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Zelmer AR, Yang D, Gunn NJ, Solomon LB, Nelson R, Kidd SP, Richter K, Atkins GJ. Osteomyelitis-relevant antibiotics at clinical concentrations show limited effectivity against acute and chronic intracellular S. aureus infections in osteocytes. Antimicrob Agents Chemother 2024:e0080824. [PMID: 39194210 DOI: 10.1128/aac.00808-24] [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: 06/02/2024] [Accepted: 08/09/2024] [Indexed: 08/29/2024] Open
Abstract
Osteomyelitis caused by Staphylococcus aureus can involve the persistent infection of osteocytes. We sought to determine if current clinically utilized antibiotics were capable of clearing an intracellular osteocyte S. aureus infection. Rifampicin, vancomycin, levofloxacin, ofloxacin, amoxicillin, oxacillin, doxycycline, linezolid, gentamicin, and tigecycline were assessed for their minimum inhibitory concentration (MIC) and minimum bactericidal concentrations against 12 S. aureus strains, at pH 5.0 and 7.2 to mimic lysosomal and cytoplasmic environments, respectively. Those antibiotics whose bone estimated achievable concentration was commonly above their respective MIC for the strains tested were further assayed in a human osteocyte infection model under acute and chronic conditions. Osteocyte-like cells were treated at 1×, 4×, and 10× the MIC for 1 and 7 days following infection (acute model), or at 15 and 21 days of infection (chronic model). The intracellular effectivity of each antibiotic was measured in terms of CFU reduction, small colony variant formation, and bacterial mRNA expression change. Only rifampicin, levofloxacin, and linezolid reduced intracellular CFU numbers significantly in the acute model. Consistent with the transition to a non-culturable state, few if any CFU could be recovered from the chronic model. However, no treatment in either model reduced the quantity of bacterial mRNA or prevented non-culturable bacteria from returning to a culturable state. These findings indicate that S. aureus adapts phenotypically during intracellular infection of osteocytes, adopting a reversible quiescent state that is protected against antibiotics, even at 10× their MIC. Thus, new therapeutic approaches are necessary to cure S. aureus intracellular infections in osteomyelitis.
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Affiliation(s)
- Anja R Zelmer
- Center for Orthopedic and Trauma Research, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Dongqing Yang
- Center for Orthopedic and Trauma Research, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Nicholas J Gunn
- Center for Orthopedic and Trauma Research, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
| | - L Bogdan Solomon
- Center for Orthopedic and Trauma Research, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
- Department of Orthopedics and Trauma, Royal Adelaide Hospital, Adelaide, Australia
| | - Renjy Nelson
- Department of Infectious Diseases, Central Adelaide Local Health Network, Adelaide, Australia
| | - Stephen P Kidd
- Australian Center for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
- Research Center for Infectious Disease, School of Biological Science, University of Adelaide, Adelaide, Australia
| | - Katharina Richter
- Department of Surgery, Richter Lab, Basil Hetzel Institute for Translational Health Research, University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, Australia
| | - Gerald J Atkins
- Center for Orthopedic and Trauma Research, Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
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2
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Nguyen A, Roy JJS, Kim JH, Yun KH, Lee W, Kim KK, Kim T, Chaurasia AK. Repeated Exposure of Vancomycin to Vancomycin-Susceptible Staphylococcus aureus (VSSA) Parent Emerged VISA and VRSA Strains with Enhanced Virulence Potentials. J Microbiol 2024; 62:535-553. [PMID: 38814539 DOI: 10.1007/s12275-024-00139-8] [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: 11/25/2023] [Revised: 04/18/2024] [Accepted: 04/21/2024] [Indexed: 05/31/2024]
Abstract
The emergence of resistance against the last-resort antibiotic vancomycin in staphylococcal infections is a serious concern for human health. Although various drug-resistant pathogens of diverse genetic backgrounds show higher virulence potential, the underlying mechanism behind this is not yet clear due to variability in their genetic dispositions. In this study, we investigated the correlation between resistance and virulence in adaptively evolved isogenic strains. The vancomycin-susceptible Staphylococcus aureus USA300 was exposed to various concentrations of vancomycin repeatedly as a mimic of the clinical regimen to obtain mutation(s)-accrued-clonally-selected (MACS) strains. The phenotypic analyses followed by expression of the representative genes responsible for virulence and resistance of MACS strains were investigated. MACS strains obtained under 2 and 8 µg/ml vancomycin, named Van2 and Van8, respectively; showed enhanced vancomycin minimal inhibitory concentrations (MIC) to 4 and 16 µg/ml, respectively. The cell adhesion and invasion of MACS strains increased in proportion to their MICs. The correlation between resistance and virulence potential was partially explained by the differential expression of genes known to be involved in both virulence and resistance in MACS strains compared to parent S. aureus USA300. Repeated treatment of vancomycin against vancomycin-susceptible S. aureus (VSSA) leads to the emergence of vancomycin-resistant strains with variable levels of enhanced virulence potentials.
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Affiliation(s)
- An Nguyen
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
- Department of Biophysics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - J Jean Sophy Roy
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Ji-Hoon Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Kyung-Hee Yun
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Wonsik Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
- Department of Biophysics, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Truc Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
| | - Akhilesh Kumar Chaurasia
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
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3
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Mahieu L, Van Moll L, De Vooght L, Delputte P, Cos P. In vitro modelling of bacterial pneumonia: a comparative analysis of widely applied complex cell culture models. FEMS Microbiol Rev 2024; 48:fuae007. [PMID: 38409952 PMCID: PMC10913945 DOI: 10.1093/femsre/fuae007] [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: 10/02/2023] [Revised: 01/29/2024] [Accepted: 02/24/2024] [Indexed: 02/28/2024] Open
Abstract
Bacterial pneumonia greatly contributes to the disease burden and mortality of lower respiratory tract infections among all age groups and risk profiles. Therefore, laboratory modelling of bacterial pneumonia remains important for elucidating the complex host-pathogen interactions and to determine drug efficacy and toxicity. In vitro cell culture enables for the creation of high-throughput, specific disease models in a tightly controlled environment. Advanced human cell culture models specifically, can bridge the research gap between the classical two-dimensional cell models and animal models. This review provides an overview of the current status of the development of complex cellular in vitro models to study bacterial pneumonia infections, with a focus on air-liquid interface models, spheroid, organoid, and lung-on-a-chip models. For the wide scale, comparative literature search, we selected six clinically highly relevant bacteria (Pseudomonas aeruginosa, Mycoplasma pneumoniae, Haemophilus influenzae, Mycobacterium tuberculosis, Streptococcus pneumoniae, and Staphylococcus aureus). We reviewed the cell lines that are commonly used, as well as trends and discrepancies in the methodology, ranging from cell infection parameters to assay read-outs. We also highlighted the importance of model validation and data transparency in guiding the research field towards more complex infection models.
