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Reyes Ruiz VM, Freiberg JA, Weiss A, Green ER, Jobson ME, Felton E, Shaw LN, Chazin WJ, Skaar EP. Coordinated adaptation of Staphylococcus aureus to calprotectin-dependent metal sequestration. mBio 2024; 15:e0138924. [PMID: 38920392 PMCID: PMC11253595 DOI: 10.1128/mbio.01389-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 05/21/2024] [Indexed: 06/27/2024] Open
Abstract
The host protein calprotectin inhibits the growth of a variety of bacterial pathogens through metal sequestration in a process known as "nutritional immunity." Staphylococcus aureus growth is inhibited by calprotectin in vitro, and calprotectin is localized in vivo to staphylococcal abscesses during infection. However, the staphylococcal adaptations that provide defense against nutritional immunity and the role of metal-responsive regulators are not fully characterized. In this work, we define the transcriptional response of S. aureus and the role of the metal-responsive regulators, Zur, Fur, and MntR, in response to metal limitation by calprotectin exposure. Additionally, we identified genes affecting the fitness of S. aureus during metal limitation through a Transposon sequencing (Tn-seq) approach. Loss of function mutations in clpP, which encodes a proteolytic subunit of the ATP-dependent Clp protease, demonstrate reduced fitness of S. aureus to the presence of calprotectin. ClpP contributes to pathogenesis in vivo in a calprotectin-dependent manner. These studies establish a critical role for ClpP to combat metal limitation by calprotectin and reveal the genes required for S. aureus to outcompete the host for metals. IMPORTANCE Staphylococcus aureus is a leading cause of skin and soft tissue infections, bloodstream infections, and endocarditis. Antibiotic treatment failures during S. aureus infections are increasingly prevalent, highlighting the need for novel antimicrobial agents. Metal chelator-based therapeutics have tremendous potential as antimicrobials due to the strict requirement for nutrient metals exhibited by bacterial pathogens. The high-affinity transition metal-binding properties of calprotectin represents a potential therapeutic strategy that functions through metal chelation. Our studies provide a foundation to define mechanisms by which S. aureus combats nutritional immunity and may be useful for the development of novel therapeutics to counter the ability of S. aureus to survive in a metal-limited environment.
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Affiliation(s)
- Valeria M. Reyes Ruiz
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jeffrey A. Freiberg
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Andy Weiss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Erin R. Green
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mary-Elizabeth Jobson
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Emily Felton
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Lindsey N. Shaw
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Walter J. Chazin
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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2
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Hong Y, Mackenzie ES, Firth SJ, Bolton JRF, Stewart LJ, Waldron KJ, Djoko KY. Mis-regulation of Zn and Mn homeostasis is a key phenotype of Cu stress in Streptococcus pyogenes. Metallomics 2023; 15:mfad064. [PMID: 37849243 PMCID: PMC10644519 DOI: 10.1093/mtomcs/mfad064] [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: 08/22/2023] [Accepted: 10/16/2023] [Indexed: 10/19/2023]
Abstract
All bacteria possess homeostastic mechanisms that control the availability of micronutrient metals within the cell. Cross-talks between different metal homeostasis pathways within the same bacterial organism have been reported widely. In addition, there have been previous suggestions that some metal uptake transporters can promote adventitious uptake of the wrong metal. This work describes the cross-talk between Cu and the Zn and Mn homeostasis pathways in Group A Streptococcus (GAS). Using a ∆copA mutant strain that lacks the primary Cu efflux pump and thus traps excess Cu in the cytoplasm, we show that growth in the presence of supplemental Cu promotes downregulation of genes that contribute to Zn or Mn uptake. This effect is not associated with changes in cellular Zn or Mn levels. Co-supplementation of the culture medium with Zn or, to a lesser extent, Mn alleviates key Cu stress phenotypes, namely bacterial growth and secretion of the fermentation end-product lactate. However, neither co-supplemental Zn nor Mn influences cellular Cu levels or Cu availability in Cu-stressed cells. In addition, we provide evidence that the Zn or Mn uptake transporters in GAS do not promote Cu uptake. Together, the results from this study strengthen and extend our previous proposal that mis-regulation of Zn and Mn homeostasis is a key phenotype of Cu stress in GAS.
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Affiliation(s)
- YoungJin Hong
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Eilidh S Mackenzie
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Samantha J Firth
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Jack R F Bolton
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Louisa J Stewart
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Kevin J Waldron
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
- Previous affiliation: Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Karrera Y Djoko
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
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3
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Maharjan RP, Sullivan GJ, Adams F, Shah B, Hawkey J, Delgado N, Semenec L, Dinh H, Li L, Short F, Parkhill J, Paulsen I, Barquist L, Eijkelkamp B, Cain A. DksA is a conserved master regulator of stress response in Acinetobacter baumannii. Nucleic Acids Res 2023; 51:6101-6119. [PMID: 37158230 PMCID: PMC10325922 DOI: 10.1093/nar/gkad341] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 04/11/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023] Open
Abstract
Coordination of bacterial stress response mechanisms is critical for long-term survival in harsh environments for successful host infection. The general and specific stress responses of well-studied Gram-negative pathogens like Escherichia coli are controlled by alternative sigma factors, archetypically RpoS. The deadly hospital pathogen Acinetobacter baumannii is notoriously resistant to environmental stresses, yet it lacks RpoS, and the molecular mechanisms driving this incredible stress tolerance remain poorly defined. Here, using functional genomics, we identified the transcriptional regulator DksA as a master regulator for broad stress protection and virulence in A. baumannii. Transcriptomics, phenomics and in vivo animal studies revealed that DksA controls ribosomal protein expression, metabolism, mutation rates, desiccation, antibiotic resistance, and host colonization in a niche-specific manner. Phylogenetically, DksA was highly conserved and well-distributed across Gammaproteobacteria, with 96.6% containing DksA, spanning 88 families. This study lays the groundwork for understanding DksA as a major regulator of general stress response and virulence in this important pathogen.
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Affiliation(s)
- Ram P Maharjan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Geraldine J Sullivan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Felise G Adams
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Bhumika S Shah
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Jane Hawkey
- Department of Infectious Diseases, Central Clinical School, Monash University, Victoria, Australia
| | - Natasha Delgado
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Lucie Semenec
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Liping Li
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Francesca L Short
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080Würzburg, Germany
- Faculty of Medicine, University of Würzburg, 97080Würzburg, Germany
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
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4
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Varghese BR, Goh KGK, Desai D, Acharya D, Chee C, Sullivan MJ, Ulett GC. Variable resistance to zinc intoxication among Streptococcus agalactiae reveals a novel IS1381 insertion element within the zinc efflux transporter gene czcD. Front Immunol 2023; 14:1174695. [PMID: 37304277 PMCID: PMC10251203 DOI: 10.3389/fimmu.2023.1174695] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/11/2023] [Indexed: 06/13/2023] Open
Abstract
Streptococcus agalactiae, also known as group B Streptococcus, is an important human and animal pathogen. Zinc (Zn) is an essential trace element for normal bacterial physiology but intoxicates bacteria at high concentrations. Molecular systems for Zn detoxification exist in S. agalactiae, however the degree to which Zn detoxification may vary among different S. agalactiae isolates is not clear. We measured resistance to Zn intoxication in a diverse collection of clinical isolates of S. agalactiae by comparing the growth of the bacteria in defined conditions of Zn stress. We found significant differences in the ability of different S. agalactiae isolates to resist Zn intoxication; some strains such as S. agalactiae 18RS21 were able to survive and grow at 3.8-fold higher levels of Zn stress compared to other reference strains such as BM110 (6.4mM vs 1.68mM Zn as inhibitory, respectively). We performed in silico analysis of the available genomes of the S. agalactiae isolates used in this study to examine the sequence of czcD, which encodes an efflux protein for Zn that supports resistance in S. agalactiae. Interestingly, this revealed the presence of a mobile insertion sequence (IS) element, termed IS1381, in the 5' region of czcD in S. agalactiae strain 834, which was hyper-resistant to Zn intoxication. Interrogating a wider collection of S. agalactiae genomes revealed identical placement of IS1381 in czcD in other isolates from the clonal-complex-19 (CC19) 19 lineage. Collectively, these results show a resistance spectrum among S. agalactiae isolates enables survival in varying degrees of Zn stress, and this phenotypic variability has implications for understanding bacterial survival in metal stress.
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Affiliation(s)
- Brian R. Varghese
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Kelvin G. K. Goh
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Devika Desai
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Dhruba Acharya
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Collin Chee
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Matthew J. Sullivan
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Glen C. Ulett
- School of Pharmacy and Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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5
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Ren X, Palmer LD. Acinetobacter Metabolism in Infection and Antimicrobial Resistance. Infect Immun 2023:e0043322. [PMID: 37191522 DOI: 10.1128/iai.00433-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Acinetobacter infections have high rates of mortality due to an increasing incidence of infections by multidrug-resistant (MDR) and extensively-drug-resistant (XDR) strains. Therefore, new therapeutic strategies for the treatment of Acinetobacter infections are urgently needed. Acinetobacter spp. are Gram-negative coccobacilli that are obligate aerobes and can utilize a wide variety of carbon sources. Acinetobacter baumannii is the main cause of Acinetobacter infections, and recent work has identified multiple strategies A. baumannii uses to acquire nutrients and replicate in the face of host nutrient restriction. Some host nutrient sources also serve antimicrobial and immunomodulatory functions. Hence, understanding Acinetobacter metabolism during infection may provide new insights into novel infection control measures. In this review, we focus on the role of metabolism during infection and in resistance to antibiotics and other antimicrobial agents and discuss the possibility that metabolism may be exploited to identify novel targets to treat Acinetobacter infections.
