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Mapar M, Rydzak T, Hommes JW, Surewaard BGJ, Lewis IA. Diverse molecular mechanisms underpinning Staphylococcus aureus small colony variants. Trends Microbiol 2024:S0966-842X(24)00251-8. [PMID: 39393939 DOI: 10.1016/j.tim.2024.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 09/19/2024] [Accepted: 09/20/2024] [Indexed: 10/13/2024]
Abstract
Small colony variants (SCVs) of Staphylococcus aureus are a relatively rare but clinically significant growth morphotype. Infections with SCVs are frequently difficult to treat, inherently antibiotic-resistant, and can lead to persistent infections. Despite a long history of research, the molecular underpinnings of this morphotype and their impact on the clinical trajectory of infections remain unclear. However, a growing body of literature indicates that SCVs are caused by a diverse range of molecular factors. These recent findings suggest that SCVs should be thought of as an ensemble collection of loosely related phenotypes, and not as a single phenomenon. This review describes the diverse mechanisms currently known to contribute to SCVs and proposes an ensemble model for conceptualizing this morphotype.
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Affiliation(s)
- Maryam Mapar
- Alberta Centre for Advanced Diagnostics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Thomas Rydzak
- Alberta Centre for Advanced Diagnostics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Josefien W Hommes
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Bas G J Surewaard
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ian A Lewis
- Alberta Centre for Advanced Diagnostics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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Liu G, Gui Y, Shi W, Yang H, Feng S, Liang S, Zhou C, Zhou Q, Li H, Li G, Si H, Ou C. Therapeutic efficacy of compound organic acids administration on methicillin-resistant Staphylococcus aureus-induced arthritis in broilers. Poult Sci 2024; 103:104219. [PMID: 39278110 PMCID: PMC11419824 DOI: 10.1016/j.psj.2024.104219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 08/03/2024] [Accepted: 08/09/2024] [Indexed: 09/17/2024] Open
Abstract
Avian arthritis is a common disease in the poultry industry, and the etiology is complex. Bacterial arthritis is usually caused by Staphylococcus aureus (S. aureus) infection. This study explored the minimum inhibitory concentration (MIC) of different organic acids against S. aureus MRSA85 and found that vanillic acid, suberic acid, itaconic acid, salicylic acid, and other organic acids had significant inhibitory effects on this strain, especially cinnamic acid, which exhibited the best inhibitory effect. The Fractional Inhibitory Concentration Index (FICI) test further revealed the synergistic effect among some compound organic acids, which can significantly enhance the antibacterial efficiency against MRSA85 while reducing the risk of bacterial resistance. Under the low concentrations (1/2 or 1/4 MIC) conditions, the MIC of the compound organic acids against S. aureus remains unchanged, and it can even enhance the sensitivity of antibiotic-resistant S. aureus to Oxacillin. Furthermore, the compound organic acids could effectively promote the recovery of S. aureus-induced arthritis in broiler models, reduce inflammatory responses, and lower down bacterial loads and inflammatory cytokine levels in joints, which indicated that the effects of the Compound 2 is comparable to that of the trimethoprim-sulfamethoxazole group. These results support the potential and application value of organic acids and their compounds, including Compound 1 to 3, as novel antibacterial agents in the treatment of S. aureus infections.
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Affiliation(s)
- Gengsong Liu
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Yanyao Gui
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Wen Shi
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Hongchun Yang
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Shufeng Feng
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Si Liang
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Congcong Zhou
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Qiaoyan Zhou
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Haizhu Li
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Gonghe Li
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Hongbin Si
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China; Guangxi Zhuang Autonomous Region Engineering Research Center of Veterinary Biologics, Nanning, 530004, China; Guangxi Key Laboratory of Animal Reproduction, Breeding and Disease Control, Nanning, 530004, China
| | - Changbo Ou
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China; Guangxi Zhuang Autonomous Region Engineering Research Center of Veterinary Biologics, Nanning, 530004, China; Guangxi Key Laboratory of Animal Reproduction, Breeding and Disease Control, Nanning, 530004, China.
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Obermueller M, Traby L, Weiss-Tessbach M, Kriz R, Spettel K, Schneider L, Hohl L, Burgmann H, Kussmann M. Staphylococcus aureus small colony variants: A potentially underestimated microbiological challenge in peritoneal dialysis. Int J Antimicrob Agents 2024; 63:107135. [PMID: 38458357 DOI: 10.1016/j.ijantimicag.2024.107135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/03/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024]
Abstract
INTRODUCTION Peritonitis remains the major infectious complication in the setting of peritoneal dialysis (PD). Despite known only moderate pathogenicity, the most frequently detected pathogens in PD-related peritonitis are surprisingly coagulase-negative staphylococci. However, this could be explained, at least in part, by Staphylococcus aureus small colony variants (SCVs) induced by PD fluids (PDFs) and misidentified by routinely used microbiological methods. MATERIAL AND METHODS Bacteria were exposed to commonly used PDFs in various regimens designed to simulate daily use as closely as possible. Wild-type isolates and SCVs were subsequently used to determine minimum inhibitory concentrations (MICs), in vitro biofilm formation capacities, and auxotrophies. Underlying genetic alterations were investigated using whole-genome sequencing, and various microbial identification methods were tested to determine their performance for wild-types and SCVs. RESULTS Stable SCVs could be isolated most successfully after exposure to glucose-containing PDFs alone. The reading of MICs was significantly affected by the reduced growth of SCVs, resulting in lower MIC values in 44% of all tests. Nonsynonymous mutations were found in all but one SCV, while only two isolates showed typical auxotrophic responses. While MALDI-TOF, PCR and Pastorex Staph-Plus correctly identified all S. aureus SCVs, API-Staph and VITEK-2 yielded identification rates of only 40% and 10%, respectively. CONCLUSIONS Overall, the present study has shown that commercially available PDFs induce S. aureus SCVs in vitro, which are difficult to identify and test for antimicrobial susceptibility and can potentially lead to recurrent or persistent infections. Thus, they represent a potentially underappreciated challenge not only for microbiologists, but also for clinicians.
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Affiliation(s)
- Markus Obermueller
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Ludwig Traby
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Matthias Weiss-Tessbach
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria; Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria
| | - Richard Kriz
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Kathrin Spettel
- Department of Laboratory Medicine, Division of Clinical Microbiology, Medical University of Vienna, Vienna, Austria
| | - Lisa Schneider
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Lena Hohl
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Heinz Burgmann
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria
| | - Manuel Kussmann
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University Vienna, Vienna, Austria.
