1
|
Dubey S, Siddiqui AH, Sharma M. The Impact of Fosfomycin on Gram Negative Infections: A Comprehensive Review. Indian J Microbiol 2024; 64:846-858. [PMID: 39282196 PMCID: PMC11399380 DOI: 10.1007/s12088-024-01293-8] [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: 10/16/2023] [Accepted: 04/21/2024] [Indexed: 09/18/2024] Open
Abstract
Multidrug-resistant or extended drug resistance has created havoc when it comes to patient treatment, as options are limited because of the spread of pathogens that are extensively or multidrug-resistant (MDR or XDR) and the absence of novel antibiotics that are effective against these pathogens. Physicians have therefore started using more established antibiotics such as polymyxins, tetracyclines, and aminoglycosides. Fosfomycin has just come to light as a result of the emergence of resistance to these medications since it continues to be effective against MDR and XDR bacteria that are both gram-positive and gram-negative. Fosfomycin, a bactericidal analogue of phosphoenolpyruvate that was formerly utilised as an oral medication for uncomplicated urinary tract infections, has recently attracted the interest of clinicians around the world. It may generally be a suitable therapy option for patients with highly resistant pathogenic infections, according to the advanced resistance shown by gram-negative bacteria. This review article aims to comprehensively evaluate the impact of fosfomycin on gram negative infections, highlighting its mechanism of action, pharmacokinetics, clinical efficacy, and resistance patterns.
Collapse
Affiliation(s)
- Sandeepika Dubey
- Department of Microbiology, Integral Institute of Medical Sciences Research, Integral University, Lucknow, Uttar Pradesh India
| | - Areena Hoda Siddiqui
- Department of Microbiology, Integral Institute of Medical Sciences Research, Integral University, Lucknow, Uttar Pradesh India
| | - Meenakshi Sharma
- Autonomous State Medical College, Lakhimpur Kheri, Uttar Pradesh India
| |
Collapse
|
2
|
Tossounian MA, Zhao Y, Yu BYK, Markey SA, Malanchuk O, Zhu Y, Cain A, Gout I. Low-molecular-weight thiol transferases in redox regulation and antioxidant defence. Redox Biol 2024; 71:103094. [PMID: 38479221 PMCID: PMC10950700 DOI: 10.1016/j.redox.2024.103094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/08/2024] [Accepted: 02/18/2024] [Indexed: 03/24/2024] Open
Abstract
Low-molecular-weight (LMW) thiols are produced in all living cells in different forms and concentrations. Glutathione (GSH), coenzyme A (CoA), bacillithiol (BSH), mycothiol (MSH), ergothioneine (ET) and trypanothione T(SH)2 are the main LMW thiols in eukaryotes and prokaryotes. LMW thiols serve as electron donors for thiol-dependent enzymes in redox-mediated metabolic and signaling processes, protect cellular macromolecules from oxidative and xenobiotic stress, and participate in the reduction of oxidative modifications. The level and function of LMW thiols, their oxidized disulfides and mixed disulfide conjugates in cells and tissues is tightly controlled by dedicated oxidoreductases, such as peroxiredoxins, glutaredoxins, disulfide reductases and LMW thiol transferases. This review provides the first summary of the current knowledge of structural and functional diversity of transferases for LMW thiols, including GSH, BSH, MSH and T(SH)2. Their role in maintaining redox homeostasis in single-cell and multicellular organisms is discussed, focusing in particular on the conjugation of specific thiols to exogenous and endogenous electrophiles, or oxidized protein substrates. Advances in the development of new research tools, analytical methodologies, and genetic models for the analysis of known LMW thiol transferases will expand our knowledge and understanding of their function in cell growth and survival under oxidative stress, nutrient deprivation, and during the detoxification of xenobiotics and harmful metabolites. The antioxidant function of CoA has been recently discovered and the breakthrough in defining the identity and functional characteristics of CoA S-transferase(s) is soon expected.
Collapse
Affiliation(s)
- Maria-Armineh Tossounian
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Yuhan Zhao
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Bess Yi Kun Yu
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Samuel A Markey
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Oksana Malanchuk
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom; Department of Cell Signaling, Institute of Molecular Biology and Genetics, Kyiv, 143, Ukraine
| | - Yuejia Zhu
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Amanda Cain
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Ivan Gout
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom; Department of Cell Signaling, Institute of Molecular Biology and Genetics, Kyiv, 143, Ukraine.
| |
Collapse
|
3
|
Lu W, Zhou S, Ma X, Xu N, Liu D, Zhang K, Zheng Y, Wu S. fosA11, a novel chromosomal-encoded fosfomycin resistance gene identified in Providencia rettgeri. Microbiol Spectr 2024; 12:e0254223. [PMID: 38149860 PMCID: PMC10846113 DOI: 10.1128/spectrum.02542-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/29/2023] [Indexed: 12/28/2023] Open
Abstract
This study investigated resistance genes corresponding to the fosfomycin resistance phenotype in clinical isolate Providencia rettgeri W986, as well as characterizing the enzymatic activity of FosA11 and the genetic environment. Antimicrobial susceptibility testing was performed using the agar microdilution method based on the Clinical and Laboratory Standards Institute guidelines. The whole genomic sequence of Providencia rettgeri W986 was obtained using Illumina sequencing and the PacBio platform. The fosA-11 gene was amplified by PCR and cloned into the pUCP20 vector. The recombinant strain pCold1-fosA11-BL21 was expressed to extract the target protein, and absorbance photometry was applied for enzymatic parameter determination. Minimal inhibitory concentration (MIC) tests showed that W986 conferred fosfomycin resistance and was inhibited by phosphonoformate, thereby indicating the presence of a FosA protein. A novel resistance gene designated as fosA11 was identified by whole-genome sequencing and bioinformatics analysis, and it shared 54.41%-64.23% amino acid identity with known FosA proteins. Cloning fosA11 into Escherichia coli obtained a significant increase (32-fold) in the MIC with fosfomycin. Determination of the enzyme kinetics showed that FosA11 had a high catalytic effect on fosfomycin, with Km = 18 ± 4 and Kcat = 56.1 ± 3.2. We also found that fosA11 was located on the chromosome, but the difference in the GC content between the chromosome and fosA11 was dubious, and thus further investigation is required. In this study, we identified and characterized a novel fosfomycin inactivation enzyme called FosA11. The origin and prevalence of the fosA11 gene in other bacteria require further investigation.IMPORTANCEFosfomycin is an effective antimicrobial agent against Enterobacterales strains. However, the resistance rate of fosfomycin is increasing year by year. Therefore, it is necessary to study the deep molecular mechanism of bacterial resistance to fosfomycin. We identified a novel chromosomal fosfomycin glutathione S-transferase, FosA11 from Providencia rettgeri, which shares a very low identity (54.41%-64.23%) with the previously known FosA and exhibits highly efficient catalytic ability against fosfomycin. Analysis of the genetic context and origin of fosA11 displays that the gene and its surrounding environments are widely conserved in Providencia and no mobile elements are discovered, implying that FosA11 may be broadly important in the natural resistance to fosfomycin of Providencia species.
Collapse
Affiliation(s)
- Wei Lu
- Department of Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
- The Fourth School of Medicine Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Shihan Zhou
- The Fourth School of Medicine Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Xueli Ma
- Department of Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
| | - Nuo Xu
- The Fourth School of Medicine Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Dongxin Liu
- Department of Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
| | - Keqing Zhang
- Department of Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
| | - Yongke Zheng
- The Fourth School of Medicine Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
- Department of Intensive Care Unit, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
| | - Shenghai Wu
- Department of Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, China
- The Fourth School of Medicine Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| |
Collapse
|
4
|
Lysitsas M, Chatzipanagiotidou I, Billinis C, Valiakos G. Fosfomycin Resistance in Bacteria Isolated from Companion Animals (Dogs and Cats). Vet Sci 2023; 10:vetsci10050337. [PMID: 37235420 DOI: 10.3390/vetsci10050337] [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: 03/31/2023] [Revised: 04/25/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Fosfomycin is an old antibacterial agent, which is currently used mainly in human medicine, in uncomplicated Urinary Tract Infections (UTIs). The purpose of this review is to investigate the presence and the characteristics of Fosfomycin resistance in bacteria isolated from canine or feline samples, estimate the possible causes of the dissemination of associated strains in pets, and underline the requirements of prospective relevant studies. Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines were used for the search of current literature in two databases. A total of 33 articles were finally included in the review. Relevant data were tracked down, assembled, and compared. Referring to the geographical distribution, Northeast Asia was the main area of origin of the studies. E. coli was the predominant species detected, followed by other Enterobacteriaceae, Staphylococci, and Pseudomonas spp. FosA and fosA3 were the more frequently encountered Antimicrobial Resistance Genes (ARGs) in the related Gram-negative isolates, while fosB was regularly encountered in Gram-positive ones. The majority of the strains were multidrug-resistant (MDR) and co-carried resistance genes against several classes of antibiotics and especially β-Lactams, such as blaCTX-M and mecA. These results demonstrate the fact that the cause of the spreading of Fosfomycin-resistant bacteria among pets could be the extended use of other antibacterial agents, that promote the prevalence of MDR, epidemic strains among an animal population. Through the circulation of these strains into a community, a public health issue could arise. Further research is essential though, for the comprehensive consideration of the issue, as the current data are limited.
Collapse
Affiliation(s)
- Marios Lysitsas
- Faculty of Veterinary Science, University of Thessaly, 43100 Karditsa, Greece
| | | | | | - George Valiakos
- Faculty of Veterinary Science, University of Thessaly, 43100 Karditsa, Greece
| |
Collapse
|
5
|
Tanwar AS, Shruptha P, Paul B, Murali TS, Brand A, Satyamoorthy K. How Can Omics Inform Diabetic Foot Ulcer Clinical Management? A Whole Genome Comparison of Four Clinical Strains of Staphylococcus aureus. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2023; 27:51-61. [PMID: 36753700 DOI: 10.1089/omi.2022.0184] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Foot ulcers and associated infections significantly contribute to morbidity and mortality in diabetes. While diverse pathogens are found in the diabetes-related infected ulcers, Staphylococcus aureus remains one of the most virulent and widely prevalent pathogens. The high prevalence of S. aureus in chronic wound infections, especially in clinical settings, is attributed to its ability to evolve and acquire resistance against common antibiotics and to elicit an array of virulence factors. In this study, whole genome comparison of four strains of S. aureus (MUF168, MUF256, MUM270, and MUM475) isolated from diabetic foot ulcer (DFU) infections showing varying resistance patterns was carried out to study the genomic similarity, antibiotic resistance profiling, associated virulence factors, and sequence variations in drug targets. The comparative genome analysis showed strains MUM475 and MUM270 to be highly resistant, MUF256 with moderate levels of resistance, and MUF168 to be the least resistant. Strain MUF256 and MUM475 harbored more virulence factors compared with other two strains. Deleterious sequence variants were observed suggesting potential role in altering drug targets and drug efficacy. This comparative whole genome study offers new molecular insights that may potentially inform evidence-based diagnosis and treatment of DFUs in the clinic.
