1
|
Akbari MS, Keogh RA, Radin JN, Sanchez-Rosario Y, Johnson MDL, Horswill AR, Kehl-Fie TE, Burcham LR, Doran KS. The impact of nutritional immunity on Group B streptococcal pathogenesis during wound infection. mBio 2023; 14:e0030423. [PMID: 37358277 PMCID: PMC10470527 DOI: 10.1128/mbio.00304-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/09/2023] [Indexed: 06/27/2023] Open
Abstract
Group B Streptococcus (GBS) is a Gram-positive pathobiont that can cause adverse health outcomes in neonates and vulnerable adult populations. GBS is one of the most frequently isolated bacteria from diabetic (Db) wound infections but is rarely found in the non-diabetic (nDb) wound environment. Previously, RNA sequencing of wound tissue from Db wound infections in leprdb diabetic mice showed increased expression of neutrophil factors, and genes involved in GBS metal transport such as the zinc (Zn), manganese (Mn), and putative nickel (Ni) import systems. Here, we develop a Streptozotocin-induced diabetic wound model to evaluate the pathogenesis of two invasive strains of GBS, serotypes Ia and V. We observe an increase in metal chelators such as calprotectin (CP) and lipocalin-2 during diabetic wound infections compared to nDb. We find that CP limits GBS survival in wounds of non-diabetic mice but does not impact survival in diabetic wounds. Additionally, we utilize GBS metal transporter mutants and determine that the Zn, Mn, and putative Ni transporters in GBS are dispensable in diabetic wound infection but contributed to bacterial persistence in non-diabetic animals. Collectively, these data suggest that in non-diabetic mice, functional nutritional immunity mediated by CP is effective at mitigating GBS infection, whereas in diabetic mice, the presence of CP is not sufficient to control GBS wound persistence. IMPORTANCE Diabetic wound infections are difficult to treat and often become chronic due to an impaired immune response as well as the presence of bacterial species that establish persistent infections. Group B Streptococcus (GBS) is one of the most frequently isolated bacterial species in diabetic wound infections and, as a result, is one of the leading causes of death from skin and subcutaneous infection. However, GBS is notoriously absent in non-diabetic wounds, and little is known about why this species thrives in diabetic infection. The work herein investigates how alterations in diabetic host immunity may contribute to GBS success during diabetic wound infection.
Collapse
Affiliation(s)
- Madeline S. Akbari
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Rebecca A. Keogh
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jana N. Radin
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Yamil Sanchez-Rosario
- Department of Immunobiology, University of Arizona College of Medicine—Tucson, Tucson, Arizona, USA
| | - Michael D. L. Johnson
- Department of Immunobiology, University of Arizona College of Medicine—Tucson, Tucson, Arizona, USA
- Valley Fever Center for Excellence, University of Arizona College of Medicine—Tucson, Tucson, Arizona, USA
- BIO5 Institute, University of Arizona College of Medicine—Tucson, Tucson, Arizona, USA
- Asthma and Airway Disease Research Center, University of Arizona College of Medicine—Tucson, Tucson, Arizona, USA
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Veterans Affairs, VA Eastern Colorado Health Care System, Aurora, Colorado, USA
| | - Thomas E. Kehl-Fie
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Lindsey R. Burcham
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| |
Collapse
|
2
|
Stephens AC, Richardson AR. Recent developments in our understanding of the physiology and nitric oxide-resistance of Staphylococcus aureus. Adv Microb Physiol 2022; 81:111-135. [PMID: 36167441 DOI: 10.1016/bs.ampbs.2022.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Staphylococcus aureus is an important human pathogen causing a wide range of disease presentations. It harbors a vast array of virulence factors and drug-resistance determinants. All of these factors are coordinately regulated by a hand full of key transcriptional regulators. The regulation and expression of these factors are tightly intertwined with the metabolic state of the cell. Furthermore, alterations in central metabolism are also key to the ability of S. aureus to resist clearance by the host innate immune response, including nitric oxide (NO·) production. Given the fact that central metabolism directly influences virulence, drug resistance and immune tolerance in S. aureus, a better understanding of the metabolic capabilities of this pathogen is critical. This work highlights some of the major findings within the last five years surrounding S. aureus central metabolism, both organic and inorganic. These are also put in the context of the unique NO·-resistance associated with this pathogen as well as their contributions to virulence. The more we understand the intersection between central metabolism and virulence capabilities in S. aureus, the better the chances of developing novel therapeutics so desperately needed to treat this pathogen.
