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Lê-Bury P, Echenique-Rivera H, Pizarro-Cerdá J, Dussurget O. Determinants of bacterial survival and proliferation in blood. FEMS Microbiol Rev 2024; 48:fuae013. [PMID: 38734892 PMCID: PMC11163986 DOI: 10.1093/femsre/fuae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 04/29/2024] [Accepted: 05/10/2024] [Indexed: 05/13/2024] Open
Abstract
Bloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis, and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood.
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Affiliation(s)
- Pierre Lê-Bury
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Autoimmune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT), 18 route du Panorama, 92260 Fontenay-aux-Roses, France
| | - Hebert Echenique-Rivera
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
| | - Javier Pizarro-Cerdá
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Yersinia National Reference Laboratory, WHO Collaborating Research & Reference Centre for Plague FRA-146, 28 rue du Dr Roux, 75015 Paris, France
| | - Olivier Dussurget
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
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2
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Abe R, Ram-Mohan N, Yang S. Re-visiting humoral constitutive antibacterial heterogeneity in bloodstream infections. THE LANCET. INFECTIOUS DISEASES 2024; 24:e245-e251. [PMID: 37944543 DOI: 10.1016/s1473-3099(23)00494-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/03/2023] [Accepted: 07/25/2023] [Indexed: 11/12/2023]
Abstract
Although cellular immunity has garnered much attention in the era of single-cell technologies, humoral innate immunity has receded in priority due to its presumed limited roles. Hence, despite the long-recognised bactericidal activity of serum-a functional characteristic of constitutive humoral immunity-much remains unclear regarding mechanisms underlying its inter-individual heterogeneity and clinical implications in bloodstream infections. Recent work suggests that the immediate antimicrobial effect of humoral innate immunity contributes to suppression of the excessive inflammatory responses to infection by reducing the amount of pathogen-associated molecular patterns. In this Personal View, we propose the need to re-explore factors underlying the inter-individual heterogeneity in serum antibacterial competence as a new approach to better understand humoral innate immunity and revisit the clinical use of measuring serum antibacterial activity in the management of bacterial bloodstream infections. Given the current emphasis on subtyping sepsis, a serum bactericidal assay might prove useful in defining a distinct sepsis endotype, to enable more personalised management.
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Affiliation(s)
- Ryuichiro Abe
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA.
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3
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Wu KY, Cao B, Chen WB, Wu W, Zhao S, Min XY, Yang J, Han J, Dong X, Wang N, Wu Y, Garred P, Sacks SH, Zhou W, Li K. Collectin 11 has a pivotal role in host defense against kidney and bladder infection in mice. Kidney Int 2024; 105:524-539. [PMID: 38158182 DOI: 10.1016/j.kint.2023.11.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 11/11/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024]
Abstract
The urinary tract is constantly exposed to microorganisms. Host defense mechanisms in protection from microbial colonization and development of urinary tract infections require better understanding to control kidney infection. Here we report that the lectin collectin 11 (CL-11), particularly kidney produced, has a pivotal role in host defense against uropathogen infection. CL-11 was found in mouse urine under normal and pathological conditions. Mice with global gene ablation of Colec11 had increased susceptibility to and severity of kidney and to an extent, bladder infection. Mice with kidney-specific Colec11 ablation exhibited a similar disease phenotype to that observed in global Colec11 deficient mice, indicating the importance of kidney produced CL-11 for protection against kidney and bladder infection. Conversely, intravesical or systemic administration of recombinant CL-11 reduced susceptibility to and severity of kidney and bladder infection. Mechanism analysis revealed that CL-11 can mediate several key innate defense mechanisms (agglutination, anti- adhesion, opsonophagocytosis), and limit local inflammatory responses to pathogens. Furthermore, CL-11-mediated innate defense mechanisms can act on clinically relevant microorganisms including multiple antibiotic resistant strains. CL-11 was detectable in eight of 24 urine samples from patients with urinary tract infections but not detectable in urine samples from ten healthy individuals. Thus, our findings demonstrate that CL-11 is a key factor of host defense mechanisms in kidney and bladder infection with therapeutic potential for human application.
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Affiliation(s)
- Kun-Yi Wu
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Bo Cao
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wan-Bing Chen
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Weiju Wu
- Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Shujuan Zhao
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Xiao-Yun Min
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Jurong Yang
- Department of Nephrology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jin Han
- Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Xia Dong
- Department of Ophthalmology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong, China
| | - Na Wang
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Yi Wu
- MOE Key Laboratory of Environment and Genes Related to Diseases, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - Steven H Sacks
- Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Wuding Zhou
- Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK.
| | - Ke Li
- Core Research Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China.
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Duffin RN, Andrews PC. Enhanced antibacterial activity of dimethyl gallium quinolinolates toward drug-resistant Klebsiella pneumoniae in low iron environments. J Inorg Biochem 2023; 249:112371. [PMID: 37738699 DOI: 10.1016/j.jinorgbio.2023.112371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/04/2023] [Accepted: 09/12/2023] [Indexed: 09/24/2023]
Abstract
A series of dimethylgallium quinolinolate [GaMe2L] (L = 5-chloroquinolinolate, 5, 7-dichloroquinolinolate, 5, 7-dibromoquinolinolate or 5, 7-doiodoquinolinolate) complexes, shown previously to be active toward the Leishmania parasite, have been studied for their antibacterial activity toward a reference and drug resistant strain of Klebsiella pneumoniae (KP). The assays were conducted in standard iron-rich LB media and in the iron depleted RPMI and RPMI-HS media to better understand the effect of Fe concentration on the activity of the Ga complexes. In LB broth the parent quinolinols and the gallium complexes were inactive up to the highest concentration tested, 100 μM. In the more physiologically relevant 'iron-poor' RPMI-HS media the quinolonols remained inactive, however, the gallium complexes showed exceptional activity in the range 48-195 nM. Only in RPMI without any added HS did both the quinolinols and the gallium complexes show good activity. The significant differences in activity across the various media types suggest that the unnaturally high iron content of conventional LB media may provide false negative results for potentially potent Ga therapeutics. A protein binding assay on the organometallic gallium complexes showed a much slower uptake of Ga by Fe-binding proteins than is typically observed for gallium salts. This indicates that their greater lipophilicity and greater hydrolytic stability could account for their increased biological activity in RPMI-HS media.
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Affiliation(s)
- Rebekah N Duffin
- School of Chemistry, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Philip C Andrews
- School of Chemistry, Monash University, Clayton, Melbourne, VIC 3800, Australia.
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Yang F, Zhou Y, Bai Y, Pan X, Ha UH, Cheng Z, Wu W, Jin Y, Bai F. MvfR Controls Tolerance to Polymyxin B by Regulating rfaD in Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0042623. [PMID: 37039709 PMCID: PMC10269820 DOI: 10.1128/spectrum.00426-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/18/2023] [Indexed: 04/12/2023] Open
Abstract
Polymyxins are currently the last-resort antibiotics for the treatment of multidrug-resistant Gram-negative bacterial infections. To expand the understanding of the intrinsic resistance mechanism against polymyxins, a laboratory strain of Pseudomonas aeruginosa PAO1 was subjected to serial passage in the presence of sublethal doses of polymyxin B over a period of 30 days. By whole-genome sequencing of successively isolated polymyxin B-resistant isolates, we identified a frameshift mutation (L183fs) in the mvfR gene that further increased polymyxin resistance in the pmrB mutant background. A ΔmvfR mutation alone showed higher tolerance to polymyxin B due to altered lipopolysaccharide (LPS) on the surface of bacterial cells, which decreases its outer membrane permeability. In the ΔmvfR mutant, polymyxin B treatment caused the upregulation of rfaD, the gene involved in LPS core oligosaccharide synthesis, which is responsible for polymyxin tolerance. To the best of our knowledge, this is the first report of mvfR mutation conferring polymyxin resistance in P. aeruginosa via increased integrity of bacterial outer membrane. IMPORTANCE Antibiotic resistance imposes a considerable challenge for the treatment of P. aeruginosa infections. Polymyxins are the last-resort antibiotics for the treatment of multidrug-resistant P. aeruginosa infections. Understanding the development and mechanisms of bacterial resistance to polymyxins may provide clues for the development of new or improved therapeutic strategies effective against P. aeruginosa. In this study, using an in vitro evolution assay in combination with whole-genome sequencing, we demonstrated that MvfR controls tolerance to polymyxin B by regulating the rfaD gene in P. aeruginosa. Our results reveal a novel mechanism employed by P. aeruginosa in the defense against polymyxin antibiotics.
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Affiliation(s)
- Fan Yang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuchen Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuxi Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Un-Hwan Ha
- Department of Biotechnology and Bioinformatics, Korea University, Sejong, Republic of Korea
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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Yeh JC, Hazam PK, Hsieh CY, Hsu PH, Lin WC, Chen YR, Li CC, Chen JY. Rational Design of Stapled Antimicrobial Peptides to Enhance Stability and In Vivo Potency against Polymicrobial Sepsis. Microbiol Spectr 2023; 11:e0385322. [PMID: 36877022 PMCID: PMC10101059 DOI: 10.1128/spectrum.03853-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 02/17/2023] [Indexed: 03/07/2023] Open
Abstract
In this work, we sought to develop a TP4-based stapled peptide that can be used to counter polymicrobial sepsis. First, we segregated the TP4 sequence into hydrophobic and cationic/hydrophilic zones and substituted the preferred residue, lysine, as the sole cationic amino acid. These modifications minimized the intensity of cationic or hydrophobic characteristics within small segments. Then, we incorporated single or multiple staples into the peptide chain, bracketing the cationic/hydrophilic segments to improve pharmacological suitability. Using this approach, we were able to develop an AMP with low toxicity and notable in vivo efficacy. IMPORTANCE In our in vitro studies, one dual stapled peptide out of the series of candidates (TP4-3: FIIXKKSXGLFKKKAGAXKKKXIKK) showed significant activity, low toxicity, and high stability (in 50% human serum). When tested in cecal ligation and puncture (CLP) mouse models of polymicrobial sepsis, TP4-3 improved survival (87.5% on day 7). Furthermore, TP4-3 enhanced the activity of meropenem against polymicrobial sepsis (100% survival on day 7) compared to meropenem alone (37.5% survival on day 7). Molecules such as TP4-3 may be well suited for a wide variety of clinical applications.
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Affiliation(s)
- Jih-Chao Yeh
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, Taiwan
| | - Prakash Kishore Hazam
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, Taiwan
| | - Chu-Yi Hsieh
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, Taiwan
| | - Po-Hsien Hsu
- Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan
| | - Wen-Chun Lin
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, Taiwan
| | - Yun-Ru Chen
- Academia Sinica Protein Clinic, Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chao-Chin Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Jyh-Yih Chen
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, Taiwan
- The iEGG and Animal Biotechnology Center and the Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
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7
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Downs CJ, Schoenle LA, Goolsby EW, Oakey SJ, Ball R, Jiang RHY, Martin LB. Large Mammals Have More Powerful Antibacterial Defenses Than Expected from Their Metabolic Rates. Am Nat 2023; 201:287-301. [PMID: 36724463 DOI: 10.1086/722504] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AbstractTerrestrial mammals span seven orders of magnitude in body size, ranging from the <2-g Etruscan pygmy shrew (Suncus etruscus) to the >3,900-kg African elephant (Loxodonta africana). Although body size profoundly affects the behavior, physiology, ecology, and evolution of species, how investment in functional immune defenses changes with body size across species is unknown. Here, we (1) developed a novel 12-point dilution curve approach to describe and compare antibacterial capacity against three bacterial species among >160 terrestrial species of mammals and (2) tested published predictions about the scaling of immune defenses. Our study focused on the safety factor hypothesis, which predicts that broad, early-acting immune defenses should scale hypermetrically with body mass. However, our three statistical approaches demonstrated that antibacterial activity in sera across mammals exhibits isometry; killing capacity did not change with body size across species. Intriguingly, this result indicates that the serum of a large mammal is less hospitable to bacteria than would be predicted by its metabolic rates. In other words, if metabolic rates underlie the rates of physiological reactions as postulated by the metabolic theory of ecology, large species should have disproportionately lower antibacterial capacity than small species, but they do not. These results have direct implications for effectively modeling the evolution of immune defenses and identifying potential reservoir hosts of pathogens.
