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Saiman L, Waters V, LiPuma JJ, Hoffman LR, Alby K, Zhang SX, Yau YC, Downey DG, Sermet-Gaudelus I, Bouchara JP, Kidd TJ, Bell SC, Brown AW. Practical Guidance for Clinical Microbiology Laboratories: Updated guidance for processing respiratory tract samples from people with cystic fibrosis. Clin Microbiol Rev 2024; 37:e0021521. [PMID: 39158301 DOI: 10.1128/cmr.00215-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2024] Open
Abstract
SUMMARYThis guidance presents recommendations for clinical microbiology laboratories for processing respiratory samples from people with cystic fibrosis (pwCF). Appropriate processing of respiratory samples is crucial to detect bacterial and fungal pathogens, guide treatment, monitor the epidemiology of cystic fibrosis (CF) pathogens, and assess therapeutic interventions. Thanks to CF transmembrane conductance regulator modulator therapy, the health of pwCF has improved, but as a result, fewer pwCF spontaneously expectorate sputum. Thus, the collection of sputum samples has decreased, while the collection of other types of respiratory samples such as oropharyngeal and bronchoalveolar lavage samples has increased. To optimize the detection of microorganisms, including Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae, and Burkholderia cepacia complex; other less common non-lactose fermenting Gram-negative bacilli, e.g., Stenotrophomonas maltophilia, Inquilinus, Achromobacter, Ralstonia, and Pandoraea species; and yeasts and filamentous fungi, non-selective and selective culture media are recommended for all types of respiratory samples, including samples obtained from pwCF after lung transplantation. There are no consensus recommendations for laboratory practices to detect, characterize, and report small colony variants (SCVs) of S. aureus, although studies are ongoing to address the potential clinical impact of SCVs. Accurate identification of less common Gram-negative bacilli, e.g., S. maltophilia, Inquilinus, Achromobacter, Ralstonia, and Pandoraea species, as well as yeasts and filamentous fungi, is recommended to understand their epidemiology and clinical importance in pwCF. However, conventional biochemical tests and automated platforms may not accurately identify CF pathogens. MALDI-TOF MS provides excellent genus-level identification, but databases may lack representation of CF pathogens to the species-level. Thus, DNA sequence analysis should be routinely available to laboratories for selected clinical circumstances. Antimicrobial susceptibility testing (AST) is not recommended for every routine surveillance culture obtained from pwCF, although selective AST may be helpful, e.g., for unusual pathogens or exacerbations unresponsive to initial therapy. While this guidance reflects current care paradigms for pwCF, recommendations will continue to evolve as CF research expands the evidence base for laboratory practices.
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Affiliation(s)
- Lisa Saiman
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
- Department of Infection Prevention and Control, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Valerie Waters
- Division of Infectious Diseases, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - John J LiPuma
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Lucas R Hoffman
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Kevin Alby
- Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Sean X Zhang
- Division of Medical Microbiology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yvonne C Yau
- Division of Microbiology, Department of Paediatric Laboratory Medicine, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Damian G Downey
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University, Belfast, Ireland
| | | | - Jean-Philippe Bouchara
- University of Angers-University of Brest, Infections Respiratoires Fongiques, Angers, France
| | - Timothy J Kidd
- Microbiology Division, Pathology Queensland Central Laboratory, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Scott C Bell
- The Prince Charles Hospital, Faculty of Medicine, The University of Queensland, Brisbane, Australia
- The Translational Research Institute, Brisbane, Australia
| | - A Whitney Brown
- Cystic Fibrosis Foundation, Bethesda, Maryland, USA
- Inova Advanced Lung Disease and Transplant Program, Inova Fairfax Hospital, Falls Church, Virginia, USA
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Zhou J, He C, Yang H, Shu W, Liu Q. Integrative omics analysis reveals insights into small colony variants of Staphylococcus aureus induced by sulfamethoxazole-trimethoprim. BMC Microbiol 2024; 24:212. [PMID: 38877418 PMCID: PMC11179224 DOI: 10.1186/s12866-024-03364-8] [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: 09/05/2023] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Long-term treatment with trimethoprim-sulfamethoxazole (SXT) can lead to the formation of small-colony variants (SCVs) of Staphylococcus aureus. However, the mechanism behind SCVs formation remains poorly understood. In this study, we explored the phenotype and omics-based characterization of S. aureus SCVs induced by SXT and shed light on the potential causes of SCV formation. METHODS Stable SCVs were obtained by continuously treating S. aureus isolates using 12/238 µg/ml of SXT, characterized by growth kinetics, antibiotic susceptibility testing, and auxotrophism test. Subsequently, a pair of representative strains (SCV and its parental strain) were selected for genomic, transcriptomic and metabolomic analysis. RESULTS Three stable S. aureus SCVs were successfully screened and proven to be homologous to their corresponding parental strains. Phenotypic tests showed that all SCVs were non-classical mechanisms associated with impaired utilization of menadione, heme and thymine, and exhibited slower growth and higher antibiotic minimum inhibitory concentrations (MICs), compared to their corresponding parental strains. Genomic data revealed 15 missense mutations in 13 genes in the representative SCV, which were involved in adhesion, intramolecular phosphate transfer on ribose, transport pathways, and phage-encoded proteins. The combination analysis of transcriptome and metabolome identified 35 overlapping pathways possible associated with the phenotype switching of S. aureus. These pathways mainly included changes in metabolism, such as purine metabolism, pyruvate metabolism, amino acid metabolism, and ABC transporters, which could play a crucial role in promoting SCVs development by affecting nucleic acid synthesis and energy metabolism in bacteria. CONCLUSION This study provides profound insights into the causes of S. aureus SCV formation induced by SXT. The findings may offer valuable clues for developing new strategies to combat S. aureus SCV infections.
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Affiliation(s)
- Jingwen Zhou
- Department of Clinical Laboratory, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 274 Zhijiang Middle Rd, Shanghai, 200071, People's Republic of China
| | - Chunyan He
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Han Yang
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wen Shu
- Department of Clinical Laboratory, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qingzhong Liu
- Department of Clinical Laboratory, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 274 Zhijiang Middle Rd, Shanghai, 200071, People's Republic of China.
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Funke FJ, Schlee S, Sterner R. Validation of aminodeoxychorismate synthase and anthranilate synthase as novel targets for bispecific antibiotics inhibiting conserved protein-protein interactions. Appl Environ Microbiol 2024; 90:e0057224. [PMID: 38700332 PMCID: PMC11107160 DOI: 10.1128/aem.00572-24] [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: 03/28/2024] [Accepted: 04/08/2024] [Indexed: 05/05/2024] Open
Abstract
Multi-resistant bacteria are a rapidly emerging threat to modern medicine. It is thus essential to identify and validate novel antibacterial targets that promise high robustness against resistance-mediating mutations. This can be achieved by simultaneously targeting several conserved function-determining protein-protein interactions in enzyme complexes from prokaryotic primary metabolism. Here, we selected two evolutionary related glutamine amidotransferase complexes, aminodeoxychorismate synthase and anthranilate synthase, that are required for the biosynthesis of folate and tryptophan in most prokaryotic organisms. Both enzymes rely on the interplay of a glutaminase and a synthase subunit that is conferred by a highly conserved subunit interface. Consequently, inhibiting subunit association in both enzymes by one competing bispecific inhibitor has the potential to suppress bacterial proliferation. We comprehensively verified two conserved interface hot-spot residues as potential inhibitor-binding sites in vitro by demonstrating their crucial role in subunit association and enzymatic activity. For in vivo target validation, we generated genomically modified Escherichia coli strains in which subunit association was disrupted by modifying these central interface residues. The growth of such strains was drastically retarded on liquid and solid minimal medium due to a lack of folate and tryptophan. Remarkably, the bacteriostatic effect was observed even in the presence of heat-inactivated human plasma, demonstrating that accessible host metabolite concentrations do not compensate for the lack of folate and tryptophan within the tested bacterial cells. We conclude that a potential inhibitor targeting both enzyme complexes will be effective against a broad spectrum of pathogens and offer increased resilience against antibiotic resistance. IMPORTANCE Antibiotics are indispensable for the treatment of bacterial infections in human and veterinary medicine and are thus a major pillar of modern medicine. However, the exposure of bacteria to antibiotics generates an unintentional selective pressure on bacterial assemblies that over time promotes the development or acquisition of resistance mechanisms, allowing pathogens to escape the treatment. In that manner, humanity is in an ever-lasting race with pathogens to come up with new treatment options before resistances emerge. In general, antibiotics with novel modes of action require more complex pathogen adaptations as compared to chemical derivates of existing entities, thus delaying the emergence of resistance. In this contribution, we use modified Escherichia coli strains to validate two novel targets required for folate and tryptophan biosynthesis that can potentially be targeted by one and the same bispecific protein-protein interaction inhibitor and promise increased robustness against bacterial resistances.
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Affiliation(s)
- Franziska Jasmin Funke
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sandra Schlee
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
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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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Tsujino Y, Ogawa E, Ito K. Thymidine-dependent small-colony variants of Staphylococcus aureus isolated from infective endocarditis in a postlung transplant patient. Transpl Infect Dis 2024; 26:e14176. [PMID: 37853647 DOI: 10.1111/tid.14176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Affiliation(s)
- Yuina Tsujino
- Department of General Pediatrics, Aichi Children's Health and Medical Center, Obu, Japan
| | - Eiki Ogawa
- Department of General Pediatrics, Aichi Children's Health and Medical Center, Obu, Japan
| | - Kenta Ito
- Department of General Pediatrics, Aichi Children's Health and Medical Center, Obu, Japan
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Acosta IC, Alonzo F. The Intersection between Bacterial Metabolism and Innate Immunity. J Innate Immun 2023; 15:782-803. [PMID: 37899025 PMCID: PMC10663042 DOI: 10.1159/000534872] [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: 09/14/2023] [Accepted: 10/25/2023] [Indexed: 10/31/2023] Open
Abstract
BACKGROUND The innate immune system is the first line of defense against microbial pathogens and is essential for maintaining good health. If pathogens breach innate barriers, the likelihood of infection is significantly increased. Many bacterial pathogens pose a threat to human health on account of their ability to evade innate immunity and survive in growth-restricted environments. These pathogens have evolved sophisticated strategies to obtain nutrients as well as manipulate innate immune responses, resulting in disease or chronic infection. SUMMARY The relationship between bacterial metabolism and innate immunity is complex. Although aspects of bacterial metabolism can be beneficial to the host, particularly those related to the microbiota and barrier integrity, others can be harmful. Several bacterial pathogens harness metabolism to evade immune responses and persist during infection. The study of these adaptive traits provides insight into the roles of microbial metabolism in pathogenesis that extend beyond energy balance. This review considers recent studies on bacterial metabolic pathways that promote infection by circumventing several facets of the innate immune system. We also discuss relationships between innate immunity and antibiotics and highlight future directions for research in this field. KEY MESSAGES Pathogenic bacteria have a remarkable capacity to harness metabolism to manipulate immune responses and promote pathogenesis. While we are beginning to understand the multifaceted and complex metabolic adaptations that occur during infection, there is still much to uncover with future research.