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Bogut A, Koper P, Marczak M, Całka P. The first genomic characterization of a stable, hemin-dependent small colony variant strain of Staphylococcus epidermidis isolated from a prosthetic-joint infection. Front Microbiol 2023; 14:1289844. [PMID: 37928677 PMCID: PMC10620731 DOI: 10.3389/fmicb.2023.1289844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023] Open
Abstract
Phenotype switching from a wild type (WT) to a slow-growing subpopulation, referred to as small colony variants (SCVs), supports an infectious lifestyle of Staphylococcus epidermidis, the leading cause of medical device-related infections. Specific mechanisms underlying formation of SCVs and involved in the shaping of their pathogenic potential are of particular interest for stable strains as they have been only rarely cultured from clinical specimens. As the SCV phenotype stability implies the existence of genetic changes, the whole genome sequence of a stable, hemin-dependent S. epidermidis SCV strain (named 49SCV) involved in a late prosthetic joint infection was analyzed. The strain was isolated in a monoculture without a corresponding WT clone, therefore, its genome was compared against five reference S. epidermidis strains (ATCC12228, ATCC14990, NBRC113846, O47, and RP62A), both at the level of the genome structure and coding sequences. According to the Multilocus Sequence Typing analysis, the 49SCV strain represented the sequence type 2 (ST2) regarded as the most prominent infection-causing lineage with a worldwide dissemination. Genomic features unique to 49SCV included the absence of the Staphylococcal Cassette Chromosome (SCC), ~12 kb deletion with the loss of genes involved in the arginine deiminase pathway, and frameshift-generating mutations within the poly(A) and poly(T) homopolymeric tracts. Indels were identified in loci associated with adherence, metabolism, stress response, virulence, and cell wall synthesis. Of note, deletion in the poly(A) of the hemA gene has been considered a possible trigger factor for the phenotype transition and hemin auxotrophy in the strain. To our knowledge, the study represents the first genomic characterization of a clinical, stable and hemin-dependent S. epidermidis SCV strain. We propose that previously unreported indels in the homopolymeric tracts can constitute a background of the SCV phenotype due to a resulting truncation of the corresponding proteins and their possible biological dysfunction. Streamline of genetic content evidenced by the loss of the SCC and a large genomic deletion can represent a possible strategy associated both with the SCV phenotype and its adaptation to chronicity.
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Affiliation(s)
- Agnieszka Bogut
- Chair and Department of Medical Microbiology, Medical University of Lublin, Lublin, Poland
| | - Piotr Koper
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Małgorzata Marczak
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Paulina Całka
- Chair and Department of Forensic Medicine, Medical University of Lublin, Lublin, Poland
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Becker K. Detection, Identification and Diagnostic Characterization of the Staphylococcal Small Colony-Variant (SCV) Phenotype. Antibiotics (Basel) 2023; 12:1446. [PMID: 37760742 PMCID: PMC10525764 DOI: 10.3390/antibiotics12091446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
While modern molecular methods have decisively accelerated and improved microbiological diagnostics, phenotypic variants still pose a challenge for their detection, identification and characterization. This particularly applies if they are unstable and hard to detect, which is the case for the small-colony-variant (SCV) phenotype formed by staphylococci. On solid agar media, staphylococcal SCVs are characterized by tiny colonies with deviant colony morphology. Their reduced growth rate and fundamental metabolic changes are the result of their adaptation to an intracellular lifestyle, regularly leading to specific auxotrophies, such as for menadione, hemin or thymidine. These alterations make SCVs difficult to recognize and render physiological, biochemical and other growth-based methods such as antimicrobial susceptibility testing unreliable or unusable. Therefore, diagnostic procedures require prolonged incubation times and, if possible, confirmation by molecular methods. A special approach is needed for auxotrophy testing. However, standardized protocols for SCV diagnostics are missing. If available, SCVs and their putative parental isolates should be genotyped to determine clonality. Since their detection has significant implications for the treatment of the infection, which is usually chronic and relapsing, SCV findings should be specifically reported, commented on, and managed in close collaboration with the microbiological laboratory and the involved clinicians.
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Affiliation(s)
- Karsten Becker
- Friedrich Loeffler-Institute of Medical Microbiology, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße 1, 17489 Greifswald, Germany
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Gostev V, Kalinogorskaya O, Sopova J, Sulian O, Chulkova P, Velizhanina M, Tsvetkova I, Ageevets I, Ageevets V, Sidorenko S. Adaptive Laboratory Evolution of Staphylococcus aureus Resistance to Vancomycin and Daptomycin: Mutation Patterns and Cross-Resistance. Antibiotics (Basel) 2023; 12:antibiotics12050928. [PMID: 37237831 DOI: 10.3390/antibiotics12050928] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Vancomycin and daptomycin are first-line drugs for the treatment of complicated methicillin-resistant Staphylococcus aureus (MRSA) infections, including bacteremia. However, their effectiveness is limited not only by their resistance to each antibiotic but also by their associated resistance to both drugs. It is unknown whether novel lipoglycopeptides can overcome this associated resistance. Resistant derivatives from five S. aureus strains were obtained during adaptive laboratory evolution with vancomycin and daptomycin. Both parental and derivative strains were subjected to susceptibility testing, population analysis profiles, measurements of growth rate and autolytic activity, and whole-genome sequencing. Regardless of whether vancomycin or daptomycin was selected, most of the derivatives were characterized by a reduced susceptibility to daptomycin, vancomycin, telavancin, dalbavancin, and oritavancin. Resistance to induced autolysis was observed in all derivatives. Daptomycin resistance was associated with a significant reduction in growth rate. Resistance to vancomycin was mainly associated with mutations in the genes responsible for cell wall biosynthesis, and resistance to daptomycin was associated with mutations in the genes responsible for phospholipid biosynthesis and glycerol metabolism. However, mutations in walK and mprF were detected in derivatives selected for both antibiotics.
