-IV (weak producers) and ST239-III (strong producers). The fnbB gene was associated with higher biofilm production.Conclusion. An increase in biofilm production in the presence of plasma proteins highlights the importance of investigating biofilm formation by S. aureus clinical isolates under different conditions since this virulence factor contributes to persistent infections and increased resistance to antimicrobials.
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Affiliation(s)
- Lorrayne Cardoso Guimarães
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bruna Marques de Souza
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | - Fernanda Abreu
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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12
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Wächter H, Yörük E, Becker K, Görlich D, Kahl BC. Correlations of Host and Bacterial Characteristics with Clinical Parameters and Survival in Staphylococcus aureus Bacteremia. J Clin Med 2021; 10:1371. [PMID: 33800644 PMCID: PMC8037130 DOI: 10.3390/jcm10071371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/19/2021] [Accepted: 03/24/2021] [Indexed: 01/14/2023] Open
Abstract
Staphylococcus aureus bacteremia (SAB) is a frequent, severe condition that occurs in patients of all age groups and affects clinical departments of all medical fields. It is associated with a high mortality rate of 20-30%. In this study, we analyzed patient mortality associated with SAB at our tertiary care university hospital, assessed the clinical management in terms of administered antimicrobial therapy, and determined which factors have an impact on the clinical course and outcome of patients with this disease. We collected clinical data and blood culture isolates of 178 patients diagnosed with SAB between May 2013 and July 2015. For this study, bacteria were cultured and analyzed concerning their phenotype, hemolysis activity, biofilm formation, nuclease activity, prevalence of toxin genes, spa and agr type. Overall mortality was 24.2% and 30-day mortality was 14.6%. Inadequate initial therapy was administered to 26.2% of patients and was associated with decreased survival (p = 0.041). Other factors associated with poor survival were patient age (p = 0.003), agr type 4 (p ≤ 0.001) and pathological leukocyte counts (p = 0.029 if elevated and p = 0.003 if lowered). The type of infection focus, spa clonal complex and enterotoxin genes seg and sei had an impact on severity of inflammation. Our results indicate that mortality and burden of disease posed by SAB are high at our university hospital.
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Affiliation(s)
- Hannah Wächter
- Institute of Medical Microbiology, University Hospital Münster, 48149 Münster, Germany; (H.W.); (E.Y.); (K.B.)
| | - Erdal Yörük
- Institute of Medical Microbiology, University Hospital Münster, 48149 Münster, Germany; (H.W.); (E.Y.); (K.B.)
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, 48149 Münster, Germany; (H.W.); (E.Y.); (K.B.)
- Friedrich Loeffler-Institute of Medical Microbiology, University Medicine Greifswald, 17475 Greifswald, Germany
| | - Dennis Görlich
- Institute of Biostatistics and Clinical Research, University Hospital Münster, 48149 Münster, Germany;
| | - Barbara C. Kahl
- Institute of Medical Microbiology, University Hospital Münster, 48149 Münster, Germany; (H.W.); (E.Y.); (K.B.)
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13
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Li L, Bayer AS, Cheung A, Lu L, Abdelhady W, Donegan NP, Hong JI, Yeaman MR, Xiong YQ. The Stringent Response Contributes to Persistent Methicillin-Resistant Staphylococcus aureus Endovascular Infection Through the Purine Biosynthetic Pathway. J Infect Dis 2021; 222:1188-1198. [PMID: 32333768 DOI: 10.1093/infdis/jiaa202] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/21/2020] [Indexed: 02/02/2023] Open
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) endovascular infections represent a significant clinical-therapeutic challenge. Of particular concern is antibiotic treatment failure in infections caused by MRSA that are "susceptible" to antibiotic in vitro. In the current study, we investigate specific purine biosynthetic pathways and stringent response mechanism(s) related to this life-threatening syndrome using genetic matched persistent and resolving MRSA clinical bacteremia isolates (PB and RB, respectively), and isogenic MRSA strain sets. We demonstrate that PB isolates (vs RB isolates) have significantly higher (p)ppGpp production, phenol-soluble-modulin expression, polymorphonuclear leukocyte lysis and survival, fibronectin/endothelial cell (EC) adherence, and EC damage. Importantly, an isogenic strain set, including JE2 parental, relP-mutant and relP-complemented strains, translated the above findings into significant outcome differences in an experimental endocarditis model. These observations indicate a significant regulation of purine biosynthesis on stringent response, and suggest the existence of a previously unknown adaptive genetic mechanism in persistent MRSA infection.
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Affiliation(s)
- Liang Li
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Arnold S Bayer
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA.,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA.,David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Ambrose Cheung
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Lou Lu
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA.,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA.,Division of Molecular Medicine, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA
| | - Wessam Abdelhady
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Niles P Donegan
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Jong-In Hong
- Department of Chemistry, Seoul National University, Seoul, Korea
| | - Michael R Yeaman
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA.,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA.,David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Division of Molecular Medicine, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA
| | - Yan Q Xiong
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA.,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA.,David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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14
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19/asset/e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, 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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15
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Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020; 84:84/3/e00026-19. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19] [Citation(s) in RCA: 284] [Impact Index Per Article: 71.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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16
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Impact of the Novel Prophage ϕSA169 on Persistent Methicillin-Resistant Staphylococcus aureus Endovascular Infection. mSystems 2020; 5:5/3/e00178-20. [PMID: 32606024 PMCID: PMC7329321 DOI: 10.1128/msystems.00178-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) endovascular infections are life-threatening syndromes with few therapeutic options. The potential impact of bacteriophages on the persistent outcome has not been well studied. In this study, we investigated the role of a novel prophage (ϕSA169) in MRSA persistence by using a lysogen-free clinically resolving bacteremia (RB) isolate and comparing it to a derivative which was obtained by infecting the RB strain with ϕSA169, which has been lysogenized in a clinical persistent MRSA bacteremia (PB) isolate. Similar to the PB isolate, the ϕSA169-lysogenized RB strain exhibited well-defined in vitro and in vivo phenotypic and genotypic signatures related to the persistent outcome, including earlier activation of global regulators (i.e., sigB, sarA, agr RNAIII, and sae); higher expression of a critical purine biosynthesis gene, purF; and higher growth rates accompanied by lower ATP levels and vancomycin (VAN) susceptibility and stronger δ-hemolysin and biofilm formation versus its isogenic parental RB isolate. Notably, the contribution of ϕSA169 in persistent outcome with VAN treatment was confirmed in an experimental infective endocarditis model. Taken together, these results indicate the critical role of the prophage ϕSA169 in persistent MRSA endovascular infections. Further studies are needed to identify the mechanisms of ϕSA169 in mediating the persistence, as well as establishing the scope of impact, of this prophage in other PB strains.IMPORTANCE Bacteriophages are viruses that invade the bacterial host, disrupt bacterial metabolism, and cause the bacterium to lyse. Because of its remarkable antibacterial activity and unique advantages over antibiotics, for instance, bacteriophage is specific for one species of bacteria and resistance to phage is less common than resistance to antibiotics. Indeed, bacteriophage therapy for treating infections due to multidrug-resistant pathogens in humans has become a research hot spot. However, it is also worth considering that bacteriophages are transferable and could cotransfer host chromosomal genes, e.g., virulence and antimicrobial resistance genes, while lysogenizing and integrating into the bacterial chromosome (prophage), thus playing a role in bacterial evolution and virulence. In the current study, we identified a novel prophage, ϕSA169, from a clinical persistent MRSA bacteremia isolate, and we determined that ϕSA169 mediated well-defined in vitro and in vivo phenotypic and genotypic signatures related to the persistent outcome, which may represent a unique and important persistent mechanism(s).
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17
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Li L, Wang G, Cheung A, Abdelhady W, Seidl K, Xiong YQ. MgrA Governs Adherence, Host Cell Interaction, and Virulence in a Murine Model of Bacteremia Due to Staphylococcus aureus. J Infect Dis 2020; 220:1019-1028. [PMID: 31177268 DOI: 10.1093/infdis/jiz219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/26/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND MgrA is an important global virulence gene regulator in Staphylococcus aureus. In the present study, the role of mgrA in host-pathogen interactions related to virulence was explored in both methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. METHODS In vitro susceptibilities to human defense peptides (HDPs), adherence to fibronectin (Fn) and endothelial cells (ECs), EC damage, α-toxin production, expression of global regulator (eg, agr RNAIII) and its downstream effectors (eg, α-toxin [hla] and Fn binding protein A [fnbA]), MgrA binding to fnbA promoter, and the effect on HDP-induced mprF and dltA expression were analyzed. The impact of mgrA on virulence was evaluated using a mouse bacteremia model. RESULTS mgrA mutants displayed significantly higher susceptibility to HDPs, which might be related to the decreased HDP-induced mprF and dltA expression but decreased Fn and EC adherence, EC damage, α-toxin production, agr RNAIII, hla and fnbA expression, and attenuated virulence in the bacteremia model as compared to their respective parental and mgrA-complemented strains. Importantly, direct binding of MgrA to the fnbA promoter was observed. CONCLUSIONS These results suggest that mgrA mediates host-pathogen interactions and virulence and may provide a novel therapeutic target for invasive S. aureus infections.