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Affiliation(s)
- Laure Mahieu
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Laurence Van Moll
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Linda De Vooght
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Peter Delputte
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Paul Cos
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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4
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Subramaniam S, Joyce P, Ogunniyi AD, Dube A, Sampson SL, Lehr CM, Prestidge CA. Minimum Information for Conducting and Reporting In Vitro Intracellular Infection Assays. ACS Infect Dis 2024; 10:337-349. [PMID: 38295053 DOI: 10.1021/acsinfecdis.3c00613] [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] [Indexed: 02/02/2024]
Abstract
Bacterial pathogens are constantly evolving to outsmart the host immune system and antibiotics developed to eradicate them. One key strategy involves the ability of bacteria to survive and replicate within host cells, thereby causing intracellular infections. To address this unmet clinical need, researchers are adopting new approaches, such as the development of novel molecules that can penetrate host cells, thus exerting their antimicrobial activity intracellularly, or repurposing existing antibiotics using nanocarriers (i.e., nanoantibiotics) for site-specific delivery. However, inconsistency in information reported across published studies makes it challenging for scientific comparison and judgment of experiments for future direction by researchers. Together with the lack of reproducibility of experiments, these inconsistencies limit the translation of experimental results beyond pre-clinical evaluation. Minimum information guidelines have been instrumental in addressing such challenges in other fields of biomedical research. Guidelines and recommendations provided herein have been designed for researchers as essential parameters to be disclosed when publishing their methodology and results, divided into four main categories: (i) experimental design, (ii) establishing an in vitro model, (iii) assessment of efficacy of novel therapeutics, and (iv) statistical assessment. These guidelines have been designed with the intention to improve the reproducibility and rigor of future studies while enabling quantitative comparisons of published studies, ultimately facilitating translation of emerging antimicrobial technologies into clinically viable therapies that safely and effectively treat intracellular infections.
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Affiliation(s)
- Santhni Subramaniam
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Paul Joyce
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Abiodun D Ogunniyi
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Admire Dube
- School of Pharmacy, University of the Western Cape, Bellville, 7535 Cape Town, South Africa
| | - Samantha L Sampson
- South African Medical Research Council Centre for Tuberculosis Research, and Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, 7602 Cape Town, South Africa
| | - Claus-Michael Lehr
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, 66123 Saarbrücken, Germany
- Department of Pharmacy, Saarland University, Campus Building E8.1, 66123 Saarbrücken, Germany
| | - Clive A Prestidge
- UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
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Lo HY, Long DR, Holmes EA, Penewit K, Hodgson T, Lewis JD, Waalkes A, Salipante SJ. Transposon sequencing identifies genes impacting Staphylococcus aureus invasion in a human macrophage model. Infect Immun 2023; 91:e0022823. [PMID: 37676013 PMCID: PMC10580828 DOI: 10.1128/iai.00228-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 09/08/2023] Open
Abstract
Staphylococcus aureus is a facultative intracellular pathogen in many host cell types, facilitating its persistence in chronic infections. The genes contributing to intracellular pathogenesis have not yet been fully enumerated. Here, we cataloged genes influencing S. aureus invasion and survival within human THP-1 derived macrophages using two laboratory strains (ATCC2913 and JE2). We developed an in vitro transposition method to produce highly saturated transposon mutant libraries in S. aureus and performed transposon insertion sequencing (Tn-Seq) to identify candidate genes with significantly altered abundance following macrophage invasion. While some significant genes were strain-specific, 108 were identified as common across both S. aureus strains, with most (n = 106) being required for optimal macrophage infection. We used CRISPR interference (CRISPRi) to functionally validate phenotypic contributions for a subset of genes. Of the 20 genes passing validation, seven had previously identified roles in S. aureus virulence, and 13 were newly implicated. Validated genes frequently evidenced strain-specific effects, yielding opposing phenotypes when knocked down in the alternative strain. Genomic analysis of de novo mutations occurring in groups (n = 237) of clonally related S. aureus isolates from the airways of chronically infected individuals with cystic fibrosis (CF) revealed significantly greater in vivo purifying selection in conditionally essential candidate genes than those not associated with macrophage invasion. This study implicates a core set of genes necessary to support macrophage invasion by S. aureus, highlights strain-specific differences in phenotypic effects of effector genes, and provides evidence for selection of candidate genes identified by Tn-Seq analyses during chronic airway infection in CF patients in vivo.
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Affiliation(s)
- Hsin-Yu Lo
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Dustin R. Long
- Division of Critical Care Medicine, Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Elizbeth A. Holmes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Kelsi Penewit
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Taylor Hodgson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Janessa D. Lewis
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam Waalkes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Stephen J. Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
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6
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Sultan M, Arya R, Chaurasia AK, Kim KK. Sensor histidine kinases kdpD and aauS regulate biofilm and virulence in Pseudomonas aeruginosa PA14. Front Cell Infect Microbiol 2023; 13:1270667. [PMID: 37881370 PMCID: PMC10595159 DOI: 10.3389/fcimb.2023.1270667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023] Open
Abstract
Pseudomonas aeruginosa is a multidrug-resistant opportunistic human pathogen that utilizes two-component systems (TCSs) to sense pathophysiological signals and coordinate virulence. P. aeruginosa contains 64 sensor histidine kinases (HKs) and 72 response regulators (RRs) that play important roles in metabolism, bacterial physiology, and virulence. However, the role of some TCSs in virulence remains uncharacterized. In this study, we evaluated the virulence potential of some uncharacterized sensor HK and RR knockouts in P. aeruginosa using a Galleria mellonella infection model. Furthermore, we demonstrated that KdpD and AauS HKs regulate virulence by affecting P. aeruginosa biofilm formation and motility. Both ΔkdpD and ΔaauS showed reduced biofilm and motility which were confirmed by restored phenotypes upon complementation. Moreover, ΔkdpD and ΔaauS exhibited increased survival of HeLa cells and G. mellonella during in vivo infection. Altered expression of the transcriptional regulators anR and lasR, along with the virulence genes lasA, pelA, cupA, pqsA, pqsB, pqsC, and pqsD in the mutant strains elucidated the mechanism by which ΔkdpD and ΔaauS affect virulence. These findings confirm that kdpD and aauS play important roles in P. aeruginosa pathogenesis by regulating biofilm formation and motility.