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Affiliation(s)
- Vladimir Gostev
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
- Department of Medical Microbiology, North-Western State Medical University named after I.I. Mechnikov, 195067 Saint Petersburg, Russia
| | - Olga Kalinogorskaya
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Julia Sopova
- Center of Transgenesis and Genome Editing, Saint Petersburg State University, 199034 Saint Petersburg, Russia
- Saint Petersburg Branch of Vavilov Institute of General Genetics, Russian Academy of Sciences, 198504 Saint Petersburg, Russia
| | - Ofelia Sulian
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Polina Chulkova
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Maria Velizhanina
- Center of Transgenesis and Genome Editing, Saint Petersburg State University, 199034 Saint Petersburg, Russia
- Laboratory of Signal Regulation, All-Russia Research Institute for Agricultural Microbiology, Pushkin, 196608 Saint Petersburg, Russia
| | - Irina Tsvetkova
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Irina Ageevets
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Vladimir Ageevets
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
| | - Sergey Sidorenko
- Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical Microbiology and Molecular Epidemiology, 197022 Saint Petersburg, Russia
- Department of Medical Microbiology, North-Western State Medical University named after I.I. Mechnikov, 195067 Saint Petersburg, Russia
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Staphylococcus aureus Genomic Analysis and Outcomes in Patients with Bone and Joint Infections: A Systematic Review. Int J Mol Sci 2023; 24:ijms24043234. [PMID: 36834650 PMCID: PMC9967247 DOI: 10.3390/ijms24043234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023] Open
Abstract
Many studies have been published assessing the association between the presence of S. aureus genes and outcomes in patients with bone and joint infections (BJI), but it is not known if they have had similar findings. A systematic literature review was performed. All available data on studies in Pubmed between January 2000 to October 2022 reporting the genetic characteristics of S. aureus and the outcomes of BJIs were analyzed. BJI included prosthetic joint infection (PJI), osteomyelitis (OM), diabetic foot infection (DFI), and septic arthritis. Because of the heterogeneity of studies and outcomes, no meta-analysis was performed. With the search strategy, 34 articles were included: 15 articles on children and 19 articles on adults. In children, most BJI studied were OM (n = 13) and septic arthritis (n = 9). Panton Valentine leucocidin (PVL) genes were associated with higher biological inflammatory markers at presentation (n = 4 studies), more febrile days (n = 3), and more complicated/severe infection (n = 4). Other genes were reported anecdotally associated with poor outcomes. In adults, six studies reported outcomes in patients with PJI, 2 with DFI, 3 with OM, and 3 with various BJI. Several genes were associated with a variety of poor outcomes in adults, but studies found contradictory results. Whereas PVL genes were associated with poor outcomes in children, no specific genes were reported similarly in adults. Additional studies with homogenous BJI and larger sample sizes are needed.
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Zhou S, Rao Y, Li J, Huang Q, Rao X. Staphylococcus aureus small-colony variants: Formation, infection, and treatment. Microbiol Res 2022; 260:127040. [DOI: 10.1016/j.micres.2022.127040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 10/18/2022]
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Novel Daptomycin Tolerance and Resistance Mutations in Methicillin-Resistant Staphylococcus aureus from Adaptive Laboratory Evolution. mSphere 2021; 6:e0069221. [PMID: 34585959 PMCID: PMC8550074 DOI: 10.1128/msphere.00692-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
It has been shown recently in a number of in vitro laboratory evolution experiments that under repetitive antibiotic exposure, bacterial populations can adapt quickly to the treatment condition by becoming tolerant and/or resistant to the drug. The repeated killing and regrowth cycles hasten the selection for tolerant/resistant mutants with survival advantages. Due to the random nature of mutagenesis and the large target size of tolerance mutations, this dynamic evolutionary process appears to be highly unpredictable, generating distinct mutants even under identical, well-controlled laboratory conditions. Here, we utilized an adaptive laboratory evolution (ALE) experiment to hunt for novel tolerance and resistance mutations by subjecting multiple lineages of methicillin-resistant Staphylococcus aureus (MRSA) to repetitive daptomycin treatment. By sequencing multiple isolates along the course of evolution, we obtained three tolerant mutants that have different tolerance levels and identified novel daptomycin resistance mutations in the mprF gene. In addition, we found that tolerance/resistance development is more rapid if the population is treated in the exponential phase than if it is treated in the stationary phase, which is likely attributable to the more effective killing of growing cells by the antibiotic. Through competition assays, we found that whether or not the resistant mutants can take over the population heavily depends on the relative survival advantages conferred by the tolerance and resistance mutations. This study reports novel daptomycin resistance and tolerance mutations and offers new insights into the dynamics of the development of tolerance and resistance in bacterial populations under antibiotic exposure. IMPORTANCE Although the phenotype of increased tolerance and/or resistance was commonly observed in evolved populations from typical adaptive laboratory evolution (ALE) experiments, a wide variety of mutations that underlie those phenotypes have been discovered. Therefore, performing ALE experiments in multiple populations in parallel would serve the purpose of mining for different tolerant/resistant mutants and would be useful to explore the diverse population dynamics of evolution. In this study, we performed in vitro evolution in a clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) pathogen, using a lethal concentration of a drug that is frequently used in the clinic, daptomycin. Using this strategy, we obtained three distinct daptomycin-tolerant mutants and identified six daptomycin resistance mutations in different locations on the mprF gene, collectively adding to our current knowledge of this important pathogen. In addition, we found out that in most cases, the daptomycin-resistant mutant outcompetes other susceptible and tolerant mutants and becomes established in the final population. Follow-up competition experiments offered an explanation; the resistant mutant cannot invade populations of tolerant mutants that confer higher survival advantages than itself. In summary, we demonstrated an experimental strategy to explore the landscape and dynamics of the evolution of tolerance and resistance in MRSA toward daptomycin and made observations that will guide future ALE experiments.
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Liu J, Shen Z, Tang J, Huang Q, Jian Y, Liu Y, Wang Y, Ma X, Liu Q, He L, Li M. Extracellular DNA released by glycine-auxotrophic Staphylococcus epidermidis small colony variant facilitates catheter-related infections. Commun Biol 2021; 4:904. [PMID: 34294851 PMCID: PMC8298460 DOI: 10.1038/s42003-021-02423-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/05/2021] [Indexed: 11/09/2022] Open
Abstract
Though a definitive link between small colony variants (SCVs) and implant-related staphylococcal infections has been well-established, the specific underlying mechanism remains an ill-explored field. The present study analyzes the role SCVs play in catheter infection by performing genomic and metabolic analyses, as well as analyzing biofilm formation and impacts of glycine on growth and peptidoglycan-linking rate, on a clinically typical Staphylococcus epidermidis case harboring stable SCV, normal counterpart (NC) and nonstable SCV. Our findings reveal that S. epidermidis stable SCV carries mutations involved in various metabolic processes. Metabolome analyses demonstrate that two biosynthetic pathways are apparently disturbed in SCV. One is glycine biosynthesis, which contributes to remarkable glycine shortage, and supplementation of glycine restores growth and peptidoglycan-linking rate of SCV. The other is overflow of pyruvic acid and acetyl-CoA, leading to excessive acetate. SCV demonstrates higher biofilm-forming ability due to rapid autolysis and subsequent eDNA release. Despite a remarkable decline in cell viability, SCV can facilitate in vitro biofilm formation and in vivo survival of NC when co-infected with its normal counterparts. This work illustrates an intriguing strategy utilized by a glycine-auxotrophic clinical S. epidermidis SCV isolate to facilitate biofilm-related infections, and casts a new light on the role of SCV in persistent infections.