Collapse
Affiliation(s)
- Amelia C Stephens
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, United States
| | - Anthony R Richardson
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, United States.
| |
Collapse
|
3
|
In vivo growth of Staphylococcus lugdunensis is facilitated by the concerted function of heme and non-heme iron acquisition mechanisms. J Biol Chem 2022; 298:101823. [PMID: 35283192 PMCID: PMC9052147 DOI: 10.1016/j.jbc.2022.101823] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus lugdunensis has increasingly been recognized as a pathogen that can cause serious infection indicating this bacterium overcomes host nutritional immunity. Despite this, there exists a significant knowledge gap regarding the iron acquisition mechanisms employed by S. lugdunensis, especially during infection of the mammalian host. Here we show that S. lugdunensis can usurp hydroxamate siderophores and staphyloferrin A and B from Staphylococcus aureus. These transport activities all required a functional FhuC ATPase. Moreover, we show that the acquisition of catechol siderophores and catecholamine stress hormones by S. lugdunensis required the presence of the sst-1 transporter-encoding locus, but not the sst-2 locus. Iron-dependent growth in acidic culture conditions necessitated the ferrous iron transport system encoded by feoAB. Heme iron was acquired via expression of the iron-regulated surface determinant (isd) locus. During systemic infection of mice, we demonstrated that while S. lugdunensis does not cause overt illness, it does colonize and proliferate to high numbers in the kidneys. By combining mutations in the various iron acquisition loci (isd, fhuC, sst-1, and feo), we demonstrate that only a strain deficient for all of these systems was attenuated in its ability to proliferate to high numbers in the murine kidney. We propose the concerted action of heme and non-heme iron acquisition systems also enable S. lugdunensis to cause human infection.
Collapse
|
4
|
Staphylococcus aureus Preferentially Liberates Inorganic Phosphate from Organophosphates in Environments where This Nutrient Is Limiting. J Bacteriol 2020; 202:JB.00264-20. [PMID: 32868400 DOI: 10.1128/jb.00264-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/27/2020] [Indexed: 11/20/2022] Open
Abstract
Phosphate is an essential nutrient that Staphylococcus aureus and other pathogens must acquire from the host during infection. While inorganic monophosphate (Pi) is the preferred source of this nutrient, bacteria can also obtain it from phosphate-containing organic molecules. The Pi-responsive regulator PhoPR is necessary for S. aureus to cause infection, suggesting that Pi is not freely available during infection and that this nutrient must be obtained from other sources. However, the organophosphates from which S. aureus can obtain phosphate are unknown. We evaluated the ability of 58 phosphorus-containing molecules to serve as phosphate sources for S. aureus Forty-six of these compounds, including phosphorylated amino acids, sugars, and nucleotides, supported growth. Among the organophosphate sources was glycerol-3-phosphate (G3P), which is commonly found in the mammalian host. Differing from the model organism Escherichia coli, S. aureus does not import G3P intact to obtain Pi Instead, S. aureus relies on the phosphatase PhoB to release Pi from G3P, which is subsequently imported by Pi transporters. To determine if this strategy is used by S. aureus to extract phosphate from other phosphate sources, we assessed the ability of PhoB- and Pi transporter-deficient strains to grow on the same library of phosphorus-containing molecules. Sixty percent of the substrates (28/46) relied on the PhoB/Pi transporter pathway, and an additional 10/46 (22%) were PhoB independent but still required Pi transport through the Pi transporters. Cumulatively, these results suggest that in Pi-limited environments, S. aureus preferentially generates Pi from organophosphates and then relies on Pi transporters to import this nutrient.IMPORTANCE For bacteria, the preferred form of the essential nutrient phosphate is inorganic monophosphate (Pi), but phosphate can also be extracted from a variety of phosphocompounds. Pathogens, including Staphylococcus aureus, experience Pi limitation within the host, suggesting that the use of alternative phosphate sources is important during infection. However, the alternative phosphate sources that can be used by S. aureus and others remain largely unexplored. We screened a library of phosphorus-containing compounds for the ability to support growth as a phosphate source. S. aureus could use a variety of phosphocompounds, including nucleotides, phosphosugars, and phosphoamino acids. Subsequent genetic analysis determined that a majority of these alternative phosphate sources are first processed extracellularly to liberate Pi, which is then imported through Pi transporters.
Collapse
|