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Effect of Atmospheric Conditions on Pathogenic Phenotypes of Arcobacter butzleri. Microorganisms 2022; 10:microorganisms10122409. [PMID: 36557662 PMCID: PMC9785646 DOI: 10.3390/microorganisms10122409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
Arcobacter butzleri is an emergent gram-negative enteropathogenic bacterium widespread in different environments and hosts. During the colonization of the gastrointestinal tract, bacteria face a variety of environmental conditions to successfully establish infection in a new host. One of these challenges is the fluctuation of oxygen concentrations encountered not only throughout the host gastrointestinal tract and defences but also in the food industry. Oxygen fluctuations can lead to modulations in the virulence of the bacterium and possibly increase its pathogenic potential. In this sense, eight human isolates of A. butzleri were studied to evaluate the effects of microaerobic and aerobic atmospheric conditions in stressful host conditions, such as oxidative stress, acid survival, and human serum survival. In addition, the effects on the modulation of virulence traits, such as haemolytic activity, bacterial motility, biofilm formation ability, and adhesion and invasion of the Caco-2 cell line, were also investigated. Overall, aerobic conditions negatively affected the susceptibility to oxygen reactive species and biofilm formation ability but improved the isolates' haemolytic ability and motility while other traits showed an isolate-dependent response. In summary, this work demonstrates for the first time that oxygen levels can modulate the potential pathogenicity of A. butzleri, although the response to stressful conditions was very heterogeneous among different strains.
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Siggins MK, MacLennan CA. An adsorption method to prepare specific antibody-depleted normal human serum as a source of complement for human serum bactericidal assays for Salmonella. Vaccine 2021; 39:7503-7509. [PMID: 34794820 DOI: 10.1016/j.vaccine.2021.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 10/19/2022]
Abstract
Serum bactericidal assays (SBA) are valuable for assessing the functional activity of natural and vaccine-induced antibodies against many Gram-negative bacteria, such as meningococcus and Salmonella. However, SBA often require an exogenous source of complement and the presence of pre-existing naturally acquired antibodies limits the use of human complement for this purpose. To remove pre-existing Salmonella-specific antibodies, in the context of SBA for Salmonella vaccine research, we incubated human sera with preparations of Salmonella. By incubating at 4 °C, pre-existing antibodies were adsorbed onto the Salmonella bacteria with only minimal complement deposition. We assessed the effects of adsorption on specific antibody levels, complement activity and the bactericidal activity of sera using flow cytometry, SBA and haemolytic assays. Adsorption removed Salmonella-specific antibodies and bactericidal activity against Salmonella from whole serum but was not detrimental to serum complement activity, even after five adsorption cycles. Bactericidal activity could be reconstituted in the adsorbed serum by the addition of exogenous specific antibodies. Sera preadsorbed with Salmonella are suitable as a source of human complement to measure the bactericidal activity of Salmonella antibodies. The adsorption method can be used to deplete, simply and rapidly, specific antibodies from serum to prepare a source of human complement for use in SBA for vaccine research and assessment.
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Affiliation(s)
- Matthew K Siggins
- The Institute of Immunology and Immunotherapy, University of Birmingham, B15 2TT, United Kingdom; National Heart and Lung Institute, St Mary's Hospital, Faculty of Medicine, Imperial College London, W2 1PG, United Kingdom.
| | - Calman A MacLennan
- The Institute of Immunology and Immunotherapy, University of Birmingham, B15 2TT, United Kingdom; The Jenner Institute, Nuffield Department of Medicine, University of Oxford, OX3 7DQ, United Kingdom; Bill & Melinda Gates Foundation, 62 Buckingham Gate, London SW1E 6AJ, United Kingdom.
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Zaknoon F, Meir O, Mor A. Mechanistic Studies of Antibiotic Adjuvants Reducing Kidney's Bacterial Loads upon Systemic Monotherapy. Pharmaceutics 2021; 13:pharmaceutics13111947. [PMID: 34834362 PMCID: PMC8621570 DOI: 10.3390/pharmaceutics13111947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/11/2021] [Accepted: 11/14/2021] [Indexed: 12/01/2022] Open
Abstract
We describe the design and attributes of a linear pentapeptide-like derivative (C14(ω5)OOc10O) screened for its ability to elicit bactericidal competences of plasma constituents against Gram-negative bacteria (GNB). In simpler culture media, the lipopeptide revealed high aptitudes to sensitize resilient GNB to hydrophobic and/or efflux-substrate antibiotics, whereas in their absence, C14(ω5)OOc10O only briefly delayed bacterial proliferation. Instead, at low micromolar concentrations, the lipopeptide has rapidly lowered bacterial proton and ATP levels, although significantly less than upon treatment with its bactericidal analog. Mechanistic studies support a two-step scenario providing a plausible explanation for the lipopeptide’s biological outcomes against GNB: initially, C14(ω5)OOc10O permeabilizes the outer membrane similarly to polymyxin B, albeit in a manner not necessitating as much LPS-binding affinity. Subsequently, C14(ω5)OOc10O would interact with the inner membrane gently yet intensively enough to restrain membrane-protein functions such as drug efflux and/or ATP generation, while averting the harsher inner membrane perturbations that mediate the fatal outcome associated with bactericidal peers. Preliminary in vivo studies where skin wound infections were introduced in mice, revealed a significant efficacy in affecting bacterial viability upon topical treatment with creams containing C14(ω5)OOc10O, whereas synergistic combination therapies were able to secure the pathogen’s eradication. Further, capitalizing on the finding that C14(ω5)OOc10O plasma-potentiating concentrations were attainable in mice blood at sub-maximal tolerated doses, we used a urinary tract infection model to acquire evidence for the lipopeptide’s systemic capacity to reduce the kidney’s bacterial loads. Collectively, the data establish the role of C14(ω5)OOc10O as a compelling antibacterial potentiator and suggest its drug-like potential.
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11
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Doorduijn DJ, Heesterbeek DAC, Ruyken M, de Haas CJC, Stapels DAC, Aerts PC, Rooijakkers SHM, Bardoel BW. Polymerization of C9 enhances bacterial cell envelope damage and killing by membrane attack complex pores. PLoS Pathog 2021; 17:e1010051. [PMID: 34752492 PMCID: PMC8604303 DOI: 10.1371/journal.ppat.1010051] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 11/19/2021] [Accepted: 10/20/2021] [Indexed: 11/21/2022] Open
Abstract
Complement proteins can form membrane attack complex (MAC) pores that directly kill Gram-negative bacteria. MAC pores assemble by stepwise binding of C5b, C6, C7, C8 and finally C9, which can polymerize into a transmembrane ring of up to 18 C9 monomers. It is still unclear if the assembly of a polymeric-C9 ring is necessary to sufficiently damage the bacterial cell envelope to kill bacteria. In this paper, polymerization of C9 was prevented without affecting binding of C9 to C5b-8, by locking the first transmembrane helix domain of C9. Using this system, we show that polymerization of C9 strongly enhanced damage to both the bacterial outer and inner membrane, resulting in more rapid killing of several Escherichia coli and Klebsiella strains in serum. By comparing binding of wildtype and ‘locked’ C9 by flow cytometry, we also show that polymerization of C9 is impaired when the amount of available C9 per C5b-8 is limited. This suggests that an excess of C9 is required to efficiently form polymeric-C9. Finally, we show that polymerization of C9 was impaired on complement-resistant E. coli strains that survive killing by MAC pores. This suggests that these bacteria can specifically block polymerization of C9. All tested complement-resistant E. coli expressed LPS O-antigen (O-Ag), compared to only one out of four complement-sensitive E. coli. By restoring O-Ag expression in an O-Ag negative strain, we show that the O-Ag impairs polymerization of C9 and results in complement-resistance. Altogether, these insights are important to understand how MAC pores kill bacteria and how bacterial pathogens can resist MAC-dependent killing. In this paper, we focus on how complement proteins, an essential part of the immune system, kill Gram-negative bacteria via so-called membrane attack complex (MAC) pores. The MAC is a large pore that consists of five different proteins. The final component, C9, assembles a ring of up to 18 C9 molecules that damages the bacterial cell envelope. Here, we aimed to better understand if this polymeric-C9 ring is necessary to kill bacteria and if bacteria can interfere in its assembly. We uncover that polymerization of C9 increased the damage to the entire bacterial cell envelope, which resulted in more rapid killing of several Gram-negative species. We also show that some clinical Escherichia coli strains can block polymerization of C9 and survive MAC-dependent killing by modifying sugars in the bacterial cell envelope, namely the O-antigen of lipopolysaccharide. These insights help us to better understand how the immune system kills bacteria and how pathogenic bacteria can survive killing.
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Affiliation(s)
- Dennis J. Doorduijn
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dani A. C. Heesterbeek
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maartje Ruyken
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Carla J. C. de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Daphne A. C. Stapels
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Piet C. Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bart W. Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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12
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Whole Genome Sequencing Based Taxonomic Classification, and Comparative Genomic Analysis of Potentially Human Pathogenic Enterobacter spp. Isolated from Chlorinated Wastewater in the North West Province, South Africa. Microorganisms 2021; 9:microorganisms9091928. [PMID: 34576823 PMCID: PMC8466087 DOI: 10.3390/microorganisms9091928] [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: 08/17/2021] [Revised: 09/04/2021] [Accepted: 09/05/2021] [Indexed: 11/17/2022] Open
Abstract
Comparative genomics, in particular, pan-genome analysis, provides an in-depth understanding of the genetic variability and dynamics of a bacterial species. Coupled with whole-genome-based taxonomic analysis, these approaches can help to provide comprehensive, detailed insights into a bacterial species. Here, we report whole-genome-based taxonomic classification and comparative genomic analysis of potential human pathogenic Enterobacter hormaechei subsp. hoffmannii isolated from chlorinated wastewater. Genome Blast Distance Phylogeny (GBDP), digital DNA-DNA hybridization (dDDH), and average nucleotide identity (ANI) confirmed the identity of the isolates. The algorithm PathogenFinder predicted the isolates to be human pathogens with a probability of greater than 0.78. The potential pathogenic nature of the isolates was supported by the presence of biosynthetic gene clusters (BGCs), aerobactin, and aryl polyenes (APEs), which are known to be associated with pathogenic/virulent strains. Moreover, analysis of the genome sequences of the isolates reflected the presence of an arsenal of virulence factors and antibiotic resistance genes that augment the predictions of the algorithm PathogenFinder. The study comprehensively elucidated the genomic features of pathogenic Enterobacter isolates from wastewaters, highlighting the role of wastewaters in the dissemination of pathogenic microbes, and the need for monitoring the effectiveness of the wastewater treatment process.
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13
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An Outer Membrane Vesicle-Adjuvanted Oral Vaccine Protects Against Lethal, Oral Salmonella Infection. Pathogens 2021; 10:pathogens10050616. [PMID: 34069796 PMCID: PMC8157261 DOI: 10.3390/pathogens10050616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 11/23/2022] Open
Abstract
Non-typhoidal salmonellosis, caused by Salmonella enterica serovar Typhimurium is a common fecal-oral disease characterized by mild gastrointestinal distress resulting in diarrhea, chills, fever, abdominal cramps, head and body aches, nausea, and vomiting. Increasing incidences of antibiotic resistant invasive non-typhoidal Salmonella infections makes this a global threat requiring novel treatment strategies including next-generation vaccines. The goal of the current study was to formulate a novel vaccine platform against Salmonella infection that could be delivered orally. To accomplish this, we created a Salmonella-specific vaccine adjuvanted with Burkholderia pseudomallei outer membrane vesicles (OMVs). We show that adding OMVs to a heat-killed oral Salmonella vaccine (HKST + OMVs) protects against a lethal, oral challenge with Salmonella. Further, we show that opsonizing anti-Salmonella antibodies are induced in response to immunization and that CD4 T cells and B cells can be induced when OMVs are used as the oral adjuvant. This study represents a novel oral vaccine approach to combatting the increasing problem of invasive Salmonella infections.
