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Hoffmann A, Steffens U, Maček B, Franz-Wachtel M, Nieselt K, Harbig TA, Scherlach K, Hertweck C, Sahl HG, Bierbaum G. The unusual mode of action of the polyketide glycoside antibiotic cervimycin C. mSphere 2024; 9:e0076423. [PMID: 38722162 DOI: 10.1128/msphere.00764-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 03/28/2024] [Indexed: 05/30/2024] Open
Abstract
Cervimycins A-D are bis-glycosylated polyketide antibiotics produced by Streptomyces tendae HKI 0179 with bactericidal activity against Gram-positive bacteria. In this study, cervimycin C (CmC) treatment caused a spaghetti-like phenotype in Bacillus subtilis 168, with elongated curved cells, which stayed joined after cell division, and exhibited a chromosome segregation defect, resulting in ghost cells without DNA. Electron microscopy of CmC-treated Staphylococcus aureus (3 × MIC) revealed swollen cells, misshapen septa, cell wall thickening, and a rough cell wall surface. Incorporation tests in B. subtilis indicated an effect on DNA biosynthesis at high cervimycin concentrations. Indeed, artificial downregulation of the DNA gyrase subunit B gene (gyrB) increased the activity of cervimycin in agar diffusion tests, and, in high concentrations (starting at 62.5 × MIC), the antibiotic inhibited S. aureus DNA gyrase supercoiling activity in vitro. To obtain a more global view on the mode of action of CmC, transcriptomics and proteomics of cervimycin treated versus untreated S. aureus cells were performed. Interestingly, 3 × MIC of cervimycin did not induce characteristic responses, which would indicate disturbance of the DNA gyrase activity in vivo. Instead, cervimycin induced the expression of the CtsR/HrcA heat shock operon and the expression of autolysins, exhibiting similarity to the ribosome-targeting antibiotic gentamicin. In summary, we identified the DNA gyrase as a target, but at low concentrations, electron microscopy and omics data revealed a more complex mode of action of cervimycin, which comprised induction of the heat shock response, indicating protein stress in the cell.IMPORTANCEAntibiotic resistance of Gram-positive bacteria is an emerging problem in modern medicine, and new antibiotics with novel modes of action are urgently needed. Secondary metabolites from Streptomyces species are an important source of antibiotics, like the cervimycin complex produced by Streptomyces tendae HKI 0179. The phenotypic response of Bacillus subtilis and Staphylococcus aureus toward cervimycin C indicated a chromosome segregation and septum formation defect. This effect was at first attributed to an interaction between cervimycin C and the DNA gyrase. However, omics data of cervimycin treated versus untreated S. aureus cells indicated a different mode of action, because the stress response did not include the SOS response but resembled the response toward antibiotics that induce mistranslation or premature chain termination and cause protein stress. In summary, these results point toward a possibly novel mechanism that generates protein stress in the cells and subsequently leads to defects in cell and chromosome segregation.