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Affiliation(s)
- Liang Li
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance
| | - Genzhu Wang
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance
| | | | - Wessam Abdelhady
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance
| | - Kati Seidl
- University Hospital of Zurich, Switzerland
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance.,David Geffen School of Medicine at UCLA, Los Angeles, California
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18
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Zhou YF, Li L, Tao MT, Sun J, Liao XP, Liu YH, Xiong YQ. Linezolid and Rifampicin Combination to Combat cfr-Positive Multidrug-Resistant MRSA in Murine Models of Bacteremia and Skin and Skin Structure Infection. Front Microbiol 2020; 10:3080. [PMID: 31993042 PMCID: PMC6971047 DOI: 10.3389/fmicb.2019.03080] [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: 09/09/2019] [Accepted: 12/19/2019] [Indexed: 01/16/2023] Open
Abstract
Linezolid resistance mediated by the cfr gene in MRSA represents a global concern. We investigated relevant phenotype differences between cfr-positive and -negative MRSA that contribute to pathogenesis, and the efficacy of linezolid-based combination therapies in murine models of bacteremia and skin and skin structure infection (SSSI). As a group, cfr-positive MRSA exhibited significantly reduced susceptibilities to the host defense peptides tPMPs, human neutrophil peptide-1 (hNP-1), and cathelicidin LL-37 (P < 0.01). In addition, increased binding to fibronectin (FN) and endothelial cells paralleled robust biofilm formation in cfr-positive vs. -negative MRSA. In vitro phenotypes of cfr-positive MRSA translated into poor outcomes of linezolid monotherapy in vivo in murine bacteremia and SSSI models. Importantly, rifampicin showed synergistic activity as a combinatorial partner with linezolid, and the EC50 of linezolid decreased 6-fold in the presence of rifampicin. Furthermore, this combination therapy displayed efficacy against cfr-positive MRSA at clinically relevant doses. Altogether, these data suggest that the use of linezolid in combination with rifampicin poses a viable therapeutic alternative for bacteremia and SSSI caused by cfr-positive multidrug resistant MRSA.
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Affiliation(s)
- Yu-Feng Zhou
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Liang Li
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States
| | - Meng-Ting Tao
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Jian Sun
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Xiao-Ping Liao
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Ya-Hong Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Yan Q Xiong
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States.,David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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19
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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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20
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Genetic variation of DNA methyltransferase-3A contributes to protection against persistent MRSA bacteremia in patients. Proc Natl Acad Sci U S A 2019; 116:20087-20096. [PMID: 31527248 PMCID: PMC6778225 DOI: 10.1073/pnas.1909849116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The severity and duration of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia varies widely between individuals. Host factors predisposing to persistent MRSA bacteremia are poorly understood, although genetic association studies are beginning to identify potentially influential variants. We found an association between the A/C heterozygous genotype in the DNMT3A correlating with shorter time to resolution of MRSA bacteremia. Using in vitro macrophage assays and murine sepsis models, we demonstrated that DNMT3A variants may alter host response to infection through increased methylation of key regulatory genes, resulting in reduced interleukin-10 production and in turn, allowing for a more protective immune response that clears infection. An improved understanding of the factors predisposing to persistent MRSA bacteremia may help to discover better treatment options. The role of the host in development of persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is not well understood. A cohort of prospectively enrolled patients with persistent methicillin-resistant S. aureus bacteremia (PB) and resolving methicillin-resistant S. aureus bacteremia (RB) matched by sex, age, race, hemodialysis status, diabetes mellitus, and presence of implantable medical device was studied to gain insights into this question. One heterozygous g.25498283A > C polymorphism located in the DNMT3A intronic region of chromosome 2p with no impact in messenger RNA (mRNA) expression was more common in RB (21 of 34, 61.8%) than PB (3 of 34, 8.8%) patients (P = 7.8 × 10−6). Patients with MRSA bacteremia and g.25498283A > C genotype exhibited significantly higher levels of methylation in gene-regulatory CpG island regions (Δmethylation = 4.1%, P < 0.0001) and significantly lower serum levels of interleukin-10 (IL-10) than patients with MRSA bacteremia without DNMT3A mutation (A/C: 9.7038 pg/mL vs. A/A: 52.9898 pg/mL; P = 0.0042). Expression of DNMT3A was significantly suppressed in patients with S. aureus bacteremia and in S. aureus-challenged primary human macrophages. Small interfering RNA (siRNA) silencing of DNMT3A expression in human macrophages caused increased IL-10 response upon S. aureus stimulation. Treating macrophages with methylation inhibitor 5-Aza-2′-deoxycytidine resulted in increased levels of IL-10 when challenged with S. aureus. In the murine sepsis model, methylation inhibition increased susceptibility to S. aureus. These findings indicate that g.25498283A > C genotype within DNMT3A contributes to increased capacity to resolve MRSA bacteremia, potentially through a mechanism involving increased methylation of gene-regulatory regions and reduced levels of antiinflammatory cytokine IL-10.
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21
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Bicarbonate Resensitization of Methicillin-Resistant Staphylococcus aureus to β-Lactam Antibiotics. Antimicrob Agents Chemother 2019; 63:AAC.00496-19. [PMID: 31010857 PMCID: PMC6591647 DOI: 10.1128/aac.00496-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/07/2019] [Indexed: 12/24/2022] Open
Abstract
Endovascular infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major health care concern, especially infective endocarditis (IE). Standard antimicrobial susceptibility testing (AST) defines most MRSA strains as “resistant” to β-lactams, often leading to the use of costly and/or toxic treatment regimens. In this investigation, five prototype MRSA strains, representing the range of genotypes in current clinical circulation, were studied. Endovascular infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major health care concern, especially infective endocarditis (IE). Standard antimicrobial susceptibility testing (AST) defines most MRSA strains as “resistant” to β-lactams, often leading to the use of costly and/or toxic treatment regimens. In this investigation, five prototype MRSA strains, representing the range of genotypes in current clinical circulation, were studied. We identified two distinct MRSA phenotypes upon AST using standard media, with or without sodium bicarbonate (NaHCO3) supplementation: one highly susceptible to the antistaphylococcal β-lactams oxacillin and cefazolin (NaHCO3 responsive) and one resistant to such agents (NaHCO3 nonresponsive). These phenotypes accurately predicted clearance profiles of MRSA from target tissues in experimental MRSA IE treated with each β-lactam. Mechanistically, NaHCO3 reduced the expression of two key genes involved in the MRSA phenotype, mecA and sarA, leading to decreased production of penicillin-binding protein 2a (that mediates methicillin resistance), in NaHCO3-responsive (but not in NaHCO3-nonresponsive) strains. Moreover, both cefazolin and oxacillin synergistically killed NaHCO3-responsive strains in the presence of the host defense antimicrobial peptide (LL-37) in NaHCO3-supplemented media. These findings suggest that AST of MRSA strains in NaHCO3-containing media may potentially identify infections caused by NaHCO3-responsive strains that are appropriate for β-lactam therapy.
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22
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Kwiecinski JM, Jacobsson G, Horswill AR, Josefsson E, Jin T. Biofilm formation by Staphylococcus aureus clinical isolates correlates with the infection type. Infect Dis (Lond) 2019. [PMID: 30985241 DOI: 10.1080/2374423520191593499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND Biofilms are involved in many Staphylococcus aureus infections, but relation of biofilm formation and the infection types or the clinical outcomes remain unclear. METHODS We measured biofilm formation, with a microtiter plate assay, of a collection of methicillin-sensitive clinical isolates from 159 invasive S. aureus infections, encompassing all cases occurring within a hospital catchment area during two years, and from additional 49 non-invasive skin infections from the same region. Results were related to available clinical and microbiological documentation. RESULTS Isolates from medical device infections (intravenous line-associated and prosthetic joint infections), as well as isolates from superficial skin infections, were particularly proficient in forming biofilms. No increased biofilm-forming capacity was seen in isolates from endocarditis, osteomyelitis, or other infections. There was also a correlation of biofilm formation with the agr type of the isolates. Thicker biofilms were more resistant to antibiotic treatment in vitro. No correlation between biofilm formation and clinical outcomes was noted. CONCLUSIONS S. aureus isolates from 'classical' biofilm-related infections, but also from superficial skin infections, are especially proficient in forming biofilms. There is, however, no obvious relation of biofilm-forming capacity of isolates and the clinical outcome of the infection, and more studies on this issue are needed.