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Affiliation(s)
- Maria Sultan
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Rekha Arya
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
- Department of Orthopedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Akhilesh Kumar Chaurasia
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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7
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Hachani A, Giulieri SG, Guérillot R, Walsh CJ, Herisse M, Soe YM, Baines SL, Thomas DR, Cheung SD, Hayes AS, Cho E, Newton HJ, Pidot S, Massey RC, Howden BP, Stinear TP. A high-throughput cytotoxicity screening platform reveals agr-independent mutations in bacteraemia-associated Staphylococcus aureus that promote intracellular persistence. eLife 2023; 12:e84778. [PMID: 37289634 PMCID: PMC10259494 DOI: 10.7554/elife.84778] [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: 11/08/2022] [Accepted: 05/23/2023] [Indexed: 06/10/2023] Open
Abstract
Staphylococcus aureus infections are associated with high mortality rates. Often considered an extracellular pathogen, S. aureus can persist and replicate within host cells, evading immune responses, and causing host cell death. Classical methods for assessing S. aureus cytotoxicity are limited by testing culture supernatants and endpoint measurements that do not capture the phenotypic diversity of intracellular bacteria. Using a well-established epithelial cell line model, we have developed a platform called InToxSa (intracellular toxicity of S. aureus) to quantify intracellular cytotoxic S. aureus phenotypes. Studying a panel of 387 S. aureus bacteraemia isolates, and combined with comparative, statistical, and functional genomics, our platform identified mutations in S. aureus clinical isolates that reduced bacterial cytotoxicity and promoted intracellular persistence. In addition to numerous convergent mutations in the Agr quorum sensing system, our approach detected mutations in other loci that also impacted cytotoxicity and intracellular persistence. We discovered that clinical mutations in ausA, encoding the aureusimine non-ribosomal peptide synthetase, reduced S. aureus cytotoxicity, and increased intracellular persistence. InToxSa is a versatile, high-throughput cell-based phenomics platform and we showcase its utility by identifying clinically relevant S. aureus pathoadaptive mutations that promote intracellular residency.
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Affiliation(s)
- Abderrahman Hachani
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Stefano G Giulieri
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Romain Guérillot
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Calum J Walsh
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Marion Herisse
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Ye Mon Soe
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Sarah L Baines
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - David R Thomas
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
- Infection and Immunity Program, Department of Microbiology and Biomedicine Discovery Institute, Monash UniversityClaytonAustralia
| | - Shane Doris Cheung
- Biological Optical Microscopy Platform, University of MelbourneMelbourneAustralia
| | - Ashleigh S Hayes
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Ellie Cho
- Biological Optical Microscopy Platform, University of MelbourneMelbourneAustralia
| | - Hayley J Newton
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
- Infection and Immunity Program, Department of Microbiology and Biomedicine Discovery Institute, Monash UniversityClaytonAustralia
| | - Sacha Pidot
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Ruth C Massey
- School of Microbiology, University College CorkCorkIreland
- School of Medicine, University College CorkCorkIreland
- APC Microbiome Ireland, University College CorkCorkIreland
- School of Cellular and Molecular Medicine, University of BristolBristolUnited Kingdom
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Doherty Institute, University of MelbourneMelbourneAustralia
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8
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Rigaill J, Gavid M, Fayolle M, Morgene MF, Lelonge Y, Grattard F, Pozzetto B, Crépin A, Prades JM, Laurent F, Botelho-Nevers E, Berthelot P, Verhoeven PO. Staphylococcus aureus nasal colonization level and intracellular reservoir: a prospective cohort study. Eur J Clin Microbiol Infect Dis 2023; 42:621-629. [PMID: 36964269 DOI: 10.1007/s10096-023-04591-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 03/15/2023] [Indexed: 03/26/2023]
Abstract
Staphylococcus aureus is a major pathogen in humans. The nasal vestibule is considered as the main reservoir of S. aureus. However, even though the nasal cavity may also be colonized by S. aureus, the relationships between the two sites are still unclear. We conducted a prospective study in humans to assess the S. aureus colonization profiles in the vestibule and nasal cavity, and to investigate the presence of intracellular S. aureus in the two sites. Patients undergoing ear, nose, and throat surgery were swabbed during endoscopy to determine S. aureus nasal load, genotype, and presence of intracellular S. aureus. Among per-operative samples from 90 patients, the prevalence of S. aureus carriage was 32.2% and 33.3% in the vestibule and the nasal cavity, respectively. The mean S. aureus load was 4.10 and 4.25 log10 CFU/swab for the nasal vestibule and nasal cavity, respectively (P > 0.05). Genotyping of S. aureus revealed that all nasal strains isolated from a given individual belong to the same clonal complex and spa-type. An intracellular carriage was observed in 5.6% of the patients, all of whom exhibited a S. aureus vestibule load higher than 3 log10 CFU/swab. An intracellular niche was observed in the vestibule as well as in the nasal cavity. In conclusion, the nasal cavity was also found to be a major site of S. aureus carriage in humans and should draw attention when studying host-pathogen interactions related to the risk of infection associated with colonization.
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Affiliation(s)
- Josselin Rigaill
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Agents and Hygiene, University Hospital of St-Etienne, St-Etienne, France
| | - Marie Gavid
- Department of Ear Nose Throat Surgery, University Hospital of St-Etienne, St-Etienne, France
| | - Martin Fayolle
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Agents and Hygiene, University Hospital of St-Etienne, St-Etienne, France
| | - Mohamed Fedy Morgene
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
| | - Yann Lelonge
- Department of Ear Nose Throat Surgery, University Hospital of St-Etienne, St-Etienne, France
| | - Florence Grattard
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Agents and Hygiene, University Hospital of St-Etienne, St-Etienne, France
| | - Bruno Pozzetto
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Agents and Hygiene, University Hospital of St-Etienne, St-Etienne, France
| | - Adeline Crépin
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
| | - Jean-Michel Prades
- Department of Ear Nose Throat Surgery, University Hospital of St-Etienne, St-Etienne, France
| | - Frédéric Laurent
- CIRI - Centre International de Recherche en Infectiologie, Staphylococcal Pathogenesis team, Université de Lyon, Inserm, U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Department of Bacteriology, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Elisabeth Botelho-Nevers
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Diseases, University Hospital of St-Etienne, St-Etienne, France
| | - Philippe Berthelot
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Faculty of Medicine, University Jean Monnet, St-Etienne, France
- Department of Infectious Diseases, University Hospital of St-Etienne, St-Etienne, France
| | - Paul O Verhoeven
- CIRI - Centre International de Recherche en Infectiologie, GIMAP team, Université de Lyon, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France.
