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Bhattacharya M, Horswill AR. The role of human extracellular matrix proteins in defining Staphylococcus aureus biofilm infections. FEMS Microbiol Rev 2024; 48:fuae002. [PMID: 38337187 PMCID: PMC10873506 DOI: 10.1093/femsre/fuae002] [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: 07/19/2023] [Revised: 01/26/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024] Open
Abstract
Twenty to forty one percent of the world's population is either transiently or permanently colonized by the Gram-positive bacterium, Staphylococcus aureus. In 2017, the CDC designated methicillin-resistant S. aureus (MRSA) as a serious threat, reporting ∼300 000 cases of MRSA-associated hospitalizations annually, resulting in over 19 000 deaths, surpassing that of HIV in the USA. S. aureus is a proficient biofilm-forming organism that rapidly acquires resistance to antibiotics, most commonly methicillin (MRSA). This review focuses on a large group of (>30) S. aureus adhesins, either surface-associated or secreted that are designed to specifically bind to 15 or more of the proteins that form key components of the human extracellular matrix (hECM). Importantly, this includes hECM proteins that are pivotal to the homeostasis of almost every tissue environment [collagen (skin), proteoglycans (lung), hemoglobin (blood), elastin, laminin, fibrinogen, fibronectin, and fibrin (multiple organs)]. These adhesins offer S. aureus the potential to establish an infection in every sterile tissue niche. These infections often endure repeated immune onslaught, developing into chronic, biofilm-associated conditions that are tolerant to ∼1000 times the clinically prescribed dose of antibiotics. Depending on the infection and the immune response, this allows S. aureus to seamlessly transition from colonizer to pathogen by subtly manipulating the host against itself while providing the time and stealth that it requires to establish and persist as a biofilm. This is a comprehensive discussion of the interaction between S. aureus biofilms and the hECM. We provide particular focus on the role of these interactions in pathogenesis and, consequently, the clinical implications for the prevention and treatment of S. aureus biofilm infections.
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Affiliation(s)
- Mohini Bhattacharya
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
- Department of Veterans Affairs, Eastern Colorado Health Care System, Aurora, CO 80045, United States
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Verdenius CY, Broens EM, Slenter IJM, Djajadiningrat-Laanen SC. Corneal stromal ulcerations in a referral population of dogs and cats in the Netherlands (2012-2019): Bacterial isolates and antibiotic resistance. Vet Ophthalmol 2024; 27:7-16. [PMID: 36878893 DOI: 10.1111/vop.13080] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/11/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023]
Abstract
OBJECTIVE To evaluate bacterial isolates from corneal stromal ulcerations in dogs and cats in the Netherlands, review their antibiotic susceptibility, determine whether recent topical treatment affected bacterial culture results, and investigate whether (multi-drug) resistance patterns changed over time. ANIMALS STUDIED Client-owned dogs and cats were diagnosed with corneal stromal ulceration at the Utrecht University Clinic for Companion Animals between 2012 and 2019. PROCEDURES Retrospective analysis. RESULTS In total, 163 samples were collected from 122 dogs (130 samples) and 33 cats. Positive cultures were obtained from 76 canine and 13 feline samples (59% and 39%, respectively) and included Staphylococcus (42 in dogs, 8 in cats), Streptococcus (22 in dogs, 2 in cats), and Pseudomonas (9 in dogs, 1 in cats) species. Significantly fewer positive cultures were found in dogs and cats previously treated with topical antibiotics (χ2 = 6.52, p = .011 and χ2 = 4.27, p = .039, respectively). Bacterial resistance to chloramphenicol was more common in dogs previously treated with chloramphenicol (χ2 = 5.24, p = .022). The incidence of acquired antibiotic resistance did not increase significantly over time. In dogs, the incidence of multi-drug-resistant isolates increased significantly between 2012-2015 and 2016-2019 (9.4% vs. 38.6%, p = .0032). CONCLUSIONS Staphylococcus, Streptococcus, and Pseudomonas species were the most common bacteria associated with canine and feline corneal stromal ulcerations. Previous treatment with antibiotics affected bacterial culture results and antibiotic sensitivity. Although the overall incidence of acquired antibiotic resistance did not change over time, the incidence of multi-drug-resistant isolates in dogs increased over an 8-year period.
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Affiliation(s)
- Clara Y Verdenius
- Division of Surgery of Companion Animals - Ophthalmology Section, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Els M Broens
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Inge J M Slenter
- Division of Surgery of Companion Animals - Ophthalmology Section, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Sylvia C Djajadiningrat-Laanen
- Division of Surgery of Companion Animals - Ophthalmology Section, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Shanks RMQ, Atta S, Stella NA, Sundar-Raj CV, Romanowski JE, Grewal AS, Shanks HQ, Mumper SM, Dhaliwal DK, Mammen A, Callaghan JD, Calvario RC, Romanowski EG, Kowalski RP, Zegans ME, Jhanji V. A rise in the frequency of lasR mutant Pseudomonas aeruginosa among keratitis isolates between 1993 and 2021. Front Cell Infect Microbiol 2023; 13:1286842. [PMID: 38029269 PMCID: PMC10651084 DOI: 10.3389/fcimb.2023.1286842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Pseudomonas aeruginosa causes vision threatening keratitis. The LasR transcription factor regulates virulence factors in response to the quorum sensing molecule N-3-oxo-dodecanoyl-L-homoserine lactone. P. aeruginosa isolates with lasR mutations are characterized by an iridescent high sheen phenotype caused by a build-up of 2-heptyl-4-quinolone. A previous study demonstrated 22% (n=101) of P. aeruginosa keratitis isolates from India between 2010 and 2016 were sheen positive lasR mutants, and the sheen phenotype correlated with worse clinical outcomes for patients. In this study, a longitudinal collection of P. aeruginosa keratitis isolates from Eastern North America were screened for lasR mutations by the sheen phenotype and sequencing of the lasR gene. Methods Keratitis isolates (n=399) were classified by sheen phenotype. The lasR gene was cloned from a subset of isolates, sequenced, and tested for loss of function or dominant-negative status based on an azocasein protease assay. A retrospective chart review compared outcomes of keratitis patients infected by sheen positive and negative isolates. Results A significant increase in sheen positive isolates was observed between 1993 and 2021. Extracellular protease activity was reduced among the sheen positive isolates and a defined lasR mutant. Cloned lasR alleles from the sheen positive isolates were loss of function or dominant negative and differed in sequence from previously reported ocular lasR mutant alleles. Retrospective analysis of patient information suggested significantly better visual outcomes for patients infected by sheen positive isolates. Discussion These results indicate an increase in lasR mutations among keratitis isolates in the United States and suggest that endemic lasR mutants can cause keratitis.
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Affiliation(s)
- Robert M. Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Sarah Atta
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Nicholas A. Stella
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Chollapadi V. Sundar-Raj
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - John E. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Arman S. Grewal
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Hazel Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Sonya M. Mumper
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Deepinder K. Dhaliwal
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Alex Mammen
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jake D. Callaghan
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rachel C. Calvario
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Eric G. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Regis P. Kowalski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Michael E. Zegans
- Department of Surgery, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Vishal Jhanji
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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Saad ZA, Elnashar H, Negm S, Elsayed HA, Abdallah MG, Abuamara TMM, Abd-Elhay WM, Elghonemy HM. Collagen cross-linking as monotherapy in experimentally induced corneal abscess in rabbits. BMC Ophthalmol 2023; 23:266. [PMID: 37312088 PMCID: PMC10262482 DOI: 10.1186/s12886-023-03007-y] [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: 07/26/2022] [Accepted: 05/31/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Collagen cross-linking (CXL) has evolved as an essential therapeutic approach for corneal infections, allowing for rapidly eliminating the infecting microorganism while reducing inflammation. This study aims to evaluate the efficacy of CXL as a monotherapy for managing infectious keratitis caused by Fusarium solani and Pseudomonas aeruginosa. MATERIALS AND METHODS Forty-eight white New Zealand rabbits weighing approximately 1.5-2 KG were included. The cornea of one eye of each rabbit was inoculated with either Fusarium solani or Pseudomonas aeruginosa. Group A served as a control and was subdivided into two subgroups, A1 and A2; each subgroup consisted of 8 eyes and was injected with either Fusarium solani or Pseudomonas aeruginosa, respectively. Group B (16 eyes) was inoculated with Fusarium solani, while group C (16 eyes) were inoculated with Pseudomonas aeruginosa. All animals in Group B and C received CXL treatment one week after inoculation of the organisms and after corneal abscess formation was confirmed. At the same time, animals in Group A were left untreated. RESULTS There was a statistically significant reduction in the number of colony-forming units (CFU) in Group B following CXL. No growth existed in any samples at the end of the 4th week. There was a statistically significant difference in the number of CFU between group B and the control group (p < 0.001). In group C, there was a statistically significant reduction in the CFU at the end of the first week after CXL. However, there was regrowth in all samples afterward. All 16 models in Group C showed uncountable and extensive growth during the subsequent follow-ups. There was no statistically significant difference between the number of CFU in Group C and the control group. Histopathology showed lesser corneal melting in CXL-treated Pseudomonas aeruginosa. CONCLUSIONS Collagen cross-linking is promising monotherapy and alternative treatment in managing infective keratitis caused by Fusarium solani but is less effective in Pseudomonas aeruginosa as monotherapy.
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Affiliation(s)
- Zeinab A Saad
- Memorial Institute of Ophthalmic Research, Giza, 12511, Egypt.
| | - Hazem Elnashar
- Memorial Institute of Ophthalmic Research, Giza, 12511, Egypt
| | - Sahar Negm
- Research Institute of Ophthalmology, Giza, Egypt
| | - Hala A Elsayed
- Memorial Institute of Ophthalmic Research, Giza, 12511, Egypt
| | - Mohamed Gaber Abdallah
- Faculty of Medicine, Department of Medical Biochemistry, Al-Azhar University, Cairo, Egypt
| | - Tamer M M Abuamara
- Faculty of Medicine, Histology Department, Al-Azhar University, Cairo, Egypt
| | - Wagih M Abd-Elhay
- Faculty of Medicine, Histology Department, Al-Azhar University, Cairo, Egypt
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Stella NA, Romanowski EG, Brothers KM, Calvario RC, Shanks RMQ. IgaA Protein, GumB, Has a Global Impact on the Transcriptome and Surface Proteome of Serratia marcescens. Infect Immun 2022; 90:e0039922. [PMID: 36317876 PMCID: PMC9671016 DOI: 10.1128/iai.00399-22] [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: 09/07/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022] Open
Abstract
Bacterial stress response signaling systems, like the Rcs system are triggered by membrane and cell wall damaging compounds, including antibiotics and immune system factors. These regulatory systems help bacteria survive envelope stress by altering the transcriptome resulting in protective phenotypic changes that may also influence the virulence of the bacterium. This study investigated the role of the Rcs stress response system using a clinical keratitis isolate of Serratia marcescens with a mutation in the gumB gene. GumB, an IgaA ortholog, inhibits activation of the Rcs system, such that mutants have overactive Rcs signaling. Transcriptomic analysis indicated that approximately 15% of all S. marcescens genes were significantly altered with 2-fold or greater changes in expression in the ΔgumB mutant compared to the wild type, indicating a global transcriptional regulatory role for GumB. We further investigated the phenotypic consequences of two classes of genes with altered expression in the ΔgumB mutant expected to contribute to infections: serralysin metalloproteases PrtS, SlpB, and SlpE, and type I pili coded by fimABCD. Secreted fractions from the ΔgumB mutant had reduced cytotoxicity to a corneal cell line, and could be complemented by induced expression of prtS, but not cytolysin shlBA, phospholipase phlAB, or flagellar master regulator flhDC operons. Proteomic analysis, qRT-PCR, and type I pili-dependent yeast agglutination indicated an inhibitory role for the Rcs system in adhesin production. Together these data demonstrate GumB has a global impact on S. marcescens gene expression that had measurable effects on bacterial cytotoxicity and surface adhesin production.
