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Su M, Lyles JT, Petit III RA, Peterson J, Hargita M, Tang H, Solis-Lemus C, Quave CL, Read TD. Genomic analysis of variability in Delta-toxin levels between Staphylococcus aureus strains. PeerJ 2020; 8:e8717. [PMID: 32231873 PMCID: PMC7100594 DOI: 10.7717/peerj.8717] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/10/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The delta-toxin (δ-toxin) of Staphylococcus aureus is the only hemolysin shown to cause mast cell degranulation and is linked to atopic dermatitis, a chronic inflammatory skin disease. We sought to characterize variation in δ-toxin production across S. aureus strains and identify genetic loci potentially associated with differences between strains. METHODS A set of 124 S. aureus strains was genome-sequenced and δ-toxin levels in stationary phase supernatants determined by high performance liquid chromatography (HPLC). SNPs and kmers were associated with differences in toxin production using four genome-wide association study (GWAS) methods. Transposon mutations in candidate genes were tested for their δ-toxin levels. We constructed XGBoost models to predict toxin production based on genetic loci discovered to be potentially associated with the phenotype. RESULTS The S. aureus strain set encompassed 40 sequence types (STs) in 23 clonal complexes (CCs). δ-toxin production ranged from barely detectable levels to >90,000 units, with a median of >8,000 units. CC30 had significantly lower levels of toxin production than average while CC45 and CC121 were higher. MSSA (methicillin sensitive) strains had higher δ-toxin production than MRSA (methicillin resistant) strains. Through multiple GWAS approaches, 45 genes were found to be potentially associated with toxicity. Machine learning models using loci discovered through GWAS as features were able to predict δ-toxin production (as a high/low binary phenotype) with a precision of .875 and specificity of .990 but recall of .333. We discovered that mutants in the carA gene, encoding the small chain of carbamoyl phosphate synthase, completely abolished toxin production and toxicity in Caenorhabditis elegans. CONCLUSIONS The amount of stationary phase production of the toxin is a strain-specific phenotype likely affected by a complex interaction of number of genes with different levels of effect. We discovered new candidate genes that potentially play a role in modulating production. We report for the first time that the product of the carA gene is necessary for δ-toxin production in USA300. This work lays a foundation for future work on understanding toxin regulation in S. aureus and prediction of phenotypes from genomic sequences.
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Affiliation(s)
- Michelle Su
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - James T. Lyles
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
| | - Robert A. Petit III
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Jessica Peterson
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Michelle Hargita
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Huaqiao Tang
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
| | - Claudia Solis-Lemus
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Cassandra L. Quave
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
- Department of Dermatology, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Timothy D. Read
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States of America
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102
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Jiang W, Oikonomou P, Tavazoie S. Comprehensive Genome-wide Perturbations via CRISPR Adaptation Reveal Complex Genetics of Antibiotic Sensitivity. Cell 2020; 180:1002-1017.e31. [PMID: 32109417 PMCID: PMC7169367 DOI: 10.1016/j.cell.2020.02.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/04/2019] [Accepted: 02/04/2020] [Indexed: 12/19/2022]
Abstract
Genome-wide CRISPR screens enable systematic interrogation of gene function. However, guide RNA libraries are costly to synthesize, and their limited diversity compromises the sensitivity of CRISPR screens. Using the Streptococcus pyogenes CRISPR-Cas adaptation machinery, we developed CRISPR adaptation-mediated library manufacturing (CALM), which turns bacterial cells into "factories" for generating hundreds of thousands of crRNAs covering 95% of all targetable genomic sites. With an average gene targeted by more than 100 distinct crRNAs, these highly comprehensive CRISPRi libraries produced varying degrees of transcriptional repression critical for uncovering novel antibiotic resistance determinants. Furthermore, by iterating CRISPR adaptation, we rapidly generated dual-crRNA libraries representing more than 100,000 dual-gene perturbations. The polarized nature of spacer adaptation revealed the historical contingency in the stepwise acquisition of genetic perturbations leading to increasing antibiotic resistance. CALM circumvents the expense, labor, and time required for synthesis and cloning of gRNAs, allowing generation of CRISPRi libraries in wild-type bacteria refractory to routine genetic manipulation.
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Affiliation(s)
- Wenyan Jiang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Panos Oikonomou
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Saeed Tavazoie
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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103
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Clinical Mutations That Partially Activate the Stringent Response Confer Multidrug Tolerance in Staphylococcus aureus. Antimicrob Agents Chemother 2020; 64:AAC.02103-19. [PMID: 31871080 DOI: 10.1128/aac.02103-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/18/2019] [Indexed: 12/19/2022] Open
Abstract
Antibiotic tolerance is an underappreciated antibiotic escape strategy that is associated with recurrent and relapsing infections, as well as acting as a precursor to resistance. Tolerance describes the ability of a bacterial population to survive transient exposure to an otherwise lethal concentration of antibiotic without exhibiting an elevated MIC. It is detected in time-kill assays as a lower rate of killing than a susceptible strain and can be quantified by the metric minimum duration for killing (MDK). The molecular mechanisms behind tolerance are varied, but activation of the stringent response (SR) via gene knockouts and/or chemical induction has long been associated with tolerance. More recently, two Gram-positive clinical isolates from persistent bacteremias were found to bear mutations in the SR controller, Rel, that caused elevated levels of the alarmone (p)ppGpp. Here, we show that introduction of either of these mutations into Staphylococcus aureus confers tolerance to five different classes of antibiotic as a result of (p)ppGpp-mediated growth defects (longer lag time and/or lower growth rate). The degree of tolerance is related to the severity of the growth defect and ranges from a 1.5- to 3.1-fold increase in MDK. Two classes of proposed SR inhibitor were unable to reverse or reduce this tolerance. Our findings reveal the significance of SR-activating mutations in terms of tolerance and clinical treatment failures. The panel of strains reported here provide a clinically relevant model of tolerance for further investigation of its link to resistance development, as well as potential validation of high-throughput tolerance screens.
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104
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Zhang Y, Zhang H, Wang Z, Wu Z, Wang Y, Tang N, Xu X, Zhao S, Chen W, Ji Q. Programmable adenine deamination in bacteria using a Cas9-adenine-deaminase fusion. Chem Sci 2020; 11:1657-1664. [PMID: 32206285 PMCID: PMC7069399 DOI: 10.1039/c9sc03784e] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/06/2020] [Indexed: 12/26/2022] Open
Abstract
Precise genetic manipulation is vital to studying bacterial physiology, but is difficult to achieve in some bacterial species due to the weak intrinsic homologous recombination (HR) capacity and lack of a compatible exogenous HR system. Here we report the establishment of a rapid and efficient method for directly converting adenine to guanine in bacterial genomes using the fusion of an adenine deaminase and a Cas9 nickase. The method achieves the conversion of adenine to guanine via an enzymatic deamination reaction and a subsequent DNA replication process rather than HR, which is utilized in conventional bacterial genetic manipulation methods, thereby substantially simplifying the genome editing process. A systematic screening targeting the possibly editable adenine sites of cntBC, the importer of the staphylopine/metal complex in Staphylococcus aureus, pinpoints key residues for metal importation, demonstrating that application of the system would greatly facilitate the genomic engineering of bacteria.
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Affiliation(s)
- Ya Zhang
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
- University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Hongyuan Zhang
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
- University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Zhipeng Wang
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
- University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Zhaowei Wu
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
| | - Yu Wang
- College of Life Science and Engineering , Jiangxi Agricultural University , Nanchang 330045 , China
| | - Na Tang
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
- University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Xuexia Xu
- iHuman Institute , ShanghaiTech University , Shanghai 201210 , China
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , China
| | - Suwen Zhao
- iHuman Institute , ShanghaiTech University , Shanghai 201210 , China
- School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , China
| | - Weizhong Chen
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
| | - Quanjiang Ji
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . ;
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105
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Zeden MS, Kviatkovski I, Schuster CF, Thomas VC, Fey PD, Gründling A. Identification of the main glutamine and glutamate transporters in Staphylococcus aureus and their impact on c-di-AMP production. Mol Microbiol 2020; 113:1085-1100. [PMID: 31997474 PMCID: PMC7299772 DOI: 10.1111/mmi.14479] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/22/2020] [Indexed: 12/19/2022]
Abstract
A Staphylococcus aureus strain deleted for the c‐di‐AMP cyclase gene dacA is unable to survive in rich medium unless it acquires compensatory mutations. Previously identified mutations were in opuD, encoding the main glycine‐betaine transporter, and alsT, encoding a predicted amino acid transporter. Here, we show that inactivation of OpuD restores the cell size of a dacA mutant to near wild‐type (WT) size, while inactivation of AlsT does not. AlsT was identified as an efficient glutamine transporter, indicating that preventing glutamine uptake in rich medium rescues the growth of the S. aureus dacA mutant. In addition, GltS was identified as a glutamate transporter. By performing growth curves with WT, alsT and gltS mutant strains in defined medium supplemented with ammonium, glutamine or glutamate, we revealed that ammonium and glutamine, but not glutamate promote the growth of S. aureus. This suggests that besides ammonium also glutamine can serve as a nitrogen source under these conditions. Ammonium and uptake of glutamine via AlsT and hence likely a higher intracellular glutamine concentration inhibited c‐di‐AMP production, while glutamate uptake had no effect. These findings provide, besides the previously reported link between potassium and osmolyte uptake, a connection between nitrogen metabolism and c‐di‐AMP signalling in S. aureus.
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Affiliation(s)
- Merve S Zeden
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Igor Kviatkovski
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Christopher F Schuster
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Vinai C Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Angelika Gründling
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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Depardieu F, Bikard D. Gene silencing with CRISPRi in bacteria and optimization of dCas9 expression levels. Methods 2020; 172:61-75. [PMID: 31377338 DOI: 10.1016/j.ymeth.2019.07.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/25/2019] [Accepted: 07/29/2019] [Indexed: 12/15/2022] Open
Abstract
The catalytic null mutant of the Cas9 endonuclease from the bacterial CRISPR immune system, known as dCas9, can be guided by a small RNA to bind DNA sequences of interest and block gene transcription in a strategy known as CRISPRi. This powerful gene silencing method has already been used in a large number of species and in high throughput screens. Here we provide detailed design rules, methods and novel vectors to perform CRISPRi experiments in S. aureus and in E. coli, using the well characterized dCas9 protein from S. pyogenes. In particular, we describe a vector based on plasmid pC194 which is broadly used in Firmicutes, as well as a vector based on the very broad host-range rolling circle plasmid pLZ12, reported to replicate in both Firmicutes and Proteobacteria. A potential caveat of adapting dCas9 tools to various bacterial species is that dCas9 was shown to be toxic when expressed too strongly. We describe a method to optimize the expression level of dCas9 in order to avoid toxicity while ensuring strong on-target repression activity. We demonstrate this method by optimizing a pLZ12 based vector originally developed for S. aureus so that it can work in E. coli. This article should provide all the resources required to perform CRISPRi experiments in a broad range of bacterial species.
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Affiliation(s)
| | - David Bikard
- Groupe de Biologie de Synthèse, Institut Pasteur, Paris 75015, France.