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Affiliation(s)
- Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Lauren D Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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6
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Adaptation of Proteome and Metabolism in Different Haplotypes of Rhodosporidium toruloides during Cu(I) and Cu(II) Stress. Microorganisms 2023; 11:microorganisms11030553. [PMID: 36985127 PMCID: PMC10056549 DOI: 10.3390/microorganisms11030553] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Rhodosporidium toruloides is a carotenogenic, oleogenic yeast that is able to grow in diverse environments. In this study, the proteomic and metabolic responses to copper stress in the two haplotypes IFO0559 and IFO0880 were assessed. 0.5 mM Cu(I) extended the lag phase of both strains significantly, while only a small effect was observed for Cu(II) treatment. Other carotenogenic yeasts such as Rhodotorula mucilaginosa are known to accumulate high amounts of carotenoids as a response to oxidative stress, posed by excess copper ion activity. However, no significant increase in carotenoid accumulation for both haplotypes of R. toruloides after 144 h of 0.5 mM Cu(I) or Cu(II) stress was observed. Yet, an increase in lipid production was detected, when exposed to Cu(II), additionally, proteins related to fatty acid biosynthesis were detected in increased amounts under stress conditions. Proteomic analysis revealed that besides the activation of the enzymatic oxidative stress response, excess copper affected iron–sulfur and zinc-containing proteins and caused proteomic adaptation indicative of copper ion accumulation in the vacuole, mitochondria, and Golgi apparatus.
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7
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Ducret V, Gonzalez D, Perron K. Zinc homeostasis in Pseudomonas. Biometals 2022:10.1007/s10534-022-00475-5. [PMID: 36472780 PMCID: PMC10393844 DOI: 10.1007/s10534-022-00475-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
AbstractIn the genus Pseudomonas, zinc homeostasis is mediated by a complete set of import and export systems, whose expression is precisely controlled by three transcriptional regulators: Zur, CzcR and CadR. In this review, we describe in detail our current knowledge of these systems, their regulation, and the biological significance of zinc homeostasis, taking Pseudomonas aeruginosa as our paradigm. Moreover, significant parts of this overview are dedicated to highlight interactions and cross-regulations between zinc and copper import/export systems, and to shed light, through a review of the literature and comparative genomics, on differences in gene complement and function across the whole Pseudomonas genus. The impact and importance of zinc homeostasis in Pseudomonas and beyond will be discussed throughout this review.
Graphical abstract
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8
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Sheldon JR, Himmel LE, Kunkle DE, Monteith AJ, Maloney KN, Skaar EP. Lipocalin-2 is an essential component of the innate immune response to Acinetobacter baumannii infection. PLoS Pathog 2022; 18:e1010809. [PMID: 36054235 PMCID: PMC9477428 DOI: 10.1371/journal.ppat.1010809] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/15/2022] [Accepted: 08/12/2022] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen and an emerging global health threat. Within healthcare settings, major presentations of A. baumannii include bloodstream infections and ventilator-associated pneumonia. The increased prevalence of ventilated patients during the COVID-19 pandemic has led to a rise in secondary bacterial pneumonia caused by multidrug resistant (MDR) A. baumannii. Additionally, due to its MDR status and the lack of antimicrobial drugs in the development pipeline, the World Health Organization has designated carbapenem-resistant A. baumannii to be its priority critical pathogen for the development of novel therapeutics. To better inform the design of new treatment options, a comprehensive understanding of how the host contains A. baumannii infection is required. Here, we investigate the innate immune response to A. baumannii by assessing the impact of infection on host gene expression using NanoString technology. The transcriptional profile observed in the A. baumannii infected host is characteristic of Gram-negative bacteremia and reveals expression patterns consistent with the induction of nutritional immunity, a process by which the host exploits the availability of essential nutrient metals to curtail bacterial proliferation. The gene encoding for lipocalin-2 (Lcn2), a siderophore sequestering protein, was the most highly upregulated during A. baumannii bacteremia, of the targets assessed, and corresponds to robust LCN2 expression in tissues. Lcn2-/- mice exhibited distinct organ-specific gene expression changes including increased transcription of genes involved in metal sequestration, such as S100A8 and S100A9, suggesting a potential compensatory mechanism to perturbed metal homeostasis. In vitro, LCN2 inhibits the iron-dependent growth of A. baumannii and induces iron-regulated gene expression. To elucidate the role of LCN2 in infection, WT and Lcn2-/- mice were infected with A. baumannii using both bacteremia and pneumonia models. LCN2 was not required to control bacterial growth during bacteremia but was protective against mortality. In contrast, during pneumonia Lcn2-/- mice had increased bacterial burdens in all organs evaluated, suggesting that LCN2 plays an important role in inhibiting the survival and dissemination of A. baumannii. The control of A. baumannii infection by LCN2 is likely multifactorial, and our results suggest that impairment of iron acquisition by the pathogen is a contributing factor. Modulation of LCN2 expression or modifying the structure of LCN2 to expand upon its ability to sequester siderophores may thus represent feasible avenues for therapeutic development against this pathogen. A lack of therapeutic options has prompted the World Health Organization to designate multidrug-resistant Acinetobacter baumannii as its priority critical pathogen for research into new treatment strategies. The mechanisms employed by A. baumannii to cause disease and the host tactics exercised to constrain infection are not fully understood. Here, we further characterize the innate immune response to A. baumannii infection. We identify nutritional immunity, a process where the availability of nutrient metals is exploited to restrain bacterial growth, as being induced during infection. The gene encoding for lipocalin-2 (Lcn2), a protein that can impede iron uptake by bacteria, is highly upregulated in infected mice, and corresponds to robust LCN2 detection in the tissues. We find that LCN2 is crucial to reducing mortality from A. baumannii bacteremia and inhibits dissemination of the pathogen during pneumonia. In wild-type and Lcn2-deficient mice, broader transcriptional profiling reveals expression patterns consistent with the known response to Gram-negative bacteremia. Although the role of LCN2 in infection is likely multifactorial, we find its antimicrobial effects are at least partly exerted by impairing iron acquisition by A. baumannii. Facets of nutritional immunity, such as LCN2, may be exploited as novel therapeutics in combating A. baumannii infection.
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Affiliation(s)
- Jessica R. Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Lauren E. Himmel
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Dillon E. Kunkle
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Andrew J. Monteith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - K. Nichole Maloney
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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9
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Regulatory cross-talk supports resistance to Zn intoxication in Streptococcus. PLoS Pathog 2022; 18:e1010607. [PMID: 35862444 PMCID: PMC9345489 DOI: 10.1371/journal.ppat.1010607] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/02/2022] [Accepted: 05/19/2022] [Indexed: 01/07/2023] Open
Abstract
Metals such as copper (Cu) and zinc (Zn) are important trace elements that can affect bacterial cell physiology but can also intoxicate bacteria at high concentrations. Discrete genetic systems for management of Cu and Zn efflux have been described in several bacterial pathogens, including streptococci. However, insight into molecular cross-talk between systems for Cu and Zn management in bacteria that drive metal detoxification, is limited. Here, we describe a biologically consequential cross-system effect of metal management in group B Streptococcus (GBS) governed by the Cu-responsive copY regulator in response to Zn. RNAseq analysis of wild-type (WT) and copY-deficient GBS subjected to metal stress revealed unique transcriptional links between the systems for Cu and Zn detoxification. We show that the Cu-sensing role of CopY extends beyond Cu and enables CopY to regulate Cu and Zn stress responses that effect changes in gene function for central cellular processes, including riboflavin synthesis. CopY also supported GBS intracellular survival in human macrophages and virulence during disseminated infection in mice. In addition, we show a novel role for CovR in modulating GBS resistance to Zn intoxication. Identification of the Zn resistome of GBS using TraDIS revealed a suite of genes essential for GBS growth in metal stress. Several of the genes identified are novel to systems that support bacterial survival in metal stress and represent a diverse set of mechanisms that underpin microbial metal homeostasis during cell stress. Overall, this study reveals a new and important mechanism of cross-system complexity driven by CopY in bacteria to regulate cellular management of metal stress and survival. Metals, such as Cu and Zn, can be used by the mammalian immune system to target bacterial pathogens for destruction, and consequently, bacteria have evolved discrete genetic systems to enable subversion of this host antimicrobial response. Systems for Cu and Zn homeostasis are well characterized, including transcriptional control elements that sense and respond to metal stress. Here, we discover novel features of metal response systems in Streptococcus, which have broad implications for bacterial pathogenesis and virulence. We show that Streptococcus resists Zn intoxication by utilizing a bona fide Cu regulator, CopY, to manage cellular metal homeostasis, and enable the bacteria to survive stressful conditions. We identify several new genes that confer resistance to Zn intoxication in Streptococcus, including some that have hitherto not been linked to metal ion homeostasis in any bacterial pathogen. Identification of a novel cross-system metal management mechanism exploited by Streptococcus to co-ordinate and achieve metal resistance enhances our understanding of metal ion homeostasis in bacteria and its effect on pathogenesis.
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10
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Yang Q, Olaifa K, Andrew FP, Ajibade PA, Ajunwa OM, Marsili E. Assessment of physiological and electrochemical effects of a repurposed zinc dithiocarbamate complex on Acinetobacter baumannii biofilms. Sci Rep 2022; 12:11701. [PMID: 35810245 PMCID: PMC9271062 DOI: 10.1038/s41598-022-16047-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 07/04/2022] [Indexed: 11/09/2022] Open
Abstract
Acinetobacter baumannii is an infectious agent of global proportion and concern, partly due to its proficiency in development of antibiotic resistance phenotypes and biofilm formation. Dithiocarbamates (DTC) have been identified as possible alternatives to the current antimicrobials. We report here the evaluation of several DTC-metal complexes against A. baumannii planktonic cells and biofilms. Among the DTC-metal complexes and DTCs tested, ZnL1 (N-methyl-1-phenyldithiocarbamato-S,S' Zn(II)), originally designed as an antitumor agent, is effective against biofilm forming A. baumannii. A MIC value of 12.5 µM, comparable to that of Gentamicin (5 µM) was measured for planktonic cells in tryptic soy broth. Spectroscopy, microscopy and biochemical analyses reveal cell membrane degradation and leakage after treatment with ZnL1. Bioelectrochemical analyses show that ZnL1 reduces biofilm formation and decreases extracellular respiration of pre-formed biofilms, as corroborated by microscopic analyses. Due to the affinity of Zn to cells and the metal chelating nature of L1 ligand, we hypothesize ZnL1 could alter metalloprotein functions in the membranes of A. baumannii cells, leading to altered redox balance. Results indicate that the DTC-Zn metal complex is an effective antimicrobial agent against early A. baumannii biofilms under laboratory conditions.