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14
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Heesterbeek DAC, Muts RM, van Hensbergen VP, de Saint Aulaire P, Wennekes T, Bardoel BW, van Sorge NM, Rooijakkers SHM. Outer membrane permeabilization by the membrane attack complex sensitizes Gram-negative bacteria to antimicrobial proteins in serum and phagocytes. PLoS Pathog 2021; 17:e1009227. [PMID: 33481964 PMCID: PMC7886145 DOI: 10.1371/journal.ppat.1009227] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/16/2021] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
Infections with Gram-negative bacteria form an increasing risk for human health due to antibiotic resistance. Our immune system contains various antimicrobial proteins that can degrade the bacterial cell envelope. However, many of these proteins do not function on Gram-negative bacteria, because the impermeable outer membrane of these bacteria prevents such components from reaching their targets. Here we show that complement-dependent formation of Membrane Attack Complex (MAC) pores permeabilizes this barrier, allowing antimicrobial proteins to cross the outer membrane and exert their antimicrobial function. Specifically, we demonstrate that MAC-dependent outer membrane damage enables human lysozyme to degrade the cell wall of E. coli. Using flow cytometry and confocal microscopy, we show that the combination of MAC pores and lysozyme triggers effective E. coli cell wall degradation in human serum, thereby altering the bacterial cell morphology from rod-shaped to spherical. Completely assembled MAC pores are required to sensitize E. coli to the antimicrobial actions of lysozyme and other immune factors, such as Human Group IIA-secreted Phospholipase A2. Next to these effects in a serum environment, we observed that the MAC also sensitizes E. coli to more efficient degradation and killing inside human neutrophils. Altogether, this study serves as a proof of principle on how different players of the human immune system can work together to degrade the complex cell envelope of Gram-negative bacteria. This knowledge may facilitate the development of new antimicrobials that could stimulate or work synergistically with the immune system. In this paper we identified how different players of the human immune system cooperate to degrade the complex cell envelope of Gram-negative bacteria. The outer membrane of Gram-negative bacteria forms an impermeable barrier for various antimicrobial proteins of the immune system. Here we show that complement-dependent Membrane Attack Complex (MAC) formation permeabilizes this barrier, allowing otherwise impermeable antimicrobial proteins to reach their targets underneath the outer membrane. Specifically, we show that outer membrane damage by the MAC allows lysozyme to degrade the peptidoglycan layer, and secreted phospholipase A2-IIA to hydrolyze the bacterial inner membrane. MAC formation also sensitizes Gram-negative bacteria to more efficient degradation and killing inside human neutrophils. Altogether, this knowledge may guide the development of new antimicrobial strategies to treat infections caused by Gram-negative bacteria.
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Affiliation(s)
- Dani A. C. Heesterbeek
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Remy M. Muts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Vincent P. van Hensbergen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Pieter de Saint Aulaire
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Tom Wennekes
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Bart W. Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Nina M. van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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15
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Woo XY, Giordano J, Srivastava A, Zhao ZM, Lloyd MW, de Bruijn R, Suh YS, Patidar R, Chen L, Scherer S, Bailey MH, Yang CH, Cortes-Sanchez E, Xi Y, Wang J, Wickramasinghe J, Kossenkov AV, Rebecca VW, Sun H, Mashl RJ, Davies SR, Jeon R, Frech C, Randjelovic J, Rosains J, Galimi F, Bertotti A, Lafferty A, O’Farrell AC, Modave E, Lambrechts D, ter Brugge P, Serra V, Marangoni E, El Botty R, Kim H, Kim JI, Yang HK, Lee C, Dean DA, Davis-Dusenbery B, Evrard YA, Doroshow JH, Welm AL, Welm BE, Lewis MT, Fang B, Roth JA, Meric-Bernstam F, Herlyn M, Davies MA, Ding L, Li S, Govindan R, Isella C, Moscow JA, Trusolino L, Byrne AT, Jonkers J, Bult CJ, Medico E, Chuang JH. Conservation of copy number profiles during engraftment and passaging of patient-derived cancer xenografts. Nat Genet 2021; 53:86-99. [PMID: 33414553 PMCID: PMC7808565 DOI: 10.1038/s41588-020-00750-6] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 11/18/2020] [Indexed: 02/03/2023]
Abstract
Patient-derived xenografts (PDXs) are resected human tumors engrafted into mice for preclinical studies and therapeutic testing. It has been proposed that the mouse host affects tumor evolution during PDX engraftment and propagation, affecting the accuracy of PDX modeling of human cancer. Here, we exhaustively analyze copy number alterations (CNAs) in 1,451 PDX and matched patient tumor (PT) samples from 509 PDX models. CNA inferences based on DNA sequencing and microarray data displayed substantially higher resolution and dynamic range than gene expression-based inferences, and they also showed strong CNA conservation from PTs through late-passage PDXs. CNA recurrence analysis of 130 colorectal and breast PT/PDX-early/PDX-late trios confirmed high-resolution CNA retention. We observed no significant enrichment of cancer-related genes in PDX-specific CNAs across models. Moreover, CNA differences between patient and PDX tumors were comparable to variations in multiregion samples within patients. Our study demonstrates the lack of systematic copy number evolution driven by the PDX mouse host.
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Grants
- NC/T001267/1 National Centre for the Replacement, Refinement and Reduction of Animals in Research
- P30 CA016672 NCI NIH HHS
- 29567 Cancer Research UK
- U54 CA233223 NCI NIH HHS
- P30 CA034196 NCI NIH HHS
- P01 CA114046 NCI NIH HHS
- HHSN261201400008C NCI NIH HHS
- P30 CA091842 NCI NIH HHS
- U24 CA224067 NCI NIH HHS
- P50 CA196510 NCI NIH HHS
- U54 CA224070 NCI NIH HHS
- U54 CA224076 NCI NIH HHS
- U54 CA224065 NCI NIH HHS
- U54 CA233306 NCI NIH HHS
- P30 CA010815 NCI NIH HHS
- U24 CA204781 NCI NIH HHS
- U54 CA224083 NCI NIH HHS
- HHSN261201500003C NCI NIH HHS
- HHSN261200800001C NCI NIH HHS
- T32 HG008962 NHGRI NIH HHS
- R50 CA211199 NCI NIH HHS
- P30 CA125123 NCI NIH HHS
- P50 CA070907 NCI NIH HHS
- HHSN261201500003I NCI NIH HHS
- HHSN261200800001E NCI NIH HHS
- P30 CA042014 NCI NIH HHS
- U.S. Department of Health & Human Services | NIH | National Cancer Institute (NCI)
- KWF Kankerbestrijding (Dutch Cancer Society)
- Oncode Institute
- Fondazione AIRC under 5 per Mille 2018 - ID. 21091 EU H2020 Research and Innovation Programme, grant agreement no. 731105 European Research Council Consolidator Grant 724748
- EU H2020 Research and Innovation Programme, grant Agreement No. 754923
- EU H2020 Research and Innovation Programme, grant agreement no. 731105 ISCIII - Miguel Servet program CP14/00228 GHD-Pink/FERO Foundation grant
- Fondazione Piemontese per la Ricerca sul Cancro-ONLUS 5 per mille Ministero della Salute 2015
- Korean Health Industry Development Institute HI13C2148
- Korean Health Industry Development Institute HI13C2148 The First Affiliated Hospital of Xi’an Jiaotong University Ewha Womans University Research Grant
- CPRIT RP170691
- SCU | Ignatian Center for Jesuit Education, Santa Clara University
- Breast Cancer Research Foundation (BCRF)
- Fashion Footwear Charitable Foundation of New York The Foundation for Barnes-Jewish Hospital’s Cancer Frontier Fund
- My First AIRC Grant 19047
- Fondazione AIRC under 5 per Mille 2018 - ID. 21091 AIRC Investigator Grants 18532 and 20697 AIRC/CRUK/FC AECC Accelerator Award 22795 Fondazione Piemontese per la Ricerca sul Cancro-ONLUS 5 per mille Ministero della Salute 2015, 2014, 2016 EU H2020 Research and Innovation Programme, grant Agreement No. 754923 EU H2020 Research and Innovation Programme, grant agreement no. 731105
- Science Foundation Ireland (SFI)
- EU H2020 Research and Innovation Programme, grant agreement no. 731105 EU H2020 Research and Innovation Programme, grant Agreement No. 754923 Irish Health Research Board grant ILP-POR-2019-066
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands Organisation for Scientific Research)
- EU H2020 Research and Innovation Programme, grant agreement no. 731105 European Research Council (ERC) Synergy project CombatCancer Oncode Institute
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Affiliation(s)
- Xing Yi Woo
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
| | - Jessica Giordano
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Anuj Srivastava
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
| | - Zi-Ming Zhao
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
| | - Michael W. Lloyd
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
| | - Roebi de Bruijn
- grid.430814.aNetherlands Cancer Institute, Amsterdam, the Netherlands
| | - Yun-Suhk Suh
- grid.31501.360000 0004 0470 5905College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Rajesh Patidar
- grid.418021.e0000 0004 0535 8394Frederick National Laboratory for Cancer Research, Frederick, MD USA
| | - Li Chen
- grid.418021.e0000 0004 0535 8394Frederick National Laboratory for Cancer Research, Frederick, MD USA
| | - Sandra Scherer
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA
| | - Matthew H. Bailey
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA ,grid.223827.e0000 0001 2193 0096Department of Human Genetics, University of Utah, Salt Lake City, UT USA
| | - Chieh-Hsiang Yang
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA
| | - Emilio Cortes-Sanchez
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA
| | - Yuanxin Xi
- grid.240145.60000 0001 2291 4776Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Jing Wang
- grid.240145.60000 0001 2291 4776Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | | | | | - Vito W. Rebecca
- grid.251075.40000 0001 1956 6678The Wistar Institute, Philadelphia, PA USA
| | - Hua Sun
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - R. Jay Mashl
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Sherri R. Davies
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Ryan Jeon
- grid.492568.4Seven Bridges Genomics, Charlestown, MA USA
| | | | | | | | - Francesco Galimi
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Andrea Bertotti
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Adam Lafferty
- grid.4912.e0000 0004 0488 7120Department of Physiology and Medical Physics, Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Alice C. O’Farrell
- grid.4912.e0000 0004 0488 7120Department of Physiology and Medical Physics, Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Elodie Modave
- grid.5596.f0000 0001 0668 7884Center for Cancer Biology, VIB, Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Diether Lambrechts
- grid.5596.f0000 0001 0668 7884Center for Cancer Biology, VIB, Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Petra ter Brugge
- grid.430814.aNetherlands Cancer Institute, Amsterdam, the Netherlands
| | - Violeta Serra
- grid.411083.f0000 0001 0675 8654Vall d´Hebron Institute of Oncology, Barcelona, Spain
| | - Elisabetta Marangoni
- grid.418596.70000 0004 0639 6384Department of Translational Research, Institut Curie, PSL Research University, Paris, France
| | - Rania El Botty
- grid.418596.70000 0004 0639 6384Department of Translational Research, Institut Curie, PSL Research University, Paris, France
| | - Hyunsoo Kim
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
| | - Jong-Il Kim
- grid.31501.360000 0004 0470 5905College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Han-Kwang Yang
- grid.31501.360000 0004 0470 5905College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Charles Lee
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA ,grid.452438.cPrecision Medicine Center, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, People’s Republic of China ,grid.255649.90000 0001 2171 7754Department of Life Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Dennis A. Dean
- grid.492568.4Seven Bridges Genomics, Charlestown, MA USA
| | | | - Yvonne A. Evrard
- grid.418021.e0000 0004 0535 8394Frederick National Laboratory for Cancer Research, Frederick, MD USA
| | - James H. Doroshow
- grid.48336.3a0000 0004 1936 8075Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD USA
| | - Alana L. Welm
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA
| | - Bryan E. Welm
- grid.223827.e0000 0001 2193 0096Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA ,grid.223827.e0000 0001 2193 0096Department of Surgery, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT USA
| | - Michael T. Lewis
- grid.39382.330000 0001 2160 926XLester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX USA
| | - Bingliang Fang
- grid.240145.60000 0001 2291 4776Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Jack A. Roth
- grid.240145.60000 0001 2291 4776Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Funda Meric-Bernstam
- grid.240145.60000 0001 2291 4776Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Meenhard Herlyn
- grid.251075.40000 0001 1956 6678The Wistar Institute, Philadelphia, PA USA
| | - Michael A. Davies
- grid.240145.60000 0001 2291 4776Department of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Li Ding
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Shunqiang Li
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Ramaswamy Govindan
- grid.4367.60000 0001 2355 7002Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Claudio Isella
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Jeffrey A. Moscow
- grid.48336.3a0000 0004 1936 8075Investigational Drug Branch, National Cancer Institute, Bethesda, MD USA
| | - Livio Trusolino
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Annette T. Byrne
- grid.4912.e0000 0004 0488 7120Department of Physiology and Medical Physics, Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jos Jonkers
- grid.430814.aNetherlands Cancer Institute, Amsterdam, the Netherlands
| | - Carol J. Bult
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME USA
| | - Enzo Medico
- grid.7605.40000 0001 2336 6580Department of Oncology, University of Turin, Turin, Italy ,grid.419555.90000 0004 1759 7675Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Jeffrey H. Chuang
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
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16
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An Intranasal Vaccination with a Recombinant Outer Membrane Protein H against Haemorrhagic Septicemia in Swamp Buffaloes. Vet Med Int 2020; 2020:3548973. [PMID: 32547726 PMCID: PMC7271248 DOI: 10.1155/2020/3548973] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/19/2020] [Accepted: 05/09/2020] [Indexed: 12/17/2022] Open
Abstract
Hemorrhagic septicemia (HS) is an important infectious disease in cattle and buffaloes, caused by Pasteurella multocida B:2 and E:2. The intranasal recombinant OmpH-based vaccine was successfully used to protect dairy cattle from HS in a previous study. Thus, this study aimed to examine the protective ability of that vaccine among buffaloes. Four groups of Thai swamp buffaloes received different vaccines and were labeled as 100 or 200 μg of the rOmpH with CpG-ODN2007, commercial HS bacterin vaccine, and nonvaccinated control groups. Sera and whole blood were collected to examine the antibody levels and cellular immune response using indirect ELISA and MTT assay, respectively. Challenge exposure was performed with virulent P. multocida strain M-1404 serotype B:2 on day 72 of the experiment. The antibody titers to P. multocida among immunized buffaloes were significantly higher than in the control group (p < 0.01), especially the 200 μg of the rOmpH group. The stimulation index (SI) of the intranasally vaccinated groups revealed significantly higher levels than the nonvaccinated group (p < 0.01), but not different from the intramuscularly commercial HS vaccine. The clinical signs and high fever were observed after challenge exposure in the nonvaccinated group, while it was not observed among the 200 μg of rOmpH immunized buffaloes. The other immunized groups showed partial protection with transient fever. In conclusion, the rOmpH-based intranasal vaccine could elicit protective ability and induce antibody- and cell-mediated immune response against virulent P. multocida strain among swamp buffaloes.