- Faculty of Medicine, University Jean Monnet, St-Etienne, France.
- Department of Infectious Agents and Hygiene, University Hospital of St-Etienne, St-Etienne, France.
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9
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Hinman KD, Laforce-Nesbitt SS, Cohen JT, Mundy M, Bliss JM, Horswill AR, Lefort CT. Bi-fluorescent Staphylococcus aureus infection enables single-cell analysis of intracellular killing in vivo. Front Immunol 2023; 14:1089111. [PMID: 36756129 PMCID: PMC9900177 DOI: 10.3389/fimmu.2023.1089111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/03/2023] [Indexed: 01/24/2023] Open
Abstract
Techniques for studying the clearance of bacterial infections are critical for advances in understanding disease states, immune cell effector functions, and novel antimicrobial therapeutics. Intracellular killing of Staphylococcus aureus by neutrophils can be monitored using a S. aureus strain stably expressing GFP, a fluorophore that is quenched when exposed to the reactive oxygen species (ROS) present in the phagolysosome. Here, we expand upon this method by developing a bi-fluorescent S. aureus killing assay for use in vivo. Conjugating S. aureus with a stable secondary fluorescent marker enables the separation of infected cell samples into three populations: cells that have not engaged in phagocytosis, cells that have engulfed and killed S. aureus, and cells that have viable internalized S. aureus. We identified ATTO647N-NHS Ester as a favorable dye conjugate for generating bi-fluorescent S. aureus due to its stability over time and invariant signal within the neutrophil phagolysosome. To resolve the in vivo utility of ATTO647N/GFP bi-fluorescent S. aureus, we evaluated neutrophil function in a murine model of chronic granulomatous disease (CGD) known to have impaired clearance of S. aureus infection. Analysis of bronchoalveolar lavage (BAL) from animals subjected to pulmonary infection with bi-fluorescent S. aureus demonstrated differences in neutrophil antimicrobial function consistent with the established phenotype of CGD.
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Affiliation(s)
- Kristina D Hinman
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States.,Warren Alpert Medical School, Brown University, Providence, RI, United States.,Graduate Program in Pathobiology, Brown University, Providence, RI, United States
| | | | - Joshua T Cohen
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States
| | - Miles Mundy
- Graduate Program in Pathobiology, Brown University, Providence, RI, United States
| | - Joseph M Bliss
- Warren Alpert Medical School, Brown University, Providence, RI, United States.,Department of Pediatrics, Women and Infants Hospital, Providence, RI, United States
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Craig T Lefort
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States.,Warren Alpert Medical School, Brown University, Providence, RI, United States
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10
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Role of Staphylococcus aureus Formate Metabolism during Prosthetic Joint Infection. Infect Immun 2022; 90:e0042822. [PMID: 36286525 PMCID: PMC9670962 DOI: 10.1128/iai.00428-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms are bacterial communities characterized by antibiotic tolerance.
Staphylococcus aureus
is a leading cause of biofilm infections on medical devices, including prosthetic joints, which represent a significant health care burden. The major leukocyte infiltrate associated with
S. aureus
prosthetic joint infection (PJI) is granulocytic myeloid-derived suppressor cells (G-MDSCs), which produce IL-10 to promote biofilm persistence by inhibiting monocyte and macrophage proinflammatory activity.
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11
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Zha J, Li J, Su Z, Akimbekov N, Wu X. Lysostaphin: Engineering and Potentiation toward Better Applications. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11441-11457. [PMID: 36082619 DOI: 10.1021/acs.jafc.2c03459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Lysostaphin is a potent bacteriolytic enzyme with endopeptidase activity against the common pathogen Staphylococcus aureus. By digesting the pentaglycine crossbridge in the cell wall peptidoglycan of S. aureus including the methicillin-resistant strains, lysostaphin initiates rapid lysis of planktonic and sessile cells (biofilms) and has great potential for use in agriculture, food industries, and pharmaceutical industries. In the past few decades, there have been tremendous efforts in potentiating lysostaphin for better applications in these fields, including engineering of the enzyme for higher potency and lower immunogenicity with longer-lasting effects, formulation and immobilization of the enzyme for higher stability and better durability, and recombinant expression for low-cost industrial production and in situ biocontrol. These achievements are extensively reviewed in this article focusing on applications in disease control, food preservation, surface decontamination, and pathogen detection. In addition, some basic properties of lysostaphin that have been controversial and only elucidated recently are summarized, including the substrate-binding properties, the number of zinc-binding sites, the substrate range, and the cleavage site in the pentaglycine crossbridge. Resistance to lysostaphin is also highlighted with a focus on various mechanisms. This article is concluded with a discussion on the limitations and future perspectives for the actual applications of lysostaphin.
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Affiliation(s)
- Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Jingyuan Li
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Zheng Su
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Nuraly Akimbekov
- Department of Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
| | - Xia Wu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
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12
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Miek L, Jordan PM, Günther K, Pace S, Beyer T, Kowalak D, Hoerr V, Löffler B, Tuchscherr L, Serhan CN, Gerstmeier J, Werz O. Staphylococcus aureus controls eicosanoid and specialized pro-resolving mediator production via lipoteichoic acid. Immunology 2022; 166:47-67. [PMID: 35143048 PMCID: PMC9426618 DOI: 10.1111/imm.13449] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus causes severe infections associated with inflammation, such as sepsis or osteomyelitis. Inflammatory processes are regulated by distinct lipid mediators (LMs) but how their biosynthetic pathways are orchestrated in S. aureus infections is elusive. We show that S. aureus strikingly not only modulates pro-inflammatory, but also inflammation-resolving LM pathways in murine osteomyelitis and osteoclasts as well as in human monocyte-derived macrophages (MDMs) with different phenotype. Targeted LM metabololipidomics using ultra-performance liquid chromatography-tandem mass spectrometry revealed massive generation of LM with distinct LM signature profiles in acute and chronic phases of S. aureus-induced murine osteomyelitis in vivo. In human MDM, S. aureus elevated cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1), but impaired the levels of 15-lipoxygenase-1 (15-LOX-1), with respective changes in LM signature profiles initiated by these enzymes, that is, elevated PGE2 and impaired specialized pro-resolving mediators, along with reduced M2-like phenotypic macrophage markers. The cell wall component, lipoteichoic acid (LTA), mimicked the impact of S. aureus elevating COX-2/mPGES-1 expression via NF-κB and p38 MAPK signalling in MDM, while the impairment of 15-LOX-1 correlates with reduced expression of Lamtor1. In conclusion, S. aureus dictates LM pathways via LTA resulting in a shift from anti-inflammatory M2-like towards pro-inflammatory M1-like LM signature profiles.