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Affiliation(s)
- Jakub M Kwiecinski
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden.,b Department of Immunology and Microbiology , University of Colorado School of Medicine , Aurora , CO , USA
| | - Gunnar Jacobsson
- c Department of Infectious Diseases , Skaraborg Hospital , Skövde , Sweden
| | - Alexander R Horswill
- b Department of Immunology and Microbiology , University of Colorado School of Medicine , Aurora , CO , USA.,d Department of Veterans Affairs Eastern Colorado Healthcare System , Denver , CO , USA
| | - Elisabet Josefsson
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
| | - Tao Jin
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden.,e Department of Rheumatology , Sahlgrenska University Hospital , Gothenburg , Sweden
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23
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Phenotypic and Genotypic Characteristics of Methicillin-Resistant Staphylococcus aureus (MRSA) Related to Persistent Endovascular Infection. Antibiotics (Basel) 2019; 8:antibiotics8020071. [PMID: 31146412 PMCID: PMC6627527 DOI: 10.3390/antibiotics8020071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 12/03/2022] Open
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (PB) represents an important subset of S. aureus infection and correlates with poor clinical outcomes. MRSA isolates from patients with PB differ significantly from those of resolving bacteremia (RB) with regard to several in vitro phenotypic and genotypic profiles. For instance, PB strains exhibit less susceptibility to cationic host defense peptides and vancomycin (VAN) killing under in vivo-like conditions, greater damage to endothelial cells, thicker biofilm formation, altered growth rates, early activation of many global virulence regulons (e.g., sigB, sarA, sae and agr) and higher expression of purine biosynthesis genes (e.g., purF) than RB strains. Importantly, PB strains are significantly more resistant to VAN treatment in experimental infective endocarditis as compared to RB strains, despite similar VAN minimum inhibitory concentrations (MICs) in vitro. Here, we review relevant phenotypic and genotypic characteristics related to the PB outcome. These and future insights may improve our understanding of the specific mechanism(s) contributing to the PB outcome, and aid in the development of novel therapeutic and preventative measures against this life-threatening infection.
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24
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Kwiecinski JM, Jacobsson G, Horswill AR, Josefsson E, Jin T. Biofilm formation by Staphylococcus aureus clinical isolates correlates with the infection type. Infect Dis (Lond) 2019; 51:446-451. [PMID: 30985241 DOI: 10.1080/23744235.2019.1593499] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Biofilms are involved in many Staphylococcus aureus infections, but relation of biofilm formation and the infection types or the clinical outcomes remain unclear. METHODS We measured biofilm formation, with a microtiter plate assay, of a collection of methicillin-sensitive clinical isolates from 159 invasive S. aureus infections, encompassing all cases occurring within a hospital catchment area during two years, and from additional 49 non-invasive skin infections from the same region. Results were related to available clinical and microbiological documentation. RESULTS Isolates from medical device infections (intravenous line-associated and prosthetic joint infections), as well as isolates from superficial skin infections, were particularly proficient in forming biofilms. No increased biofilm-forming capacity was seen in isolates from endocarditis, osteomyelitis, or other infections. There was also a correlation of biofilm formation with the agr type of the isolates. Thicker biofilms were more resistant to antibiotic treatment in vitro. No correlation between biofilm formation and clinical outcomes was noted. CONCLUSIONS S. aureus isolates from 'classical' biofilm-related infections, but also from superficial skin infections, are especially proficient in forming biofilms. There is, however, no obvious relation of biofilm-forming capacity of isolates and the clinical outcome of the infection, and more studies on this issue are needed.
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Affiliation(s)
- Jakub M Kwiecinski
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden.,b Department of Immunology and Microbiology , University of Colorado School of Medicine , Aurora , CO , USA
| | - Gunnar Jacobsson
- c Department of Infectious Diseases , Skaraborg Hospital , Skövde , Sweden
| | - Alexander R Horswill
- b Department of Immunology and Microbiology , University of Colorado School of Medicine , Aurora , CO , USA.,d Department of Veterans Affairs Eastern Colorado Healthcare System , Denver , CO , USA
| | - Elisabet Josefsson
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
| | - Tao Jin
- a Department of Rheumatology and Inflammation Research , Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden.,e Department of Rheumatology , Sahlgrenska University Hospital , Gothenburg , Sweden
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25
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Methicillin-Resistant Staphylococcus aureus Prosthetic Valve Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management. Clin Microbiol Rev 2019; 32:32/2/e00041-18. [PMID: 30760474 DOI: 10.1128/cmr.00041-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus prosthetic valve endocarditis (PVE) remains among the most morbid bacterial infections, with mortality estimates ranging from 40% to 80%. The proportion of PVE cases due to methicillin-resistant Staphylococcus aureus (MRSA) has grown in recent decades, to account for more than 15% of cases of S. aureus PVE and 6% of all cases of PVE. Because no large studies or clinical trials for PVE have been published, most guidelines on the diagnosis and management of MRSA PVE rely upon expert opinion and data from animal models or related conditions (e.g., coagulase-negative Staphylococcus infection). We performed a review of the literature on MRSA PVE to summarize data on pathogenic mechanisms and updates in epidemiology and therapeutic management and to inform diagnostic strategies and priority areas where additional clinical and laboratory data will be particularly useful to guide therapy. Major updates discussed in this review include novel diagnostics, indications for surgical management, the utility of aminoglycosides in medical therapy, and a review of newer antistaphylococcal agents used for the management of MRSA PVE.
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26
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Pfeil MP, Pyne ALB, Losasso V, Ravi J, Lamarre B, Faruqui N, Alkassem H, Hammond K, Judge PJ, Winn M, Martyna GJ, Crain J, Watts A, Hoogenboom BW, Ryadnov MG. Tuneable poration: host defense peptides as sequence probes for antimicrobial mechanisms. Sci Rep 2018; 8:14926. [PMID: 30297841 PMCID: PMC6175903 DOI: 10.1038/s41598-018-33289-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 09/26/2018] [Indexed: 02/02/2023] Open
Abstract
The spread of antimicrobial resistance stimulates discovery strategies that place emphasis on mechanisms circumventing the drawbacks of traditional antibiotics and on agents that hit multiple targets. Host defense peptides (HDPs) are promising candidates in this regard. Here we demonstrate that a given HDP sequence intrinsically encodes for tuneable mechanisms of membrane disruption. Using an archetypal HDP (cecropin B) we show that subtle structural alterations convert antimicrobial mechanisms from native carpet-like scenarios to poration and non-porating membrane exfoliation. Such distinct mechanisms, studied using low- and high-resolution spectroscopy, nanoscale imaging and molecular dynamics simulations, all maintain strong antimicrobial effects, albeit with diminished activity against pathogens resistant to HDPs. The strategy offers an effective search paradigm for the sequence probing of discrete antimicrobial mechanisms within a single HDP.
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Affiliation(s)
- Marc-Philipp Pfeil
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Alice L B Pyne
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Valeria Losasso
- STFC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD, UK
| | - Jascindra Ravi
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Baptiste Lamarre
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Nilofar Faruqui
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Hasan Alkassem
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- Department of Biochemical Engineering, University College London, London, WC1E 6BT, UK
| | - Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Peter J Judge
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Martyn Winn
- STFC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD, UK
| | | | - Jason Crain
- IBM Research, Yorktown Heights, NY, 10598, USA
| | - Anthony Watts
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
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27
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Li L, Abdelhady W, Donegan NP, Seidl K, Cheung A, Zhou YF, Yeaman MR, Bayer AS, Xiong YQ. Role of Purine Biosynthesis in Persistent Methicillin-Resistant Staphylococcus aureus Infection. J Infect Dis 2018; 218:1367-1377. [PMID: 29868791 PMCID: PMC6151072 DOI: 10.1093/infdis/jiy340] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/01/2018] [Indexed: 11/13/2022] Open
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (PB) represents an important subset of S. aureus endovascular infections. In this study, we investigated potential genetic mechanisms underlying the persistent outcomes. Compared with resolving bacteremia (RB) isolates (defined as isolates associated with negative results of blood cultures 2-4 days after initiation of therapy), PB strains (defined as isolates associated with positive results of blood cultures ≥7 days after initiation of therapy) had significantly earlier onset activation of key virulence regulons and structural genes (eg, sigB, sarA, sae, and cap5), higher expression of purine biosynthesis genes (eg, purF), and faster growth rates, with earlier entrance into stationary phase. Importantly, an isogenic strain set featuring a wild-type MRSA isolate, a purF mutant strain, and a purF-complemented strain and use of strategic purine biosynthesis inhibitors implicated a causal relationship between purine biosynthesis and the in vivo persistent outcomes. These observations suggest that purine biosynthesis plays a key role in the outcome of PB and may represent a new target for enhanced efficacy in treating life-threatening MRSA infections.
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Affiliation(s)
- Liang Li
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
| | - Wessam Abdelhady
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
| | | | - Kati Seidl
- University Hospital of Zurich, Switzerland
| | | | - Yu-Feng Zhou
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
- South China Agricultural University, Guangzhou
| | - Michael R Yeaman
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Arnold S Bayer
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
- David Geffen School of Medicine at UCLA, Los Angeles, California
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28
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Control of Propionibacterium acnes by natural antimicrobial substances: Role of the bacteriocin AS-48 and lysozyme. Sci Rep 2018; 8:11766. [PMID: 30082920 PMCID: PMC6079106 DOI: 10.1038/s41598-018-29580-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 07/16/2018] [Indexed: 12/19/2022] Open
Abstract
We report the high susceptibility of several clinical isolates of Propionibacterium acnes from different sources (skin, bone, wound exudates, abscess or blood contamination) to the head-to-tail cyclized bacteriocin AS-48. This peptide is a feasible candidate for further pharmacological development against this bacterium, due to its physicochemical and biological characteristics, even when it is growing in a biofilm. Thus, the treatment of pre-formed biofilms with AS-48 resulted in a dose- and time-dependent disruption of the biofilm architecture beside the decrease of bacterial viability. Furthermore, we demonstrated the potential of lysozyme to bolster the inhibitory activity of AS-48 against P. acnes, rendering high reductions in the MIC values, even in matrix-growing cultures, according to the results obtained using a range of microscopy and bioassay techniques. The improvement of the activity of AS-48 through its co-formulation with lysozyme may be considered an alternative in the control of P. acnes, especially after proving the absence of cytotoxicity demonstrated by these natural compounds on relevant human skin cell lines. In summary, this study supports that compositions comprising the bacteriocin AS-48 plus lysozyme must be considered as promising candidates for topical applications with medical and pharmaceutical purposes against dermatological diseases such as acne vulgaris.