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Affiliation(s)
- Ivan C Acosta
- Department of Microbiology and Immunology, University of Illinois at Chicago - College of Medicine, Chicago, Illinois, USA
| | - Francis Alonzo
- Department of Microbiology and Immunology, University of Illinois at Chicago - College of Medicine, Chicago, Illinois, USA
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Ryan H, Ballard E, Stockwell RE, Duplancic C, Thomson RM, Smith K, Bell SC. A systematic review of the clinical impact of small colony variants in patients with cystic fibrosis. BMC Pulm Med 2023; 23:323. [PMID: 37658311 PMCID: PMC10474644 DOI: 10.1186/s12890-023-02611-4] [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: 01/16/2023] [Accepted: 08/24/2023] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND Cystic fibrosis (CF) is a life-limiting disorder that is characterised by respiratory tract inflammation that is mediated by a range of microbial pathogens. Small colony variants (SCVs) of common respiratory pathogens are being increasingly recognised in CF. The aim of this systematic review is to investigate the prevalence of SCVs, clinical characteristics and health outcomes for patients with CF, and laboratory diagnostic features of SCVs compared to non-small colony variants (NCVs) for a range of Gram-positive and Gram-negative respiratory pathogens. METHODS A literature search was conducted (PubMed, Web of Science, Embase and Scopus) in April 2020 to identify articles of interest. Data pertaining to demographic characteristics of participants, diagnostic criteria of SCVs, SCV prevalence and impact on lung function were extracted from included studies for analysis. RESULTS Twenty-five of 673 studies were included in the systematic review. Individuals infected with SCVs of Staphylococcus aureus (S. aureus) were more likely to have had prior use of the broad-spectrum antibiotic trimethoprim sulfamethoxazole (p < 0.001), and the prevalence of SCVs in patients infected with S. aureus was estimated to be 19.3% (95% CI: 13.5% to 25.9%). Additionally, patients infected with SCVs of Gram-negative and Gram-positive pathogens were identified to have a lower forced expiratory volume in one second percentage predicted (-16.8, 95% CI: -23.2 to -10.4) than those infected by NCVs. Gram-positive SCVs were commonly described as small and non-haemolytic, grown on Mannitol salt or blood agar for 24 h at 35°C and confirmed using tube coagulase testing. CONCLUSION The findings of this systematic review demonstrate that SCVs of S. aureus have a high prevalence in the CF community, and that the occurrence of SCVs in Gram-positive and Gram-negative pathogens is linked to poorer respiratory function. Further investigation is necessary to determine the effect of infection by SCVs on the CF population.
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Affiliation(s)
- Harrigan Ryan
- Centre for Children's Health Research, Faculty of Medicine, The University of Queensland, South Brisbane, QLD, Australia
| | - Emma Ballard
- Statistics Unit, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Rebecca E Stockwell
- Centre for Children's Health Research, Faculty of Medicine, The University of Queensland, South Brisbane, QLD, Australia
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, QLD, Australia
| | - Christine Duplancic
- Centre for Children's Health Research, Faculty of Medicine, The University of Queensland, South Brisbane, QLD, Australia
| | - Rachel M Thomson
- Respiratory Research Group, Gallipoli Medical Research Foundation, Greenslopes, QLD, Australia
| | - Kimberley Smith
- Centre for Children's Health Research, Faculty of Medicine, The University of Queensland, South Brisbane, QLD, Australia
| | - Scott C Bell
- Centre for Children's Health Research, Faculty of Medicine, The University of Queensland, South Brisbane, QLD, Australia.
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, QLD, Australia.
- Translational Research Institute, Woolloongabba, QLD, Australia.
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Millette G, Séguin DL, Isabelle C, Chamberland S, Lucier JF, Rodrigue S, Cantin AM, Malouin F. Staphylococcus aureus Small-Colony Variants from Airways of Adult Cystic Fibrosis Patients as Precursors of Adaptive Antibiotic-Resistant Mutations. Antibiotics (Basel) 2023; 12:1069. [PMID: 37370388 PMCID: PMC10294822 DOI: 10.3390/antibiotics12061069] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Prototypic Staphylococcus aureus and their small-colony variants (SCVs) are predominant in cystic fibrosis (CF), but the interdependence of these phenotypes is poorly understood. We characterized S. aureus isolates from adult CF patients over several years. Of 18 S. aureus-positive patients (58%), 13 (72%) were positive for SCVs. Characterization included genotyping, SCCmec types, auxotrophy, biofilm production, antibiotic susceptibilities and tolerance, and resistance acquisition rates. Whole-genome sequencing revealed that several patients were colonized with prototypical and SCV-related clones. Some clonal pairs showed acquisition of aminoglycoside resistance that was not explained by aminoglycoside-modifying enzymes, suggesting a mutation-based process. The characteristics of SCVs that could play a role in resistance acquisition were thus investigated further. For instance, SCV isolates produced more biofilm (p < 0.05) and showed a higher survival rate upon exposure to ciprofloxacin and vancomycin compared to their prototypic associated clones. SCVs also developed spontaneous rifampicin resistance mutations at a higher frequency. Accordingly, a laboratory-derived SCV (ΔhemB) acquired resistance to ciprofloxacin and gentamicin faster than its parent counterpart after serial passages in the presence of sub-inhibitory concentrations of antibiotics. These results suggest a role for SCVs in the establishment of persistent antibiotic-resistant clones in adult CF patients.
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Affiliation(s)
- Guillaume Millette
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - David Lalonde Séguin
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - Charles Isabelle
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - Suzanne Chamberland
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - Jean-François Lucier
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - Sébastien Rodrigue
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
| | - André M. Cantin
- Service de Pneumologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada;
| | - François Malouin
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (G.M.); (D.L.S.); (C.I.); (S.C.); (J.-F.L.); (S.R.)
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Jin Q, Xie X, Zhai Y, Zhang H. Mechanisms of folate metabolism-related substances affecting Staphylococcus aureus infection. Int J Med Microbiol 2023; 313:151577. [PMID: 36841056 DOI: 10.1016/j.ijmm.2023.151577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 01/28/2023] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Staphylococcus aureus (S. aureus) is one of the critical clinical pathogens which can cause multiple diseases ranging from skin infections to fatal sepsis. S. aureus is generally considered to be an extracellular pathogen. However, more and more evidence has shown that S. aureus can survive inside various cells. Folate plays an essential role in multiple life activities, including the conversion of serine and glycine, the remethylation of homocysteine to methionine, and the de novo synthesis of purine /dTMP, et al. More and more studies reported that S. aureus intracellular infection requires the involvement of folate metabolism. This review focused on the mechanisms of folate metabolism and related substances affecting S. aureus infection. Loss of tetrahydrofolic acid (THF)-dependent dTMP directly inhibits the nucleotide synthesis pathway of the S. aureus due to pabA deficiency. Besides, trimethoprim-sulfamethoxazole (TMP/SMX), a potent antibiotic that treats S. aureus infections, interferes in the process of the folate mechanism and leads to the production of thymidine-dependent small-colony variants (TD-SCVs). In addition, S. aureus is resistant to lysostaphin in the presence of serine hydroxymethyltransferase (SHMT). We provide new insights for understanding the molecular pathogenesis of S. aureus infection.
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Affiliation(s)
- Qiyuan Jin
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaolu Xie
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Yaxuan Zhai
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Haifang Zhang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China.
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Acute Infection with a Tobramycin-Induced Small Colony Variant of Staphylococcus aureus Causes Increased Inflammation in the Cystic Fibrosis Rat Lung. Infect Immun 2022; 90:e0023722. [PMID: 36165627 PMCID: PMC9671023 DOI: 10.1128/iai.00237-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cystic fibrosis (CF) disease is characterized by lifelong infections with pathogens such as Staphylococcus aureus, leading to eventual respiratory failure. Small colony variants (SCVs) of S. aureus have been linked to worse clinical outcomes for people with CF. Current studies of SCV pathology in vivo are limited, and it remains unclear whether SCVs directly impact patient outcomes or are a result of late-stage CF disease. To investigate this, we generated a stable menadione-auxotrophic SCV strain by serially passaging a CF isolate of S. aureus with tobramycin, an aminoglycoside antibiotic commonly administered for coinfecting Pseudomonas aeruginosa. This SCV was tobramycin resistant and showed increased tolerance to the anti-staphylococcal combination therapy sulfamethoxazole-trimethoprim. To better understand the dynamics of SCV infections in vivo, we infected CF rats with this strain compared with its normal colony variant (NCV). Analysis of bacterial burden at 3 days postinfection indicated that NCVs and SCVs persisted equally well in the lungs, but SCV infections ultimately led to increased weight loss and neutrophilic inflammation. Additionally, cellular and histopathological analyses showed that in CF rats, SCV infections yielded a lower macrophage response. Overall, these findings indicate that SCV infections may directly contribute to lung disease progression in people with CF.
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Jakovljev A, Afset JE, Haugum K, Steinum HO, Gresdal Rønning T, Samuelsen Ø, Ås CG. Phenotypic and genotypic characterisation of thymine auxotrophy in Escherichia coli isolated from a patient with recurrent bloodstream infection. PLoS One 2022; 17:e0270256. [PMID: 35802671 PMCID: PMC9269972 DOI: 10.1371/journal.pone.0270256] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/08/2022] [Indexed: 01/05/2023] Open
Abstract
INTRODUCTION Thymine auxotrophic in vitro mutants of Escherichia coli were first reported in the mid-20th century. Later, thymine-dependent clinical strains of E. coli as well as other Enterobacterales, Enterococcus faecalis and Staphylococcus aureus have been recognized as the cause of persistent and recurrent infections. OBJECTIVES The aim of this study was to characterize the phenotype and investigate the molecular basis of thymine auxotrophy in ten E. coli isolates obtained at different time points from a patient with recurrent bloodstream infection (BSI) due to a chronic aortic graft infection treated with Trimethoprim/sulfamethoxazole (TMP-SMX). METHODS Clinical data was obtained from hospital records. Growth characterization and antimicrobial susceptibility testing to TMP-SMX was performed on M9 agar and in MH broth with different thymine concentrations (0.5, 2, 5, 10 and 20 μg/mL), on Mueller-Hinton (MH) and blood agar. Whole genome sequencing (WGS) was performed on all E. coli isolates. RESULTS E. coli were isolated from ten consecutive BSI episodes from a patient with chronic aortic graft infection. Six of these isolates were resistant to TMP-SMX when assayed on blood agar. Growth experiments with added thymine confirmed that these isolates were thymine-dependent (thy-), and revealed growth defects (slower growth rate and smaller colony size) in these isolates relative to thy+ isolates (n = 4). WGS indicated that all isolates were of the same clonal lineage of sequence type 7358. Genomic analysis revealed a G172C substitution in thyA in all TMP-SMX resistant isolates, while mutations affecting genes involved in the deoxyribose salvage pathway (deoB and deoC) were identified in eight isolates. CONCLUSION This case highlights the risk of resistance development to TMP-SMX, especially for long-term treatment, and the possible pitfalls in detection of growth-deficient subpopulations from chronic infections, which could lead to treatment failure.