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Affiliation(s)
- Nicholas A. Stella
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Eric G. Romanowski
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Kimberly M. Brothers
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Rachel C. Calvario
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
| | - Robert M. Q. Shanks
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, USA
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Corneal cross-linking guards against infectious keratitis: an experimental model. Int Ophthalmol 2022; 43:1241-1248. [PMID: 36255611 PMCID: PMC10113293 DOI: 10.1007/s10792-022-02522-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 09/11/2022] [Indexed: 10/24/2022]
Abstract
BACKGROUND PACK-CXL (photo-activated chromophore for keratitis-corneal cross-linking) is an alternative option in treatment of corneal infections. It inhibits corneal melting by increasing the stromal resistance, besides the microbicidal effect of photo-activated riboflavin. METHODS Corneal infection with Pseudomonas aeruginosa and Staph aureus bacteria was induced in 20 eyes of 10 rabbits after 6 weeks of corneal cross-linking in half of the eyes, while the other acted as control group. Clinical and corneal histopathological examination was done to evaluate the extent of inflammation, ulceration, organism penetration, and depth of corneal stromal affection. RESULTS The control eyes developed severe inflammation compared to the cross-linked eyes. Corneal melting occurred in 6 eyes in the control versus none in cross-linked group. Histopathological examination showed that the inflammation was confined to the superficial part of the stroma with localization of the inflammation in the cross-linked eyes in contrast to the control eyes that showed deep infiltration. CONCLUSION PACK-CXL provides infection localization through increasing the corneal rigidity and resistance to enzymatic digestion, even in the absence of the riboflavin microbicidal role. So, early PACK-CXL is worth to be considered in the IK treatment algorithm.
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Nissen EJ, Saeger M, Nölle B, Roider J. Clinicopathological Correlation of Microbial Keratitis and Ahead: Is There a Corneal Sepsis? Klin Monbl Augenheilkd 2022; 239:857-866. [PMID: 35858596 DOI: 10.1055/a-1811-7171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Microbial, infectious keratitis is a relevant indication for penetrating keratoplasty. The requirement for transplantation results in histopathological examination of the entire thickness of the cornea. Although the clinical diagnosis is not always possible to confirm, pathology can support diagnostic evidence of clinical presentation and pathogenesis. This is achieved with multiple methods from cytology, histochemistry, immunohistology, molecular pathology and in rare cases electron microscopy. These allow tissue-based detection of previous and parallel diseases and the responsible pathogens. The failure of satisfactory clinicopathological correlation raises the question whether a suspected pathogen was not ultimately responsible for destroyed corneal tissue. The pathogenesis of keratitis requiring transplantation is not yet completely understood, also on the experimental level. The development of such a keratitis can lead to a clinical symptomatology which can be described as "threatening organ dysfunction", a term used in sepsis research. Considering recent literature, possible correlations between sepsis and microbial keratitis and their relation to histopathology are discussed.
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Affiliation(s)
- Ebba J Nissen
- Klinik für Ophthalmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Deutschland
| | - Mark Saeger
- Klinik für Ophthalmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Deutschland
| | - Bernhard Nölle
- Klinik für Ophthalmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Deutschland
| | - Johann Roider
- Klinik für Ophthalmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Deutschland
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Majumdar R, Hariharan K, Vaishnavi S, Sugumar S. Review on Stenotrophomonas maltophilia: an emerging multidrug-resistant opportunistic pathogen. Recent Pat Biotechnol 2022; 16:329-354. [PMID: 35549857 DOI: 10.2174/1872208316666220512121205] [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: 08/31/2021] [Revised: 12/10/2021] [Accepted: 12/23/2021] [Indexed: 11/22/2022]
Abstract
Stenotrophomonas maltophilia is an opportunistic pathogen that results in nosocomial infections in immunocompromised individuals. These bacteria colonize on the surface of medical devices and therapeutic equipment like urinary catheters, endoscopes, and ventilators, causing respiratory and urinary tract infections. The low outer membrane permeability of multidrug-resistance efflux systems and the two chromosomally encoded β-lactamases present in S.maltophilia are challenging for arsenal control. The cell-associated and extracellular virulence factors in S.maltophilia are involved in colonization and biofilm formation on the host surfaces. The spread of antibiotic-resistant genes in the pathogenic S.maltophilia attributes to bacterial resistance against a wide range of antibiotics, including penicillin, quinolones, and carbapenems. So far, tetracycline derivatives, fluoroquinolones, and trimethoprim-sulfamethoxazole (TMP-SMX) are considered promising antibiotics against S.maltophilia. Due to the adaptive nature of the intrinsically resistant mechanism towards the number of antibiotics and its ability to acquire new resistance via mutation and horizontal gene transfer, it is quite tricky for medicinal contribution against S.maltophilia. The current review summarizes the literary data of pathogenicity, quorum sensing, biofilm formation, virulence factors, and antibiotic resistance of S.maltophilia.
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Affiliation(s)
- Rikhia Majumdar
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - K Hariharan
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - S Vaishnavi
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - Shobana Sugumar
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
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CrkII/Abl phosphorylation cascade is critical for NLRC4 inflammasome activity and is blocked by Pseudomonas aeruginosa ExoT. Nat Commun 2022; 13:1295. [PMID: 35277504 PMCID: PMC8917168 DOI: 10.1038/s41467-022-28967-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/22/2022] [Indexed: 11/17/2022] Open
Abstract
Type 3 Secretion System (T3SS) is a highly conserved virulence structure that plays an essential role in the pathogenesis of many Gram-negative pathogenic bacteria, including Pseudomonas aeruginosa. Exotoxin T (ExoT) is the only T3SS effector protein that is expressed in all T3SS-expressing P. aeruginosa strains. Here we show that T3SS recognition leads to a rapid phosphorylation cascade involving Abl / PKCδ / NLRC4, which results in NLRC4 inflammasome activation, culminating in inflammatory responses that limit P. aeruginosa infection in wounds. We further show that ExoT functions as the main anti-inflammatory agent for P. aeruginosa in that it blocks the phosphorylation cascade through Abl / PKCδ / NLRC4 by targeting CrkII, which we further demonstrate to be important for Abl transactivation and NLRC4 inflammasome activation in response to T3SS and P. aeruginosa infection. Pseudomonas aeruginosa secretes the toxin ExoT, which is important for pathogenesis. Here, the authors show that ExoT inhibits NLRC4-dependent inflammatory responses during wound infection.
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Ali M, Gu T, Yu X, Bashir A, Wang Z, Sun X, Ashraf NM, Li L. Identification of the Genes of the Plant Pathogen Pseudomonas syringae MB03 Required for the Nematicidal Activity Against Caenorhabditis elegans Through an Integrated Approach. Front Microbiol 2022; 13:826962. [PMID: 35356513 PMCID: PMC8959697 DOI: 10.3389/fmicb.2022.826962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/11/2022] [Indexed: 01/04/2023] Open
Abstract
Nematicidal potential of the common plant pathogen Pseudomonas syringae has been recently identified against Caenorhabditis elegans. The current study was designed to investigate the detailed genetic mechanism of the bacterial pathogenicity by applying comparative genomics, transcriptomics, mutant library screening, and protein expression. Results showed that P. syringae strain MB03 could kill C. elegans in the liquid assay by gut colonization. The genome of P. syringae MB03 was sequenced and comparative analysis including multi locus sequence typing, and genome-to-genome distance placed MB03 in phylogroup II of P. syringae. Furthermore, comparative genomics of MB03 with nematicidal strains of Pseudomonas aeruginosa (PAO1 and PA14) predicted 115 potential virulence factors in MB03. However, genes for previously reported nematicidal metabolites, such as phenazine, pyochelin, and pyrrolnitrin, were found absent in the MB03 genome. Transcriptomics analysis showed that the growth phase of the pathogen considerably affected the expression of virulence factors, as genes for the flagellum, glutamate ABC transporter, phoP/phoQ, fleS/fleR, type VI secretion system, and serralysin were highly up-regulated when stationary phase MB03 cells interacted with C. elegans. Additionally, screening of a transposon insertion mutant library led to the identification of other nematicidal genes such as acnA, gltP, oprD, and zapE. Finally, the nematicidal activity of selected proteins was confirmed by heterologous expression in Escherichia coli.
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Affiliation(s)
- Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad, Pakistan
| | - Tong Gu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xun Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Anum Bashir
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zhiyong Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaowen Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Naeem Mahmood Ashraf
- Department of Biochemistry and Biotechnology, University of Gujrat, Gujrat, Pakistan
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- *Correspondence: Lin Li,
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Radhakrishnan N, Prajna VN, Prajna LS, Venugopal A, Narayana S, Rajaraman R, Amescua G, Porco TC, Lietman TM, Rose-Nussbaumer J. Double-masked, sham and placebo-controlled trial of corneal cross-linking and topical difluprednate in the treatment of bacterial keratitis: Steroids and Cross-linking for Ulcer Treatment Trial (SCUT II) study protocol. BMJ Open Ophthalmol 2021; 6:e000811. [PMID: 34901464 PMCID: PMC8634009 DOI: 10.1136/bmjophth-2021-000811] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 10/28/2021] [Indexed: 11/15/2022] Open
Abstract
Introduction Although antibiotics are successful at achieving microbiological cure in infectious keratitis, outcomes are often poor due to corneal scarring. Ideal treatment of corneal ulcers would address both the infection and the inflammation. Adjunctive topical steroid treatment may improve outcomes by reducing inflammation. Corneal cross-linking (CXL) is a novel prospective therapy that may simultaneously reduce both inflammatory cells and bacterial pathogens. The purpose of this study is to determine differences in 6-month visual acuity between standard medical therapy with antibiotics versus antibiotics with adjunctive early topical steroid therapy versus antibiotic treatment plus CXL and early topical steroids. Methods and analysis This international, randomised, sham and placebo-controlled, three-arm clinical trial randomises patients with smear positive bacterial ulcers in a 1:1:1 fashion to one of three treatment arms: (1) topical 0.5% moxifloxacin plus topical placebo plus sham CXL; (2) topical 0.5% moxifloxacin plus difluprednate 0.05% plus sham CXL; or (3) the CXL group: topical 0.5% moxifloxacin plus difluprednate 0.05% plus CXL. Ethics and dissemination We anticipate that both adjunctive topical steroids and CXL will improved best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings and journal publications. Our data will also be available on reasonable request. Trial registration number NCT04097730.