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29
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Miller WR, Seas C, Carvajal LP, Diaz L, Echeverri AM, Ferro C, Rios R, Porras P, Luna C, Gotuzzo E, Munita JM, Nannini E, Carcamo C, Reyes J, Arias CA. The Cefazolin Inoculum Effect Is Associated With Increased Mortality in Methicillin-Susceptible Staphylococcus aureus Bacteremia. Open Forum Infect Dis 2018; 5:ofy123. [PMID: 29977970 PMCID: PMC6007512 DOI: 10.1093/ofid/ofy123] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/23/2018] [Indexed: 12/15/2022] Open
Abstract
Background Recent studies have favored the use of cefazolin over nafcillin for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. The clinical influence of the cefazolin inoculum effect (CzIE) in the effectiveness of cephalosporins for severe MSSA infections has not been evaluated. Methods We prospectively included patients from 3 Argentinian hospitals with S. aureus bacteremia. Cefazolin minimum inhibitory concentrations (MICs) were determined at standard (105 colony-forming units [CFU]/mL) and high (107 CFU/mL) inoculum. The CzIE was defined as an increase of MIC to ≥16 µg/mL when tested at high inoculum. Whole-genome sequencing was performed in all isolates. Results A total of 77 patients, contributing 89 MSSA isolates, were included in the study; 42 patients (54.5%) had isolates with the CzIE. In univariate analysis, patients with MSSA exhibiting the CzIE had increased 30-day mortality (P = .034) and were more likely to have catheter-associated or unknown source of bacteremia (P = .033) compared with patients infected with MSSA isolates without the CzIE. No statistically significant difference between the groups was observed in age, clinical illness severity, place of acquisition (community vs hospital), or presence of endocarditis. The CzIE remained associated with increased 30-day mortality in multivariate analysis (risk ratio, 2.65; 95% confidence interval, 1.10–6.42; P = .03). MSSA genomes displayed a high degree of heterogeneity, and the CzIE was not associated with a specific lineage. Conclusions In patients with MSSA bacteremia where cephalosporins are used as firstline therapy, the CzIE was associated with increased 30-day mortality. Clinicians should be cautious when using cefazolin as firstline therapy for these infections.
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Affiliation(s)
- William R Miller
- Center for Antimicrobial Resistance and Microbial Genomics, Houston, Texas.,Division of Infectious Diseases, Department of Internal Medicine, Houston, Texas
| | - Carlos Seas
- Hospital Cayetano Heredia and Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Lina P Carvajal
- Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Lorena Diaz
- Center for Antimicrobial Resistance and Microbial Genomics, Houston, Texas.,Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Aura M Echeverri
- Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Carolina Ferro
- Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Rafael Rios
- Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Paola Porras
- Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Carlos Luna
- Pulmonary Division, Department of Medicine, Jose de San Martin Hospital, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Eduardo Gotuzzo
- Hospital Cayetano Heredia and Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jose M Munita
- Center for Antimicrobial Resistance and Microbial Genomics, Houston, Texas.,Genomics and Resistant Microbes (GeRM) group, Clinica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Esteban Nannini
- Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Cesar Carcamo
- Hospital Cayetano Heredia and Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jinnethe Reyes
- Center for Antimicrobial Resistance and Microbial Genomics, Houston, Texas.,Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
| | - Cesar A Arias
- Center for Antimicrobial Resistance and Microbial Genomics, Houston, Texas.,Division of Infectious Diseases, Department of Internal Medicine, Houston, Texas.,Department of Microbiology and Molecular Genetics, UTHealth McGovern Medical School, Houston, Texas.,Molecular Genetics and Antimicrobial Resistance Unit and International Center for Antimicrobial Resistance, Universidad El Bosque, Bogota, Colombia
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30
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Kim T, Kim ES, Park SY, Sung H, Kim MN, Kim SH, Lee SO, Choi SH, Jeong JY, Woo JH, Chong YP, Kim YS. Phenotypic changes of methicillin-resistant Staphylococcus aureus during vancomycin therapy for persistent bacteraemia and related clinical outcome. Eur J Clin Microbiol Infect Dis 2017; 36:1473-1481. [PMID: 28337607 DOI: 10.1007/s10096-017-2956-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/02/2017] [Indexed: 12/13/2022]
Abstract
Persistent bacteraemia (PB) due to methicillin-resistant Staphylococcus aureus (MRSA) that fails to respond to glycopeptide therapy is a well-documented clinical problem. There are limited data on changes in agr functionality, vancomycin susceptibility and heteroresistance during MRSA PB. Thus, the frequency of these changes and their clinical significance remain unclear. Only patients with MRSA PB (≥7 days) from a prospective cohort of S. aureus bacteraemia were included. We collected isogenic paired strains and compared vancomycin MIC, vancomycin heteroresistance, and agr functionality between initial and final blood isolates. We also assessed the clinical outcome. A total of 49 patients had MRSA PB over 22 months. Bacteraemia persisted for a median of 13 days and most patients (98%) received glycopeptide as initial therapy. Among 49 isogenic pairs, only one pair showed a vancomycin MIC increase ≥2-fold by broth microdilution method, and only seven (14%) by E-test. Significant portions of initial isolates had vancomycin heteroresistance (49%) and agr dysfunction (76%). Development of vancomycin heteroresistance during PB occurred in four (16%) among 25 initial vancomycin-susceptible isolates, and acquisition of agr dysfunction occurred in two (16%) among 12 initial agr-functional isolates. Changes in the opposite direction occasionally occurred. These phenotypic changes during PB were not associated with mortality, whereas agr dysfunction of the initial isolates was significantly associated with mortality. During MRSA PB, phenotypic changes of MRSA isolates occurred occasionally under prolonged vancomycin exposure but were not significantly associated with clinical outcome. In contrast, initial agr dysfunction could be a predictor for mortality in MRSA PB.
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Affiliation(s)
- T Kim
- Division of Infectious Diseases, Department of Internal Medicine, Gyeongsang National University Hospital, 79, Gangnam-ro, Jinju, Gyeongsangnam-do, 52727, Republic of Korea
| | - E S Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S Y Park
- Division of Infectious Diseases, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Republic of Korea
| | - H Sung
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - M-N Kim
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - S-H Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S-O Lee
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S-H Choi
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - J-Y Jeong
- Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - J H Woo
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - Y P Chong
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.
| | - Y S Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.
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31
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Cefazolin and Ertapenem, a Synergistic Combination Used To Clear Persistent Staphylococcus aureus Bacteremia. Antimicrob Agents Chemother 2016; 60:6609-6618. [PMID: 27572414 PMCID: PMC5075066 DOI: 10.1128/aac.01192-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 08/08/2016] [Indexed: 11/22/2022] Open
Abstract
Ertapenem and cefazolin were used in combination to successfully clear refractory methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. In addition, recent work has demonstrated activity of combination therapy with beta-lactams from different classes against methicillin-resistant S. aureus (MRSA). The ertapenem-plus-cefazolin combination was evaluated for synergy in vitro and in vivo in a murine skin infection model using an index MSSA bloodstream isolate from a patient in whom persistent bacteremia was cleared with this combination and against a cadre of well-described research strains and clinical strains of MSSA and MRSA. Against the index MSSA bloodstream isolate, ertapenem and cefazolin showed synergy using both checkerboard (fractional inhibitory concentration [FIC] index = 0.375) and time-kill assays. Using a disk diffusion ertapenem potentiation assay, the MSSA isolate showed a cefazolin disk zone increased from 34 to 40 mm. In vitro pharmacokinetic/pharmacodynamic modeling at clinically relevant drug concentrations demonstrated bactericidal activity (>3 log10-CFU/ml reduction) of the combination but bacteriostatic activity of ether drug alone at 48 h. A disk diffusion potentiation assay showed that ertapenem increased the cefazolin zone of inhibition by >3 mm for 34/35 (97%) MSSA and 10/15 (67%) MRSA strains. A murine skin infection model of MSSA showed enhanced activity of cefazolin plus ertapenem compared to monotherapy with these agents. After successful use in clearance of MSSA bacteremia, the combination of ertapenem and cefazolin showed synergy against MSSA in vitro and in vivo. This combination may warrant consideration for future clinical study in MSSA bacteremia.
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Abstract
Infective endocarditis (IE) is a rare, life-threatening disease that has long-lasting effects even among patients who survive and are cured. IE disproportionately affects those with underlying structural heart disease and is increasingly associated with health care contact, particularly in patients who have intravascular prosthetic material. In the setting of bacteraemia with a pathogenic organism, an infected vegetation may form as the end result of complex interactions between invading microorganisms and the host immune system. Once established, IE can involve almost any organ system in the body. The diagnosis of IE may be difficult to establish and a strategy that combines clinical, microbiological and echocardiography results has been codified in the modified Duke criteria. In cases of blood culture-negative IE, the diagnosis may be especially challenging, and novel microbiological and imaging techniques have been developed to establish its presence. Once diagnosed, IE is best managed by a multidisciplinary team with expertise in infectious diseases, cardiology and cardiac surgery. Antibiotic prophylaxis for the prevention of IE remains controversial. Efforts to develop a vaccine that targets common bacterial causes of IE are ongoing, but have not yet yielded a commercially available product.