Collapse
Affiliation(s)
- Ankit Singh Tanwar
- Department of Public Health Genomics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India.,United Nations University-Maastricht Economic and Social Research Institute on Innovation and Technology (UNU-MERIT), Maastricht, The Netherlands
| | - Padival Shruptha
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Bobby Paul
- Department of Bioinformatics, and Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Thokur Sreepathy Murali
- Department of Biotechnology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Angela Brand
- Department of Public Health Genomics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India.,United Nations University-Maastricht Economic and Social Research Institute on Innovation and Technology (UNU-MERIT), Maastricht, The Netherlands.,Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| |
Collapse
|
6
|
Travis S, Green KD, Gilbert NC, Tsodikov OV, Garneau-Tsodikova S, Thompson MK. Inhibition of Fosfomycin Resistance Protein FosB from Gram-Positive Pathogens by Phosphonoformate. Biochemistry 2023; 62:109-117. [PMID: 36525630 DOI: 10.1021/acs.biochem.2c00566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Gram-positive pathogen Staphylococcus aureus is a leading cause of antimicrobial resistance related deaths worldwide. Like many pathogens with multidrug-resistant strains, S. aureus contains enzymes that confer resistance through antibiotic modification(s). One such enzyme present in S. aureus is FosB, a Mn2+-dependent l-cysteine or bacillithiol (BSH) transferase that inactivates the antibiotic fosfomycin. fosB gene knockout experiments show that the minimum inhibitory concentration (MIC) of fosfomycin is significantly reduced when the FosB enzyme is not present. This suggests that inhibition of FosB could be an effective method to restore fosfomycin activity. We used high-throughput in silico-based screening to identify small-molecule analogues of fosfomycin that inhibited thiol transferase activity. Phosphonoformate (PPF) was a top hit from our approach. Herein, we have characterized PPF as a competitive inhibitor of FosB from S. aureus (FosBSa) and Bacillus cereus (FosBBc). In addition, we have determined a crystal structure of FosBBc with PPF bound in the active site. Our results will be useful for future structure-based development of FosB inhibitors that can be delivered in combination with fosfomycin in order to increase the efficacy of this antibiotic.
Collapse
Affiliation(s)
- Skye Travis
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, Alabama 35487, United States
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Nathaniel C Gilbert
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, Alabama 35487, United States
| |
Collapse
|
7
|
El-Khoury C, Mansour E, Yuliandra Y, Lai F, Hawkins BA, Du JJ, Sundberg EJ, Sluis-Cremer N, Hibbs DE, Groundwater PW. The role of adjuvants in overcoming antibacterial resistance due to enzymatic drug modification. RSC Med Chem 2022; 13:1276-1299. [PMID: 36439977 PMCID: PMC9667779 DOI: 10.1039/d2md00263a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/16/2022] [Indexed: 02/03/2023] Open
Abstract
Antibacterial resistance is a prominent issue with monotherapy often leading to treatment failure in serious infections. Many mechanisms can lead to antibacterial resistance including deactivation of antibacterial agents by bacterial enzymes. Enzymatic drug modification confers resistance to β-lactams, aminoglycosides, chloramphenicol, macrolides, isoniazid, rifamycins, fosfomycin and lincosamides. Novel enzyme inhibitor adjuvants have been developed in an attempt to overcome resistance to these agents, only a few of which have so far reached the market. This review discusses the different enzymatic processes that lead to deactivation of antibacterial agents and provides an update on the current and potential enzyme inhibitors that may restore bacterial susceptibility.
Collapse
Affiliation(s)
- Christy El-Khoury
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Elissar Mansour
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Yori Yuliandra
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Felcia Lai
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Bryson A Hawkins
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Jonathan J Du
- Department of Biochemistry, Emory University School of Medicine Atlanta GA 30322 USA
| | - Eric J Sundberg
- Department of Biochemistry, Emory University School of Medicine Atlanta GA 30322 USA
| | - Nicolas Sluis-Cremer
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine Pittsburgh PA 15213 USA
| | - David E Hibbs
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| | - Paul W Groundwater
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Sydney NSW 2006 Australia
| |
Collapse
|
8
|
Crystal structure and biochemical analysis suggest that YjoB ATPase is a putative substrate-specific molecular chaperone. Proc Natl Acad Sci U S A 2022; 119:e2207856119. [PMID: 36191235 PMCID: PMC9565160 DOI: 10.1073/pnas.2207856119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AAA+ ATPases are ubiquitous proteins associated with most cellular processes, including DNA unwinding and protein unfolding. Their functional and structural properties are typically determined by domains and motifs added to the conserved ATPases domain. Currently, the molecular function and structure of many ATPases remain elusive. Here, we report the crystal structure and biochemical analyses of YjoB, a Bacillus subtilis AAA+ protein. The crystal structure revealed that the YjoB hexamer forms a bucket hat-shaped structure with a porous chamber. Biochemical analyses showed that YjoB prevents the aggregation of vegetative catalase KatA and gluconeogenesis-specific glyceraldehyde-3 phosphate dehydrogenase GapB but not citrate synthase, a conventional substrate. Structural and biochemical analyses further showed that the internal chamber of YjoB is necessary for inhibition of substrate aggregation. Our results suggest that YjoB, conserved in the class Bacilli, is a potential molecular chaperone acting in the starvation/stationary phases of B. subtilis growth.
Collapse
|
9
|
Wangchinda W, Rattanaumpawan P. JMM Profile: Fosfomycin: a potential antibiotic for multi- and extensively resistant bacteria. J Med Microbiol 2022; 71. [PMID: 35951643 DOI: 10.1099/jmm.0.001573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fosfomycin (FOF) is the first antimicrobial of the epoxide class. It is commercially available in oral and parenteral formulations. Oral FOF is widely used to treat uncomplicated cystitis in women, while parenteral FOF is extensively utilized for upper urinary tract infections. FOF has a broad-spectrum bactericidal activity with a low risk of cross-resistance to other antimicrobial classes. Therefore, parenteral FOF is increasingly prescribed adjunctive therapy to treat extra-urinary tract infections caused by multidrug-resistant, Gram-negative bacteria.
Collapse
Affiliation(s)
- Walaiporn Wangchinda
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wang Lang Rd, Bangkoknoi, Bangkok 10700, Thailand
| | - Pinyo Rattanaumpawan
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wang Lang Rd, Bangkoknoi, Bangkok 10700, Thailand
| |
Collapse
|
10
|
Wiltsie V, Travis S, Shay MR, Simmons Z, Frantom P, Thompson MK. Structural and functional characterization of fosfomycin resistance conferred by FosB from Enterococcus faecium. Protein Sci 2022; 31:580-590. [PMID: 34882867 PMCID: PMC8862413 DOI: 10.1002/pro.4253] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 11/10/2022]
Abstract
The Gram-positive pathogen Enterococcus faecium is one of the leading causes of hospital-acquired vancomycin resistant enterococci (VRE) infections. E. faecium has extensive multidrug resistance and accounts for more than two million infections in the United States each year. FosB is a fosfomycin resistance enzyme found in Gram-positive pathogens like E. faecium. Typically, the FosB enzymes are Mn2+ -dependent bacillithiol (BSH) transferases that inactivate fosfomycin through nucleophilic addition of the thiol to the antibiotic. However, our kinetic analysis of FosBEf shows that the enzyme does not utilize BSH as a thiol substrate, unlike the other well characterized FosB enzymes. Here we report that FosBEf is a Mn2+ -dependent L-cys transferase. In addition, we have determined the three-dimensional X-ray crystal structure of FosBEf in complex with fosfomycin at a resolution of 2.0 Å. A sequence similarity network (SSN) was generated for the FosB family to investigate the unexpected substrate selectivity. Three non-conserved residues were identified in the SSN that may contribute to the substrate selectivity differences in the family of enzymes. Our structural and functional characterization of FosBEf establishes the enzyme as a potential target and may prove useful for future structure-based development of FosB inhibitors to increase the efficacy of fosfomycin.
Collapse
Affiliation(s)
- Vanessa Wiltsie
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Skye Travis
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Madeline R. Shay
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Zachary Simmons
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Patrick Frantom
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Matthew K. Thompson
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| |
Collapse
|
11
|
Differences in fosfomycin resistance mechanisms between Pseudomonas aeruginosa and Enterobacterales. Antimicrob Agents Chemother 2021; 66:e0144621. [PMID: 34807759 DOI: 10.1128/aac.01446-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant (MDR) Pseudomonas aeruginosa presents a serious threat to public health due to its widespread resistance to numerous antibiotics. P. aeruginosa commonly causes nosocomial infections including urinary tract infections (UTI) which have become increasingly difficult to treat. The lack of effective therapeutic agents has renewed interest in fosfomycin, an old drug discovered in the 1960s and approved prior to the rigorous standards now required for drug approval. Fosfomycin has a unique structure and mechanism of action, making it a favorable therapeutic alternative for MDR pathogens that are resistant to other classes of antibiotics. The absence of susceptibility breakpoints for fosfomycin against P. aeruginosa limits its clinical use and interpretation due to extrapolation of breakpoints established for Escherichia coli or Enterobacterales without supporting evidence. Furthermore, fosfomycin use and efficacy for treatment of P. aeruginosa is also limited by both inherent and acquired resistance mechanisms. This narrative review provides an update on currently identified resistance mechanisms to fosfomycin, with a focus on those mediated by P. aeruginosa such as peptidoglycan recycling enzymes, chromosomal Fos enzymes, and transporter mutation. Additional fosfomycin resistance mechanisms exhibited by Enterobacterales including mutations in transporters and associated regulators, plasmid mediated Fos enzymes, kinases, and murA modification, are also summarized and contrasted. These data highlight that different fosfomycin resistance mechanisms may be associated with elevated MIC values in P. aeruginosa compared to Enterobacterales, emphasizing that extrapolation of E. coli breakpoints to P. aeruginosa should be avoided.