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Affiliation(s)
| | | | | | | | | | | | - Guillermo Amescua
- Dept of Ophthalmology, University of Miami Health System Bascom Palmer Eye Institute, Miami, Florida, USA
| | - Travis C Porco
- FI Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
| | - Thomas M Lietman
- Dept of Ophthalmology, University of California, San Francisco, California, USA
| | - Jennifer Rose-Nussbaumer
- FI Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
- Ophthalmology, University of California, San Francisco, San Francisco, California, USA
- Byers Eye Institute, Dept of Ophthalmology, Stanford University, California, San Francisco, USA
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Romanowski EG, Yadav S, Stella NA, Yates KA, Romanowski JE, Dhaliwal DK, Shanks RMQ. Bacterial Keratitis: Similar Bacterial and Clinical Outcomes in Female versus Male New Zealand White Rabbits Infected with Serratia marcescens. Curr Eye Res 2021; 47:505-510. [PMID: 34854780 DOI: 10.1080/02713683.2021.2013897] [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: 10/19/2022]
Abstract
PURPOSE Females and males respond differently to a number of systemic viral infections. Differences between females and males with respect to the severity of keratitis caused by Gram-negative bacteria such as Serratia marcescens are less well established. METHODS In this study, we injected female and male New Zealand White rabbit corneas with a keratitis isolate of S. marcescens and evaluated the eyes after 48 hours for a number of clinical and microbiological parameters. RESULTS No statistical differences in bacterial burden and corneal scores were recorded between female and male rabbits although there was a non-significant trend toward a higher frequency of female rabbits demonstrating hypopyons. CONCLUSIONS This data suggests that for experimental bacterial keratitis studies involving Gram-negative rods, a single sex or mixed group of rabbit is sufficient for evaluating pathology and bacterial burdens. This will reduce the number of animals used for subsequent studies.
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Affiliation(s)
- Eric G Romanowski
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sanya Yadav
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nicholas A Stella
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kathleen A Yates
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - John E Romanowski
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Deepinder K Dhaliwal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robert M Q Shanks
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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13
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Duplantier M, Lohou E, Sonnet P. Quorum Sensing Inhibitors to Quench P. aeruginosa Pathogenicity. Pharmaceuticals (Basel) 2021; 14:1262. [PMID: 34959667 PMCID: PMC8707152 DOI: 10.3390/ph14121262] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/22/2022] Open
Abstract
The emergence and the dissemination of multidrug-resistant bacteria constitute a major public health issue. Among incriminated Gram-negative bacteria, Pseudomonas aeruginosa has been designated by the WHO as a critical priority threat. During the infection process, this pathogen secretes various virulence factors in order to adhere and colonize host tissues. Furthermore, P. aeruginosa has the capacity to establish biofilms that reinforce its virulence and intrinsic drug resistance. The regulation of biofilm and virulence factor production of this micro-organism is controlled by a specific bacterial communication system named Quorum Sensing (QS). The development of anti-virulence agents targeting QS that could attenuate P. aeruginosa pathogenicity without affecting its growth seems to be a promising new therapeutic strategy. This could prevent the selective pressure put on bacteria by the conventional antibiotics that cause their death and promote resistant strain survival. This review describes the QS-controlled pathogenicity of P. aeruginosa and its different specific QS molecular pathways, as well as the recent advances in the development of innovative QS-quenching anti-virulence agents to fight anti-bioresistance.
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Affiliation(s)
| | | | - Pascal Sonnet
- AGIR, UR4294, UFR of Pharmacy, Jules Verne University of Picardie, 80037 Amiens, France; (M.D.); (E.L.)
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14
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Genomic and Metabolic Characteristics of the Pathogenicity in Pseudomonas aeruginosa. Int J Mol Sci 2021; 22:ijms222312892. [PMID: 34884697 PMCID: PMC8657582 DOI: 10.3390/ijms222312892] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 01/22/2023] Open
Abstract
In recent years, the effectiveness of antimicrobials in the treatment of Pseudomonas aeruginosa infections has gradually decreased. This pathogen can be observed in several clinical cases, such as pneumonia, urinary tract infections, sepsis, in immunocompromised hosts, such as neutropenic cancer, burns, and AIDS patients. Furthermore, Pseudomonas aeruginosa causes diseases in both livestock and pets. The highly flexible and versatile genome of P. aeruginosa allows it to have a high rate of pathogenicity. The numerous secreted virulence factors, resulting from its numerous secretion systems, the multi-resistance to different classes of antibiotics, and the ability to produce biofilms are pathogenicity factors that cause numerous problems in the fight against P. aeruginosa infections and that must be better understood for an effective treatment. Infections by P. aeruginosa represent, therefore, a major health problem and, as resistance genes can be disseminated between the microbiotas associated with humans, animals, and the environment, this issue needs be addressed on the basis of an One Health approach. This review intends to bring together and describe in detail the molecular and metabolic pathways in P. aeruginosa's pathogenesis, to contribute for the development of a more targeted therapy against this pathogen.
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15
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Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2021; 88:101028. [PMID: 34813978 DOI: 10.1016/j.preteyeres.2021.101028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
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Affiliation(s)
- Rohan Bir Singh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Leiden University Medical Center, 2333, ZA Leiden, the Netherlands
| | - Sujata Das
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Bhubaneshwar, India
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Michael E Zegans
- Department of Ophthalmology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Regis P Kowalski
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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Castro-Saines E, Hernandez-Ortiz R, Lagunes-Quintanilla R, Peña-Chora G. Characterization of a strain of Serratia sp. with ixodicide activity against the cattle tick Rhipicephalus microplus. EXPERIMENTAL & APPLIED ACAROLOGY 2021; 85:101-111. [PMID: 34559350 DOI: 10.1007/s10493-021-00640-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Cattle ticks are considered the most important ectoparasite in the livestock industry. Rhipicephalus microplus causes economic losses both through direct feeding on livestock and through disease transmission. Reports of the failure of chemical ixodicides to control this tick have led to a search for control alternatives, such as bacteria with ixodicide activity. The objective of this work was to select a bacterial strain with ixodicide activity against R. microplus. In total, 83 bacterial strains were isolated from soil and dead R. microplus specimens, and all strains were evaluated against larvae in a screening test. Bacteria with ixodicide activity were evaluated in larvae and engorged adult female ticks. The larvae were challenged using the larval immersion test (LIT) with 20 µg/mL total protein. The median lethal concentration (LC50) for larvae was obtained by using nine total protein concentrations. Engorged adult female ticks were challenged using the adult immersion test (AIT) with six protein concentrations. We evaluated adult mortality on day 10, oviposition rate on day 14 and hatching rate on day 40 after challenge. Only one bacterial strain (EC-35) showed ixodicide activity against larvae and adult R. microplus. The highest larval mortality, 52.3%, occurred with a total protein concentration of 40 μg/mL, and the LC50 was 13.9 µg/mL of protein. In adults, a total protein concentration of 10 µg/mL had the highest mortality (55%), oviposition inhibition (50.9%) and reproductive potential inhibition (52.5%). However, there was no significant effect on hatching. The 16S rRNA gene sequence showed 99% identity of EC-35 with Serratia sp.
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Affiliation(s)
- Edgar Castro-Saines
- Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Avenida Universidad, 1001, Colonia Chamilpa, CP 62209, Cuernavaca, Morelos, Mexico
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Carretera Federal Cuernavaca-Cuautla 8534, Colonia Progreso, CP 62550, Jiutepec, Morelos, Mexico
| | - Ruben Hernandez-Ortiz
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Carretera Federal Cuernavaca-Cuautla 8534, Colonia Progreso, CP 62550, Jiutepec, Morelos, Mexico
| | - Rodolfo Lagunes-Quintanilla
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Carretera Federal Cuernavaca-Cuautla 8534, Colonia Progreso, CP 62550, Jiutepec, Morelos, Mexico
| | - Guadalupe Peña-Chora
- Centro de Investigaciones Biológicas, Universidad Autónoma del Estado de Morelos, Avenida Universidad, 1001, Colonia Chamilpa, CP 62209, Cuernavaca, Morelos, Mexico.
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17
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Zhu Y, Ge X, Xie D, Wang S, Chen F, Pan S. Clinical Strains of Pseudomonas aeruginosa Secrete LasB Elastase to Induce Hemorrhagic Diffuse Alveolar Damage in Mice. J Inflamm Res 2021; 14:3767-3780. [PMID: 34393497 PMCID: PMC8354736 DOI: 10.2147/jir.s322960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/28/2021] [Indexed: 12/12/2022] Open
Abstract
Background Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) are most often caused by bacterial pneumonia and characterized by severe dyspnea and high mortality. Knowledge about the lung injury effects of current clinical bacterial strains is lacking. The aim of this study was to investigate the ability of representative pathogenic bacteria isolated from patients to cause ALI/ARDS in mice and identify the major virulence factor. Methods Seven major bacterial species were isolated from clinical sputum and unilaterally instilled into the mouse airway. A histology study was performed to determine the lung injury effect. Virulence genes were examined by PCR. Sequence types of P. aeruginosa strains were identified by MLST. LC-MS/MS was used to analysis the bacterial exoproducts proteome. LasB was purified through a DEAE-cellulose column, and its toxicity was tested both in vitro and in vivo. Results Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus agalactiae, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli were randomly separated and tested 3 times. Among them, gram-negative bacteria have much more potential to cause acute lung injury than gram-positive bacteria. However, P. aeruginosa is the only pathogen that induces diffuse alveolar damage, hemorrhage and hyaline membranes in the lungs of mice. The lung injury effect is associated with the excreted LasB elastase. Purified LasB recapitulated lung injury similar to P. aeruginosa infection in vivo. We found that this was due to the powerful degradation effect of LasB on the extracellular matrix of the lung and key proteins in the coagulation cascade without inducing obvious cellular apoptosis. We also report for the first time that LasB could induce DIC-like coagulopathy in vitro. Conclusion P. aeruginosa strains are most capable of inducing ALI/ARDS in mice among major clinical pathogenic bacteria tested, and this ability is specifically attributed to their LasB production.
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Affiliation(s)
- Yajie Zhu
- Department of Emergency Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Xiaoli Ge
- Department of Emergency Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Di Xie
- Department of Emergency Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Shangyuan Wang
- Department of Emergency Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Feng Chen
- Division of Medical Microbiology, Department of Clinical Laboratory, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
| | - Shuming Pan
- Department of Emergency Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, People's Republic of China
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18
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Atta S, Perera C, Nayyar S, Kowalski RP, Jhanji V. An 18-Year Overview of Serratia marcescens Ocular Infection. Eye Contact Lens 2021; 47:471-475. [PMID: 34050088 DOI: 10.1097/icl.0000000000000803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE Serratia marcescens is a frequent ocular bacterial pathogen implicated in keratitis, endophthalmitis, and conjunctivitis. We evaluated the risk factors and treatment outcomes of ocular infections due to S. marcescens. METHODS In this retrospective observational study, all S. marcescens-positive cases between February 2002 and February 2020 were reviewed for ocular risk factors that included log of minimal angle of resolution visual acuity (VA), medical management, and time to epithelial defect closure. RESULTS Fifty-one patients were identified (72.5% females, 46.8±23.3 years). Forty-six patients had complete medical records, and 5 had microbiology data available. The most prevalent ocular risk factors were, contact lens (CL) use (68.6%), corneal disease (52.9%), and history of ocular surgery (41.2%). Mean presenting VA was 1.3±1.0. About half of the patients presented with a central ulcer (49%, 25), large infiltrate (20.4±31.8 mm2 mean), and hypopyon (43.1%, 22). All cases were reported to be susceptible to ciprofloxacin. Defect closure occurred in 52.3±117.1 days and final VA was 0.86±0.88. Adjunctive treatments were required in 14 cases (27.5%). One patient underwent surgical intervention. Features associated with poor VA outcomes included, history of glaucoma (P=0.038), older age at presentation (P<0.001), presence of hypopyon (0.045), poor VA at presentation (0.0086), time to epithelial defect closure (0.0196), and large infiltrate size (P=0.0345). CONCLUSIONS S. marcescens keratitis and conjunctivitis is associated with CL use and history of ocular surface disease. Worse outcomes were associated with older age, infiltrate size, presence of hypopyon, worse initial VA, longer time to epithelial defect closure, and history of glaucoma.