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Affiliation(s)
- Junlan Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Zhen Shen
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Jin Tang
- Department of Laboratory Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Qian Huang
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Ying Jian
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Yao Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Yanan Wang
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Xiaowei Ma
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Qian Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Lei He
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
| | - Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China. .,Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Virulence alterations in staphylococcus aureus upon treatment with the sub-inhibitory concentrations of antibiotics. J Adv Res 2021; 31:165-175. [PMID: 34194840 PMCID: PMC8240104 DOI: 10.1016/j.jare.2021.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 12/24/2022] Open
Abstract
Background The treatment of patients with Staphylococcus aureus infections mainly relies on antistaphylococcal regimens that are established with effective antibiotics. In antibiotic therapy or while living in nature, pathogens often face the sub-inhibitory concentrations (sub-MICs) of antibiotics due to drug pharmacokinetics, diffusion barriers, waste emission, resistant organism formation, and farming application. Different categories of antibiotics at sub-MICs have diverse effects on the physiological and chemical properties of microorganisms. These effects can result in virulence alterations. However, the mechanisms underlying the actions of antibiotics at sub-MICs on S. aureus virulence are obscure. Aim of review In this review, we focus on the effects of sub-MICs of antibiotics on S. aureus virulence from the aspects of cell morphological change, virulence factor expression, bacterial adherence and invasion, staphylococcal biofilm formation, and small-colony variant (SCV) production. The possible mechanisms of antibiotic-induced S. aureus virulence alterations are also addressed. Key scientific concepts of review Five main aspects of bacterial virulence can be changed in S. aureus exposure to the sub-MIC levels of antibiotics, resulting in deformed bacterial cells to stimulate abnormal host immune responses, abnormally expressed virulence factors to alter disease development, changed bacterial adhesion and invasion abilities to affect colonization and diffusion, altered biofilm formation to potentate material-related infections, and increased SCV formation to achieve persistent infection and recurrence. These advanced findings expand our knowledge to rethink the molecular signaling roles of antibiotics beyond their actions as antimicrobial agents.
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Oliveira-Júnior JB, da Silva EM, Veras DL, Ribeiro KRC, de Freitas CF, de Lima FCG, Gutierrez SJC, Camara CA, Barbosa-Filho JM, Alves LC, Brayner FA. Antimicrobial activity and biofilm inhibition of riparins I, II and III and ultrastructural changes in multidrug-resistant bacteria of medical importance. Microb Pathog 2020; 149:104529. [PMID: 33010367 DOI: 10.1016/j.micpath.2020.104529] [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: 07/10/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 10/23/2022]
Abstract
Natural products have been used to treat various infections; however, the development of antimicrobials has made natural products in disuse. Riparin I, II and III are natural alkamide isolated from Aniba riparia (Ness) Mez (Lauraceae), that exhibit economic importance and it is used in traditional medicine, and popularly known as "louro". This study investigated the cytotoxicity, antimicrobial and antibiofilm activity, and ultrastructural changes in vitro by riparins I, II and III in Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. We analyzed the cytotoxicity by MTT assay in Vero cells and hemolytic action verified in human erythrocytes. The antimicrobial activity was determined by microdilution in broth against ATCC strains, identifying the susceptible species. Subsequently, only the MDR isolates of sensitive bacterial species were evaluated regarding its biofilm formation and ultrastructural changes. Riparin I presented low cytotoxicity and hemolytic percentage ranging from of 9.01%-12.97%. Only the riparin III that showed antimicrobial activity against MDR clinical isolates, and significant reduction in biofilm formation in S. aureus. Moreover, the riparin III promoted ultrastructural changes in bacterial cells, such as elongated cellular without bacterial septum, cells with a rugged appearance on the cell surface and cytoplasmic material extravasation. As has been noted riparin III has an inhibitory potential against biofilm formation in S. aureus, besides having antimicrobial activity and promoting ultrastructural changes in MDR clinical isolates. Thus, riparin III is an interesting alternative for further studies aiming to develop new therapeutic options.
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Affiliation(s)
- Jorge Belém Oliveira-Júnior
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil.
| | - Everton Morais da Silva
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil
| | - Dyana Leal Veras
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil
| | - Karla Raíza Cardoso Ribeiro
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil
| | - Catarina Fernandes de Freitas
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil
| | - Fernanda Cristina Gomes de Lima
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil
| | - Stanley Juan Chavez Gutierrez
- Pharmacy Course Coordination, Federal University of Piauí (Campus Universitário Ministro Petrônio Portela, SG-8 - Bairro Ininga, Teresina, PI, 64049-550, Brazil
| | - Celso Amorim Camara
- Department of Chemistry, Rural Federal University of Pernambuco (Rua Dom Manuel de Medeiros, S/n - Dois Irmãos, Recife, PE, 52171-900, Brazil
| | - José Maria Barbosa-Filho
- Laboratory of Pharmaceutical Technology, Federal University of Paraíba (Campus I - Lot. Cidade Universitária, João Pessoa, PB, 58051-900, Brazil
| | - Luiz Carlos Alves
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil; Electronic Microscopy, Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco (Av. Prof. Moraes Rego, 1235 - Cidade Universitária, Recife, PE, 50670-901, Brazil
| | - Fábio André Brayner
- Laboratory of Molecular and Cellular Biology, Department of Parasitology, Institute Aggeu Magalhães - FIOCRUZ/PE (Av. Prof. Moraes Rego, S/n - Cidade Universitária, Recife/PE, 50670-420, Brazil; Electronic Microscopy, Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco (Av. Prof. Moraes Rego, 1235 - Cidade Universitária, Recife, PE, 50670-901, Brazil
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13
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Gounani Z, Şen Karaman D, Venu AP, Cheng F, Rosenholm JM. Coculture of P. aeruginosa and S. aureus on cell derived matrix - An in vitro model of biofilms in infected wounds. J Microbiol Methods 2020; 175:105994. [PMID: 32593628 DOI: 10.1016/j.mimet.2020.105994] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/22/2023]
Abstract
Polymicrobial biofilms are major complications of various chronic infections. Therefore, in vitro biorelevant polymicrobial biofilm models are essential tools for medical studies. This study presents an in vitro model for dual species biofilm of Pseudomonas aeruginosa and Staphylococcus aureus developed on cell-derived matrices (CDMs), in order to simulate the microenvironment of in vivo biofilms. P. aeruginosa and S. aureus are two of the most frequent pathogens in polymicrobial biofilms of wound infections. Although they are commonly isolated from polymicrobial biofilms, their interaction is antagonistic; and there is severe battle between them for nutrients and space. We introduced a nutritious formulation supporting co-cultures of P. aeruginosa and S. aureus in order to study the interaction of these gram-positive and gram-negative bacterial species. Quantitative analyses demonstrated that the enrichment of tryptic soy broth (TSB) with NaCl and glucose facilitate dual-species biofilm formation of P. aeruginosa and S. aureus when it is mixed with fetal bovine serum (FBS). Furthermore, the dual species biofilm was incubated on CDMs. Characterization of the model by fluorescent and electron microscopy techniques revealed realistic features of chronic multi-species biofilms, including competitive distribution pattern of two bacterial species and small-colony variants (SCVs) morphology of S. aureus.