Collapse
|
12
|
Phenotypic and Genomic Profiling of Staphylococcus argenteus in Canada and the United States and Recommendations for Clinical Result Reporting. J Clin Microbiol 2021; 59:JCM.02470-20. [PMID: 33731414 DOI: 10.1128/jcm.02470-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/07/2021] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus argenteus is a newly described species, formerly known as S. aureus clonal complex 75 (CC75). Here, we describe the largest collection of S. argenteus isolates in North America, highlighting identification challenges. We present phenotypic and genomic characteristics and provide recommendations for clinical reporting. Between 2017 and 2019, 22 isolates of S. argenteus were received at 2 large reference laboratories for identification. Identification with routine methods (biochemical, matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS], 16S rRNA gene analysis) proved challenging to confidently distinguish these isolates from S. aureus Whole-genome sequencing analysis was employed to confirm identifications. Using several different sequence-based analyses, all clinical isolates under investigation were confirmed to be S. argenteus with clear differentiation from S. aureus Seven of 22 isolates were recovered from sterile sites, 11 from nonsterile sites, and 4 from surveillance screens. While sequence types ST1223/coa type XV, ST2198/coa type XIV, and ST2793/coa type XId were identified among the Canadian isolates, the majority of isolates (73%) belonged to multilocus sequence types (MLST) ST2250/coa type XId and exhibited a high degree of homology at the genomic level. Despite this similarity, 5 spa types were identified among ST2250 isolates, demonstrating some diversity between strains. Several isolates carried mecA, as well as other resistance and virulence determinants (e.g., PVL, TSST-1) commonly associated with S. aureus Based on our findings, the growing body of literature on S. argenteus, the potential severity of infections, and possible confusion associated with reporting, including use of incorrect breakpoints for susceptibility results, we make recommendations for clinical laboratories regarding this organism.
Collapse
|
13
|
Lima AH, Silva JR, Alves C, Lameira J. QM/MM Study of the Fosfomycin Resistance Mechanism Involving FosB Enzyme. ACS OMEGA 2021; 6:12507-12512. [PMID: 34056400 PMCID: PMC8154160 DOI: 10.1021/acsomega.1c00096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/12/2021] [Indexed: 06/01/2023]
Abstract
Multidrug-resistant organisms contain antibiotic-modifying enzymes that facilitate resistance to a variety of antimicrobial compounds. Particularly, the fosfomycin (FOF) drug can be structurally modified by several FOF-modifying enzymes before it reaches the biological target. Among them, FosB is an enzyme that utilizes l-cysteine or bacillithiol in the presence of a divalent metal to open the epoxide ring of FOF and, consequently, inactivate the drug. Here, we have used hybrid quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) simulations to explore the mechanism of the reaction involving FosB and FOF. The calculated free-energy profiles show that the cost to open the epoxide ring of FOF at the C2 atom is ∼3.0 kcal/mol higher than that at the C1 atom. Besides, our QM/MM MD results revealed the critical role of conformation change of Cys9 and Asn50 to release the drug from the active site. Overall, the present study provides insights into the mechanism of FOF-resistant proteins.
Collapse
Affiliation(s)
- Anderson H. Lima
- Laboratório de Planejamento
e Desenvolvimento de Fármacos, Instituto de Ciências
Exatas e Naturais, Universidade Federal
do Pará, Rua Augusto Corrêa, 01, 66075-110, Belém, Pará, Brasil
| | - José Rogério
A. Silva
- Laboratório de Planejamento
e Desenvolvimento de Fármacos, Instituto de Ciências
Exatas e Naturais, Universidade Federal
do Pará, Rua Augusto Corrêa, 01, 66075-110, Belém, Pará, Brasil
| | - Cláudio
Nahum Alves
- Laboratório de Planejamento
e Desenvolvimento de Fármacos, Instituto de Ciências
Exatas e Naturais, Universidade Federal
do Pará, Rua Augusto Corrêa, 01, 66075-110, Belém, Pará, Brasil
| | - Jerônimo Lameira
- Laboratório de Planejamento
e Desenvolvimento de Fármacos, Instituto de Ciências
Exatas e Naturais, Universidade Federal
do Pará, Rua Augusto Corrêa, 01, 66075-110, Belém, Pará, Brasil
| |
Collapse
|
14
|
Hou Q, Kolodkin-Gal I. Harvesting the complex pathways of antibiotic production and resistance of soil bacilli for optimizing plant microbiome. FEMS Microbiol Ecol 2021; 96:5872479. [PMID: 32672816 DOI: 10.1093/femsec/fiaa142] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/13/2020] [Indexed: 01/04/2023] Open
Abstract
A sustainable future increasing depends on our capacity to utilize beneficial plant microbiomes to meet our growing needs. Plant microbiome symbiosis is a hallmark of the beneficial interactions between bacteria and their host. Specifically, colonization of plant roots by biocontrol agents and plant growth-promoting bacteria can play an important role in maintaining the optimal rhizosphere environment, supporting plant growth and promoting its fitness. Rhizosphere communities confer immunity against a wide range of foliar diseases by secreting antibiotics and activating plant defences. At the same time, the rhizosphere is a highly competitive niche, with multiple microbial species competing for space and resources, engaged in an arms race involving the production of a vast array of antibiotics and utilization of a variety of antibiotic resistance mechanisms. Therefore, elucidating the mechanisms that govern antibiotic production and resistance in the rhizosphere is of great significance for designing beneficial communities with enhanced biocontrol properties. In this review, we used Bacillus subtilis and B. amyloliquefaciens as models to investigate the genetics of antibiosis and the potential for its translation of into improved plant microbiome performance.
Collapse
Affiliation(s)
- Qihui Hou
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
15
|
Chen L, Ou B, Zhang M, Chou CH, Chang SK, Zhu G. Coexistence of Fosfomycin Resistance Determinant fosA and fosA3 in Enterobacter cloacae Isolated from Pets with Urinary Tract Infection in Taiwan. Microb Drug Resist 2020; 27:415-423. [PMID: 32667841 DOI: 10.1089/mdr.2020.0077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To analyze the characteristics of fosA and fosA3 in Enterobacter cloacae isolated from aspirated and catheterized urine culture specimens of companion pets in Taiwan. A total of 19 E. cloacae isolates from pets with urinary tract infection were screened for the presence of fosA, fosA3, and fosC2 and for the genetic context of them by PCR amplification and sequencing. The transferability, resistance phenotypes, plasmid replicon typing properties and genetic environments of fosA- and/or fosA3-positive strains were characterized. Five E. cloacae isolates were positive for fosA and three coharbored fosA and fosA3. No fosC determinant was detected. Transconjugants of fosA3 were successfully acquired, while the acquisition of fosA transconjugants was failed. The minimum inhibitory concentrations (MICs) of the three fosA3-positive isolates and their transconjugants were ≥256 mg/L, whereas the MICs of the five fosA-positive isolates ranged from 64 mg/L to 256 mg/L. Three plasmid replicons (InCFrepB, InCL/M, and InCHI2) were identified in fosA- and fosA3-positive E. cloacae isolates. Different genetic contexts lay in the downstream region of fosA and fosA3, respectively. Eight distinct patterns based on the similarity value of more than 80% were typed for all the 8 fosA-positive isolates. In conclusion, the fosA concomitant with fosA3 were found in E. cloacae isolates. The fosA3 not only exhibits stronger activity of inactivating fosfomycin than fosA but also possesses stronger potential to spread than fosA. Different genetic backgrounds exist in these fosA- and fosA3-positive isolates, and different mobile elements may confer the dissemination of fosA and fosA3.
Collapse
Affiliation(s)
- Lin Chen
- School of Veterinary Medicine, Jiangsu Agri-animal Husbandry Vocational College, Taizhou, China
| | - Bingming Ou
- College of Life Science, Zhaoqing University, Zhaoqing, China.,College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Minyu Zhang
- College of Life Science, Zhaoqing University, Zhaoqing, China
| | - Chung-Hsi Chou
- School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Shao-Kuang Chang
- School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| |
Collapse
|
16
|
Ouyang Y, Li J, Peng Y, Huang Z, Ren Q, Lu J. The Role and Mechanism of Thiol-Dependent Antioxidant System in Bacterial Drug Susceptibility and Resistance. Curr Med Chem 2020; 27:1940-1954. [DOI: 10.2174/0929867326666190524125232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 01/24/2019] [Accepted: 02/21/2019] [Indexed: 12/16/2022]
Abstract
Antibiotics play an irreplaceable role in the prevention and treatment of bacterial infection
diseases. However, because of the improper use of antibiotics, bacterial resistance emerges as a major
challenge of public health all over the world. The small thiol molecules such as glutathione can directly
react and conjugate with some antibiotics, which thus contribute to drug susceptibility and resistance.
Recently, accumulating evidence shows that there is a close link between the antibacterial activities of
some antibiotics and Reactive Oxygen Species (ROS). Thioredoxin and glutathione systems are two
main cellular disulfide reductase systems maintaining cellular ROS level. Therefore, these two thioldependent
antioxidant systems may affect the antibiotic susceptibility and resistance. Microorganisms
are equipped with different thiol-dependent antioxidant systems, which make the role of thioldependent
antioxidant systems in antibiotic susceptibility and resistance is different in various bacteria.
Here we will focus on the review on the advances of the effects of thiol-dependent antioxidant system
in the bacterial antibiotic susceptibility and resistance.
Collapse
Affiliation(s)
- Yanfang Ouyang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Jing Li
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Yi Peng
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Zhijun Huang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Qiao Ren
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Jun Lu
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education (Southwest University), College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| |
Collapse
|
17
|
Travis S, Shay MR, Manabe S, Gilbert NC, Frantom PA, Thompson MK. Characterization of the genomically encoded fosfomycin resistance enzyme from Mycobacterium abscessus. MEDCHEMCOMM 2019; 10:1948-1957. [PMID: 32952996 PMCID: PMC7478155 DOI: 10.1039/c9md00372j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/17/2019] [Indexed: 01/03/2023]
Abstract
Mycobacterium abscessus belongs to a group of rapidly growing mycobacteria (RGM) and accounts for approximately 65-80% of lung disease caused by RGM. It is highly pathogenic and is considered the prominent Mycobacterium involved in pulmonary infection in patients with cystic fibrosis and chronic pulmonary disease (CPD). FosM is a putative 134 amino acid fosfomycin resistance enzyme from M. abscessus subsp. bolletii that shares approximately 30-55% sequence identity with other vicinal oxygen chelate (VOC) fosfomycin resistance enzymes and represents the first of its type found in any Mycobacterium species. Genes encoding VOC fosfomycin resistance enzymes have been found in both Gram-positive and Gram-negative pathogens. Given that FosA enzymes from Gram-negative bacteria have evolved optimum activity towards glutathione (GSH) and FosB enzymes from Gram-positive bacteria have evolved optimum activity towards bacillithiol (BSH), it was originally suggested that FosM might represent a fourth class of enzyme that has evolved to utilize mycothiol (MSH). However, a sequence similarity network (SSN) analysis identifies FosM as a member of the FosX subfamily, indicating that it may utilize water as a substrate. Here we have synthesized MSH and characterized FosM with respect to divalent metal ion activation and nucleophile selectivity. Our results indicate that FosM is a Mn2+-dependent FosX-type hydrase with no selectivity toward MSH or other thiols as analyzed by NMR and mass spectroscopy.
