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Yan J, Nielsen TB, Lu P, Talyansky Y, Slarve M, Reza H, Novakovic B, Netea MG, Keller AE, Warren T, DiGiandomenico A, Sellman BR, Luna BM, Spellberg B. A protein-free vaccine stimulates innate immunity and protects against nosocomial pathogens. Sci Transl Med 2023; 15:eadf9556. [PMID: 37792959 PMCID: PMC10947341 DOI: 10.1126/scitranslmed.adf9556] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 08/15/2023] [Indexed: 10/06/2023]
Abstract
Traditional vaccines are difficult to deploy against the diverse antimicrobial-resistant, nosocomial pathogens that cause health care-associated infections. We developed a protein-free vaccine composed of aluminum hydroxide, monophosphoryl lipid A, and fungal mannan that improved survival and reduced bacterial burden of mice with invasive blood or lung infections caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, extended-spectrum beta-lactamase-expressing Escherichia coli, and carbapenem-resistant strains of Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The vaccine also conferred protection against the fungi Rhizopus delemar and Candida albicans. Efficacy was apparent by 24 hours and lasted for up to 28 days after a single vaccine dose, with a second dose restoring efficacy. The vaccine acted through stimulation of the innate, rather than the adaptive, immune system, as demonstrated by efficacy in the absence of lymphocytes that were abrogated by macrophage depletion. A role for macrophages was further supported by the finding that vaccination induced macrophage epigenetic alterations that modulated phagocytosis and the inflammatory response to infection. Together, these data show that this protein-free vaccine is a promising strategy to prevent deadly antimicrobial-resistant health care-associated infections.
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Affiliation(s)
- Jun Yan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Travis B. Nielsen
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- UC San Diego School of Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Peggy Lu
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Yuli Talyansky
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Matt Slarve
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Hernan Reza
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Boris Novakovic
- Murdoch Children’s Research Institute and Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Parkville, VIC 3052, Australia
| | - Mihai G. Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
- Department of Immunology and Metabolism, Life and Medical Sciences Institute, University of Bonn, 53115 Bonn, Germany
| | - Ashley E. Keller
- AstraZeneca Inc., Early Vaccines and Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA
| | - Troy Warren
- AstraZeneca Inc., Early Vaccines and Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA
| | - Antonio DiGiandomenico
- AstraZeneca Inc., Early Vaccines and Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA
| | - Bret R. Sellman
- AstraZeneca Inc., Early Vaccines and Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA
| | - Brian M. Luna
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Brad Spellberg
- Los Angeles General Medical Center, Los Angeles, CA 90033, USA
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Nielsen TB, Yan J, Slarve M, Li R, Junge JA, Luna BM, Wilkinson I, Yerramalla U, Spellberg B. Development of a Bispecific Antibody Targeting Clinical Isolates of Acinetobacter baumannii. J Infect Dis 2023; 227:1042-1049. [PMID: 36617220 PMCID: PMC10319980 DOI: 10.1093/infdis/jiac499] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 12/16/2022] [Accepted: 01/05/2023] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND We previously reported developing 2 anticapsular monoclonal antibodies (mAbs) as a novel therapy for Acinetobacter baumannii infections. We sought to determine whether a bispecific mAb (bsAb) could improve avidity and efficacy while maximizing strain coverage in one molecule. METHODS Humanized mAb 65 was cloned into a single-chain variable fragment and attached to humanized mAb C8, combining their paratopes into a single bsAb (C73). We tested bsAb C73's strain coverage, binding affinity, ex vivo opsonic activity, and in vivo efficacy compared to each mAb alone and combined. RESULTS The bsAb demonstrated strain coverage, binding affinity, opsonization, and in vivo efficacy superior to either original mAb alone or combined. CONCLUSIONS A humanized bsAb targeting distinct A. baumannii capsule moieties enabled potent and effective coverage of disparate A. baumannii clinical isolates. The bsAb enhances feasibility of development by minimizing the number of components of a promising novel therapeutic for these difficult-to-treat infections.