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Affiliation(s)
- Qing Yang
- Biofilm Laboratory, Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Avenue, Nur-Sultan, 01000, Kazakhstan
| | - Kayode Olaifa
- Biofilm Laboratory, Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Avenue, Nur-Sultan, 01000, Kazakhstan
| | - Fartisincha P Andrew
- Department of Science Laboratory Technology, Modibbo Adama University, Yola, Nigeria
| | - Peter A Ajibade
- School of Chemistry and Physics, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Obinna M Ajunwa
- Biofilm Laboratory, Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Avenue, Nur-Sultan, 01000, Kazakhstan.,Department of Microbiology, Modibbo Adama University, Yola, Nigeria
| | - Enrico Marsili
- Biofilm Laboratory, Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, 53 Kabanbay Batyr Avenue, Nur-Sultan, 01000, Kazakhstan.
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11
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Metryka O, Wasilkowski D, Mrozik A. Evaluation of the Effects of Ag, Cu, ZnO and TiO 2 Nanoparticles on the Expression Level of Oxidative Stress-Related Genes and the Activity of Antioxidant Enzymes in Escherichia coli, Bacillus cereus and Staphylococcus epidermidis. Int J Mol Sci 2022; 23:4966. [PMID: 35563357 PMCID: PMC9103769 DOI: 10.3390/ijms23094966] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 12/13/2022] Open
Abstract
Although the molecular response of bacteria exposed to metal nanoparticles (NPs) is intensively studied, many phenomena related to their survival, metal uptake, gene expression and protein production are not fully understood. Therefore, this work aimed to study Ag-NPs, Cu-NPs, ZnO-NPs and TiO2-NPs-induced alterations in the expression level of selected oxidative stress-related genes in connection with the activity of antioxidant enzymes: catalase (CAT), peroxidase (PER) and superoxide dismutase (SOD) in Escherichia coli, Bacillus cereus and Staphylococcus epidermidis. The methodology used included: the extraction of total RNA and cDNA synthesis, the preparation of primers for selected housekeeping and oxidative stress genes, RT-qPCR reaction and the measurements of CAT, PER and SOD activities. It was established that the treatment of E. coli and S. epidermidis with NPs resulted mainly in the down-regulation of targeted genes, whilst the up-regulation of genes was confirmed in B. cereus. The greatest differences in the relative expression levels of tested genes occurred in B. cereus and S. epidermidis treated with TiO2-NPs, while in E. coli, they were observed under ZnO-NPs exposure. The changes found were mostly related to the expression of genes encoding proteins with PER and CAT-like activity. Among NPs, ZnO-NPs and Cu-NPs increased the activity of antioxidants in E. coli and B. cereus. In turn, TiO2-NPs had a major effect on enzymes activity in S. epidermidis. Considering all of the collected results for tested bacteria, it can be emphasised that the impact of NPs on the antioxidant system functioning was dependent on their type and concentration.
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Affiliation(s)
- Oliwia Metryka
- Doctoral School, University of Silesia, Bankowa 14, 40-032 Katowice, Poland
| | - Daniel Wasilkowski
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland;
| | - Agnieszka Mrozik
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland;
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12
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Steimbrüch BA, Sartorio MG, Cortez N, Albanesi D, Lisa MN, Repizo GD. The distinctive roles played by the superoxide dismutases of the extremophile Acinetobacter sp. Ver3. Sci Rep 2022; 12:4321. [PMID: 35279679 PMCID: PMC8918354 DOI: 10.1038/s41598-022-08052-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/28/2022] [Indexed: 11/09/2022] Open
Abstract
Acinetobacter sp. Ver3 is a polyextremophilic strain characterized by a high tolerance to radiation and pro-oxidants. The Ver3 genome comprises the sodB and sodC genes encoding an iron (AV3SodB) and a copper/zinc superoxide dismutase (AV3SodC), respectively; however, the specific role(s) of these genes has remained elusive. We show that the expression of sodB remained unaltered in different oxidative stress conditions whereas sodC was up-regulated in the presence of blue light. Besides, we studied the changes in the in vitro activity of each SOD enzyme in response to diverse agents and solved the crystal structure of AV3SodB at 1.34 Å, one of the highest resolutions achieved for a SOD. Cell fractionation studies interestingly revealed that AV3SodB is located in the cytosol whereas AV3SodC is also found in the periplasm. Consistently, a bioinformatic analysis of the genomes of 53 Acinetobacter species pointed out the presence of at least one SOD type in each compartment, suggesting that these enzymes are separately required to cope with oxidative stress. Surprisingly, AV3SodC was found in an active state also in outer membrane vesicles, probably exerting a protective role. Overall, our multidisciplinary approach highlights the relevance of SOD enzymes when Acinetobacterspp. are confronted with oxidizing agents.
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Affiliation(s)
- Bruno Alejandro Steimbrüch
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Mariana Gabriela Sartorio
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Néstor Cortez
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Daniela Albanesi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo y Esmeralda, S2002LRK, Rosario, Argentina.,Plataforma de Biología Estructural y Metabolómica (PLABEM), Ocampo y Esmeralda, S2002LRK, Rosario, Argentina
| | - María-Natalia Lisa
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Ocampo y Esmeralda, S2002LRK, Rosario, Argentina. .,Plataforma de Biología Estructural y Metabolómica (PLABEM), Ocampo y Esmeralda, S2002LRK, Rosario, Argentina.
| | - Guillermo Daniel Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina.
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13
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Escudero V, Ferreira Sánchez D, Abreu I, Sopeña-Torres S, Makarovsky-Saavedra N, Bernal M, Krämer U, Grolimund D, González-Guerrero M, Jordá L. Arabidopsis thaliana Zn2+-efflux ATPases HMA2 and HMA4 are required for resistance to the necrotrophic fungus Plectosphaerella cucumerina BMM. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:339-350. [PMID: 34463334 DOI: 10.1093/jxb/erab400] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Zinc is an essential nutrient at low concentrations, but toxic at slightly higher ones. It has been proposed that hyperaccumulator plants may use the excess zinc to fend off pathogens and herbivores. However, there is little evidence of a similar response in other plants. Here we show that Arabidopsis thaliana leaves inoculated with the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM) accumulate zinc and manganese at the infection site. Zinc accumulation did not occur in a double mutant in the zinc transporters HEAVY METAL ATPASE2 and HEAVY METAL ATPASE4 (HMA2 and HMA4), which has reduced zinc translocation from roots to shoots. Consistent with a role in plant immunity, expression of HMA2 and HMA4 was up-regulated upon PcBMM inoculation, and hma2hma4 mutants were more susceptible to PcBMM infection. This phenotype was rescued upon zinc supplementation. The increased susceptibility to PcBMM infection was not due to the diminished expression of genes involved in the salicylic acid, ethylene, or jasmonate pathways since they were constitutively up-regulated in hma2hma4 plants. Our data indicate a role of zinc in resistance to PcBMM in plants containing ordinary levels of zinc. This layer of immunity runs in parallel to the already characterized defence pathways, and its removal has a direct effect on resistance to pathogens.
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Affiliation(s)
- Viviana Escudero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
| | - Darío Ferreira Sánchez
- Paul Scherrer Institute, Swiss Light Source, microXAS Beamline Project, CH-5232 Villigen, Switzerland
| | - Isidro Abreu
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
| | - Sara Sopeña-Torres
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
| | - Natalia Makarovsky-Saavedra
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
| | - María Bernal
- Department of Molecular Genetics and Physiology of Plants. Ruhr University Bochum. Universitätstrasse, Bochum, Germany
| | - Ute Krämer
- Department of Molecular Genetics and Physiology of Plants. Ruhr University Bochum. Universitätstrasse, Bochum, Germany
| | - Daniel Grolimund
- Paul Scherrer Institute, Swiss Light Source, microXAS Beamline Project, CH-5232 Villigen, Switzerland
| | - Manuel González-Guerrero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid. 28040 Madrid, Spain
| | - Lucía Jordá
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223. Pozuelo de Alarcón (Madrid), Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid. 28040 Madrid, Spain
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14
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Plasmids Bring Additional Capabilities to Caulobacter Isolates. Curr Microbiol 2022; 79:45. [PMID: 34982248 PMCID: PMC8812328 DOI: 10.1007/s00284-021-02742-z] [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: 02/10/2021] [Accepted: 12/06/2021] [Indexed: 01/07/2023]
Abstract
Caulobacter is a well-studied bacterial genus, but little is known about the plasmids that are found in some wild Caulobacter isolates. We used bioinformatic approaches to identify nine plasmids from seven different Caulobacter strains and grouped them based on their size and the similarity of their repABC, parAB, and mobAB genes. Protein pathway analysis of the genes on the K31p1 and K31p2 plasmids showed many metabolic pathways that would enhance the metabolic versatility of the host strain. In contrast, the CB4 plasmid contained 21 heavy metal resistance genes with the majority coding for proteins that enhance copper resistance. Growth assays of C. henricii CB4 demonstrated increased copper resistance and quantitative PCR showed an increase in the expression of eight heavy metal genes when induced with copper.