Collapse
Affiliation(s)
- Skye Travis
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Madeline R Shay
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Shino Manabe
- Synthetic Cellular Chemistry Laboratory , RIKEN , Hirosawa , Wako , Saitama 351-0198 , Japan
| | - Nathaniel C Gilbert
- Center for Advanced Microstructures and Devices , Louisiana State University , 6980 Jefferson Highway , Baton Rouge , Louisiana 70806 , USA
| | - Patrick A Frantom
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| |
Collapse
|
18
|
Kobayashi K, Ikemoto Y. Biofilm-associated toxin and extracellular protease cooperatively suppress competitors in Bacillus subtilis biofilms. PLoS Genet 2019; 15:e1008232. [PMID: 31622331 PMCID: PMC6818787 DOI: 10.1371/journal.pgen.1008232] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/29/2019] [Accepted: 10/04/2019] [Indexed: 12/17/2022] Open
Abstract
In nature, most bacteria live in biofilms where they compete with their siblings and other species for space and nutrients. Some bacteria produce antibiotics in biofilms; however, since the diffusion of antibiotics is generally hindered in biofilms by extracellular polymeric substances, i.e., the biofilm matrix, their function remains unclear. The Bacillus subtilis yitPOM operon is a paralog of the sdpABC operon, which produces the secreted peptide toxin SDP. Unlike sdpABC, yitPOM is induced in biofilms by the DegS-DegU two-component regulatory system. High yitPOM expression leads to the production of a secreted toxin called YIT. Expression of yitQ, which lies upstream of yitPOM, confers resistance to the YIT toxin, suggesting that YitQ is an anti-toxin protein for the YIT toxin. The alternative sigma factor SigW also contributes to YIT toxin resistance. In a mutant lacking yitQ and sigW, the YIT toxin specifically inhibits biofilm formation, and the extracellular neutral protease NprB is required for this inhibition. The requirement for NprB is eliminated by Δeps and ΔbslA mutations, either of which impairs production of biofilm matrix polymers. Overexpression of biofilm matrix polymers prevents the action of the SDP toxin but not the YIT toxin. These results indicate that, unlike the SDP toxin and many conventional antibiotics, the YIT toxin can pass through layers of biofilm matrix polymers to attack cells within biofilms with assistance from NprB. When the wild-type strain and the YIT-sensitive mutant were grown together on a solid medium, the wild-type strain formed biofilms that excluded the YIT-sensitive mutant. This observation suggests that the YIT toxin protects B. subtilis biofilms against competitors. Several bacteria are known to produce antibiotics in biofilms. We propose that some bacteria including B. subtilis may have evolved specialized antibiotics that can function within biofilms. Biofilms are multicellular aggregates of bacteria that are formed on various living and non-living surfaces. Biofilms often cause serious problems, including food contamination and infectious diseases. Since bacteria in biofilms exhibit increased tolerance or resistance to antimicrobials, new agents and treatments for combating biofilm-related problems are required. In this study, we demonstrated that B. subtilis produces a secreted peptide antibiotic called the YIT toxin and its resistant proteins in biofilms. A mutant lacking the resistance genes was defective in biofilm formation. This effect resulted from the ability of the YIT toxin to pass through the biofilm defense barrier and to attack biofilm cells. Thus, unlike many conventional antibiotics, the YIT toxin can penetrate biofilms and suppress the growth of YIT toxin-sensitive cells within biofilms. Some bacteria produce antibiotics in biofilms, some of which can alter the bacterial composition in the biofilms. Taking these observations into consideration, our findings suggest that some bacteria produce special antibiotics that are effective against bacteria in biofilms, and these antibiotics might serve as anti-biofilm agents.
Collapse
Affiliation(s)
- Kazuo Kobayashi
- Division of Biological Science, Nara Institute of Science & Technology, Ikoma, Nara, Japan
- * E-mail:
| | - Yukako Ikemoto
- Division of Biological Science, Nara Institute of Science & Technology, Ikoma, Nara, Japan
| |
Collapse
|
19
|
Zhao H, Roistacher DM, Helmann JD. Deciphering the essentiality and function of the anti-σ M factors in Bacillus subtilis. Mol Microbiol 2019; 112:482-497. [PMID: 30715747 PMCID: PMC6679829 DOI: 10.1111/mmi.14216] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2019] [Indexed: 12/27/2022]
Abstract
Bacteria use alternative sigma factors to adapt to different growth and stress conditions. The Bacillus subtilis extracytoplasmic function sigma factor SigM regulates genes for cell wall synthesis and is crucial for maintaining cell wall homeostasis under stress conditions. The activity of SigM is regulated by its anti-sigma factor, YhdL, and the accessory protein YhdK. Here, we show that dysregulation of SigM caused by the absence of either component of the anti-sigma factor complex leads to toxic levels of SigM and severe growth defects. High SigM activity results from a dysregulated positive feedback loop, and can be suppressed by overexpression of the housekeeping sigma, SigA. Using a sigM merodiploid strain, we selected for suppressor mutations that allow survival of yhdL depletion strain. The recovered suppressor mutations map to the beta and beta-prime subunits of RNA polymerase core enzyme and selectively reduce SigM activity, and in some cases increase the activity of other alternative sigma factors. This work highlights the ability of mutations in RNA polymerase that remodel the sigma-core interface to differentially affect sigma factor activity, and thereby alter the transcriptional landscape of the cell.
Collapse
Affiliation(s)
- Heng Zhao
- Cornell University, Department of Microbiology, Ithaca, NY, USA
| | | | - John D. Helmann
- Cornell University, Department of Microbiology, Ithaca, NY, USA
| |
Collapse
|
20
|
Helmann JD. Where to begin? Sigma factors and the selectivity of transcription initiation in bacteria. Mol Microbiol 2019; 112:335-347. [PMID: 31119812 DOI: 10.1111/mmi.14309] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transcription is the fundamental process that enables the expression of genetic information. DNA-directed RNA polymerase (RNAP) uses one strand of the DNA duplex as template to produce complementary RNA molecules that serve in translation (rRNA, tRNA), protein synthesis (mRNA) and regulation (sRNA). Although the RNAP core is catalytically competent for RNA synthesis, the selectivity of transcription initiation requires a sigma (σ) factor for promoter recognition and opening. Expression of alternative σ factors provides a powerful mechanism to control the expression of discrete sets of genes (a σ regulon) in response to specific nutritional, developmental or stress-related signals. Here, I review the key insights that led to the original discovery of σ factor 50 years ago and the subsequent discovery of alternative σ factors as a ubiquitous mechanism of bacterial gene regulation. These studies form a prelude to the more recent, genomics-enabled insights into the vast diversity of σ factors in bacteria.
Collapse
Affiliation(s)
- John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA
| |
Collapse
|
21
|
Song Z, Wang X, Zhou X, Jiang S, Li Y, Ahmad O, Qi L, Li P, Li J. Taxonomic Distribution of FosB in Human-Microbiota and Activity Comparison of Fosfomycin Resistance. Front Microbiol 2019; 10:200. [PMID: 30814984 PMCID: PMC6381061 DOI: 10.3389/fmicb.2019.00200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/24/2019] [Indexed: 12/30/2022] Open
Abstract
FosB, a Mg2+ dependent thioltransferase, confers antibiotic resistance to fosfomycin through enzymatic drug inactivation. Among all antibiotic resistant proteins in the Antibiotic Resistance Genes Database and the Comprehensive Antibiotic Resistance Database, FosB is within 5% of the most number of ARPs identified in Human Microbiome Project reference database but mainly distributed in limited genera, i.e., 122 of total 133 FosB homologues are found from Bacillus and Staphylococcus. Furthermore, these FosB sequences could be divided into three clusters based on their phylogenetic relationship, i.e., two groups of FosB were mainly from Bacillus, and another was mainly from Staphylococcus. Finally, we confirmed that FosB from the group of Staphylococcus presented the highest resistance ability to fosfomycin by in silico and in vitro comparisons. In summary, this study elaborates the specific taxonomic characteristics and resistant abilities of FosB in human microbiota, which might help in developing more promising fosfomycin-like antibiotics.
Collapse
Affiliation(s)
- Ziwei Song
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xue Wang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.,Key Laboratory of Drug Quality Control and Pharmacovigilance, China Pharmaceutical University, Nanjing, China
| | - Xingchen Zhou
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.,Key Laboratory of Drug Quality Control and Pharmacovigilance, China Pharmaceutical University, Nanjing, China
| | - Su Jiang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Yuanyuan Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Owais Ahmad
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Lianwen Qi
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China.,Clinical Metabolomics Center, China Pharmaceutical University, Nanjing, China
| | - Ping Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.,Key Laboratory of Drug Quality Control and Pharmacovigilance, China Pharmaceutical University, Nanjing, China
| |
Collapse
|
22
|
Falagas ME, Athanasaki F, Voulgaris GL, Triarides NA, Vardakas KZ. Resistance to fosfomycin: Mechanisms, Frequency and Clinical Consequences. Int J Antimicrob Agents 2018; 53:22-28. [PMID: 30268576 DOI: 10.1016/j.ijantimicag.2018.09.013] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 09/11/2018] [Accepted: 09/16/2018] [Indexed: 12/17/2022]
Abstract
Fosfomycin has been used for the treatment of infections due to susceptible and multidrug-resistant (MDR) bacteria. It inhibits bacterial cell wall synthesis through a unique mechanism of action at a step prior to that inhibited by β-lactams. Fosfomycin enters the bacterium through membrane channels/transporters and inhibits MurA, which initiates peptidoglycan (PG) biosynthesis of the bacterial cell wall. Several bacteria display inherent resistance to fosfomycin mainly through MurA mutations. Acquired resistance involves, in order of decreasing frequency, modifications of membrane transporters that prevent fosfomycin from entering the bacterial cell, acquisition of plasmid-encoded genes that inactivate fosfomycin, and MurA mutations. Fosfomycin resistance develops readily in vitro but less so in vivo. Mutation frequency is higher among Pseudomonas aeruginosa and Klebsiella spp. compared with Escherichia coli and is associated with fosfomycin concentration. Mutations in cAMP regulators, fosfomycin transporters and MurA seem to be associated with higher biological cost in Enterobacteriaceae but not in Pseudomonas spp. The contribution of fosfomycin inactivating enzymes in emergence and spread of fosfomycin resistance currently seems low-to-moderate, but their presence in transferable plasmids may potentially provide the best means for the spread of fosfomycin resistance in the future. Their co-existence with genes conferring resistance to other antibiotic classes may increase the emergence of MDR strains. Although susceptibility rates vary, rates seem to increase in settings with higher fosfomycin use and among multidrug-resistant pathogens.