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107
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Comparative Transcriptomic and Functional Assessments of Linezolid-Responsive Small RNA Genes in Staphylococcus aureus. mSystems 2020; 5:5/1/e00665-19. [PMID: 31911464 PMCID: PMC6946794 DOI: 10.1128/msystems.00665-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are RNA molecules that can have important regulatory roles across gene expression networks. There is a growing understanding of the scope and potential breadth of impact of sRNAs on global gene expression patterns in Staphylococcus aureus, a major human pathogen. Here, transcriptome comparisons were used to examine the roles of sRNA genes with a potential role in the response of S. aureus to antibiotic exposure. Although no measurable impact on key bacterial phenotypes was observed after deleting each of 18 sRNAs identified by these comparisons, this research is significant because it underscores the subtle modes of action of these sometimes abundant molecules within the bacterium. Staphylococcus aureus contains a repertoire of at least 50 and possibly 500 small RNAs (sRNAs). The functions of most sRNAs are not understood, although some are known to respond to environmental changes, including the presence of antibiotics. Here, in an effort to better understand the roles of sRNAs in the context of antibiotic exposure, we took a clinical methicillin-resistant S. aureus (MRSA) isolate and separately deleted eight sRNAs that were significantly upregulated in response to the last-line antibiotic linezolid as revealed by transcriptome sequencing (RNA-seq) comparisons. We also deleted an additional 10 sRNAs that were either highly expressed or previously found to respond to antibiotic exposure. There were no significant changes for any of the 18 mutants in a variety of phenotypic screens, including MIC screens, growth competition assays in the presence of linezolid, biofilm formation, and resistance to whole-blood killing. These data suggest sRNA functional redundancy, because despite their high expression levels upon antibiotic exposure, individual sRNA genes do not affect readily observable bacterial phenotypes. The sRNA transcriptional changes we measured during antibiotic exposure might also reflect sRNA “indifference,” that is, a general stress response not specifically related to sRNA function. These data underscore the need for sensitive assays and new approaches to try and decipher the functions of sRNA genes in S. aureus. IMPORTANCE Bacterial small RNAs (sRNAs) are RNA molecules that can have important regulatory roles across gene expression networks. There is a growing understanding of the scope and potential breadth of impact of sRNAs on global gene expression patterns in Staphylococcus aureus, a major human pathogen. Here, transcriptome comparisons were used to examine the roles of sRNA genes with a potential role in the response of S. aureus to antibiotic exposure. Although no measurable impact on key bacterial phenotypes was observed after deleting each of 18 sRNAs identified by these comparisons, this research is significant because it underscores the subtle modes of action of these sometimes abundant molecules within the bacterium.
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108
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Genome Editing in Staphylococcus aureus by Conditional Recombineering and CRISPR/Cas9-Mediated Counterselection. Methods Mol Biol 2020; 2050:127-143. [PMID: 31468487 DOI: 10.1007/978-1-4939-9740-4_14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Methods for the genetic manipulation of S. aureus have historically proven challenging, which has hindered experimental studies of this organism. We recently developed a system for recombineering and CRISPR/Cas9-mediated counterselection in S. aureus which utilizes commercially synthesized synthetic DNA oligonucleotides as substrates for introducing precise genomic modifications into the organism and for performing lethal counterselection of unedited cells. These techniques make it possible to scalably and inexpensively engineer desired genomic changes into laboratory or clinical S. aureus strains, using electroporation to introduce the effector plasmid vectors and oligonucleotides. Here we describe detailed protocols for performing genome editing of S. aureus in order to produce isogenic strains using this system and detail general principles which are broadly applicable across a range of organisms for which equivalent systems have been established.
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109
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Mining the Methylome Reveals Extensive Diversity in Staphylococcus epidermidis Restriction Modification. mBio 2019; 10:mBio.02451-19. [PMID: 31848274 PMCID: PMC6918075 DOI: 10.1128/mbio.02451-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus epidermidis is a significant opportunistic pathogen of humans. Molecular studies in this species have been hampered by the presence of restriction-modification (RM) systems that limit introduction of foreign DNA. Here, we establish the complete genomes and methylomes for seven clinically significant, genetically diverse S. epidermidis isolates and perform the first systematic genomic analyses of the type I RM systems within both S. epidermidis and Staphylococcus aureus Our analyses revealed marked differences in the gene arrangement, chromosomal location, and movement of type I RM systems between the two species. Unlike S. aureus, S. epidermidis type I RM systems demonstrate extensive diversity even within a single genetic lineage. This is contrary to current assumptions and has important implications for approaching the genetic manipulation of S. epidermidis Using Escherichia coli plasmid artificial modification (PAM) to express S. epidermidis hsdMS, we readily overcame restriction barriers in S. epidermidis and achieved electroporation efficiencies equivalent to those of modification-deficient mutants. With these functional experiments, we demonstrated how genomic data can be used to predict both the functionality of type I RM systems and the potential for a strain to be electroporation proficient. We outline an efficient approach for the genetic manipulation of S. epidermidis strains from diverse genetic backgrounds, including those that have hitherto been intractable. Additionally, we identified S. epidermidis BPH0736, a naturally restriction-defective, clinically significant, multidrug-resistant ST2 isolate, as an ideal candidate for molecular studies.IMPORTANCE Staphylococcus epidermidis is a major cause of hospital-acquired infections, especially those related to implanted medical devices. Understanding how S. epidermidis causes disease and devising ways to combat these infections have been hindered by an inability to genetically manipulate clinically significant hospital-adapted strains. Here, we provide the first comprehensive analyses of the barriers to the uptake of foreign DNA in S. epidermidis and demonstrate that these are distinct from those described for S. aureus Using these insights, we demonstrate an efficient approach for the genetic manipulation of S. epidermidis to enable the study of clinical isolates for the first time.
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110
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Shi L, Stachon T, Latta L, Elhawy MI, Gunaratnam G, Orosz E, Kiderlen AF, Seitz B, Bischoff M, Szentmáry N. Comparison of in vitro assays to study the effectiveness of antiparasitics against Acanthamoeba castellani trophozoites and cysts. Acta Microbiol Immunol Hung 2019; 67:23-32. [PMID: 31833381 DOI: 10.1556/030.66.2019.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 07/12/2019] [Indexed: 12/11/2022]
Abstract
We aimed to compare LDH release assay, trypan blue and fluorescent stainings, and non-nutrient Escherichia coli plate assay in determining treatment efficacy of antiamoebic agents against Acanthamoeba castellanii trophozoites/cysts, in vitro. 1BU trophozoites/cysts were challenged with 0.02% polyhexamethylene biguanid (PHMB), 0.1% propamidine isethionate (PD), and 0.0065% miltefosine (MF). Efficacies of the drugs were determined by LDH release and trypan blue assays, by Hoechst 33343, calcein-AM, and ethidium homodimer-1 fluorescent dyes, and by a non-nutrient agar E. coli plate assay. All three antiamoebic agents induced a significant LDH release from trophozoites, compared to controls (p < 0.0001). Fluorescent-dye staining in untreated 1BU trophozoites/cysts was negligible, but using antiamoebic agents, there was 59.3%-100% trypan blue, 100% Hoechst 33342, 0%-75.3% calcein-AM, and 100% ethidium homodimer-1 positivity. On E. coli plates, in controls and MF-treated 1BU trophozoites/cysts, new trophozoites appeared within 24 h, encystment occurred after 5 weeks. In PHMB- and PD-treated 1BU throphozoites/cysts, irregularly shaped, smaller trophozoites appeared after 72 h, which failed to form new cysts within 5 weeks. None of the enzymatic- and dye-based viability assays tested here generated survival rates for trophozoites/cysts that were comparable with those yielded with the non-nutrient agar E. coli plate assay, suggesting that the culture-based assay is the best method to study the treatment efficacy of drugs against Acanthamoeba.
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Affiliation(s)
- Lei Shi
- Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, P. R. China
| | - Tanja Stachon
- Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Lorenz Latta
- Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Mohamed Ibrahem Elhawy
- Institute for Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Gubesh Gunaratnam
- Institute for Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Erika Orosz
- Department of Parasitology, National Public Health Center, Budapest, Hungary
| | | | - Berthold Seitz
- Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany
| | - Markus Bischoff
- Institute for Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Nóra Szentmáry
- Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
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111
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Roch M, Lelong E, Panasenko OO, Sierra R, Renzoni A, Kelley WL. Thermosensitive PBP2a requires extracellular folding factors PrsA and HtrA1 for Staphylococcus aureus MRSA β-lactam resistance. Commun Biol 2019; 2:417. [PMID: 31754647 PMCID: PMC6858329 DOI: 10.1038/s42003-019-0667-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/25/2019] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen and represents a clinical challenge because of widespread antibiotic resistance. Methicillin resistant Staphylococcus aureus (MRSA) is particularly problematic and originates by the horizontal acquisition of mecA encoding PBP2a, an extracellular membrane anchored transpeptidase, which confers resistance to β-lactam antibiotics by allosteric gating of its active site channel. Herein, we show that dual disruption of PrsA, a lipoprotein chaperone displaying anti-aggregation activity, together with HtrA1, a membrane anchored chaperone/serine protease, resulted in severe and synergistic attenuation of PBP2a folding that restores sensitivity to β-lactams such as oxacillin. Purified PBP2a has a pronounced unfolding transition initiating at physiological temperatures that leads to irreversible precipitation and complete loss of activity. The concordance of genetic and biochemical data highlights the necessity for extracellular protein folding factors governing MRSA β-lactam resistance. Targeting the PBP2a folding pathway represents a particularly attractive adjuvant strategy to combat antibiotic resistance.
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Affiliation(s)
- Mélanie Roch
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1 rue Michel-Servet, Geneva, CH-1211 Switzerland
| | - Emmanuelle Lelong
- Service of Infectious Diseases and Department of Medical Specialties, University Hospital and Medical School of Geneva, 4 rue Gabrielle-Perret-Gentil, Geneva, CH-1206 Switzerland
| | - Olesya O. Panasenko
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1 rue Michel-Servet, Geneva, CH-1211 Switzerland
- Service of Infectious Diseases and Department of Medical Specialties, University Hospital and Medical School of Geneva, 4 rue Gabrielle-Perret-Gentil, Geneva, CH-1206 Switzerland
| | - Roberto Sierra
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1 rue Michel-Servet, Geneva, CH-1211 Switzerland
| | - Adriana Renzoni
- Service of Infectious Diseases and Department of Medical Specialties, University Hospital and Medical School of Geneva, 4 rue Gabrielle-Perret-Gentil, Geneva, CH-1206 Switzerland
| | - William L. Kelley
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, 1 rue Michel-Servet, Geneva, CH-1211 Switzerland
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Staphylococcus aureus small colony variants impair host immunity by activating host cell glycolysis and inducing necroptosis. Nat Microbiol 2019; 5:141-153. [PMID: 31686028 PMCID: PMC10184863 DOI: 10.1038/s41564-019-0597-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/19/2019] [Indexed: 01/29/2023]
Abstract
Staphylococcus aureus small colony variants (SCVs) are frequently associated with chronic infection, yet they lack expression of many virulence determinants associated with the pathogenicity of wild-type strains. We found that both wild-type S. aureus and a ΔhemB SCV prototype potently activate glycolysis in host cells. Glycolysis and the generation of mitochondrial reactive oxygen species were sufficient to induce necroptosis, a caspase-independent mechanism of host cell death that failed to eradicate S. aureus and instead promoted ΔhemB SCV pathogenicity. To support ongoing glycolytic activity, the ΔhemB SCV induced over a 100-fold increase in the expression of fumC, which encodes an enzyme that catalyses the degradatin of fumarate, an inhibitor of glycolysis. Consistent with fumC-dependent depletion of local fumarate, the ΔhemB SCV failed to elicit trained immunity and protection from a secondary infectious challenge in the skin. The reliance of the S. aureus SCV population on glycolysis accounts for much of its role in the pathogenesis of S. aureus skin infection.
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113
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Patton T, Jiang JH, Lundie RJ, Bafit M, Gao W, Peleg AY, O'Keeffe M. Daptomycin-resistant Staphylococcus aureus clinical isolates are poorly sensed by dendritic cells. Immunol Cell Biol 2019; 98:42-53. [PMID: 31559654 DOI: 10.1111/imcb.12295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/18/2019] [Accepted: 09/23/2019] [Indexed: 12/18/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) presents an increasing threat to public health, with antimicrobial resistance on the rise and infections endemic in the hospital setting. Despite a global research effort to understand and combat antimicrobial resistance, less work has focused on understanding the nuances in the immunopathogenesis of clinical strains. In particular, there is a surprising gap of knowledge in the literature pertaining to how clinical strains are recognized by dendritic cells (DCs). Here, we show that the activation of DCs is compromised in response to MRSA strains resistant to the last-line antibiotic daptomycin. We found a significant reduction in the secretion of proinflammatory cytokines including tumor necrosis factor-α, interleukin-6, regulated upon activation, normal T cell expressed, and secreted and macrophage inflammatory protein-1β, as well as decreased expression of CD80 by DCs responding to daptomycin-resistant MRSA. We further demonstrate that this phenotype is coincident with the acquisition of specific point mutations in the cardiolipin synthase gene cls2, and, partly, in the bifunctional lysylphosphatidylglycerol flippase/synthetase gene mprF, which are genes that are often mutated in clinical daptomycin-resistant strains. Therefore, throughout infection and antibiotic therapy, MRSA has the capacity to not only develop further antibiotic resistance, but also develop resistance to immunological recognition by DCs, because of single amino acid point mutations occurring under the selective pressures of both host immunity and antibiotic therapy. Understanding the diversity of clinical MRSA isolates and the nuances in their immune recognition will have important implications for future therapeutics and the treatment of these infections.