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Affiliation(s)
- Laura Miek
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Paul M. Jordan
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Kerstin Günther
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Simona Pace
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Timo Beyer
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - David Kowalak
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Verena Hoerr
- Institute of Medical MicrobiologyJena University HospitalJenaGermany
| | - Bettina Löffler
- Institute of Medical MicrobiologyJena University HospitalJenaGermany
| | - Lorena Tuchscherr
- Institute of Medical MicrobiologyJena University HospitalJenaGermany
| | - Charles N. Serhan
- Department of Anesthesiology, Perioperative and Pain MedicineHarvard Medical SchoolCenter for Experimental Therapeutics and Reperfusion InjuryBrigham and Women’s HospitalBostonMassachusettsUSA
| | - Jana Gerstmeier
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
| | - Oliver Werz
- Department of Pharmaceutical/Medicinal ChemistryInstitute of PharmacyFriedrich‐Schiller‐University JenaJenaGermany
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13
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Yang D, Wang S, Sun E, Chen Y, Hua L, Wang X, Zhou R, Chen H, Peng Z, Wu B. A temperate Siphoviridae bacteriophage isolate from Siberian tiger enhances the virulence of methicillin-resistant Staphylococcus aureus through distinct mechanisms. Virulence 2022; 13:137-148. [PMID: 34986751 PMCID: PMC8741283 DOI: 10.1080/21505594.2021.2022276] [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] [Indexed: 11/12/2022] Open
Abstract
The emergence and worldwide spread of Methicillin-resistant Staphylococcus aureus (MRSA) pose a threat to human health. While bacteriophages are recognized as an effective alternative to treat infections caused by drug resistant pathogens, some bacteriophages in particular the temperate bacteriophage may also influence the virulence of the host bacteria in distinct ways. In this study, we isolated a bacteriophage vB_Saus_PHB21 from an epidermal sample of Siberian tiger (Panthera tigris altaica) using an MRSA strain SA14 as the indicator. Our following laboratory tests and whole genome sequencing analyses revealed that vB_Saus_PHB21 was a temperate bacteriophage belonging to the Siphoviridae family, and this bacteriophage did not contain any virulence genes. However, the integration of PHB21 genome into the host MRSA increased the bacterial capacities of cell adhesion, anti-phagocytosis, and biofilm formation. Challenge of the lysogenic strain (SA14+) caused severe mortalities in both Galleria mellonella and mouse models. Mice challenged with SA14+ showed more serious organ lesions and produced higher inflammatory cytokines (IL-8, IFN-γ and TNF-α) compared to those challenged with SA14. In mechanism, we found the integration of PHB21 genome caused the upregulated expression of many genes encoding products involved in bacterial biofilm formation, adherence to host cells, anti-phagocytosis, and virulence. This study may provide novel knowledge of “bacteria-phage-interactions” in MRSA.
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Affiliation(s)
- Dan Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Shuang Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Erchao Sun
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Yibao Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Lin Hua
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Xiangru Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Zhong Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
| | - Bin Wu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Microbiology, Huazhong Agricultural University, Wuhan, China.,Ministry of Agriculture and Rural Affairs Key Laboratory of Development of Veterinary Diagnostic Products, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Ministry of Science and Technology International Research Center for Animal Disease, Huazhong Agricultural University, Wuhan, China
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14
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Akinsola RO, Adewoyin M, Lee CW, Sim EUH, Narayanan K. RFP-based method for real-time tracking of invasive bacteria in a heterogeneous population of cells. Anal Biochem 2021; 634:114432. [PMID: 34695391 DOI: 10.1016/j.ab.2021.114432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 09/02/2021] [Accepted: 10/19/2021] [Indexed: 10/20/2022]
Abstract
Quantification of bacterial invasion into eukaryotic cells is a prerequisite to unfold the molecular mechanisms of this vector's function to obtain insights for improving its efficiency. Invasion is traditionally quantified by antibiotic protection assays that require dilution plating and counting of colony-forming units rescued from infected cells. However, to differentiate between attached and internalized bacteria vector, this assay requires supplementation by a time-consuming and tedious immunofluorescence staining, making it laborious and reduces its reliability and reproducibility. Here we describe a new red fluorescent protein (RFP)-based high-throughput and inexpensive method for tracking bacterial adherence and internalization through flow cytometry to provide a convenient and real-time quantification of bacterial invasiveness in a heterogeneous population of cells. We invaded MCF-7, A549, and HEK-293 cells with the E. coli vector and measured RFP using imaging flow cytometry. We found high cellular infection of up to 70.47% in MCF-7 compared to 27.4% and 26.2% in A549 and HEK-293 cells, respectively. The quantitative evaluation of internalized E. coli is rapid and cell-dependent, and it distinctively differentiates between attached and cytosolic bacteria while showing the degree of cellular invasiveness. This imaging flow cytometry approach can be applied broadly to study host-bacteria interaction.
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Affiliation(s)
- Rasaq Olajide Akinsola
- School of Science, Monash University Malaysia, Bandar Sunway 47500, Selangor Darul Ehsan, Malaysia
| | - Malik Adewoyin
- Faculty of Dentistry, Universiti Kebangsaan Malaysia Jalan Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia
| | - Choon-Weng Lee
- Institute of Biological Sciences, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Edmund Ui-Hang Sim
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Sarawak, Malaysia
| | - Kumaran Narayanan
- School of Science, Monash University Malaysia, Bandar Sunway 47500, Selangor Darul Ehsan, Malaysia.