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Affiliation(s)
- Travis B Nielsen
- Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA
- Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Maywood, Illinois, USA
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Jun Yan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Matthew Slarve
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Rachel Li
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Jason A Junge
- Translational Imaging Center, School of Engineering, University of Southern California, Los Angeles, California, USA
| | - Brian M Luna
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | | | | | - Brad Spellberg
- Los Angeles County + University of Southern California Medical Center, Los Angeles, California, USA
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3
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Phage-mimicking nanoagents for rapid depolymerase specificity screening against multidrug resistant bacteria. Biosens Bioelectron 2022; 213:114444. [PMID: 35691082 DOI: 10.1016/j.bios.2022.114444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 11/23/2022]
Abstract
With the rise of drug resistance, bacteriophages and bacteriophage-derived proteins may become an efficient successor to traditional antibiotics. While the enormous natural diversity of the phages allows matching virtually any bacteria, identification of the potentially life-saving phage is currently a tedious and time-consuming challenge that often cannot be performed within a reasonable time. Here we show a rapid 1-min bacteriophage screening assay based on specially constructed phage-mimicking nanoagents and surface plasmon resonance effect. Within the assay, a panel of phage-mimicking gold nanoparticles, possessing the specificity and enzymatic activity of a particular phage, is mixed with a suspension of the bacteria of interest. The spectral behaviour of the assay mix allows measurement of two critical parameters of the nanoagents and the corresponding bacteriophages: 1) direct assessment of their specificity due to convergence of the particles on the cell walls, and more importantly, 2) real-time evaluation of their enzymatic activity for the destruction of the cell capsule via detection of nanoagent detachment from the surface of bacteria. The proposed assay overcomes the current time limitations of the phage-bacteria matching procedures and thereby can facilitate faster development and adoption of phage-based therapies as a much-needed alternative to traditional antibiotics.
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Acacia Fiber Protects the Gut from Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli Colonization Enabled by Antibiotics. mSphere 2022; 7:e0007122. [PMID: 35582906 PMCID: PMC9241499 DOI: 10.1128/msphere.00071-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Novel approaches to combating antibiotic resistance are needed given the ever-continuing rise of antibiotic resistance and the scarce discovery of new antibiotics. Little is known about the colonization dynamics and the role of intrinsic plant-food characteristics in this process. We sought to determine whether plant fiber could alter colonization dynamics by antibiotic-resistant bacteria in the gut. We determined that ingestion of antibiotics in mice markedly enhanced gut colonization by a pathogenic extended-spectrum beta-lactamase-producing Escherichia coli strain of human origin, E. coli JJ1886 (ST131-H30Rx). Furthermore, ingestion of soluble acacia fiber before and after antibiotic exposure significantly reduced pathogenic E. coli colonization. 16S rRNA analysis and ex vivo cocultures demonstrated that fiber protected the microbiome by serving as a prebiotic, which induced native gut E. coli to inhibit pathogenic E. coli via colicin M. Fiber may be a useful prebiotic with which to administer antibiotics to protect human and livestock gut microbiomes against colonization from antibiotic-resistant, pathogenic bacteria. IMPORTANCE A One Health-based strategy-the concept that human health and animal health are interconnected with the environment-is necessary to determine the drivers of antibiotic resistance from food to the clinic. Moreover, humans can ingest antibiotic-resistant bacteria on food and asymptomatically, or "silently," carry such bacteria in the gut long before they develop an opportunistic extraintestinal infection. Here, we determined that fiber-rich foods, in particular acacia fiber, may be a new, promising, and inexpensive prebiotic to administer with antibiotics to protect the mammalian (i.e., human and livestock) gut against such colonization by antibiotic-resistant, pathogenic bacteria.