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Affiliation(s)
- Thomas L Holland
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Room 185 Hanes Building, 315 Trent Drive, Durham, North Carolina 27710, USA
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Larry M Baddour
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Arnold S Bayer
- Department of Medicine, David Geffen School of Medicine at UCLA, Torrance, California, USA
| | - Bruno Hoen
- Department of Infectious Diseases, University Hospital of Pointe-Pitre, Pointe-Pitre, France
| | - Jose M Miro
- Infectious Diseases Service, Hospital Clinic - IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Vance G Fowler
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Room 185 Hanes Building, 315 Trent Drive, Durham, North Carolina 27710, USA
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
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33
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Comparative Efficacies of Tedizolid Phosphate, Linezolid, and Vancomycin in a Murine Model of Subcutaneous Catheter-Related Biofilm Infection Due to Methicillin-Susceptible and -Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2016; 60:5092-6. [PMID: 27297485 DOI: 10.1128/aac.00880-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/07/2016] [Indexed: 12/17/2022] Open
Abstract
Tedizolid, a novel oxazolidinone, exhibits bacteriostatic activity through inhibition of protein synthesis. The efficacies of tedizolid, linezolid, and vancomycin were compared in a murine catheter-related biofilm infection caused by methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) strains engineered for bioluminescence. We observed significantly improved efficacy in terms of decreased S. aureus densities and bioluminescent signals in the tedizolid-treated group versus the linezolid- and vancomycin-treated groups in the model of infection caused by the MSSA and MRSA strains.
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34
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Xiong YQ, Abdelhady W, Tang C'G, Bayer AS. Comparative efficacy of telavancin and daptomycin in experimental endocarditis due to multi-clonotype MRSA strains. J Antimicrob Chemother 2016; 71:2890-4. [PMID: 27353467 DOI: 10.1093/jac/dkw249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/24/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND MRSA strains of clonal complexes (CCs) 5, 8, 30 and 45 are leading causes of complicated endovascular infections associated with suboptimal clinical outcomes. Telavancin is a novel anti-MRSA agent that both inhibits bacterial cell wall synthesis and disrupts membranes by depolarization. METHODS In this study, we compared the in vitro susceptibility and in vivo efficacy of telavancin versus daptomycin in an experimental rabbit infective endocarditis (IE) model caused by four MRSA strains representing each of the above CC types. RESULTS All study strains were susceptible to telavancin (MICs of ≤0.12 mg/L) and daptomycin (MICs of ≤0.5 mg/L). In vitro time-kill analyses revealed that supra-MIC levels of telavancin were effective at preventing regrowth at 24 h of incubation. In the IE animal model for all CC types, treatment with telavancin produced significantly greater reductions in MRSA counts as compared with daptomycin-treated animals in all target tissues. Moreover, telavancin-treated animals had a significantly higher percentage of sterile tissue cultures versus daptomycin-treated animals (e.g. 78%-100% versus 0% sterile vegetations and 100% versus 0%-11% sterile kidneys and spleen, in the telavancin- and daptomycin-treated animals, respectively). CONCLUSIONS These results suggest that telavancin exhibits significantly greater efficacies versus daptomycin in treating experimental IE caused by MRSA clinical isolates across four common CC types.
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Affiliation(s)
- Yan Q Xiong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Wessam Abdelhady
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Chieh 'Genna' Tang
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Arnold S Bayer
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Vancomycin 24-Hour Area under the Curve/Minimum Bactericidal Concentration Ratio as a Novel Predictor of Mortality in Methicillin-Resistant Staphylococcus aureus Bacteremia. Antimicrob Agents Chemother 2016; 60:3070-5. [PMID: 26953202 DOI: 10.1128/aac.02714-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022] Open
Abstract
While previous studies have examined the association between vancomycin (VAN) exposure and MIC with regard to outcomes in methicillin-resistant Staphylococcus aureus bacteremia (MRSA-B), none have explored if a relationship exists with the VAN minimum bactericidal concentration (MBC). The objective of this study was to evaluate the VAN 24-h area under the curve (AUC24)/MBC ratio as a pharmacodynamic predictor of mortality. This retrospective cohort study included patients treated with VAN for MRSA-B with the primary outcome of 30-day all-cause mortality. Data collected included patient demographics, comorbidities, antimicrobial treatment data, therapeutic drug levels, and laboratory and microbiological data. Vancomycin MICs and MBCs were determined by Etest (MIC only) and broth microdilution (BMD). The vancomycin AUC24 was determined by pharmacokinetic maximum a posteriori probability Bayesian (MAP-Bayesian) analysis. The most significant breakpoint for 30-day mortality was determined by classification and regression tree (CART) analysis. The association between pharmacodynamic parameters (VAN AUC24/MICBMD, VAN AUC24/MICEtest, and AUC24/MBCBMD) and mortality were determined by χ(2) and multivariable Poisson regression. Overall mortality in this cohort (n = 53) was 20.8% (n = 11/53), and all corresponding MRSA blood isolates were VAN susceptible (MIC range, 0.5 to 2 μg/ml; MIC50, 1 μg/ml; MIC90, 1 μg/ml). The CART-derived breakpoints for mortality were 176 (VAN AUC24/MBC) and 334 (VAN AUC24/MICBMD). In multivariable analysis, the association between a VAN AUC24/MBC of ≥176 and survival persisted, but VAN AUC24/MICBMD values (≥334 or ≥400) were not associated with improved mortality. In conclusion, VAN AUC24/MBC was a more important predictor of 30-day mortality than VAN AUC24/MIC for MRSA-B.
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Endovascular infections caused by methicillin-resistant Staphylococcus aureus are linked to clonal complex-specific alterations in binding and invasion domains of fibronectin-binding protein A as well as the occurrence of fnbB. Infect Immun 2015; 83:4772-80. [PMID: 26416903 DOI: 10.1128/iai.01074-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022] Open
Abstract
Endovascular infections caused by Staphylococcus aureus involve interactions with fibronectin present as extracellular matrix or surface ligand on host cells. We examined the expression, structure, and binding activity of the two major S. aureus fibronectin-binding proteins (FnBPA, FnBPB) in 10 distinct, methicillin-resistant clinical isolates from patients with either persistent or resolving bacteremia. The persistent bacteremia isolates (n = 5) formed significantly stronger bonds with immobilized fibronectin as determined by dynamic binding measurements performed with atomic force microscopy. Several notable differences were also observed when the results were grouped by clonal complex 5 (CC5) strains (n = 5) versus CC45 strains (n = 5). Fibronectin-binding receptors on CC5 formed stronger bonds with immobilized fibronectin (P < 0.001). The fnbA gene was expressed at higher levels in CC45, whereas fnbB was found in only CC5 isolates. The fnbB gene was not sequenced because all CC45 isolates lacked this gene. Instead, comparisons were made for fnbA, which was present in all 10 isolates. Sequencing of fnbA revealed discrete differences within high-affinity, fibronectin-binding repeats (FnBRs) of FnBPA that included (i) 5-amino-acid polymorphisms in FnBR-9, FnBR-10, and FnBR-11 involving charged or polar side chains, (ii) an extra, 38-amino-acid repeat inserted between FnBR-9 and FnBR-10 exclusively seen in CC45 isolates, and (iii) CC5 isolates had the SVDFEED epitope in FnBR-11 (a sequence shown to be essential for fibronectin binding), while this sequence was replaced in all CC45 isolates with GIDFVED (a motif known to favor host cell invasion at the cost of reduced fibronectin binding). These complementary sequence and binding data suggest that differences in fnbA and fnbB, particularly polymorphisms and duplications in FnBPA, give S. aureus two distinct advantages in human endovascular infections: (i) FnBPs similar to that of CC5 enhance ligand binding and foster initiation of disease, and (ii) CC45-like FnBPs promote cell invasion, a key attribute in persistent endovascular infections.
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Bouchiat C, Moreau K, Devillard S, Rasigade JP, Mosnier A, Geissmann T, Bes M, Tristan A, Lina G, Laurent F, Piroth L, Aissa N, Duval X, Le Moing V, Vandenesch F. Staphylococcus aureus infective endocarditis versus bacteremia strains: Subtle genetic differences at stake. INFECTION GENETICS AND EVOLUTION 2015; 36:524-530. [PMID: 26318542 DOI: 10.1016/j.meegid.2015.08.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/03/2015] [Accepted: 08/23/2015] [Indexed: 11/25/2022]
Abstract
Infective endocarditis (IE)((1)) is a severe condition complicating 10-25% of Staphylococcus aureus bacteremia. Although host-related IE risk factors have been identified, the involvement of bacterial features in IE complication is still unclear. We characterized strictly defined IE and bacteremia isolates and searched for discriminant features. S. aureus isolates causing community-acquired, definite native-valve IE (n=72) and bacteremia (n=54) were collected prospectively as part of a French multicenter cohort. Phenotypic traits previously reported or hypothesized to be involved in staphylococcal IE pathogenesis were tested. In parallel, the genotypic profiles of all isolates, obtained by microarray, were analyzed by discriminant analysis of principal components (DAPC)((2)). No significant difference was observed between IE and bacteremia strains, regarding either phenotypic or genotypic univariate analyses. However, the multivariate statistical tool DAPC, applied on microarray data, segregated IE and bacteremia isolates: IE isolates were correctly reassigned as such in 80.6% of the cases (C-statistic 0.83, P<0.001). The performance of this model was confirmed with an independent French collection IE and bacteremia isolates (78.8% reassignment, C-statistic 0.65, P<0.01). Finally, a simple linear discriminant function based on a subset of 8 genetic markers retained valuable performance both in study collection (86.1%, P<0.001) and in the independent validation collection (81.8%, P<0.01). We here show that community-acquired IE and bacteremia S. aureus isolates are genetically distinct based on subtle combinations of genetic markers. This finding provides the proof of concept that bacterial characteristics may contribute to the occurrence of IE in patients with S. aureus bacteremia.