Collapse
Affiliation(s)
- Matthew E Falagas
- Alfa Institute of Biomedical Sciences (AIBS), Athens, Greece; Department of Medicine, Henry Dunant Hospital Center, Athens, Greece; Tufts University School of Medicine, Boston, Massachusetts, USA.
| | | | - Georgios L Voulgaris
- Laboratory of Pharmacokinetics and Toxicology, Department of Pharmacy, 401 General Military Hospital, Athens, Greece
| | - Nikolaos A Triarides
- Alfa Institute of Biomedical Sciences (AIBS), Athens, Greece; Department of Medicine, Henry Dunant Hospital Center, Athens, Greece
| | - Konstantinos Z Vardakas
- Alfa Institute of Biomedical Sciences (AIBS), Athens, Greece; Department of Medicine, Henry Dunant Hospital Center, Athens, Greece
| |
Collapse
|
23
|
Patel V, Wu Q, Chandrangsu P, Helmann JD. A metabolic checkpoint protein GlmR is important for diverting carbon into peptidoglycan biosynthesis in Bacillus subtilis. PLoS Genet 2018; 14:e1007689. [PMID: 30248093 PMCID: PMC6171935 DOI: 10.1371/journal.pgen.1007689] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 10/04/2018] [Accepted: 09/11/2018] [Indexed: 12/18/2022] Open
Abstract
The Bacillus subtilis GlmR (formerly YvcK) protein is essential for growth on gluconeogenic carbon sources. Mutants lacking GlmR display a variety of phenotypes suggestive of impaired cell wall synthesis including antibiotic sensitivity, aberrant cell morphology and lysis. To define the role of GlmR, we selected suppressor mutations that ameliorate the sensitivity of a glmR null mutant to the beta-lactam antibiotic cefuroxime or restore growth on gluconeogenic carbon sources. Several of the resulting suppressors increase the expression of the GlmS and GlmM proteins that catalyze the first two committed steps in the diversion of carbon from central carbon metabolism into peptidoglycan biosynthesis. Chemical complementation studies indicate that the absence of GlmR can be overcome by provision of cells with N-acetylglucosamine (GlcNAc), even under conditions where GlcNAc cannot re-enter central metabolism and serve as a carbon source for growth. Our results indicate that GlmR facilitates the diversion of carbon from the central metabolite fructose-6-phosphate, which is limiting in cells growing on gluconeogenic carbon sources, into peptidoglycan biosynthesis. Our data suggest that GlmR stimulates GlmS activity, and we propose that this activation is antagonized by the known GlmR ligand and peptidoglycan intermediate UDP-GlcNAc. Thus, GlmR presides over a new mechanism for the regulation of carbon partitioning between central metabolism and peptidoglycan biosynthesis.
Collapse
Affiliation(s)
- Vaidehi Patel
- Cornell University, Department of Microbiology, Ithaca, NY, United States of America
| | - Qun Wu
- Cornell University, Department of Microbiology, Ithaca, NY, United States of America
- School of Biotechnology, Jiangnan University, Wuxi, China
| | - Pete Chandrangsu
- Cornell University, Department of Microbiology, Ithaca, NY, United States of America
| | - John D. Helmann
- Cornell University, Department of Microbiology, Ithaca, NY, United States of America
- * E-mail:
| |
Collapse
|
24
|
Synthetic antimicrobial peptides delocalize membrane bound proteins thereby inducing a cell envelope stress response. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2416-2427. [PMID: 29894683 DOI: 10.1016/j.bbamem.2018.06.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 05/24/2018] [Accepted: 06/06/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Three amphipathic cationic antimicrobial peptides (AMPs) were characterized by determining their effect on Gram-positive bacteria using Bacillus subtilis strain 168 as a model organism. These peptides were TC19 and TC84, derivatives of thrombocidin-1 (TC-1), the major AMPs of human blood platelets, and Bactericidal Peptide 2 (BP2), a synthetic designer peptide based on human bactericidal permeability increasing protein (BPI). METHODS To elucidate the possible mode of action of the AMPs we performed a transcriptomic analysis using microarrays. Physiological analyses were performed using transmission electron microscopy (TEM), fluorescence microscopy and various B. subtilis mutants that produce essential membrane bound proteins fused to green fluorescent protein (GFP). RESULTS The transcriptome analysis showed that the AMPs induced a cell envelope stress response (cell membrane and cell wall). The cell membrane stress response was confirmed with the physiological observations that TC19, TC84 and BP2 perturb the membrane of B. subtilis. Using B. subtilis mutants, we established that the cell wall stress response is due to the delocalization of essential membrane bound proteins involved in cell wall synthesis. Other essential membrane proteins, involved in cell membrane synthesis and metabolism, were also delocalized due to alterations caused by the AMPs. CONCLUSIONS We showed that peptides TC19, TC84 and BP2 perturb the membrane causing essential proteins to delocalize, thus preventing the possible repair of the cell envelope after the initial interference with the membrane. GENERAL SIGNIFICANCE These AMPs show potential for eventual clinical application against Gram-positive bacterial cells and merit further application-oriented investigation.
Collapse
|
25
|
Santiago M, Lee W, Fayad AA, Coe KA, Rajagopal M, Do T, Hennessen F, Srisuknimit V, Müller R, Meredith TC, Walker S. Genome-wide mutant profiling predicts the mechanism of a Lipid II binding antibiotic. Nat Chem Biol 2018; 14:601-608. [PMID: 29662210 PMCID: PMC5964011 DOI: 10.1038/s41589-018-0041-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 02/27/2018] [Indexed: 12/11/2022]
Abstract
Identifying targets of antibacterial compounds remains a challenging step in antibiotic development. We have developed a two-pronged functional genomics approach to predict mechanism of action that uses mutant fitness data from antibiotic-treated transposon libraries containing both upregulation and inactivation mutants. We treated a Staphylococcus aureus transposon library containing 690,000 unique insertions with 32 antibiotics. Upregulation signatures, identified from directional biases in insertions, revealed known molecular targets and resistance mechanisms for the majority of these. Because single gene upregulation does not always confer resistance, we used a complementary machine learning approach to predict mechanism from inactivation mutant fitness profiles. This approach suggested the cell wall precursor Lipid II as the molecular target of the lysocins, a mechanism we have confirmed. We conclude that docking to membrane-anchored Lipid II precedes the selective bacteriolysis that distinguishes these lytic natural products, showing the utility of our approach for nominating antibiotic mechanism of action.
Collapse
Affiliation(s)
- Marina Santiago
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Wonsik Lee
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Antoine Abou Fayad
- Department of Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Kathryn A Coe
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Mithila Rajagopal
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Truc Do
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Fabienne Hennessen
- Department of Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Veerasak Srisuknimit
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Rolf Müller
- Department of Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Saarbrücken, Germany.
| | - Timothy C Meredith
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA. .,Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA.
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA. .,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
| |
Collapse
|
26
|
Abstract
SIGNIFICANCE Since the discovery and structural characterization of bacillithiol (BSH), the biochemical functions of BSH-biosynthesis enzymes (BshA/B/C) and BSH-dependent detoxification enzymes (FosB, Bst, GlxA/B) have been explored in Bacillus and Staphylococcus species. It was shown that BSH plays an important role in detoxification of reactive oxygen and electrophilic species, alkylating agents, toxins, and antibiotics. Recent Advances: More recently, new functions of BSH were discovered in metal homeostasis (Zn buffering, Fe-sulfur cluster, and copper homeostasis) and virulence control in Staphylococcus aureus. Unexpectedly, strains of the S. aureus NCTC8325 lineage were identified as natural BSH-deficient mutants. Modern mass spectrometry-based approaches have revealed the global reach of protein S-bacillithiolation in Firmicutes as an important regulatory redox modification under hypochlorite stress. S-bacillithiolation of OhrR, MetE, and glyceraldehyde-3-phosphate dehydrogenase (Gap) functions, analogous to S-glutathionylation, as both a redox-regulatory device and in thiol protection under oxidative stress. CRITICAL ISSUES Although the functions of the bacilliredoxin (Brx) pathways in the reversal of S-bacillithiolations have been recently addressed, significantly more work is needed to establish the complete Brx reduction pathway, including the major enzyme(s), for reduction of oxidized BSH (BSSB) and the targets of Brx action in vivo. FUTURE DIRECTIONS Despite the large number of identified S-bacillithiolated proteins, the physiological relevance of this redox modification was shown for only selected targets and should be a subject of future studies. In addition, many more BSH-dependent detoxification enzymes are evident from previous studies, although their roles and biochemical mechanisms require further study. This review of BSH research also pin-points these missing gaps for future research. Antioxid. Redox Signal. 28, 445-462.
Collapse
Affiliation(s)
- Pete Chandrangsu
- 1 Department of Microbiology, Cornell University , Ithaca, New York
| | - Vu Van Loi
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - Haike Antelmann
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - John D Helmann
- 1 Department of Microbiology, Cornell University , Ithaca, New York
| |
Collapse
|
27
|
Schultz D, Schlüter R, Gerth U, Lalk M. Metabolic Perturbations in a Bacillus subtilis clpP Mutant during Glucose Starvation. Metabolites 2017; 7:metabo7040063. [PMID: 29186773 PMCID: PMC5746743 DOI: 10.3390/metabo7040063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/19/2017] [Accepted: 11/21/2017] [Indexed: 11/17/2022] Open
Abstract
Proteolysis is essential for all living organisms to maintain the protein homeostasis and to adapt to changing environmental conditions. ClpP is the main protease in Bacillus subtilis, and forms complexes with different Clp ATPases. These complexes play crucial roles during heat stress, but also in sporulation or cell morphology. Especially enzymes of cell wall-, amino acid-, and nucleic acid biosynthesis are known substrates of the protease ClpP during glucose starvation. The aim of this study was to analyze the influence of a clpP mutation on the metabolism in different growth phases and to search for putative new ClpP substrates. Therefore, B. subtilis 168 cells and an isogenic ∆clpP mutant were cultivated in a chemical defined medium, and the metabolome was analyzed by a combination of 1H-NMR, HPLC-MS, and GC-MS. Additionally, the cell morphology was investigated by electron microscopy. The clpP mutant showed higher levels of most glycolytic metabolites, the intermediates of the citric acid cycle, amino acids, and peptidoglycan precursors when compared to the wild-type. A strong secretion of overflow metabolites could be detected in the exo-metabolome of the clpP mutant. Furthermore, a massive increase was observed for the teichoic acid metabolite CDP-glycerol in combination with a swelling of the cell wall. Our results show a recognizable correlation between the metabolome and the corresponding proteome data of B. subtilisclpP mutant. Moreover, our results suggest an influence of ClpP on Tag proteins that are responsible for teichoic acids biosynthesis.