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Affiliation(s)
- Alina Hoffmann
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
| | - Ursula Steffens
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
| | - Boris Maček
- University of Tübingen, Proteome Center Tübingen, Tübingen, Germany
| | | | - Kay Nieselt
- University of Tübingen, Interfaculty Institute for Bioinformatics and Medical Informatics, Tübingen, Germany
| | - Theresa Anisja Harbig
- University of Tübingen, Interfaculty Institute for Bioinformatics and Medical Informatics, Tübingen, Germany
| | - Kirstin Scherlach
- Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
| | - Christian Hertweck
- Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
- Friedrich Schiller University Jena, Institute of Microbiology, Faculty of Biological Sciences, Jena, Germany
| | - Hans-Georg Sahl
- University of Bonn, Institute for Pharmaceutical Microbiology, Bonn, Germany
| | - Gabriele Bierbaum
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
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Crozier D, Gray JM, Maltas JA, Bonomo RA, Burke ZDC, Card KJ, Scott JG. The evolution of diverse antimicrobial responses in vancomycin-intermediate Staphylococcus aureus and its therapeutic implications. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.30.569373. [PMID: 38077036 PMCID: PMC10705500 DOI: 10.1101/2023.11.30.569373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Staphylococcus aureus causes endocarditis, osteomyelitis, and bacteremia. Clinicians often prescribe vancomycin as an empiric therapy to account for methicillin-resistant S. aureus (MRSA) and narrow treatment based on culture susceptibility results. However, these results reflect a single time point before empiric treatment and represent a limited subset of the total bacterial population within the patient. Thus, while they may indicate that the infection is susceptible to a particular drug, this recommendation may no longer be accurate during therapy. Here, we addressed how antibiotic susceptibility changes over time by accounting for evolution. We evolved 18 methicillin-susceptible S. aureus (MSSA) populations under increasing vancomycin concentrations until they reached intermediate resistance levels. Sequencing revealed parallel mutations that affect cell membrane stress response and cell-wall biosynthesis. The populations exhibited repeated cross-resistance to daptomycin and varied responses to meropenem, gentamicin, and nafcillin. We accounted for this variability by deriving likelihood estimates that express a population's probability of exhibiting a drug response following vancomycin treatment. Our results suggest antistaphylococcal penicillins are preferable first-line treatments for MSSA infections but also highlight the inherent uncertainty that evolution poses to effective therapies. Infections may take varied evolutionary paths; therefore, considering evolution as a probabilistic process should inform our therapeutic choices.
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Kim YH, Park J, Chung HS. Genetic characterization of tetracycline-resistant Staphylococcus aureus with reduced vancomycin susceptibility using whole-genome sequencing. Arch Microbiol 2023; 206:24. [PMID: 38103051 DOI: 10.1007/s00203-023-03760-0] [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: 07/21/2023] [Revised: 11/09/2023] [Accepted: 11/19/2023] [Indexed: 12/17/2023]
Abstract
This study aimed to analyze the genetic characteristics of Staphylococcus aureus with reduced vancomycin susceptibility (RVS-SA). Whole-genome sequencing was performed on 27 RVS-SA clinical isolates, and comparative genomic analysis was performed using S. aureus reference strains. Pan-genome orthologous groups (POGs) were identified that were present in RVS-SA but absent in the reference strains, but further analysis showed that the presence of these POGs was influenced by tetracycline resistance rather than vancomycin resistance. Therefore, we restricted our analysis to tetracycline-resistant (tetR) RVS-SA and tetR vancomycin-susceptible S. aureus (VSSA). Phylogenomic analysis showed them to be closely related, and further analysis revealed the presence of an uncharacterized protein SAB0394 and the absence of lytA in tetR RVS-SA, which are involved in cell wall thickening. In summary, using whole-genome sequencing we identified gain or loss of genes in tetR RVS-SA strains. These findings provide insights into the investigation of mechanisms associated with reduced vancomycin susceptibility and have the potential to contribute to the development of molecular biomarkers for the rapid and efficient detection of RVS-SA.
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Affiliation(s)
- Yu-Hee Kim
- Advanced Biomedical Research Institute, Ewha Womans University Seoul Hospital, Seoul, Korea
- Ewha Education and Research Center for Infection, Ewha Womans University Medical Center, Seoul, Korea
| | - Junghun Park
- Ewha Education and Research Center for Infection, Ewha Womans University Medical Center, Seoul, Korea
| | - Hae-Sun Chung
- Ewha Education and Research Center for Infection, Ewha Womans University Medical Center, Seoul, Korea.
- Department of Laboratory Medicine, Ewha Womans University College of Medicine, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Republic of Korea.
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Li M, Liu Y, Gong Y, Yan X, Wang L, Zheng W, Ai H, Zhao Y. Recent advances in nanoantibiotics against multidrug-resistant bacteria. NANOSCALE ADVANCES 2023; 5:6278-6317. [PMID: 38024316 PMCID: PMC10662204 DOI: 10.1039/d3na00530e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 10/05/2023] [Indexed: 12/01/2023]
Abstract
Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.