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Affiliation(s)
- Coralie Bouchiat
- Laboratoire de Bactériologie, Centre de Biologie Est, Hospices Civils de Lyon, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France; CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Karen Moreau
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France
| | - Sébastien Devillard
- Université de Lyon, Université Lyon 1, CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622 Villeurbanne, France
| | - Jean-Philippe Rasigade
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Amandine Mosnier
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France
| | - Tom Geissmann
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France
| | - Michèle Bes
- Laboratoire de Bactériologie, Centre de Biologie Est, Hospices Civils de Lyon, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France; CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Anne Tristan
- Laboratoire de Bactériologie, Centre de Biologie Est, Hospices Civils de Lyon, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France; CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Gérard Lina
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Frédéric Laurent
- CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France
| | - Lionel Piroth
- Service de Maladies Infectieuses, CHU de Dijon, 14 rue Gaffarel, 21079 Dijon Cedex, France
| | - Nejla Aissa
- Laboratoire de Bactériologie, CHU de Nancy, 29 avenue du Maréchal de Lattre de Tassigny, 54035 Nancy, France
| | - Xavier Duval
- Centre d'Investigation Clinique, Inserm CIC 1425, IAME, Hôpital Bichat-Claude Bernard, 46 rue Henri Huchard, 75018 Paris, France
| | - Vincent Le Moing
- Service des Maladies Infectieuses et Tropicales, CHU de Montpellier, Hôpital Gui de Chauliac, 34000 Montpellier, France
| | - François Vandenesch
- Laboratoire de Bactériologie, Centre de Biologie Est, Hospices Civils de Lyon, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France; CIRI, International Center for Infectiology Research, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS UMR5308, 7 rue Guillaume Paradin, 69008 Lyon, France; Centre National de Référence des Staphylocoques, 59 Boulevard Louis Pinel, 69677 Bron Cedex, France.
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Persistent Staphylococcus aureus isolates from two independent cases of bacteremia display increased bacterial fitness and novel immune evasion phenotypes. Infect Immun 2015; 83:3311-24. [PMID: 26056388 PMCID: PMC4496624 DOI: 10.1128/iai.00255-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/29/2015] [Indexed: 01/26/2023] Open
Abstract
Staphylococcus aureus bacteremia cases are complicated by bacterial persistence and treatment failure despite the confirmed in vitro susceptibility of the infecting strain to administered antibiotics. A high incidence of methicillin-resistant S. aureus (MRSA) bacteremia cases are classified as persistent and are associated with poorer patient outcomes. It is still unclear how S. aureus evades the host immune system and resists antibiotic treatment for the prolonged duration of a persistent infection. In this study, the genetic changes and associated phenotypic traits specific to S. aureus persistent bacteremia were identified by comparing temporally dispersed isolates from persistent infections (persistent isolates) originating from two independent persistent S. aureus bacteremia cases with the initial infection isolates and with three resolved S. aureus bacteremia isolates from the same genetic background. Several novel traits were associated specifically with both independent sets of persistent S. aureus isolates compared to both the initial isolates and the isolates from resolved infections (resolved isolates). These traits included (i) increased growth under nutrient-poor conditions; (ii) increased tolerance of iron toxicity; (iii) higher expression of cell surface proteins involved in immune evasion and stress responses; and (iv) attenuated virulence in a Galleria mellonella larva infection model that was not associated with small-colony variation or metabolic dormancy such as had been seen previously. Whole-genome sequence analysis identified different single nucleotide mutations within the mprF genes of all the isolates with the adaptive persistence traits from both independent cases. Overall, our data indicate a novel role for MprF function during development of S. aureus persistence by increasing bacterial fitness and immune evasion.
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39
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Abdelhady W, Chen L, Bayer AS, Seidl K, Yeaman MR, Kreiswirth BN, Xiong YQ. Early agr activation correlates with vancomycin treatment failure in multi-clonotype MRSA endovascular infections. J Antimicrob Chemother 2015; 70:1443-52. [PMID: 25564565 DOI: 10.1093/jac/dku547] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/03/2014] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVES Persistent MRSA infections are especially relevant to endovascular infections and correlate with suboptimal outcomes. However, the virulence signatures of Staphylococcus aureus that drive such persistence outcomes are not well defined. In the current study, we investigated correlations between accessory gene regulator (agr) activation and the outcome of vancomycin treatment in an experimental model of infective endocarditis (IE) due to MRSA strains with different agr and clonal complex (CC) types. METHODS Twelve isolates with the four most common MRSA CC and agr types (CC5-agr II, CC8-agr I, CC30-agr III and CC45-agr I) were evaluated for heterogeneous vancomycin-intermediate S. aureus (hVISA), agr function, agrA and RNAIII transcription, agr locus sequences, virulence and response to vancomycin in the IE model. RESULTS Early agr RNAIII activation (beginning at 2 h of growth) in parallel with strong δ-haemolysin production correlated with persistent outcomes in the IE model following vancomycin therapy. Importantly, such treatment failures occurred across the range of CC/agr types studied. In addition, these MRSA strains: (i) were vancomycin susceptible in vitro; (ii) were not hVISA or vancomycin tolerant; and (iii) did not evolve hVISA phenotypes or perturbed δ-haemolysin activity in vivo following vancomycin therapy. Moreover, agr locus sequence analyses revealed no common point mutations that correlated with either temporal RNAIII transcription or vancomycin treatment outcomes, encompassing different CC and agr types. CONCLUSIONS These data suggest that temporal agr RNAIII activation and agr functional profiles may be useful biomarkers to predict the in vivo persistence of endovascular MRSA infections despite vancomycin therapy.
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Affiliation(s)
- Wessam Abdelhady
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Liang Chen
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Arnold S Bayer
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kati Seidl
- University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michael R Yeaman
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Barry N Kreiswirth
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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40
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Oosthuysen WF, Orth H, Lombard C, Sinha B, Wasserman E. In vitro characterization of representative clinical South African Staphylococcus aureus isolates from various clonal lineages. New Microbes New Infect 2014; 2:115-22. [PMID: 25356356 PMCID: PMC4184580 DOI: 10.1002/nmi2.53] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/06/2014] [Accepted: 05/14/2014] [Indexed: 01/11/2023] Open
Abstract
Data concerning the virulence and pathogenesis of South African strains of Staphylococcus aureus are limited. We investigated host–pathogen interactions of randomly selected clinical S. aureus isolates representing various clones. We characterized the ability of isolates to adhere to fibronectin, fibrinogen, collagens IV and VI, to invade host cells and to induce cell death in vitro. We analysed the possible association of these results with characteristics such as methicillin resistance, Panton–Valentine leucocidin (PVL) positivity and clonality. The S. aureus isolates displayed diversity in their abilities to adhere to various human ligands. All isolates were highly invasive except for ST121. PVL-negative isolates were significantly more invasive than the PVL-positive isolates (p 0.004). Isolates of CC5, CC30 and CC121 were non-cytotoxic, whereas isolates of CC22, CC8, CC15, CC45 and CC88 were very cytotoxic. No statistical association was identified between cell death and methicillin resistance, bacterial PVL status, clonality or patient HIV status. The vast majority of isolates were invasive and induced significant cell death. PVL-negative isolates were more invasive than PVL-positive isolates, while methicillin-resistant isolates were not found to be more invasive or cytotoxic than methicillin-susceptible isolates.