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15
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Abstract
The bacterial pathogen Acinetobacter baumannii has emerged as an urgent threat to health care systems. The prevalence of multidrug resistance in this critical human pathogen is closely associated with difficulties in its eradication from the hospital environment and its recalcitrance to treatment during infection. The development of resistance in A. baumannii is in part due to substantial plasticity of its genome, facilitating spontaneous genomic evolution. Many studies have investigated selective pressures imposed by antibiotics on genomic evolution, but the influence of high-abundance bioactive molecules at the host-pathogen interface on mutation and rates of evolution is poorly understood. Here, we studied the roles of host fatty acids in the gain in resistance to common antibiotics. We defined the impact of the polyunsaturated fatty acids arachidonic acid and docosahexaenoic acid on the development of resistance to erythromycin in A. baumannii strain AB5075_UW using a microevolutionary approach. We employed whole-genome sequencing and various phenotypic analyses to characterize microbe-lipid-antibiotic interactions. Cells exposed to erythromycin in the presence of the fatty acids displayed significantly lower rates of development of resistance to erythromycin and, importantly, tetracycline. Subsequent analyses defined diverse means by which host fatty acids influence the mutation rates. This work has highlighted the critical need to consider the roles of host fatty acids in A. baumannii physiology and antimicrobial resistance. Collectively, we have identified a novel means to curb the development of resistance in this critical human pathogen. IMPORTANCE The global distribution of multidrug resistance in A. baumannii has necessitated seeking not only alternative therapeutic approaches but also the means to limit the development of resistance in clinical settings. Highly abundant host bioactive compounds, such as polyunsaturated fatty acids, are readily acquired by A. baumannii during infection and have been illustrated to impact the bacterium's membrane composition and antibiotic resistance. In this work, we show that in vitro supplementation with host polyunsaturated fatty acids reduces the rate at which A. baumannii gains resistance to erythromycin and tetracycline. Furthermore, we discover that the impact on resistance development is closely associated with the primary antimicrobial efflux systems of A. baumannii, which represent one of the major drivers of clinical resistance. Overall, this study emphasizes the potential of host macromolecules in novel approaches to circumvent the difficulties of multidrug resistance during A. baumannii treatment, with fatty acid supplements such as fish oil providing safe and cost-effective ways to enhance host tolerance to bacterial infections.
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16
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The Molecular Basis of Acinetobacter baumannii Cadmium Toxicity and Resistance. Appl Environ Microbiol 2021; 87:e0171821. [PMID: 34495707 DOI: 10.1128/aem.01718-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Acinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, in soil, and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Metal ion homeostasis in the hospital pathogen Acinetobacter baumannii contributes to pathogenesis; however, insights into its metal ion transporters for environmental persistence are lacking. Here, we studied the impact of cadmium stress on A. baumannii. Our functional genomics and independent mutant analyses revealed a primary role for CzcE, a member of the cation diffusion facilitator (CDF) superfamily, in resisting cadmium stress. We also show that the CzcCBA heavy metal efflux system contributes to cadmium efflux. Collectively, these systems provide A. baumannii with a comprehensive cadmium translocation pathway from the cytoplasm to the periplasm and subsequently the extracellular space. Furthermore, analysis of the A. baumannii metallome under cadmium stress showed zinc depletion, as well as copper enrichment, both of which are likely to influence cellular fitness. Overall, this work provides new knowledge on the role of a broad arsenal of membrane transporters in A. baumannii metal ion homeostasis. IMPORTANCE Cadmium toxicity is a widespread problem, yet the interaction of this heavy metal with biological systems is poorly understood. Some microbes have evolved traits to proactively counteract cadmium toxicity, including Acinetobacter baumannii, which is notorious for persisting in harsh environments. Here, we show that A. baumannii utilizes a dedicated cadmium efflux protein in concert with a system that is primarily attuned to zinc efflux to efficiently overcome cadmium stress. The molecular characterization of A. baumannii under cadmium stress revealed how active cadmium efflux plays a key role in preventing the dysregulation of bacterial metal ion homeostasis, which appeared to be a primary means by which cadmium exerts toxicity upon the bacterium.
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17
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Newsome L, Falagán C. The Microbiology of Metal Mine Waste: Bioremediation Applications and Implications for Planetary Health. GEOHEALTH 2021; 5:e2020GH000380. [PMID: 34632243 PMCID: PMC8490943 DOI: 10.1029/2020gh000380] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 05/13/2023]
Abstract
Mine wastes pollute the environment with metals and metalloids in toxic concentrations, causing problems for humans and wildlife. Microorganisms colonize and inhabit mine wastes, and can influence the environmental mobility of metals through metabolic activity, biogeochemical cycling and detoxification mechanisms. In this article we review the microbiology of the metals and metalloids most commonly associated with mine wastes: arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc. We discuss the molecular mechanisms by which bacteria, archaea, and fungi interact with contaminant metals and the consequences for metal fate in the environment, focusing on long-term field studies of metal-impacted mine wastes where possible. Metal contamination can decrease the efficiency of soil functioning and essential element cycling due to the need for microbes to expend energy to maintain and repair cells. However, microbial communities are able to tolerate and adapt to metal contamination, particularly when the contaminant metals are essential elements that are subject to homeostasis or have a close biochemical analog. Stimulating the development of microbially reducing conditions, for example in constructed wetlands, is beneficial for remediating many metals associated with mine wastes. It has been shown to be effective at low pH, circumneutral and high pH conditions in the laboratory and at pilot field-scale. Further demonstration of this technology at full field-scale is required, as is more research to optimize bioremediation and to investigate combined remediation strategies. Microbial activity has the potential to mitigate the impacts of metal mine wastes, and therefore lessen the impact of this pollution on planetary health.
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Affiliation(s)
- Laura Newsome
- Camborne School of Mines and Environment and Sustainability InstituteUniversity of ExeterPenrynUK
| | - Carmen Falagán
- Camborne School of Mines and Environment and Sustainability InstituteUniversity of ExeterPenrynUK
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18
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Zhou H, Gebhardt MJ, Czyz DM, Yao Y, Shuman HA. The gigA/gigB Genes Regulate the Growth, Stress Response, and Virulence of Acinetobacter baumannii ATCC 17978 Strain. Front Microbiol 2021; 12:723949. [PMID: 34421881 PMCID: PMC8371402 DOI: 10.3389/fmicb.2021.723949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/16/2021] [Indexed: 12/03/2022] Open
Abstract
Acinetobacter baumannii is an important pathogen of nosocomial infection. Recently, a group of genes, named “gig” (for Growth in Galleria), have been identified in a contemporary multi-drug resistant clinical isolate of A. baumannii—strain AB5075. Among these so-called gig genes, gigA and gigB were found to promote antibiotic resistance, stress survival, and virulence of AB5075 by interacting with the nitrogen phosphotransferase system (PTSNtr). This study aimed to investigate the roles of gigA/gigB, which appear to comprise a stress-signaling pathway (encoding for an atypical two-component system response regulator and a predicted anti-anti-sigma factor, respectively), and the involvement of ptsP (encoding the Enzyme I component of the PTSNtr) in the growth, stress resistance, and virulence of the widely studied A. baumannii strain ATCC 17978. Genetic analyses of strains harboring mutations of gigA and gigB were performed to investigate the roles of these genes in bacterial growth, stress resistance, evading macrophage defense, and killing of Galleria mellonella larva. In contrast with findings from strain AB5075 where gigA and gigB contribute to aminoglycoside resistance, the data presented herein indicate that the loss of gigA/gigB does not impact antibiotic resistance of strain ATCC 17978. Interestingly, however, we found that deletion of gigA/gigB in the ATCC 17978 background imparts a general growth in laboratory medium and also conferred growth and replication defects within murine macrophages and an inability to kill G. mellonella larvae. Importantly, studies as well as the loss of ptsP restored the phenotypes of the gigA/gigB mutant to that of the wild-type. The data presented herein indicate that in A. baumannii ATCC 17978, the gigA/gigB genes play a key role in both growth and virulence traits, but are dispensable for other stress-resistance survival phenotypes, including aminoglycoside resistance. Our findings thus highlight several similarities and also important differences between the gigA/gigB stress-signaling pathway in two commonly studied isolates of this troublesome pathogen.
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Affiliation(s)
- Hua Zhou
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Microbiology, University of Chicago, Chicago, IL, United States
| | - Michael J Gebhardt
- Department of Microbiology, University of Chicago, Chicago, IL, United States
| | - Daniel M Czyz
- Department of Microbiology, University of Chicago, Chicago, IL, United States.,Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, United States
| | - Yake Yao
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Howard A Shuman
- Department of Microbiology, University of Chicago, Chicago, IL, United States
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19
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Cellular Management of Zinc in Group B Streptococcus Supports Bacterial Resistance against Metal Intoxication and Promotes Disseminated Infection. mSphere 2021; 6:6/3/e00105-21. [PMID: 34011683 PMCID: PMC8265624 DOI: 10.1128/msphere.00105-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Zinc is an essential trace element for normal bacterial physiology but, divergently, can intoxicate bacteria at high concentrations. Here, we define the molecular systems for Zn detoxification in Streptococcus agalactiae, also known as group B streptococcus, and examine the effects of resistance to Zn stress on virulence. We compared the growth of wild-type bacteria and mutants deleted for the Zn exporter, czcD, and the response regulator, sczA, using Zn-stress conditions in vitro Macrophage antibiotic protection assays and a mouse model of disseminated infection were used to assess virulence. Global bacterial transcriptional responses to Zn stress were defined by RNA sequencing and quantitative reverse transcription-PCR. czcD and sczA enabled S. agalactiae to survive Zn stress, with the putative CzcD efflux system activated by SczA. Additional genes activated in response to Zn stress encompassed divalent cation transporters that contribute to regulation of Mn and Fe homeostasis. In vivo, the czcD-sczA Zn management axis supported virulence in the blood, heart, liver, and bladder. Additionally, several genes not previously linked to Zn stress in any bacterium, including, most notably, arcA for arginine deamination, also mediated resistance to Zn stress, representing a novel molecular mechanism of bacterial resistance to metal intoxication. Taken together, these findings show that S. agalactiae responds to Zn stress by sczA regulation of czcD, with additional novel mechanisms of resistance supported by arcA, encoding arginine deaminase. Cellular management of Zn stress in S. agalactiae supports virulence by facilitating bacterial survival in the host during systemic infection.IMPORTANCE Streptococcus agalactiae, also known as group B streptococcus, is an opportunistic pathogen that causes various diseases in humans and animals. This bacterium has genetic systems that enable zinc detoxification in environments of metal stress, but these systems remain largely undefined. Using a combination of genomic, genetic, and cellular assays, we show that this pathogen controls Zn export through CzcD to manage Zn stress and utilizes a system of arginine deamination never previously linked to metal stress responses in bacteria to survive metal intoxication. We show that these systems are crucial for survival of S. agalactiae in vitro during Zn stress and also enhance virulence during systemic infection in mice. These discoveries establish new molecular mechanisms of resistance to metal intoxication in bacteria; we suggest these mechanisms operate in other bacteria as a way to sustain microbial survival under conditions of metal stress, including in host environments.