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15
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Zhou K, Mi K, Ma W, Xu X, Huo M, Algharib SA, Pan Y, Xie S, Huang L. Application of physiologically based pharmacokinetic models to promote the development of veterinary drugs with high efficacy and safety. J Vet Pharmacol Ther 2021; 44:663-678. [PMID: 34009661 DOI: 10.1111/jvp.12976] [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] [Received: 03/01/2021] [Revised: 10/27/2020] [Accepted: 04/18/2021] [Indexed: 12/12/2022]
Abstract
Physiologically based pharmacokinetic (PBPK) models have become important tools for the development of novel human drugs. Food-producing animals and pets comprise an important part of human life, and the development of veterinary drugs (VDs) has greatly impacted human health. Owing to increased affordability of and demand for drug development, VD manufacturing companies should have more PBPK models required to reduce drug production costs. So far, little attention has been paid on applying PBPK models for the development of VDs. This review begins with the development processes of VDs; then summarizes case studies of PBPK models in human or VD development; and analyzes the application, potential, and advantages of PBPK in VD development, including candidate screening, formulation optimization, food effects, target-species safety, and dosing optimization. Then, the challenges of applying the PBPK model to VD development are discussed. Finally, future opportunities of PBPK models in designing dosing regimens for intracellular pathogenic infections and for efficient oral absorption of VDs are further forecasted. This review will be relevant to readers who are interested in using a PBPK model to develop new VDs.
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Affiliation(s)
- Kaixiang Zhou
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Kun Mi
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Wenjin Ma
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Xiangyue Xu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Meixia Huo
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China
| | - Samah Attia Algharib
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China.,Department of Clinical Pathology, Faculty of Veterinary Medicine, Benha University, Moshtohor, Toukh, Egypt
| | - Yuanhu Pan
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, China
| | - Shuyu Xie
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, China
| | - Lingli Huang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, China
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16
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Batool N, Shamim A, Chaurasia AK, Kim KK. Genome-Wide Analysis of Staphylococcus aureus Sequence Type 72 Isolates Provides Insights Into Resistance Against Antimicrobial Agents and Virulence Potential. Front Microbiol 2021; 11:613800. [PMID: 33552024 PMCID: PMC7854921 DOI: 10.3389/fmicb.2020.613800] [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: 10/03/2020] [Accepted: 12/17/2020] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus sequence type 72 (ST72) is a major community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) that has rapidly entered the hospital setting in Korea, causing mild superficial skin wounds to severe bloodstream infections. In this study, we sequenced and analyzed the genomes of one methicillin-resistant human isolate and one methicillin-sensitive human isolate of ST72 from Korea, K07-204 and K07-561, respectively. We used a subtractive genomics approach to compare these two isolates to other 27 ST72 isolates to investigate antimicrobial resistance (AMR) and virulence potential. Furthermore, we validated genotypic differences by phenotypic characteristics analysis. Comparative and subtractive genomics analysis revealed that K07-204 contains methicillin (mecA), ampicillin (blaZ), erythromycin (ermC), aminoglycoside (aadD), and tetracycline (tet38, tetracycline efflux pump) resistance genes while K07-561 has ampicillin (blaZ) and tetracycline (tet38) resistance genes. In addition to antibiotics, K07-204 was reported to show resistance to lysostaphin treatment. K07-204 also has additional virulence genes (adsA, aur, hysA, icaABCDR, lip, lukD, sdrC, and sdrE) compared to K07-561, which may explain the differential virulence potential of these human isolates of ST72. Unexpectedly, the virulence potential of K07-561 was higher in an in vivo wax-worm infection model than that of K07-204, putatively due to the presence of a 20-fold higher staphyloxanthin concentration than K07-204. Comprehensive genomic analysis of these two human isolates, with 27 ST72 isolates, and S. aureus USA300 (ST8) suggested that acquisition of both virulence and antibiotics resistance genes by ST72 isolates might have facilitated their adaptation from a community to a hospital setting where the selective pressure imposed by antibiotics selects for more resistant and virulent isolates. Taken together, the results of the current study provide insight into the genotypic and phenotypic features of various ST72 clones across the globe, delivering more options for developing therapeutics and rapid molecular diagnostic tools to detect resistant bacteria.
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Affiliation(s)
- Nayab Batool
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Amen Shamim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Akhilesh Kumar Chaurasia
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, South Korea.,Institute of Antimicrobial Resistance and Therapeutics (IAMRT), Sungkyunkwan University (SKKU), Suwon, South Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, South Korea.,Institute of Antimicrobial Resistance and Therapeutics (IAMRT), Sungkyunkwan University (SKKU), Suwon, South Korea.,Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Samsung Medical Center (SMC), Sungkyunkwan University School of Medicine, Seoul, South Korea
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17
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Draft Genome Sequences of Lysostaphin-Resistant (K07-204) and Lysostaphin-Susceptible (K07-561) Staphylococcus aureus Sequence Type 72 Strains Isolated from Patients in South Korea. Microbiol Resour Announc 2020; 9:9/49/e01057-20. [PMID: 33272992 PMCID: PMC7714846 DOI: 10.1128/mra.01057-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus sequence type 72 (ST72) is prevalent in South Korea and has shown resistance to multiple antimicrobials. ST72 isolates display different levels of resistance to the antistaphylococcal lysostaphin. Draft genome sequencing of ST72 human isolates exhibiting lysostaphin resistance or susceptibility was performed to better understand the mechanism of lysostaphin resistance using subtractive genomics. Methicillin-resistant Staphylococcus aureus sequence type 72 (ST72) is prevalent in South Korea and has shown resistance to multiple antimicrobials. ST72 isolates display different levels of resistance to the antistaphylococcal lysostaphin. Draft genome sequencing of ST72 human isolates exhibiting lysostaphin resistance or susceptibility was performed to better understand the mechanism of lysostaphin resistance using subtractive genomics.