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Affiliation(s)
- W F Oosthuysen
- Division of Medical Microbiology, Stellenbosch University, Tygerberg Hospital Cape Town, South Africa
| | - H Orth
- Division of Medical Microbiology, Stellenbosch University, Tygerberg Hospital Cape Town, South Africa ; National Health Laboratory Services, Microbiology Laboratory, Tygerberg Academic Complex Cape Town, South Africa
| | - C Lombard
- Biostatistics Unit, Medical Research Council Cape Town, South Africa
| | - B Sinha
- University Medical Centre Groningen Groningen, The Netherlands
| | - E Wasserman
- Division of Medical Microbiology, Stellenbosch University, Tygerberg Hospital Cape Town, South Africa ; Pathcare Laboratories Cape Town, South Africa
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Gasch O, Camoez M, Dominguez MA, Padilla B, Pintado V, Almirante B, Martín-Gandul C, López-Medrano F, de Gopegui ER, Ramón Blanco J, García-Pardo G, Calbo E, Horcajada JP, Granados A, Jover-Sáenz A, Dueñas C, Pujol M. Lack of association between genotypes and haematogenous seeding infections in a large cohort of patients with methicillin-resistant Staphylococcus aureus bacteraemia from 21 Spanish hospitals. Clin Microbiol Infect 2014; 20:361-7. [PMID: 23991832 DOI: 10.1111/1469-0691.12330] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 02/05/2023]
Abstract
There is increasing concern regarding the association between certain methicillin-resistant Staphylococcus aureus (MRSA) genotypes and poor clinical outcome. To assess this issue, a large cohort of 579 subjects with MRSA bacteraemia was prospectively followed from June 2008 to December 2009, in 21 hospitals in Spain. Epidemiology, clinical data, therapy, and outcome were recorded. All MRSA strains were analysed in a central laboratory. Presence of a haematogenous seeding infection was the dependent variable in an adjusted logistic regression model. Of the 579 patients included in the study, 84 (15%) had haematogenous seeding infections. Microdilution vancomycin median MIC (IQR) was 0.73 (0.38-3) mg/L. Most MRSA isolates (n = 371; 67%) belonged to Clonal Complex 5 (CC5) and carried an SCCmec element type IV and agr type 2. Isolates belonging to ST8-agr1-SCCmecIV, ST22-agr1-SCCmecIV and ST228-agr2-SCCmecI--a single locus variant of ST5--accounted for 8%, 9% and 9% of the isolates, respectively. After adjusting by clinical variables, any of the clones was associated with increased risk of haematogenous seeding infections. Higher vancomycin MIC was not identified as an independent risk factor, either. In contrast, persistent bacteraemia (OR 4.2; 2.3-7.8) and non-nosocomial acquisition (3.0; 1.7-5.6) were associated with increased risk.
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Affiliation(s)
- O Gasch
- Department of Infectious Diseases, Hospital Universitari de Bellvitge, Barcelona, Spain
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42
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Genome Sequences of Sequence Type 45 (ST45) Persistent Methicillin-Resistant Staphylococcus aureus (MRSA) Bacteremia Strain 300-169 and ST45 Resolving MRSA Bacteremia Strain 301-188. GENOME ANNOUNCEMENTS 2014; 2:2/2/e00174-14. [PMID: 24625873 PMCID: PMC3953194 DOI: 10.1128/genomea.00174-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (positive blood cultures after ≥7 days) represents a challenging subset of invasive MRSA infections. The comparison of genome sequences of persistent (300-169) and resolving (301-188) MRSA bacteremia isolates with similar genetic background (sequence type 45 [ST45]) will help us to better understand underlying mechanisms of persistent MRSA bacteremia.
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Chong YP, Park KH, Kim ES, Kim MN, Kim SH, Lee SO, Choi SH, Jeong JY, Woo JH, Kim YS. Association of mannose-binding lectin 2 gene polymorphisms with persistent Staphylococcus aureus bacteremia. PLoS One 2014; 9:e89139. [PMID: 24595015 PMCID: PMC3942407 DOI: 10.1371/journal.pone.0089139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 01/21/2014] [Indexed: 11/18/2022] Open
Abstract
Objectives Mannose-binding lectin (MBL) is an important component of innate immunity. Structural and promoter polymorphisms in the MBL2 gene that are responsible for low MBL levels are associated with susceptibility to infectious diseases. The objective of this study was to investigate the association of serum MBL levels and MBL2 polymorphisms with persistent Staphylococcus aureus bacteremia (SAB) in adult Korean patients. Methods We conducted a case-control study nested in a prospective cohort of patients with SAB. The study compared 41 patients with persistent bacteremia (≥7 days) and 46 patients with resolving bacteremia (<3 days). In each subject, we genotyped six single-nucleotide polymorphisms in the promoter region (alleles H/L, X/Y, and P/Q) and exon 1 (alleles A/B, A/C, and A/D) of the MBL2 gene and measured serum MBL concentrations. We also compared MBL2 genotypes between SAB patients and healthy people. Results Patients with persistent bacteremia were significantly more likely to have low/deficient MBL-producing genotypes and resultant low serum MBL levels, than were patients with resolving bacteremia (P = 0.019 and P = 0.012, respectively). Independent risk factors for persistent bacteremia were metastatic infection (adjusted odds ratio [aOR], 34.7; 95% confidence interval [CI], 12.83–196.37; P = 0.003), methicillin resistance (aOR, 4.10; 95% CI, 3.19–29.57; P = 0.025), and low/deficient MBL-producing genotypes (aOR, 7.64; 95% CI, 4.12–63.39; P = 0.003). Such genotypes were significantly more common in patients with persistent bacteremia than in healthy people (OR, 2.09; 95% CI, 1.03–4.26; P = 0.040). Conclusions This is the first demonstration of an association of low MBL levels and MBL2 polymorphisms responsible for low or deficient MBL levels with persistent SAB. A combination of factors, including clinical and microbiological characteristics and host defense factors such as MBL levels, may together contribute to the development of persistent SAB.
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Affiliation(s)
- Yong Pil Chong
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Ki-Ho Park
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Eun Sil Kim
- Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Mi-Na Kim
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung-Han Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-Oh Lee
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-Ho Choi
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jin-Yong Jeong
- Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Asan Institute of Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jun Hee Woo
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yang Soo Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
- * E-mail:
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Abdelhady W, Bayer AS, Seidl K, Moormeier DE, Bayles KW, Cheung A, Yeaman MR, Xiong YQ. Impact of vancomycin on sarA-mediated biofilm formation: role in persistent endovascular infections due to methicillin-resistant Staphylococcus aureus. J Infect Dis 2014; 209:1231-40. [PMID: 24403556 DOI: 10.1093/infdis/jiu007] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Staphylococcus aureus is the most common cause of endovascular infections. The staphylococcal accessory regulator A locus (sarA) is a major virulence determinant that may potentially impact methicillin-resistant S. aureus (MRSA) persistence in such infections via its influence on biofilm formation. METHODS Two healthcare-associated MRSA isolates from patients with persistent bacteremia and 2 prototypical community-acquired MRSA strains, as well as their respective isogenic sarA mutants, were studied for in vitro biofilm formation, fibronectin-binding capacity, autolysis, and protease and nuclease activities. These assays were done in the presence or absence of sub-minimum inhibitory concentrations (MICs) of vancomycin. In addition, these strain pairs were compared for intrinsic virulence and responses to vancomycin therapy in experimental infective endocarditis, a prototypical biofilm model. RESULTS All sarA mutants displayed significantly reduced biofilm formation and binding to fibronectin but increased protease production in vitro, compared with their respective parental strains. Interestingly, exposure to sub-MICs of vancomycin significantly promoted biofilm formation and fibronectin-binding in parental strains but not in sarA mutants. In addition, all sarA mutants became exquisitely susceptible to vancomycin therapy, compared with their respective parental strains, in the infective endocarditis model. CONCLUSIONS These observations suggest that sarA activation is important in persistent MRSA endovascular infection, potentially in the setting of biofilm formation.
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Affiliation(s)
- Wessam Abdelhady
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
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Population structure and characterisation of Staphylococcus aureus from bacteraemia at multiple hospitals in China: association between antimicrobial resistance, toxin genes and genotypes. Int J Antimicrob Agents 2013; 42:211-9. [PMID: 23871455 DOI: 10.1016/j.ijantimicag.2013.04.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 04/26/2013] [Accepted: 04/26/2013] [Indexed: 11/23/2022]
Abstract
Staphylococcus aureus from bacteraemia at multiple hospitals in China were genetically characterised to improve understanding of its epidemiology. A total of 236 consecutive, non-duplicate S. aureus bacteraemia isolates were collected at 16 Chinese hospitals. Isolates were characterised by antimicrobial resistance, 19 toxin genes, agr alleles, multilocus sequence typing and spa typing. The prevalence of meticillin-resistant S. aureus (MRSA) was 47.5% (112/236). Forty-two sequence types (STs) and 63 spa types were identified, including 14 STs and 14 spa types for MRSA. Clonal complex (CC) 8, CC5, ST7 and CC188 accounted for 67.4% of the isolates. ST239-t030/t037-SCCmecIII-agrI was the predominant MRSA genotype (50%), followed by ST5-t002/t570-SCCmecII-agrII (8%). A vancomycin MIC ≥ 1mg/L was detected significantly more often in ST5-SCCmecII and ST239-t037-SCCmecIII, whereas rifampicin resistance was overwhelmingly associated with ST239-t030-SCCmecIII (P<0.001). Oxacillin MICs were relatively low for ST59-MRSA. Major genotypes of meticillin-susceptible S. aureus (MSSA) were ST7-t091/t796-agrI (16.1%), ST188-t189-agrI (12.1%) and ST398-t571/t034-agrI (5.6%). Toxin genes were identified in 95.8% of isolates and formed 89 toxin gene profiles. The toxin genes sea, selk, selq and sell were significantly more common in MRSA, whilst tsst-1, seb, sed, selm, seln, selp and selj were more prevalent in MSSA (P<0.001). The pvl gene was more commonly detected in CC59, whereas tsst-1 was more frequent in CC15, CC188 and ST398 (P<0.001). The major genotypes were associated with specific antimicrobial resistance and toxin gene profiles.