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Affiliation(s)
- Sarah Atta
- Department of Ophthalmology (S.A., R.P.K., V.J.), University of Pittsburgh School of Medicine, Pittsburgh, PA; Department of Ophthalmology (C.P.), Stanford University School of Medicine, Stanford, CA; and The Charles T. Campbell Ophthalmic Microbiology Laboratory (S.N., R.P.K., V.J.), University of Pittsburgh Medical Center, Pittsburgh, PA
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19
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Rahman F, Nguyen TM, Adekoya OA, Campestre C, Tortorella P, Sylte I, Winberg JO. Inhibition of bacterial and human zinc-metalloproteases by bisphosphonate- and catechol-containing compounds. J Enzyme Inhib Med Chem 2021; 36:819-830. [PMID: 33757387 PMCID: PMC7993378 DOI: 10.1080/14756366.2021.1901088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Compounds containg catechol or bisphosphonate were tested as inhibitors of the zinc metalloproteases, thermolysin (TLN), pseudolysin (PLN) and aureolysin (ALN) which are bacterial virulence factors, and the human matrix metalloproteases MMP-9 and -14. Inhibition of virulence is a putative strategy in the development of antibacterial drugs, but the inhibitors should not interfere with human enzymes. Docking indicated that the inhibitors bound MMP-9 and MMP-14 with the phenyl, biphenyl, chlorophenyl, nitrophenyl or methoxyphenyl ringsystem in the S1'-subpocket, while these ringsystems entered the S2'- or S1 -subpockets or a region involving amino acids in the S1'- and S2'-subpockets of the bacterial enzymes. An arginine conserved among the bacterial enzymes seemed to hinder entrance deeply into the S1'-subpocket. Only the bisphosphonate containing compound RC2 bound stronger to PLN and TLN than to MMP-9 and MMP-14. Docking indicated that the reason was that the conserved arginine (R203 in TLN and R198 in PLN) interacts with phosphate groups of RC2.
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Affiliation(s)
- Fatema Rahman
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Tra-Mi Nguyen
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Olayiwola A Adekoya
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Cristina Campestre
- Department of Pharmacy, University of "G. d'Annunzio" Chieti, Chieti, Italy
| | - Paolo Tortorella
- Department of Pharmacy, Science of Pharmacy, University "A. Moro" Bari, Bari, Italy
| | - Ingebrigt Sylte
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Jan-Olof Winberg
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
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20
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Figueroa J, Villagrán D, Cartes C, Solis C, Nourdin-Galindo G, Haussmann D. Analysis of genes encoding for proteolytic enzymes and cytotoxic proteins as virulence factors of Piscirickettsia salmonis in SHK-1 cells. JOURNAL OF FISH DISEASES 2021; 44:495-504. [PMID: 33455005 DOI: 10.1111/jfd.13333] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/24/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Piscirickettsia salmonis is the causative agent of Piscirickettsiosis, a systemic disease generating high mortality rates in farmed salmon cultures of southern Chile. Proteolytic enzymes are important virulence factors since they play a key role in bacterial invasion and proliferation within the host. Bacteria growing in muscle tissues are known to secrete proteases, but no proteolytic enzymes have been described in P. salmonis to date. A battery of putative protease genes was found in the genomes and available strains of P. salmonis by bioinformatics analyses, and their identity was established through comparison with protease genes in databases. The transcript levels of five candidate genes were analysed by in vitro infection and qPCR. All strains were found to generate protease activity to varying degrees, and this was significantly increased when bacteria infected a salmon cell line. Gene expression of several types of proteases was also evidenced, with the highest levels corresponding to the type 1 secretion system (T1SS), which is also involved in the transport of haemolysin A, although transcripts with significant levels of peptidase M4 (thermolysin) and CLP protease were also found.
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Affiliation(s)
- Jaime Figueroa
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Daniela Villagrán
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Carlos Cartes
- Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile
| | - Camila Solis
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | - Denise Haussmann
- Departmento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Valdivia, Chile
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Tsvetanova A, Powell RM, Tsvetanov KA, Smith KM, Gould DJ. Melting corneal ulcers (keratomalacia) in dogs: A 5-year clinical and microbiological study (2014-2018). Vet Ophthalmol 2021; 24:265-278. [PMID: 33794048 DOI: 10.1111/vop.12885] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To identify bacterial microorganisms associated with canine keratomalacia, review their antimicrobial sensitivity, and evaluate clinical outcomes compared to results of microbial culture. METHODS Retrospective analysis of clinical records of dogs diagnosed with a melting corneal ulcer presented to a referral hospital in Hertfordshire, UK between 2014 and 2018. RESULTS One hundred and ten melting corneal ulcers were sampled in 106 dogs. The most common pure bacterial isolate was Pseudomonas aeruginosa (n = 26) followed by β-hemolytic Streptococcus (n = 12). Melting corneal ulcers that cultured coagulase-positive Staphylococcus, coliform bacteria, Pasteurella multocida, Enterococcus, and Streptococcus viridans presented in smaller numbers and were analyzed together (n = 16). Multiple cultures were identified in nine cases (n = 9). Forty-seven cultures yielded no bacterial growth (n = 47). The susceptibility to fluoroquinolones remained high with the exception of β-hemolytic Streptococci. There was no significant difference in the ulcer severity at presentation in regard to the cultured bacteria. Overall, 63 eyes (57%) received surgical grafting in addition to medical treatment. In 14 cases (13%), the progression of corneal melting despite medical ± surgical treatment resulted in enucleation. Fifty-seven percent (8/14) of the enucleated eyes cultured pure Pseudomonas aeruginosa isolates. In contrast, all β-hemolytic Streptococcus-associated ulcers healed. CONCLUSIONS The most common bacterial species associated with canine keratomalacia were Pseudomonas aeruginosa and β-hemolytic Streptococcus. Because of the variation in antibacterial sensitivity between these two species, bacterial culture and sensitivity testing should be performed in all dogs presenting with keratomalacia. Melting corneal ulcers associated with pure Pseudomonas infection were significantly more likely to result in globe loss than melting corneal ulcers associated with other cultures.
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Affiliation(s)
- Agata Tsvetanova
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
| | | | - Kamen A Tsvetanov
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Kerry M Smith
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
| | - David J Gould
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
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22
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Jing C, Liu C, Liu Y, Feng R, Cao R, Guan Z, Xuan B, Gao Y, Wang Q, Yang N, Ma Y, Lan L, Feng J, Shen B, Wang H, Yu Y, Yang G. Antibodies Against Pseudomonas aeruginosa Alkaline Protease Directly Enhance Disruption of Neutrophil Extracellular Traps Mediated by This Enzyme. Front Immunol 2021; 12:654649. [PMID: 33868297 PMCID: PMC8044376 DOI: 10.3389/fimmu.2021.654649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/17/2021] [Indexed: 12/20/2022] Open
Abstract
Extracellular traps released by neutrophils (NETs) are essential for the clearance of Pseudomonas aeruginosa. Alkaline protease (AprA) secreted by P. aeruginosa negatively correlates with clinical improvement. Moreover, anti-AprA in patients with cystic fibrosis (CF) can help identify patients with aggressive forms of chronic infection. However, the mechanism underlying the clinical outcomes remains unclear. We demonstrated that aprA deficiency in P. aeruginosa decreased the bacterial burden and reduced lung infection. AprA degraded NET components in vitro and in vivo but did not affect NET formation. Importantly, antibodies induced by AprA acted as an agonist and directly enhanced the degrading activities of AprA. Moreover, antisera from patients with P. aeruginosa infection exhibited antibody-dependent enhancement (ADE) similar to that of the antibodies we prepared. Our further investigations showed that the interaction between AprA and the specific antibodies might make the enzyme active sites better exposed, and subsequently enhance the recognition of substrates and accelerate the degradation. Our findings revealed that AprA secreted by P. aeruginosa may aggravate infection by destroying formed NETs, an effect that was further enhanced by its antibodies.
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Affiliation(s)
- Chendi Jing
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China.,Department of Infectious Diseases, Peking University First Hospital, Beijing, China
| | - Chenghua Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Yu Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Ruli Feng
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Run Cao
- Joint National Laboratory for Antibody Drug Engineering, School of Basic Medical Sciences, Henan University, Kaifeng, China
| | - Zhangchun Guan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Bo Xuan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Yaping Gao
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Qi Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Nana Yang
- Department of Molecular Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yuanfang Ma
- Joint National Laboratory for Antibody Drug Engineering, School of Basic Medical Sciences, Henan University, Kaifeng, China
| | - Lefu Lan
- Department of Molecular Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jiannan Feng
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Beifen Shen
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Yanyan Yu
- Department of Infectious Diseases, Peking University First Hospital, Beijing, China
| | - Guang Yang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing, China
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Cross-Linking Assisted Infection Reduction (CLAIR): A Randomized Clinical Trial Evaluating the Effect of Adjuvant Cross-Linking on Bacterial Keratitis. Cornea 2020; 40:837-841. [PMID: 33079921 DOI: 10.1097/ico.0000000000002510] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/20/2020] [Indexed: 01/10/2023]
Abstract
PURPOSE To determine whether there is a benefit to adjuvant corneal cross-linking (CXL) for bacterial keratitis. METHODS This is an outcome-masked, randomized controlled clinical trial. Consecutive patients presenting with a smear-positive bacterial ulcer at Aravind Eye Hospitals at Madurai, Pondicherry, and Coimbatore in India were enrolled. Study eyes were randomized to topical moxifloxacin 0.5% or topical moxifloxacin 0.5% plus CXL. The primary outcome of the trial was microbiological cure at 24 hours on repeat culture. Secondary outcomes included best spectacle corrected visual acuity at 3 weeks and 3 months, percentage of study participants with epithelial healing at 3 weeks and 3 months, infiltrate and/or scar size at 3 weeks and 3 months, 3-day smear and culture, and adverse events. RESULTS Those randomized to CXL had 0.60 decreased odds of culture positivity at 24 hours (95% confidence interval [CI]: 0.10-3.50; P = 0.65), 0.9 logarithm of the minimum angle of resolution lines worse visual acuity (95% CI: -2.8 to 4.6; P = 0.63), and 0.41-mm larger scar size (95% CI: -0.48 to 1.30; P = 0.38) at 3 months. We note fewer corneal perforations or need for therapeutic penetrating keratoplasty in the CXL group. CONCLUSIONS We were unable to confirm a benefit to adjuvant CXL in the primary treatment of moderate bacterial keratitis. However, CXL may reduce culture positivity and complication rates; therefore, a larger trial to fully evaluate this is warranted. TRIAL REGISTRATION NCT02570321.