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Affiliation(s)
- Timothy Patton
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
| | - Jhih-Hang Jiang
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC, 3800, Australia
| | - Rachel J Lundie
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
| | - Mariam Bafit
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
| | - Wei Gao
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infectious Diseases, Melbourne, VIC, 3000, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC, 3800, Australia.,Department of Infectious Diseases, The Alfred and Central Clinical School, Monash University, Melbourne, VIC, 3000, Australia
| | - Meredith O'Keeffe
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
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114
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Berti AD, Shukla N, Rottier AD, McCrone JS, Turner HM, Monk IR, Baines SL, Howden BP, Proctor RA, Rose WE. Daptomycin selects for genetic and phenotypic adaptations leading to antibiotic tolerance in MRSA. J Antimicrob Chemother 2019; 73:2030-2033. [PMID: 29718242 DOI: 10.1093/jac/dky148] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/26/2018] [Indexed: 12/16/2022] Open
Abstract
Objectives Daptomycin non-susceptibility in Staphylococcus aureus can emerge via the accumulation of single or multiple mutations, each resulting in a slight increase in the daptomycin MIC. The daptomycin-non-susceptible phenotype may include other features such as daptomycin tolerance. This study identifies S. aureus genomic regions that frequently develop mutations following prolonged daptomycin exposure but have not been previously associated with daptomycin non-susceptibility. Methods Sequence variations in the same eight loci independently observed following 28 day parallel serial passages of S. aureus J01 in daptomycin were introduced in isolation into S. aureus J01. MICs were determined by microbroth dilution. Daptomycin killing and tolerance were determined by kill curve analysis. Results Single mutations in snoF, hmp1, sspA, rimP, hepT, rsh, map1 and amaP had only a modest impact on the daptomycin MIC (≤2-fold). In contrast, individual mutation in several of these regions resulted in pronounced changes to daptomycin tolerance. Conclusions This study demonstrates that less characterized mutations in S. aureus following daptomycin exposure do not result in significant daptomycin susceptibility changes, but rather allow for enhanced survival characteristics during treatment. This sheds new light on genetic adaptations that may play a role in persistent infection. Further studies are needed to elucidate the prevalence of these mutations in clinical isolates.
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Affiliation(s)
- Andrew D Berti
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA.,Department of Pharmacy Practice, Wayne State University, Detroit, MI, USA
| | - Neehal Shukla
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA
| | - Aaron D Rottier
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA
| | - J Sue McCrone
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA
| | - Hannah M Turner
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA
| | - Ian R Monk
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sarah L Baines
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Benjamin P Howden
- Doherty Applied Microbial Genomics, Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.,Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.,Infectious Diseases Department, Austin Health, Melbourne, Victoria, Australia
| | - Richard A Proctor
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.,Department of Medical Microbiology/Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Warren E Rose
- Pharmacy Practice Division, University of Wisconsin-Madison, Madison, WI, USA.,Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
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115
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Pidot SJ, Gao W, Buultjens AH, Monk IR, Guerillot R, Carter GP, Lee JYH, Lam MMC, Grayson ML, Ballard SA, Mahony AA, Grabsch EA, Kotsanas D, Korman TM, Coombs GW, Robinson JO, Gonçalves da Silva A, Seemann T, Howden BP, Johnson PDR, Stinear TP. Increasing tolerance of hospital Enterococcus faecium to handwash alcohols. Sci Transl Med 2019; 10:10/452/eaar6115. [PMID: 30068573 DOI: 10.1126/scitranslmed.aar6115] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 02/10/2018] [Accepted: 04/03/2018] [Indexed: 11/03/2022]
Abstract
Alcohol-based disinfectants and particularly hand rubs are a key way to control hospital infections worldwide. Such disinfectants restrict transmission of pathogens, such as multidrug-resistant Staphylococcus aureus and Enterococcus faecium Despite this success, health care infections caused by E. faecium are increasing. We tested alcohol tolerance of 139 hospital isolates of E. faecium obtained between 1997 and 2015 and found that E. faecium isolates after 2010 were 10-fold more tolerant to killing by alcohol than were older isolates. Using a mouse gut colonization model of E. faecium transmission, we showed that alcohol-tolerant E. faecium resisted standard 70% isopropanol surface disinfection, resulting in greater mouse gut colonization compared to alcohol-sensitive E. faecium We next looked for bacterial genomic signatures of adaptation. Alcohol-tolerant E. faecium accumulated mutations in genes involved in carbohydrate uptake and metabolism. Mutagenesis confirmed the roles of these genes in the tolerance of E. faecium to isopropanol. These findings suggest that bacterial adaptation is complicating infection control recommendations, necessitating additional procedures to prevent E. faecium from spreading in hospital settings.
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Affiliation(s)
- Sacha J Pidot
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Wei Gao
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Andrew H Buultjens
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Ian R Monk
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Romain Guerillot
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Glen P Carter
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Jean Y H Lee
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Margaret M C Lam
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - M Lindsay Grayson
- Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia.,Department of Medicine, University of Melbourne, Heidelberg, Victoria 3084, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Victoria 3800, Australia
| | - Susan A Ballard
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Andrew A Mahony
- Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Elizabeth A Grabsch
- Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Despina Kotsanas
- Monash Infectious Diseases, Monash Health, Clayton, Victoria 3168, Australia
| | - Tony M Korman
- Monash Infectious Diseases, Monash Health, Clayton, Victoria 3168, Australia
| | - Geoffrey W Coombs
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.,Department of Microbiology, PathWest Laboratory Medicine WA, Fiona Stanley Hospital, Murdoch, Western Australia 6150, Australia
| | - J Owen Robinson
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.,Department of Microbiology, PathWest Laboratory Medicine WA, Fiona Stanley Hospital, Murdoch, Western Australia 6150, Australia
| | - Anders Gonçalves da Silva
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Torsten Seemann
- Melbourne Bioinformatics, University of Melbourne, Carlton, Victoria 3053, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia.,Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia.,Department of Medicine, University of Melbourne, Heidelberg, Victoria 3084, Australia.,Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Paul D R Johnson
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia. .,Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia.,Department of Medicine, University of Melbourne, Heidelberg, Victoria 3084, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia.
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116
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Unstable chromosome rearrangements in Staphylococcus aureus cause phenotype switching associated with persistent infections. Proc Natl Acad Sci U S A 2019; 116:20135-20140. [PMID: 31527262 PMCID: PMC6778178 DOI: 10.1073/pnas.1904861116] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen known to exhibit subpopulations of small-colony variants (SCVs) that cause persistent or recurrent infections. The underlying mechanisms promoting the SCV phenotypic switching and adaptation to persistent infection are poorly understood. Moreover, the instability of this frequently reverting phenotype hampers diagnosis and study. Here we show that SCVs with reduced virulence but increased immune evasion and persistence properties can arise from reversible chromosomal instability. This mechanism of SCV generation implies an asymmetric chromosome inversion and the activation of prophage-encoding genes used for immune evasion. Assessment of major S. aureus lineages indicates this genomic plasticity is a common but previously unrecognized mechanism used by S. aureus to cause persistent and relapsing infections. Staphylococcus aureus small-colony variants (SCVs) are associated with unusually chronic and persistent infections despite active antibiotic treatment. The molecular basis for this clinically important phenomenon is poorly understood, hampered by the instability of the SCV phenotype. Here we investigated the genetic basis for an unstable S. aureus SCV that arose spontaneously while studying rifampicin resistance. This SCV showed no nucleotide differences across its genome compared with a normal-colony variant (NCV) revertant, yet the SCV presented the hallmarks of S. aureus linked to persistent infection: down-regulation of virulence genes and reduced hemolysis and neutrophil chemotaxis, while exhibiting increased survival in blood and ability to invade host cells. Further genome analysis revealed chromosome structural variation uniquely associated with the SCV. These variations included an asymmetric inversion across half of the S. aureus chromosome via recombination between type I restriction modification system (T1RMS) genes, and the activation of a conserved prophage harboring the immune evasion cluster (IEC). Phenotypic reversion to the wild-type–like NCV state correlated with reversal of the chromosomal inversion (CI) and with prophage stabilization. Further analysis of 29 complete S. aureus genomes showed strong signatures of recombination between hsdMS genes, suggesting that analogous CI has repeatedly occurred during S. aureus evolution. Using qPCR and long-read amplicon deep sequencing, we detected subpopulations with T1RMS rearrangements causing CIs and prophage activation across major S. aureus lineages. Here, we have discovered a previously unrecognized and widespread mechanism of reversible genomic instability in S. aureus associated with SCV generation and persistent infections.
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117
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Bojer MS, Wacnik K, Kjelgaard P, Gallay C, Bottomley AL, Cohn MT, Lindahl G, Frees D, Veening JW, Foster SJ, Ingmer H. SosA inhibits cell division in Staphylococcus aureus in response to DNA damage. Mol Microbiol 2019; 112:1116-1130. [PMID: 31290194 PMCID: PMC6851548 DOI: 10.1111/mmi.14350] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2019] [Indexed: 01/10/2023]
Abstract
Inhibition of cell division is critical for viability under DNA‐damaging conditions. DNA damage induces the SOS response that in bacteria inhibits cell division while repairs are being made. In coccoids, such as the human pathogen, Staphylococcus aureus, this process remains poorly studied. Here, we identify SosA as the staphylococcal SOS‐induced cell division inhibitor. Overproduction of SosA inhibits cell division, while sosA inactivation sensitizes cells to genotoxic stress. SosA is a small, predicted membrane protein with an extracellular C‐terminal domain in which point mutation of residues that are conserved in staphylococci and major truncations abolished the inhibitory activity. In contrast, a minor truncation led to SosA accumulation and a strong cell division inhibitory activity, phenotypically similar to expression of wild‐type SosA in a CtpA membrane protease mutant. This suggests that the extracellular C‐terminus of SosA is required both for cell division inhibition and for turnover of the protein. Microscopy analysis revealed that SosA halts cell division and synchronizes the cell population at a point where division proteins such as FtsZ and EzrA are localized at midcell, and the septum formation is initiated but unable to progress to closure. Thus, our findings show that SosA is central in cell division regulation in staphylococci.