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Affiliation(s)
- Mulan Li
- Cancer Research Center, Jiangxi University of Chinese Medicine No. 1688 Meiling Avenue, Xinjian District Nanchang Jiangxi 330004 P. R. China
| | - Ying Liu
- Key Laboratory of Follicular Development and Reproductive Health in Liaoning Province, Third Affiliated Hospital of Jinzhou Medical University No. 2, Section 5, Heping Road Jin Zhou Liaoning 121000 P. R. China
| | - Youhuan Gong
- Cancer Research Center, Jiangxi University of Chinese Medicine No. 1688 Meiling Avenue, Xinjian District Nanchang Jiangxi 330004 P. R. China
| | - Xiaojie Yan
- Cancer Research Center, Jiangxi University of Chinese Medicine No. 1688 Meiling Avenue, Xinjian District Nanchang Jiangxi 330004 P. R. China
| | - Le Wang
- Cancer Research Center, Jiangxi University of Chinese Medicine No. 1688 Meiling Avenue, Xinjian District Nanchang Jiangxi 330004 P. R. China
| | - Wenfu Zheng
- CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology No. 11 Zhongguancun Beiyitiao, Haidian District Beijing 100190 P. R. China
- The University of Chinese Academy of Sciences 19A Yuquan Road, Shijingshan District Beijing 100049 P. R. China
- Cannano Tefei Technology, Co. LTD Room 1013, Building D, No. 136 Kaiyuan Avenue, Huangpu District Guangzhou Guangdong Province 510535 P. R. China
| | - Hao Ai
- Key Laboratory of Follicular Development and Reproductive Health in Liaoning Province, Third Affiliated Hospital of Jinzhou Medical University No. 2, Section 5, Heping Road Jin Zhou Liaoning 121000 P. R. China
| | - Yuliang Zhao
- CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology No. 11 Zhongguancun Beiyitiao, Haidian District Beijing 100190 P. R. China
- The University of Chinese Academy of Sciences 19A Yuquan Road, Shijingshan District Beijing 100049 P. R. China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences 19B Yuquan Road, Shijingshan District Beijing 100049 P. R. China
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Cervimycin-Resistant Staphylococcus aureus Strains Display Vancomycin-Intermediate Resistant Phenotypes. Microbiol Spectr 2022; 10:e0256722. [PMID: 36173303 PMCID: PMC9603734 DOI: 10.1128/spectrum.02567-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Resistance to antibiotics is an increasing problem and necessitates novel antibacterial therapies. The polyketide antibiotics cervimycin A to D are natural products of Streptomyces tendae HKI 0179 with promising activity against multidrug-resistant staphylococci and vancomycin-resistant enterococci. To initiate mode of action studies, we selected cervimycin C- and D-resistant (CmR) Staphylococcus aureus strains. Genome sequencing of CmR mutants revealed amino acid exchanges in the essential histidine kinase WalK, the Clp protease proteolytic subunit ClpP or the Clp ATPase ClpC, and the heat shock protein DnaK. Interestingly, all characterized CmR mutants harbored a combination of mutations in walK and clpP or clpC. In vitro and in vivo analyses showed that the mutations in the Clp proteins abolished ClpP or ClpC activity, and the deletion of clpP rendered S. aureus but not all Bacillus subtilis strains cervimycin-resistant. The essential gene walK was the second mutational hotspot in the CmR S. aureus strains, which decreased WalK activity in vitro and generated a vancomycin-intermediate resistant phenotype, with a thickened cell wall, a lower growth rate, and reduced cell lysis. Transcriptomic and proteomic analyses revealed massive alterations in the CmR strains compared to the parent strain S. aureus SG511, with major shifts in the heat shock regulon, the metal ion homeostasis, and the carbohydrate metabolism. Taken together, mutations in the heat shock genes clpP, clpC, and dnaK, and the walK kinase gene in CmR mutants induced a vancomycin-intermediate resistant phenotype in S. aureus, suggesting cell wall metabolism or the Clp protease system as primary target of cervimycin. IMPORTANCE Staphylococcus aureus is a frequent cause of infections in both the community and hospital setting. Resistance development of S. aureus to various antibiotics is a severe problem for the treatment of this pathogen worldwide. New powerful antimicrobial agents against Gram-positives are needed, since antibiotics like vancomycin fail to cure vancomycin-intermediate resistant S. aureus (VISA) and vancomycin-resistant enterococci (VRE) infections. One candidate substance with promising activity against these organisms is cervimycin, which is an antibiotic complex with a yet unknown mode of action. In our study, we provide first insights into the mode of action of cervimycins. By characterizing cervimycin-resistant S. aureus strains, we revealed the Clp system and the essential kinase WalK as mutational hotspots for cervimycin resistance in S. aureus. It further emerged that cervimycin-resistant S. aureus strains show a VISA phenotype, indicating a role of cervimycin in perturbing the bacterial cell envelope.