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20
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Gupta AD, Kavitha E, Singh S, Karthikeyan S. Toxicity mechanism of Cu 2+ ion individually and in combination with Zn 2+ ion in characterizing the molecular changes of Staphylococcus aureus studied using FTIR coupled with chemometric analysis. J Biol Phys 2020; 46:395-414. [PMID: 33237339 PMCID: PMC7719146 DOI: 10.1007/s10867-020-09560-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/08/2020] [Indexed: 10/22/2022] Open
Abstract
Copper and zinc have a high binding affinity with a Staphylococcus aureus bacterial community. This causes a change in the biomolecular composition of S. aureus. Our study aims at understanding the resistance mechanism of Cu and Zn either or in various combinations using FTIR and chemometric techniques. Zn toxicity resulted in a significant change in lipid content (3100-2800 cm-1) compared to Cu. A significant decrease in protein content is observed for Cu treatment in the amide region. The bio-concentration factor shows a higher value for Cu compared to Zn. The increase in band area of carbohydrates moieties 1059 cm-1 shows the secretion of EPS due to Cu toxicity. A significant change in nucleic acid compositions was noted in the region1200-900 cm-1 due to Zn treatment. Secondary structural change in protein shows β sheet formation. The result of the finding shows Cu has greater toxicity than Zn. Further toxicity effects were greatly enhanced for metal mixtures ratio (Cu:2Zn). This shows Zn exhibits synergism effect with Cu. The obtained ROC (receiver operating characteristic) curve area gives good reliability of the experiments. The study attempts to understand the mechanism of toxicity removal of Cu and Zn metal mixtures by bacterial population using FTIR coupled with chemometric techniques. Graphical abstract.
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Affiliation(s)
- Annika Durve Gupta
- Department of Biotechnology, B. K. Birla College, Kalyan, Maharashtra, 421304, India
| | - Esakimuthu Kavitha
- Department of Physics, Dr. MGR Educational and Research Institute, Chennai, Tamil Nadu, 600095, India
| | - Shikha Singh
- Department of Biotechnology, B. K. Birla College, Kalyan, Maharashtra, 421304, India
| | - Sivakumaran Karthikeyan
- Department of Physics, Dr. Ambedkar Government Arts College, Chennai, Tamil Nadu, 600039, India.
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21
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von Pein JB, Stocks CJ, Schembri MA, Kapetanovic R, Sweet MJ. An alloy of zinc and innate immunity: Galvanising host defence against infection. Cell Microbiol 2020; 23:e13268. [PMID: 32975847 DOI: 10.1111/cmi.13268] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
Innate immune cells such as macrophages and neutrophils initiate protective inflammatory responses and engage antimicrobial responses to provide frontline defence against invading pathogens. These cells can both restrict the availability of certain transition metals that are essential for microbial growth and direct toxic concentrations of metals towards pathogens as antimicrobial responses. Zinc is important for the structure and function of many proteins, however excess zinc can be cytotoxic. In recent years, several studies have revealed that innate immune cells can deliver toxic concentrations of zinc to intracellular pathogens. In this review, we discuss the importance of zinc status during infectious disease and the evidence for zinc intoxication as an innate immune antimicrobial response. Evidence for pathogen subversion of this response is also examined. The likely mechanisms, including the involvement of specific zinc transporters that facilitate delivery of zinc by innate immune cells for metal ion poisoning of pathogens are also considered. Precise mechanisms by which excess levels of zinc can be toxic to microorganisms are then discussed, particularly in the context of synergy with other antimicrobial responses. Finally, we highlight key unanswered questions in this emerging field, which may offer new opportunities for exploiting innate immune responses for anti-infective development.
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Affiliation(s)
- Jessica B von Pein
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
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22
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Zhao Q, Liu W, Li Y, Ke M, Qu Q, Yuan W, Pan X, Qian H. Enantioselective effects of imazethapyr residues on Arabidopsis thaliana metabolic profile and phyllosphere microbial communities. J Environ Sci (China) 2020; 93:57-65. [PMID: 32446460 DOI: 10.1016/j.jes.2020.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/04/2020] [Accepted: 03/04/2020] [Indexed: 06/11/2023]
Abstract
Imazethapyr (IM) is a widely used acetolactate synthase-inhibiting chiral herbicide. It has long-term residuals that may be absorbed by the human body through the edible parts of plants, such as vegetable leaves or fruits. Here, we selected a model plant, Arabidopsis thaliana, to determine the effects of R-IM and S-IM on its leaf structure, photosynthetic efficiency, and metabolites, as well as the structures of microorganisms in the phyllosphere, after 7 days of exposure. Our results indicated enantiomeric differences in plant growth between R-IM and S-IM; 133 µg/kg R-IM showed heavier inhibition of photosynthetic efficiency and greater changes to subcellular structure than S-IM. R-IM and S-IM also had different effects on metabolism and leaf microorganisms. S-IM mainly increased lipid compounds and decreased amino acids, while R-IM increased sugar accumulation. The relative abundance of Moraxellaceae human pathogenic bacteria was increased by R-IM treatment, indicating that R-IM treatment may increase leaf surface pathogenic bacteria. Our research provides a new perspective for evaluating the harmfulness of pesticide residues in soil, phyllosphere microbiome changes via the regulation of plant metabolism, and induced pathogenic bacterial accumulation risks.
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Affiliation(s)
- Qianqiu Zhao
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wanyue Liu
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Mingjing Ke
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Qian Qu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Wenting Yuan
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiangliang Pan
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Haifeng Qian
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; College of Environment, Zhejiang University of Technology, Hangzhou 310032, China.
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23
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Stocks CJ, von Pein JB, Curson JEB, Rae J, Phan MD, Foo D, Bokil NJ, Kambe T, Peters KM, Parton RG, Schembri MA, Kapetanovic R, Sweet MJ. Frontline Science: LPS-inducible SLC30A1 drives human macrophage-mediated zinc toxicity against intracellular Escherichia coli. J Leukoc Biol 2020; 109:287-297. [PMID: 32441444 PMCID: PMC7891337 DOI: 10.1002/jlb.2hi0420-160r] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/22/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
TLR-inducible zinc toxicity is an antimicrobial mechanism utilized by macrophages, however knowledge of molecular mechanisms mediating this response is limited. Here, we show that E. coli exposed to zinc stress within primary human macrophages reside in membrane-bound vesicular compartments. Since SLC30A zinc exporters can deliver zinc into the lumen of vesicles, we examined LPS-regulated mRNA expression of Slc30a/SLC30A family members in primary mouse and human macrophages. A number of these transporters were dynamically regulated in both cell populations. In human monocyte-derived macrophages, LPS strongly up-regulated SLC30A1 mRNA and protein expression. In contrast, SLC30A1 was not LPS-inducible in macrophage-like PMA-differentiated THP-1 cells. We therefore ectopically expressed SLC30A1 in these cells, finding that this was sufficient to promote zinc-containing vesicle formation. The response was similar to that observed following LPS stimulation. Ectopically expressed SLC30A1 localized to both the plasma membrane and intracellular zinc-containing vesicles within LPS-stimulated THP-1 cells. Inducible overexpression of SLC30A1 in THP-1 cells infected with the Escherichia coli K-12 strain MG1655 augmented the zinc stress response of intracellular bacteria and promoted clearance. Furthermore, in THP-1 cells infected with an MG1655 zinc stress reporter strain, all bacteria contained within SLC30A1-positive compartments were subjected to zinc stress. Thus, SLC30A1 marks zinc-containing compartments associated with TLR-inducible zinc toxicity in human macrophages, and its ectopic over-expression is sufficient to initiate this antimicrobial pathway in these cells. Finally, SLC30A1 silencing did not compromise E. coli clearance by primary human macrophages, suggesting that other zinc exporters may also contribute to the zinc toxicity response.
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Affiliation(s)
- Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Jessica B von Pein
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - James E B Curson
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia
| | - Minh-Duy Phan
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Darren Foo
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Nilesh J Bokil
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kate M Peters
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
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24
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García V, Herrero-Fresno A, Rodicio R, Felipe-López A, Montero I, Olsen JE, Hensel M, Rodicio MR. A Plasmid-Encoded FetMP-Fls Iron Uptake System Confers Selective Advantages to Salmonella enterica Serovar Typhimurium in Growth under Iron-Restricted Conditions and for Infection of Mammalian Host Cells. Microorganisms 2020; 8:microorganisms8050630. [PMID: 32349391 PMCID: PMC7285068 DOI: 10.3390/microorganisms8050630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/22/2020] [Accepted: 04/25/2020] [Indexed: 12/03/2022] Open
Abstract
The resistance plasmid pUO-StVR2, derived from virulence plasmid pSLT, is widespread in clinical isolates of Salmonella enterica serovar Typhimurium recovered in Spain and other European countries. pUO-StVR2 carries several genes encoding a FetMP-Fls system, which could be involved in iron uptake. We therefore analyzed S. Typhimurium LSP 146/02, a clinical strain selected as representative of the isolates carrying the plasmid, and an otherwise isogenic mutant lacking four genes (fetMP-flsDA) of the fetMP-fls region. Growth curves and determination of the intracellular iron content under iron-restricted conditions demonstrated that deletion of these genes impairs iron acquisition. Thus, under these conditions, the mutant grew significantly worse than the wild-type strain, its iron content was significantly lower, and it was outcompeted by the wild-type strain in competition assays. Importantly, the strain lacking the fetMP-flsDA genes was less invasive in cultured epithelial HeLa cells and replicated poorly upon infection of RAW264.7 macrophages. The genes were introduced into S. Typhimurium ATCC 14028, which lacks the FetMP-Fls system, and this resulted in increased growth under iron limitation as well as an increased ability to multiply inside macrophages. These findings indicate that the FetMP-Fls iron acquisition system exceeds the benefits conferred by the other high-affinity iron uptake systems carried by ATCC 14028 and LSP 146/02. We proposed that effective iron acquisition by this system in conjunction with antimicrobial resistance encoded from the same plasmid have greatly contributed to the epidemic success of S. Typhimurium isolates harboring pUO-StVR2.