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Affiliation(s)
- Aleksandra Jakovljev
- Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Jan Egil Afset
- Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kjersti Haugum
- Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Harald Otto Steinum
- Department of Infectious Diseases, Clinic of Internal Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Torunn Gresdal Rønning
- Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ørjan Samuelsen
- Department of Microbiology and Infection Control, Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, University Hospital of North Norway, Tromsø, Norway
- Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - Christina Gabrielsen Ås
- Department of Medical Microbiology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- * E-mail:
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12
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Acosta IC, Alonzo F. Antibiotic treatment ignites a fire that lasts. Cell Host Microbe 2022; 30:897-899. [DOI: 10.1016/j.chom.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Ramond E, Lepissier A, Ding X, Bouvier C, Tan X, Euphrasie D, Monbernard P, Dupuis M, Saubaméa B, Nemazanyy I, Nassif X, Ferroni A, Sermet-Gaudelus I, Charbit A, Coureuil M, Jamet A. Lung-adapted Staphylococcus aureus isolates with dysfunctional agr system trigger a proinflammatory response. J Infect Dis 2022; 226:1276-1285. [PMID: 35524969 DOI: 10.1093/infdis/jiac191] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Staphylococcus aureus (Sa) dominates the lung microbiota of Cystic Fibrosis (CF) children and persistent clones are able to establish chronic infection for years, having a direct deleterious impact on lung function. However, in this context, the exact contribution of Sa to the decline in respiratory function in CF children is not elucidated. METHODS To investigate the contribution of persistent S. aureus clones in CF disease, we undertook the analysis of sequential isogenic isolates recovered from 15 young CF patients. RESULTS Using an Air-Liquid infection model, we observed a strong correlation between Sa adaption in the lung (late isolates), low toxicity and pro-inflammatory cytokine secretion. Conversely, early isolates appeared to be highly cytotoxic but did not promote cytokine secretion. We found that cytokine secretion was dependent on Staphylococcal protein A (Spa), which was selectively expressed in late compared to early isolates as a consequence of dysfunctional agr quorum-sensing system. Finally, we demonstrated the involvement of TNF-α receptor 1 signaling in the inflammatory response of airway epithelial cells to these lung-adapted Sa isolates. CONCLUSION Our results suggest an unexpected direct role of bacterial lung adaptation in the progression of chronic lung disease by promoting a pro-inflammatory response through acquired agr dysfunction.
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Affiliation(s)
- Elodie Ramond
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Agathe Lepissier
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Epithelial channellopathies, Cystic Fibrosis and other diseases, Paris, France
| | - Xiongqi Ding
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Clémence Bouvier
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Xin Tan
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Daniel Euphrasie
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Pierre Monbernard
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Marion Dupuis
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Bruno Saubaméa
- Cellular and Molecular Imaging facility, INSERM US25, UMS3612 CNRS, Faculté de Pharmacie de Paris, Université de Paris, Paris, France
| | - Ivan Nemazanyy
- Plateforme Etude du métabolisme, Structure Fédérative de Recherche Necker INSERM US24-CNRS UMS 3633, Paris, France
| | - Xavier Nassif
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Agnès Ferroni
- Department of Clinical Microbiology, Necker-Enfants Malades Hospital, AP-HP Centre Université de Paris, Paris, France
| | - Isabelle Sermet-Gaudelus
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Epithelial channellopathies, Cystic Fibrosis and other diseases, Paris, France
| | - Alain Charbit
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Mathieu Coureuil
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Anne Jamet
- Université de Paris; Faculté de Médecine, Paris, France.,INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France.,Department of Clinical Microbiology, Necker-Enfants Malades Hospital, AP-HP Centre Université de Paris, Paris, France
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14
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Tang Q, Precit MR, Thomason MK, Blanc SF, Ahmed-Qadri F, McFarland AP, Wolter DJ, Hoffman LR, Woodward JJ. Thymidine starvation promotes c-di-AMP-dependent inflammation during pathogenic bacterial infection. Cell Host Microbe 2022; 30:961-974.e6. [PMID: 35439435 DOI: 10.1016/j.chom.2022.03.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/01/2022] [Accepted: 03/23/2022] [Indexed: 11/03/2022]
Abstract
Antimicrobials can impact bacterial physiology and host immunity with negative treatment outcomes. Extensive exposure to antifolate antibiotics promotes thymidine-dependent Staphylococcus aureus small colony variants (TD-SCVs), commonly associated with worse clinical outcomes. We show that antibiotic-mediated disruption of thymidine synthesis promotes elevated levels of the bacterial second messenger cyclic di-AMP (c-di-AMP), consequently inducing host STING activation and inflammation. An initial antibiotic screen in Firmicutes revealed that c-di-AMP production was largely driven by antifolate antibiotics targeting dihydrofolate reductase (DHFR), which promotes folate regeneration required for thymidine biosynthesis. Additionally, TD-SCVs exhibited excessive c-di-AMP production and STING activation in a thymidine-dependent manner. Murine lung infection with TD-SCVs revealed STING-dependent elevation of proinflammatory cytokines, causing higher airway neutrophil infiltration and activation compared with normal-colony S. aureus and hemin-dependent SCVs. Collectively, our results suggest that thymidine metabolism disruption in Firmicutes leads to elevated c-di-AMP-mediated STING-dependent inflammation, with potential impacts on antibiotic usage and infection outcomes.
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Affiliation(s)
- Qing Tang
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Mimi R Precit
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Maureen K Thomason
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Sophie F Blanc
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Fariha Ahmed-Qadri
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Adelle P McFarland
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA
| | - Daniel J Wolter
- Department of Pediatrics, University of Washington, Seattle, WA 98105, USA; Pulmonary and Sleep Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Lucas R Hoffman
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA; Department of Pediatrics, University of Washington, Seattle, WA 98105, USA; Pulmonary and Sleep Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA 98105, USA.
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15
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Biswas L, Götz F. Molecular Mechanisms of Staphylococcus and Pseudomonas Interactions in Cystic Fibrosis. Front Cell Infect Microbiol 2022; 11:824042. [PMID: 35071057 PMCID: PMC8770549 DOI: 10.3389/fcimb.2021.824042] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/16/2021] [Indexed: 11/15/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive genetic disorder that is characterized by recurrent and chronic infections of the lung predominantly by the opportunistic pathogens, Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. While S. aureus is the main colonizing bacteria of the CF lungs during infancy and early childhood, its incidence declines thereafter and infections by P. aeruginosa become more prominent with increasing age. The competitive and cooperative interactions exhibited by these two pathogens influence their survival, antibiotic susceptibility, persistence and, consequently the disease progression. For instance, P. aeruginosa secretes small respiratory inhibitors like hydrogen cyanide, pyocyanin and quinoline N-oxides that block the electron transport pathway and suppress the growth of S. aureus. However, S. aureus survives this respiratory attack by adapting to respiration-defective small colony variant (SCV) phenotype. SCVs cause persistent and recurrent infections and are also resistant to antibiotics, especially aminoglycosides, antifolate antibiotics, and to host antimicrobial peptides such as LL-37, human β-defensin (HBD) 2 and HBD3; and lactoferricin B. The interaction between P. aeruginosa and S. aureus is multifaceted. In mucoid P. aeruginosa strains, siderophores and rhamnolipids are downregulated thus enhancing the survival of S. aureus. Conversely, protein A from S. aureus inhibits P. aeruginosa biofilm formation while protecting both P. aeruginosa and S. aureus from phagocytosis by neutrophils. This review attempts to summarize the current understanding of the molecular mechanisms that drive the competitive and cooperative interactions between S. aureus and P. aeruginosa in the CF lungs that could influence the disease outcome.
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Affiliation(s)
- Lalitha Biswas
- Centre for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi, India
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
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16
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Nurjadi D, Chanthalangsy Q, Zizmann E, Stuermer V, Moll M, Klein S, Boutin S, Heeg K, Zanger P. Phenotypic Detection of Hemin-Inducible Trimethoprim-Sulfamethoxazole Heteroresistance in Staphylococcus aureus. Microbiol Spectr 2021; 9:e0151021. [PMID: 34704796 PMCID: PMC8549745 DOI: 10.1128/spectrum.01510-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022] Open
Abstract
Trimethoprim-sulfamethoxazole (SXT) is a valuable second-line antimicrobial agent to treat methicillin-resistant Staphylococcus aureus infections. Discrepancies between various antibiotic susceptibility testing (AST) methods for SXT susceptibility in S. aureus have been described. Here, we describe a hemin-inducible heteroresistance phenotype in S. aureus. We compared the results of the Vitek 2 AST on a set of 95 S. aureus clinical isolates with broth microdilution, disk diffusion using standard Mueller-Hinton agar, and disk diffusion using Mueller-Hinton agar supplemented with 5% horse blood (MHF). To investigate the potential clinical relevance of SXT heteroresistance, an in vivo Galleria mellonella infection assay was performed. All Vitek 2 SXT-susceptible (n = 17) isolates were concordant with AST results by other methods applied in this study. In 32/78 (41%) of Vitek 2 SXT-resistant isolates, we observed a heteroresistant growth phenotype on MHF. The heteroresistance phenotype was associated with the presence of dfr genes, encoding trimethoprim resistance. The addition of a hemin-impregnated disk in a double disk diffusion method on standard Mueller-Hinton agar was able to induce growth in the SXT zone of inhibition. An in vivo infection assay with G. mellonella suggested that the SXT heteroresistance phenotype resulted in lethality similar to that of the SXT-resistant phenotype. In this study, we describe a novel hemin-inducible heteroresistance phenotype in S. aureus. This heteroresistance phenotype may be missed by standard AST methods but can be detected by performing disk diffusion using Mueller-Hinton agar supplemented with 5% horse blood, commonly used for AST of fastidious organisms. This phenomenon may partly explain the discrepancies of AST methods in determining SXT resistance in S. aureus. IMPORTANCE Staphylococcus aureus is one of most important pathogens in clinical medicine. Besides its virulence, the acquisition or emergence of resistance toward antibiotic agents, in particular to beta-lactam antibiotics (methicillin-resistant S. aureus [MRSA]), poses a major therapeutic challenge. Trimethoprim-sulfamethoxazole (SXT) is one of the effective antimicrobial agents of last resort to treat MRSA infections. Here, we report the detection of a SXT-heteroresistant phenotype which is inducible by hemin and can be detected using Mueller-Hinton agar supplemented with horse blood. Heteroresistance describes the presence or emergence of resistant subpopulations, which may potentially lead to inaccurate antibiotic susceptibility testing results and influence the success of antibiotic therapy.