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Molecular Mechanisms of Drug Resistance in Staphylococcus aureus. Int J Mol Sci 2022; 23:ijms23158088. [PMID: 35897667 PMCID: PMC9332259 DOI: 10.3390/ijms23158088] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 12/03/2022] Open
Abstract
This paper discusses the mechanisms of S. aureus drug resistance including: (1) introduction. (2) resistance to beta-lactam antibiotics, with particular emphasis on the mec genes found in the Staphylococcaceae family, the structure and occurrence of SCCmec cassettes, as well as differences in the presence of some virulence genes and its expression in major epidemiological types and clones of HA-MRSA, CA-MRSA, and LA-MRSA strains. Other mechanisms of resistance to beta-lactam antibiotics will also be discussed, such as mutations in the gdpP gene, BORSA or MODSA phenotypes, as well as resistance to ceftobiprole and ceftaroline. (3) Resistance to glycopeptides (VRSA, VISA, hVISA strains, vancomycin tolerance). (4) Resistance to oxazolidinones (mutational and enzymatic resistance to linezolid). (5) Resistance to MLS-B (macrolides, lincosamides, ketolides, and streptogramin B). (6) Aminoglycosides and spectinomicin, including resistance genes, their regulation and localization (plasmids, transposons, class I integrons, SCCmec), and types and spectrum of enzymes that inactivate aminoglycosides. (7). Fluoroquinolones (8) Tetracyclines, including the mechanisms of active protection of the drug target site and active efflux of the drug from the bacterial cell. (9) Mupirocin. (10) Fusidic acid. (11) Daptomycin. (12) Resistance to other antibiotics and chemioterapeutics (e.g., streptogramins A, quinupristin/dalfopristin, chloramphenicol, rifampicin, fosfomycin, trimethoprim) (13) Molecular epidemiology of MRSA.
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Bian X, Qu X, Zhang J, Nang SC, Bergen PJ, Tony Zhou Q, Chan HK, Feng M, Li J. Pharmacokinetics and pharmacodynamics of peptide antibiotics. Adv Drug Deliv Rev 2022; 183:114171. [PMID: 35189264 PMCID: PMC10019944 DOI: 10.1016/j.addr.2022.114171] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/23/2022] [Accepted: 02/16/2022] [Indexed: 01/05/2023]
Abstract
Antimicrobial resistance is a major global health challenge. As few new efficacious antibiotics will become available in the near future, peptide antibiotics continue to be major therapeutic options for treating infections caused by multidrug-resistant pathogens. Rational use of antibiotics requires optimisation of the pharmacokinetics and pharmacodynamics for the treatment of different types of infections. Toxicodynamics must also be considered to improve the safety of antibiotic use and, where appropriate, to guide therapeutic drug monitoring. This review focuses on the pharmacokinetics/pharmacodynamics/toxicodynamics of peptide antibiotics against multidrug-resistant Gram-negative and Gram-positive pathogens. Optimising antibiotic exposure at the infection site is essential for improving their efficacy and minimising emergence of resistance.