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Rodrigues YC, Furlaneto IP, Maciel AHP, Quaresma AJPG, de Matos ECO, Conceição ML, Vieira MCDS, Brabo GLDC, Sarges EDSNF, Lima LNGC, Lima KVB. High prevalence of atypical virulotype and genetically diverse background among Pseudomonas aeruginosa isolates from a referral hospital in the Brazilian Amazon. PLoS One 2020; 15:e0238741. [PMID: 32911510 PMCID: PMC7482967 DOI: 10.1371/journal.pone.0238741] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/21/2020] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen causing different types of infections, particularly in intensive care unit patients. Characteristics that favor its persistence artificial environments are related to its high adaptability, wide arsenal of virulence factors and resistance to several antimicrobial classes. Among the several virulence determinants, T3SS stands as the most important due to the clinical impact of exoS and exoU genes in patient’s outcome. The molecular characterization of P. aeruginosa isolates helps in the comprehension of transmission dynamics and enhance knowledge of virulence and resistance roles in infection process. In the present study, we investigated virulence and resistance properties and the genetic background of P. aeruginosa isolated from ICUs patients at a referral hospital in Brazilian Amazon. A total of 54 P. aeruginosa isolates were characterized by detecting 19 virulence-related genes, antimicrobial susceptibility testing, molecular detection of β-lactamase-encoding genes and genotyping by MLST and rep-PCR. Our findings showed high prevalence of virulence-related markers, where 53.7% of the isolates presented at least 17 genes among the 19 investigated (P = 0.01). The rare exoS+/exoU+ cytotoxic virulotype was detected in 55.6% of isolates. Antimicrobial susceptibility testing revealed percentages of antibiotic resistance above 50% to carbapenems, cephalosporins and fluoroquinolones associated to MDR/XDR isolates. Isolates harboring both blaSPM-1 and blaOXA genes were also detected. Genotyping methods demonstrated a wide genetic diversity of strains spread among the different intensive care units, circulation of international MDR/XDR high-risk clones (ST111, ST235, ST244 and ST277) and emergence of seven novel MLST lineages. Finally, our findings highlight the circulation of strains with high virulence potential and resistance to antimicrobials and may be useful on comprehension of pathogenicity process, treatment guidance and establishment of strategies to control the spread of epidemic P. aeruginosa strains.
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Affiliation(s)
- Yan Corrêa Rodrigues
- Programa de Pós-graduação em Biologia Parasitária na Amazônia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará (UEPA), Belém, Pará, Brazil
- * E-mail: (YCR); (KVBL)
| | - Ismari Perini Furlaneto
- Programa de Pós-graduação em Educação em Saúde, Centro Universitário do Pará (CESUPA), Belém, Pará Brazil
| | - Arthur Henrique Pinto Maciel
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
| | - Ana Judith Pires Garcia Quaresma
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
| | - Eliseth Costa Oliveira de Matos
- Departamento de Patologia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará (UEPA), Belém, Pará, Brazil
| | - Marília Lima Conceição
- Programa de Pós-graduação em Biologia Parasitária na Amazônia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará (UEPA), Belém, Pará, Brazil
| | - Marcelo Cleyton da Silva Vieira
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
| | - Giulia Leão da Cunha Brabo
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
| | | | - Luana Nepomuceno Godim Costa Lima
- Programa de Pós-graduação em Biologia Parasitária na Amazônia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará (UEPA), Belém, Pará, Brazil
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
| | - Karla Valéria Batista Lima
- Programa de Pós-graduação em Biologia Parasitária na Amazônia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará (UEPA), Belém, Pará, Brazil
- Laboratório de Biologia Molecular, Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ministério da Saúde, Ananindeua, Pará, Brazil
- * E-mail: (YCR); (KVBL)
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Dissecting capture and twisting of aureolysin and pseudolysin: functional amino acids of the Dispase autolysis-inducing protein. Biochem J 2020; 477:2595-2606. [PMID: 32602533 DOI: 10.1042/bcj20200407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 11/17/2022]
Abstract
The Dispase autolysis-inducing protein (DAIP) from Streptomyces mobaraensis attracts M4 metalloproteases, which results in inhibition and autolysis of bacillolysin (BL) and thermolysin (TL). The present study shows that aureolysin (AL) from Staphylococcus aureus and pseudolysin (LasB) from Pseudomonas aeruginosa are likewise impaired by DAIP. Complete inhibition occurred when DAIP significantly exceeded the amount of the target protease. At low DAIP concentrations, AL and BL performed autolysis, while LasB and TL degradation required reductants or detergents that break intramolecular disulfide bonds or change the protein structure. Site directed mutagenesis of DAIP and removal of an exposed protein loop either influenced binding or inhibition of AL and TL but had no effect on LasB and BL. The Y170A and Δ239-248 variants had completely lost affinity for TL and AL. The exchange of Asn-275 also impaired the interaction of DAIP with AL. In contrast, DAIP Phe-297 substitution abolished inhibition and autolysis of both target proteases but still allowed complex formation. Our results give rise to the conclusion that other, yet unknown DAIP amino acids inactivate LasB and BL. Obviously, various bacteria in the same habitat caused Streptomyces mobaraensis to continuously optimize DAIP in inactivating the tackling metalloproteases.
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M Campos JC, Antunes LCM, Ferreira RBR. Global priority pathogens: virulence, antimicrobial resistance and prospective treatment options. Future Microbiol 2020; 15:649-677. [DOI: 10.2217/fmb-2019-0333] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Salmonella spp. are part of a group of pathogens that pose a major threat to human health due to the emergence of multidrug-resistant strains. Moreover, these bacteria have several virulence factors that allow them to successfully colonize their hosts, such as toxins and the ability to produce biofilms, resulting in an urgent need to develop new strategies to fight these pathogens. In this review, we compile the most up-to-date information on the epidemiology, virulence and resistance of these clinically important microorganisms. Additionally, we address new therapeutic alternatives, with a focus on molecules with antivirulence activity, which are considered promising to combat multidrug-resistant bacteria.
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Affiliation(s)
- Juliana C de M Campos
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis CM Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rosana BR Ferreira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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González GM, Andrade A, Villanueva-Lozano H, Campos-Cortés CL, Becerril-García MA, Montoya AM, Sánchez-González A, Bonifaz A, Franco-Cendejas R, López-Jácome LE, Treviño-Rangel RDJ. Comparative Analysis of Virulence Profiles of Serratia marcescens Isolated from Diverse Clinical Origins in Mexican Patients. Surg Infect (Larchmt) 2020; 21:608-612. [PMID: 32326831 DOI: 10.1089/sur.2020.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Serratia marcescens is an enteric bacterium with increasing incidence in clinical settings, attributed mainly to the opportune expression of diverse virulence determinants plus a wide intrinsic and acquired antibiotic resistance. Methods: The aim of this study was to compare the virulence factor profiles of 185 Serratia marcescens isolates from different clinical origins. In vitro proteolytic and hemolytic activities, biofilm formation, and motility were assessed in each strain. Additionally, the pathogenicity of four hypervirulent strains was analyzed in vivo in Galleria mellonella. Results: We found that bacterial isolates from wound/abscess and respiratory tract specimens exhibited the highest protease activity along with a strong biofilm production, while uropathogenic isolates showed the highest hemolytic activity. Swarming and swimming motilities were similar among all the strains. However, respiratory tract isolates showed the most efficient motility. Two hyperhemolytic and two hyperproteolytic strains were detected; the latter were more efficient killing Galleria mellonella with a 50%-60% larval mortality 48 hours after challenge. Conclusion: A correlation was found between biofilm formation and proteolytic and hemolytic activities in biopsy specimens and bloodstream isolates, respectively. Overall, it becomes critical to evaluate and compare the clinical strains virulence diversity in order to understand the underlying mechanisms that allow the establishment and persistence of opportunistic bacterial infections in the host.
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Affiliation(s)
- Gloria M González
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Angel Andrade
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Hiram Villanueva-Lozano
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Christian L Campos-Cortés
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Miguel A Becerril-García
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Alexandra M Montoya
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Alejandro Sánchez-González
- Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Alexandro Bonifaz
- Servicio de Dermatología y Departamento de Micología, Hospital General de México "Dr. Eduardo Liceaga," Mexico City, Mexico
| | - Rafael Franco-Cendejas
- Laboratorio de Infectología, Instituto Nacional de Rehabilitación "Luis Guillermo Ibarra Ibarra," Mexico City, Mexico
| | - Luis E López-Jácome
- Laboratorio de Infectología, Instituto Nacional de Rehabilitación "Luis Guillermo Ibarra Ibarra," Mexico City, Mexico
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Skaljac M, Vogel H, Wielsch N, Mihajlovic S, Vilcinskas A. Transmission of a Protease-Secreting Bacterial Symbiont Among Pea Aphids via Host Plants. Front Physiol 2019; 10:438. [PMID: 31057424 PMCID: PMC6479166 DOI: 10.3389/fphys.2019.00438] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/01/2019] [Indexed: 12/02/2022] Open
Abstract
Aphids are economically important pest insects that damage plants by phloem feeding and the transmission of plant viruses. Their ability to feed exclusively on nutritionally poor phloem sap is dependent on the obligatory symbiotic bacterium Buchnera aphidicola, but additional facultative symbionts may also be present, a common example of which is Serratia symbiotica. Many Serratia species secrete extracellular enzymes, so we hypothesised that S. symbiotica may produce proteases that help aphids to feed on plants. Molecular analysis, including fluorescence in situ hybridization (FISH), revealed that S. symbiotica colonises the gut, salivary glands and mouthparts (including the stylet) of the pea aphid Acyrthosiphon pisum, providing a mechanism to transfer the symbiont into host plants. S. symbiotica was also detected in plant tissues wounded by the penetrating stylet and was transferred to naïve aphids feeding on plants containing this symbiont. The maintenance of S. symbiotica by repeated transmission via plants may explain the high frequency of this symbiont in aphid populations. Proteomic analysis of the supernatant from a related but cultivable S. symbiotica strain cultured in liquid medium revealed the presence of known and novel proteases including metalloproteases. The corresponding transcripts encoding these S. symbiotica enzymes were detected in A. pisum and in plants carrying the symbiont, although the mRNA was much more abundant in the aphids. Our data suggest that enzymes from S. symbiotica may facilitate the digestion of plant proteins, thereby helping to suppress plant defense, and that the symbionts are important mediators of aphid–plant interactions.
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Affiliation(s)
- Marisa Skaljac
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Heiko Vogel
- Entomology Department, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Natalie Wielsch
- Entomology Department, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sanja Mihajlovic
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Andreas Vilcinskas
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany.,Institute for Insect Biotechnology, Justus-Liebig University of Giessen, Giessen, Germany
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Rosetta P, Legrottaglie EF, Pagano L, Vinciguerra P. Corneal Cross-Linking Window Absorption (CXL-WA) as an Adjuvant Therapy in the Management of Aspergillus niger Keratitis. Case Rep Ophthalmol Med 2018; 2018:4856019. [PMID: 30643657 PMCID: PMC6311300 DOI: 10.1155/2018/4856019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/19/2018] [Accepted: 11/22/2018] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To evaluate the effectiveness of corneal cross-linking window absorption (CXL-WA) as an adjuvant therapy for Aspergillus keratitis. METHODS A 90-year-old male came to our clinic complaining of hyperemic conjunctivitis and progressive visual loss in the right eye. Slit-lamp examination showed keratic precipitates, severe corneal opacity, and stromal edema. Corneal scraping culture was positive for Aspergillus niger. Because the clinical condition did not sufficiently improve with antifungal therapy, the patient underwent CXL-WA as an adjuvant therapy. RESULTS During the first week after treatment, the Tyndall effect, corneal edema, and signs of ocular inflammation progressively lessened. At the third postoperative month, the cornea was stable without signs of fungal keratitis. However, after this period, a descemetocele appeared in the cornea (2 × 2 mm in diameter), so the patient underwent a corneal penetrating keratoplasty. Histological evaluation of the removed corneal tissue revealed the presence of hyphae and fungal infection. CONCLUSIONS We reported a case of in vivo CXL-WA used as an adjuvant therapy for deep stromal Aspergillus keratitis. CXL did not completely eradicate the fungal infection which caused perforation 4 months after treatment and it still cannot be considered a definitive solution to mycotic keratitis, which maintains a poor long-term prognosis.