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Affiliation(s)
- Dennis Nurjadi
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Quan Chanthalangsy
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Elfi Zizmann
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Vanessa Stuermer
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Maximilian Moll
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Sabrina Klein
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Sébastien Boutin
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Klaus Heeg
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Philipp Zanger
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
- Heidelberg Institute of Global Health, Heidelberg University Hospital, Heidelberg, Germany
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17
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Emergence of Thymidine-Dependent Staphylococcus aureus Small-Colony Variants in Cystic Fibrosis Patients in Southern Brazil. Microbiol Spectr 2021; 9:e0061421. [PMID: 34319160 PMCID: PMC8552798 DOI: 10.1128/spectrum.00614-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized Staphylococcus aureus small-colony variant (SCV) strains isolated from cystic fibrosis (CF) patients in southern Brazil. Smaller colonies of S. aureus were isolated from respiratory samples collected consecutively from 225 CF patients from July 2013 to November 2016. Two phenotypic methods—the auxotrophic classification and a modified method of antimicrobial susceptibility testing—were employed. PCR was conducted to detect the mecA, ermA, ermB, ermC, msrA, and msrB resistance genes. Furthermore, DNA sequencing was performed to determine the mutations in the thyA gene, and multilocus sequence typing was used to identify the genetic relatedness. S. aureus strains were isolated from 186 patients (82%); suggestive colonies of SCVs were obtained in 16 patients (8.6%). The clones CC1 (ST1, ST188, and ST2383), CC5 (ST5 and ST221), and ST398 were identified. Among SCVs, antimicrobial susceptibility testing showed that 77.7% of the isolates were resistant to multiple drugs, and all of them were susceptible to vancomycin. mecA (2), ermA (1), ermB (1), ermC (3), and msrB (18) were distributed among the isolates. Phenotypically thymidine-dependent isolates had different mutations in the thyA gene, and frameshift mutations were frequently observed. Of note, revertants showed nonconservative or conservative missense mutations. SCVs are rarely identified in routine laboratory tests. IMPORTANCE Similar findings have not yet been reported in Brazil, emphasizing the importance of monitoring small-colony variants (SCVs). Altogether, our results highlight the need to improve detection methods and review antimicrobial therapy protocols in cystic fibrosis (CF) patients.
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18
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Antistaphylococcal Activity of the FtsZ Inhibitor C109. Pathogens 2021; 10:pathogens10070886. [PMID: 34358036 PMCID: PMC8308607 DOI: 10.3390/pathogens10070886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/08/2021] [Accepted: 07/10/2021] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus infections represent a great concern due to their versatility and involvement in different types of diseases. The shortage of available clinical options, especially to treat multiresistant strains, makes the discovery of new effective compounds essential. Here we describe the activity of the previously described cell division inhibitor C109 against methicillin-sensitive and -resistant S. aureus strains. Antibiofilm activity was assessed using microtiter plates, confocal microscopy, and in an in vitro biofilm wound model. The ability of C109 to block FtsZ GTPase activity and polymerization was tested in vitro. Altogether, the results show that the FtsZ inhibitor C109 has activity against a wide range of S. aureus strains and support its use as an antistaphylococcal compound.
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19
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Saliu F, Rizzo G, Bragonzi A, Cariani L, Cirillo DM, Colombo C, Daccò V, Girelli D, Rizzetto S, Sipione B, Cigana C, Lorè NI. Chronic infection by nontypeable Haemophilus influenzae fuels airway inflammation. ERJ Open Res 2021; 7:00614-2020. [PMID: 33778054 PMCID: PMC7983230 DOI: 10.1183/23120541.00614-2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/06/2020] [Indexed: 12/14/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is commonly isolated from airways of patients suffering from chronic respiratory diseases, such as COPD or cystic fibrosis (CF). However, to what extent NTHi long-term infection contributes to the lung inflammatory burden during chronic airway disease is still controversial. Here, we exploited human respiratory samples from a small cohort of CF patients and found that patients chronically infected with NTHi had significantly higher levels of interleukin (IL)-8 and CXCL1 than those who were not infected. To better define the impact of chronic NTHi infection in fuelling inflammatory response in chronic lung diseases, we developed a new mouse model using both laboratory and clinical strains. Chronic NTHi infection was associated with chronic inflammation of the lung, characterised by recruitment of neutrophils and cytokine release keratinocyte-derived chemokine (KC), macrophage inflammatory protein 2 (MIP-2), granulocyte colony-stimulating factor (G-CFS), IL-6, IL-17A and IL-17F) at 2 and 14 days post-infection. An increased burden of T-cell-mediated response (CD4+ and γδ cells) and higher levels of pro-matrix metalloproteinase 9 (pro-MMP9), known to be associated with tissue remodelling, were observed at 14 days post-infection. Of note we found that both CD4+IL-17+ cells and levels of IL-17 cytokines were enriched in mice at advanced stages of NTHi chronic infection. Moreover, by immunohistochemistry we found CD3+, B220+ and CXCL-13+ cells localised in bronchus-associated lymphoid tissue-like structures at day 14. Our results demonstrate that chronic NTHi infection exerts a pro-inflammatory activity in the human and murine lung and could therefore contribute to the exaggerated burden of lung inflammation in patients at risk. The pathological impact of long-term infection by nontypeable Haemophilus influenzae (NTHi) is still debated. Chronic NTHi infection fuels lung inflammation in human samples and in a new mouse model of bacterial long-term persistence.https://bit.ly/3lvyvge
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Affiliation(s)
- Fabio Saliu
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Emerging bacterial pathogens Unit, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy.,IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
| | - Giulia Rizzo
- Università Vita-Salute San Raffaele, Milan, Italy.,IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
| | - Alessandra Bragonzi
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
| | - Lisa Cariani
- Cystic Fibrosis Microbiology Laboratory, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - Daniela M Cirillo
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Emerging bacterial pathogens Unit, Milan, Italy
| | - Carla Colombo
- Cystic Fibrosis Regional Reference Center, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Valeria Daccò
- Cystic Fibrosis Regional Reference Center, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Daniela Girelli
- Cystic Fibrosis Microbiology Laboratory, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - Sara Rizzetto
- Cystic Fibrosis Microbiology Laboratory, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - Barbara Sipione
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
| | - Cristina Cigana
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
| | - Nicola I Lorè
- IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Emerging bacterial pathogens Unit, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy.,IRCCS San Raffaele Scientific Institute, Division of Immunology, Transplantation, and Infectious Diseases, Infections and cystic fibrosis unit, Milan, Italy
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20
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Camus L, Briaud P, Vandenesch F, Moreau K. How Bacterial Adaptation to Cystic Fibrosis Environment Shapes Interactions Between Pseudomonas aeruginosa and Staphylococcus aureus. Front Microbiol 2021; 12:617784. [PMID: 33746915 PMCID: PMC7966511 DOI: 10.3389/fmicb.2021.617784] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/10/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus are the two most prevalent bacteria species in the lungs of cystic fibrosis (CF) patients and are associated with poor clinical outcomes. Co-infection by the two species is a frequent situation that promotes their interaction. The ability of P. aeruginosa to outperform S. aureus has been widely described, and this competitive interaction was, for a long time, the only one considered. More recently, several studies have described that the two species are able to coexist. This change in relationship is linked to the evolution of bacterial strains in the lungs. This review attempts to decipher how bacterial adaptation to the CF environment can induce a change in the type of interaction and promote coexisting interaction between P. aeruginosa and S. aureus. The impact of coexistence on the establishment and maintenance of a chronic infection will also be presented, by considering the latest research on the subject.
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Affiliation(s)
- Laura Camus
- CIRI-Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR 5308/ENS de Lyon, Lyon, France
| | - Paul Briaud
- CIRI-Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR 5308/ENS de Lyon, Lyon, France
| | - François Vandenesch
- CIRI-Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR 5308/ENS de Lyon, Lyon, France.,Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Lyon, France.,Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Karen Moreau
- CIRI-Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR 5308/ENS de Lyon, Lyon, France
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Tan X, Coureuil M, Ramond E, Euphrasie D, Dupuis M, Tros F, Meyer J, Nemazanyy I, Chhuon C, Guerrera IC, Ferroni A, Sermet-Gaudelus I, Nassif X, Charbit A, Jamet A. Chronic Staphylococcus aureus Lung Infection Correlates With Proteogenomic and Metabolic Adaptations Leading to an Increased Intracellular Persistence. Clin Infect Dis 2020; 69:1937-1945. [PMID: 30753350 DOI: 10.1093/cid/ciz106] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 01/31/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Chronic lung infection in cystic fibrosis (CF) patients by Staphylococcus aureus is a well-established epidemiological fact. Indeed, S. aureus is the most commonly identified pathogen in the lungs of CF patients. Improving our understanding of the mechanisms associated with the persistence of S. aureus is therefore an important issue. METHODS We selected pairs of sequential S. aureus isolates from 3 patients with CF and from 1 patient with non-CF chronic lung disease. We used a combination of genomic, proteomic, and metabolomic approaches with functional assays for in-depth characterization of S. aureus long-term persistence. RESULTS In this study, we show that late S. aureus isolates from CF patients have an increased ability for intracellular survival in CF bronchial epithelial-F508del cells compared to ancestral early isolates. Importantly, the increased ability to persist intracellularly was confirmed for S. aureus isolates within the own-patient F508del epithelial cells. An increased ability to form biofilm was also demonstrated. Furthermore, we identified the underlying genetic modifications that induce altered protein expression profiles and notable metabolic changes. These modifications affect several metabolic pathways and virulence regulators that could constitute therapeutic targets. CONCLUSIONS Our results strongly suggest that the intracellular environment might constitute an important niche of persistence and relapse necessitating adapted antibiotic treatments.
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Affiliation(s)
- Xin Tan
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Mathieu Coureuil
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Elodie Ramond
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Daniel Euphrasie
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Marion Dupuis
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Fabiola Tros
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Julie Meyer
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Ivan Nemazanyy
- Plateforme d'étude du métabolisme, Structure Fédérative de Recherche INSERM US24/CNRS UMS3633, Paris, France
| | - Cerina Chhuon
- Plateforme Protéome Institut Necker-Enfants Malades, PPN, Structure Fédérative de Recherche SFR Necker, University Paris Descartes, Paris, France
| | - Ida Chiara Guerrera
- Proteomics platform 3P5-Necker, Université Paris Descartes - Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Paris, France
| | - Agnes Ferroni
- Laboratoire de Microbiologie de l'hopital Necker, University Paris Descartes, Paris, France
| | - Isabelle Sermet-Gaudelus
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Canalopathies épithéliales: la mucoviscidose et autres maladies, Paris, France
| | - Xavier Nassif
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Alain Charbit
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
| | - Anne Jamet
- Université Paris Descartes, INSERM U1151 - CNRS UMR 8253, Institut Necker-Enfants Malades. Team: Pathogenesis of Systemic Infections, Paris, France
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Antonello RM, Principe L, Maraolo AE, Viaggi V, Pol R, Fabbiani M, Montagnani F, Lovecchio A, Luzzati R, Di Bella S. Fosfomycin as Partner Drug for Systemic Infection Management. A Systematic Review of Its Synergistic Properties from In Vitro and In Vivo Studies. Antibiotics (Basel) 2020; 9:antibiotics9080500. [PMID: 32785114 PMCID: PMC7460049 DOI: 10.3390/antibiotics9080500] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/01/2020] [Accepted: 08/03/2020] [Indexed: 12/31/2022] Open
Abstract
Fosfomycin is being increasingly prescribed for multidrug-resistant bacterial infections. In patients with systemic involvement, intravenous fosfomycin is usually administered as a partner drug, as part of an antibiotic regimen. Hence, the knowledge of fosfomycin pharmacodynamic interactions (synergistic, additive, indifferent and antagonistic effect) is fundamental for a proper clinical management of severe bacterial infections. We performed a systematic review to point out fosfomycin’s synergistic properties, when administered with other antibiotics, in order to help clinicians to maximize drug efficacy optimizing its use in clinical practice. Interactions were more frequently additive or indifferent (65.4%). Synergism accounted for 33.7% of total interactions, while antagonism occurred sporadically (0.9%). Clinically significant synergistic interactions were mostly distributed in combination with penicillins (51%), carbapenems (43%), chloramphenicol (39%) and cephalosporins (33%) in Enterobactaerales; with linezolid (74%), tetracyclines (72%) and daptomycin (56%) in Staphylococcus aureus; with chloramphenicol (53%), aminoglycosides (43%) and cephalosporins (36%) against Pseudomonas aeruginosa; with daptomycin (97%) in Enterococcus spp. and with sulbactam (75%) and penicillins (60%) and in Acinetobacter spp. fosfomycin-based antibiotic associations benefit from increase in the bactericidal effect and prevention of antimicrobial resistances. Taken together, the presence of synergistic interactions and the nearly total absence of antagonisms, make fosfomycin a good partner drug in clinical practice.