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Affiliation(s)
- Martin S Bojer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Centre for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Katarzyna Wacnik
- Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield, UK
| | - Peter Kjelgaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Clement Gallay
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Amy L Bottomley
- Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield, UK
| | - Marianne T Cohn
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gunnar Lindahl
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield, UK
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Centre for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
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118
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Tuffs SW, Herfst CA, Baroja ML, Podskalniy VA, DeJong EN, Coleman CEM, McCormick JK. Regulation of toxic shock syndrome toxin‐1 by the accessory gene regulator inStaphylococcus aureusis mediated by the repressor of toxins. Mol Microbiol 2019; 112:1163-1177. [DOI: 10.1111/mmi.14353] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Stephen W. Tuffs
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
| | - Christine A. Herfst
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
- Lawson Health Research Institute London Ontario Canada
| | - Miren L. Baroja
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
- Lawson Health Research Institute London Ontario Canada
| | - Vladyslav A. Podskalniy
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
| | - Erica N. DeJong
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
| | - Charlotte E. M. Coleman
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
| | - John K. McCormick
- Department of Microbiology and Immunology University of Western Ontario London Ontario Canada
- Lawson Health Research Institute London Ontario Canada
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119
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Monk IR, Shaikh N, Begg SL, Gajdiss M, Sharkey LKR, Lee JYH, Pidot SJ, Seemann T, Kuiper M, Winnen B, Hvorup R, Collins BM, Bierbaum G, Udagedara SR, Morey JR, Pulyani N, Howden BP, Maher MJ, McDevitt CA, King GF, Stinear TP. Zinc-binding to the cytoplasmic PAS domain regulates the essential WalK histidine kinase of Staphylococcus aureus. Nat Commun 2019; 10:3067. [PMID: 31296851 PMCID: PMC6624279 DOI: 10.1038/s41467-019-10932-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 06/05/2019] [Indexed: 01/23/2023] Open
Abstract
WalKR (YycFG) is the only essential two-component regulator in the human pathogen Staphylococcus aureus. WalKR regulates peptidoglycan synthesis, but this function alone does not explain its essentiality. Here, to further understand WalKR function, we investigate a suppressor mutant that arose when WalKR activity was impaired; a histidine to tyrosine substitution (H271Y) in the cytoplasmic Per-Arnt-Sim (PASCYT) domain of the histidine kinase WalK. Introducing the WalKH271Y mutation into wild-type S. aureus activates the WalKR regulon. Structural analyses of the WalK PASCYT domain reveal a metal-binding site, in which a zinc ion (Zn2+) is tetrahedrally-coordinated by four amino acids including H271. The WalKH271Y mutation abrogates metal binding, increasing WalK kinase activity and WalR phosphorylation. Thus, Zn2+-binding negatively regulates WalKR. Promoter-reporter experiments using S. aureus confirm Zn2+ sensing by this system. Identification of a metal ligand recognized by the WalKR system broadens our understanding of this critical S. aureus regulon.
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Affiliation(s)
- Ian R Monk
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.
| | - Nausad Shaikh
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Stephanie L Begg
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Mike Gajdiss
- University Clinics of Bonn, Institute of Medical Microbiology, Immunology and Parasitology, 53127, Bonn, Germany
| | - Liam K R Sharkey
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Jean Y H Lee
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Sacha J Pidot
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Torsten Seemann
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.,Melbourne Bioinformatics, University of Melbourne, Melbourne, VIC, 3000, Australia
| | | | | | - Rikki Hvorup
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Gabriele Bierbaum
- University Clinics of Bonn, Institute of Medical Microbiology, Immunology and Parasitology, 53127, Bonn, Germany
| | - Saumya R Udagedara
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Jacqueline R Morey
- Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Neha Pulyani
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Megan J Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Christopher A McDevitt
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.,Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.
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120
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Foster TJ. Surface Proteins of Staphylococcus aureus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0046-2018. [PMID: 31267926 PMCID: PMC10957221 DOI: 10.1128/microbiolspec.gpp3-0046-2018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
The surface of Staphylococcus aureus is decorated with over 20 proteins that are covalently anchored to peptidoglycan by the action of sortase A. These cell wall-anchored (CWA) proteins can be classified into several structural and functional groups. The largest is the MSCRAMM family, which is characterized by tandemly repeated IgG-like folded domains that bind peptide ligands by the dock lock latch mechanism or the collagen triple helix by the collagen hug. Several CWA proteins comprise modules that have different functions, and some individual domains can bind different ligands, sometimes by different mechanisms. For example, the N-terminus of the fibronectin binding proteins comprises an MSCRAMM domain which binds several ligands, while the C-terminus is composed of tandem fibronectin binding repeats. Surface proteins promote adhesion to host cells and tissue, including components of the extracellular matrix, contribute to biofilm formation by stimulating attachment to the host or indwelling medical devices followed by cell-cell accumulation via homophilic interactions between proteins on neighboring cells, help bacteria evade host innate immune responses, participate in iron acquisition from host hemoglobin, and trigger invasion of bacteria into cells that are not normally phagocytic. The study of genetically manipulated strains using animal infection models has shown that many CWA proteins contribute to pathogenesis. Fragments of CWA proteins have the potential to be used in multicomponent vaccines to prevent S. aureus infections.
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121
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Candida albicans Augments Staphylococcus aureus Virulence by Engaging the Staphylococcal agr Quorum Sensing System. mBio 2019; 10:mBio.00910-19. [PMID: 31164467 PMCID: PMC6550526 DOI: 10.1128/mbio.00910-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Relatively little is known about the complex interactions and signaling events that occur between microbes and even less so about how microbial “cross talk” shapes human health and disease. Candida albicans (a fungus) and Staphylococcus aureus (a bacterium) are formidable human nosocomial pathogens, causing severe morbidity and mortality. Moreover, they are frequently coisolated from central venous catheters and deep-seated infections, including intra-abdominal sepsis. In this work, we have shown that coinfection with C. albicans and S. aureus is highly lethal, leading to >80% mortality by day 1 postinfection, whereas monoinfection with C. albicans or S. aureus does not cause mortality. This infectious synergism is dependent on the expression of staphylococcal alpha-toxin, and secretion of this potent virulence factor is actually augmented by C. albicans via an agr-dependent mechanism. Moreover, prophylactic neutralization of alpha-toxin with a monoclonal antibody is sufficient to elicit protection during coinfection. Therefore, we have demonstrated that a pathogenic fungus can enhance virulence determinants of a bacterium in vivo with devastating consequences to the host. These results have important implications in the surveillance and treatment of polymicrobial disease and highlight the dynamic intersection of environment, pathogens, and host. Candida albicans and Staphylococcus aureus are among the most prevalent nosocomial pathogens that are responsible for severe morbidity and mortality, even with appropriate treatment. Using a murine model of polymicrobial intra-abdominal infection (IAI), we have previously shown that coinfection with these pathogens results in synergistic lethality that is partially dependent on exacerbated prostaglandin signaling, while monomicrobial infection is nonlethal. Therefore, the objective of this study was to identify staphylococcal virulence determinants that drive lethal synergism during polymicrobial IAI. Using the toxigenic S. aureus strain JE2, we observed that coinfection with C. albicans led to a striking 80 to 100% mortality rate within 20 h postinoculation (p.i.) while monomicrobial infections were nonlethal. Use of a green fluorescent protein (GFP)-P3 promoter S. aureus reporter strain revealed enhanced activation of the staphylococcal agr quorum sensing system during in vitro polymicrobial versus monomicrobial growth. Analyses by quantitative real-time PCR (qPCR), Western blot, and toxin functional assays confirmed enhanced agr-associated gene transcription and increases in secreted alpha- and delta-toxins. C. albicans-mediated elevated toxin production and hemolytic activity were determined to be agrA dependent, and genetic knockout and complementation of hla identified alpha-toxin as the key staphylococcal virulence factor driving lethal synergism. Analysis of mono- and polymicrobial infections 8 h p.i. demonstrated equivalent bacterial burdens in the peritoneal cavity but significantly elevated levels of alpha-toxin (3-fold) and the eicosanoid prostaglandin E2 (PGE2) (4-fold) during coinfection. Importantly, prophylactic passive immunization using the monoclonal anti-alpha-toxin antibody MEDI4893* led to significantly improved survival rates compared to those following treatment with isotype control antibody. Collectively, these results define alpha-toxin as an essential virulence determinant during C. albicans-S. aureus IAI and describe a novel mechanism by which a human-pathogenic fungus can augment the virulence of a highly pathogenic bacterium in vivo.
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122
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Schuster CF, Howard SA, Gründling A. Use of the counter selectable marker PheS* for genome engineering in Staphylococcus aureus. Microbiology (Reading) 2019; 165:572-584. [DOI: 10.1099/mic.0.000791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Christopher F. Schuster
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Sophie A. Howard
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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Clumping factor B is an important virulence factor during Staphylococcus aureus skin infection and a promising vaccine target. PLoS Pathog 2019; 15:e1007713. [PMID: 31009507 PMCID: PMC6497315 DOI: 10.1371/journal.ppat.1007713] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 05/02/2019] [Accepted: 03/19/2019] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus expresses a number of cell wall-anchored proteins that mediate adhesion and invasion of host cells and tissues and promote immune evasion, consequently contributing to the virulence of this organism. The cell wall-anchored protein clumping factor B (ClfB) has previously been shown to facilitate S. aureus nasal colonization through high affinity interactions with the cornified envelope in the anterior nares. However, the role of ClfB during skin and soft tissue infection (SSTI) has never been investigated. This study reveals a novel role for ClfB during SSTIs. ClfB is crucial in determining the abscess structure and bacterial burden early in infection and this is dependent upon a specific interaction with the ligand loricrin which is expressed within the abscess tissue. Targeting ClfB using a model vaccine that induced both protective humoral and cellular responses, leads to protection during S. aureus skin infection. This study therefore identifies ClfB as an important antigen for future SSTI vaccines. Staphylococcus aureus is the leading cause of skin and soft tissue infections (SSTIs), the treatment of which is becoming increasingly difficult due to antibiotic resistance. An anti-S. aureus vaccine offers a potential solution, but a better understanding of how S. aureus causes pathology during SSTI is required to identify effective vaccine targets. Here, we identify an important virulence determinant during S. aureus SSTI. Clumping factor B (ClfB), a surface protein expressed by S. aureus is shown to promote skin abscess formation by binding to the host protein loricrin. Targeting ClfB using a model vaccine conferred significant protection during S. aureus SSTI. In this study, we uncover an entirely novel mechanism by which S. aureus forms abscesses during skin infection, identifying an important therapeutic target for treating S. aureus SSTI.
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Evolution of Daptomycin Resistance in Coagulase-Negative Staphylococci Involves Mutations of the Essential Two-Component Regulator WalKR. Antimicrob Agents Chemother 2019; 63:AAC.01926-18. [PMID: 30617095 DOI: 10.1128/aac.01926-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/02/2019] [Indexed: 01/19/2023] Open
Abstract
Coagulase-negative staphylococci (CoNS) represent one of the major causes of health care- and medical device-associated infections. Emerging antimicrobial resistance has complicated the treatment of systemic infections caused by CoNS. Here, we describe the prevalence of antimicrobial resistance in clinical CoNS strains from a tertiary care hospital over a 4-year period, and we observed a significant increase in resistance to daptomycin. Notably, Staphylococcus capitis accounted for the majority of these daptomycin-resistant (DAP-R) CoNS. To further investigate the mechanisms of daptomycin resistance in CoNS, daptomycin-susceptible clinical strains of S. capitis and Staphylococcus epidermidis underwent in vitro daptomycin exposure to generate DAP-R CoNS mutants. Unlike that seen with Staphylococcus aureus, alteration of cell surface charge was not observed in the DAP-R CoNS strains, but biofilm formation was compromised. Whole-genome sequencing analysis of the DAP-R CoNS strains identified single nucleotide polymorphisms (SNPs) in walKR, the essential two-component regulatory system controlling cell wall biogenesis. PCR and sequencing of walK and walR from 17 DAP-R CoNS clinical isolates identified seven nonsynonymous mutations. The results were confirmed by the recreation of the walK SNP in S. epidermidis, which resulted in reduced susceptibility to daptomycin and vancomycin. This study highlights the significance of CoNS in evolving daptomycin resistance and showed that walKR is shared among the staphylococcal species and is involved in antibiotic resistance development. Notably, we did not observe mutations in genes responsible for phospholipid biosynthesis or an altered cell surface charge, suggesting that reduced daptomycin susceptibility in CoNS may emerge in a fashion distinct from that in S. aureus.