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17
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Larsson P, Engqvist H, Biermann J, Werner Rönnerman E, Forssell-Aronsson E, Kovács A, Karlsson P, Helou K, Parris TZ. Optimization of cell viability assays to improve replicability and reproducibility of cancer drug sensitivity screens. Sci Rep 2020; 10:5798. [PMID: 32242081 PMCID: PMC7118156 DOI: 10.1038/s41598-020-62848-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/25/2020] [Indexed: 12/01/2022] Open
Abstract
Cancer drug development has been riddled with high attrition rates, in part, due to poor reproducibility of preclinical models for drug discovery. Poor experimental design and lack of scientific transparency may cause experimental biases that in turn affect data quality, robustness and reproducibility. Here, we pinpoint sources of experimental variability in conventional 2D cell-based cancer drug screens to determine the effect of confounders on cell viability for MCF7 and HCC38 breast cancer cell lines treated with platinum agents (cisplatin and carboplatin) and a proteasome inhibitor (bortezomib). Variance component analysis demonstrated that variations in cell viability were primarily associated with the choice of pharmaceutical drug and cell line, and less likely to be due to the type of growth medium or assay incubation time. Furthermore, careful consideration should be given to different methods of storing diluted pharmaceutical drugs and use of DMSO controls due to the potential risk of evaporation and the subsequent effect on dose-response curves. Optimization of experimental parameters not only improved data quality substantially but also resulted in reproducible results for bortezomib- and cisplatin-treated HCC38, MCF7, MCF-10A, and MDA-MB-436 cells. Taken together, these findings indicate that replicability (the same analyst re-performs the same experiment multiple times) and reproducibility (different analysts perform the same experiment using different experimental conditions) for cell-based drug screens can be improved by identifying potential confounders and subsequent optimization of experimental parameters for each cell line.
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Affiliation(s)
- Peter Larsson
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
| | - Hanna Engqvist
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Jana Biermann
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Elisabeth Werner Rönnerman
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Eva Forssell-Aronsson
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Anikó Kovács
- Department of Clinical Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Per Karlsson
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Khalil Helou
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Toshima Z Parris
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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18
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Taha M, Kyluik‐Price D, Kumaran D, Scott MD, Toyofuku W, Ramirez‐Arcos S. Bacterial survival in whole blood depends on plasma sensitivity and resistance to neutrophil killing. Transfusion 2019; 59:3674-3682. [DOI: 10.1111/trf.15550] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Mariam Taha
- Centre for Innovation, Canadian Blood Services Ottawa Ontario
| | - Dana Kyluik‐Price
- Centre for Blood Research, University of British Columbia Vancouver British Columbia
| | - Dilini Kumaran
- Centre for Innovation, Canadian Blood Services Ottawa Ontario
| | - Mark D. Scott
- Centre for Innovation, Canadian Blood Services Ottawa Ontario
- Centre for Blood Research, University of British Columbia Vancouver British Columbia
| | - Wendy Toyofuku
- Centre for Innovation, Canadian Blood Services Ottawa Ontario
| | - Sandra Ramirez‐Arcos
- Centre for Innovation, Canadian Blood Services Ottawa Ontario
- Department of Biochemistry, Microbiology and ImmunologyUniversity of Ottawa Ottawa Ontario Canada
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19
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Doorduijn DJ, Rooijakkers SHM, Heesterbeek DAC. How the Membrane Attack Complex Damages the Bacterial Cell Envelope and Kills Gram‐Negative Bacteria. Bioessays 2019; 41:e1900074. [DOI: 10.1002/bies.201900074] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/11/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Dennis J. Doorduijn
- Medical Microbiology, University Medical Center UtrechtUtrecht University Heidelberglaan 100 3584 CX Utrecht The Netherlands
| | - Suzan H. M. Rooijakkers
- Medical Microbiology, University Medical Center UtrechtUtrecht University Heidelberglaan 100 3584 CX Utrecht The Netherlands
| | - Dani A. C. Heesterbeek
- Medical Microbiology, University Medical Center UtrechtUtrecht University Heidelberglaan 100 3584 CX Utrecht The Netherlands
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20
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Complement Susceptibility in Relation to Genome Sequence of Recent Klebsiella pneumoniae Isolates from Thai Hospitals. mSphere 2018; 3:3/6/e00537-18. [PMID: 30404929 PMCID: PMC6222052 DOI: 10.1128/msphere.00537-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The capacity to resist the bactericidal action of complement (C') is a strong but poorly understood virulence trait in Klebsiella spp. Killing requires activation of one or more C' pathways, assembly of C5b-9 membrane attack complexes (MACs) on the surface of the outer membrane (OM), and penetration of MACs into the target bilayer. We interrogated whole-genome sequences of 164 Klebsiella isolates from three tertiary hospitals in Thailand for genes encoding surface-located macromolecules considered to play a role in determination of C' resistance. Most isolates (154/164) were identified as Klebsiella pneumoniae, and the collection conformed to previously established population structures and antibiotic resistance patterns. The distribution of sequence types (STs) and capsular (K) types were also typical of global populations. The majority (64%) of isolates were resistant to C', and the remainder were either rapidly or slowly killed. All isolates carried genes encoding capsular polysaccharides (K antigens), which have been strongly linked to C' resistance. In contrast to previous reports, there were no differences in the amount of capsule produced by C'-resistant isolates compared to C'-susceptible isolates, nor was there any correlation between serum reactivity and the presence of hypermucoviscous capsules. Similarly, there were no correlations between the presence of genes specifying lipopolysaccharide O-side chains or major OM proteins. Some virulence factors were found more frequently in C'-resistant isolates but were considered to reflect clonal ST expansion. Thus, no single gene accounts for the C' resistance of the isolates sequenced in this study.IMPORTANCE Multidrug-resistant Klebsiella pneumoniae is responsible for an increasing proportion of nosocomial infections, and emerging hypervirulent K. pneumoniae clones now cause severe community-acquired infections in otherwise healthy individuals. These bacteria are adept at circumventing immune defenses, and most survive and grow in serum; their capacity to avoid C'-mediated destruction is correlated with their invasive potential. Killing of Gram-negative bacteria occurs following activation of the C' cascades and stable deposition of C5b-9 MACs onto the OM. For Klebsiella, studies with mutants and conjugants have invoked capsules, lipopolysaccharide O-side chains, and OM proteins as determinants of C' resistance, although the precise roles of the macromolecules are unclear. In this study, we sequenced 164 Klebsiella isolates with different C' susceptibilities to identify genes involved in resistance. We conclude that no single OM constituent can account for resistance, which is likely to depend on biophysical properties of the target bilayer.
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Age-related variations in the in vitro bactericidal activity of human sera against Pseudomonas aeruginosa. Cent Eur J Immunol 2018; 43:18-25. [PMID: 29731689 PMCID: PMC5927169 DOI: 10.5114/ceji.2018.74869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/18/2017] [Indexed: 01/03/2023] Open
Abstract
The human serum is a vital component of the innate immunity of the host that acts as the first line of defence against invading pathogens. A key player in serum-mediated innate immune defence is a system of more than 35 proteins, collectively named as the complement system. After exposure of the pathogen, these proteins are activated in a cascade manner, ultimately forming a membrane attack complex (MAC) on the surface of the pathogen that directly lyses the bacterial cell. Formation of the MAC can be demonstrated in vitro by using serum bactericidal assay (SBA) that works in the absence of cellular components of blood after incubating the serum along with bacteria. Here, we describe the age-related differences in the bactericidal activity of human serum against Pseudomonas aeruginosa, an opportunistic human pathogen causing an array of hospital and community-acquired infections. We demonstrate that adult sera were highly effective in the in vitro killing of Pseudomonas aeruginosa as compared to children and the elderly (p < 0.0001). Sera from children were seriously compromised in the killing P. aeruginosa, whereas elderly sera showed a reduced level of killing. Data revealed a positive correlation between age and serum-killing with higher coefficient of determination values of 0.34, 0.27, and 0.58 and p values of < 0.0001, < 0.001, and < 0.0001, respectively, after 60, 90, and 120 minutes of incubation. Hence, our study highlights the age-related difference in the bactericidal activity of human sera. We conclude that sera of children are totally compromised, whereas elderly sera are only partially compromised, in the killing of P. aeruginosa.
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22
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Li K, Wu KY, Wu W, Wang N, Zhang T, Choudhry N, Song Y, Farrar CA, Ma L, Wei LL, Duan ZY, Dong X, Liu EQ, Li ZF, Sacks SH, Zhou W. C5aR1 promotes acute pyelonephritis induced by uropathogenic E. coli. JCI Insight 2017; 2:97626. [PMID: 29263309 PMCID: PMC5752266 DOI: 10.1172/jci.insight.97626] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/21/2017] [Indexed: 02/01/2023] Open
Abstract
C5a receptor 1 (C5aR1) is a G protein-coupled receptor for C5a and also an N-linked glycosylated protein. In addition to myeloid cells, C5aR1 is expressed on epithelial cells. In this study, we examined the role of C5aR1 in bacterial adhesion/colonization of renal tubular epithelium and addressed the underlying mechanisms of this role. We show that acute kidney infection was significantly reduced in mice with genetic deletion or through pharmacologic inhibition of C5aR1 following bladder inoculation with uropathogenic E. coli (UPEC). This was associated with reduced expression of terminal α-mannosyl residues (Man; a ligand for type 1 fimbriae of E. coli) on the luminal surface of renal tubular epithelium and reduction of early UPEC colonization in these mice. Confocal microscopy demonstrated that UPEC bind to Man on the luminal surface of renal tubular epithelium. In vitro analyses showed that C5a stimulation enhances Man expression in renal tubular epithelial cells and subsequent bacterial adhesion, which, at least in part, is dependent on TNF-α driven by C5aR1-mediated intracellular signaling. Our findings demonstrate a previously unknown pathogenic role for C5aR1 in acute pyelonephritis, proposing a potentially novel mechanism by which C5a/C5aR1 signaling mediates upregulation of carbohydrate ligands on renal tubules to facilitate UPEC adhesion.