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Affiliation(s)
- Pietro Rosetta
- Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, Milano, Italy
| | | | - Luca Pagano
- Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, Milano, Italy
| | - Paolo Vinciguerra
- Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, Milano, Italy
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Buss CG, Dudani JS, Akana RTK, Fleming HE, Bhatia SN. Protease activity sensors noninvasively classify bacterial infections and antibiotic responses. EBioMedicine 2018; 38:248-256. [PMID: 30503861 PMCID: PMC6306379 DOI: 10.1016/j.ebiom.2018.11.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/08/2018] [Accepted: 11/15/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Respiratory tract infections represent a significant public health risk, and timely and accurate detection of bacterial infections facilitates rapid therapeutic intervention. Furthermore, monitoring the progression of infections after intervention enables 'course correction' in cases where initial treatments are ineffective, avoiding unnecessary drug dosing that can contribute to antibiotic resistance. However, current diagnostic and monitoring techniques rely on non-specific or slow readouts, such as radiographic imaging and sputum cultures, which fail to specifically identify bacterial infections and take several days to identify optimal antibiotic treatments. METHODS Here we describe a nanoparticle system that detects P. aeruginosa lung infections by sensing host and bacterial protease activity in vivo, and that delivers a urinary detection readout. One protease sensor is comprised of a peptide substrate for the P. aeruginosa protease LasA. A second sensor designed to detect elastases is responsive to recombinant neutrophil elastase and secreted proteases from bacterial strains. FINDINGS In mice infected with P. aeruginosa, nanoparticle formulations of these protease sensors-termed activity-based nanosensors (ABNs)-detect infections and monitor bacterial clearance from the lungs over time. Additionally, ABNs differentiate between appropriate and ineffective antibiotic treatments acutely, within hours after the initiation of therapy. INTERPRETATION These findings demonstrate how activity measurements of disease-associated proteases can provide a noninvasive window into the dynamic process of bacterial infection and resolution, offering an opportunity for detecting, monitoring, and characterizing lung infections. FUND: National Cancer Institute, National Institute of Environmental Health Sciences, National Institutes of Health, National Science Foundation Graduate Research Fellowship Program, and Howard Hughes Medical Institute.
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Affiliation(s)
- Colin G Buss
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Harvard-MIT Health Sciences and Technology Program, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jaideep S Dudani
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Reid T K Akana
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Heather E Fleming
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Harvard-MIT Health Sciences and Technology Program, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sangeeta N Bhatia
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Harvard-MIT Health Sciences and Technology Program, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA.
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Abstract
PURPOSE Pseudomonas aeruginosa produces pyoverdine, encoded by the pvdE gene, for high-affinity iron uptake from transferrin and lactoferrin. This study investigated the contribution of pyoverdine to P. aeruginosa keratitis pathogenesis using in vitro and in vivo models. METHODS The P. aeruginosa strains examined were parental strain PAO1 and isogenic mutant strain pvdE (ΔpvdE) defective in pyoverdine. Bacterial growth in vitro was determined by PAO1 and ΔpvdE optical densities in Luria-Bertani (LB) broth. PAO1 or ΔpvdE (10 colony-forming units/mL) was inoculated onto cultured human corneal epithelial cells (HCECs) for 1 hour. The monolayers were examined for bacterial adhesion and invasion. In addition, the corneas of C57BL/6 mice were infected with PAO1 or ΔpvdE. Corneal virulence was evaluated by determining clinical scores and bacterial counts during infection. RESULTS The growth of PAO1 and ΔpvdE in LB broth was similar. Although adhesion of ΔpvdE onto HCECs was significantly increased compared with PAO1, the invasive capacity of ΔpvdE was significantly decreased. Clinical scores and bacterial numbers were significantly lower in ΔpvdE-infected eyes compared with PAO1-infected eyes at 6, 24, and 48 hours (P < 0.001). ΔpvdE was not detected in mouse corneas and did not induce corneal opacity at 6, 24, or 48 hours. CONCLUSIONS ΔpvdE lost invasive ability toward HCECs. Moreover, ΔpvdE did not cause keratitis in vivo. Thus, pvdE pyoverdine synthesis has critical roles in proliferation and invasion on ocular surfaces and could be a target for prevention of P. aeruginosa keratitis.
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Garcia CJ, Pericleous A, Elsayed M, Tran M, Gupta S, Callaghan JD, Stella NA, Franks JM, Thibodeau PH, Shanks RMQ, Kadouri DE. Serralysin family metalloproteases protects Serratia marcescens from predation by the predatory bacteria Micavibrio aeruginosavorus. Sci Rep 2018; 8:14025. [PMID: 30232396 PMCID: PMC6145908 DOI: 10.1038/s41598-018-32330-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 09/03/2018] [Indexed: 12/16/2022] Open
Abstract
Micavibrio aeruginosavorus is an obligate Gram-negative predatory bacterial species that feeds on other Gram-negative bacteria by attaching to the surface of its prey and feeding on the prey's cellular contents. In this study, Serratia marcescens with defined mutations in genes for extracellular cell structural components and secreted factors were used in predation experiments to identify structures that influence predation. No change was measured in the ability of the predator to prey on S. marcescens flagella, fimbria, surface layer, prodigiosin and phospholipase-A mutants. However, higher predation was measured on S. marcescens metalloprotease mutants. Complementation of the metalloprotease gene, prtS, into the protease mutant, as well as exogenous addition of purified serralysin metalloprotease, restored predation to wild type levels. Addition of purified serralysin also reduced the ability of M. aeruginosavorus to prey on Escherichia coli. Incubating M. aeruginosavorus with purified metalloprotease was found to not impact predator viability; however, pre-incubating prey, but not the predator, with purified metalloprotease was able to block predation. Finally, using flow cytometry and fluorescent microscopy, we were able to confirm that the ability of the predator to bind to the metalloprotease mutant was higher than that of the metalloprotease producing wild-type. The work presented in this study shows that metalloproteases from S. marcescens could offer elevated protection from predation.
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Affiliation(s)
- Carlos J Garcia
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA
| | - Androulla Pericleous
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA
| | - Mennat Elsayed
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA
| | - Michael Tran
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA
| | - Shilpi Gupta
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA
| | - Jake D Callaghan
- Department of Ophthalmology, Charles T. Campbell Laboratory of Ophthalmic Microbiology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Nicholas A Stella
- Department of Ophthalmology, Charles T. Campbell Laboratory of Ophthalmic Microbiology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Jonathan M Franks
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Patrick H Thibodeau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, 15221, USA
| | - Robert M Q Shanks
- Department of Ophthalmology, Charles T. Campbell Laboratory of Ophthalmic Microbiology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Daniel E Kadouri
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, USA.
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Sylte I, Dawadi R, Malla N, von Hofsten S, Nguyen TM, Solli AI, Berg E, Adekoya OA, Svineng G, Winberg JO. The selectivity of galardin and an azasugar-based hydroxamate compound for human matrix metalloproteases and bacterial metalloproteases. PLoS One 2018; 13:e0200237. [PMID: 30075004 PMCID: PMC6075749 DOI: 10.1371/journal.pone.0200237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 06/22/2018] [Indexed: 02/07/2023] Open
Abstract
Inhibitors targeting bacterial enzymes should not interfere with enzymes of the host, and knowledge about structural determinants for selectivity is important for designing inhibitors with a therapeutic potential. We have determined the binding strengths of two hydroxamate compounds, galardin and compound 1b for the bacterial zinc metalloproteases, thermolysin, pseudolysin and auerolysin, known to be bacterial virulence factors, and the two human zinc metalloproteases MMP-9 and MMP-14. The active sites of the bacterial and human enzymes have huge similarities. In addition, we also studied the enzyme-inhibitor interactions by molecular modelling. The obtained Ki values of galardin for MMP-9 and MMP-14 and compound 1b for MMP-9 are approximately ten times lower than previously reported. Compound 1b binds stronger than galardin to both MMP-9 and MMP-14, and docking studies indicated that the diphenyl ether moiety of compound 1b obtains more favourable interactions within the S´1-subpocket than the 4-methylpentanoyl moiety of galardin. Both compounds bind stronger to MMP-9 than to MMP-14, which appears to be due to a larger S´1-subpocket in the former enzyme. Galardin, but not 1b, inhibits the bacterial enzymes, but the galardin Ki values were much larger than for the MMPs. The docking indicates that the S´1-subpockets of the bacterial proteases are too small to accommodate the diphenyl ether moiety of 1b, while the 4-methylpentanoyl moiety of galardin enters the pocket. The present study indicates that the size and shape of the ligand structural moiety entering the S´1-subpocket is an important determinant for selectivity between the studied MMPs and bacterial MPs.
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Affiliation(s)
- Ingebrigt Sylte
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Rangita Dawadi
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Nabin Malla
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Susannah von Hofsten
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Tra-Mi Nguyen
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Ann Iren Solli
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Eli Berg
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Olayiwola A. Adekoya
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Gunbjørg Svineng
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Jan-Olof Winberg
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
- * E-mail:
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Bastaert F, Kheir S, Saint-Criq V, Villeret B, Dang PMC, El-Benna J, Sirard JC, Voulhoux R, Sallenave JM. Pseudomonas aeruginosa LasB Subverts Alveolar Macrophage Activity by Interfering With Bacterial Killing Through Downregulation of Innate Immune Defense, Reactive Oxygen Species Generation, and Complement Activation. Front Immunol 2018; 9:1675. [PMID: 30083156 PMCID: PMC6064941 DOI: 10.3389/fimmu.2018.01675] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 07/06/2018] [Indexed: 12/25/2022] Open
Abstract
Pseudomonas aeruginosa (P.a) is a pathogen causing significant morbidity and mortality, in particular, in hospital patients undergoing ventilation and in patients with cystic fibrosis. Among the virulence factors secreted or injected into host cells, the physiopathological relevance of type II secretions system (T2SS) is less studied. Although there is extensive literature on the destructive role of LasB in vitro on secreted innate immune components and on some stromal cell receptors, studies on its direct action on myeloid cells are scant. Using a variety of methods, including the use of bacterial mutants, gene-targeted mice, and proteomics technology, we show here, using non-opsonic conditions (thus mimicking resting and naïve conditions in the alveolar space), that LasB, an important component of the P.a T2SS is highly virulent in vivo, and can subvert alveolar macrophage (AM) activity and bacterial killing, in vitro and in vivo by downregulating important secreted innate immune molecules (complement factors, cytokines, etc.) and receptors (IFNAR, Csf1r, etc.). In particular, we show that LasB downregulates the production of C3 and factor B complement molecules, as well as the activation of reactive oxygen species production by AM. In addition, we showed that purified LasB impaired significantly the ability of AM to clear an unrelated bacterium, namely Streptococcus pneumoniae. These data provide a new mechanism of action for LasB, potentially partly explaining the early onset of P.a, alone, or with other bacteria, within the alveolar lumen in susceptible individuals, such as ventilated, chronic obstructive pulmonary disease and cystic fibrosis patients.