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Głowacka-Rutkowska A, Gozdek A, Empel J, Gawor J, Żuchniewicz K, Kozińska A, Dębski J, Gromadka R, Łobocka M. The Ability of Lytic Staphylococcal Podovirus vB_SauP_phiAGO1.3 to Coexist in Equilibrium With Its Host Facilitates the Selection of Host Mutants of Attenuated Virulence but Does Not Preclude the Phage Antistaphylococcal Activity in a Nematode Infection Model. Front Microbiol 2019; 9:3227. [PMID: 30713528 PMCID: PMC6346686 DOI: 10.3389/fmicb.2018.03227] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phage vB_SauP_phiAGO1.3 (phiAGO1.3) is a polyvalent Staphylococcus lytic podovirus with a 17.6-kb genome (Gozdek et al., 2018). It can infect most of the Staphylococcus aureus human isolates of dominant clonal complexes. We show that a major factor contributing to the wide host range of phiAGO1.3 is a lack or sparcity of target sites for certain restriction-modification systems of types I and II in its genome. Phage phiAGO1.3 requires for adsorption β-O-GlcNAcylated cell wall teichoic acid, which is also essential for the expression of methicillin resistance. Under certain conditions an exposure of S. aureus to phiAGO1.3 can lead to the establishment of a mixed population in which the bacteria and phages remain in equilibrium over multiple generations. This is reminiscent of the so called phage carrier state enabling the co-existence of phage-resistant and phage-sensitive cells supporting a continuous growth of the bacterial and phage populations. The stable co-existence of bacteria and phage favors the emergence of phage-resistant variants of the bacterium. All phiAGO1.3-resistant cells isolated from the phage-carrier-state cultures contained a mutation inactivating the two-component regulatory system ArlRS, essential for efficient expression of numerous S. aureus virulence-associated traits. Moreover, the mutants were unaffected in their susceptibility to infection with an unrelated, polyvalent S. aureus phage of the genus Kayvirus. The ability of phiAGO1.3 to establish phage-carrier-state cultures did not preclude its antistaphylococcal activity in vivo in an S. aureus nematode infection model. Taken together our results suggest that phiAGO1.3 could be suitable for the therapeutic application in humans and animals, alone or in cocktails with Kayvirus phages. It might be especially useful in the treatment of infections with the majority of methicillin-resistant S. aureus strains.
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Affiliation(s)
- Aleksandra Głowacka-Rutkowska
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Gozdek
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna Empel
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, Warsaw, Poland
| | - Jan Gawor
- Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Karolina Żuchniewicz
- Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Aleksandra Kozińska
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, Warsaw, Poland
| | - Janusz Dębski
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Robert Gromadka
- Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Małgorzata Łobocka
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Autonomous Department of Microbial Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Warsaw, Poland
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126
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Acquired Nisin Resistance in Staphylococcus aureus Involves Constitutive Activation of an Intrinsic Peptide Antibiotic Detoxification Module. mSphere 2018; 3:3/6/e00633-18. [PMID: 30541781 PMCID: PMC6291627 DOI: 10.1128/mspheredirect.00633-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter. Resistance to the lantibiotic nisin (NIS) arises readily in Staphylococcus aureus as a consequence of mutations in the nsaS gene, which encodes the sensor kinase of the NsaRS two-component regulatory system. Here we present a series of studies to establish how these mutational changes result in reduced NIS susceptibility. Comparative transcriptomic analysis revealed upregulation of the NsaRS regulon in a NIS-resistant mutant of S. aureus versus its otherwise-isogenic progenitor, indicating that NIS resistance mutations prompt gain-of-function in NsaS. Two putative ABC transporters (BraDE and VraDE) encoded within the NsaRS regulon that have been reported to provide a degree of intrinsic protection against NIS were shown to be responsible for acquired NIS resistance; as is the case for intrinsic NIS resistance, NIS detoxification was ultimately mediated by VraDE, with BraDE participating in the signaling cascade underlying VraDE expression. Our study revealed new features of this signal transduction pathway, including that BraDE (but not VraDE) physically interacts with NsaRS. Furthermore, while BraDE has been shown to sense stimuli and signal to NsaS in a process that is contingent upon ATP hydrolysis, we established that this protein complex is also essential for onward transduction of the signal from NsaS through energy-independent means. NIS resistance in S. aureus therefore joins the small number of documented examples in which acquired antimicrobial resistance results from the unmasking of an intrinsic detoxification mechanism through gain-of-function mutation in a regulatory circuit. IMPORTANCE NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter.
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127
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Inactivation of the Monofunctional Peptidoglycan Glycosyltransferase SgtB Allows Staphylococcus aureus To Survive in the Absence of Lipoteichoic Acid. J Bacteriol 2018; 201:JB.00574-18. [PMID: 30322854 PMCID: PMC6287468 DOI: 10.1128/jb.00574-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 12/29/2022] Open
Abstract
The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis. The cell wall of Staphylococcus aureus is composed of peptidoglycan and the anionic polymers lipoteichoic acid (LTA) and wall teichoic acid. LTA is required for growth and normal cell morphology in S. aureus. Strains lacking LTA are usually viable only when grown under osmotically stabilizing conditions or after the acquisition of compensatory mutations. LTA-negative suppressor strains with inactivating mutations in gdpP, which resulted in increased intracellular c-di-AMP levels, were described previously. Here, we sought to identify factors other than c-di-AMP that allow S. aureus to survive without LTA. LTA-negative strains able to grow in unsupplemented medium were obtained and found to contain mutations in sgtB, mazE, clpX, or vraT. The growth improvement through mutations in mazE and sgtB was confirmed by complementation analysis. We also showed that an S. aureussgtB transposon mutant, with the monofunctional peptidoglycan glycosyltransferase SgtB inactivated, displayed a 4-fold increase in the MIC of oxacillin, suggesting that alterations in the peptidoglycan structure could help bacteria compensate for the lack of LTA. Muropeptide analysis of peptidoglycans isolated from a wild-type strain and sgtB mutant strain did not reveal any sizable alterations in the peptidoglycan structure. In contrast, the peptidoglycan isolated from an LTA-negative ltaS mutant strain showed a significant reduction in the fraction of highly cross-linked peptidoglycan, which was partially rescued in the sgtB ltaS double mutant suppressor strain. Taken together, these data point toward an important function of LTA in cell wall integrity through its necessity for proper peptidoglycan assembly. IMPORTANCE The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis.
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128
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Wu Z, Zhang L, Qiao D, Xue H, Zhao X. Functional Analyses of Cassette Chromosome Recombinase C2 (CcrC2) and Its Use in Eliminating Methicillin Resistance by Combining CRISPR-Cas9. ACS Synth Biol 2018; 7:2590-2599. [PMID: 30278126 DOI: 10.1021/acssynbio.8b00261] [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] [Indexed: 11/29/2022]
Abstract
Worldwide occurrence of methicillin-resistant Staphylococcus aureus (MRSA) poses enormous challenges for both communities and health care settings. Cassette chromosome recombinases (Ccr) specifically perform excision and acquisition of a staphylococcal cassette chromosome mec (SCC mec) in staphylococci and are responsible for the spread of methicillin resistance. This study explored the roles of CcrC2, a recently discovered Ccr, in the horizontal transfer of SCC mec and developed a potential means to control the spread of methicillin resistance. Knockout of CcrC2 completely aborted the excision of SCC mec, while overexpression of CcrC2 partially removed the SCC mec from the genome and transformed methicillin-resistant Staphylococcus aureus (MRSA) into methicillin-susceptible Staphylococcus aureus (MSSA). Moreover, two nucleotide residues (G5C6) in the direct repeat sequence within an att site were found to be critical for excision and acquisition efficiencies. To block the horizontal transfer of methicillin resistance, a SCC mec killer system was developed by combining the CcrC2-mediated SCC mec excision and the mecA-targeting CRISPR-Cas9 machinery. The SCC mec killer transformed MRSA to MSSA and disrupted the mecA-carrying SCC mec intermediate, thereby eliminating methicillin resistance determinant mecA gene inside a MRSA cell and blocking the horizontal transfer of SCC mec. The SCC mec killer was versatile for efficiently removing multiple types of SCC mec elements. It is envisioned that this approach could offer a new means to control the spread of methicillin resistance.
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Affiliation(s)
- Zhaowei Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, People’s Republic of China
| | - Limin Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, People’s Republic of China
| | - Dandan Qiao
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, People’s Republic of China
| | - Huping Xue
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, People’s Republic of China
| | - Xin Zhao
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, People’s Republic of China
- Department of Animal Science, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
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129
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Richards AC, O'Shea M, Beard PM, Goncheva MI, Tuffs SW, Fitzgerald JR, Lengeling A. Staphylococcus pseudintermedius Surface Protein L (SpsL) Is Required for Abscess Formation in a Murine Model of Cutaneous Infection. Infect Immun 2018; 86:IAI.00631-18. [PMID: 30181348 PMCID: PMC6204706 DOI: 10.1128/iai.00631-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus pseudintermedius is the leading cause of pyoderma in dogs and is often associated with recurrent skin infections that require prolonged antibiotic therapy. High levels of antibiotic use have led to multidrug resistance, including the emergence of epidemic methicillin-resistant clones. Our understanding of the pathogenesis of S. pseudintermedius skin infection is very limited, and the identification of the key host-pathogen interactions underpinning infection could lead to the design of novel therapeutic or vaccine-based approaches for controlling disease. Here, we employ a novel murine cutaneous-infection model of S. pseudintermedius and investigate the role of the two cell wall-associated proteins (SpsD and SpsL) in skin disease pathogenesis. Experimental infection with wild-type S. pseudintermedius strain ED99 or a gene-deletion derivative deficient in expression of SpsD led to a focal accumulation of neutrophils and necrotic debris in the dermis and deeper tissues of the skin characteristic of a classical cutaneous abscess. In contrast, mice infected with mutants deficient in SpsL or both SpsD and SpsL developed larger cutaneous lesions with distinct histopathological features of regionally extensive cellulitis rather than focal abscessation. Furthermore, comparison of the bacterial loads in S. pseudintermedius-induced cutaneous lesions revealed a significantly increased burden of bacteria in the mice infected with SpsL-deficient mutants. These findings reveal a key role for SpsL in murine skin abscess formation and highlight a novel function for a bacterial surface protein in determining the clinical outcome and pathology of infection caused by a major canine pathogen.
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Affiliation(s)
- Amy C Richards
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Marie O'Shea
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Philippa M Beard
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mariya I Goncheva
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephen W Tuffs
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - J Ross Fitzgerald
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Andreas Lengeling
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
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130
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Stamsås GA, Myrbråten IS, Straume D, Salehian Z, Veening JW, Håvarstein LS, Kjos M. CozEa and CozEb play overlapping and essential roles in controlling cell division in Staphylococcus aureus. Mol Microbiol 2018; 109:615-632. [PMID: 29884993 DOI: 10.1111/mmi.13999] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2018] [Indexed: 01/07/2023]
Abstract
Staphylococcus aureus needs to control the position and timing of cell division and cell wall synthesis to maintain its spherical shape. We identified two membrane proteins, named CozEa and CozEb, which together are important for proper cell division in S. aureus. CozEa and CozEb are homologs of the cell elongation regulator CozESpn of Streptococcus pneumoniae. While cozEa and cozEb were not essential individually, the ΔcozEaΔcozEb double mutant was lethal. To study the functions of cozEa and cozEb, we constructed a CRISPR interference (CRISPRi) system for S. aureus, allowing transcriptional knockdown of essential genes. CRISPRi knockdown of cozEa in the ΔcozEb strain (and vice versa) causes cell morphological defects and aberrant nucleoid staining, showing that cozEa and cozEb have overlapping functions and are important for normal cell division. We found that CozEa and CozEb interact with and possibly influence localization of the cell division protein EzrA. Furthermore, the CozE-EzrA interaction is conserved in S. pneumoniae, and cell division is mislocalized in cozESpn -depleted S. pneumoniae cells. Together, our results show that CozE proteins mediate control of cell division in S. aureus and S. pneumoniae, likely via interactions with key cell division proteins such as EzrA.
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Affiliation(s)
- Gro Anita Stamsås
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Ine Storaker Myrbråten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Daniel Straume
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Zhian Salehian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Leiv Sigve Håvarstein
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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131
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Guérillot R, Li L, Baines S, Howden B, Schultz MB, Seemann T, Monk I, Pidot SJ, Gao W, Giulieri S, Gonçalves da Silva A, D’Agata A, Tomita T, Peleg AY, Stinear TP, Howden BP. Comprehensive antibiotic-linked mutation assessment by resistance mutation sequencing (RM-seq). Genome Med 2018; 10:63. [PMID: 30165908 PMCID: PMC6117896 DOI: 10.1186/s13073-018-0572-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 07/24/2018] [Indexed: 12/15/2022] Open
Abstract
Mutation acquisition is a major mechanism of bacterial antibiotic resistance that remains insufficiently characterised. Here we present RM-seq, a new amplicon-based deep sequencing workflow based on a molecular barcoding technique adapted from Low Error Amplicon sequencing (LEA-seq). RM-seq allows detection and functional assessment of mutational resistance at high throughput from mixed bacterial populations. The sensitive detection of very low-frequency resistant sub-populations permits characterisation of antibiotic-linked mutational repertoires in vitro and detection of rare resistant populations during infections. Accurate quantification of resistance mutations enables phenotypic screening of mutations conferring pleiotropic phenotypes such as in vivo persistence, collateral sensitivity or cross-resistance. RM-seq will facilitate comprehensive detection, characterisation and surveillance of resistant bacterial populations ( https://github.com/rguerillot/RM-seq ).