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Affiliation(s)
- Ke Li
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Kun-Yi Wu
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Weiju Wu
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - Na Wang
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Ting Zhang
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Naheed Choudhry
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - Yun Song
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Conrad A Farrar
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - Liang Ma
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - Lin-Lin Wei
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Zhao-Yang Duan
- Department of Nephrology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Xia Dong
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - En-Qi Liu
- Research Institute of Atherosclerotic Disease, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Zong-Fang Li
- National Local Joint Engineering Research Centre of Biodiagnostics and Biotherapy, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Steven H Sacks
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
| | - Wuding Zhou
- Medical Research Council (MRC) Centre for Transplantation, King's College London, Guy's Hospital, United Kingdom (UK)
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23
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Blom AM, Magda M, Kohl L, Shaughnessy J, Lambris JD, Ram S, Ermert D. Factor H-IgG Chimeric Proteins as a Therapeutic Approach against the Gram-Positive Bacterial Pathogen Streptococcus pyogenes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 199:3828-3839. [PMID: 29084837 PMCID: PMC5698128 DOI: 10.4049/jimmunol.1700426] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 09/30/2017] [Indexed: 11/19/2022]
Abstract
Bacteria can cause life-threatening infections, such as pneumonia, meningitis, or sepsis. Antibiotic therapy is a mainstay of treatment, although antimicrobial resistance has drastically increased over the years. Unfortunately, safe and effective vaccines against most pathogens have not yet been approved, and thus developing alternative treatments is important. We analyzed the efficiency of factor H (FH)6-7/Fc, a novel antibacterial immunotherapeutic protein against the Gram-positive bacterium Streptococcus pyogenes This protein is composed of two domains of complement inhibitor human FH (FH complement control protein modules 6 and 7) that bind to S. pyogenes, linked to the Fc region of IgG (FH6-7/Fc). FH6-7/Fc has previously been shown to enhance complement-dependent killing of, and facilitate bacterial clearance in, animal models of the Gram-negative pathogens Haemophilus influenzae and Neisseria meningitidis We hypothesized that activation of complement by FH6-7/Fc on the surface of Gram-positive bacteria such as S. pyogenes will enable professional phagocytes to eliminate the pathogen. We found that FH6-7/Fc alleviated S. pyogenes-induced sepsis in a transgenic mouse model expressing human FH (S. pyogenes binds FH in a human-specific manner). Furthermore, FH6-7/Fc, which binds to protein H and selected M proteins, displaced FH from the bacterial surface, enhanced alternative pathway activation, and reduced bacterial blood burden by opsonophagocytosis in a C3-dependent manner in an ex vivo human whole-blood model. In conclusion, FH-Fc chimeric proteins could serve as adjunctive treatments against multidrug-resistant bacterial infections.
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Affiliation(s)
- Anna M Blom
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Michal Magda
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Lisa Kohl
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - David Ermert
- Department of Translational Medicine, Medical Protein Chemistry, Lund University, Skåne County Council, Malmö 20502, Sweden;
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605; and
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24
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Pawlak A, Rybka J, Dudek B, Krzyżewska E, Rybka W, Kędziora A, Klausa E, Bugla-Płoskońska G. Salmonella O48 Serum Resistance is Connected with the Elongation of the Lipopolysaccharide O-Antigen Containing Sialic Acid. Int J Mol Sci 2017; 18:E2022. [PMID: 28934165 PMCID: PMC5666704 DOI: 10.3390/ijms18102022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/09/2017] [Accepted: 09/12/2017] [Indexed: 12/27/2022] Open
Abstract
Complement is one of the most important parts of the innate immune system. Some bacteria can gain resistance against the bactericidal action of complement by decorating their outer cell surface with lipopolysaccharides (LPSs) containing a very long O-antigen or with specific outer membrane proteins. Additionally, the presence of sialic acid in the LPS molecules can provide a level of protection for bacteria, likening them to human cells, a phenomenon known as molecular mimicry. Salmonella O48, which contains sialic acid in the O-antigen, is the major cause of reptile-associated salmonellosis, a worldwide public health problem. In this study, we tested the effect of prolonged exposure to human serum on strains from Salmonella serogroup O48, specifically on the O-antigen length. After multiple passages in serum, three out of four tested strains became resistant to serum action. The gas-liquid chromatography/tandem mass spectrometry analysis showed that, for most of the strains, the average length of the LPS O-antigen increased. Thus, we have discovered a link between the resistance of bacterial cells to serum and the elongation of the LPS O-antigen.
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Affiliation(s)
- Aleksandra Pawlak
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Jacek Rybka
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Bartłomiej Dudek
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Eva Krzyżewska
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Wojciech Rybka
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
| | - Anna Kędziora
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
| | - Elżbieta Klausa
- Regional Centre of Transfusion Medicine and Blood Bank, 50-345 Wrocław, Poland.
| | - Gabriela Bugla-Płoskońska
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, 51-148 Wrocław, Poland.
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25
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Abreu AG, Barbosa AS. How Escherichia coli Circumvent Complement-Mediated Killing. Front Immunol 2017; 8:452. [PMID: 28473832 PMCID: PMC5397495 DOI: 10.3389/fimmu.2017.00452] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 12/19/2022] Open
Abstract
Complement is a crucial arm of the innate immune response against invading bacterial pathogens, and one of its main functions is to recognize and destroy target cells. Similar to other pathogens, Escherichia coli has evolved mechanisms to overcome complement activation. It is well known that capsular polysaccharide may confer resistance to complement-mediated killing and phagocytosis, being one of the strategies adopted by this bacterium to survive in serum. In addition, proteases produced by E. coli have been shown to downregulate the complement system. Pic, an autotransporter secreted by different pathogens in the Enterobacteriaceae family, is able to cleave C2, C3/C3b, and C4/C4b and works synergistically with human Factor I and Factor H (FH), thereby promoting inactivation of C3b. Extracellular serine protease P, a serine protease of enterohemorrhagic E. coli (EHEC), downregulates complement activation by cleaving C3/C3b and C5. StcE, a metalloprotease secreted by EHEC, inhibits the classical complement-mediated cell lysis by potentiating the action of C1 inhibitor, and the periplasmic protease Prc contributes to E. coli complement evasion by interfering with the classical pathway activation and by preventing membrane attack complex deposition. Finally, it has been described that E. coli proteins interact with negative complement regulators to modulate complement activation. The functional consequences resulting from the interaction of outer membrane protein A, new lipoprotein I, outer membrane protein W, and Stx2 with proteins of the FH family and C4b-binding protein (C4BP) are discussed in detail. In brief, in this review, we focused on the different mechanisms used by pathogenic E. coli to circumvent complement attack, allowing these bacteria to promote a successful infection.
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Affiliation(s)
- Afonso G Abreu
- Programa de Pós-Graduação em Biologia Parasitária, CEUMA University, São Luís, Brazil.,Programa de Pós-Graduação em Ciências da Saúde, Federal University of Maranhão, São Luís, Brazil
| | - Angela S Barbosa
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
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26
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Ataei Kachooei S, Ranjbar MM, Ataei Kachooei S. Evaluation of Pasteurella multocida serotype B:2 resistance to immune serum and complement system. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2017; 8:179-184. [PMID: 29085604 PMCID: PMC5653880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 05/24/2017] [Indexed: 10/26/2022]
Abstract
Members of gram-negative bacteria family Pasteurellaceae, include a large number of important economically human and veterinary pathogens. Organisms belonging to the family can colonize in mucosal surfaces of the respiratory, alimentary, genital tracts and cause diseases in various mammals, birds, and reptiles. Hemorrhagic septicemia is an acute disease of cattle and buffaloes in tropical countries caused by Pasteurella multocida serotype B:2. In the present study, the possible bactericidal activity of immune calf sera in the presence and absence of complement system was investigated. The results showed that P. multocida B:2 is highly resistant to positive serum, containing high levels of IgG and IgM obtained from calves after vaccination, and complement activity in normal fresh calf serum. This organism also grew rapidly in the normal fresh calf serum and the mixture of positive serum as well as normal fresh calf serum. As a control test an E. coli strain was subjected to the same experiment and found completely sensitive to the bactericidal activity of complement in calf and guinea pig fresh sera. Results were indicative of the presence of inhibitory mechanism(s) in P. multocida B:2 against bactericidal activity of immune calf serum and complement system.
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Affiliation(s)
- Saeed Ataei Kachooei
- Department of Bacterial Poultry Diseases, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran;,Correspondence: Saeed Ataei Kachooei. PhD, Department of Bacterial Poultry Diseases, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. E-mail:
| | - Mohammad Mehdi Ranjbar
- Department of Animal Virology, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran;
| | - Saba Ataei Kachooei
- Department of Life Sciences, Faculty of Life Sciences, Kharazmi University, Karaj, Iran
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27
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Choudhry N, Li K, Zhang T, Wu KY, Song Y, Farrar CA, Wang N, Liu CF, Peng Q, Wu W, Sacks SH, Zhou W. The complement factor 5a receptor 1 has a pathogenic role in chronic inflammation and renal fibrosis in a murine model of chronic pyelonephritis. Kidney Int 2016; 90:540-54. [PMID: 27370410 PMCID: PMC4996631 DOI: 10.1016/j.kint.2016.04.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 04/12/2016] [Accepted: 04/28/2016] [Indexed: 02/07/2023]
Abstract
Complement factor 5a (C5a) interaction with its receptor (C5aR1) contributes to the pathogenesis of inflammatory diseases, including acute kidney injury. However, its role in chronic inflammation, particularly in pathogen-associated disorders, is largely unknown. Here we tested whether the development of chronic inflammation and renal fibrosis is dependent on C5aR1 in a murine model of chronic pyelonephritis. C5aR1-deficient (C5aR1-/-) mice showed a significant reduction in bacterial load, tubule injury and tubulointerstitial fibrosis in the kidneys following infection, compared with C5aR1-sufficient mice. This was associated with reduced renal leukocyte infiltration specifically for the population of Ly6Chi proinflammatory monocytes/macrophages and reduced intrarenal gene expression of key proinflammatory and profibrogenic factors in C5aR1-/- mice following infection. Antagonizing C5aR1 decreased renal bacterial load, tissue inflammation and tubulointerstitial fibrosis. Ex vivo and in vitro studies showed that under infection conditions, C5a/C5aR1 interaction upregulated the production of proinflammatory and profibrogenic factors by renal tubular epithelial cells and monocytes/macrophages, whereas the phagocytic function of monocytes/macrophages was down-regulated. Thus, C5aR1-dependent bacterial colonization of the tubular epithelium, C5a/C5aR1-mediated upregulation of local inflammatory responses to uropathogenic E. coli and impairment of phagocytic function of phagocytes contribute to persistent bacterial colonization of the kidney, chronic renal inflammation and subsequent tubulointerstitial fibrosis.
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Affiliation(s)
- Naheed Choudhry
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - Ke Li
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
| | - Ting Zhang
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Kun-Yi Wu
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Yun Song
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Conrad A Farrar
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - Na Wang
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Cheng-Fei Liu
- Core Research Laboratory, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Qi Peng
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - Weiju Wu
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - Steven H Sacks
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - Wuding Zhou
- Medical Research Council Centre for Transplantation, King's College London, Guy's Hospital, London, UK.
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28
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López-Medrano R, Guerra-Laso JM, López-Fidalgo E, Diez-Tascón C, García-García S, Blanco-Conde S, Rivero-Lezcano OM. Plasma contributes to the antimicrobial activity of whole blood against Mycobacterium tuberculosis. Innate Immun 2016; 22:557-66. [PMID: 27554054 DOI: 10.1177/1753425916663311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/29/2016] [Indexed: 11/16/2022] Open
Abstract
The whole blood model for infection has proven useful to analyze the immunological response to Mycobacterium tuberculosis, because it exerts a significant antimicrobial activity. Although this activity has been generally assumed to be cellular, we have found that the leukocyte fraction of blood from healthy volunteers did not kill the bacilli. We have discovered that plasma was responsible for a large proportion, but not all, of the antimicrobial activity. Furthermore, infected monocytes controlled the mycobacterial multiplication when cultivated in the presence of plasma. Intriguingly, serum from the same donors did not share this activity, although it was able to eliminate the non-pathogenic Mycobacterium gordonae To identify the remaining components that participate in the antimycobacterial activity we fractionated blood in leukocytes, plasma, erythrocytes and platelets, and analyzed the bactericidal power of each fraction and their combinations using a factorial design. We found that erythrocytes, but not platelets, participated and showed by flow cytometry that mycobacteria physically associated with erythrocytes. We propose that in exposed healthy individuals that show 'early clearance' of the mycobacteria, the innate response is predominantly humoral, probably through the effect of antimicrobial peptides and proteins.