Collapse
Affiliation(s)
- Daniel Schultz
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany;
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, 17487 Greifswald, Germany;
| | - Ulf Gerth
- Institute of Microbiology, University of Greifswald, 17487 Greifswald, Germany;
| | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany;
| |
Collapse
|
28
|
Sun L, Zhang P, Qu T, Chen Y, Hua X, Shi K, Yu Y. Identification of Novel Conjugative Plasmids with Multiple Copies of fosB that Confer High-Level Fosfomycin Resistance to Vancomycin-Resistant Enterococci. Front Microbiol 2017; 8:1541. [PMID: 28861056 PMCID: PMC5559704 DOI: 10.3389/fmicb.2017.01541] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/31/2017] [Indexed: 12/24/2022] Open
Abstract
To further characterize the fosB-carrying plasmids of 19 vancomycin-resistant enterococci, the complete sequences of the fosB- and vanA-containing plasmids of Enterococcus faecium (pEMA120) and E. avium (pEA19081) were obtained by single-molecule, real-time sequencing. We found that these two plasmids are essentially identical (99.99% nucleotide sequence identity), which proved the possibility of interspecies transmission. Comparative analysis of the plasmids revealed that the backbone of pEMA120 is 99% similar to a conjugative fosB-negative E. faecium plasmid, pZB18. There is a traE disrupted in the transfer region of pEMA120, in comparison to pZB18 with an intact traE. The difference of their transfer frequencies between pEMA120 and pZB18 suggests this interruption of traE might affect conjugative transfer. Two copies of the fosB gene linked to a tnpA gene, forming an ISL3-like transposon, were found at separate locations within pEMA120, which had not been reported previously. These two fosB-carrying transposons were confirmed to form circular intermediates by inverse PCR. The hybridization of plasmid DNA digested by BsaI, having restriction site within the fosB sequence, demonstrated that the presence of multiple copies of fosB per plasmid is common. The total copy number of the fosB gene as revealed by qRT-PCR did not correlate with fosfomycin MICs or growth rates at sub-MICs of fosfomycin in different transconjugants. From susceptibility tests, the fosB gene, regardless of the copy number, conferred high fosfomycin MICs that ranged from 16384 to 65536 μg/ml. This first complete nucleotide sequence of a plasmid carrying two copies of fosB in VRE suggests that the fosB gene can transfer to multiple loci of plasmids by the ISL3 family transposase TnpA, possibly in the form of circular intermediates, leading to the dissemination of high fosfomycin resistance in VRE.
Collapse
Affiliation(s)
- Lingyan Sun
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| | - Ping Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| | - Tingting Qu
- State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang UniversityHangzhou, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| | - Keren Shi
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang UniversityHangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang ProvinceHangzhou, China
| |
Collapse
|
29
|
Structural insights into the regulation of Bacillus subtilis SigW activity by anti-sigma RsiW. PLoS One 2017; 12:e0174284. [PMID: 28319136 PMCID: PMC5358783 DOI: 10.1371/journal.pone.0174284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/06/2017] [Indexed: 11/19/2022] Open
Abstract
Bacillus subtilis SigW is localized to the cell membrane and is inactivated by the tight interaction with anti-sigma RsiW under normal growth conditions. Whereas SigW is discharged from RsiW binding and thus initiates the transcription of its regulon under diverse stress conditions such as antibiotics and alkaline shock. The release and activation of SigW in response to extracytoplasmic signals is induced by the regulated intramembrane proteolysis of RsiW. As a ZAS (Zinc-containing anti-sigma) family protein, RsiW has a CHCC zinc binding motif, which implies that its anti-sigma activity may be regulated by the state of zinc coordination in addition to the proteolytic cleavage of RsiW. To understand the regulation mode of SigW activity by RsiW, we determined the crystal structures of SigW in complex with the cytoplasmic domain of RsiW, and compared the conformation of the CHCC motif in the reduced/zinc binding and the oxidized states. The structures revealed that RsiW inhibits the promoter binding of SigW by interacting with the surface groove of SigW. The interaction between SigW and RsiW is not disrupted by the oxidation of the CHCC motif in RsiW, suggesting that SigW activity might not be regulated by the zinc coordination states of the CHCC motif.
Collapse
|
30
|
Cai Y, Chandrangsu P, Gaballa A, Helmann JD. Lack of formylated methionyl-tRNA has pleiotropic effects on Bacillus subtilis. MICROBIOLOGY-SGM 2017; 163:185-196. [PMID: 27983482 DOI: 10.1099/mic.0.000413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Bacteria initiate translation using a modified amino acid, N-formylmethionine (fMet), adapted specifically for this function. Most proteins are processed co-translationally by peptide deformylase (PDF) to remove this modification. Although PDF activity is essential in WT cells and is the target of the antibiotic actinonin, bypass mutations in the fmt gene that eliminate the formylation of Met-tRNAMet render PDF dispensable. The extent to which the emergence of fmt bypass mutations might compromise the therapeutic utility of actinonin is determined, in part, by the effects of these bypass mutations on fitness. Here, we characterize the phenotypic consequences of an fmt null mutation in the model organism Bacillus subtilis. An fmt null mutant is defective for several post-exponential phase adaptive programmes including antibiotic resistance, biofilm formation, swarming and swimming motility and sporulation. In addition, a survey of well-characterized stress responses reveals an increased sensitivity to metal ion excess and oxidative stress. These diverse phenotypes presumably reflect altered synthesis or stability of key proteins involved in these processes.
Collapse
Affiliation(s)
- Yanfei Cai
- Department of Soil Science, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China.,Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Pete Chandrangsu
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Ahmed Gaballa
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
31
|
Woods EC, McBride SM. Regulation of antimicrobial resistance by extracytoplasmic function (ECF) sigma factors. Microbes Infect 2017; 19:238-248. [PMID: 28153747 DOI: 10.1016/j.micinf.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 11/27/2022]
Abstract
Extracytoplasmic function (ECF) sigma factors are a subfamily of σ70 sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens.
Collapse
Affiliation(s)
- Emily C Woods
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA.
| |
Collapse
|
32
|
Critical Minireview: The Fate of tRNA Cys during Oxidative Stress in Bacillus subtilis. Biomolecules 2017; 7:biom7010006. [PMID: 28117687 PMCID: PMC5372718 DOI: 10.3390/biom7010006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 12/15/2022] Open
Abstract
Oxidative stress occurs when cells are exposed to elevated levels of reactive oxygen species that can damage biological molecules. One bacterial response to oxidative stress involves disulfide bond formation either between protein thiols or between protein thiols and low-molecular-weight (LMW) thiols. Bacillithiol was recently identified as a major low-molecular-weight thiol in Bacillus subtilis and related Firmicutes. Four genes (bshA, bshB1, bshB2, and bshC) are involved in bacillithiol biosynthesis. The bshA and bshB1 genes are part of a seven-gene operon (ypjD), which includes the essential gene cca, encoding CCA-tRNA nucleotidyltransferase. The inclusion of cca in the operon containing bacillithiol biosynthetic genes suggests that the integrity of the 3′ terminus of tRNAs may also be important in oxidative stress. The addition of the 3′ terminal CCA sequence by CCA-tRNA nucleotidyltransferase to give rise to a mature tRNA and functional molecules ready for aminoacylation plays an essential role during translation and expression of the genetic code. Any defects in these processes, such as the accumulation of shorter and defective tRNAs under oxidative stress, might exert a deleterious effect on cells. This review summarizes the physiological link between tRNACys regulation and oxidative stress in Bacillus.
Collapse
|
33
|
Abstract
The treatment of bacterial infections suffers from two major problems: spread of multidrug-resistant (MDR) or extensively drug-resistant (XDR) pathogens and lack of development of new antibiotics active against such MDR and XDR bacteria. As a result, physicians have turned to older antibiotics, such as polymyxins, tetracyclines, and aminoglycosides. Lately, due to development of resistance to these agents, fosfomycin has gained attention, as it has remained active against both Gram-positive and Gram-negative MDR and XDR bacteria. New data of higher quality have become available, and several issues were clarified further. In this review, we summarize the available fosfomycin data regarding pharmacokinetic and pharmacodynamic properties, the in vitro activity against susceptible and antibiotic-resistant bacteria, mechanisms of resistance and development of resistance during treatment, synergy and antagonism with other antibiotics, clinical effectiveness, and adverse events. Issues that need to be studied further are also discussed.
Collapse
|
34
|
Helmann JD. Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope. Curr Opin Microbiol 2016; 30:122-132. [PMID: 26901131 DOI: 10.1016/j.mib.2016.02.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/29/2016] [Accepted: 02/02/2016] [Indexed: 01/20/2023]
Abstract
Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σ(W) is most closely associated with membrane-active agents, σ(X) with cationic antimicrobial peptide resistance, and σ(V) with resistance to lysozyme. Here, I highlight the role of the σ(M) regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes. Studies of these cell envelope stress responses provide insights into how bacteria acclimate to the presence of antibiotics.
Collapse
Affiliation(s)
- John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
35
|
Chekan JR, Cogan DP, Nair SK. Molecular Basis for Resistance Against Phosphonate Antibiotics and Herbicides. MEDCHEMCOMM 2016; 7:28-36. [PMID: 26811741 PMCID: PMC4723106 DOI: 10.1039/c5md00351b] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Research in recent years have illuminated data on the mechanisms and targets of phosphonic acid antibiotics and herbicides, including fosfomycin, glyphosate, fosmidomycin and FR900098. Here we review the current state of knowledge of the structural and biochemical characterization of resistance mechanisms against these bioactive natural products. Advances in the understanding of these resistance determinants have spurred knowledge-based campaigns aimed towards the design of derivatives that retain biological activity but are less prone to tolerance.
Collapse
Affiliation(s)
- Jonathan R. Chekan
- Department of Biochemistry, University of Illinois at Urbana Champaign, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana Champaign, USA
| | - Dillon P. Cogan
- Department of Biochemistry, University of Illinois at Urbana Champaign, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana Champaign, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana Champaign, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana Champaign, USA
- Institute for Genomic Biology, University of Illinois at Urbana Champaign, USA
| |
Collapse
|
36
|
Perera VR, Newton GL, Pogliano K. Bacillithiol: a key protective thiol in Staphylococcus aureus. Expert Rev Anti Infect Ther 2015; 13:1089-107. [PMID: 26184907 DOI: 10.1586/14787210.2015.1064309] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacillithiol is a low-molecular-weight thiol analogous to glutathione and is found in several Firmicutes, including Staphylococcus aureus. Since its discovery in 2009, bacillithiol has been a topic of interest because it has been found to contribute to resistance during oxidative stress and detoxification of electrophiles, such as the antibiotic fosfomycin, in S. aureus. The rapid increase in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to available therapeutic agents is a great health concern, and many research efforts are focused on identifying new drugs and targets to combat this organism. This review describes the discovery of bacillithiol, studies that have elucidated the physiological roles of this molecule in S. aureus and other Bacilli, and the contribution of bacillithiol to S. aureus fitness during pathogenesis. Additionally, the bacillithiol biosynthesis pathway is evaluated as a novel drug target that can be utilized in combination with existing therapies to treat S. aureus infections.