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18
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Functional Identification of Serine Hydroxymethyltransferase as a Key Gene Involved in Lysostaphin Resistance and Virulence Potential of Staphylococcus aureus Strains. Int J Mol Sci 2020; 21:ijms21239135. [PMID: 33266291 PMCID: PMC7731198 DOI: 10.3390/ijms21239135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/22/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
Gaining an insight into the mechanism underlying antimicrobial-resistance development in Staphylococcus aureus is crucial for identifying effective antimicrobials. We isolated S. aureus sequence type 72 from a patient in whom the S. aureus infection was highly resistant to various antibiotics and lysostaphin, but no known resistance mechanisms could explain the mechanism of lysostaphin resistance. Genome-sequencing followed by subtractive and functional genomics revealed that serine hydroxymethyltransferase (glyA or shmT gene) plays a key role in lysostaphin resistance. Serine hydroxymethyltransferase (SHMT) is indispensable for the one-carbon metabolism of serine/glycine interconversion and is linked to folate metabolism. Functional studies revealed the involvement of SHMT in lysostaphin resistance, as ΔshmT was susceptible to the lysostaphin, while complementation of the knockout expressing shmT restored resistance against lysostaphin. In addition, the ΔshmT showed reduced virulence under in vitro (mammalian cell lines infection) and in vivo (wax-worm infection) models. The SHMT inhibitor, serine hydroxymethyltransferase inhibitor 1 (SHIN1), protected the 50% of the wax-worm infected with wild type S. aureus. These results suggest SHMT is relevant to the extreme susceptibility to lysostaphin and the host immune system. Thus, the current study established that SHMT plays a key role in lysostaphin resistance development and in determining the virulence potential of multiple drug-resistant S. aureus.
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19
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Gautam S, Stahl Y, Young GM, Howell R, Cohen AJ, Tsang DA, Martin T, Sharma L, Dela Cruz CS. Quantification of bronchoalveolar neutrophil extracellular traps and phagocytosis in murine pneumonia. Am J Physiol Lung Cell Mol Physiol 2020; 319:L661-L669. [PMID: 32783617 DOI: 10.1152/ajplung.00316.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The past two decades have witnessed a resurgence in neutrophil research, inspired in part by the discovery of neutrophil extracellular traps (NETs) and their myriad roles in health and disease. Within the lung, dysregulation of neutrophils and NETosis have been linked to an array of diseases including pneumonia, cystic fibrosis, acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and severe asthma. However, our understanding of pathologic neutrophil responses in the lung remains incomplete. Two methodologic issues have contributed to this gap: first, an emphasis on studying neutrophils from blood rather than the lung and second, the technical difficulties of interrogating neutrophil responses in mice, which has largely restricted basic murine research to specialized laboratories. To address these limitations, we have developed a suite of techniques for studying neutrophil effector functions specifically in the mouse lung. These include ex vivo assays for phagocytosis and NETosis using bronchoalveolar neutrophils and in situ evaluation of NETosis in a murine model of pneumonia. Throughout, we have prioritized technical ease and robust, quantitative readouts. We hope these assays will help to standardize research on lung neutrophils and improve accessibility to this burgeoning field.
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Affiliation(s)
- Samir Gautam
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Yannick Stahl
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Grant M Young
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Rebecca Howell
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - Avi J Cohen
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Derek A Tsang
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Tommy Martin
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Lokesh Sharma
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut
| | - Charles S Dela Cruz
- Yale School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University, New Haven, Connecticut.,Yale School of Medicine, Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut
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20
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Roles of the Site 2 Protease Eep in Staphylococcus aureus. J Bacteriol 2020; 202:JB.00046-20. [PMID: 32457050 DOI: 10.1128/jb.00046-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/21/2020] [Indexed: 01/02/2023] Open
Abstract
In Enterococcus faecalis, the site 2 protease Eep generates sex pheromones, including cAM373. Intriguingly, in Staphylococcus aureus, a peptide similar to cAM373, named cAM373_SA, is produced from the camS gene. Here, we report that the staphylococcal Eep homolog is not only responsible for the production of cAM373_SA but also critical for staphylococcal virulence. As with other Eep proteins, the staphylococcal Eep protein has four transmembrane (TM) domains, with the predicted zinc metalloprotease active site (HEXXH) in the first TM domain. eep deletion reduced the cAM373_SA activity in the culture supernatant to the level of the camS deletion mutant. It also markedly decreased the cAM373 peptide peak in a high-performance liquid chromatography (HPLC) analysis. Proteomics analysis showed that Eep affects the production and/or the release of diverse proteins, including the signal peptidase subunit SpsB and the surface proteins SpA, SasG, and FnbA. eep deletion decreased the adherence of S. aureus to host epithelial cells; however, the adherence of the eep mutant was increased by overexpression of the surface proteins SpA, SasG, and FnbA. eep deletion reduced staphylococcal resistance to killing by human neutrophils as well as survival in a murine model of blood infection. The overexpression of the surface protein SpA in the eep mutant increased bacterial survival in the liver. Our study illustrates that in S. aureus, Eep not only generates cAM373_SA but also contributes to the survival of the bacterial pathogen in the host.IMPORTANCE The emergence of multidrug-resistant Staphylococcus aureus makes the treatment of staphylococcal infections much more difficult. S. aureus can acquire a drug resistance gene from other bacteria, such as Enterococcus faecalis Intriguingly, S. aureus produces a sex pheromone for the E. faecalis plasmid pAM373, raising the possibility that S. aureus actively promotes plasmid conjugation from E. faecalis In this study, we found that the staphylococcal Eep protein is responsible for sex pheromone processing and contributes to the survival of the bacteria in the host. These results will enhance future research on the drug resistance acquisition of S. aureus and can lead to the development of novel antivirulence drugs.
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21
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Stoneham SM, Cantillon DM, Waddell SJ, Llewelyn MJ. Spontaneously Occurring Small-Colony Variants of Staphylococcus aureus Show Enhanced Clearance by THP-1 Macrophages. Front Microbiol 2020; 11:1300. [PMID: 32595630 PMCID: PMC7303551 DOI: 10.3389/fmicb.2020.01300] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/20/2020] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a common cause of chronic and relapsing infection, especially when the ability of the immune system to sterilize a focus of infection is compromised (e.g., because of a foreign body or in the cystic fibrosis lung). Chronic infections are associated with slow-growing colony phenotypes of S. aureus on solid media termed small-colony variants (SCVs). Stable SCVs show characteristic mutations in the electron transport chain that convey resistance to antibiotics, particularly aminoglycosides. This can be used to identify SCVs from within mixed-colony phenotype populations of S. aureus. More recently, populations of SCVs that rapidly revert to a “wild-type” (WT) colony phenotype, in the absence of selection pressure, have also been described. In laboratory studies, SCVs accumulate through prolonged infection of non-professional phagocytes and may represent an adaptation to the intracellular environment. However, data from phagocytic cells are lacking. In this study, we mapped SCV and WT colony populations in axenic growth of multiple well-characterized methicillin-sensitive and methicillin-resistant S. aureus strains. We identified SCVs populations on solid media both in the presence and absence of gentamicin. We generated stable SCVs from Newman strain S. aureus, and infected human macrophages with WT S. aureus (Newman, 8325-4) and their SCV counterparts (SCV3, I10) to examine intracellular formation and survival of SCVs. We show that SCVs arise spontaneously during axenic growth, and that the ratio of SCV:WT morphology differs between strains. Exposure to the intracellular environment of human macrophages did not increase formation of SCVs over 5 days and macrophages were able to clear stable SCV bacteria more effectively than their WT counterparts.