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Affiliation(s)
| | - José Manuel Guerra-Laso
- Servicio de Medicina Interna, Complejo Asistencial Universitario de León, (CAULE), León, Spain
| | - Eduardo López-Fidalgo
- Unidad de Investigación, Complejo Asistencial Universitario de León (CAULE), León, Spain
| | - Cristina Diez-Tascón
- Servicio de Anatomía Patológica, Complejo Asistencial Universitario de León (CAULE), León, Spain Institute of Biomedicine (IBIOMED), Universidad de León, León, Spain
| | - Silvia García-García
- Servicio de Neumología, Complejo Asistencial Universitario de León (CAULE), León, Spain
| | - Sara Blanco-Conde
- Servicio de Análisis Clínicos, Complejo Asistencial Universitario de León (CAULE), León, Spain
| | - Octavio Miguel Rivero-Lezcano
- Unidad de Investigación, Complejo Asistencial Universitario de León (CAULE), León, Spain Institute of Biomedicine (IBIOMED), Universidad de León, León, Spain Fundación Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), León, Spain
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29
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Gallage S, Katagiri T, Endo M, Futami K, Endo M, Maita M. Influence of moderate hypoxia on vaccine efficacy against Vibrio anguillarum in Oreochromis niloticus (Nile tilapia). FISH & SHELLFISH IMMUNOLOGY 2016; 51:271-281. [PMID: 26915308 DOI: 10.1016/j.fsi.2016.02.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/18/2016] [Accepted: 02/18/2016] [Indexed: 06/05/2023]
Abstract
Hypoxia is known as a potential immunomodulator in fish. This study therefore assesses the impact of chronic, moderate hypoxia on vaccine efficacy in Oreochromis niloticus. Serum antibody titer was used as a surrogate marker to detect vaccine efficacy. The fish were acclimatized to either moderate hypoxia (55 ± 5% DO) or normoxia (85 ± 5%DO) and immunized with formalin inactivated Vibrio anguillarum. Significantly, a higher antibody titer was found in normoxic fish than in moderate hypoxia. The normoxic group titer peaked at 14th dpv (days post vaccination) while the moderate hypoxic group peaked at 21st or 28th dpv. The absolute blood lymphocyte counts and serum bactericidal activities against V. anguillarum were significantly higher in normoxic fish. Serum killing of V. anguillarum appeared to be mainly via antibody-dependent classical complement pathway. Furthermore, the first week following vaccination appears critical for antibody production. This view was further supported by results obtained from gene expression assay, where the transcription level of all the detected immune related genes (IgM, IL-1 β, TCR-β, MHC-II β), except B cell activating factor, were significantly suppressed following exposure to moderate hypoxia. The overall results highlight that even though moderate hypoxia is not easily detectable in Oreochromis niloticus, it negatively affects antibody production by suppressing and delaying antibody response, ultimately affecting vaccine efficacy.
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Affiliation(s)
- Sanchala Gallage
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Takayuki Katagiri
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Makoto Endo
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Kunihiko Futami
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Masato Endo
- Laboratory of Aquaculture, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
| | - Masashi Maita
- Laboratory of Fish Health Management, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
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Vivas-Alegre S, Fernández-Natal I, López-Fidalgo E, Rivero-Lezcano OM. Preparation of inocula for experimental infection of blood with Streptococcus pneumoniae. MethodsX 2015; 2:463-8. [PMID: 26844211 PMCID: PMC4688400 DOI: 10.1016/j.mex.2015.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 11/04/2015] [Indexed: 11/18/2022] Open
Abstract
Experimental infections of either cells or animals require the preparation of good quality inocula. Unfortunately, the important pulmonary pathogen Streptococcus pneumoniae is a fastidious microorganism that suffers an autolysis process when cultured in vitro. Supplementation of Todd–Hewitt broth with a biological buffer (20 mM Tris–HCl, pH = 7.8) promotes a six hours delay in the beginning of the autolysis process. Additional improvements include washing bacteria before freezing, avoiding manipulations after thawing, and the use of glycerol (<18%) as a cryoprotectant, instead of reagents like skimmed milk that may affect cell cultures. With the proposed protocol >70% of the frozen bacteria was viable after 28 weeks at −80 °C, and aliquots were highly homogeneous. We have tested their utility in a whole blood infection model and have found that human plasma exhibits a higher microbicidal activity than whole blood, a result that we have not found previously reported. Additionally, we have also observed significant variations in the antimicrobial activity against different strains, which might be related to their virulence.Media culture buffering extends S. pneumoniae viability for 6 h. Washing before freezing of single use aliquots minimizes manipulation after thawing. Experimental infection with the frozen inocula has shown that plasma has higher bactericidal activity than blood.
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Affiliation(s)
- Santiago Vivas-Alegre
- Servicio de Digestivo, Hospital de León, Altos de Nava s/n, 24008 León, Spain; Institute of Biomedicine (IBIOMED), University of León, León, Spain
| | | | | | - Octavio Miguel Rivero-Lezcano
- Institute of Biomedicine (IBIOMED), University of León, León, Spain; Unidad de Investigación, Hospital de León, Altos de Nava s/n, 24008 León, Spain; Fundación Instituto de Estudios de Ciencias de la Salud de Castilla y León, Spain
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Activation of endogenous anti-inflammatory mediator cyclic AMP attenuates acute pyelonephritis in mice induced by uropathogenic Escherichia coli. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:472-84. [PMID: 25478807 PMCID: PMC4305187 DOI: 10.1016/j.ajpath.2014.10.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/30/2014] [Accepted: 10/21/2014] [Indexed: 12/19/2022]
Abstract
The pathogenesis of pyelonephritis caused by uropathogenic Escherichia coli (UPEC) is not well understood. Here, we show that besides UPEC virulence, the severity of the host innate immune response and invasion of renal epithelial cells are important pathogenic factors. Activation of endogenous anti-inflammatory mediator cAMP significantly attenuated acute pyelonephritis in mice induced by UPEC. Administration of forskolin (a potent elevator of intracellular cAMP) reduced kidney infection (ie, bacterial load, tissue destruction); this was associated with attenuated local inflammation, as evidenced by the reduction of renal production of proinflammatory mediators, renal infiltration of inflammatory cells, and renal myeloperoxidase activity. In primary cell culture systems, forskolin not only down-regulated UPEC-stimulated production of proinflammatory mediators by renal tubular epithelial cells and inflammatory cells (eg, monocyte/macrophages) but also reduced bacterial internalization by renal tubular epithelial cells. Our findings clearly indicate that activation of endogenous anti-inflammatory mediator cAMP is beneficial for controlling UPEC-mediated acute pyelonephritis in mice. The beneficial effect can be explained at least in part by limiting excessive inflammatory responses through acting on both renal tubular epithelial cells and inflammatory cells and by inhibiting bacteria invasion of renal tubular epithelial cells.
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Gupta P, Gupta RK, Harjai K. Quorum sensing signal molecules produced by Pseudomonas aeruginosa cause inflammation and escape host factors in murine model of urinary tract infection. Inflammation 2014; 36:1153-9. [PMID: 23636638 DOI: 10.1007/s10753-013-9650-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Quorum sensing (QS) is well established for its role in pathogenesis of various infections of Pseudomonas aeruginosa. However, its role in local tissue damage during urinary tract infection (UTI) is not yet fully established. To have insight in this, the present study was planned. UTI was established in mice using standard strain PAO1 and its isogenic QS mutant JP2. One group was challenged only with QS signals. Damage was assessed in terms of histopathology and pathology markers, malondialdehyde (MDA) and reactive nitrogen intermediates (RNI). Effect on pathogen motility, uroepithelial adhesion, and host serum sensitivity was also ascertained. PAO1-infected mice showed severe inflammation and tissue destruction, while mice infected with JP2 showed no significant destruction. JP2 was also unable to mount any tissue pathology markers, MDA and RNI, whereas PAO1 showed significantly higher levels of these two. Presence of only QS signals also showed considerable renal pathology. Strain JP2 also showed less motility, reduced uroepithelial cell adhesion, and increased serum sensitivity. Result highlights that QS signals induce local tissue pathology along with interference of host protective mechanisms during UTI.
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Affiliation(s)
- Parul Gupta
- Department of Microbiology, BMS Block, Panjab University, Chandigarh, India, 160014
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Serum bactericidal assays to evaluate typhoidal and nontyphoidal Salmonella vaccines. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:712-21. [PMID: 24623629 DOI: 10.1128/cvi.00115-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Invasive Salmonella infections for which improved or new vaccines are being developed include enteric fever caused by Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B and sepsis and meningitis in young children in sub-Saharan Africa caused by nontyphoidal Salmonella (NTS) serovars, particularly S. enterica serovars Typhimurium and Enteritidis. Assays are needed to measure functional antibodies elicited by the new vaccines to assess their immunogenicities and potential protective capacities. We developed in vitro assays to quantify serum bactericidal antibody (SBA) activity induced by S. Typhi, S. Paratyphi A, S. Typhimurium, and S. Enteritidis vaccines in preclinical studies. Complement from various sources was tested in assays designed to measure antibody-dependent complement-mediated killing. Serum from rabbits 3 to 4 weeks of age provided the best complement source compared to serum from pigs, goats, horses, bovine calves, or rabbits 8 to 12 weeks of age. For S. Enteritidis, S. Typhimurium, and S. Typhi SBA assays to be effective, bacteria had to be harvested at log phase. In contrast, S. Paratyphi A was equally susceptible to killing whether it was grown to the stationary or log phase. The typhoidal serovars were more susceptible to complement-mediated killing than were the nontyphoidal serovars. Lastly, the SBA endpoint titers correlated with serum IgG anti-lipopolysaccharide (LPS) titers in mice immunized with mucosally administered S. Typhimurium, S. Enteritidis, and S. Paratyphi A but not S. Typhi live attenuated vaccines. The SBA assay described here is a useful tool for measuring functional antibodies elicited by Salmonella vaccine candidates.
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Serum complement enhances the responses of genotoxin- and oxidative stress-sensitive Escherichia coli bioreporters. Biosens Bioelectron 2013; 46:175-82. [PMID: 23545153 DOI: 10.1016/j.bios.2013.02.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/27/2012] [Accepted: 02/19/2013] [Indexed: 11/21/2022]
Abstract
Bacterial bioreporters are limited in their abilities to detect large polar molecules due to their membrane selectivity. In this study, the activity of serum complement was used to bypass this undesired selectivity. Initially, the serum complement activity was assessed using the responses of a bacterial bioreporter harboring a recA::luxCDABE transcriptional fusion when exposed to the chemotherapy drug, mitomycin C (MMC). Using 50 °C-treated serum, the limit of detection for this bacterial sensor was lowered by nearly 450-fold, from 31 μg/L to 0.07 μg/L MMC. Real-time quantitative PCR demonstrated that serum-treated cultures responded more strongly to 100 μg/L MMC, with 3.1-fold higher recA expression levels. Subsequent experiments with other bioreporter strains also found enhanced sensitivities and responses. Finally, combining each of the above findings, tests were performed to demonstrate the potential application of the recA::luxCDABE bioreporter within a lab-on-a-CD platform as a point-of-care diagnostic to measure chemotherapeutic drug concentrations within blood.
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Nayar R, Shukla I, Ali SM. Evaluation of the virulence markers in the clinical isolates of citrobacter species: the first report from India. J Clin Diagn Res 2013; 7:1031-4. [PMID: 23905096 DOI: 10.7860/jcdr/2013/5422.3073] [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: 01/16/2013] [Accepted: 04/18/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Citrobacter, a gram negative bacillus, is emerging as one of the major pathogens in hospital settings, with a potential to cause serious infections. Virulence markers are the factors which enhance the survival ability of the micro-organisms. Among the gram negative bacilli, these have been extensively studied in Escherichia coli. To the best of our knowledge as per internet search, we report that this study has been done for the first time in India on Citrobacter. AIMS An investigation was done to determine the ability of Citrobacter in producing virulence markers like the ability to survive the serum bactericidal activity, the resistance to the intracellular killing in the Polymorphonuclear Leucocytes (PMNLs) and the Cell Surface Hydrophobicity (CSH). SETTINGS AND DESIGN This prospective study was conducted in the Department of Microbiology of a tertiary care hospital in Aligarh, India, for a period of one year and six months. MATERIAL AND METHODS A total of 105 clinical isolates and 20 control isolates from healthy subjects were identified as having Citrobacter spp. by using standard biochemical tests and they were studied for the presence of virulence markers like the ability to survive the serum bactericidal activity, the resistance to the intracellular killing in the Polymorphonuclear Leucocytes (PMNLs) and the cell surface hydrophobicity. The statistical analysis which was used: The standard deviations and the p-values were calculated for comparison. RESULTS Out of the 105 clinical isolates of Citrobacter which were studied, 86.6% isolates were resistant to 100% serum after 180 minutes of incubation and intracellular killing in PMNL was demonstrated in 17% strains. The Salt Aggregation Test (SAT) for the cell surface hydrophobicity was positive in 17.1% strains at different concentrations of ammonium sulphate. The presence of more than one virulence marker was present in 71.4% of the clinical isolates while in the control isolates. CONCLUSIONS The presence of the virulence markers in Citrobacter demonstrated its pathogenic potential. Its invasiveness and ability to disseminate can be studied by identifying these markers.