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Affiliation(s)
- Xingchen Bian
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China; Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai, China; National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China; School of Pharmacy, Fudan University, Shanghai, China
| | - Xingyi Qu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China; Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai, China; National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China; School of Pharmacy, Fudan University, Shanghai, China; Phase I Unit, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jing Zhang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China; Key Laboratory of Clinical Pharmacology of Antibiotics, Shanghai, China; National Health Commission & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China; Phase I Unit, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Sue C Nang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Australia
| | - Phillip J Bergen
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Australia
| | - Qi Tony Zhou
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, IN, USA
| | - Hak-Kim Chan
- Advanced Drug Delivery Group, School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Meiqing Feng
- School of Pharmacy, Fudan University, Shanghai, China
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Australia.
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Tocchetti A, Iorio M, Hamid Z, Armirotti A, Reggiani A, Donadio S. Understanding the Mechanism of Action of NAI-112, a Lanthipeptide with Potent Antinociceptive Activity. Molecules 2021; 26:molecules26226764. [PMID: 34833857 PMCID: PMC8624038 DOI: 10.3390/molecules26226764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/29/2021] [Accepted: 11/04/2021] [Indexed: 11/16/2022] Open
Abstract
NAI-112, a glycosylated, labionine-containing lanthipeptide with weak antibacterial activity, has demonstrated analgesic activity in relevant mouse models of nociceptive and neuropathic pain. However, the mechanism(s) through which NAI-112 exerts its analgesic and antibacterial activities is not known. In this study, we analyzed changes in the spinal cord lipidome resulting from treatment with NAI-112 of naive and in-pain mice. Notably, NAI-112 led to an increase in phosphatidic acid levels in both no-pain and pain models and to a decrease in lysophosphatidic acid levels in the pain model only. We also showed that NAI-112 can form complexes with dipalmitoyl-phosphatidic acid and that Staphylococcus aureus can become resistant to NAI-112 through serial passages at sub-inhibitory concentrations of the compound. The resulting resistant mutants were phenotypically and genotypically related to vancomycin-insensitive S. aureus strains, suggesting that NAI-112 binds to the peptidoglycan intermediate lipid II. Altogether, our results suggest that NAI-112 binds to phosphate-containing lipids and blocks pain sensation by decreasing levels of lysophosphatidic acid in the TRPV1 pathway.
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Affiliation(s)
| | - Marianna Iorio
- Naicons Srl, Viale Ortles 22/4, 20139 Milan, Italy; (A.T.); (S.D.)
- Correspondence:
| | - Zeeshan Hamid
- D3 Validation, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy; (Z.H.); (A.R.)
| | - Andrea Armirotti
- Analytical Chemistry Lab, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy;
| | - Angelo Reggiani
- D3 Validation, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy; (Z.H.); (A.R.)
| | - Stefano Donadio
- Naicons Srl, Viale Ortles 22/4, 20139 Milan, Italy; (A.T.); (S.D.)
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Inferring multilayer interactome networks shaping phenotypic plasticity and evolution. Nat Commun 2021; 12:5304. [PMID: 34489412 PMCID: PMC8421358 DOI: 10.1038/s41467-021-25086-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 07/12/2021] [Indexed: 02/07/2023] Open
Abstract
Phenotypic plasticity represents a capacity by which the organism changes its phenotypes in response to environmental stimuli. Despite its pivotal role in adaptive evolution, how phenotypic plasticity is genetically controlled remains elusive. Here, we develop a unified framework for coalescing all single nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS) into a quantitative graph. This framework integrates functional genetic mapping, evolutionary game theory, and predator-prey theory to decompose the net genetic effect of each SNP into its independent and dependent components. The independent effect arises from the intrinsic capacity of a SNP, only expressed when it is in isolation, whereas the dependent effect results from the extrinsic influence of other SNPs. The dependent effect is conceptually beyond the traditional definition of epistasis by not only characterizing the strength of epistasis but also capturing the bi-causality of epistasis and the sign of the causality. We implement functional clustering and variable selection to infer multilayer, sparse, and multiplex interactome networks from any dimension of genetic data. We design and conduct two GWAS experiments using Staphylococcus aureus, aimed to test the genetic mechanisms underlying the phenotypic plasticity of this species to vancomycin exposure and Escherichia coli coexistence. We reconstruct the two most comprehensive genetic networks for abiotic and biotic phenotypic plasticity. Pathway analysis shows that SNP-SNP epistasis for phenotypic plasticity can be annotated to protein-protein interactions through coding genes. Our model can unveil the regulatory mechanisms of significant loci and excavate missing heritability from some insignificant loci. Our multilayer genetic networks provide a systems tool for dissecting environment-induced evolution.