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Affiliation(s)
- Romain Guérillot
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Lucy Li
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Sarah Baines
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Brian Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Mark B. Schultz
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Torsten Seemann
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, Victoria Australia
| | - Ian Monk
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Wei Gao
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Stefano Giulieri
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anders Gonçalves da Silva
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anthony D’Agata
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Takehiro Tomita
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anton Y. Peleg
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria Australia
- Infection and Immunity Theme, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Infectious Diseases Department, Austin Health, Heidelberg, Victoria Australia
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132
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Gannoun-Zaki L, Pätzold L, Huc-Brandt S, Baronian G, Elhawy MI, Gaupp R, Martin M, Blanc-Potard AB, Letourneur F, Bischoff M, Molle V. PtpA, a secreted tyrosine phosphatase from Staphylococcus aureus, contributes to virulence and interacts with coronin-1A during infection. J Biol Chem 2018; 293:15569-15580. [PMID: 30131335 DOI: 10.1074/jbc.ra118.003555] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/16/2018] [Indexed: 11/06/2022] Open
Abstract
Secretion of bacterial signaling proteins and adaptation to the host, especially during infection, are processes that are often linked in pathogenic bacteria. The human pathogen Staphylococcus aureus is equipped with a large arsenal of immune-modulating factors, allowing it to either subvert the host immune response or to create permissive niches for its survival. Recently, we showed that one of the low-molecular-weight protein tyrosine phosphatases produced by S. aureus, PtpA, is secreted during growth. Here, we report that deletion of ptpA in S. aureus affects intramacrophage survival and infectivity. We also observed that PtpA is secreted during macrophage infection. Immunoprecipitation assays identified several host proteins as putative intracellular binding partners for PtpA, including coronin-1A, a cytoskeleton-associated protein that is implicated in a variety of cellular processes. Of note, we demonstrated that coronin-1A is phosphorylated on tyrosine residues upon S. aureus infection and that its phosphorylation profile is linked to PtpA expression. Our results confirm that PtpA has a critical role during infection as a bacterial effector protein that counteracts host defenses.
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Affiliation(s)
- Laila Gannoun-Zaki
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Linda Pätzold
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Sylvaine Huc-Brandt
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Grégory Baronian
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Mohamed Ibrahem Elhawy
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Rosmarie Gaupp
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Marianne Martin
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Anne-Béatrice Blanc-Potard
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - François Letourneur
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Markus Bischoff
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Virginie Molle
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
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133
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Rapidly moving new bacteria to model-organism status. Curr Opin Biotechnol 2018; 51:116-122. [DOI: 10.1016/j.copbio.2017.12.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/11/2017] [Indexed: 11/23/2022]
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134
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Chen P, Karna SLR, Leung KP. Creation of deletion and insertion clonal complex 8 Staphylococcus aureus mutants using a common cloning vector. J Microbiol Methods 2018; 149:101-105. [PMID: 29758246 DOI: 10.1016/j.mimet.2018.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/07/2018] [Accepted: 05/11/2018] [Indexed: 10/16/2022]
Abstract
Deletion and insertion clonal complex 8 Staphylococcus aureus mutants were created without using intermediate host S. aureus RN4220 or temperature-sensitive shuttle vectors. These mutants were created using a common cloning vector by passing the constructs through a modification host and recovering the electroporated cells in a large volume of medium.
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Affiliation(s)
- Ping Chen
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, US Army Institute of Surgical Research, JBSA Fort Sam, Houston, TX 78234, United States
| | - S L Rajasekhar Karna
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, US Army Institute of Surgical Research, JBSA Fort Sam, Houston, TX 78234, United States
| | - Kai P Leung
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, US Army Institute of Surgical Research, JBSA Fort Sam, Houston, TX 78234, United States.
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135
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Zeden MS, Schuster CF, Bowman L, Zhong Q, Williams HD, Gründling A. Cyclic di-adenosine monophosphate (c-di-AMP) is required for osmotic regulation in Staphylococcus aureus but dispensable for viability in anaerobic conditions. J Biol Chem 2018; 293:3180-3200. [PMID: 29326168 PMCID: PMC5836111 DOI: 10.1074/jbc.m117.818716] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/03/2018] [Indexed: 01/15/2023] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus However, the exact role of this molecule has not been identified. dacA, the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition. Here, we report that an S. aureus dacA mutant can be generated in chemically defined medium. Consistent with previous findings, this mutant had a severe growth defect when cultured in rich medium. Using this growth defect in rich medium, we selected for suppressor strains with improved growth to identify c-di-AMP-requiring pathways. Mutations bypassing the essentiality of dacA were identified in alsT and opuD, encoding a predicted amino acid and osmolyte transporter, the latter of which we show here to be the main glycine betaine-uptake system in S. aureus. Inactivation of these transporters likely prevents the excessive osmolyte and amino acid accumulation in the cell, providing further evidence for a key role of c-di-AMP in osmotic regulation. Suppressor mutations were also obtained in hepS, hemB, ctaA, and qoxB, coding proteins required for respiration. Furthermore, we show that dacA is dispensable for growth in anaerobic conditions. Together, these findings reveal an essential role for the c-di-AMP signaling network in aerobic, but not anaerobic, respiration in S. aureus.
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Affiliation(s)
- Merve S Zeden
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Christopher F Schuster
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Lisa Bowman
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Qiyun Zhong
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Huw D Williams
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
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136
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Gu T, Zhao S, Pi Y, Chen W, Chen C, Liu Q, Li M, Han D, Ji Q. Highly efficient base editing in Staphylococcus aureus using an engineered CRISPR RNA-guided cytidine deaminase. Chem Sci 2018; 9:3248-3253. [PMID: 29780457 PMCID: PMC5932532 DOI: 10.1039/c8sc00637g] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/20/2018] [Indexed: 01/17/2023] Open
Abstract
The base editor pnCasSA-BEC enables highly efficient base editing in Staphylococcus aureus.
Novel therapeutic means against Staphylococcus aureus infections are urgently needed due to the emergence of drug-resistant S. aureus. We report the development of a CRISPR RNA-guided cytidine deaminase (pnCasSA–BEC), enabling highly efficient gene inactivation and point mutations in S. aureus. We engineered a fusion of a Cas9 nickase (Cas9D10A) and a cytidine deaminase (APOBEC1) that can be guided to a target genomic locus for gene inactivation via generating a premature stop codon. The pnCasSA–BEC system nicks the non-edited strand of the genomic DNA, directly catalyzes the conversion of cytidine (C) to uridine (U), and relies on DNA replication to achieve C → T (G → A) conversion without using donor repair templates. The development of the base-editing system will dramatically accelerate drug-target exploration in S. aureus and provides critical insights into the development of base-editing tools in other microbes.
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Affiliation(s)
- Tongnian Gu
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China .
| | - Siqi Zhao
- Key Laboratory of Genomic and Precision Medicine , Beijing Institute of Genomics , Chinese Academy of Sciences , Beijing 100101 , China . .,College of Future Technology , Sino-Danish College , University of Chinese Academy of Science , Beijing 100049 , China
| | - Yishuang Pi
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China .
| | - Weizhong Chen
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China .
| | - Chuanyuan Chen
- Key Laboratory of Genomic and Precision Medicine , Beijing Institute of Genomics , Chinese Academy of Sciences , Beijing 100101 , China . .,College of Future Technology , Sino-Danish College , University of Chinese Academy of Science , Beijing 100049 , China
| | - Qian Liu
- Department of Laboratory Medicine , Ren Ji Hospital , School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Min Li
- Department of Laboratory Medicine , Ren Ji Hospital , School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China
| | - Dali Han
- Key Laboratory of Genomic and Precision Medicine , Beijing Institute of Genomics , Chinese Academy of Sciences , Beijing 100101 , China . .,College of Future Technology , Sino-Danish College , University of Chinese Academy of Science , Beijing 100049 , China
| | - Quanjiang Ji
- School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China .
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137
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Bojer MS, Lindemose S, Vestergaard M, Ingmer H. Quorum Sensing-Regulated Phenol-Soluble Modulins Limit Persister Cell Populations in Staphylococcus aureus. Front Microbiol 2018; 9:255. [PMID: 29515541 PMCID: PMC5826201 DOI: 10.3389/fmicb.2018.00255] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/31/2018] [Indexed: 11/15/2022] Open
Abstract
Incomplete killing of bacterial pathogens by antibiotics is an underlying cause of treatment failure and accompanying complications. Among those avoiding chemotherapy are persisters being individual cells in a population that for extended periods of time survive high antibiotic concentrations proposedly by being in a quiescent state refractory to antibiotic killing. While investigating the human pathogen Staphylococcus aureus and the influence of growth phase on persister formation, we noted that spent supernatants of stationary phase cultures of S. aureus or S. epidermidis, but not of distantly related bacteria, significantly reduced the persister cell frequency upon ciprofloxacin challenge when added to exponentially growing and stationary phase S. aureus cells. Curiously, the persister reducing activity of S. aureus supernatants was also effective against persisters formed by either S. carnosus or Listeria monocytogenes. The persister reducing component, which resisted heat but not proteases and was produced in the late growth phase in an agr quorum-sensing dependent manner, was identified to be the phenol-soluble modulin (PSM) toxins. S. aureus express several PSMs, each with distinct cytolytic and antimicrobial properties; however, the persister reducing activity was specifically linked to synthesis of the PSMα family. Correspondingly, a high-persister phenotype of a PSMα mutant was observed upon fluoroquinolone or aminoglycoside challenge, demonstrating that the persister reducing activity of PSMs can be endogenously synthesized or extrinsically added. Given that PSMs have been associated with lytic activity against bacterial membranes we propose that PSM toxins increase the susceptibility of persister cells to killing by intracellularly acting antibiotics and that chronic and re-occurring infections with quorum sensing, agr negative mutants may be difficult to treat with antibiotics because of persister cells formed in the absence of PSM toxins.
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Affiliation(s)
- Martin S. Bojer
- Faculty of Health and Medical Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Centre for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Søren Lindemose
- Centre for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Martin Vestergaard
- Faculty of Health and Medical Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hanne Ingmer
- Faculty of Health and Medical Sciences, Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Centre for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
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138
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Efficient and Scalable Precision Genome Editing in Staphylococcus aureus through Conditional Recombineering and CRISPR/Cas9-Mediated Counterselection. mBio 2018; 9:mBio.00067-18. [PMID: 29463653 PMCID: PMC5821094 DOI: 10.1128/mbio.00067-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Staphylococcus aureus is an important human pathogen, but studies of the organism have suffered from the lack of a robust tool set for its genetic and genomic manipulation. Here we report the development of a system for the facile and high-throughput genomic engineering of S. aureus using single-stranded DNA (ssDNA) oligonucleotide recombineering coupled with clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-mediated counterselection. We identify recombinase EF2132, derived from Enterococcus faecalis, as being capable of integrating single-stranded DNA oligonucleotides into the S. aureus genome. We found that EF2132 can readily mediate recombineering across multiple characterized strains (3 of 3 tested) and primary clinical isolates (6 of 6 tested), typically yielding thousands of recombinants per transformation. Surprisingly, we also found that some S. aureus strains are naturally recombinogenic at measurable frequencies when oligonucleotides are introduced by electroporation, even without exogenous recombinase expression. We construct a temperature-sensitive, two-vector system which enables conditional recombineering and CRISPR/Cas9-mediated counterselection in S. aureus without permanently introducing exogenous genetic material or unintended genetic lesions. We demonstrate the ability of this system to efficiently and precisely engineer point mutations and large single-gene deletions in the S. aureus genome and to yield highly enriched populations of engineered recombinants even in the absence of an externally selectable phenotype. By virtue of utilizing inexpensive, commercially synthesized synthetic DNA oligonucleotides as substrates for recombineering and counterselection, this system provides a scalable, versatile, precise, inexpensive, and generally useful tool for producing isogenic strains in S. aureus which will enable the high-throughput functional assessment of genome variation and gene function across multiple strain backgrounds. Engineering genetic changes in bacteria is critical to understanding the function of particular genes or mutations but is currently a laborious and technically challenging process to perform for the important human pathogen Staphylococcus aureus. In an effort to develop methods which are rapid, easy, scalable, versatile, and inexpensive, here we describe a system for incorporating synthetic, mutagenic DNA molecules into the S. aureus genome and for eliminating cells that lack the engineered mutation. This method allows efficient, precise, and high-throughput genetic engineering of S. aureus strains and will facilitate studies seeking to address a variety of issues about the function of particular genes and specific mutations.