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Affiliation(s)
- Ritu Nayar
- Senior Resident, Department of Microbiology, Dr Baba Saheb Ambedkar Hospital , Rohini, Delhi-85, India
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Liu Y, Bartlett JA, Di ME, Bomberger JM, Chan YR, Gakhar L, Mallampalli RK, McCray PB, Di YP. SPLUNC1/BPIFA1 contributes to pulmonary host defense against Klebsiella pneumoniae respiratory infection. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1519-31. [PMID: 23499554 DOI: 10.1016/j.ajpath.2013.01.050] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 01/10/2013] [Accepted: 01/14/2013] [Indexed: 12/12/2022]
Abstract
Epithelial host defense proteins comprise a critical component of the pulmonary innate immune response to infection. The short palate, lung, nasal epithelium clone (PLUNC) 1 (SPLUNC1) protein is a member of the bactericidal/permeability-increasing (BPI) fold-containing (BPIF) protein family, sharing structural similarities with BPI-like proteins. SPLUNC1 is a 25 kDa secretory protein that is expressed in nasal, oropharyngeal, and lung epithelia, and has been implicated in airway host defense against Pseudomonas aeruginosa and other organisms. SPLUNC1 is reported to have surfactant properties, which may contribute to anti-biofilm defenses. The objective of this study was to assess the importance of SPLUNC1 surfactant activity in airway epithelial secretions and to explore its biological relevance in the context of a bacterial infection model. Using cultured airway epithelia, we confirmed that SPLUNC1 is critically important for maintenance of low surface tension in airway fluids. Furthermore, we demonstrated that recombinant SPLUNC1 (rSPLUNC1) significantly inhibited Klebsiella pneumoniae biofilm formation on airway epithelia. We subsequently found that Splunc1(-/-) mice were significantly more susceptible to infection with K. pneumoniae, confirming the likely in vivo relevance of this anti-biofilm effect. Our data indicate that SPLUNC1 is a crucial component of mucosal innate immune defense against pulmonary infection by a relevant airway pathogen, and provide further support for the novel hypothesis that SPLUNC1 protein prevents bacterial biofilm formation through its ability to modulate surface tension of airway fluids.
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Affiliation(s)
- Yang Liu
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
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Schwizer S, Tasara T, Zurfluh K, Stephan R, Lehner A. Identification of genes involved in serum tolerance in the clinical strain Cronobacter sakazakii ES5. BMC Microbiol 2013; 13:38. [PMID: 23414256 PMCID: PMC3621496 DOI: 10.1186/1471-2180-13-38] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/14/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cronobacter spp. are opportunistic pathogens that can cause septicemia and infections of the central nervous system primarily in premature, low-birth weight and/or immune-compromised neonates. Serum resistance is a crucial virulence factor for the development of systemic infections, including bacteremia. It was the aim of the current study to identify genes involved in serum tolerance in a selected Cronobacter sakazakii strain of clinical origin. RESULTS Screening of 2749 random transposon knock out mutants of a C. sakazakii ES 5 library for modified serum tolerance (compared to wild type) revealed 10 mutants showing significantly increased/reduced resistance to serum killing. Identification of the affected sites in mutants displaying reduced serum resistance revealed genes encoding for surface and membrane proteins as well as regulatory elements or chaperones. By this approach, the involvement of the yet undescribed Wzy_C superfamily domain containing coding region in serum tolerance was observed and experimentally confirmed. Additionally, knock out mutants with enhanced serum tolerance were observed. Examination of respective transposon insertion loci revealed regulatory (repressor) elements, coding regions for chaperones and efflux systems as well as the coding region for the protein YbaJ. Real time expression analysis experiments revealed, that knock out of the gene for this protein negatively affects the expression of the fimA gene, which is a key structural component of the formation of fimbriae. Fimbriae are structures of high immunogenic potential and it is likely that absence/truncation of the ybaJ gene resulted in a non-fimbriated phenotype accounting for the enhanced survival of this mutant in human serum. CONCLUSION By using a transposon knock out approach we were able to identify genes involved in both increased and reduced serum tolerance in Cronobacter sakazakii ES5. This study reveals first insights in the complex nature of serum tolerance of Cronobacter spp.
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Affiliation(s)
- Sarah Schwizer
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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38
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Sayeed S, Nistico L, St Croix C, Di YP. Multifunctional role of human SPLUNC1 in Pseudomonas aeruginosa infection. Infect Immun 2013; 81:285-91. [PMID: 23132494 PMCID: PMC3536124 DOI: 10.1128/iai.00500-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 10/24/2012] [Indexed: 12/14/2022] Open
Abstract
The human short PLUNC1 (SPLUNC1) protein has been identified as a component of the pulmonary antimicrobial response based on its structural similarity to the bactericidal/permeability-increasing (BPI) protein. Using a genetically modified mouse model, we recently verified the antimicrobial activity of SPLUNC1 against Pseudomonas aeruginosa in vivo. To further define the mechanism of epithelial SPLUNC1-mediated antibacterial action, we carried out studies to determine how SPLUNC1 protects the host from acute respiratory infections. P. aeruginosa treated with recombinant human SPLUNC1 protein showed decreased growth in vitro. This antibacterial activity was due to growth inhibition, as a consequence of a SPLUNC1-induced increase in bacterial cell permeability. Removal of SPLUNC1 allowed the recovery of P. aeruginosa and suggested no permanent cell injury or direct killing of bacteria. Further investigation showed coating of bacterial cells by SPLUNC1. We suggest that this "bacterial cell coating" is necessary for the bacteriostatic function of SPLUNC1. Additionally, we demonstrated a novel role for SPLUNC1 as a chemoattractant that facilitated migration of macrophages and neutrophils. Taking the findings together, we propose synergistic roles for human SPLUNC1 as an antibacterial agent with bacteriostatic and chemotactic activities.
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Affiliation(s)
- Sameera Sayeed
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Laura Nistico
- Allegheny Singer Research Institute, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Claudette St Croix
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Y. Peter Di
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Role of lysozyme inhibitors in the virulence of avian pathogenic Escherichia coli. PLoS One 2012; 7:e45954. [PMID: 23049900 PMCID: PMC3458809 DOI: 10.1371/journal.pone.0045954] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/23/2012] [Indexed: 11/19/2022] Open
Abstract
Lysozymes are key effectors of the animal innate immunity system that kill bacteria by hydrolyzing peptidoglycan, their major cell wall constituent. Recently, specific inhibitors of the three major lysozyme families occuring in the animal kingdom (c-, g- and i-type) have been discovered in Gram-negative bacteria, and it has been proposed that these may help bacteria to evade lysozyme mediated lysis during interaction with an animal host. Escherichia coli produces two inhibitors that are specific for c-type lysozyme (Ivy, Inhibitor of vertebrate lysozyme; MliC, membrane bound lysozyme inhibitor of c-type lysozyme), and one specific for g-type lysozyme (PliG, periplasmic lysozyme inhibitor of g-type lysozyme). Here, we investigated the role of these lysozyme inhibitors in virulence of Avian Pathogenic E. coli (APEC) using a serum resistance test and a subcutaneous chicken infection model. Knock-out of mliC caused a strong reduction in serum resistance and in in vivo virulence that could be fully restored by genetic complementation, whereas ivy and pliG could be knocked out without effect on serum resistance and virulence. This is the first in vivo evidence for the involvement of lysozyme inhibitors in bacterial virulence. Remarkably, the virulence of a ivy mliC double knock-out strain was restored to almost wild-type level, and this strain also had a substantial residual periplasmic lysozyme inhibitory activity that was higher than that of the single knock-out strains. This suggests the existence of an additional periplasmic lysozyme inhibitor in this strain, and indicates a regulatory interaction in the expression of the different inhibitors.
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Atosuo JT, Lilius EM. The real-time-based assessment of the microbial killing by the antimicrobial compounds of neutrophils. ScientificWorldJournal 2011; 11:2382-90. [PMID: 22194669 PMCID: PMC3236378 DOI: 10.1100/2011/376278] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 11/03/2011] [Indexed: 11/24/2022] Open
Abstract
A recombinant Escherichia coli K-12 strain, transformed with a modified bacterial luciferase gene (luxABCDE) from Photorhabdus luminescens, was constructed in order to monitor the activity of various antimicrobial agents on a real-time basis. This E. coli-lux emitted, without any addition of substrate, constitutive bioluminescence (BL), which correlated to the number of viable bacterial cells. The decrease in BL signal correlated to the number of killed bacterial cells. Antimicrobial activity of hydrogen peroxide (H(2)O(2)) and myeloperoxidase (MPO) was assessed. In high concentrations, H(2)O(2) alone had a bacteriocidic function and MPO enhanced this killing by forming hypochlorous acid (HOCl). Taurine, the known HOCl scavenger, blocked the killing by MPO. When E. coli-lux was incubated with neutrophils, similar killing kinetics was recorded as in H(2)O(2)/MPO experiments. The opsonization of bacteria enhanced the killing, and the maximum rate of the MPO release from lysosomes coincided with the onset of the killing.
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Affiliation(s)
- J T Atosuo
- Laboratory of Immunochemistry, Department of Biochemistry and Food Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland.
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Ranjan KP, Ranjan N, Chakraborty A, Arora DR. An approach to uropathogenic Escherichia coli in urinary tract infections. J Lab Physicians 2011; 2:70-3. [PMID: 21346899 PMCID: PMC3040084 DOI: 10.4103/0974-2727.72152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose: To study the occurrence and characterization of Uropathogenic Escherichia Coli (UPEC) in cases with urinary tract infections. Materials and Methods: A total of 220 symptomatic cases from urinary tract infections and 50 stool samples from apparently healthy individuals were included. The colonies identified as Escherichia Coli were screened for virulence factors, that is, hemolysin, Mannose Resistant and Mannose Sensitive Hemagglutination (MRHA, MSHA), Cell surface hydrophobicity, and Serum resistance. Results: Among the 220 cases 91 (41.36%) were hemolytic, 68 (30.90%) showed MRHA, 58 (26.36%) were cell surface hydrophobicity positive, and 72 (32.72%) were serum-resistant. In 50 controls, three (6%) were hemolytic, six (12%) showed MRHA, nine (18%) showed cell surface hydrophobicity, and 12 (24%) were serum-resistant. The difference between cases and controls for hemolysis and MRHA were significant (P<0.001 and P<0.01, respectively). A total of 14 atypical E. coli were isolated from the urine and all showed the presence of one or the other virulence markers. Out of the 18 mucoid E.coli isolated, 10 were serum-resistant. Conclusions: The present study revealed that out of 220 urinary isolates, 151 could be labeled as UPEC.
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Affiliation(s)
- K Prabhat Ranjan
- Department of Microbiology, Pt. B D Sharma Postgraduate Institute of Medical Sciences, Rohtak, Haryana, India
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Bugla-Płoskońska G, Korzeniowska-Kowal A, Guz-Regner K. Reptiles as a source of Salmonella O48--clinically important bacteria for children: the relationship between resistance to normal cord serum and outer membrane protein patterns. MICROBIAL ECOLOGY 2011; 61:41-51. [PMID: 20480364 DOI: 10.1007/s00248-010-9677-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 04/12/2010] [Indexed: 05/29/2023]
Abstract
Bacteria of the Salmonella O48 somatic antigen group are clinically important strains causing intestinal dysfunction and diarrhoea, especially in children. The susceptibility of Salmonella O48 strains containing sialic acid (N-acetylneuraminic acid (NeuAc)) in lipopolysaccharide (LPS) to the bactericidal action of normal cord serum (NCS) was determined. The authors' previous results published in Microbial Ecology in 2010 indicated that neither the presence of NeuAc in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of normal human serum (NHS), and that the presence of NeuAc in the LPS structure is not sufficient to block the activation of the alternative pathway of complement in NHS. The current results showed that the tested strains showed various sensitivities also to the bactericidal action of NCS. The authors postulate that the presence of certain outer membrane proteins (OMPs) are characteristic of the resistant and sensitive phenotypes of Salmonella O48 strains. To establish a possible relationship between resistance to NCS and OMPs band patterns, ten Salmonella O48 strains were studied as follows: susceptibility to the bactericidal effect of NCS, the mechanisms of NCS activation and OMP band patterns obtained by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.
