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Zhang F, Wang B, Liu S, Chen Y, Lin Y, Liu Z, Zhang X, Yu B. Bacillus subtilis revives conventional antibiotics against Staphylococcus aureus osteomyelitis. Microb Cell Fact 2021; 20:102. [PMID: 34001083 PMCID: PMC8130150 DOI: 10.1186/s12934-021-01592-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/08/2021] [Indexed: 11/28/2022] Open
Abstract
As treatment of Staphylococcus aureus (S. aureus) osteomyelitis is often hindered by the development of antibiotic tolerance, novel antibacterial therapeutics are required. Here we found that the cell-free supernatant of Bacillus subtilis (B. subtilis CFS) killed planktonic and biofilm S. aureus, and increased S. aureus susceptibility to penicillin and gentamicin as well. Further study showed that B. subtilis CFS suppressed the expression of the genes involved in adhesive molecules (Cna and ClfA), virulence factor Hla, quorum sensing (argA, argB and RNAIII) and biofilm formation (Ica and sarA) in S. aureus. Additionally, our data showed that B. subtilis CFS changed the membrane components and increased membrane permeabilization of S. aureus. Finally, we demonstrated that B. subtilis CFS increased considerably the susceptibility of S. aureus to penicillin and effectively reduced S. aureus burdens in a mouse model of implant-associated osteomyelitis. These findings support that B. subtilis CFS may be a potential resistance-modifying agent for β-lactam antibiotics against S. aureus.
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Affiliation(s)
- Fan Zhang
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Bowei Wang
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China
| | - Shiluan Liu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuhui Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yihuang Lin
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zixian Liu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xianrong Zhang
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China. .,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Bin Yu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No.1838 North of Guangzhou Avenue, Guangzhou, 510515, Guangdong, China. .,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Abstract
We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms.
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Zayed Y, Swaid B, Gupta R, Haykal T, Osterholzer D. Unrecognized staphylococcal vertebral osteomyelitis leading to fatal outcome in a previously healthy patient. Clin Case Rep 2019; 7:229-230. [PMID: 30656049 PMCID: PMC6333079 DOI: 10.1002/ccr3.1864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/20/2018] [Accepted: 09/21/2018] [Indexed: 12/17/2022] Open
Abstract
New onset low back pain which is recalcitrant to usual treatment should be evaluated aggressively even in the absence of fever or neurologic deficits. Corticosteroids given for back pain will accelerate occult spinal infection and may mask symptomatology leading to more severe disease.
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Affiliation(s)
- Yazan Zayed
- Department of Internal Medicine, Hurley Medical CenterMichigan State UniversityFlintMichigan
| | - Bakr Swaid
- Department of Internal Medicine, Hurley Medical CenterMichigan State UniversityFlintMichigan
| | - Rahul Gupta
- Department of Internal Medicine, Hurley Medical CenterMichigan State UniversityFlintMichigan
| | - Tarek Haykal
- Department of Internal Medicine, Hurley Medical CenterMichigan State UniversityFlintMichigan
| | - Danielle Osterholzer
- Department of Internal Medicine, Hurley Medical CenterMichigan State UniversityFlintMichigan
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Idelevich EA, Kriegeskorte A, Schleimer N, Peters G, von Eiff C, Becker K. In Vitro Susceptibility of Clinical Staphylococcus aureus Small-Colony Variants to β-Lactam and Non-β-Lactam Antibiotics. Antimicrob Agents Chemother 2018; 62:e02532-17. [PMID: 29378720 PMCID: PMC5913952 DOI: 10.1128/aac.02532-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/19/2018] [Indexed: 02/08/2023] Open
Abstract
The Staphylococcus aureus small-colony variant (SCV) phenotype has been associated with relapsing and antibiotic-refractory infections. However, little is known about the activities of antibiotics on clinical SCVs. Here, we demonstrated that SCVs without detectable auxotrophies were at least as susceptible to most β-lactam and non-β-lactam antibiotics in vitro as their corresponding clonally identical strains with a normal phenotype. After prolonged incubation, a regrowth phenomenon has been observed in gradient diffusion inhibition zones irrespective of the strains' phenotype.
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Affiliation(s)
- Evgeny A Idelevich
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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García-Betancur JC, Goñi-Moreno A, Horger T, Schott M, Sharan M, Eikmeier J, Wohlmuth B, Zernecke A, Ohlsen K, Kuttler C, Lopez D. Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus. eLife 2017; 6. [PMID: 28893374 PMCID: PMC5595439 DOI: 10.7554/elife.28023] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 08/09/2017] [Indexed: 12/13/2022] Open
Abstract
A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types. While in hospital, patients can be unwittingly exposed to bacteria that can cause disease. These hospital-associated bacteria can lead to potentially life-threatening infections that may also complicate the treatment of the patients’ existing medical conditions. Staphylococcus aureus is one such bacterium, and it can cause several types of infection including pneumonia, blood infections and long-term infections of prosthetic devices. It is thought that S. aureus is able to cause so many different types of infection because it is capable of colonizing distinct tissues and organs in various parts of the body. Understanding the biological processes that drive the different infections is crucial to improving how these infections are treated. S. aureus lives either as an independent, free-swimming cell or as part of a community known as a biofilm. These different lifestyles dictate the type of infection the bacterium can cause, with free-swimming cells producing toxins that contribute to intense, usually short-lived, infections and biofilms promoting longer-term infections that are difficult to eradicate. However, it is not clear how a population of S. aureus cells chooses to adopt a particular lifestyle and whether there are any environmental signals that influence this decision. Here, Garcia-Betancur et al. found that S. aureus populations contain small groups of cells that have already specialized into a particular lifestyle. These groups of cells collectively influence the choice made by other cells in the population. While both lifestyles will be represented in the population, environmental factors influence the numbers of cells that initially adopt each type of lifestyle, which ultimately affects the choice made by the rest of the population. For example, if the bacteria colonize a tissue or organ that contains high levels of magnesium ions, the population is more likely to form biofilms. In the future, the findings of Garcia-Betancur et al. may help us to predict how an infection may develop in a particular patient, which may help to diagnose the infection more quickly and allow it to be treated more effectively.
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Affiliation(s)
- Juan-Carlos García-Betancur
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany.,Research Center for Infectious Diseases, University of Würzburg, Würzburg, Germany
| | - Angel Goñi-Moreno
- School of Computing Science, Newcastle University, Newcastle, United Kingdom
| | - Thomas Horger
- Department of Mathematics, Technical University of Munich, Garching, Germany
| | - Melanie Schott
- Institute of Clinical Biochemistry and Pathobiochemistry, University Hospital Würzburg, Würzburg, Germany
| | - Malvika Sharan
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Julian Eikmeier
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany.,Research Center for Infectious Diseases, University of Würzburg, Würzburg, Germany
| | - Barbara Wohlmuth
- Department of Mathematics, Technical University of Munich, Garching, Germany
| | - Alma Zernecke
- Institute of Clinical Biochemistry and Pathobiochemistry, University Hospital Würzburg, Würzburg, Germany
| | - Knut Ohlsen
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Christina Kuttler
- Department of Mathematics, Technical University of Munich, Garching, Germany
| | - Daniel Lopez
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany.,Research Center for Infectious Diseases, University of Würzburg, Würzburg, Germany.,National Center for Biotechnology, Madrid, Spain
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