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Affiliation(s)
- Vanesa García
- Department of Functional Biology, Section of Microbiology, University of Oviedo, 33006 Oviedo, Spain; (V.G.); (I.M.)
- Division of Microbiology, University of Osnabrück, 49076 Osnabrück, Germany; (A.F.-L.); (M.H.)
| | - Ana Herrero-Fresno
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (A.H.-F.); (J.E.O.)
| | - Rosaura Rodicio
- Department of Biochemistry and Molecular Biology, University of Oviedo, 33006 Oviedo, Spain;
- Translacional Microbiology Group, Health Research Institute of Principado de Asturias, 33011 Oviedo, Spain (ISPA)
| | - Alfonso Felipe-López
- Division of Microbiology, University of Osnabrück, 49076 Osnabrück, Germany; (A.F.-L.); (M.H.)
| | - Ignacio Montero
- Department of Functional Biology, Section of Microbiology, University of Oviedo, 33006 Oviedo, Spain; (V.G.); (I.M.)
| | - John E. Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (A.H.-F.); (J.E.O.)
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, 49076 Osnabrück, Germany; (A.F.-L.); (M.H.)
| | - María Rosario Rodicio
- Department of Functional Biology, Section of Microbiology, University of Oviedo, 33006 Oviedo, Spain; (V.G.); (I.M.)
- Translacional Microbiology Group, Health Research Institute of Principado de Asturias, 33011 Oviedo, Spain (ISPA)
- Correspondence: ; Tel.: +34-985103562
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25
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Williams CL, Neu HM, Alamneh YA, Reddinger RM, Jacobs AC, Singh S, Abu-Taleb R, Michel SLJ, Zurawski DV, Merrell DS. Characterization of Acinetobacter baumannii Copper Resistance Reveals a Role in Virulence. Front Microbiol 2020; 11:16. [PMID: 32117089 PMCID: PMC7015863 DOI: 10.3389/fmicb.2020.00016] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
Acinetobacter baumannii is often highly drug-resistant and causes severe infections in compromised patients. These infections can be life threatening due to limited treatment options. Copper is inherently antimicrobial and increasing evidence indicates that copper containing formulations may serve as non-traditional therapeutics against multidrug-resistant bacteria. We previously reported that A. baumannii is sensitive to high concentrations of copper. To understand A. baumannii copper resistance at the molecular level, herein we identified putative copper resistance components and characterized 21 strains bearing mutations in these genes. Eight of the strains displayed a copper sensitive phenotype (pcoA, pcoB, copB, copA/cueO, copR/cusR, copS/cusS, copC, copD); the putative functions of these proteins include copper transport, oxidation, sequestration, and regulation. Importantly, many of these mutant strains still showed increased sensitivity to copper while in a biofilm. Inductively coupled plasma mass spectrometry revealed that many of these strains had defects in copper mobilization, as the mutant strains accumulated more intracellular copper than the wild-type strain. Given the crucial antimicrobial role of copper-mediated killing employed by the immune system, virulence of these mutant strains was investigated in Galleria mellonella; many of the mutant strains were attenuated. Finally, the cusR and copD strains were also investigated in the murine pneumonia model; both were found to be important for full virulence. Thus, copper possesses antimicrobial activity against multidrug-resistant A. baumannii, and copper sensitivity is further increased when copper homeostasis mechanisms are interrupted. Importantly, these proteins are crucial for full virulence of A. baumannii and may represent novel drug targets.
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Affiliation(s)
- Caitlin L Williams
- Department of Microbiology & Immunology, Uniformed Services University, Bethesda, MD, United States
| | - Heather M Neu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Yonas A Alamneh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Ryan M Reddinger
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Anna C Jacobs
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Shweta Singh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Rania Abu-Taleb
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Sarah L J Michel
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Daniel V Zurawski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - D Scott Merrell
- Department of Microbiology & Immunology, Uniformed Services University, Bethesda, MD, United States
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26
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Thummeepak R, Pooalai R, Harrison C, Gannon L, Thanwisai A, Chantratita N, Millard AD, Sitthisak S. Essential Gene Clusters Involved in Copper Tolerance Identified in Acinetobacter baumannii Clinical and Environmental Isolates. Pathogens 2020; 9:pathogens9010060. [PMID: 31952222 PMCID: PMC7169445 DOI: 10.3390/pathogens9010060] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
Copper is widely used as antimicrobial in agriculture and medicine. Copper tolerance mechanisms of pathogenic bacteria have been proven to be required for both copper tolerance and survival during bacterial infections. Here, we determined both copper-tolerant phenotype and genotype in A. baumannii originated from clinical and environmental samples. Using copper susceptibility testing, copper-tolerant A. baumannii could be found in both clinical and environmental isolates. Genotypic study revealed that representative copper-related genes of the cluster A (cueR), B (pcoAB), and D (oprC) were detected in all isolates, while copRS of cluster C was detected in only copper-tolerant A. baumannii isolates. Moreover, we found that copper-tolerant phenotype was associated with amikacin resistance, while the presence of copRS was statistically associated with blaNDM-1. We chose the A. baumannii strain AB003 as a representative of copper-tolerant isolate to characterize the effect of copper treatment on external morphology as well as on genes responsible for copper tolerance. The morphological features and survival of A. baumannii AB003 were affected by its exposure to copper, while whole-genome sequencing and analysis showed that it carried fourteen copper-related genes located on four clusters, and cluster C of AB003 was found to be embedded on genomic island G08. Transcriptional analysis of fourteen copper-related genes identified in AB003 revealed that copper treatment induced the expressions of genes of clusters A, B, and D at the micromolar level, while genes of cluster C were over-expressed at the millimolar levels of copper. This study showed that both clinical and environmental A. baumannii isolates have the ability to tolerate copper and carried numerous copper tolerance determinants including intrinsic copper tolerance (clusters A, B, and D) and acquired copper tolerance (cluster C) that could respond to copper toxicity. Our evidence suggests that we need to reconsider the use of copper in hospitals and other medical environments to prevent the selection and spread of copper-tolerant organisms.
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Affiliation(s)
- Rapee Thummeepak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; (R.T.); (R.P.); (A.T.)
| | - Renuka Pooalai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; (R.T.); (R.P.); (A.T.)
| | - Christian Harrison
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK; (C.H.); (L.G.); (A.D.M.)
| | - Lucy Gannon
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK; (C.H.); (L.G.); (A.D.M.)
| | - Aunchalee Thanwisai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; (R.T.); (R.P.); (A.T.)
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand;
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Andrew D. Millard
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK; (C.H.); (L.G.); (A.D.M.)
| | - Sutthirat Sitthisak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; (R.T.); (R.P.); (A.T.)
- Correspondence: ; Tel.: +66-55-964626; Fax: +66-55-964770
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27
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Alquethamy SF, Adams FG, Naidu V, Khorvash M, Pederick VG, Zang M, Paton JC, Paulsen IT, Hassan KA, Cain AK, McDevitt CA, Eijkelkamp BA. The Role of Zinc Efflux during Acinetobacter baumannii Infection. ACS Infect Dis 2020; 6:150-158. [PMID: 31658418 DOI: 10.1021/acsinfecdis.9b00351] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Acinetobacter baumannii is a ubiquitous Gram-negative bacterium, that is associated with significant disease in immunocompromised individuals. The success of A. baumannii is partly attributable to its high level of antibiotic resistance. Further, A. baumannii expresses a broad arsenal of putative zinc efflux systems that are likely to aid environmental persistence and host colonization, but detailed insights into how the bacterium deals with toxic concentrations of zinc are lacking. In this study we present the transcriptomic responses of A. baumannii to toxic zinc concentrations. Subsequent mutant analyses revealed a primary role for the resistance-nodulation-cell division heavy metal efflux system CzcCBA, and the cation diffusion facilitator transporter CzcD in zinc resistance. To examine the role of zinc at the host-pathogen interface we utilized a murine model of zinc deficiency and challenge with wild-type and czcA mutant strains, which identified highly site-specific roles for zinc during A. baumannii infection. Overall, we provide novel insight into the key zinc resistance mechanisms of A. baumannii and outline the role these systems play in enabling the bacterium to survive in diverse environments.
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Affiliation(s)
- Saleh F. Alquethamy
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Elizabeth Street, Melbourne, Victoria 3000, Australia
| | - Felise G. Adams
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
- College of Science and Engineering, Flinders University, Sturt Road, Bedford Park, South Australia 5042, Australia
| | - Varsha Naidu
- Department of Molecular Sciences, Macquarie University, Balaclava Road, Macquarie Park, New South Wales 2109, Australia
| | - Marjan Khorvash
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Victoria G. Pederick
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Maoge Zang
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Ian T. Paulsen
- Department of Molecular Sciences, Macquarie University, Balaclava Road, Macquarie Park, New South Wales 2109, Australia
| | - Karl A. Hassan
- School of Environmental and Life Sciences, University of Newcastle, University Drive, Callaghan, New South Wales 2308, Australia
| | - Amy K. Cain
- Department of Molecular Sciences, Macquarie University, Balaclava Road, Macquarie Park, New South Wales 2109, Australia
| | - Christopher A. McDevitt
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Elizabeth Street, Melbourne, Victoria 3000, Australia
| | - Bart A. Eijkelkamp
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
- College of Science and Engineering, Flinders University, Sturt Road, Bedford Park, South Australia 5042, Australia
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28
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Lonergan ZR, Skaar EP. Nutrient Zinc at the Host-Pathogen Interface. Trends Biochem Sci 2019; 44:1041-1056. [PMID: 31326221 PMCID: PMC6864270 DOI: 10.1016/j.tibs.2019.06.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/13/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022]
Abstract
Zinc is an essential cofactor required for life and, as such, mechanisms exist for its homeostatic maintenance in biological systems. Despite the evolutionary distance between vertebrates and microbial life, there are parallel mechanisms to balance the essentiality of zinc with its inherent toxicity. Vertebrates regulate zinc homeostasis through a complex network of metal transporters and buffering systems that respond to changes in nutritional zinc availability or inflammation. Fine-tuning of this network becomes crucial during infections, where host nutritional immunity attempts to limit zinc availability to pathogens. However, accumulating evidence demonstrates that pathogens have evolved mechanisms to subvert host-mediated zinc withholding, and these metal homeostasis systems are important for survival within the host. We discuss here the mechanisms of vertebrate and bacterial zinc homeostasis and mobilization, as well as recent developments in our understanding of microbial zinc acquisition.