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5
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A host-directed macrocyclic peptide therapeutic for MDR gram negative bacterial infections. Sci Rep 2021; 11:23447. [PMID: 34873199 PMCID: PMC8648872 DOI: 10.1038/s41598-021-02619-y] [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: 09/22/2021] [Accepted: 11/18/2021] [Indexed: 01/26/2023] Open
Abstract
The emergence of infections by carbapenem resistant Enterobacteriaceae (CRE) pathogens has created an urgent public health threat, as carbapenems are among the drugs of last resort for infections caused by a growing fraction of multi-drug resistant (MDR) bacteria. There is global consensus that new preventive and therapeutic strategies are urgently needed to combat the growing problem of MDR bacterial infections. Here, we report on the efficacy of a novel macrocyclic peptide, minimized theta-defensin (MTD)-12813 in CRE sepsis. MTD12813 is a theta-defensin inspired cyclic peptide that is highly effective against CRE pathogens K. pneumoniae and E. coli in vivo. In mouse septicemia models, single dose administration of MTD12813 significantly enhanced survival by promoting rapid host-mediated bacterial clearance and by modulating pathologic cytokine responses, restoring immune homeostasis, and preventing lethal septic shock. The peptide lacks direct antibacterial activity in the presence of mouse serum or in peritoneal fluid, further evidence for its indirect antibacterial mode of action. MTD12813 is highly stable in biological matrices, resistant to bacterial proteases, and nontoxic to mice at dose levels 100 times the therapeutic dose level, properties which support further development of the peptide as a first in class anti-infective therapeutic.
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6
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Abstract
Background: Extremely drug-resistant (XDR) Acinetobacter baumannii is a notorious and frequently encountered pathogen demanding novel therapeutic interventions. An initial monoclonal antibody (MAb), C8, raised against A. baumannii capsule proved a highly effective treatment against a minority of clinical isolates. To overcome this limitation, we broadened coverage by developing a second antibody for use in a combination regimen. Methods: We sought to develop an additional anti-A. baumannii MAb through hybridoma technology by immunizing mice with sublethal inocula of virulent, XDR clinical isolates not bound by MAb C8. Results: We identified a new antibacterial MAb, 65, which bound to strains in a pattern distinct from and complementary to MAb C8. MAb 65 enhanced macrophage opsonophagocytosis of targeted strains and markedly improved survival in lethal bacteremic sepsis and aspiration pneumonia murine models of A. baumannii infection. MAb 65 was also synergistic with colistin, substantially enhancing protection compared to monotherapy. Treatment with MAb 65 significantly reduced blood bacterial density, ameliorated cytokine production (IL-1β, IL-6, IL-10, and TNF), and sepsis biomarkers. Conclusions: We describe a novel MAb targeting A. baumannii that broadens immunotherapeutic strain coverage, is highly potent and effective, and synergistically improves outcomes in combination with antibiotics.
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7
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Nielsen TB, Yan J, Luna BM, Talyansky Y, Slarve M, Bonomo RA, Spellberg B. Monoclonal antibody requires immunomodulation for efficacy against Acinetobacter baumannii infection. J Infect Dis 2021; 224:2133-2147. [PMID: 34036366 DOI: 10.1093/infdis/jiab265] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Monoclonal antibodies (MAbs) are gaining significant momentum as novel therapeutics for infections caused by antibiotic-resistant bacteria. We evaluated the mechanism by which anti-bacterial MAb therapy protects against Acinetobacter baumannii infections. Anti-capsular MAb enhanced macrophage opsonophagocytosis and rescued mice from lethal infections by harnessing complement, macrophages, and neutrophils, yet the degree of bacterial burden did not correlate with survival. Furthermore, MAb therapy reduced pro-inflammatory (IL-1β, IL-6, TNFα) and anti-inflammatory (IL-10) cytokines, which correlated inversely with survival. Although disrupting IL-10 abrogated the survival advantage conferred by the MAb, IL-10-knockout mice treated with MAb could still survive if TNFα production was suppressed directly (via anti-TNFα neutralizing antibody) or indirectly (via macrophage depletion). Thus, even for a MAb that enhances microbial clearance via opsonophagocytosis, clinical efficacy required modulation of pro- and anti-inflammatory cytokines. These findings may inform future MAb development targeting bacteria that trigger the sepsis cascade.