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139
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Convergent Evolution Driven by Rifampin Exacerbates the Global Burden of Drug-Resistant Staphylococcus aureus. mSphere 2018; 3:mSphere00550-17. [PMID: 29404415 PMCID: PMC5784246 DOI: 10.1128/msphere.00550-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/23/2017] [Indexed: 11/20/2022] Open
Abstract
Mutations in the beta-subunit of bacterial RNA polymerase (RpoB) cause resistance to rifampin (Rifr), a critical antibiotic for treatment of multidrug-resistant Staphylococcus aureus. In vitro studies have shown that RpoB mutations confer decreased susceptibility to other antibiotics, but the clinical relevance is unknown. Here, by analyzing 7,099 S. aureus genomes, we demonstrate that the most prevalent RpoB mutations promote clinically relevant phenotypic plasticity resulting in the emergence of stable S. aureus lineages, associated with increased risk of therapeutic failure through generation of small-colony variants (SCVs) and coresistance to last-line antimicrobial agents. We found eight RpoB mutations that accounted for 93% (469/505) of the total number of Rifr mutations. The most frequently selected amino acid substitutions affecting residue 481 (H481N/Y) were associated with worldwide expansions of Rifr clones spanning decades. Recreating the H481N/Y mutations confirmed no impact on S. aureus growth, but the H481N mutation promoted the emergence of a subpopulation of stable Rifr SCVs with reduced susceptibility to vancomycin and daptomycin. Recreating the other frequent RpoB mutations showed similar impacts on resistance to these last-line agents. We found that 86% of all Rifr isolates in our global sample carried the mutations promoting cross-resistance to vancomycin and 52% to both vancomycin and daptomycin. As four of the most frequent RpoB mutations confer only low-level Rifr, equal to or below some international breakpoints, we recommend decreasing these breakpoints and reconsidering the appropriate use of rifampin to reduce the fixation and spread of these clinically deleterious mutations. IMPORTANCE Increasing antibiotic resistance in the major human pathogen Staphylococcus aureus is threatening the ability to treat patients with these infections. Recent laboratory studies suggest that mutations in the gene commonly associated with rifampin resistance may also impact susceptibility to other last-line antibiotics in S. aureus; however, the overall frequency and clinical impact of these mutations are unknown. By mining a global collection of clinical S. aureus genomes and by mutagenesis experiments, this work reveals that common rifampin-induced rpoB mutations promote phenotypic plasticity that has led to the global emergence of stable, multidrug-resistant S. aureus lineages that are associated with increased risk of therapeutic failure through coresistance to other last-line antimicrobials. We recommend decreasing susceptibility breakpoints for rifampin to allow phenotypic detection of critical rpoB mutations conferring low resistance to rifampin and reconsidering the appropriate use of rifampin to reduce the fixation and spread of these deleterious mutations globally.
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140
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Xue H, Wu Z, Qiao D, Tong C, Zhao X. Global acquisition of genetic material from different bacteria into the staphylococcal cassette chromosome elements of a Staphylococcus epidermidis isolate. Int J Antimicrob Agents 2017; 50:581-587. [DOI: 10.1016/j.ijantimicag.2017.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 06/24/2017] [Indexed: 10/19/2022]
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141
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Inhibition of the ATP Synthase Eliminates the Intrinsic Resistance of Staphylococcus aureus towards Polymyxins. mBio 2017; 8:mBio.01114-17. [PMID: 28874470 PMCID: PMC5587909 DOI: 10.1128/mbio.01114-17] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Staphylococcus aureus is intrinsically resistant to polymyxins (polymyxin B and colistin), an important class of cationic antimicrobial peptides used in treatment of Gram-negative bacterial infections. To understand the mechanisms underlying intrinsic polymyxin resistance in S. aureus, we screened the Nebraska Transposon Mutant Library established in S. aureus strain JE2 for increased susceptibility to polymyxin B. Nineteen mutants displayed at least 2-fold reductions in MIC, while the greatest reductions (8-fold) were observed for mutants with inactivation of either graS, graR, vraF, or vraG or the subunits of the ATP synthase (atpA, atpB, atpG, or atpH), which during respiration is the main source of energy. Inactivation of atpA also conferred hypersusceptibility to colistin and the aminoglycoside gentamicin, whereas susceptibilities to nisin, gallidermin, bacitracin, vancomycin, ciprofloxacin, linezolid, daptomycin, and oxacillin were unchanged. ATP synthase activity is known to be inhibited by oligomycin A, and the presence of this compound increased polymyxin B-mediated killing of S. aureus Our results demonstrate that the ATP synthase contributes to intrinsic resistance of S. aureus towards polymyxins and that inhibition of the ATP synthase sensitizes S. aureus to this group of compounds. These findings show that by modulation of bacterial metabolism, new classes of antibiotics may show efficacy against pathogens towards which they were previously considered inapplicable. In light of the need for new treatment options for infections with serious pathogens like S. aureus, this approach may pave the way for novel applications of existing antibiotics.IMPORTANCE Bacterial pathogens that cause disease in humans remain a serious threat to public health, and antibiotics are still our primary weapon in treating bacterial diseases. The ability to eradicate bacterial infections is critically challenged by development of resistance to all clinically available antibiotics. Polymyxins constitute an important class of antibiotics for treatment of infections caused by Gram-negative pathogens, whereas Gram-positive bacteria remain largely insusceptible towards class of antibiotics. Here we performed a whole-genome screen among nonessential genes for polymyxin intrinsic resistance determinants in Staphylococcus aureus We found that the ATP synthase is important for polymyxin susceptibility and that inhibition of the ATP synthase sensitizes S. aureus towards polymyxins. Our study provides novel insights into the mechanisms that limit polymyxin activity against S. aureus and provides valuable targets for inhibitors to potentially enable the use of polymyxins against S. aureus and other Gram-positive pathogens.
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142
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Cooper LP, Roberts GA, White JH, Luyten YA, Bower EKM, Morgan RD, Roberts RJ, Lindsay JA, Dryden DTF. DNA target recognition domains in the Type I restriction and modification systems of Staphylococcus aureus. Nucleic Acids Res 2017; 45:3395-3406. [PMID: 28180279 PMCID: PMC5399793 DOI: 10.1093/nar/gkx067] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/03/2017] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus displays a clonal population structure in which horizontal gene transfer between different lineages is extremely rare. This is due, in part, to the presence of a Type I DNA restriction–modification (RM) system given the generic name of Sau1, which maintains different patterns of methylation on specific target sequences on the genomes of different lineages. We have determined the target sequences recognized by the Sau1 Type I RM systems present in a wide range of the most prevalent S. aureus lineages and assigned the sequences recognized to particular target recognition domains within the RM enzymes. We used a range of biochemical assays on purified enzymes and single molecule real-time sequencing on genomic DNA to determine these target sequences and their patterns of methylation. Knowledge of the main target sequences for Sau1 will facilitate the synthesis of new vectors for transformation of the most prevalent lineages of this ‘untransformable’ bacterium.
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Affiliation(s)
- Laurie P Cooper
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3FJ, UK
| | - Gareth A Roberts
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3FJ, UK
| | - John H White
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3FJ, UK
| | - Yvette A Luyten
- New England Biolabs, 240 County Road, Ipswich, MA 01938-2723, USA
| | - Edward K M Bower
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3FJ, UK
| | - Richard D Morgan
- New England Biolabs, 240 County Road, Ipswich, MA 01938-2723, USA
| | | | - Jodi A Lindsay
- Institute of Infection and Immunity, St George's, University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - David T F Dryden
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
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143
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Bypassing the Restriction System To Improve Transformation of Staphylococcus epidermidis. J Bacteriol 2017; 199:JB.00271-17. [PMID: 28559294 DOI: 10.1128/jb.00271-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/21/2017] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus epidermidis is the leading cause of infections on indwelling medical devices worldwide. Intrinsic antibiotic resistance and vigorous biofilm production have rendered these infections difficult to treat and, in some cases, require the removal of the offending medical prosthesis. With the exception of two widely passaged isolates, RP62A and 1457, the pathogenesis of infections caused by clinical S. epidermidis strains is poorly understood due to the strong genetic barrier that precludes the efficient transformation of foreign DNA into clinical isolates. The difficulty in transforming clinical S. epidermidis isolates is primarily due to the type I and IV restriction-modification systems, which act as genetic barriers. Here, we show that efficient plasmid transformation of clinical S. epidermidis isolates from clonal complexes 2, 10, and 89 can be realized by employing a plasmid artificial modification (PAM) in Escherichia coli DC10B containing a Δdcm mutation. This transformative technique should facilitate our ability to genetically modify clinical isolates of S. epidermidis and hence improve our understanding of their pathogenesis in human infections.IMPORTANCE Staphylococcus epidermidis is a source of considerable morbidity worldwide. The underlying mechanisms contributing to the commensal and pathogenic lifestyles of S. epidermidis are poorly understood. Genetic manipulations of clinically relevant strains of S. epidermidis are largely prohibited due to the presence of a strong restriction barrier. With the introductions of the tools presented here, genetic manipulation of clinically relevant S. epidermidis isolates has now become possible, thus improving our understanding of S. epidermidis as a pathogen.
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144
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Fleury OM, McAleer MA, Feuillie C, Formosa-Dague C, Sansevere E, Bennett DE, Towell AM, McLean WHI, Kezic S, Robinson DA, Fallon PG, Foster TJ, Dufrêne YF, Irvine AD, Geoghegan JA. Clumping Factor B Promotes Adherence of Staphylococcus aureus to Corneocytes in Atopic Dermatitis. Infect Immun 2017; 85:e00994-16. [PMID: 28373353 PMCID: PMC5442637 DOI: 10.1128/iai.00994-16] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/21/2017] [Indexed: 12/31/2022] Open
Abstract
Staphylococcus aureus skin infection is a frequent and recurrent problem in children with the common inflammatory skin disease atopic dermatitis (AD). S. aureus colonizes the skin of the majority of children with AD and exacerbates the disease. The first step during colonization and infection is bacterial adhesion to the cornified envelope of corneocytes in the outer layer, the stratum corneum. Corneocytes from AD skin are structurally different from corneocytes from normal healthy skin. The objective of this study was to identify bacterial proteins that promote the adherence of S. aureus to AD corneocytes. S. aureus strains from clonal complexes 1 and 8 were more frequently isolated from infected AD skin than from the nasal cavity of healthy children. AD strains had increased ClfB ligand binding activity compared to normal nasal carriage strains. Adherence of single S. aureus bacteria to corneocytes from AD patients ex vivo was studied using atomic force microscopy. Bacteria expressing ClfB recognized ligands distributed over the entire corneocyte surface. The ability of an isogenic ClfB-deficient mutant to adhere to AD corneocytes compared to that of its parent clonal complex 1 clinical strain was greatly reduced. ClfB from clonal complex 1 strains had a slightly higher binding affinity for its ligand than ClfB from strains from other clonal complexes. Our results provide new insights into the first step in the establishment of S. aureus colonization in AD patients. ClfB is a key adhesion molecule for the interaction of S. aureus with AD corneocytes and represents a target for intervention.