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Affiliation(s)
- Zachery R Lonergan
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Microbe-Host Interactions Training Program, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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29
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Xu Z, Wang P, Wang H, Yu ZH, Au-Yeung HY, Hirayama T, Sun H, Yan A. Zinc excess increases cellular demand for iron and decreases tolerance to copper in Escherichia coli. J Biol Chem 2019; 294:16978-16991. [PMID: 31586033 DOI: 10.1074/jbc.ra119.010023] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/25/2019] [Indexed: 12/11/2022] Open
Abstract
Transition metals serve as an important class of micronutrients that are indispensable for bacterial physiology but are cytotoxic when they are in excess. Bacteria have developed exquisite homeostatic systems to control the uptake, storage, and efflux of each of biological metals and maintain a thermodynamically balanced metal quota. However, whether the pathways that control the homeostasis of different biological metals cross-talk and render cross-resistance or sensitivity in the host-pathogen interface remains largely unknown. Here, we report that zinc (Zn) excess perturbs iron (Fe) and copper (Cu) homeostasis in Escherichia coli, resulting in increased Fe and decreased Cu levels in the cell. Gene expression analysis revealed that Zn excess transiently up-regulates Fe-uptake genes and down-regulates Fe-storage genes and thereby increases the cellular Fe quota. In vitro and in vivo protein-DNA binding assays revealed that the elevated intracellular Fe poisons the primary Cu detoxification transcription regulator CueR, resulting in dysregulation of its target genes copA and cueO and activation of the secondary Cu detoxification system CusSR-cusCFBA Supplementation with the Fe chelator 2,2'-dipyridyl (DIP) or with the reducing agent GSH abolished the induction of cusCFBA during Zn excess. Consistent with the importance of this metal homeostatic network in cell physiology, combined metal treatment, including simultaneously overloading cells with both Zn (0.25 mm) and Cu (0.25 mm) and sequestering Fe with DIP (50 μm), substantially inhibited E. coli growth. These results advance our understanding of bacterial metallobiology and may inform the development of metal-based antimicrobial regimens to manage infectious diseases.
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Affiliation(s)
- Zeling Xu
- School of Biological Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Pengchao Wang
- School of Biological Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Haibo Wang
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zuo Hang Yu
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ho Yu Au-Yeung
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Tasuku Hirayama
- Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, 1-25-4, Dairaku-nishi, Gifu, 501-1196, Japan
| | - Hongzhe Sun
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Aixin Yan
- School of Biological Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China
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30
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Ugwuja CG, Adelowo OO, Ogunlaja A, Omorogie MO, Olukanni OD, Ikhimiukor OO, Iermak I, Kolawole GA, Guenter C, Taubert A, Bodede O, Moodley R, Inada NM, de Camargo ASS, Unuabonah EI. Visible-Light-Mediated Photodynamic Water Disinfection @ Bimetallic-Doped Hybrid Clay Nanocomposites. ACS APPLIED MATERIALS & INTERFACES 2019; 11:25483-25494. [PMID: 31268651 DOI: 10.1021/acsami.9b01212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This study reports a new class of photocatalytic hybrid clay nanocomposites prepared from low-cost sources (kaolinite clay and Carica papaya seeds) doped with Zn and Cu salts via a solvothermal process. X-ray diffraction analysis suggests that Cu-doping and Cu/Zn-doping introduce new phases into the crystalline structure of Kaolinite clay, which is linked to the reduced band gap of kaolinite from typically between 4.9 and 8.2 eV to 2.69 eV for Cu-doped and 1.5 eV for Cu/Zn hybrid clay nanocomposites (Nisar, J.; Århammar, C.; Jämstorp, E.; Ahuja, R. Phys. Rev. B 2011, 84, 075120). In the presence of solar light irradiation, Cu- and Cu/Zn-doped nanocomposites facilitate the electron-hole pair separation. This promotes the generation of singlet oxygen which in turn improves the water disinfection efficiencies of these novel nanocomposite materials. The nanocomposite materials were further characterized using high-resolution scanning electron microscopy, fluorimetry, thermogravimetric analysis, and Raman spectroscopy. The breakthrough times of the nanocomposites for a fixed bed mode of disinfection of water contaminated with 2.32 × 107 cfu/mL E. coli ATCC 25922 under solar light irradiation are 25 h for Zn-doped, 30 h for Cu-doped, and 35 h for Cu/Zn-doped nanocomposites. In the presence of multidrug and multimetal resistant strains of E. coli, the breakthrough time decreases significantly. Zn-only doped nanocomposites are not photocatalytically active. In the absence of light, the nanocomposites are still effective in decontaminating water, although less efficient than under solar light irradiation. Electrostatic interaction, metal toxicity, and release of singlet oxygen (only in the Cu-doped and Cu/Zn-doped nanocomposites) are the three disinfection mechanisms by which these nanocomposites disinfect water. A regrowth study indicates the absence of any living E. coli cells in treated water even after 4 days. These data and the long hydraulic times (under gravity) exhibited by these nanocomposites during photodisinfection of water indicate an unusually high potential of these nanocomposites as efficient, affordable, and sustainable point-of-use systems for the disinfection of water in developing countries.
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Affiliation(s)
| | - Olawale O Adelowo
- Department of Microbiology , University of Ibadan , PMB 5116 , Ibadan , Oyo State 200284 , Nigeria
| | | | | | | | - Odion O Ikhimiukor
- Department of Microbiology , University of Ibadan , PMB 5116 , Ibadan , Oyo State 200284 , Nigeria
| | - Ievgeniia Iermak
- São Carlos Institute of Physics , University of São Paulo , Avenida Trabalhador Sãocarlense 400 , São Carlos 13566-590 , Brazil
| | - Gabriel A Kolawole
- Department of Chemistry , University of Zululand , Kwadlangezwa , 3886 , Republic of South Africa
| | | | | | - Olusola Bodede
- School of Chemistry and Physics , University of KwaZulu-Natal , Westville Campus , Durban , 3630 , South Africa
| | - Roshila Moodley
- School of Chemistry and Physics , University of KwaZulu-Natal , Westville Campus , Durban , 3630 , South Africa
| | - Natalia M Inada
- São Carlos Institute of Physics , University of São Paulo , Avenida Trabalhador Sãocarlense 400 , São Carlos 13566-590 , Brazil
| | - Andrea S S de Camargo
- São Carlos Institute of Physics , University of São Paulo , Avenida Trabalhador Sãocarlense 400 , São Carlos 13566-590 , Brazil
| | - Emmanuel I Unuabonah
- São Carlos Institute of Physics , University of São Paulo , Avenida Trabalhador Sãocarlense 400 , São Carlos 13566-590 , Brazil
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Wang J, Lonergan ZR, Gonzalez-Gutierrez G, Nairn BL, Maxwell CN, Zhang Y, Andreini C, Karty JA, Chazin WJ, Trinidad JC, Skaar EP, Giedroc DP. Multi-metal Restriction by Calprotectin Impacts De Novo Flavin Biosynthesis in Acinetobacter baumannii. Cell Chem Biol 2019; 26:745-755.e7. [PMID: 30905682 PMCID: PMC6525019 DOI: 10.1016/j.chembiol.2019.02.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/20/2019] [Accepted: 02/18/2019] [Indexed: 02/07/2023]
Abstract
Calprotectin (CP) inhibits bacterial viability through extracellular chelation of transition metals. However, how CP influences general metabolism remains largely unexplored. We show here that CP restricts bioavailable Zn and Fe to the pathogen Acinetobacter baumannii, inducing an extensive multi-metal perturbation of cellular physiology. Proteomics reveals severe metal starvation, and a strain lacking the candidate ZnII metallochaperone ZigA possesses altered cellular abundance of multiple essential Zn-dependent enzymes and enzymes in de novo flavin biosynthesis. The ΔzigA strain exhibits decreased cellular flavin levels during metal starvation. Flavin mononucleotide provides regulation of this biosynthesis pathway, via a 3,4-dihydroxy-2-butanone 4-phosphate synthase (RibB) fusion protein, RibBX, and authentic RibB. We propose that RibBX ensures flavin sufficiency under CP-induced Fe limitation, allowing flavodoxins to substitute for Fe-ferredoxins as cell reductants. These studies elucidate adaptation to nutritional immunity and define an intersection between metallostasis and cellular metabolism in A. baumannii.
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Affiliation(s)
- Jiefei Wang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Zachery R Lonergan
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Brittany L Nairn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christina N Maxwell
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Yixiang Zhang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Claudia Andreini
- Magnetic Resonance Centre (CERM), University of Florence, Florence, 50019 Sesto Fiorentino, Italy
| | - Jonathan A Karty
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Jonathan C Trinidad
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
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Abstract
A shift in the Western diet since the industrial revolution has resulted in a dramatic increase in the consumption of omega-6 fatty acids, with a concurrent decrease in the consumption of omega-3 fatty acids. This decrease in omega-3 fatty acid consumption has been associated with significant disease burden, including increased susceptibility to infectious diseases. Here we provide evidence that DHA, an omega-3 fatty acid, has superior antimicrobial effects upon the highly drug-resistant pathogen Acinetobacter baumannii, thereby providing insights into one of the potential health benefits of omega-3 fatty acids. The identification and characterization of two novel bacterial membrane protective mechanisms against host fatty acids provide important insights into A. baumannii adaptation during disease. Furthermore, we describe a novel role for the major multidrug efflux system AdeIJK in A. baumannii membrane maintenance and lipid transport. This core function, beyond drug efflux, increases the appeal of AdeIJK as a therapeutic target. Free fatty acids hold important immune-modulatory roles during infection. However, the host’s long-chain polyunsaturated fatty acids, not commonly found in the membranes of bacterial pathogens, also have significant broad-spectrum antibacterial potential. Of these, the omega-6 fatty acid arachidonic acid (AA) and the omega-3 fatty acid decosahexaenoic acid (DHA) are highly abundant; hence, we investigated their effects on the multidrug-resistant human pathogen Acinetobacter baumannii. Our analyses reveal that AA and DHA incorporate into the A. baumannii bacterial membrane and impact bacterial fitness and membrane integrity, with DHA having a more pronounced effect. Through transcriptional profiling and mutant analyses, we show that the A. baumannii β-oxidation pathway plays a protective role against AA and DHA, by limiting their incorporation into the phospholipids of the bacterial membrane. Furthermore, our study identified a second bacterial membrane protection system mediated by the AdeIJK efflux system, which modulates the lipid content of the membrane via direct efflux of lipids other than AA and DHA, thereby providing a novel function for this major efflux system in A. baumannii. This is the first study to examine the antimicrobial effects of host fatty acids on A. baumannii and highlights the potential of AA and DHA to protect against A. baumannii infections.