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Affiliation(s)
- Roberta Maria Antonello
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, 34127 Trieste, Italy; (R.M.A.); (A.L.); (R.L.)
| | | | - Alberto Enrico Maraolo
- First Division of Infectious Diseases, Cotugno Hospital, AORN dei Colli, 80131 Naples, Italy;
| | | | - Riccardo Pol
- Department of Infectious Diseases, Udine University, 33100 Udine, Italy;
| | - Massimiliano Fabbiani
- Department of Medical Sciences, Tropical and Infectious Diseases Unit, University Hospital of Siena, 53100 Siena, Italy; (M.F.); (F.M.)
| | - Francesca Montagnani
- Department of Medical Sciences, Tropical and Infectious Diseases Unit, University Hospital of Siena, 53100 Siena, Italy; (M.F.); (F.M.)
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Antonio Lovecchio
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, 34127 Trieste, Italy; (R.M.A.); (A.L.); (R.L.)
| | - Roberto Luzzati
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, 34127 Trieste, Italy; (R.M.A.); (A.L.); (R.L.)
| | - Stefano Di Bella
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, 34127 Trieste, Italy; (R.M.A.); (A.L.); (R.L.)
- Correspondence:
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23
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Oe C, Hayashi H, Hirata K, Kawaji K, Hashima F, Sasano M, Furuichi M, Usui E, Katsumi M, Suzuki Y, Nakajima C, Kaku M, Kodama EN. Pyrimidine Analogues as a New Class of Gram-Positive Antibiotics, Mainly Targeting Thymineless-Death Related Proteins. ACS Infect Dis 2020; 6:1490-1500. [PMID: 31540548 DOI: 10.1021/acsinfecdis.9b00305] [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] [Indexed: 12/16/2022]
Abstract
Multidrug-resistant (MDR) bacteria are widespread throughout the world and pose an increasingly serious threat to human and animal health. Besides implementing strict measures to prevent improper antibiotic use, it remains essential that novel antibiotics must be developed. These antibiotics need to exert their activity via mechanisms different from those employed by currently approved antibiotics. In this study, we used several 5-fluorouracil (5-FU) analogues as chemical probes and investigated the potential of these pyrimidine analogues as antibacterial agents. Several 5-FU derivatives exerted potent activity against strains of Gram-positive cocci (GPC) that are susceptible or resistant toward approved antibiotics, without showing cross-resistance. Furthermore, we have provided evidence that the pyrimidine analogues exerted anti-GPC activity via thymineless death by inhibition of thymidylate synthetase (ThyA) and/or inhibition of RNA synthesis. Interestingly, whole genome resequencing of in vitro-selected, pyrimidine analogue-resistant Staphylococcus aureus mutants indicated that S. aureus strains with pyrimidine-analogue resistance induced an amino acid (AA) substitution, deletion, and/or insertion into thymineless-death related proteins except for ThyA, or enhanced the ThyA transcription level. Thus, S. aureus may avoid altering the ThyA function by introducing an AA substitution, suggesting that the pyrimidine analogues, which directly bind to ThyA without phosphorylation, may be more effective and show a higher genetic barrier than the pyrimidines that depend on phosphorylation for activity. The findings of this study may assist in the future development of a novel class of antibiotics for combating MDR GPC, including methicillin-resistant S. aureus and vancomycin-resistant Enterococci.
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Affiliation(s)
- Chihiro Oe
- Department of Infection Control and Laboratory Diagnostics, Internal Medicine, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Hironori Hayashi
- Department of Clinical Laboratory Medicine, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan
- Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Kazushige Hirata
- Department of Clinical Laboratory Medicine, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan
| | - Kumi Kawaji
- Department of Infectious Diseases, International Research Institute of Disaster Science, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Fusako Hashima
- Department of Clinical Laboratory Medicine, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan
| | - Mina Sasano
- Department of Infectious Diseases, International Research Institute of Disaster Science, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Maaya Furuichi
- Department of Infectious Diseases, International Research Institute of Disaster Science, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Emiko Usui
- Department of Infectious Diseases, International Research Institute of Disaster Science, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Makoto Katsumi
- Department of Clinical Laboratory Medicine, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan
| | - Yasuhiko Suzuki
- Division of Bioresources, Hokkaido University Research Centre for Zoonosis Control, North 20, West 10 Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Chie Nakajima
- Division of Bioresources, Hokkaido University Research Centre for Zoonosis Control, North 20, West 10 Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Mitsuo Kaku
- Department of Infection Control and Laboratory Diagnostics, Internal Medicine, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
- Department of Clinical Laboratory Medicine, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan
- Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Eiichi N. Kodama
- Department of Infectious Diseases, International Research Institute of Disaster Science, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
- Department of Infectious Diseases, Graduate School of Medicine and Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
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24
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de Souza DC, Cogo LL, Palmeiro JK, Dalla-Costa LM, de Oliveira Tomaz AP, Riedi CA, Rosario Filho NA. Thymidine-auxotrophic Staphylococcus aureus small-colony variant bacteremia in a patient with cystic fibrosis. Pediatr Pulmonol 2020; 55:1388-1393. [PMID: 32176841 DOI: 10.1002/ppul.24730] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/05/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Small-colony variants (SCVs) are a morphologic subtype of Staphylococcus aureus that may occur through several mechanisms including auxotrophism for thymidine, hemin, or menadione. Auxotrophic SCV for thymidine fail to synthesize DNA specifically because of mutations in the thymidylate synthase gene. We isolated S. aureus thymidine-dependent SCVs (TD-SCV) from blood and respiratory samples of a pediatric patient with cystic fibrosis and pulmonary exacerbation. METHODS Nutritional dependence of SCVs on hemin, menadione, and thymidine was evaluated. Antimicrobial susceptibility testing was performed through broth microdilution. Polymerase chain reaction was carried out for mecA, ermA, ermB, ermC, msrA, and msrB resistance genes. DNA sequencing was used to determine mutations in thyA and the multilocus sequence typing to identify genetic relatedness. RESULTS Methicillin-sensitive S. aureus with normal and TD-SCV phenotypes were isolated from respiratory samples and a TD-SCV phenotype was isolated from blood culture. Macrolides resistance was attributed to ermC and msrB genes. All isolates belonged to ST398. The thyA gene in S. aureus is 957 nucleotides in length and encodes a protein of 318 amino acids. The TD-SCV isolates carried a -2 nt frameshift mutation (delta 667GC668) in thyA, creating a stop codon at residue 222 close to the predicted binding site for deoxyuridine monophosphate. CONCLUSIONS The pathogenesis of SCVs is complex and not fully elucidated. Factors inherent to the patient such as physiological conditions, recurrent infections, or coinfection should be considered. Although SCVs are considered less virulent, they showed the ability to invade and cause bacteremia in the patient.
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Affiliation(s)
- Dilair C de Souza
- Laboratório de Bacteriologia, Complexo Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil
| | - Laura L Cogo
- Laboratório de Bacteriologia, Complexo Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil
| | - Jussara K Palmeiro
- Programa de Pós-graduação em Biotecnologia e saúde da Criança e do Adolescente, Faculdades e Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Departamento de Análises Clínicas, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Libera M Dalla-Costa
- Programa de Pós-graduação em Biotecnologia e saúde da Criança e do Adolescente, Faculdades e Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil
| | - Ana P de Oliveira Tomaz
- Laboratório de Bacteriologia, Complexo Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil.,Programa de Pós-graduação em Biotecnologia e saúde da Criança e do Adolescente, Faculdades e Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil
| | - Carlos A Riedi
- Departamento de Pediatria, Complexo Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil
| | - Nelson A Rosario Filho
- Departamento de Pediatria, Complexo Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil
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25
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Abstract
Cystic fibrosis (CF) is a genetic, multisystem disease due to defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, an anion channel responsible for chloride and bicarbonate trafficking. Although this channel is expressed in many tissues, its impaired function in airway epithelial cells leads to hyperviscous mucous secretions impeding effective mucociliary clearance. Impaired clearance of inhaled microorganisms results in the establishment of chronic infection, triggering an overexaggerated inflammatory response. The resulting release of inflammatory cytokines and enzymes causes pulmonary damage in the form of bronchiectasis, further impairing mucociliary action, forming a vicious cycle. Subsequent respiratory failure remains the leading cause of death in individuals with CF.