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Chong YP, Park SJ, Kim HS, Kim ES, Kim MN, Park KH, Kim SH, Lee SO, Choi SH, Jeong JY, Woo JH, Kim YS. Persistent Staphylococcus aureus bacteremia: a prospective analysis of risk factors, outcomes, and microbiologic and genotypic characteristics of isolates. Medicine (Baltimore) 2013; 92:98-108. [PMID: 23429353 PMCID: PMC4553980 DOI: 10.1097/md.0b013e318289ff1e] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Persistent Staphylococcus aureus bacteremia (SAB) that fails to respond to appropriate antibiotic therapy is associated with poor outcomes. Comprehensive prospective studies on risk factors and outcomes of persistent bacteremia are limited. We investigated outcomes and risk factors encompassing clinical, pharmacokinetic, microbiologic, and genotypic characteristics associated with persistent bacteremia using a case-control study nested in a prospective cohort of patients with SAB at a tertiary-care hospital from August 2008 through September 2010. We compared the clinical characteristics, management, and outcomes of patients with persistent bacteremia (≥7 d) with controls with resolving bacteremia (<3 d). To detect associations between microbiologic and genotypic characteristics of methicillin-resistant S. aureus (MRSA) isolates and persistent bacteremia, we determined the heteroresistance phenotype, SCCmec type, agr genotype and functionality, multilocus sequence typing, and presence of 41 virulence genes. Our cohort consisted of 483 patients; 76 (15.7%) had persistent bacteremia, 212 (43.5%) had resolving bacteremia. In the multivariate analysis, independent risk factors associated with persistent bacteremia were community-onset bacteremia (odds ratio [OR], 2.91; 95% confidence interval [CI], 1.24-6.87), bone and joint infection (OR, 5.26; 95% CI, 1.45-19.03), central venous catheter-related infection (OR, 3.36; 95% CI, 1.47-7.65), metastatic infection (OR, 36.22; 95% CI, 12.71-103.23), and methicillin resistance (OR, 16.99; 95% CI, 5.53-52.15). For patients with eradicable foci, delay (>3 d) in the removal of the infection focus was significantly associated with persistent bacteremia (OR, 2.18; 95% CI, 1.05-4.55). There were no significant associations of persistent bacteremia with high vancomycin minimal inhibitory concentration, vancomycin heteroresistance, and microbiologic/genotypic characteristics of MRSA isolates. However, initial vancomycin trough level <15 mg/L was an independent risk factor for persistent MRSA bacteremia (OR, 4.25; 95% CI, 1.51-11.96) in the multivariate analysis. Clinical outcomes were significantly worse for patients with persistent bacteremia. Relapse of bacteremia and attributable mortality within 12 weeks after SAB were significantly higher in patients with persistent bacteremia than in those with resolving bacteremia (9.2% [7/76] vs. 2.4% [5/212], p = 0.02 and 21.1% [16/76] vs. 9.4% [20/212], p = 0.009, respectively). In conclusion, patients with SAB should be given early aggressive treatment strategies, including early source control and maintenance of a vancomycin trough level ≥15 mg/L, to reduce the risk of persistent bacteremia.
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Affiliation(s)
- Yong Pil Chong
- From the Department of Infectious Diseases (YPC, KHP, SHK, SOL, SHC, JHW, YSK) and Department of Laboratory Medicine (MNK), Asan Medical Center, University of Ulsan College of Medicine, Center for Antimicrobial Resistance and Microbial Genetics (SJP, HSK, ESK, JYJ, YSK), Seoul, Republic of Korea
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Reduced vancomycin susceptibility in an in vitro catheter-related biofilm model correlates with poor therapeutic outcomes in experimental endocarditis due to methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2013; 57:1447-54. [PMID: 23295925 DOI: 10.1128/aac.02073-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is the most common cause of endovascular infections, including catheter sepsis and infective endocarditis (IE). Vancomycin (VAN) is the primary choice for treatment of methicillin-resistant S. aureus (MRSA) infections. However, high rates of VAN treatment failure in MRSA infections caused by VAN-susceptible strains have been increasingly reported. Biofilm-associated MRSA infections are especially prone to clinical antibiotic failure. The present studies examined potential relationships between MRSA susceptibility to VAN in biofilms in vitro and nonsusceptibility to VAN in endovascular infection in vivo. Using 10 "VAN-susceptible" MRSA bloodstream isolates previously investigated for VAN responsiveness in experimental IE, we studied the mechanism(s) of such in vivo VAN resistance, including: (i) VAN binding to MRSA organisms; (ii) the impact of VAN on biofilm formation and biofilm composition; (iii) VAN efficacy in an in vitro catheter-related biofilm model; (iv) effects on cell wall thickness. As a group, the five strains previously categorized as VAN nonresponders (non-Rsp) in the experimental IE model differed from the five responders (Rsp) in terms of lower VAN binding, increased biofilm formation, higher survival in the presence of VAN within biofilms in the presence or absence of catheters, and greater biofilm reduction upon proteinase K treatment. Interestingly, sub-MICs of VAN significantly promoted biofilm formation only in the non-Rsp isolates. Cell wall thickness was similar among all MRSA strains. These results suggest that sublethal VAN levels that induce biofilm formation and reduce efficacy of VAN in the in vitro catheter-associated biofilms may contribute to suboptimal treatment outcomes for endovascular infections caused by "VAN-susceptible" MRSA strains.
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agr dysfunction and persistent methicillin-resistant Staphylococcus aureus bacteremia in patients with removed eradicable foci. Infection 2012; 41:111-9. [DOI: 10.1007/s15010-012-0348-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 09/25/2012] [Indexed: 01/25/2023]
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Mishra NN, Bayer AS, Moise PA, Yeaman MR, Sakoulas G. Reduced susceptibility to host-defense cationic peptides and daptomycin coemerge in methicillin-resistant Staphylococcus aureus from daptomycin-naive bacteremic patients. J Infect Dis 2012; 206:1160-7. [PMID: 22904338 DOI: 10.1093/infdis/jis482] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We hypothesized that, for methicillin-resistant Staphylococcus aureus (MRSA), in vitro daptomycin susceptibility could be influenced by exposures to endogenous host defense peptides (HDPs) prior to clinical exposure to daptomycin. METHODS Two endovascular HDPs were used: thrombin-induced platelet microbicidal protein (tPMP) and human neutrophil defensin-1 (hNP-1) from neutrophils. Forty-seven unique MRSA isolates obtained from bacteremic patients in multicenter prospective clinical trials were studied. Clinical characteristics, microbiologic parameters, prior vancomycin therapy, and susceptibilities to tPMP, hNP-1, and daptomycin were compared using univariate and multivariate analyses. RESULTS All strains were daptomycin susceptible. Daptomycin minimum inhibitory concentrations (MICs) were inversely related to in vitro tPMP (but not hNP-1) killing. Strains with a daptomycin MIC of 1 mg/L exhibited significantly less killing by tPMP, compared with strains with an MIC of ≤ 0.5 mg/L. Prior vancomycin therapy did not influence this relationship. Regression tree modeling confirmed that reduced tPMP-induced killing in vitro was the strongest predictor of higher daptomycin MICs within the daptomycin-susceptible range. CONCLUSIONS Among daptomycin-susceptible MRSA isolates from patients who had never received daptomycin, higher daptomycin MICs tracked with increased resistance to killing by platelet-derived but not neutrophil-derived HDPs. These findings support the notion that endogenous exposure of MRSA to specific HDPs may play a role in selecting strains with an intrinsically higher daptomycin MIC phenotype.
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Pharmacodynamic evaluation of the activity of antibiotics against hemin- and menadione-dependent small-colony variants of Staphylococcus aureus in models of extracellular (broth) and intracellular (THP-1 monocytes) infections. Antimicrob Agents Chemother 2012; 56:3700-11. [PMID: 22564838 DOI: 10.1128/aac.00285-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus small-colony variants (SCVs) persist intracellularly, which may contribute to persistence/recurrence of infections and antibiotic failure. We have studied the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent SCVs, respectively) of the COL methicillin-resistant S. aureus (MRSA) strain and the antibiotic pharmacodynamic profile against extracellular (broth) and intracellular (human THP-1 monocytes) bacteria. Compared to the parental strain, SCVs showed slower extracellular growth (restored upon medium supplementation with menadione or hemin), reduced phagocytosis, and, for the menD SCV, lower intracellular counts at 24 h postinfection. Against extracellular bacteria, daptomycin, gentamicin, rifampin, moxifloxacin, and oritavancin showed similar profiles of activity against all strains, with a static effect obtained at concentrations close to their MICs and complete eradication as maximal effect. In contrast, vancomycin was not bactericidal against SCVs. Against intracellular bacteria, concentration-effect curves fitted sigmoidal regressions for vancomycin, daptomycin, gentamicin, and rifampin (with maximal effects lower than a 2-log decrease in CFU) but biphasic regressions (with a maximal effect greater than a 3-log decrease in CFU) for moxifloxacin and oritavancin, suggesting a dual mode of action against intracellular bacteria. For all antibiotics, these curves were indistinguishable between the strains investigated, except for the menD mutant, which systematically showed a lower amplitude of the concentration-effect response, with markedly reduced minimal efficacy (due to slower growth) but no change in maximal efficacy. The data therefore show that the maximal efficacies of antibiotics are similar against normal-phenotype and menadione- and hemin-dependent strains despite their different intracellular fates, with oritavancin, and to some extent moxifloxacin, being the most effective.
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