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Responses of Acidithiobacillus thiooxidans A01 to Individual and Joint Nickel (Ni2+) and Ferric (Fe3+). MINERALS 2019. [DOI: 10.3390/min9020082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Acidithiobacillus thiooxidans A01 is widely used in bioleaching processes and commonly thrives in most metal-rich environments. However, interactions between different heavy metals remain obscure. In this study, we elaborated the effect of ferric iron on the growth and gene expression of At. thiooxidans A01 under the stress of nickel. The results showed that 600 mM Ni2+ completely inhibited the growth and sulfur metabolism of At. thiooxidans A01. However, trace amounts of Fe3+ (0.5 mM) facilitated the growth of At. thiooxidans A01 in the presence of 600 mM Ni2+. With the addition of 5 mM Fe3+, the maximum cell density reached 1.84 × 108 cell/mL, and pH value was 0.95. In addition, metal resistance-related and sulfur metabolism genes were significantly up regulated with extra ferric iron. Taking the whole process into account, the promoting effect of Fe3+ addition can be attributed to the following: (1) alleviation of the effects of Ni2+ toxicity and restoring the growth of At. thiooxidans A01, (2) a choice of multiple pathways to export nickel ion and producing precursor of chelators of heavy metals. This can suggest that microorganisms may widely exhibit metabolic activity in iron-rich environments with heavy metals. Our study will facilitate the technique development for the processing of ore bodies with highly challenging ore compositions.
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The Role of the CopA Copper Efflux System in Acinetobacter baumannii Virulence. Int J Mol Sci 2019; 20:ijms20030575. [PMID: 30699983 PMCID: PMC6387184 DOI: 10.3390/ijms20030575] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 01/25/2019] [Accepted: 01/26/2019] [Indexed: 11/24/2022] Open
Abstract
Acinetobacter baumannii has emerged as one of the leading causative agents of nosocomial infections. Due to its high level of intrinsic and adapted antibiotic resistance, treatment failure rates are high, which allows this opportunistic pathogen to thrive during infection in immune-compromised patients. A. baumannii can cause infections within a broad range of host niches, with pneumonia and bacteraemia being associated with the greatest levels of morbidity and mortality. Although its resistance to antibiotics is widely studied, our understanding of the mechanisms required for dealing with environmental stresses related to virulence and hospital persistence, such as copper toxicity, is limited. Here, we performed an in silico analysis of the A. baumannii copper resistome, examining its regulation under copper stress. Using comparative analyses of bacterial P-type ATPases, we propose that A. baumannii encodes a member of a novel subgroup of P1B-1 ATPases. Analyses of three putative inner membrane copper efflux systems identified the P1B-1 ATPase CopA as the primary mediator of cytoplasmic copper resistance in A. baumannii. Using a murine model of A. baumannii pneumonia, we reveal that CopA contributes to the virulence of A. baumannii. Collectively, this study advances our understanding of how A. baumannii deals with environmental copper toxicity, and it provides novel insights into how A. baumannii combats adversities encountered as part of the host immune defence.
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Integrase-Controlled Excision of Metal-Resistance Genomic Islands in Acinetobacter baumannii. Genes (Basel) 2018; 9:genes9070366. [PMID: 30037042 PMCID: PMC6070778 DOI: 10.3390/genes9070366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/10/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
Genomic islands (GIs) are discrete gene clusters encoding for a variety of functions including antibiotic and heavy metal resistance, some of which are tightly associated to lineages of the core genome phylogenetic tree. We have investigated the functions of two distinct integrase genes in the mobilization of two metal resistant GIs, G08 and G62, of Acinetobacter baumannii. Real-time PCR demonstrated integrase-dependent GI excision, utilizing isopropyl β-d-1-thiogalactopyranoside IPTG-inducible integrase genes in plasmid-based mini-GIs in Escherichia coli. In A. baumannii, integrase-dependent excision of the original chromosomal GIs could be observed after mitomycin C induction. In both E. coli plasmids and A. baumannii chromosome, the rate of excision and circularization was found to be dependent on the expression level of the integrases. Susceptibility testing in A. baumannii strain ATCC 17978, A424, and their respective ΔG62 and ΔG08 mutants confirmed the contribution of the GI-encoded efflux transporters to heavy metal decreased susceptibility. In summary, the data evidenced the functionality of two integrases in the excision and circularization of the two Acinetobacter heavy-metal resistance GIs, G08 and G62, in E. coli, as well as when chromosomally located in their natural host. These recombination events occur at different frequencies resulting in genome plasticity and may participate in the spread of resistance determinants in A. baumannii.
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Abstract
Transition metals are required cofactors for many proteins that are critical for life, and their concentration within cells is carefully maintained to avoid both deficiency and toxicity. To defend against bacterial pathogens, vertebrate immune proteins sequester metals, in particular zinc, iron, and manganese, as a strategy to limit bacterial acquisition of these necessary nutrients in a process termed "nutritional immunity." In response, bacteria have evolved elegant strategies to access metals and counteract this host defense. In mammals, metal abundance can drastically shift due to changes in dietary intake or absorption from the intestinal tract, disrupting the balance between host and pathogen in the fight for metals and altering susceptibility to disease. This review describes the current understanding of how dietary metals modulate host-microbe interactions and the subsequent impact on the outcome of disease.
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Affiliation(s)
- Christopher A Lopez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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Eijkelkamp BA, Begg SL, Pederick VG, Trapetti C, Gregory MK, Whittall JJ, Paton JC, McDevitt CA. Arachidonic Acid Stress Impacts Pneumococcal Fatty Acid Homeostasis. Front Microbiol 2018; 9:813. [PMID: 29867785 PMCID: PMC5958418 DOI: 10.3389/fmicb.2018.00813] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Free fatty acids hold dual roles during infection, serving to modulate the host immune response while also functioning directly as antimicrobials. Of particular importance are the long chain polyunsaturated fatty acids, which are not commonly found in bacterial organisms, that have been proposed to have antibacterial roles. Arachidonic acid (AA) is a highly abundant long chain polyunsaturated fatty acid and we examined its effect upon Streptococcus pneumoniae. Here, we observed that in a murine model of S. pneumoniae infection the concentration of AA significantly increases in the blood. The impact of AA stress upon the pathogen was then assessed by a combination of biochemical, biophysical and microbiological assays. In vitro bacterial growth and intra-macrophage survival assays revealed that AA has detrimental effects on pneumococcal fitness. Subsequent analyses demonstrated that AA exerts antimicrobial activity via insertion into the pneumococcal membrane, although this did not increase the susceptibility of the bacterium to antibiotic, oxidative or metal ion stress. Transcriptomic profiling showed that AA treatment also resulted in a dramatic down-regulation of the genes involved in fatty acid biosynthesis, in addition to impacts on other metabolic processes, such as carbon-source utilization. Hence, these data reveal that AA has two distinct mechanisms of perturbing the pneumococcal membrane composition. Collectively, this work provides a molecular basis for the antimicrobial contribution of AA to combat pneumococcal infections.
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Affiliation(s)
- Bart A Eijkelkamp
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Stephanie L Begg
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Victoria G Pederick
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Claudia Trapetti
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Melissa K Gregory
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Jonathan J Whittall
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Christopher A McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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38
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Garber ME, Rajeev L, Kazakov AE, Trinh J, Masuno D, Thompson MG, Kaplan N, Luk J, Novichkov PS, Mukhopadhyay A. Multiple signaling systems target a core set of transition metal homeostasis genes using similar binding motifs. Mol Microbiol 2018; 107:704-717. [PMID: 29341298 DOI: 10.1111/mmi.13909] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/06/2018] [Accepted: 01/06/2018] [Indexed: 01/07/2023]
Abstract
Bacterial response to metals can require complex regulation. We report an overlapping regulation for copper and zinc resistance genes in the denitrifying bacterium, Pseudomonas stutzeri RCH2, by three two-component regulatory proteins CopR1, CopR2 and CzcR. We conducted genome-wide evaluations to identify gene targets of two paralogous regulators, CopR1 and CopR2, annotated for copper signaling, and compared the results with the gene targets for CzcR, implicated in zinc signaling. We discovered that the CopRs and CzcR have largely common targets, and crossregulate a core set of P. stutzeri copper and zinc responsive genes. We established that this crossregulation is enabled by a conserved binding motif in the upstream regulatory regions of the target genes. The crossregulation is physiologically relevant as these regulators synergistically and antagonistically target multicopper oxidases, metal efflux and sequestration systems. CopR1 and CopR2 upregulate two cop operons encoding copper tolerance genes, while all three regulators downregulate a putative copper chaperone, Psest_1595. CzcR also upregulated the oprD gene and the CzcIABC Zn2+ efflux system, while CopR1 and CopR2 downregulated these genes. Our study suggests that crossregulation of copper and zinc homeostasis can be advantageous, and in P. stutzeri this is enabled by shared binding motifs for multiple response regulators.
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Affiliation(s)
- Megan E Garber
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Comparative Biochemistry, University of California, Berkeley, CA, 94720, USA
| | - Lara Rajeev
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jessica Trinh
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Duy Masuno
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mitchell G Thompson
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Nurgul Kaplan
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Joyce Luk
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Pavel S Novichkov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Energy, Knowledge Base, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aindrila Mukhopadhyay
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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