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Affiliation(s)
- Stephanie Duggins Davis
- The University of North Carolina at Chapel Hill, Department of Pediatrics, UNC Children’s Hospital, Chapel Hill, NC USA
| | - Margaret Rosenfeld
- Department of Pediatrics, University of Washington School of Medicine, Division of Pulmonary and Sleep Medicine Seattle Children’s Hospital, Seattle, WA USA
| | - James Chmiel
- Department of Pediatrics, Indiana University School of Medicine, Division of Pediatric Pulmonology, Allergy and Sleep Medicine, Riley Hospital for Children at IU Health, Indianapolis, IN USA
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26
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Wolter DJ, Onchiri FM, Emerson J, Precit MR, Lee M, McNamara S, Nay L, Blackledge M, Uluer A, Orenstein DM, Mann M, Hoover W, Gibson RL, Burns JL, Hoffman LR. Prevalence and clinical associations of Staphylococcus aureus small-colony variant respiratory infection in children with cystic fibrosis (SCVSA): a multicentre, observational study. THE LANCET RESPIRATORY MEDICINE 2019; 7:1027-1038. [PMID: 31727592 DOI: 10.1016/s2213-2600(19)30365-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/08/2019] [Accepted: 09/05/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Staphylococcus aureus is the bacterium cultured most often from respiratory secretions of people with cystic fibrosis. Both meticillin-susceptible S aureus and meticillin-resistant S aureus (MRSA) can adapt to form slow-growing, antibiotic-resistant isolates known as small-colony variants that are not routinely identified by clinical laboratories. We aimed to determine the prevalence and clinical significance of S aureus small-colony variants and their subtypes among children with cystic fibrosis. METHODS The Small Colony Variant Staphylococcus aureus (SCVSA) study was a 2-year longitudinal study of children aged 6-16 years at five US cystic fibrosis centres, using culture methods sensitive for small-colony variants. Children were eligible if they had a documented diagnosis of cystic fibrosis and a minimum of two cystic fibrosis clinic visits and two respiratory cultures in the previous 12 months at enrolment. Participants attended clinic visits quarterly, at which respiratory tract samples were taken and measures of lung function (percentage of predicted forced expiratory volume in 1 s [FEV1] and frequency of respiratory exacerbations) were recorded. We determined the prevalence of small-colony variants and their subtypes, and assessed their independent associations with lung function and respiratory exacerbations using linear mixed-effects and generalised estimating equation logistic regression models. Analyses included both univariate models (unadjusted) and multivariate models that adjusted for potential confounders, including age, sex, race, baseline microbiology, treatment with CFTR modulator, and CTFR genotype. FINDINGS Between July 1, 2014, and May 26, 2015, we enrolled 230 children. Participants were followed-up for 2 years, with a mean of 6·4 visits (SD 1·14) per participant (range 2-9 visits) and a mean interval between visits of 3·94 months (SD 1·77). Across the 2-year period, S aureus small-colony variants were detected in 64 (28%) participants. Most (103 [56%] of 185) of the small-colony variants detected in these participants were thymidine dependent. Children with small-colony variants had significantly lower mean percentage of predicted FEV1 at baseline than did children without small-colony variants (85·5 [SD 19] vs 92·4 [SD 18·6]; p=0·0145). Small-colony variants were associated with significantly lower percentage of predicted FEV1 throughout the study in regression models, both in univariate analyses (regression coefficient -7·07, 95% CI -12·20 to -1·95; p=0·0068) and in multivariate analyses adjusting for potential confounders (-5·50, -10·51 to -0·48; p=0·0316). Small colony variants of the thymidine-dependent subtype had the strongest association with lung function in multivariate regression models (regression coefficient -10·49, -17·25 to -3·73; p=0·0024). Compared with children without small-colony variants, those with small-colony variants had significantly increased odds of respiratory exacerbations in univariate analyses (odds ratio 1·73, 95% CI 1·19 to 2·52; p=0·0045). Children with thymidine-dependent small-colony variants had significantly increased odds of respiratory exacerbations (2·81, 1·69-4·67; p=0·0001), even after adjusting for age, sex, race, genotype, CFTR modulator, P aeruginosa culture status, and baseline percentage of predicted FEV1 (2·17, 1·33-3·57; p=0·0021), whereas those with non-thymidine-dependent small-colony variants did not. In multivariate models including small-colony variants and MRSA status, P aeruginosa was not independently associated with lung function (regression coefficient -4·77, 95% CI -10·36 to 0·83; p=0·10) and was associated with reduced odds of exacerbations (0·54, 0·36 to 0·81; p=0·0028). Only the small-colony variant form of MRSA was associated with reduced lung function (-8·44, -16·15 to -0·72; p=0·0318) and increased odds of exacerbations (2·15, 1·24 to 3·71; p=0·0061). INTERPRETATION Infection with small-colony variants, and particularly thymidine-dependent small-colony variants, was common in a multicentre paediatric population with cystic fibrosis and associated with reduced lung function and increased risk of respiratory exacerbations. The adoption of small-colony variant identification and subtyping methods by clinical laboratories, and the inclusion of small-colony variant prevalence data in cystic fibrosis registries, should be considered for ongoing surveillance and study. FUNDING The Cystic Fibrosis Foundation and the National Institutes of Health.
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Affiliation(s)
- Daniel J Wolter
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | | | - Julia Emerson
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Mimi R Precit
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Michael Lee
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Sharon McNamara
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Laura Nay
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | | | - Ahmet Uluer
- Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Brigham and Women's Hospital, Boston, MA, USA
| | - David M Orenstein
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michelle Mann
- Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Wynton Hoover
- Department of Pediatrics, University of Alabama, Tuscaloosa, AL, USA
| | - Ronald L Gibson
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Jane L Burns
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Lucas R Hoffman
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA.
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27
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Rakovskaya IV, Ermolaeva SA, Levina GA, Barkhatova OI, Mukhachev AY, Andreevskaya SG, Zhukhovitsky VG, Gorina LG, Miller GG, Sysolyatina EV. Microcolonies: a novel morphological form of pathogenic Mycoplasma spp. J Med Microbiol 2019; 68:1747-1758. [PMID: 31671056 DOI: 10.1099/jmm.0.001081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Introduction. The Mollicutes class unites cell wall lacking bacteria many of which are membrane parasites and opportunistic bacteria.Aim. This study describes a novel morphological form found in the five species belonging to the bacterial class Mollicutes, and referred to as microcolonies (MCs).Methodology. MCs were obtained as described below and characterized with bacteriological and immunological methods, and microscopy.Results. In contrast to typical colonies (TCs), MCs are characterized by tiny propeller-shaped colonies formed by rod-like cells tightly packed in parallel rows. These colonies were observed within routinely cultivated cultures of type strains 7-12 days post-plating. Rod-like cells were visualized using a scanning electron microscope within TCs with a 'fried-egg-like' appearance. MCs were not observed to revert to TCs. MCs were resistant to antibiotics and other treatments effective against TCs. Pure MC cultures were generated in vitro by treatment of Mycoplasma cultures with hyperimmune serum, antibiotics or argon non-thermal plasma. MCs of Mycoplasma hominis strain H-34 were characterized in detail to confirm that they belonged to that species. MCs tested positive via PCR with M. hominis-specific primers, direct fluorescence and epifluorescence tests, and Western blotting with the camel-derived nanobody aMh-FcG2a, which is specific to the MH3620 transporter protein. Meanwhile, MCs behaved differently in standard bacteriological tests. Pure MC cultures were also isolated directly from clinical samples of the serum, synovial liquid and urine of patients within flammatory urogenital tract diseases, asthma or arthritis. In total, 79 independent MC cultures were isolated from clinical samples including M. hominis (n=70), Mycoplasma pneumoniae (n=2), Mycoplasma fermentans (n=2) and Mycoplasma spp. (n=5).Conclusion. MCs play an unknown role in infection pathology and display prominent antibiotic resistance, making them a challenge for the future studies on Mollicutes.
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Affiliation(s)
- Irina V Rakovskaya
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Svetlana A Ermolaeva
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Galina A Levina
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Olga I Barkhatova
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Andrey Ya Mukhachev
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | | | | | - Luisa G Gorina
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Galina G Miller
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Elena V Sysolyatina
- Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia
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28
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MpsAB is important for Staphylococcus aureus virulence and growth at atmospheric CO 2 levels. Nat Commun 2019; 10:3627. [PMID: 31399577 PMCID: PMC6689103 DOI: 10.1038/s41467-019-11547-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 07/16/2019] [Indexed: 01/06/2023] Open
Abstract
The mechanisms behind carbon dioxide (CO2) dependency in non-autotrophic bacterial isolates are unclear. Here we show that the Staphylococcus aureus mpsAB operon, known to play a role in membrane potential generation, is crucial for growth at atmospheric CO2 levels. The genes mpsAB can complement an Escherichia coli carbonic anhydrase (CA) mutant, and CA from E. coli can complement the S. aureus delta-mpsABC mutant. In comparison with the wild type, S. aureus mps mutants produce less hemolytic toxin and are less virulent in animal models of infection. Homologs of mpsA and mpsB are widespread among bacteria and are often found adjacent to each other on the genome. We propose that MpsAB represents a dissolved inorganic carbon transporter, or bicarbonate concentrating system, possibly acting as a sodium bicarbonate cotransporter.
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Watanabe Y, Oikawa N, Hariu M, Seki M. Evaluation of agar culture plates to efficiently identify small colony variants of methicillin-resistant Staphylococcus aureus. Infect Drug Resist 2019; 12:1743-1748. [PMID: 31417291 PMCID: PMC6593740 DOI: 10.2147/idr.s207057] [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: 02/27/2019] [Accepted: 05/22/2019] [Indexed: 11/23/2022] Open
Abstract
Background: Small-colony variants of methicillin-resistant Staphylococcus aureus (SCV-MRSA) recently were described as slow-growing, thymidine-dependent strains; typically, SCV-MRSA were isolated from patients receiving sulfamethoxazole-trimethoprim, but detection of these strains frequently was delayed because of their small colony size and slow growth. Bacteremia cases due to SCV-MRSA sometimes become lethal when the initiation of treatment with intravenous anti-methicillin-resistant Staphylococcus aureus (MRSA) drugs starts too late. Methods: Here, we evaluated the use of general MRSA-specific agar plates in Japan, including MS-CFX, X-MRSA, and CHROMagar, for the efficient detection of SCV-MRSA, including the comparative detection efficiencies of these media for stock strains and clinical isolates. Results: Among the three MRSA-specific agar plates that were tested, X-MRSA and CHROMagar showed similar detection efficiencies for both 24 and 48 hrs culturing; in contrast, MS-CFS did not permit the detection of SCV-MRSA in stock strains. For clinical isolates of SCV-MRSA, X-MRSA plates permitted detection of the smallest and slowest-growing colonies of SCV-MRSA at 48 hrs of culturing; in contrast, CHROMagar and MS-CFX sometimes did not identify SCV-MRSA at 24 and 48 hrs. Conclusion: Optimization of media and incubation times will be necessary for efficient identification for SCV-MRSA, which would prevent delays in diagnosis and treatment with anti-MRSA drugs.
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Affiliation(s)
- Yuji Watanabe
- Division of Infectious Diseases and Infection Control.,Laboratory for Clinical Microbiology, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan
| | - Nozomi Oikawa
- Division of Infectious Diseases and Infection Control.,Laboratory for Clinical Microbiology, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan
| | - Maya Hariu
- Division of Infectious Diseases and Infection Control.,Laboratory for Clinical Microbiology, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan
| | - Masafumi Seki
- Division of Infectious Diseases and Infection Control
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Kittinger C, Toplitsch D, Folli B, Masoud Landgraf L, Zarfel G. Phenotypic Stability of Staphylococcus Aureus Small Colony Variants (SCV) Isolates from Cystic Fibrosis (CF) Patients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16111940. [PMID: 31159295 PMCID: PMC6603916 DOI: 10.3390/ijerph16111940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/28/2019] [Accepted: 05/30/2019] [Indexed: 12/23/2022]
Abstract
One of the most interesting features of Staphylococcus aureus is its ability to switch to a small colony variant (SCV). This switch allows the pathogen to survive periods of antibiotic treatment or pressure from the immune system of the host and further enables it to start the infection once again after the environmental stress declines. However, so far only little is known about this reversion back to the more virulent wild type phenotype. Therefore, this study aimed to analyze the frequency of reversion to the wild type phenotype of thymidine auxotroph S. aureus SCV isolates (TD-SCVs) obtained from patients with cystic fibrosis (CF). With the use of single cell starting cultures, the occurrence of the thymidine prototroph revertants was monitored. The underlying mutational cause of the SCVs and subsequent revertants were analyzed by sequencing the gene coding for thymidylate synthase (ThyA), whose mutations are known to produce thymidine auxotroph S. aureus SCV. In our study, the underlying mutational cause for the switch to the TD-SCV phenotype was primarily point mutations. Out of twelve isolates, seven isolates showed an occurrence of revertants with a frequency ranging from 90.06% to 0.16%. This high variability in the frequency of reversion to the wild type was not expected. However, this variability in the frequency of reversion may also be the key to successful re-infection of the host. Sometimes quick reversion to the wild type proves necessary for survival, whereas other times, staying hidden for a bit longer leads to success in re-colonization of the host.