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Affiliation(s)
- Zahra Gounani
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Turku 20520, Finland; Physics, Faculty of Science and Engineering, Åbo Akademi University, Turku 20500, Finland.
| | - Didem Şen Karaman
- Biomedical Engineering Department, Faculty of Engineering and Architecture, İzmir Katip Çelebi University, İzmir, Turkey
| | - Arun P Venu
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku 20520, Finland
| | - Fang Cheng
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku 20520, Finland; School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou 510006, China
| | - Jessica M Rosenholm
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Turku 20520, Finland.
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14
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Tuchscherr L, Löffler B, Proctor RA. Persistence of Staphylococcus aureus: Multiple Metabolic Pathways Impact the Expression of Virulence Factors in Small-Colony Variants (SCVs). Front Microbiol 2020; 11:1028. [PMID: 32508801 PMCID: PMC7253646 DOI: 10.3389/fmicb.2020.01028] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/27/2020] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus is able to survive within host cells by switching its phenotype to the small-colony variant (SCV) phenotype. The emergence of SCVs is associated with the development of persistent infections, which may be both chronic and recurrent. This slow-growing subpopulation of S. aureus forms small colonies on solid-medium agar, is induced within host cells, presents a non-homogenous genetic background, has reduced expression of virulence factors and presents a variable phenotype (stable or unstable). While virtually all SCVs isolated from clinical specimens can revert to the parental state with rapid growth, the stable SCVs recovered in clinical specimens have been found to contain specific mutations in metabolic pathways. In contrast, other non-stable SCVs are originated from regulatory mechanisms involving global regulators (e.g., sigB, sarA, and agr) or other non-defined mutations. One major characteristic of SCVs was the observation that SCVs were recovered from five patients with infections that could persist for decades. In these five cases, the SCVs had defects in electron transport. This linked persistent infections with SCVs. The term "persistent infection" is a clinical term wherein bacteria remain in the host for prolonged periods of time, sometimes with recurrent infection, despite apparently active antibiotics. These terms were described in vitro where bacteria remain viable in liquid culture medium in the presence of antibiotics. These bacteria are called "persisters". While SCVs can be persisters in liquid culture, not all persisters are SCVs. One mechanism associated with the metabolically variant SCVs is the reduced production of virulence factors. SCVs have consistently shown reduced levels of RNAIII, a product of the accessory gene regulatory (agrBDCA) locus that controls a quorum-sensing system and regulates the expression of a large number of virulence genes. Reduced Agr acitivity is associated with enhanced survival of SCVs within host cells. In this review, we examine the impact of the SCVs with altered metabolic pathways on agr, and we draw distinctions with other types of SCVs that emerge within mammalian cells with prolonged infection.
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Affiliation(s)
- Lorena Tuchscherr
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, Jena University Hospital, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, University of Wisconsin Medical School, Madison, WI, United States
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15
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Bakshi NK, Inclan PM, Kirsch JM, Bedi A, Agresta C, Freehill MT. Current Workload Recommendations in Baseball Pitchers: A Systematic Review. Am J Sports Med 2020; 48:229-241. [PMID: 31013139 DOI: 10.1177/0363546519831010] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Several recommendations have been made regarding pitch counts and workload for baseball players of different levels, including Little League, high school, collegiate, and professional baseball. However, little consensus is found in the literature regarding the scientific basis for many of these recommendations. PURPOSE The primary purpose of this study was to summarize the evidence regarding immediate and long-term musculoskeletal responses to increasing pitching workload in baseball pitchers of all levels. A secondary purpose of this review was to evaluate the extent to which workload influences injury and/or performance in baseball pitchers. STUDY DESIGN Systematic review. METHODS We performed a systematic search in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies addressing physiologic and/or pathologic musculoskeletal changes in response to a quantifiable pitching workload. We included studies examining the effects of pitching workload on performance, injury rate, and musculoskeletal changes in Little League, high school, collegiate, and professional baseball players. RESULTS We identified 28 studies that met our inclusion and exclusion criteria: 16 studies regarding Little League and high school pitchers and 12 studies regarding collegiate and professional pitchers. The current evidence presented suggests that increased pitching workload may be associated with an increased risk of pain, injury, and arm fatigue in Little League and high school pitchers. However, little consensus was found in the literature regarding the association between pitching workload and physiologic or pathologic changes in collegiate and professional pitchers. CONCLUSION Evidence, although limited, suggests the use of pitch counts to decrease injury rates and pain in Little League and high school baseball pitchers. However, further research must be performed to determine the appropriate number of pitches (or throws) for players of different ages. This systematic review reported conflicting evidence regarding the use of pitch counts in college and professional baseball. Future high-quality research is required to determine the role, if any, of pitch counts for collegiate and professional pitchers.