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Affiliation(s)
- Fabien Bastaert
- INSERM, UMR1152, Paris, France.,Laboratoire d'Excellence Inflamex, Département Hospitalo-Universtaire FIRE (Fibrosis, Inflammation and Remodeling), University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Saadé Kheir
- INSERM, UMR1152, Paris, France.,Laboratoire d'Excellence Inflamex, Département Hospitalo-Universtaire FIRE (Fibrosis, Inflammation and Remodeling), University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Vinciane Saint-Criq
- INSERM, UMR1152, Paris, France.,Laboratoire d'Excellence Inflamex, Département Hospitalo-Universtaire FIRE (Fibrosis, Inflammation and Remodeling), University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Bérengère Villeret
- INSERM, UMR1152, Paris, France.,Laboratoire d'Excellence Inflamex, Département Hospitalo-Universtaire FIRE (Fibrosis, Inflammation and Remodeling), University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Pham My-Chan Dang
- INSERM UMR1149, ERL 8252 CNRS, Centre de Recherche sur l'Inflammation, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Jamel El-Benna
- INSERM UMR1149, ERL 8252 CNRS, Centre de Recherche sur l'Inflammation, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Jean-Claude Sirard
- Centre d'Infection et d'Immunité de Lille, Institut Pasteur de Lille, INSERM, U1019, Lille, CNRS, UMR 8204, Université de Lille, Lille, France
| | - Romé Voulhoux
- CNRS & Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée (IMM), Marseille, France
| | - Jean-Michel Sallenave
- INSERM, UMR1152, Paris, France.,Laboratoire d'Excellence Inflamex, Département Hospitalo-Universtaire FIRE (Fibrosis, Inflammation and Remodeling), University Paris Diderot, Sorbonne Paris Cité, Paris, France
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Pseudomonas aeruginosa Magnesium Transporter MgtE Inhibits Type III Secretion System Gene Expression by Stimulating rsmYZ Transcription. J Bacteriol 2017; 199:JB.00268-17. [PMID: 28847924 DOI: 10.1128/jb.00268-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/23/2017] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa causes numerous acute and chronic opportunistic infections in humans. One of its most formidable weapons is a type III secretion system (T3SS), which injects powerful toxins directly into host cells. The toxins lead to cell dysfunction and, ultimately, cell death. Identification of regulatory pathways that control T3SS gene expression may lead to the discovery of novel therapeutics to treat P. aeruginosa infections. In a previous study, we found that expression of the magnesium transporter gene mgtE inhibits T3SS gene transcription. MgtE-dependent inhibition appeared to interfere with the synthesis or function of the master T3SS transcriptional activator ExsA, although the exact mechanism was unclear. We now demonstrate that mgtE expression acts through the GacAS two-component system to activate rsmY and rsmZ transcription. This event ultimately leads to inhibition of exsA translation. This inhibitory effect is specific to exsA as translation of other genes in the exsCEBA operon is not inhibited by mgtE Moreover, our data reveal that MgtE acts solely through this pathway to regulate T3SS gene transcription. Our study reveals an important mechanism that may allow P. aeruginosa to fine-tune T3SS activity in response to certain environmental stimuli.IMPORTANCE The type III secretion system (T3SS) is a critical virulence factor utilized by numerous Gram-negative bacteria, including Pseudomonas aeruginosa, to intoxicate and kill host cells. Elucidating T3SS regulatory mechanisms may uncover targets for novel anti-P. aeruginosa therapeutics and provide deeper understanding of bacterial pathogenesis. We previously found that the magnesium transporter MgtE inhibits T3SS gene transcription in P. aeruginosa In this study, we describe the mechanism of MgtE-dependent inhibition of the T3SS. Our report also illustrates how MgtE might respond to environmental cues, such as magnesium levels, to fine-tune T3SS gene expression.
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36
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Flynn JM, Phan C, Hunter RC. Genome-Wide Survey of Pseudomonas aeruginosa PA14 Reveals a Role for the Glyoxylate Pathway and Extracellular Proteases in the Utilization of Mucin. Infect Immun 2017; 85:e00182-17. [PMID: 28507068 PMCID: PMC5520445 DOI: 10.1128/iai.00182-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/08/2017] [Indexed: 01/06/2023] Open
Abstract
Chronic airway infections by the opportunistic pathogen Pseudomonas aeruginosa are a major cause of mortality in cystic fibrosis (CF) patients. Although this bacterium has been extensively studied for its virulence determinants, biofilm growth, and immune evasion mechanisms, comparatively little is known about the nutrient sources that sustain its growth in vivo Respiratory mucins represent a potentially abundant bioavailable nutrient source, although we have recently shown that canonical pathogens inefficiently use these host glycoproteins as a growth substrate. However, given that P. aeruginosa, particularly in its biofilm mode of growth, is thought to grow slowly in vivo, the inefficient use of mucin glycoproteins may be relevant to its persistence within the CF airways. To this end, we used whole-genome fitness analysis, combining transposon mutagenesis with high-throughput sequencing, to identify genetic determinants required for P. aeruginosa growth using intact purified mucins as a sole carbon source. Our analysis reveals a biphasic growth phenotype, during which the glyoxylate pathway and amino acid biosynthetic machinery are required for mucin utilization. Secondary analyses confirmed the simultaneous liberation and consumption of acetate during mucin degradation and revealed a central role for the extracellular proteases LasB and AprA. Together, these studies describe a molecular basis for mucin-based nutrient acquisition by P. aeruginosa and reveal a host-pathogen dynamic that may contribute to its persistence within the CF airways.
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Affiliation(s)
- Jeffrey M Flynn
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Chi Phan
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ryan C Hunter
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
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Stella NA, Callaghan JD, Zhang L, Brothers KM, Kowalski RP, Huang JJ, Thibodeau PH, Shanks RMQ. SlpE is a calcium-dependent cytotoxic metalloprotease associated with clinical isolates of Serratia marcescens. Res Microbiol 2017; 168:567-574. [PMID: 28366837 PMCID: PMC5503780 DOI: 10.1016/j.resmic.2017.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/08/2017] [Accepted: 03/22/2017] [Indexed: 01/15/2023]
Abstract
Serralysin-like proteases are found in a wide variety of bacteria. These metalloproteases are frequently implicated in virulence and are members of the widely conserved RTX-toxin family. We identified a serralysin-like protease in the genome of a clinical isolate of Serratia marcescens that is highly similar to the canonical serralysin protein, PrtS. This gene was named serralysin-like protease E, SlpE, and was found in the majority (67%) of tested clinical isolates, but was absent from most tested non-clinical isolates including the insect pathogen and reference S. marcescens strain Db11. Purified recombinant SlpE exhibited calcium-dependent protease activity similar to metalloproteases PrtS and SlpB. Induction of slpE in the low-protease-producing S. marcescens strain PIC3611 highly elevated extracellular protease activity, and extracellular secretion required the lipD type 1 secretion system gene. Transcription of slpE was highly reduced in an eepR transcription factor mutant. Mutation of the slpE gene in a highly proteolytic clinical isolate reduced its protease activity, and evidence suggests that SlpE confers cytotoxicity of S. marcescens to the A549 airway carcinoma cell line. Together, these data reveal SlpE to be an EepR-regulated cytotoxic metalloprotease associated with clinical isolates of an important opportunistic pathogen.
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Affiliation(s)
- Nicholas A Stella
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jake D Callaghan
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Liang Zhang
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Kimberly M Brothers
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Regis P Kowalski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jean J Huang
- Department of Biology, Olin College, Needham, MA 02492, USA
| | - Patrick H Thibodeau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Robert M Q Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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Corich L, Busetti M, Petix V, Passamonti S, Bandiera A. Evaluation of a biomimetic 3D substrate based on the Human Elastin-like Polypeptides (HELPs) model system for elastolytic activity detection. J Biotechnol 2017. [PMID: 28624377 DOI: 10.1016/j.jbiotec.2017.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Elastin is a fibrous protein that confers elasticity to tissues such as skin, arteries and lung. It is extensively cross-linked, highly hydrophobic and insoluble. Nevertheless, elastin can be hydrolysed by bacterial proteases in infectious diseases, resulting in more or less severe tissue damage. Thus, development of substrates able to reliably and specifically detect pathogen-secreted elastolytic activity is needed to improve the in vitro evaluation of the injury that bacterial proteases may provoke. In this work, two human biomimetic elastin polypeptides, HELP and HELP1, as well as the matrices derived from HELP, have been probed as substrates for elastolytic activity detection. Thirty strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients were analyzed in parallel with standard substrates, to detect proteolytic and elastolytic activity. Results point to the HELP-based 3D matrix as an interesting biomimetic model of elastin to assess bacterial elastolytic activity in vitro. Moreover, this model substrate enables to further elucidate the mechanism underlying elastin degradation at molecular level, as well as to develop biomimetic material-based devices responsive to external stimuli.
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Affiliation(s)
- Lucia Corich
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy.
| | - Marina Busetti
- Microbiology Unit, University Hospital ASUITS, 34149, Trieste, Italy
| | - Vincenzo Petix
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, 34137, Trieste, Italy
| | - Sabina Passamonti
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Antonella Bandiera
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy.
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Hassuna NA. Molecular Detection of the Virulent ExoU Genotype of Pseudomonas aeruginosa Isolated from Infected Surgical Incisions. Surg Infect (Larchmt) 2016; 17:610-4. [PMID: 27441791 DOI: 10.1089/sur.2016.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Pseudomonas aeruginosa is one of the major pathogens responsible for hospital-acquired infections, which harbor a wide array of virulence factors. The main aim of this study was to determine the frequency of the virulent ExoU genotype in relation to the ExoS genotype among isolated P. aeruginosa from infected surgical incisions, followed by phylogenetic analysis. METHODS A total of 66 P. aeruginosa isolates were identified by cultural and biochemical characteristics. All isolates were tested for antimicrobial susceptibility against the following antimicrobial agents: imipenem, amikacin, gentamicin, amoxycillin, cefotaxime, cefepime, and levofloxacin. Molecular detection of the ExoS and ExoU as well as two other virulence genes was done by polymerase chain reaction (PCR). Sequencing of ExoU gene and phylogenetic analysis was performed. RESULTS Approximately 81% of the isolated P. aeruginosa were multi-drug resistant. The ExoS genotype was more prevalent (63%) among the isolates than the ExoU genotype (18%), with 9% of the isolates possessing both toxins. LasB and AprA were detected in 63.6% and 27.2% of the isolates, respectively. An association was observed between the number of virulence genes and the presence of multi-drug resistance. All the ExoU were multi-drug resistant (MDR), whereas 71% of the ExoS were MDR. Phylogenetic analysis of ExoU gene showed a 99% similarity with four different strains. CONCLUSION Despite the greater frequency of the ExoS genotype, the presence of the virulent MDR ExoU genotype isolates from surgical site infections is an alarming sign requiring further intervention and investigations.
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Affiliation(s)
- Noha A Hassuna
- Department of Microbiology and Immunology, Minia University , Minia, Egypt
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40
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van der Plas MJA, Bhongir RKV, Kjellström S, Siller H, Kasetty G, Mörgelin M, Schmidtchen A. Pseudomonas aeruginosa elastase cleaves a C-terminal peptide from human thrombin that inhibits host inflammatory responses. Nat Commun 2016; 7:11567. [PMID: 27181065 PMCID: PMC4873665 DOI: 10.1038/ncomms11567] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/08/2016] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen known for its immune evasive abilities amongst others by degradation of a large variety of host proteins. Here we show that digestion of thrombin by P. aeruginosa elastase leads to the release of the C-terminal thrombin-derived peptide FYT21, which inhibits pro-inflammatory responses to several pathogen-associated molecular patterns in vitro and in vivo by preventing toll-like receptor dimerization and subsequent activation of down-stream signalling pathways. Thus, P. aeruginosa 'hijacks' an endogenous anti-inflammatory peptide-based mechanism, thereby enabling modulation and circumvention of host responses.