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Affiliation(s)
- Simon M Stoneham
- Department of Microbiology and Infection, Royal Sussex County Hospital, Brighton, United Kingdom.,Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Daire M Cantillon
- Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Simon J Waddell
- Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Martin J Llewelyn
- Department of Microbiology and Infection, Royal Sussex County Hospital, Brighton, United Kingdom.,Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
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22
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Evaluation of the Activity of a Combination of Three Bacteriophages Alone or in Association with Antibiotics on Staphylococcus aureus Embedded in Biofilm or Internalized in Osteoblasts. Antimicrob Agents Chemother 2020; 64:AAC.02231-19. [PMID: 31871084 DOI: 10.1128/aac.02231-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/18/2019] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus is responsible for difficult-to-treat bone and joint infections (BJIs). This is related to its ability to form biofilm and to be internalized and persist inside osteoblasts. Recently, bacteriophage therapy has emerged as a promising option to improve treatment of such infections, but data on its activity against the specific bacterial lifestyles presented above remain scarce. We evaluated the activity of a combination of three bacteriophages, recently used for compassionate treatment in France, against S. aureus HG001 in a model of staphylococcal biofilm and a model of osteoblasts infection, alone or in association with vancomycin or rifampin. The activity of bacteriophages against biofilm-embedded S. aureus was dose dependent. In addition, synergistic effects were observed when bacteriophages were combined with antibiotics used at the lowest concentrations. Phage penetration into osteoblasts was observed only when the cells were infected, suggesting a S. aureus-dependent Trojan horse mechanism for internalization. The intracellular bacterial count of bacteria in infected osteoblasts treated with bacteriophages as well as with vancomycin was significantly higher than in cells treated with lysostaphin, used as a control condition, owing to the absence of intracellular activity and the rapid killing of bacteria released after the death of infected cells. These results suggest that bacteriophages are both inactive in the intracellular compartment after being internalized in infected osteoblasts and present a delayed killing effect on bacteria released after cell lysis into the extracellular compartment, which avoids preventing them from infecting other osteoblasts. The combination of bacteriophages tested was highly active against S. aureus embedded in biofilm but showed no activity against intracellular bacteria in the cell model used.
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23
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Nguyen T, Kim T, Ta HM, Yeo WS, Choi J, Mizar P, Lee SS, Bae T, Chaurasia AK, Kim KK. Targeting Mannitol Metabolism as an Alternative Antimicrobial Strategy Based on the Structure-Function Study of Mannitol-1-Phosphate Dehydrogenase in Staphylococcus aureus. mBio 2019; 10:e02660-18. [PMID: 31289190 PMCID: PMC6623548 DOI: 10.1128/mbio.02660-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/05/2019] [Indexed: 11/22/2022] Open
Abstract
Mannitol-1-phosphate dehydrogenase (M1PDH) is a key enzyme in Staphylococcus aureus mannitol metabolism, but its roles in pathophysiological settings have not been established. We performed comprehensive structure-function analysis of M1PDH from S. aureus USA300, a strain of community-associated methicillin-resistant S. aureus, to evaluate its roles in cell viability and virulence under pathophysiological conditions. On the basis of our results, we propose M1PDH as a potential antibacterial target. In vitro cell viability assessment of ΔmtlD knockout and complemented strains confirmed that M1PDH is essential to endure pH, high-salt, and oxidative stress and thus that M1PDH is required for preventing osmotic burst by regulating pressure potential imposed by mannitol. The mouse infection model also verified that M1PDH is essential for bacterial survival during infection. To further support the use of M1PDH as an antibacterial target, we identified dihydrocelastrol (DHCL) as a competitive inhibitor of S. aureus M1PDH (SaM1PDH) and confirmed that DHCL effectively reduces bacterial cell viability during host infection. To explain physiological functions of SaM1PDH at the atomic level, the crystal structure of SaM1PDH was determined at 1.7-Å resolution. Structure-based mutation analyses and DHCL molecular docking to the SaM1PDH active site followed by functional assay identified key residues in the active site and provided the action mechanism of DHCL. Collectively, we propose SaM1PDH as a target for antibiotic development based on its physiological roles with the goals of expanding the repertory of antibiotic targets to fight antimicrobial resistance and providing essential knowledge for developing potent inhibitors of SaM1PDH based on structure-function studies.IMPORTANCE Due to the shortage of effective antibiotics against drug-resistant Staphylococcus aureus, new targets are urgently required to develop next-generation antibiotics. We investigated mannitol-1-phosphate dehydrogenase of S. aureus USA300 (SaM1PDH), a key enzyme regulating intracellular mannitol levels, and explored the possibility of using SaM1PDH as a target for developing antibiotic. Since mannitol is necessary for maintaining the cellular redox and osmotic potential, the homeostatic imbalance caused by treatment with a SaM1PDH inhibitor or knockout of the gene encoding SaM1PDH results in bacterial cell death through oxidative and/or mannitol-dependent cytolysis. We elucidated the molecular mechanism of SaM1PDH and the structural basis of substrate and inhibitor recognition by enzymatic and structural analyses of SaM1PDH. Our results strongly support the concept that targeting of SaM1PDH represents an alternative strategy for developing a new class of antibiotics that cause bacterial cell death not by blocking key cellular machinery but by inducing cytolysis and reducing stress tolerance through inhibition of the mannitol pathway.
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Affiliation(s)
- Thanh Nguyen
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Truc Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Hai Minh Ta
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Won Sik Yeo
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Jongkeun Choi
- Department of Chemical Engineering, Chungwoon University, Incheon, South Korea
| | - Pushpak Mizar
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Seung Seo Lee
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Akhilesh Kumar Chaurasia
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
- Samsung Biomedical Research Institute, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
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