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Affiliation(s)
- Neil K Bakshi
- Department of Orthopedic Surgery, University of Michigan, Ypsilanti, Michigan, USA
| | - Paul M Inclan
- Department of Orthopedic Surgery, Washington University in St Louis, St Louis, Missouri, USA
| | - Jacob M Kirsch
- Department of Orthopedic Surgery, University of Michigan, Ypsilanti, Michigan, USA
| | - Asheesh Bedi
- Department of Orthopedic Surgery, University of Michigan, Ypsilanti, Michigan, USA
| | - Cristine Agresta
- School of Kinesiology, University of Michigan, Ypsilanti, Michigan, USA
| | - Michael T Freehill
- Department of Orthopedic Surgery, University of Michigan, Ypsilanti, Michigan, USA
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16
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Schleimer N, Kaspar U, Ballhausen B, Fotiadis SA, Streu JM, Kriegeskorte A, Proctor RA, Becker K. Adaption of an Episomal Antisense Silencing Approach for Investigation of the Phenotype Switch of Staphylococcus aureus Small-Colony Variants. Front Microbiol 2019; 10:2044. [PMID: 31551979 PMCID: PMC6738336 DOI: 10.3389/fmicb.2019.02044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/20/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus small-colony variants (SCVs) are associated with chronic, persistent, and relapsing courses of infection and are characterized by slow growth combined with other phenotypic and molecular traits. Although certain mechanisms have been described, the genetic basis of clinical SCVs remains often unknown. Hence, we adapted an episomal tool for rapid identification and investigation of putative SCV phenotype-associated genes via antisense gene silencing based on previously described Tnl0-encoded tet-regulatory elements. Targeting the SCV phenotype-inducing enoyl-acyl-carrier-protein reductase gene (fabI), plasmid pSN1-AS‘fabI’ was generated leading to antisense silencing, which was proven by pronounced growth retardation in liquid cultures, phenotype switch on solid medium, and 200-fold increase of antisense ‘fabI’ expression. A crucial role of TetR repression in effective regulation of the system was demonstrated. Based on the use of anhydrotetracycline as effector, an easy-to-handle one-plasmid setup was set that may be applicable to different S. aureus backgrounds and cell culture studies. However, selection of the appropriate antisense fragment of the target gene remains a critical factor for effectiveness of silencing. This inducible gene expression system may help to identify SCV phenotype-inducing genes, which is prerequisite for the development of new antistaphylococcal agents and future alternative strategies to improve treatment of therapy-refractory SCV-related infections by iatrogenically induced phenotypic switch. Moreover, it can be used as controllable phenotype switcher to examine important aspects of SCV biology in cell culture as well as in vivo.
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Affiliation(s)
- Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Ursula Kaspar
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Britta Ballhausen
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Sarah A Fotiadis
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Jessica M Streu
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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17
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Proctor R. Respiration and Small Colony Variants of Staphylococcus aureus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0069-2019. [PMID: 31198131 PMCID: PMC11257146 DOI: 10.1128/microbiolspec.gpp3-0069-2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Indexed: 12/16/2022] Open
Abstract
Respiratory mutants, both naturally occurring and genetically constructed, have taught us about the importance of metabolism in influencing virulence factor production, persistence, and antibiotic resistance. As we learn more about small colony variants, we find that Staphylococcus aureus has many pathways to produce small colony variants, although the respiratory variants are the best described clinically and in the laboratory.
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Affiliation(s)
- Richard Proctor
- Department of Medical Microbiology and Immunology University of Wisconsin School of Medicine and Public Health Madison, WI 53705
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18
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Emergence of a dalbavancin induced glycopeptide/lipoglycopeptide non-susceptible Staphylococcus aureus during treatment of a cardiac device-related endocarditis. Emerg Microbes Infect 2018; 7:202. [PMID: 30514923 PMCID: PMC6279813 DOI: 10.1038/s41426-018-0205-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/03/2018] [Accepted: 11/11/2018] [Indexed: 11/08/2022]
Abstract
In the present study, we demonstrated the emergence of dalbavancin non-susceptible and teicoplanin-resistant Staphylococcus aureus small colony variants which were selected in vivo through long-term treatment with dalbavancin. A 36-year-old man presented with a cardiac device-related S. aureus endocarditis and received long-term therapy with dalbavancin. Consecutively, two glycopeptide/lipoglycopeptide susceptible and two non-susceptible S. aureus isolates were obtained from blood cultures and the explanted pacemaker wire. The isolates were characterized by: standard typing methods, antimicrobial susceptibility testing, auxotrophic profiling, proliferation assays, scanning and transmission electron microscopy, as well as whole genome sequencing. The isolated SCVs demonstrated a vancomycin-susceptible but dalbavancin non-susceptible and teicoplanin-resistant phenotype whereof the respective MICs of the last isolate were 16- and 84-fold higher than the susceptible strains. All four strains were indistinguishable or at least closely related by standard typing methods (spa, MLST, and PFGE), and whole genome sequencing revealed only eight sequence variants. A consecutive increase in cell wall thickness (up to 2.1-fold), an impaired cell separation with incomplete or multiple cross walls and significantly reduced growth rates were observed in the present study. Therefore, the mutations in pbp2 and the DHH domain of GdpP were identified as the most probable candidates due to their implication in the biosynthesis and metabolism of the staphylococcal cell wall. For the first time, we demonstrated in vivo induced dalbavancin non-susceptible/teicoplanin resistant, but vancomycin and daptomycin susceptible S. aureus SCVs without lipopeptide or glycopeptide pretreatment, thus, indicating the emergence of a novel lipoglycopeptide resistance mechanism.
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19
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Zhang G, Zhao Y, Hayes AJ, Psaltis AJ, Wormald PJ, Vreugde S. Staphylococcus aureus small colony variants: Prevalence in chronic rhinosinusitis and induction by antibiotics. Allergy 2018; 73:2403-2405. [PMID: 30055001 DOI: 10.1111/all.13580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/06/2018] [Accepted: 07/23/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Guimin Zhang
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
- Department of Otolaryngology-Head and Neck Surgery; Tianjin First Center Hospital; Tianjin China
| | - Yin Zhao
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
- Department of Otolaryngology, Head and Neck Surgery; The Second Hospital of Jilin University; Changchun China
| | - Andrew J. Hayes
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
| | - Alkis J. Psaltis
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
| | - Peter-John Wormald
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
| | - Sarah Vreugde
- Department of Surgery, Otolaryngology-Head & Neck Surgery; The University of Adelaide; Adelaide South Australia Australia
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20
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Schleimer N, Kaspar U, Drescher M, Seggewiß J, von Eiff C, Proctor RA, Peters G, Kriegeskorte A, Becker K. The Energy-Coupling Factor Transporter Module EcfAA'T, a Novel Candidate for the Genetic Basis of Fatty Acid-Auxotrophic Small-Colony Variants of Staphylococcus aureus. Front Microbiol 2018; 9:1863. [PMID: 30154773 PMCID: PMC6102330 DOI: 10.3389/fmicb.2018.01863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/25/2018] [Indexed: 11/29/2022] Open
Abstract
Staphylococcal small-colony variants (SCVs) are invasive and persistent due to their ability to thrive intracellularly and to evade the host immune response. Thus, the course of infections due to this phenotype is often chronic, relapsing, and therapy-refractory. In order to improve treatment of patients suffering from SCV-associated infections, it is of major interest to understand triggers for the development of this phenotype, in particular for strains naturally occurring in clinical settings. Within this study, we comprehensively characterized two different Staphylococcus aureus triplets each consisting of isogenic strains comprising (i) clinically derived SCV phenotypes with auxotrophy for unsaturated fatty acids, (ii) the corresponding wild-types (WTs), and (iii) spontaneous in vitro revertants displaying the normal phenotype (REVs). Comparison of whole genomes revealed that clinical SCV isolates were closely related to their corresponding WTs and REVs showing only seven to eight alterations per genome triplet. However, both SCVs carried a mutation within the energy-coupling factor (ECF) transporter-encoding ecf module (EcfAA’T) resulting in truncated genes. In both cases, these mutations were shown to be naturally restored in the respective REVs. Since ECF transporters are supposed to be essential for optimal bacterial growth, their dysfunction might constitute another mechanism for the formation of naturally occurring SCVs. Another three triplets analyzed revealed neither mutations in the EcfAA’T nor in other FASII-related genes underlining the high diversity of mechanisms leading to the fatty acid-dependent phenotype. This is the first report on the ECF transporter as genetic basis of fatty acid–auxotrophic staphylococcal SCVs.