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Affiliation(s)
- Clemens Kittinger
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Daniela Toplitsch
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Bettina Folli
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Lilian Masoud Landgraf
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Gernot Zarfel
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
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Dezube R, Jennings MT, Rykiel M, Diener-West M, Boyle MP, Chmiel JF, Dasenbrook EC. Eradication of persistent methicillin-resistant Staphylococcus aureus infection in cystic fibrosis. J Cyst Fibros 2019; 18:357-363. [DOI: 10.1016/j.jcf.2018.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/20/2018] [Accepted: 07/20/2018] [Indexed: 01/09/2023]
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Abstract
Staphylococcus aureus is capable of becoming resistant to all classes of antibiotics clinically available and resistance can develop through de novo mutations in chromosomal genes or through acquisition of horizontally transferred resistance determinants. This review covers the most important antibiotics available for treatment of S. aureus infections and a special emphasis is dedicated to the current knowledge of the wide variety of resistance mechanisms that S. aureus employ to withstand antibiotics. Since resistance development has been inevitable for all currently available antibiotics, new therapies are continuously under development. Besides development of new small molecules affecting cell viability, alternative approaches including anti-virulence and bacteriophage therapeutics are being investigated and may become important tools to combat staphylococcal infections in the future.
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Schleimer N, Kaspar U, Knaack D, von Eiff C, Molinaro S, Grallert H, Idelevich EA, Becker K. In Vitro Activity of the Bacteriophage Endolysin HY-133 against Staphylococcus aureus Small-Colony Variants and Their Corresponding Wild Types. Int J Mol Sci 2019; 20:E716. [PMID: 30736446 PMCID: PMC6387228 DOI: 10.3390/ijms20030716] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 01/06/2023] Open
Abstract
Nasal carriage of methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) represents both a source and a risk factor for subsequent infections. However, existing MRSA decolonization strategies and antibiotic treatment options are hampered by the duration of administration and particularly by the emergence of resistance. Moreover, beyond classical resistance mechanisms, functional resistance as the formation of the small-colony variant (SCV) phenotype may also impair the course and treatment of S. aureus infections. For the recombinant bacteriophage endolysin HY-133, rapid bactericidal and highly selective in vitro activities against MSSA and MRSA has been shown. In order to assess the in vitro efficacy of HY-133 against the SCV phenotype, minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) were evaluated on clinical SCVs, their isogenic wild types, as well as on genetically derived and gentamicin-selected SCVs. For all strains and growth phases, HY-133 MIC and MBC ranged between 0.12 and 1 mg/L. Time-kill studies revealed a fast-acting bactericidal activity of HY-133 resulting in a ≥3 - log10 decrease in CFU/mL within 1 h compared to oxacillin, which required 4⁻24 h. Since the mode of action of HY-133 was independent of growth phase, resistance pattern, and phenotype, it is a promising candidate for future S. aureus decolonization strategies comprising rapid activity against phenotypic variants exhibiting functional resistance.
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Affiliation(s)
- Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
| | - Ursula Kaspar
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
| | - Dennis Knaack
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
| | | | | | - Evgeny A Idelevich
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster (UKM), 48149 Münster, Germany.
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Sato T, Kawamura M, Furukawa E, Fujimura S. Screening method for trimethoprim/sulfamethoxazole-resistant small colony variants of Staphylococcus aureus. J Glob Antimicrob Resist 2018; 15:1-5. [PMID: 29857058 DOI: 10.1016/j.jgar.2018.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/08/2018] [Accepted: 05/13/2018] [Indexed: 10/16/2022] Open
Abstract
OBJECTIVES Trimethoprim/sulfamethoxazole (SXT) is used to treat Staphylococcus aureus infections. However, the effect of treatment with SXT is sometimes not sufficient and there are patients whose treatment has to be prolonged. There are few reports of isolated strains of SXT-resistant S. aureus, but it is possible that some resistant strains cannot be detected by current testing methods We have therefore developed a tool to identify these resistant strains. METHODS The mutant selection window (MSW) of SXT for 40 clinical isolates of S. aureus, including 20 methicillin-resistant S. aureus (MRSA), was determined. The optimum concentration of SXT and thymidine in agar for detecting SXT-resistant small colony variants (SCVs) of S. aureus was investigated. RESULTS The MSW50 and MSW90 of SXT, presented as a multiple of the minimum inhibitory concentration (MIC), were 16× MIC and >256× MIC, respectively. SCVs were detected within the MSW in 32 (80%) of the 40 clinical isolates studied. To maintain the morphology of SCVs, the most suitable concentrations of SXT and thymidine for screening were 4mg/L and 0.01μg/mL, respectively. All 32 SCVs were resistant to SXT (MIC >32mg/L). The sensitivity and specificity of this screening method was 100% and 88.9%, respectively. CONCLUSIONS SXT-resistant SCVs are not usually detected by routine laboratory tests performed in hospitals. However, the screening test described here can easily distinguish SXT-resistant SCVs among S. aureus isolated from specimens. This newly developed screening test could become an important tool to prevent inappropriate use of SXT.
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Affiliation(s)
- Takumi Sato
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi Prefecture 981-8558, Japan
| | - Masato Kawamura
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi Prefecture 981-8558, Japan
| | - Emiko Furukawa
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi Prefecture 981-8558, Japan
| | - Shigeru Fujimura
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi Prefecture 981-8558, Japan.
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Schwerdt M, Neumann C, Schwartbeck B, Kampmeier S, Herzog S, Görlich D, Dübbers A, Große-Onnebrink J, Kessler C, Küster P, Schültingkemper H, Treffon J, Peters G, Kahl BC. Staphylococcus aureus in the airways of cystic fibrosis patients - A retrospective long-term study. Int J Med Microbiol 2018; 308:631-639. [PMID: 29501453 DOI: 10.1016/j.ijmm.2018.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 02/13/2018] [Accepted: 02/20/2018] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Cystic fibrosis (CF) is an autosomal recessive disease associated with chronic airway infections by Staphylococcus aureus as one of the earliest and most prevalent pathogens. We conducted a retrospective study to determine the S. aureus infection status of CF patients treated since 1994 at two certified CF-centres in Münster, Germany, to get insights into the dynamics of S. aureus airway infection and the clinical impact on lung function on a long-term perspective. MATERIALS AND METHODS We used data from our microbiological database collected between 1994 and 2016 for patients treated at two centres in Münster, Germany, respectively, to determine the infection status for S. aureus. Furthermore, the resistance to selected antibiotics was determined for all patients' isolates and for 15 patients on a longitudinal basis. In addition, the prevalence of adaptive phenotypes such as small colony variants (SCVs) and mucoid S. aureus was assessed. RESULTS For this study, 2867 patient years with respiratory specimens (mean of 9.3 years for every patient, range 1-22 years) were evaluated for 283 CF patients (median age of 7 years at the beginning of the observation period, range 0-57 years, 51% male). 18% of patients were rarely infected by S. aureus (≤24% of observation years), 20% of patients intermittently (25-49%) and 61% persistently (≥50% of observation period). Susceptibility testing for 12969 S. aureus isolates resulted in resistance to methicillin in 9%, trimethoprim/sulfamethoxazole in 10%, levofloxacin in 14%, gentamicin in 20%, erythromycin and/or clindamycin in 30% and penicillin in 80% of all isolates. S. aureus isolates of 15 patients revealed dynamics of resistance with increase, decrease and loss of resistant isolates to the analysed antibiotics during the study period. SCVs were isolated at least once from 42% (n = 118) of patients and mucoid isolates from 2% (n = 7) of patients. In the last study year, 89 patients were infected by S. aureus only, 44 patients by S. aureus and Pseudomonas aeruginosa and 18 by P. aeruginosa only. Patients infected by S. aureus only were younger and had better lung function compared to the other two groups. CONCLUSIONS We determined a high percentage of patients with persistent S. aureus infection. During persistence, mostly fluctuation of resistance against various antibiotics was observed in the isolates indicating acquisition and loss of resistance genes by S. aureus. The prevalence of adaptive phenotypes during long-term persistence was high for SCVs (42% of patients), but low for mucoid isolates (2% of patients), which might be underestimated for mucoid phenotypes due to the retrospective study design and the difficulty to detect mucoid isolates in primary cultures. While patients with S. aureus only had better lung function and were younger, no difference was found between the group of P. aeruginosa and S. aureus co-infection and P. aeruginosa only with previous S. aureus infection.
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Affiliation(s)
- Mathias Schwerdt
- Institute of Medical Microbiology, University Hospital Münster, Germany
| | - Claudia Neumann
- Institute of Medical Microbiology, University Hospital Münster, Germany
| | | | | | - Susann Herzog
- Institute of Medical Microbiology, University Hospital Münster, Germany
| | - Dennis Görlich
- Institute of Biostatistics and Clinical Research, University Hospital Münster, Germany
| | | | | | | | - Peter Küster
- Department of Pediatrics, Clemenshospital, Münster, Germany
| | | | - Janina Treffon
- Institute of Medical Microbiology, University Hospital Münster, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Germany
| | - Barbara C Kahl
- Institute of Medical Microbiology, University Hospital Münster, Germany.