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Affiliation(s)
- Mariena J A van der Plas
- Division of Dermatology and Venereology, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden
| | - Ravi K V Bhongir
- Division of Dermatology and Venereology, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden
| | - Sven Kjellström
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, PO Box 124, Lund SE-22362, Sweden
| | - Helena Siller
- Division of Dermatology and Venereology, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden
| | - Gopinath Kasetty
- Division of Dermatology and Venereology, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden
| | - Matthias Mörgelin
- Division of Infection Medicine, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden
| | - Artur Schmidtchen
- Division of Dermatology and Venereology, Department of Clinical Sciences Lund, Lund University, BMC, Tornavägen 10, Lund SE-22184, Sweden.,Dermatology and Venereology, Skane University Hospital, Lasarettsgatan 15, Lund SE-22185, Sweden.,Dermatology, LKCMedicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
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41
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Tallab RT, Stone DU. Corticosteroids as a therapy for bacterial keratitis: an evidence-based review of ‘who, when and why’. Br J Ophthalmol 2016; 100:731-5. [DOI: 10.1136/bjophthalmol-2015-307955] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/13/2015] [Indexed: 11/03/2022]
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43
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Chen CM, Liu JJ, Chou CW, Lai CH, Wu LT. RpA, an extracellular protease similar to the metalloprotease of serralysin family, is required for pathogenicity of Ralstonia pickettii. J Appl Microbiol 2015; 119:1101-11. [DOI: 10.1111/jam.12903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 07/05/2015] [Accepted: 07/07/2015] [Indexed: 11/25/2022]
Affiliation(s)
- C.-M. Chen
- Division of Infectious Disease; Department of Internal Medicine; Tungs' Taichung MetroHarbor Hospital; Taichung Taiwan
| | - J.-J. Liu
- The Institute of Medical Science and Department of Microbiology; China Medical University; Taichung Taiwan
| | - C.-W. Chou
- Department of Cosmeceutics; College of Pharmacy; China Medical University; Taichung Taiwan
| | - C.-H. Lai
- The Institute of Medical Science and Department of Microbiology; China Medical University; Taichung Taiwan
| | - L.-T. Wu
- The Institute of Medical Science and Department of Microbiology; China Medical University; Taichung Taiwan
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44
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Putting on the brakes: Bacterial impediment of wound healing. Sci Rep 2015; 5:14003. [PMID: 26365869 PMCID: PMC4650533 DOI: 10.1038/srep14003] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 12/17/2022] Open
Abstract
The epithelium provides a crucial barrier to infection, and its integrity requires
efficient wound healing. Bacterial cells and secretomes from a subset of tested
species of bacteria inhibited human and porcine corneal epithelial cell migration
in vitro and ex vivo. Secretomes from 95% of Serratia
marcescens, 71% of Pseudomonas aeruginosa, 29% of Staphylococcus
aureus strains, and other bacterial species inhibited epithelial cell
migration. Migration of human foreskin fibroblasts was also inhibited by S.
marcescens secretomes indicating that the effect is not cornea specific.
Transposon mutagenesis implicated lipopolysaccharide (LPS) core biosynthetic genes
as being required to inhibit corneal epithelial cell migration. LPS depletion of
S. marcescens secretomes with polymyxin B agarose rendered secretomes
unable to inhibit epithelial cell migration. Purified LPS from S. marcescens,
but not from Escherichia coli or S. marcescens strains with mutations
in the waaG and waaC genes, inhibited epithelial cell migration in
vitro and wound healing ex vivo. Together these data suggest that
S. marcescens LPS is sufficient for inhibition of epithelial wound
healing. This study presents a novel host-pathogen interaction with implications for
infections where bacteria impact wound healing and provides evidence that secreted
LPS is a key factor in the inhibitory mechanism.
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45
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EepR Mediates Secreted-Protein Production, Desiccation Survival, and Proliferation in a Corneal Infection Model. Infect Immun 2015; 83:4373-82. [PMID: 26324535 DOI: 10.1128/iai.00466-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 08/25/2015] [Indexed: 02/08/2023] Open
Abstract
Serratia marcescens is a soil- and water-derived bacterium that secretes several host-directed factors and causes hospital infections and community-acquired ocular infections. The putative two-component regulatory system composed of EepR and EepS regulates hemolysis and swarming motility through transcriptional control of the swrW gene and pigment production through control of the pigA-pigN operon. Here, we identify and characterize a role for EepR in regulation of exoenzyme production, stress survival, cytotoxicity to human epithelial cells, and virulence. Genetic analysis supports the model that EepR is in a common pathway with the widely conserved cyclic-AMP receptor protein that regulates protease production. Together, these data introduce a novel regulator of host-pathogen interactions and secreted-protein production.
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Identification of SlpB, a Cytotoxic Protease from Serratia marcescens. Infect Immun 2015; 83:2907-16. [PMID: 25939509 DOI: 10.1128/iai.03096-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/27/2015] [Indexed: 12/28/2022] Open
Abstract
The Gram-negative bacterium and opportunistic pathogen Serratia marcescens causes ocular infections in healthy individuals. Secreted protease activity was characterized from 44 ocular clinical isolates, and a higher frequency of protease-positive strains was observed among keratitis isolates than among conjunctivitis isolates. A positive correlation between protease activity and cytotoxicity to human corneal epithelial cells in vitro was determined. Deletion of prtS in clinical keratitis isolate K904 reduced, but did not eliminate, cytotoxicity and secreted protease production. This indicated that PrtS is necessary for full cytotoxicity to ocular cells and implied the existence of another secreted protease(s) and cytotoxic factors. Bioinformatic analysis of the S. marcescens Db11 genome revealed three additional open reading frames predicted to code for serralysin-like proteases noted here as slpB, slpC, and slpD. Induced expression of prtS and slpB, but not slpC and slpD, in strain PIC3611 rendered the strain cytotoxic to a lung carcinoma cell line; however, only prtS induction was sufficient for cytotoxicity to a corneal cell line. Strain K904 with deletion of both prtS and slpB genes was defective in secreted protease activity and cytotoxicity to human cell lines. PAGE analysis suggests that SlpB is produced at lower levels than PrtS. Purified SlpB demonstrated calcium-dependent and AprI-inhibited protease activity and cytotoxicity to airway and ocular cell lines in vitro. Lastly, genetic analysis indicated that the type I secretion system gene, lipD, is required for SlpB secretion. These genetic data introduce SlpB as a new cytotoxic protease from S. marcescens.
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Yang J, Zhao HL, Ran LY, Li CY, Zhang XY, Su HN, Shi M, Zhou BC, Chen XL, Zhang YZ. Mechanistic insights into elastin degradation by pseudolysin, the major virulence factor of the opportunistic pathogen Pseudomonas aeruginosa. Sci Rep 2015; 5:9936. [PMID: 25905792 PMCID: PMC4407726 DOI: 10.1038/srep09936] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 03/12/2015] [Indexed: 01/01/2023] Open
Abstract
Pseudolysin is the most abundant protease secreted by Pseudomonas aeruginosa and is the major extracellular virulence factor of this opportunistic human pathogen. Pseudolysin destroys human tissues by solubilizing elastin. However, the mechanisms by which pseudolysin binds to and degrades elastin remain elusive. In this study, we investigated the mechanism of action of pseudolysin on elastin binding and degradation by biochemical assay, microscopy and site-directed mutagenesis. Pseudolysin bound to bovine elastin fibers and preferred to attack peptide bonds with hydrophobic residues at the P1 and P1’ positions in the hydrophobic domains of elastin. The time-course degradation processes of both bovine elastin fibers and cross-linked human tropoelastin by pseudolysin were further investigated by microscopy. Altogether, the results indicate that elastin degradation by pseudolysin began with the hydrophobic domains on the fiber surface, followed by the progressive disassembly of macroscopic elastin fibers into primary structural elements. Moreover, our site-directed mutational results indicate that five hydrophobic residues in the S1-S1’ sub-sites played key roles in the binding of pseudolysin to elastin. This study sheds lights on the pathogenesis of P. aeruginosa infection.
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Affiliation(s)
- Jie Yang
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Hui-Lin Zhao
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Li-Yuan Ran
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Chun-Yang Li
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Xi-Ying Zhang
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Hai-Nan Su
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Mei Shi
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Bai-Cheng Zhou
- Biotechnology Research Center, Shandong University, Jinan 250100, China
| | - Xiu-Lan Chen
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China [3] Collaborative Innovation Center of Deep Sea Biology, Shandong University, Jinan 250100, China
| | - Yu-Zhong Zhang
- 1] State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China [2] Biotechnology Research Center, Shandong University, Jinan 250100, China [3] Collaborative Innovation Center of Deep Sea Biology, Shandong University, Jinan 250100, China
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Ravichandran A, Ramachandran M, Suriyanarayanan T, Wong CC, Swarup S. Global Regulator MorA Affects Virulence-Associated Protease Secretion in Pseudomonas aeruginosa PAO1. PLoS One 2015; 10:e0123805. [PMID: 25894344 PMCID: PMC4404142 DOI: 10.1371/journal.pone.0123805] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 03/06/2015] [Indexed: 11/18/2022] Open
Abstract
Bacterial invasion plays a critical role in the establishment of Pseudomonas aeruginosa infection and is aided by two major virulence factors--surface appendages and secreted proteases. The second messenger cyclic diguanylate (c-di-GMP) is known to affect bacterial attachment to surfaces, biofilm formation and related virulence phenomena. Here we report that MorA, a global regulator with GGDEF and EAL domains that was previously reported to affect virulence factors, negatively regulates protease secretion via the type II secretion system (T2SS) in P. aeruginosa PAO1. Infection assays with mutant strains carrying gene deletion and domain mutants show that host cell invasion is dependent on the active domain function of MorA. Further investigations suggest that the MorA-mediated c-di-GMP signaling affects protease secretion largely at a post-translational level. We thus report c-di-GMP second messenger system as a novel regulator of T2SS function in P. aeruginosa. Given that T2SS is a central and constitutive pump, and the secreted proteases are involved in interactions with the microbial surroundings, our data broadens the significance of c-di-GMP signaling in P. aeruginosa pathogenesis and ecological fitness.
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Affiliation(s)
- Ayshwarya Ravichandran
- Metabolites Biology Lab, Department of Biological Sciences, National University of Singapore, Singapore 117543
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411
| | - Malarmathy Ramachandran
- Metabolites Biology Lab, Department of Biological Sciences, National University of Singapore, Singapore 117543
| | - Tanujaa Suriyanarayanan
- Metabolites Biology Lab, Department of Biological Sciences, National University of Singapore, Singapore 117543
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University 60 Nanyang Drive, SBS-01N-27 Singapore 637551
| | - Chui Ching Wong
- Metabolites Biology Lab, Department of Biological Sciences, National University of Singapore, Singapore 117543
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411
| | - Sanjay Swarup
- Metabolites Biology Lab, Department of Biological Sciences, National University of Singapore, Singapore 117543
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411
- NUS Environmental Research Institute (NERI), National University of Singapore, 5A Engineering Drive 1, Singapore 117411
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University 60 Nanyang Drive, SBS-01N-27 Singapore 637551
- * E-mail:
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Lakshmi Priya J, Prajna L, Mohankumar V. Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from post-cataract endophthalmitis patients. Microb Pathog 2015; 78:67-73. [DOI: 10.1016/j.micpath.2014.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 11/08/2014] [Accepted: 11/26/2014] [Indexed: 11/24/2022]
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Said DG, Elalfy MS, Gatzioufas Z, El-Zakzouk ES, Hassan MA, Saif MY, Zaki AA, Dua HS, Hafezi F. Collagen Cross-Linking with Photoactivated Riboflavin (PACK-CXL) for the Treatment of Advanced Infectious Keratitis with Corneal Melting. Ophthalmology 2014; 121:1377-82. [DOI: 10.1016/j.ophtha.2014.01.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 01/05/2014] [Accepted: 01/07/2014] [Indexed: 10/25/2022] Open
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