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Affiliation(s)
- Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Ursula Kaspar
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Mike Drescher
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Jochen Seggewiß
- Institute of Human Genetics, University Hospital Münster, Münster, Germany
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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21
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Protasova IN, Wan TW, Bakhareva NV, Hung WC, Higuchi W, Iwao Y, Yelistratova TA, Ilyenkova NA, Sokolovskaya YS, Martynova GP, Reva IV, Reva GV, Sidorenko SV, Teng LJ, Peryanova OV, Salmina AB, Yamamoto T. Molecular characterization of Streptococcus pneumoniae, particularly serotype19A/ST320, which emerged in Krasnoyarsk, Russia. Microbiol Immunol 2018; 61:359-370. [PMID: 28736993 PMCID: PMC5639370 DOI: 10.1111/1348-0421.12503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 06/30/2017] [Accepted: 07/17/2017] [Indexed: 12/18/2022]
Abstract
Streptococcus pneumoniae, a common human pathogen, colonizes the nasopharynx and causes diseases including acute otitis media (AOM). Herein, pneumococcal serotype distributions in children before and after PCV7 vaccination and in patients with pneumococcal disease in Siberian Russia (Krasnoyarsk) are reported. Analyses included antimicrobial susceptibility testing, sequence typing (ST), pulsed field gel electrophoresis, virulence‐related surface protein gene (VSG) typing with novel primers and structural analysis by scanning electron microscopy. In healthy children (HC) prior to administration of PCV7, drug‐susceptible serotype23F/ST1500 was a major pneumococcal genotype. In the PCV7 trial, multidrug‐resistant serotype19A/ST320 emerged in vaccinees after PCV7, exhibiting a PCV7‐induced serotype replacement. Multidrug‐resistant serotype19A/ST320 was evident in patients with AOM. Community‐acquired pneumonia (CAP) isolates showed genetic similarities to the AOM (ST320) genotype, constituting a common non‐invasive AOM–CAP group. In contrast, meningitis isolates were more divergent. Overall, 25 ST types were identified; five (20%) of which were Krasnoyarsk‐native. Regarding VSGs, PI‐1 (rlrA/rrgB), PI‐2 (pitA/B), psrP and cbpA were present at 54.3%, 38.6%, 48.6%, and 95.7%, respectively, with two major VSG content types, PI‐1−/PI‐2−/psrP+/cbpA+ and PI‐1+/PI‐2+/psrP‐/cbpA+, being found for HC and non‐invasive diseases, respectively. A major clone of serotype19A/ST320 (PI‐1+/PI‐2+) produced the longest pneumococcal wire (pilus) structures in colonies. ST1016 (PI‐1−/PI‐2−) in HC had HEp‐2 cell‐adherent pili. These results suggest that serotype19A/ST320 and related genotypes, with the VSG content type PI‐1+/PI‐2+/psrP−/cbpA+, emerged in vaccinees after PCV7 in Siberia, accompanying diseases in non‐vaccinated children, and that some genotypes (serotypes19A/ST320 and 18/ST1016) produced novel pneumococcal structures, predicting their roles in colony formation and adherence.
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Affiliation(s)
- Irina N Protasova
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Microbiology Krasnoyarsk State Medical University, Krasnoyarsk, Russia.,Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
| | - Tsai-Wen Wan
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | | | - Wei-Chun Hung
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Microbiology and Immunology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wataru Higuchi
- Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuhisa Iwao
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
| | | | | | | | - Galina P Martynova
- Department of Children Infectious Diseases, Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Ivan V Reva
- Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan.,Department of Clinical and Fundamental Medicine, Far Eastern Federal University School of Biomedicine, Vladivostok, Russia
| | - Galina V Reva
- Department of Clinical and Fundamental Medicine, Far Eastern Federal University School of Biomedicine, Vladivostok, Russia
| | - Sergey V Sidorenko
- Research Institute of Children Infections of Federal State Medical and Biological Agency of Russia, Saint Petersburg
| | - Lee-Jene Teng
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Olga V Peryanova
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Microbiology Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Alla B Salmina
- Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Tatsuo Yamamoto
- Russia-Japan Center of Microbiology, Metagenomics and Infectious Diseases, Krasnoyarsk, Russia.,Department of Epidemiology, Genomics, and Evolution, International Medical Education and Research, Center Niigata, Japan
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22
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Genetic Basis of Emerging Vancomycin, Linezolid, and Daptomycin Heteroresistance in a Case of Persistent Enterococcus faecium Bacteremia. Antimicrob Agents Chemother 2018; 62:AAC.02007-17. [PMID: 29339387 PMCID: PMC5913925 DOI: 10.1128/aac.02007-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/20/2017] [Indexed: 02/07/2023] Open
Abstract
Whole-genome sequencing was used to examine a persistent Enterococcus faecium bacteremia that acquired heteroresistance to three antibiotics in response to prolonged multidrug therapy. A comparison of the complete genomes before and after each change revealed the emergence of known resistance determinants for vancomycin and linezolid and suggested that a novel mutation in fabF, encoding a fatty acid synthase, was responsible for daptomycin nonsusceptibility. Plasmid recombination contributed to the progressive loss of vancomycin resistance after withdrawal of the drug.