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Affiliation(s)
- Travis B Nielsen
- Stritch School of Medicine at Loyola University Chicago, Maywood, IL, 60153, United States.,Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Jun Yan
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Brian M Luna
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Yuli Talyansky
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Matthew Slarve
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Robert A Bonomo
- Department of Medicine, Pharmacology, and Molecular Biology and Microbiology, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, OH, 44120, United States
| | - Brad Spellberg
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
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8
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Luna B, Trebosc V, Lee B, Bakowski M, Ulhaq A, Yan J, Lu P, Cheng J, Nielsen T, Lim J, Ketphan W, Eoh H, McNamara C, Skandalis N, She R, Kemmer C, Lociuro S, Dale GE, Spellberg B. A nutrient-limited screen unmasks rifabutin hyperactivity for extensively drug-resistant Acinetobacter baumannii. Nat Microbiol 2020; 5:1134-1143. [PMID: 32514072 PMCID: PMC7483275 DOI: 10.1038/s41564-020-0737-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/10/2020] [Indexed: 11/09/2022]
Abstract
Industry screens of large chemical libraries have traditionally relied on rich media to ensure rapid bacterial growth in high-throughput testing. We used eukaryotic, nutrient-limited growth media in a compound screen that unmasked a previously unknown hyperactivity of the old antibiotic, rifabutin (RBT), against highly resistant Acinetobacter baumannii. In nutrient-limited, but not rich, media, RBT was 200-fold more potent than rifampin. RBT was also substantially more effective in vivo. The mechanism of enhanced efficacy was a Trojan horse-like import of RBT, but not rifampin, through fhuE, only in nutrient-limited conditions. These results are of fundamental importance to efforts to discover antibacterial agents.
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Affiliation(s)
- Brian Luna
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA.
| | | | - Bosul Lee
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | | | - Amber Ulhaq
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Jun Yan
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Peggy Lu
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Jiaqi Cheng
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Travis Nielsen
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Juhyeon Lim
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Warisa Ketphan
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Hyungjin Eoh
- Department of Molecular Microbiology and Immunology, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Case McNamara
- Calibr, Scripps Research Institute, La Jolla, CA, USA
| | - Nicholas Skandalis
- Department of Medicine, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Rosemary She
- Department of Pathology, USC Keck School of Medicine, Los Angeles, CA, USA
| | | | | | | | - Brad Spellberg
- Los Angeles County and University of Southern California Medical Center, Los Angeles, CA, USA.
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Luna BM, Yan J, Reyna Z, Moon E, Nielsen TB, Reza H, Lu P, Bonomo R, Louie A, Drusano G, Bulitta J, She R, Spellberg B. Natural history of Acinetobacter baumannii infection in mice. PLoS One 2019; 14:e0219824. [PMID: 31318907 PMCID: PMC6638954 DOI: 10.1371/journal.pone.0219824] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/03/2019] [Indexed: 01/30/2023] Open
Abstract
In 2017, the WHO identified Acinetobacter baumannii as the top priority for the development of new antibiotics. Despite the need for new antibiotics, there remains a lack of well validated preclinical tools for A. baumannii. Here, we characterize and validate a mouse model for A. baumannii translational research. Antibiotic sensitivity for meropenem, amikacin, and polymyxin b was determined by the broth microdilution MIC assay. LD100 inoculums, in both blood and lung infection models, were determined in male and female C3HeB/FeJ mice that were challenged with various A. baumannii clinical isolates. Blood (blood infection model) or blood and lung tissue (lung infection model) were collected from infected mice at 2 and 18 hours and the bacterial burden was determined by quantitative culture. Blood chemistry was analyzed using the iStat system. Cytokines (IL-1ß, TNF, IL-6, and IL-10) were measured in the blood and lung homogenate by ELISA assay. Lung sections (H&E stains) were scored by a pathologist. In the blood infection model, the cytokines and physiological data indicate that mice become moribund due to sepsis (low blood pH, falling bicarbonate, and a rising base deficit), whereas mice become moribund due to respiratory failure (low blood pH, rising bicarbonate, and a falling base deficit) in the oral aspiration pneumonia model. We also characterized the timing of changes in various clinical and biomarker endpoints, which can serve as a basis for future interventional studies. Susceptibility was generally similar across gender and infection route. However, we did observe that female mice were approximately 2-fold more sensitive to LAC-4 ColR in the blood infection model. We also observed that female mice were more than 10-fold more resistant to VA-AB41 in the oral aspiration pneumonia model. These results establish parameters to follow in order to assess efficacy of novel preventative and therapeutic approaches for these infections.