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Baseri N, Najar-Peerayeh S, Bakhshi B. Investigating the effect of an identified mutation within a critical site of PAS domain of WalK protein in a vancomycin-intermediate resistant Staphylococcus aureus by computational approaches. BMC Microbiol 2021; 21:240. [PMID: 34474665 PMCID: PMC8414773 DOI: 10.1186/s12866-021-02298-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/23/2021] [Indexed: 11/15/2022] Open
Abstract
Background Vancomycin-intermediate resistant Staphylococcus aureus (VISA) is becoming a common cause of nosocomial infections worldwide. VISA isolates are developed by unclear molecular mechanisms via mutations in several genes, including walKR. Although studies have verified some of these mutations, there are a few studies that pay attention to the importance of molecular modelling of mutations. Method For genomic and transcriptomic comparisons in a laboratory-derived VISA strain and its parental strain, Sanger sequencing and reverse transcriptase quantitative PCR (RT-qPCR) methods were used, respectively. After structural protein mapping of the detected mutation, mutation effects were analyzed using molecular computational approaches and crystal structures of related proteins. Results A mutation WalK-H364R was occurred in a functional zinc ion coordinating residue within the PAS domain in the VISA strain. WalK-H364R was predicted to destabilize protein and decrease WalK interactions with proteins and nucleic acids. The RT-qPCR method showed downregulation of walKR, WalKR-regulated autolysins, and agr locus. Conclusion Overall, WalK-H364R mutation within a critical metal-coordinating site was presumably related to the VISA development. We assume that the WalK-H364R mutation resulted in deleterious effects on protein, which was verified by walKR gene expression changes.. Therefore, molecular modelling provides detailed insight into the molecular mechanism of VISA development, in particular, where allelic replacement experiments are not readily available. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02298-9.
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Affiliation(s)
- Neda Baseri
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Shahin Najar-Peerayeh
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Bita Bakhshi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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Dahdouh E, Díaz-Pollán B, Falces-Romero I, Mingorance J, Gómez-Gil R. Characterization of an osteomyelitis case caused by dalbavancin, ceftaroline, and vancomycin non-susceptible methicillin-resistant Staphylococcus aureus. Eur J Clin Microbiol Infect Dis 2021; 40:2029-2032. [PMID: 33686556 DOI: 10.1007/s10096-021-04219-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 03/04/2021] [Indexed: 10/22/2022]
Abstract
We report a case of osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) that is also non-susceptible to vancomycin, dalbavancin, ceftaroline, and ceftobiprole, in the absence of exposure to the latter three antibiotics. It was isolated from a patient with a 26-year history of cranial surgeries and episodes of osteomyelitis. Whole-genome sequencing was performed. It was found to belong to ST247 and the mecA gene was detected within the SSCmec type I (1B) gene cassette that lacked the E447K mutation known to produce resistance to ceftobiprole and ceftaroline. However, mutations in other genes related to resistance to these antibiotics were found.
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Affiliation(s)
- Elias Dahdouh
- Clinical Microbiology and Parasitology Department, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain.
| | - Beatriz Díaz-Pollán
- Clinical Microbiology and Infectious Diseases Unit, Hospital Universitario La Paz, Madrid, Spain
| | - Iker Falces-Romero
- Clinical Microbiology and Parasitology Department, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain
| | - Jesús Mingorance
- Clinical Microbiology and Parasitology Department, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain
| | - Rosa Gómez-Gil
- Clinical Microbiology and Parasitology Department, Hospital Universitario La Paz, IdiPAZ, Madrid, Spain
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