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23
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Morvan C, Halpern D, Kénanian G, Pathania A, Anba-Mondoloni J, Lamberet G, Gruss A, Gloux K. The Staphylococcus aureus FASII bypass escape route from FASII inhibitors. Biochimie 2017; 141:40-46. [PMID: 28728970 DOI: 10.1016/j.biochi.2017.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/13/2017] [Indexed: 01/05/2023]
Abstract
Antimicrobials targeting the fatty acid synthesis (FASII) pathway are being developed as alternative treatments for bacterial infections. Emergence of resistance to FASII inhibitors was mainly considered as a consequence of mutations in the FASII target genes. However, an alternative and efficient anti-FASII resistance strategy, called here FASII bypass, was uncovered. Bacteria that bypass FASII incorporate exogenous fatty acids in membrane lipids, and thus dispense with the need for FASII. This strategy is used by numerous Gram-positive low GC % bacteria, including streptococci, enterococci, and staphylococci. Some bacteria repress FASII genes once fatty acids are available, and "constitutively" shift to FASII bypass. Others, such as the major pathogen Staphylococcus aureus, can undergo high frequency mutations that favor FASII bypass. This capacity is particularly relevant during infection, as the host supplies the fatty acids needed for bacteria to bypass FASII and thus become resistant to FASII inhibitors. Screenings for anti-FASII resistance in the presence of exogenous fatty acids confirmed that FASII bypass confers anti-FASII resistance among clinical and veterinary isolates. Polymorphisms in S. aureus FASII initiation enzymes favor FASII bypass, possibly by increasing availability of acyl-carrier protein, a required intermediate. Here we review FASII bypass and consequences in light of proposed uses of anti-FASII to treat infections, with a focus on FASII bypass in S. aureus.
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Affiliation(s)
- Claire Morvan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - David Halpern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Gérald Kénanian
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Amit Pathania
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Jamila Anba-Mondoloni
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Gilles Lamberet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Alexandra Gruss
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
| | - Karine Gloux
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
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24
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Abstract
Staphylococcus aureus is known to generate small colony variants (SCVs) that are resistant to aminoglycoside antibiotics and can cause persistent and recurrent infections. The SCV phenotype is unstable, and compensatory mutations lead to restored growth, usually with loss of resistance. However, the evolution of improved growth, by mechanisms that avoid loss of antibiotic resistance, is very poorly understood. By selection with serial passaging, we isolated and characterized different classes of extragenic suppressor mutations that compensate for the slow growth of small colony variants. Compensation occurs by two distinct bypass mechanisms: (i) translational suppression of the initial SCV mutation by mutant tRNAs, ribosomal protein S5, or release factor 2 and (ii) mutations that cause the constitutive activation of the SrrAB global transcriptional regulation system. Although compensation by translational suppression increases growth rate, it also reduces antibiotic susceptibility, thus restoring a pseudo-wild-type phenotype. In contrast, an evolutionary pathway that compensates for the SCV phenotype by activation of SrrAB increases growth rate without loss of antibiotic resistance. RNA sequence analysis revealed that mutations activating the SrrAB pathway cause upregulation of genes involved in peptide transport and in the fermentation pathways of pyruvate to generate ATP and NAD+, thus explaining the increased growth. By increasing the growth rate of SCVs without the loss of aminoglycoside resistance, compensatory evolution via the SrrAB activation pathway represents a threat to effective antibiotic therapy of staphylococcal infections.IMPORTANCE Small colony variants (SCVs) of Staphylococcus aureus are a significant clinical problem, causing persistent and antibiotic-resistant infections. However, SCVs are unstable and can rapidly evolve growth-compensated mutants. Previous data suggested that growth compensation only occurred with the loss of antibiotic resistance. We have used selection with serial passaging to uncover four distinct pathways of growth compensation accessible to SCVs. Three of these paths (reversion, intragenic suppression, and translational suppression) increase growth at the expense of losing antibiotic resistance. The fourth path activates an alternative transcriptional program and allows the bacteria to produce the extra ATP required to support faster growth, without losing antibiotic resistance. The importance of this work is that it shows that drug-resistant SCVs can evolve faster growth without losing antibiotic resistance.
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25
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Clinical Relevance of Type II Fatty Acid Synthesis Bypass in Staphylococcus aureus. Antimicrob Agents Chemother 2017; 61:AAC.02515-16. [PMID: 28193654 DOI: 10.1128/aac.02515-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/06/2017] [Indexed: 12/14/2022] Open
Abstract
The need for new antimicrobials to treat bacterial infections has led to the use of type II fatty acid synthesis (FASII) enzymes as front-line targets. However, recent studies suggest that FASII inhibitors may not work against the opportunist pathogen Staphylococcus aureus, as environmental fatty acids favor emergence of multi-anti-FASII resistance. As fatty acids are abundant in the host and one FASII inhibitor, triclosan, is widespread, we investigated whether fatty acid pools impact resistance in clinical and veterinary S. aureus isolates. Simple addition of fatty acids to the screening medium led to a 50% increase in triclosan resistance, as tested in 700 isolates. Moreover, nonculturable triclosan-resistant fatty acid auxotrophs, which escape detection under routine conditions, were uncovered in primary patient samples. FASII bypass in selected isolates correlated with polymorphisms in the acc and fabD loci. We conclude that fatty-acid-dependent strategies to escape FASII inhibition are common among S. aureus isolates and correlate with anti-FASII resistance and emergence of nonculturable variants.
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26
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Environmental fatty acids enable emergence of infectious Staphylococcus aureus resistant to FASII-targeted antimicrobials. Nat Commun 2016; 7:12944. [PMID: 27703138 PMCID: PMC5059476 DOI: 10.1038/ncomms12944] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 08/16/2016] [Indexed: 01/11/2023] Open
Abstract
The bacterial pathway for fatty acid biosynthesis, FASII, is a target for development of new anti-staphylococcal drugs. This strategy is based on previous reports indicating that self-synthesized fatty acids appear to be indispensable for Staphylococcus aureus growth and virulence, although other bacteria can use exogenous fatty acids to compensate FASII inhibition. Here we report that staphylococci can become resistant to the FASII-targeted inhibitor triclosan via high frequency mutations in fabD, one of the FASII genes. The fabD mutants can be conditional for FASII and not require exogenous fatty acids for normal growth, and can use diverse fatty acid combinations (including host fatty acids) when FASII is blocked. These mutants show cross-resistance to inhibitors of other FASII enzymes and are infectious in mice. Clinical isolates bearing fabD polymorphisms also bypass FASII inhibition. We propose that fatty acid-rich environments within the host, in the presence of FASII inhibitors, might favour the emergence of staphylococcal strains displaying resistance to multiple FASII inhibitors. The bacterial pathway for fatty acid biosynthesis, FASII, is a target for development of new anti-staphylococcal drugs. Here, Morvan et al. show that exogenous fatty acids can favour the emergence of staphylococcal strains displaying resistance to multiple FASII inhibitors.
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