Collapse
Affiliation(s)
- Varahenage R Perera
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, Natural Sciences Building 4113, La Jolla, CA 92093-0377, USA
| | | | | |
Collapse
|
37
|
Thompson MK, Keithly ME, Sulikowski GA, Armstrong RN. Diversity in fosfomycin resistance proteins. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.pisc.2014.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
38
|
Chang CM, Chern J, Chen MY, Huang KF, Chen CH, Yang YL, Wu SH. Avenaciolides: Potential MurA-Targeted Inhibitors Against Peptidoglycan Biosynthesis in Methicillin-Resistant Staphylococcus aureus (MRSA). J Am Chem Soc 2014; 137:267-75. [DOI: 10.1021/ja510375f] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Ming-Yi Chen
- General
Education Center, National Taipei University of Nursing and Health Sciences, Taipei 112, Taiwan
| | | | | | | | | |
Collapse
|
39
|
Chen C, Xu X, Qu T, Yu Y, Ying C, Liu Q, Guo Q, Hu F, Zhu D, Li G, Wang M. Prevalence of the fosfomycin-resistance determinant, fosB3, in Enterococcus faecium clinical isolates from China. J Med Microbiol 2014; 63:1484-1489. [PMID: 25102907 DOI: 10.1099/jmm.0.077701-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In order to investigate the prevalence of fosfomycin-resistance (fos) determinants in Enterococcus faecium, clinical strains were collected from hospitals throughout China between January 2008 and December 2009. Antimicrobial susceptibility testing was performed, after which the fos genes in all isolates and van genes in vancomycin-resistant isolates were characterized by PCR and sequencing. Conjugation experiments were carried out with fosB-positive E. faecium, DNA fragments flanking the fosB3 gene were sequenced and the genetic environment of fosB3 was analysed. Fosfomycin-resistant E. faecium (FREF) strains were characterized further by multilocus sequence typing (MLST) and PFGE. Among 145 E. faecium clinical isolates, 10 were resistant to fosfomycin with MICs >1024 mg l−1 including six vancomycin-resistant strains of which five were vanA-positive and the sixth vanM-positive. All ten FREF strains harboured the fosB3 gene. Fosfomycin resistance and fosB3 could be transferred by conjugation from nine isolates. The fosB3 and tnpA genes were located in a circular DNA intermediate in all FREF strains and reversely inserted into vanA transposon Tn1546 in four vanA-positive FREF isolates. Ten different PFGE types and seven MLST types were found among the ten fosB3-positive isolates, while all strains belonged to the common clonal complex CC17. In conclusion, the transferable fosfomycin-resistance determinant fosB3 plays an important role in E. faecium resistance to fosfomycin in China.
Collapse
Affiliation(s)
- Chunhui Chen
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Tingting Qu
- First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, PR China
| | - Yunsong Yu
- First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, PR China
| | - Chunmei Ying
- Department of Clinical Laboratory, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, PR China
| | - Qinzhong Liu
- Department of Clinical Laboratory, Shanghai First People’s Hospital, Shanghai Jiaotong University, Shanghai 200080, PR China
| | - Qinglan Guo
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Demei Zhu
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Guanghui Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| | - Minggui Wang
- Institute of Antibiotics, Huashan Hospital, Fudan University, and Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai 200040, PR China
| |
Collapse
|
40
|
Perera VR, Newton GL, Parnell JM, Komives EA, Pogliano K. Purification and characterization of the Staphylococcus aureus bacillithiol transferase BstA. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1840:2851-61. [PMID: 24821014 PMCID: PMC4802972 DOI: 10.1016/j.bbagen.2014.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Gram-positive bacteria in the phylum Firmicutes synthesize the low molecular weight thiol bacillithiol rather than glutathione or mycothiol. The bacillithiol transferase YfiT from Bacillus subtilis was identified as a new member of the recently discovered DinB/YfiT-like Superfamily. Based on structural similarity using the Superfamily program, we have determined 30 of 31 Staphylococcus aureus strains encode a single bacillithiol transferase from the DinB/YfiT-like Superfamily, while the remaining strain encodes two proteins. METHODS We have cloned, purified, and confirmed the activity of a recombinant bacillithiol transferase (henceforth called BstA) encoded by the S. aureus Newman ORF NWMN_2591. Moreover, we have studied the saturation kinetics and substrate specificity of this enzyme using in vitro biochemical assays. RESULTS BstA was found to be active with the co-substrate bacillithiol, but not with other low molecular weight thiols tested. BstA catalyzed bacillithiol conjugation to the model substrates monochlorobimane, 1-chloro-2,4-dinitrobenzene, and the antibiotic cerulenin. Several other molecules, including the antibiotic rifamycin S, were found to react directly with bacillithiol, but the addition of BstA did not enhance the rate of reaction. Furthermore, cells growing in nutrient rich medium exhibited low BstA activity. CONCLUSIONS BstA is a bacillithiol transferase from S. aureus that catalyzes the detoxification of cerulenin. Additionally, we have determined that bacillithiol itself might be capable of directly detoxifying electrophilic molecules. GENERAL SIGNIFICANCE BstA is an active bacillithiol transferase from S. aureus Newman and is the first DinB/YfiT-like Superfamily member identified from this organism. Interestingly, BstA is highly divergent from B. subtilis YfiT.
Collapse
Affiliation(s)
- Varahenage R Perera
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377
| | - Gerald L Newton
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377
| | - Jonathan M Parnell
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0378
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0378
| | - Kit Pogliano
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377.
| |
Collapse
|
41
|
Mutations in the primary sigma factor σA and termination factor rho that reduce susceptibility to cell wall antibiotics. J Bacteriol 2014; 196:3700-11. [PMID: 25112476 DOI: 10.1128/jb.02022-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Combinations of glycopeptides and β-lactams exert synergistic antibacterial activity, but the evolutionary mechanisms driving resistance to both antibiotics remain largely unexplored. By repeated subculturing with increasing vancomycin (VAN) and cefuroxime (CEF) concentrations, we isolated an evolved strain of the model bacterium Bacillus subtilis with reduced susceptibility to both antibiotics. Whole-genome sequencing revealed point mutations in genes encoding the major σ factor of RNA polymerase (sigA), a cell shape-determining protein (mreB), and the ρ termination factor (rho). Genetic-reconstruction experiments demonstrated that the G-to-C substitution at position 336 encoded by sigA (sigA(G336C)), in the domain that recognizes the -35 promoter region, is sufficient to reduce susceptibility to VAN and works cooperatively with the rho(G56C) substitution to increase CEF resistance. Transcriptome analyses revealed that the sigA(G336C) substitution has wide-ranging effects, including elevated expression of the general stress σ factor (σ(B)) regulon, which is required for CEF resistance, and decreased expression of the glpTQ genes, which leads to fosfomycin (FOS) resistance. Our findings suggest that mutations in the core transcriptional machinery may facilitate the evolution of resistance to multiple cell wall antibiotics.
Collapse
|
42
|
Thompson MK, Keithly ME, Goodman MC, Hammer ND, Cook PD, Jagessar KL, Harp J, Skaar EP, Armstrong RN. Structure and function of the genomically encoded fosfomycin resistance enzyme, FosB, from Staphylococcus aureus. Biochemistry 2014; 53:755-65. [PMID: 24447055 PMCID: PMC3985756 DOI: 10.1021/bi4015852] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
![]()
The
Gram-positive pathogen Staphylococcus aureus is a
leading cause of global morbidity and mortality. Like many
multi-drug-resistant organisms, S. aureus contains
antibiotic-modifying enzymes that facilitate resistance to a multitude
of antimicrobial compounds. FosB is a Mn2+-dependent fosfomycin-inactivating
enzyme found in S. aureus that catalyzes nucleophilic
addition of either l-cysteine (l-Cys) or bacillithiol
(BSH) to the antibiotic, resulting in a modified compound with no
bactericidal properties. The three-dimensional X-ray crystal structure
of FosB from S. aureus (FosBSa) has been determined to a resolution of 1.15 Å. Cocrystallization
of FosBSa with either l-Cys or
BSH results in a disulfide bond between the exogenous thiol and the
active site Cys9 of the enzyme. An analysis of the structures suggests
that a highly conserved loop region of the FosB enzymes must change
conformation to bind fosfomycin. While two crystals of FosBSa contain Zn2+ in the active site, kinetic
analyses of FosBSa indicated that the
enzyme is inhibited by Zn2+ for l-Cys transferase
activity and only marginally active for BSH transferase activity.
Fosfomycin-treated disk diffusion assays involving S. aureus Newman and the USA300 JE2 methicillin-resistant S. aureus demonstrate a marked increase in the sensitivity of the organism
to the antibiotic in either the BSH or FosB null strains, indicating
that both are required for survival of the organism in the presence
of the antibiotic. This work identifies FosB as a primary fosfomycin-modifying
pathway of S. aureus and establishes the enzyme as
a potential therapeutic target for increased efficacy of fosfomycin
against the pathogen.
Collapse
Affiliation(s)
- Matthew K Thompson
- Department of Biochemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Thompson MK, Keithly ME, Harp J, Cook PD, Jagessar KL, Sulikowski GA, Armstrong RN. Structural and chemical aspects of resistance to the antibiotic fosfomycin conferred by FosB from Bacillus cereus. Biochemistry 2013; 52:7350-62. [PMID: 24004181 DOI: 10.1021/bi4009648] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fosfomycin resistance enzymes, FosB, from Gram-positive organisms, are M(2+)-dependent thiol tranferases that catalyze nucleophilic addition of either L-cysteine (L-Cys) or bacillithiol (BSH) to the antibiotic, resulting in a modified compound with no bacteriacidal properties. Here we report the structural and functional characterization of FosB from Bacillus cereus (FosB(Bc)). The overall structure of FosB(Bc), at 1.27 Å resolution, reveals that the enzyme belongs to the vicinal oxygen chelate (VOC) superfamily. Crystal structures of FosB(Bc) cocrystallized with fosfomycin and a variety of divalent metals, including Ni(2+), Mn(2+), Co(2+), and Zn(2+), indicate that the antibiotic coordinates to the active site metal center in an orientation similar to that found in the structurally homologous manganese-dependent fosfomycin resistance enzyme, FosA. Surface analysis of the FosB(Bc) structures show a well-defined binding pocket and an access channel to C1 of fosfomycin, the carbon to which nucleophilic addition of the thiol occurs. The pocket and access channel are appropriate in size and shape to accommodate L-Cys or BSH. Further investigation of the structures revealed that the fosfomycin molecule, anchored by the metal, is surrounded by a cage of amino acids that hold the antibiotic in an orientation such that C1 is centered at the end of the solvent channel, positioning the compound for direct nucleophilic attack by the thiol substrate. In addition, the structures of FosB(Bc) in complex with the L-Cys-fosfomycin product (1.55 Å resolution) and in complex with the bacillithiol-fosfomycin product (1.77 Å resolution) coordinated to a Mn(2+) metal in the active site have been determined. The L-Cys moiety of either product is located in the solvent channel, where the thiol has added to the backside of fosfomycin C1 located at the end of the channel. Concomitant kinetic analyses of FosB(Bc) indicated that the enzyme has a preference for BSH over L-Cys when activated by Mn(2+) and is inhibited by Zn(2+). The fact that Zn(2+) is an inhibitor of FosB(Bc) was used to obtain a ternary complex structure of the enzyme with both fosfomycin and L-Cys bound.