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Affiliation(s)
- Gabriela Bugla-Płoskońska
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63/77, 51-148, Wrocław, Poland.
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Bugla-Płoskońska G, Rybka J, Futoma-Kołoch B, Cisowska A, Gamian A, Doroszkiewicz W. Sialic acid-containing lipopolysaccharides of Salmonella O48 strains--potential role in camouflage and susceptibility to the bactericidal effect of normal human serum. MICROBIAL ECOLOGY 2010; 59:601-613. [PMID: 19844648 DOI: 10.1007/s00248-009-9600-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 10/03/2009] [Indexed: 05/28/2023]
Abstract
Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components (molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable.
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Affiliation(s)
- Gabriela Bugla-Płoskońska
- Department of Microbiology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63/77, 51-148 Wrocław, Poland.
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Ramos NL, Saayman ML, Chapman TA, Tucker JR, Smith HV, Faoagali J, Chin JC, Brauner A, Katouli M. Genetic relatedness and virulence gene profiles of Escherichia coli strains isolated from septicaemic and uroseptic patients. Eur J Clin Microbiol Infect Dis 2009; 29:15-23. [PMID: 19763642 DOI: 10.1007/s10096-009-0809-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 08/08/2009] [Indexed: 10/20/2022]
Abstract
We investigated the relationship between clonality and virulence factors (VFs) of a collection of Escherichia coli strains isolated from septicaemic and uroseptic patients with respect to their origin of translocation. Forty septicaemic and 30 uroseptic strains of E. coli were tested for their phylogenetic groupings, genetic relatedness using randomly amplified polymorphic DNA (RAPD), biochemical fingerprinting method (biochemical phenotypes [BPTs]), adherence to HT-29 cells and the presence of 56 E. coli VF genes. Strains belonging to phylogenetic groups B2 and D constituted 93% of all strains. Fifty-four (77%) strains belonged to two major BPT/RAPD clusters (A and B), with cluster A carrying significantly (P = 0.0099) more uroseptic strains. The degree of adhesion to HT-29 cells of uroseptic strains was significantly (P = 0.0012) greater than that of septicaemic strains. Of the 56 VF genes tested, pap genes was the only group that were found significantly (P < 0.0001) more often among uroseptic isolates. Phylogenetic group B2 contained a significantly higher number of strains carrying pap genes than those in group D. We conclude that uroseptic E. coli are clonally different from septicaemic strains, carry more pap genes and predominantly adhere more to the HT-29 cell model of the gut.
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Affiliation(s)
- N L Ramos
- Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore, DC, Queensland, Australia
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Transcriptional and translational analysis of biofilm determinants of Aggregatibacter actinomycetemcomitans in response to environmental perturbation. Infect Immun 2009; 77:2896-907. [PMID: 19433550 DOI: 10.1128/iai.00126-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Fimbriae, lipopolysaccharide (LPS), and extracellular polymeric substance (EPS) all contribute to biofilm formation by the periodontopathogen Aggregatibacter actinomycetemcomitans. To understand how individual biofilm determinants respond to changing environmental conditions, the transcription of genes responsible for fimbria, LPS, and EPS production, as well as the translation of these components, was determined in rough (Rv) and isogenic smooth (Sv) variants of A. actinomycetemcomitans cultured in half-strength and full-strength culture medium under anaerobic or aerobic conditions, and in iron-supplemented and iron-chelated medium. The transcription of tadV (fimbrial assembly), pgaC (extracellular polysaccharide synthesis), and orf8 or rmlB (lipopolysaccharide synthesis) was measured by real-time PCR. The amounts of fimbriae, LPS, and EPS were also estimated from stained sodium dodecyl sulfate-polyacrylamide gels and verified by Western blotting and enzyme-linked immunoadsorbent assay using specific antibodies. Each gene was significantly upregulated in the Rv compared to in the Sv. The transcription of fimbrial, LPS, and EPS genes in the Rv was increased approximately twofold in cells cultured in full-strength medium under anaerobic conditions compared to that in cells cultured under aerobic conditions. Under anaerobic conditions, the transcription of fimbrial and EPS enzymes was elevated in both Rv and Sv cells cultured in half-strength medium, compared to that in full-strength medium. Iron chelation also increased the transcription and translation of all biofilm determinants compared to their expression with iron supplementation, yet the quantity of biofilm was not significantly changed by any environmental perturbation except iron limitation. Thus, anaerobic conditions, nutrient stress, and iron limitation each upregulate known biofilm determinants of A. actinomycetemcomitans to contribute to biofilm formation.
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Li K, Zhou W, Hong Y, Sacks SH, Sheerin NS. Synergy between type 1 fimbriae expression and C3 opsonisation increases internalisation of E. coli by human tubular epithelial cells. BMC Microbiol 2009; 9:64. [PMID: 19335887 PMCID: PMC2670304 DOI: 10.1186/1471-2180-9-64] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 03/31/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial infection of the urinary tract is a common clinical problem with E. coli being the most common urinary pathogen. Bacterial uptake into epithelial cells is increasingly recognised as an important feature of infection. Bacterial virulence factors, especially fimbrial adhesins, have been conclusively shown to promote host cell invasion. Our recent study reported that C3 opsonisation markedly increases the ability of E. coli strain J96 to internalise into human proximal tubular epithelial cells via CD46, a complement regulatory protein expressed on host cell membrane. In this study, we further assessed whether C3-dependent internalisation by human tubular epithelial cells is a general feature of uropathogenic E. coli and investigated features of the bacterial phenotype that may account for any heterogeneity. RESULTS In 31 clinical isolates of E. coli tested, C3-dependent internalisation was evident in 10 isolates. Type 1 fimbriae mediated-binding is essential for C3-dependent internalisation as shown by phenotypic association, type 1 fimbrial blockade with soluble ligand (mannose) and by assessment of a type 1 fimbrial mutant. CONCLUSION we propose that efficient internalisation of uropathogenic E. coli by the human urinary tract depends on co-operation between type 1 fimbriae-mediated adhesion and C3 receptor -ligand interaction.
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Affiliation(s)
- Ke Li
- Complement Laboratory, Medical Research Council (MRC) Centre for Transplantation, Guy's Hospital, King's College London, London, UK.
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Role of the lysozyme inhibitor Ivy in growth or survival of Escherichia coli and Pseudomonas aeruginosa bacteria in hen egg white and in human saliva and breast milk. Appl Environ Microbiol 2008; 74:4434-9. [PMID: 18515493 DOI: 10.1128/aem.00589-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ivy is a lysozyme inhibitor that protects Escherichia coli against lysozyme-mediated cell wall hydrolysis when the outer membrane is permeabilized by mutation or by chemical or physical stress. In the current work, we have investigated whether Ivy is necessary for the survival or growth of E. coli MG1655 and Pseudomonas aeruginosa PAO1 in hen egg white and in human saliva and breast milk, which are naturally rich in lysozyme and in membrane-permeabilizing components. Wild-type E. coli was able to grow in saliva and breast milk but showed partial inactivation in egg white. The knockout of Ivy did not affect growth in breast milk but slightly increased sensitivity to egg white and caused hypersensitivity to saliva, resulting in the complete inactivation of 10(4) CFU ml(-1) of bacteria within less than 5 hours. The depletion of lysozyme from saliva completely restored the ability of the ivy mutant to grow like the parental strain. P. aeruginosa, in contrast, showed growth in all three substrates, which was not affected by the knockout of Ivy production. These results indicate that lysozyme inhibitors like Ivy promote bacterial survival or growth in particular lysozyme-rich secretions and suggest that they may promote the bacterial colonization of specific niches in the animal host.
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MacLennan CA, Gondwe EN, Msefula CL, Kingsley RA, Thomson NR, White SA, Goodall M, Pickard DJ, Graham SM, Dougan G, Hart CA, Molyneux ME, Drayson MT. The neglected role of antibody in protection against bacteremia caused by nontyphoidal strains of Salmonella in African children. J Clin Invest 2008; 118:1553-62. [PMID: 18357343 DOI: 10.1172/jci33998] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 02/13/2008] [Indexed: 11/17/2022] Open
Abstract
Nontyphoidal strains of Salmonella (NTS) are a common cause of bacteremia among African children. Cell-mediated immune responses control intracellular infection, but they do not protect against extracellular growth of NTS in the blood. We investigated whether antibody protects against NTS bacteremia in Malawian children, because we found this condition mainly occurs before 2 years of age, with relative sparing of infants younger than 4 months old. Sera from all healthy Malawian children tested aged more than 16 months contained anti-Salmonella antibody and successfully killed NTS. Killing was mediated by complement membrane attack complex and not augmented in the presence of blood leukocytes. Sera from most healthy children less than 16 months old lacked NTS-specific antibody, and sera lacking antibody did not kill NTS despite normal complement function. Addition of Salmonella-specific antibody, but not mannose-binding lectin, enabled NTS killing. All NTS strains tested had long-chain lipopolysaccharide and the rck gene, features that resist direct complement-mediated killing. Disruption of lipopolysaccharide biosynthesis enabled killing of NTS by serum lacking Salmonella-specific antibody. We conclude that Salmonella-specific antibody that overcomes the complement resistance of NTS develops by 2 years of life in Malawian children. This finding and the age-incidence of NTS bacteremia suggest that antibody protects against NTS bacteremia and support the development of vaccines against NTS that induce protective antibody.
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Affiliation(s)
- Calman A MacLennan
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi.
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Lipopolysaccharide O-antigen chain length regulation in Pseudomonas aeruginosa serogroup O11 strain PA103. J Bacteriol 2007; 190:2709-16. [PMID: 18065548 DOI: 10.1128/jb.01646-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Wzz proteins are important for determining the length of the O-antigen side chain attached to lipopolysaccharide (LPS). Several bacteria, including Pseudomonas aeruginosa strain PAO1 (serogroup O5), produce two such proteins responsible for the preference of two different chain lengths on the surface. Our group has previously identified one wzz gene (wzz1) within the O-antigen locus of P. aeruginosa strain PA103 (serogroup O11). In this study we have identified the second wzz gene (wzz2), located in the same region of the genome and with 92% similarity to PAO1's wzz2 gene. Mutations were generated in both wzz genes by interruption with antibiotic resistance cassettes, and the effects of these mutations were characterized. Wild-type PA103 prefers two O-antigen chain lengths, referred to as long and very long. The expression of the long O-antigen chain length was reduced in the wzz1 mutant, indicating the Wzz1 protein is important for this chain length preference. The wzz2 mutant, on the other hand, was missing O-antigens of the very long chain length, indicating the Wzz2 protein is responsible for the production of very long O-antigen. The effects of the wzz mutations on virulence were also investigated. In both serum sensitivity assays and a mouse pneumonia model of infection, the wzz1 mutants exhibited greater defects in virulence compared to either wild-type PA103 or the wzz2 mutant, indicating the long chain length plays a greater role during these infectious processes.
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Abstract
ADP-l-glycero-d-manno-heptose 6-epimerase (HldD or AGME, formerly RfaD) catalyzes the interconversion of ADP-beta-d-glycero-d-manno-heptose (ADP-d,d-Hep) and ADP-beta-l-glycero-d-manno-heptose (ADP-l,d-Hep). The latter compound provides the heptose moiety that is used in lipopolysaccharide biosynthesis by Gram-negative bacteria. Several lines of evidence suggest that the enzyme uses a direct oxidation/reduction mechanism involving a tightly bound NADP+ cofactor. An initial oxidation at C-6'' gives a 6''-keto intermediate, and a subsequent reduction on the opposite face of the carbonyl group generates the epimeric product. The reorientation required for the nonstereoselective reduction could take place within a single active site, or it could involve the release of the intermediate and rebinding in an altered conformation. To distinguish between these possibilities, two isotopically labeled substrates (ADP-d,d-Hep) were prepared that contained 18O and 2H isotopes at C-7'' and C-6'', respectively. A crossover experiment was used to determine whether unlabeled or doubly labeled products were formed upon epimerization of a mixture of the two singly labeled compounds. After an initial epimeric equilibrium was reached, no crossover could be detected, indicating that intermediate release is not intrinsic to the overall mechanism. After extended incubation, however, scrambling of the labels could be detected, indicating that a low background rate of intermediate release does occur. To directly detect the release of the intermediate, the labeled compounds were independently epimerized in the presence of a ketone-trapping reagent, phenylhydrazine. The corresponding phenylhydrazones were identified by mass spectrometry, and the absence of any 2H isotope in the adduct obtained from the deuterated starting compound confirmed that the oxidation had occurred at C-6''.
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Affiliation(s)
- Alain Mayer
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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