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Affiliation(s)
- Orla M Fleury
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Maeve A McAleer
- Clinical Medicine, Trinity College Dublin, Dublin, Ireland
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
- Paediatric Dermatology, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
| | - Cécile Feuillie
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Cécile Formosa-Dague
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Emily Sansevere
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Désirée E Bennett
- Epidemiology and Molecular Biology Unit, Temple Street Children's University Hospital, Dublin, Ireland
| | - Aisling M Towell
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - W H Irwin McLean
- Dermatology and Genetic Medicine, University of Dundee, Dundee, United Kingdom
| | - Sanja Kezic
- Coronel Institute of Occupational Health, Academic Medical Center, Amsterdam, The Netherlands
| | - D Ashley Robinson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Padraic G Fallon
- Clinical Medicine, Trinity College Dublin, Dublin, Ireland
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
| | - Timothy J Foster
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Yves F Dufrêne
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Wavre, Belgium
| | - Alan D Irvine
- Clinical Medicine, Trinity College Dublin, Dublin, Ireland
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
- Paediatric Dermatology, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
| | - Joan A Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
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Kpeli G, Buultjens AH, Giulieri S, Owusu-Mireku E, Aboagye SY, Baines SL, Seemann T, Bulach D, Gonçalves da Silva A, Monk IR, Howden BP, Pluschke G, Yeboah-Manu D, Stinear T. Genomic analysis of ST88 community-acquired methicillin resistant Staphylococcus aureus in Ghana. PeerJ 2017; 5:e3047. [PMID: 28265515 PMCID: PMC5333547 DOI: 10.7717/peerj.3047] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/30/2017] [Indexed: 01/11/2023] Open
Abstract
Background The emergence and evolution of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) strains in Africa is poorly understood. However, one particular MRSA lineage called ST88, appears to be rapidly establishing itself as an “African” CA-MRSA clone. In this study, we employed whole genome sequencing to provide more information on the genetic background of ST88 CA-MRSA isolates from Ghana and to describe in detail ST88 CA-MRSA isolates in comparison with other MRSA lineages worldwide. Methods We first established a complete ST88 reference genome (AUS0325) using PacBio SMRT sequencing. We then used comparative genomics to assess relatedness among 17 ST88 CA-MRSA isolates recovered from patients attending Buruli ulcer treatment centres in Ghana, three non-African ST88s and 15 other MRSA lineages. Results We show that Ghanaian ST88 forms a discrete MRSA lineage (harbouring SCCmec-IV [2B]). Gene content analysis identified five distinct genomic regions enriched among ST88 isolates compared with the other S. aureus lineages. The Ghanaian ST88 isolates had only 658 core genome SNPs and there was no correlation between phylogeny and geography, suggesting the recent spread of this clone. The lineage was also resistant to multiple classes of antibiotics including β-lactams, tetracycline and chloramphenicol. Discussion This study reveals that S. aureus ST88-IV is a recently emerging and rapidly spreading CA-MRSA clone in Ghana. The study highlights the capacity of small snapshot genomic studies to provide actionable public health information in resource limited settings. To our knowledge this is the first genomic assessment of the ST88 CA-MRSA clone.
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Affiliation(s)
- Grace Kpeli
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana; Department of Molecular Parasitology and Immunology, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Andrew H Buultjens
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Stefano Giulieri
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Evelyn Owusu-Mireku
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana , Accra , Ghana
| | - Samuel Y Aboagye
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana , Accra , Ghana
| | - Sarah L Baines
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Torsten Seemann
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia; University of Melbourne, Victorian Life Sciences Computation Initiative, Melbourne, VIC, Australia
| | - Dieter Bulach
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia; University of Melbourne, Victorian Life Sciences Computation Initiative, Melbourne, VIC, Australia
| | - Anders Gonçalves da Silva
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Ian R Monk
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia; Department of Microbiology and Immunology, Microbiological Diagnostic Unit Public Health Laboratory, Doherty Institute for Infection & Immunity, University of Melbourne, Melbourne, VIC, Australia; Department of Infectious Diseases, Austin Health, Heidelberg, VIC, Australia
| | - Gerd Pluschke
- Department of Molecular Parasitology and Immunology, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Dorothy Yeboah-Manu
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana , Accra , Ghana
| | - Timothy Stinear
- Department of Microbiology and Immunology, Doherty Applied Microbial Genomics, Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne, VIC , Australia
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Correspondence: Spontaneous secondary mutations confound analysis of the essential two-component system WalKR in Staphylococcus aureus. Nat Commun 2017; 8:14403. [PMID: 28165454 PMCID: PMC5303874 DOI: 10.1038/ncomms14403] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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147
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Bowman L, Zeden MS, Schuster CF, Kaever V, Gründling A. New Insights into the Cyclic Di-adenosine Monophosphate (c-di-AMP) Degradation Pathway and the Requirement of the Cyclic Dinucleotide for Acid Stress Resistance in Staphylococcus aureus. J Biol Chem 2016; 291:26970-26986. [PMID: 27834680 PMCID: PMC5207132 DOI: 10.1074/jbc.m116.747709] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/09/2016] [Indexed: 12/02/2022] Open
Abstract
Nucleotide signaling networks are key to facilitate alterations in gene expression, protein function, and enzyme activity in response to diverse stimuli. Cyclic di-adenosine monophosphate (c-di-AMP) is an important secondary messenger molecule produced by the human pathogen Staphylococcus aureus and is involved in regulating a number of physiological processes including potassium transport. S. aureus must ensure tight control over its cellular levels as both high levels of the dinucleotide and its absence result in a number of detrimental phenotypes. Here we show that in addition to the membrane-bound Asp-His-His and Asp-His-His-associated (DHH/DHHA1) domain-containing phosphodiesterase (PDE) GdpP, S. aureus produces a second cytoplasmic DHH/DHHA1 PDE Pde2. Although capable of hydrolyzing c-di-AMP, Pde2 preferentially converts linear 5'-phosphadenylyl-adenosine (pApA) to AMP. Using a pde2 mutant strain, pApA was detected for the first time in S. aureus, leading us to speculate that this dinucleotide may have a regulatory role under certain conditions. Moreover, pApA is involved in a feedback inhibition loop that limits GdpP-dependent c-di-AMP hydrolysis. Another protein linked to the regulation of c-di-AMP levels in bacteria is the predicted regulator protein YbbR. Here, it is shown that a ybbR mutant S. aureus strain has increased acid sensitivity that can be bypassed by the acquisition of mutations in a number of genes, including the gene coding for the diadenylate cyclase DacA. We further show that c-di-AMP levels are slightly elevated in the ybbR suppressor strains tested as compared with the wild-type strain. With this, we not only identified a new role for YbbR in acid stress resistance in S. aureus but also provide further insight into how c-di-AMP levels impact acid tolerance in this organism.
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Affiliation(s)
- Lisa Bowman
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Merve S Zeden
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Christopher F Schuster
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Volkhard Kaever
- the Research Core Unit Metabolomics, Hannover Medical School, Hannover D-306625, Germany
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
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148
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Vestergaard M, Leng B, Haaber J, Bojer MS, Vegge CS, Ingmer H. Genome-Wide Identification of Antimicrobial Intrinsic Resistance Determinants in Staphylococcus aureus. Front Microbiol 2016; 7:2018. [PMID: 28066345 PMCID: PMC5165250 DOI: 10.3389/fmicb.2016.02018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/02/2016] [Indexed: 11/24/2022] Open
Abstract
The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products that confer intrinsic resistance to antimicrobial agents may be explored for alternative antimicrobial therapies, by potentiating the efficacy of existing antimicrobials. In this study, we identified the intrinsic resistome to a broad spectrum of antimicrobials in the human pathogen, Staphylococcus aureus. We screened the Nebraska Transposon Mutant Library of 1920 single-gene inactivations in S. aureus strain JE2, for increased susceptibility to the anti-staphylococcal antimicrobials (ciprofloxacin, oxacillin, linezolid, fosfomycin, daptomycin, mupirocin, vancomycin, and gentamicin). Sixty-eight mutants were confirmed by E-test to display at least twofold increased susceptibility to one or more antimicrobial agents. The majority of the identified genes have not previously been associated with antimicrobial susceptibility in S. aureus. For example, inactivation of genes encoding for subunits of the ATP synthase, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC) of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected with the atpA mutant compared to wild type cells with gentamicin at a clinically relevant concentration. Our results demonstrate that many gene products contribute to the intrinsic antimicrobial resistance of S. aureus. Knowledge of these intrinsic resistance determinants provides alternative targets for compounds that may potentiate the efficacy of existing antimicrobial agents against this important pathogen.
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Affiliation(s)
- Martin Vestergaard
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Bingfeng Leng
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Jakob Haaber
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Martin S Bojer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Christina S Vegge
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
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Le Lam TN, Morvan C, Liu W, Bohn C, Jaszczyszyn Y, Bouloc P. Finding sRNA-associated phenotypes by competition assays: An example with Staphylococcus aureus. Methods 2016; 117:21-27. [PMID: 27916561 DOI: 10.1016/j.ymeth.2016.11.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 01/05/2023] Open
Abstract
Bacteria optimize their fitness in response to a changing environment by tight regulation of gene expression. Regulation can be controlled at both transcriptional and post-transcriptional levels via key players such as sigma factors, regulatory proteins and regulatory RNAs. The identification of phenotypes associated with gene deletions is the established method for finding gene functions but may require testing many conditions for each studied mutant. As regulatory RNAs often contribute to fine-tuning gene expression, phenotypes associated with their inactivation are often weak and difficult to detect. Nevertheless, minor phenotypes conferring modest advantages, may allow bacteria to emerge after some generations under selective pressure. A strategy employing DNA barcodes can be used to perform competition experiments between mutants and to monitor fitness associated with mutations in different growth conditions. We combined this strategy with deep sequencing to study regulatory RNAs in Staphylococcus aureus, a major opportunistic pathogen.
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Affiliation(s)
- Thao Nguyen Le Lam
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Claire Morvan
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Wenfeng Liu
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Chantal Bohn
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Yan Jaszczyszyn
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Philippe Bouloc
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
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150
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Planet PJ, Narechania A, Chen L, Mathema B, Boundy S, Archer G, Kreiswirth B. Architecture of a Species: Phylogenomics of Staphylococcus aureus. Trends Microbiol 2016; 25:153-166. [PMID: 27751626 DOI: 10.1016/j.tim.2016.09.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/07/2016] [Accepted: 09/22/2016] [Indexed: 12/11/2022]
Abstract
A deluge of whole-genome sequencing has begun to give insights into the patterns and processes of microbial evolution, but genome sequences have accrued in a haphazard manner, with biased sampling of natural variation that is driven largely by medical and epidemiological priorities. For instance, there is a strong bias for sequencing epidemic lineages of methicillin-resistant Staphylococcus aureus (MRSA) over sensitive isolates (methicillin-sensitive S. aureus: MSSA). As more diverse genomes are sequenced the emerging picture is of a highly subdivided species with a handful of relatively clonal groups (complexes) that, at any given moment, dominate in particular geographical regions. The establishment of hegemony of particular clones appears to be a dynamic process of successive waves of replacement of the previously dominant clone. Here we review the phylogenomic structure of a diverse range of S. aureus, including both MRSA and MSSA. We consider the utility of the concept of the 'core' genome and the impact of recombination and horizontal transfer. We argue that whole-genome surveillance of S. aureus populations could lead to better forecasting of antibiotic resistance and virulence of emerging clones, and a better understanding of the elusive biological factors that determine repeated strain replacement.
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Affiliation(s)
- Paul J Planet
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY, USA; Department of Pediatrics, Division of Pediatric Infectious Diseases, Children's Hospital of Philadelphia & University of Pennsylvania, Philadelphia, PA, USA.
| | - Apurva Narechania
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY, USA
| | - Liang Chen
- Public Health Research Institute Center, New Jersey Medical School, Rutgers, Newark, NJ, USA
| | - Barun Mathema
- Public Health Research Institute Center, New Jersey Medical School, Rutgers, Newark, NJ, USA; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Sam Boundy
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Gordon Archer
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Barry Kreiswirth
- Public Health Research Institute Center, New Jersey Medical School, Rutgers, Newark, NJ, USA
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