Collapse
Affiliation(s)
- Matthew K Thompson
- Department of Biochemistry, Vanderbilt University , Nashville, Tennessee 37232, United States
| | | | | | | | | | | | | |
Collapse
|
44
|
Reducing the Level of Undecaprenyl Pyrophosphate Synthase Has Complex Effects on Susceptibility to Cell Wall Antibiotics. Antimicrob Agents Chemother 2013; 57:4267-4275. [PMID: 23796923 DOI: 10.1128/aac.00794-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/14/2013] [Indexed: 01/09/2023] Open
Abstract
Undecaprenyl pyrophosphate synthase (UppS) catalyzes the formation of the C55 lipid carrier (UPP) that is essential for bacterial peptidoglycan biosynthesis. We selected here a vancomycin (VAN)-resistant derivative of Bacillus subtilis W168 that contains a single-point mutation in the ribosome-binding site of the uppS gene designated uppS1 Genetic reconstruction experiments demonstrate that the uppS1 allele is sufficient to confer low-level VAN resistance and causes reduced UppS translation. The decreased level of UppS renders B. subtilis slightly more susceptible to many late-acting cell wall antibiotics, including β-lactams, but significantly more resistant to fosfomycin and d-cycloserine, antibiotics that interfere with the very early steps of cell wall synthesis. We further show that the uppS1 allele leads to slightly elevated expression of the σM regulon, possibly helping to compensate for the stress caused by a decrease in UPP levels. Notably, the uppS1 mutation increases resistance to VAN, fosfomycin, and d-cycloserine in wild-type cells, but this effect is greatly reduced or eliminated in a sigM mutant background. Our findings suggest that, although UppS is an attractive antibacterial target, incomplete inhibition of UppS function may lead to increased resistance to some cell wall-active antibiotics.
Collapse
|
45
|
Mechanistic studies of FosB: a divalent-metal-dependent bacillithiol-S-transferase that mediates fosfomycin resistance in Staphylococcus aureus. Biochem J 2013; 451:69-79. [PMID: 23256780 DOI: 10.1042/bj20121541] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
FosB is a divalent-metal-dependent thiol-S-transferase implicated in fosfomycin resistance among many pathogenic Gram-positive bacteria. In the present paper, we describe detailed kinetic studies of FosB from Staphylococcus aureus (SaFosB) that confirm that bacillithiol (BSH) is its preferred physiological thiol substrate. SaFosB is the first to be characterized among a new class of enzyme (bacillithiol-S-transferases), which, unlike glutathione transferases, are distributed among many low-G+C Gram-positive bacteria that use BSH instead of glutathione as their major low-molecular-mass thiol. The K(m) values for BSH and fosfomycin are 4.2 and 17.8 mM respectively. Substrate specificity assays revealed that the thiol and amino groups of BSH are essential for activity, whereas malate is important for SaFosB recognition and catalytic efficiency. Metal activity assays indicated that Mn(2+) and Mg(2+) are likely to be the relevant cofactors under physiological conditions. The serine analogue of BSH (BOH) is an effective competitive inhibitor of SaFosB with respect to BSH, but uncompetitive with respect to fosfomycin. Coupled with NMR characterization of the reaction product (BS-fosfomycin), this demonstrates that the SaFosB-catalysed reaction pathway involves a compulsory ordered binding mechanism with fosfomycin binding first followed by BSH which then attacks the more sterically hindered C-1 carbon of the fosfomycin epoxide. Disruption of BSH biosynthesis in S. aureus increases sensitivity to fosfomycin. Together, these results indicate that SaFosB is a divalent-metal-dependent bacillithiol-S-transferase that confers fosfomycin resistance on S. aureus.
Collapse
|
46
|
Castañeda-García A, Blázquez J, Rodríguez-Rojas A. Molecular Mechanisms and Clinical Impact of Acquired and Intrinsic Fosfomycin Resistance. Antibiotics (Basel) 2013; 2:217-36. [PMID: 27029300 PMCID: PMC4790336 DOI: 10.3390/antibiotics2020217] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 11/16/2022] Open
Abstract
Bacterial infections caused by antibiotic-resistant isolates have become a major health problem in recent years, since they are very difficult to treat, leading to an increase in morbidity and mortality. Fosfomycin is a broad-spectrum bactericidal antibiotic that inhibits cell wall biosynthesis in both Gram-negative and Gram-positive bacteria. This antibiotic has a unique mechanism of action and inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme, MurA. Fosfomycin has been used successfully for the treatment of urinary tract infections for a long time, but the increased emergence of antibiotic resistance has made fosfomycin a suitable candidate for the treatment of infections caused by multidrug-resistant pathogens, especially in combination with other therapeutic partners. The acquisition of fosfomycin resistance could threaten the reintroduction of this antibiotic for the treatment of bacterial infection. Here, we analyse the mechanism of action and molecular mechanisms for the development of fosfomycin resistance, including the modification of the antibiotic target, reduced antibiotic uptake and antibiotic inactivation. In addition, we describe the role of each pathway in clinical isolates.
Collapse
Affiliation(s)
- Alfredo Castañeda-García
- Genome Damage and Stability Centre, University of Sussex, Falmer, Science Park Road, Brighton, East Sussex BN1 9RQ, UK.
| | - Jesús Blázquez
- Centro Nacional de Biotecnología (CSIC), Departamento de Biotecnología Microbiana, Calle Darwin 3, 28049 Madrid, Spain.
| | | |
Collapse
|
47
|
Liao RZ, Thiel W. Determinants of Regioselectivity and Chemoselectivity in Fosfomycin Resistance Protein FosA from QM/MM Calculations. J Phys Chem B 2013; 117:1326-36. [DOI: 10.1021/jp4002719] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Rong-Zhen Liao
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany
| |
Collapse
|
48
|
A mutation of the RNA polymerase β' subunit (rpoC) confers cephalosporin resistance in Bacillus subtilis. Antimicrob Agents Chemother 2012; 57:56-65. [PMID: 23070162 DOI: 10.1128/aac.01449-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In bacteria, mutations affecting the major catalytic subunits of RNA polymerase (encoded by rpoB and rpoC) emerge in response to a variety of selective pressures. Here we isolated a Bacillus subtilis strain with high-level resistance to cefuroxime (CEF). Whole-genome resequencing revealed only one missense mutation affecting an invariant residue in close proximity to the C-terminal DNA-binding domain of RpoC (G1122D). Genetic reconstruction experiments demonstrate that this substitution is sufficient to confer CEF resistance. The G1122D mutation leads to elevated expression of stress-responsive regulons, including those of extracytoplasmic function (ECF) σ factors (σ(M), σ(W), and σ(X)) and the general stress σ factor (σ(B)). The increased CEF resistance of the rpoC(G1122D) strain is lost in the sigM rpoC(G1122D) double mutant, consistent with a major role for σ(M) in CEF resistance. However, a sigM mutant is very sensitive to CEF, and this sensitivity is still reduced by the G1122D mutation, suggesting that other regulatory effects are also important. Indeed, the ability of the G1122D mutation to increase CEF resistance is further reduced in a triple mutant strain lacking three ECF σ factors (σ(M), σ(W), and σ(X)), which are known from prior studies to control overlapping sets of genes. Collectively, our findings highlight the ability of mutations in RNA polymerase to confer antibiotic resistance by affecting the activity of alternative σ factors that control cell envelope stress-responsive regulons.
Collapse
|
49
|
Lamers AP, Keithly ME, Kim K, Cook PD, Stec DF, Hines KM, Sulikowski GA, Armstrong RN. Synthesis of bacillithiol and the catalytic selectivity of FosB-type fosfomycin resistance proteins. Org Lett 2012; 14:5207-9. [PMID: 23030527 DOI: 10.1021/ol302327t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacillithiol (BSH) has been prepared on the gram scale from the inexpensive starting material, D-glucosamine hydrochloride, in 11 steps and 8-9% overall yield. The BSH was used to survey the substrate and metal-ion selectivity of FosB enzymes from four Gram-positive microorganisms associated with the deactivation of the antibiotic fosfomycin. The in vitro results indicate that the preferred thiol substrate and metal ion for the FosB from Staphylococcus aureus are BSH and Ni(II), respectively. However, the metal-ion selectivity is less distinct with FosB from Bacillus subtilis, Bacillus anthracis, or Bacillus cereus.
Collapse
Affiliation(s)
- Alexander P Lamers
- Department of Chemistry, Vanderbilt University, Vanderbilt Institute of Chemical Biology, Nashville, Tennessee 37235, USA
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Novel L-cysteine-dependent maleylpyruvate isomerase in the gentisate pathway of Paenibacillus sp. strain NyZ101. J Bacteriol 2012; 194:3987-94. [PMID: 22636771 DOI: 10.1128/jb.00050-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glutathione- and mycothiol-dependent maleylpyruvate isomerases are known to be involved, respectively, in gentisate catabolism in Gram-negative and high G+C Gram-positive strains. In the present study, a low-G+C Gram-positive Paenibacillus sp. strain, NyZ101, was isolated and shown to degrade 3-hydroxybenzoate via gentisate. A 6.5-kb fragment containing a conserved region of gentisate 1,2-dioxygenase genes was cloned and sequenced, and four genes (bagKLIX) were shown to encode the enzymes involved in the catabolism to central metabolites of 3-hydroxybenzoate via gentisate. The Bag proteins share moderate identities with the reported enzymes in the 3-hydroxybenzoate catabolism, except BagL that had no obvious homology with any functionally characterized proteins. Recombinant BagL was purified to homogeneity as a His-tagged protein and likely a dimer by gel filtration. BagL was demonstrated to be a novel thiol-dependent maleylpyruvate isomerase catalyzing the isomerization of maleylpyruvate to fumarylpyruvate with L-cysteine, cysteinylglycine, or glutathione, as its cofactor. The K(m) values of these three thiols for BagL were 15.5, 8.4, and 552 μM, respectively. Since cysteine and coenzyme A were reported to be abundant in low-G+C Gram-positive strains, BagL should utilize L-cysteine as its physiological cofactor in vivo. The addition of Ni(2+) increased BagL activity, and site-directed mutagenesis experiments indicated that three conserved histidines in BagL were associated with binding to Ni(2+) ion and were necessary for its enzyme activity. BagL is the first characterized L-cysteine-dependent catabolic enzyme in microbial metabolism and is likely a new and distinct member of DinB family, with a four-helix-bundle topology, as deduced by sequence analysis and homology modeling.
Collapse
|