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Suwantarat N, Rubin M, Bryan L, Tekle T, Boyle MP, Carroll KC, Jennings MT. Frequency of small-colony variants and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus in cystic fibrosis patients. Diagn Microbiol Infect Dis 2017; 90:296-299. [PMID: 29343421 DOI: 10.1016/j.diagmicrobio.2017.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/09/2017] [Accepted: 11/19/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND Small-colony variants (SCVs) are a distinct phenotype of Staphylococcus aureus, known for their role in chronic, difficult to treat infections, including cystic fibrosis (CF) lung disease. The goal of this study was to characterize SCV MRSA infection in an adult and pediatric CF population and to identify antibiotic susceptibility patterns unique to SCV MRSA. METHODS We recovered methicillin-resistant S. aureus (MRSA) from respiratory culture samples from CF patients at the Johns Hopkins Hospital during a 6month study period. RESULTS Of 1161 samples, 200 isolates (17%) were identified as MRSA, and 37 isolates from 28 patients were identified as SCV MRSA. A higher proportion of MRSA was found among SCV isolates (37/66, 56%) compared to normal colony variant (NCV) isolates (163/417, 39%), p=0.02. All SCV MRSA isolates from individual patients were susceptible to vancomycin and ceftaroline, but they demonstrated higher rates of antibiotic resistance to trimethoprim/sulfamethoxazole, moxifloxacin, and erythromycin, compared to NCV MRSA isolates. Additionally, individuals with SCV MRSA had lower lung function, higher rates of persistent MRSA infection, and higher rates of previous antibiotic use, compared to individuals with NCV MRSA. CONCLUSIONS A significant proportion of MRSA isolates recovered from patients with CF have the SCV morphology. Compared to individuals with NCV MRSA, those with SCV MRSA have higher rates of persistent MRSA infection and lower lung function. SCV MRSA isolates were more resistant than NCV, but they are highly susceptible to vancomycin, linezolid and ceftaroline.
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Affiliation(s)
- Nuntra Suwantarat
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Chulabhorn International College of Medicine, Thammasat University, PathumThani, Thailand
| | - Mayer Rubin
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Latetia Bryan
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tsigereda Tekle
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael P Boyle
- The Cystic Fibrosis Foundation, Bethesda, MD, USA; Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Karen C Carroll
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark T Jennings
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Influence of IS 256 on Genome Variability and Formation of Small-Colony Variants in Staphylococcus aureus. Antimicrob Agents Chemother 2017; 61:AAC.00144-17. [PMID: 28584147 DOI: 10.1128/aac.00144-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/30/2017] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus has acquired resistance to nearly all antibiotics used in clinical practice. Whereas some resistance mechanisms are conferred by uptake of resistance genes, others evolve by mutation. In this study, IS256 has been shown to play a role, e.g., in S. aureus strains displaying intermediate resistance to vancomycin (VISA). To characterize the IS256 insertion sites in the genomes of two closely related sequence type 247 (ST247) VISA strains, all insertions were mapped in both VISA and a susceptible control strain. The results showed that the three ST247 strains contained the highest number so far of IS256 insertions for all sequenced S. aureus strains. Furthermore, in contrast to the case with the other IS elements in these genomes, the IS256 insertion sites were not identical in the closely related strains, indicating a high transposition frequency of IS256 When IS256 was introduced into a laboratory strain which was then cultured in the presence of antibiotics, it was possible to isolate small-colony variants (SCVs) that possessed IS256 insertions in guaA and hemY that displayed increased resistance to vancomycin and aminoglycosides, respectively. For these clones, a very rapid reversion to the wild type that resembled the fast reversion of clinical SCVs was observed. The reversion was caused by excision of IS256 in a small number of fast-growing clones that quickly outcompeted the SCVs in broth cultures. In conclusion, the presence of IS256 confers a strong genomic plasticity that is useful for adaptation to antibiotic stress.
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Zhang P, Wright JA, Osman AA, Nair SP. An aroD Ochre Mutation Results in a Staphylococcus aureus Small Colony Variant That Can Undergo Phenotypic Switching via Two Alternative Mechanisms. Front Microbiol 2017; 8:1001. [PMID: 28620368 PMCID: PMC5449664 DOI: 10.3389/fmicb.2017.01001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus can undergo phenotypic switching between a normal colony phenotype (NCP) and a small colony variant (SCV). The SCV phenotype confers increased antibiotic resistance and the capacity to persist within human tissues and cells, and because these cells can revert back to the NCP they cause chronic and/or recurrent infections that are very difficult to treat. A complete picture of the genetic events that can lead to phenotypic switching in S. aureus is currently lacking. We describe the selection of an SCV with a previously unreported genetic alteration leading to an ochre mutation of aroD. In addition to the known mechanisms of phenotypic switching between the SCV and the NCP we describe a previously unreported mechanism involving tRNA ochre suppressors arising. The ochre suppressor strains had wild-type growth rates and restored antibiotic sensitivity, similar to the wild-type strain. However, whilst they had increased virulence compared to the SCV parent strain, their virulence was not restored to that of the NCP parental strain. These findings establish that phenotypic switching between the NCP and SCV states can give rise to strains with different pathogenic potential.
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Affiliation(s)
- Ping Zhang
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - John A Wright
- Immunology Catalyst, GlaxoSmithKline plcStevenage, United Kingdom
| | - Ahmed A Osman
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Sean P Nair
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
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Antibiotic tolerance and the alternative lifestyles of Staphylococcus aureus. Essays Biochem 2017; 61:71-79. [PMID: 28258231 DOI: 10.1042/ebc20160061] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/22/2016] [Accepted: 11/25/2016] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus has an incredible ability to survive, either by adapting to environmental conditions or defending against exogenous stress. Although there are certainly important genetic traits, in part this ability is provided by the breadth of modes of growth S. aureus can adopt. It has been proposed that while within their host, S. aureus survives host-generated and therapeutic antimicrobial stress via alternative lifestyles: a persister sub-population, through biofilm growth on host tissue or by growing as small colony variants (SCVs). Key to an understanding of chronic and relapsing S. aureus infections is determining the molecular basis for its switch to these quasi-dormant lifestyles. In a multicellular biofilm, the metabolically quiescent bacterial community additionally produces a highly protective extracellular polymeric substance (EPS). Furthermore, there are bacteria within a biofilm community that have an altered physiology potentially equivalent to persister cells. Recent studies have directly linked the cellular ATP production by persister cells as their key feature and the basis for their tolerance of a range of antibiotics. In clinical settings, SCVs of S. aureus have been observed for many years; when cultured, these cells form non-pigmented colonies and are approximately ten times smaller than their counterparts. Various genotypic factors have been identified in attempts to characterize S. aureus SCVs and different environmental stresses have been implicated as important inducers.
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Clinical Significance and Pathogenesis of Staphylococcal Small Colony Variants in Persistent Infections. Clin Microbiol Rev 2016; 29:401-27. [PMID: 26960941 DOI: 10.1128/cmr.00069-15] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype switch phenomenon, are presented. Moreover, relevant animal models and suggested treatment regimens, as well as the requirements for future research areas, are highlighted.
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Abstract
ABSTRACT
The immunocompromised host is a particularly vulnerable population in whom routine and unusual infections can easily and frequently occur. Prosthetic devices are commonly used in these patients and the infections associated with those devices present a number of challenges for both the microbiologist and the clinician. Biofilms play a major role in device-related infections, which may contribute to failed attempts to recover organisms from routine culture methods. Moreover, device-related microorganisms can be difficult to eradicate by antibiotic therapy alone. Changes in clinical practice and advances in laboratory diagnostics have provided significant improvements in the detection and accurate diagnosis of device-related infections. Disruption of the bacterial biofilm plays an essential role in recovering the causative agent in culture. Various culture and nucleic acid amplification techniques are more accurate to guide directed treatment regimens. This chapter reviews the performance characteristics of currently available diagnostic assays and summarizes published guidelines, where available, for addressing suspected infected prosthetic devices.
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Nyíri K, Vértessy BG. Perturbation of genome integrity to fight pathogenic microorganisms. Biochim Biophys Acta Gen Subj 2016; 1861:3593-3612. [PMID: 27217086 DOI: 10.1016/j.bbagen.2016.05.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/05/2016] [Accepted: 05/18/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Resistance against antibiotics is unfortunately still a major biomedical challenge for a wide range of pathogens responsible for potentially fatal diseases. SCOPE OF REVIEW In this study, we aim at providing a critical assessment of the recent advances in design and use of drugs targeting genome integrity by perturbation of thymidylate biosynthesis. MAJOR CONCLUSION We find that research efforts from several independent laboratories resulted in chemically highly distinct classes of inhibitors of key enzymes within the routes of thymidylate biosynthesis. The present article covers numerous studies describing perturbation of this metabolic pathway in some of the most challenging pathogens like Mycobacterium tuberculosis, Plasmodium falciparum, and Staphylococcus aureus. GENERAL SIGNIFICANCE Our comparative analysis allows a thorough summary of the current approaches to target thymidylate biosynthesis enzymes and also include an outlook suggesting novel ways of inhibitory strategies. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
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Affiliation(s)
- Kinga Nyíri
- Dept. Biotechnology, Budapest University of Technology and Economics, 4 Szent Gellért tér, Budapest HU 1111, Hungary; Institute of Enzymology, RCNS, Hungarian Academy of Sciences, 2 Magyar tudósok körútja, Budapest HU 1117, Hungary.
| | - Beáta G Vértessy
- Dept. Biotechnology, Budapest University of Technology and Economics, 4 Szent Gellért tér, Budapest HU 1111, Hungary; Institute of Enzymology, RCNS, Hungarian Academy of Sciences, 2 Magyar tudósok körútja, Budapest HU 1117, Hungary.
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Matarlo JS, Lu Y, Daryaee F, Daryaee T, Ruzsicska B, Walker SG, Tonge PJ. A Methyl 4-Oxo-4-phenylbut-2-enoate with in Vivo Activity against MRSA that Inhibits MenB in the Bacterial Menaquinone Biosynthesis Pathway. ACS Infect Dis 2016; 2:329-340. [PMID: 27294200 DOI: 10.1021/acsinfecdis.6b00023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
4-Oxo-4-phenyl-but-2-enoates inhibit MenB, the 1,4-dihydroxyl-2-naphthoyl-CoA synthase in the bacterial menaquinone (MK) biosynthesis pathway, through the formation of an adduct with coenzyme A (CoA). Here, we show that the corresponding methyl butenoates have MIC values as low as 0.35-0.75 µg/mL against drug sensitive and resistant strains of Staphylococcus aureus. Mode of action studies on the most potent compound, methyl 4-(4-chlorophenyl)-4-oxobut-2-enoate (1), reveal that 1 is converted into the corresponding CoA adduct in S. aureus cells, and that this adduct binds to the S. aureus MenB (saMenB) with a Kd value of 2 µM. The antibacterial spectrum of 1 is limited to bacteria that utilize MK for respiration, and the activity of 1 can be complemented with exogenous MK or menadione. Finally, treatment of methicillin-resistant S. aureus (MRSA) with 1 results in the small colony variant phenotype and thus 1 phenocopies knockout of the menB gene. Taken together the data indicate that the antibacterial activity of 1 results from a specific effect on MK biosynthesis. We also evaluated the in vivo efficacy of 1 using two mouse models of MRSA infection. Notably, compound 1 increased survival in a systemic infection model and resulted in a dose-dependent decrease in bacterial load in a thigh infection model, validating MenB as a target for the development of new anti-MRSA candidates.
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Affiliation(s)
- Joe S. Matarlo
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Yang Lu
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Fereidoon Daryaee
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Taraneh Daryaee
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Bela Ruzsicska
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Stephen G. Walker
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Peter J. Tonge
- Institute of Chemical Biology & Drug Discovery, Department of Chemistry, and ‡Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York 11794-3400, United States
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