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Affiliation(s)
- Brian M. Luna
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- * E-mail:
| | - Jun Yan
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Zeferino Reyna
- Department of Pathology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Eugene Moon
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Travis B. Nielsen
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Hernan Reza
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Peggy Lu
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Robert Bonomo
- Departments of Medicine, Pharmacology, and Molecular Biology and Microbiology, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Arnold Louie
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, United States of America
| | - George Drusano
- Institute for Therapeutic Innovation, College of Medicine, University of Florida, Orlando, Florida, United States of America
| | - Jürgen Bulitta
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, United States of America
| | - Rosemary She
- Department of Pathology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
| | - Brad Spellberg
- Department of Medicine, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, California, United States of America
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10
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Nielsen TB, Yan J, Luna B, Spellberg B. Murine Oropharyngeal Aspiration Model of Ventilator-associated and Hospital-acquired Bacterial Pneumonia. J Vis Exp 2018. [PMID: 30010650 DOI: 10.3791/57672] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Murine infection models are critical for understanding disease pathogenesis and testing the efficacy of novel therapeutics designed to combat causative pathogens. Infectious pneumonia is among the most common infections presented by patients in the clinic and thus warrants an appropriate in vivo model. Typical pneumonia models use intranasal inoculation, which deposits excessive organisms outside the lung, causing off-target complications and symptoms, such as sinusitis, gastritis, enteritis, physical trauma, or microparticle misting to mimic aerosol spread more typical of viral, tuberculous, or fungal pneumonia. These models do not accurately reflect the pathogenesis of typical community- or healthcare-acquired bacterial pneumonia. In contrast, this murine model of oropharyngeal aspiration pneumonia mimics the droplet route in healthcare-acquired pneumonia. Inoculating 50 µL of the bacteria suspension into the oropharynx of anesthetized mice causes reflexive aspiration, which results in pneumonia. With this model, one can examine the pathogenesis of pneumonia-causing pathogens and new treatments to combat these diseases.
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Affiliation(s)
- Travis B Nielsen
- Department of Molecular Microbiology and Immunology, University of Southern California;
| | - Jun Yan
- Department of Molecular Microbiology and Immunology, University of Southern California
| | - Brian Luna
- Department of Molecular Microbiology and Immunology, University of Southern California
| | - Brad Spellberg
- Department of Molecular Microbiology and Immunology, University of Southern California; Division of Infectious Diseases, Department of Medicine, LAC+USC Medical Center
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11
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Nielsen TB, Pantapalangkoor P, Luna BM, Bruhn KW, Yan J, Dekitani K, Hsieh S, Yeshoua B, Pascual B, Vinogradov E, Hujer KM, Domitrovic TN, Bonomo RA, Russo TA, Lesczcyniecka M, Schneider T, Spellberg B. Monoclonal Antibody Protects Against Acinetobacter baumannii Infection by Enhancing Bacterial Clearance and Evading Sepsis. J Infect Dis 2017; 216:489-501. [PMID: 28931235 DOI: 10.1093/infdis/jix315] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 06/30/2017] [Indexed: 01/01/2023] Open
Abstract
Background Extremely drug-resistant (XDR) Acinetobacter baumannii is one of the most commonly encountered, highly resistant pathogens requiring novel therapeutic interventions. Methods We developed C8, a monoclonal antibody (mAb), by immunizing mice with sublethal inocula of a hypervirulent XDR clinical isolate. Results C8 targets capsular carbohydrate on the bacterial surface, enhancing opsonophagocytosis. Treating with a single dose of C8 as low as 0.5 μg/mouse (0.0167 mg/kg) markedly improved survival in lethal bacteremic sepsis and aspiration pneumonia models of XDR A. baumannii infection. C8 was also synergistic with colistin, substantially improving survival compared to monotherapy. Treatment with C8 significantly reduced blood bacterial density, cytokine production (tumor necrosis factor α, interleukin [IL] 6, IL-1β, and IL-10), and sepsis biomarkers. Serial in vitro passaging of A. baumannii in the presence of C8 did not cause loss of mAb binding to the bacteria, but did result in emergence of less-virulent mutants that were more susceptible to macrophage uptake. Finally, we developed a highly humanized variant of C8 that retains opsonophagocytic activity in murine and human macrophages and rescued mice from lethal infection. Conclusions We describe a promising and novel mAb as therapy for lethal, XDR A. baumannii infections, and demonstrate that it synergistically improves outcomes in combination with antibiotics.
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Affiliation(s)
- Travis B Nielsen
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Paul Pantapalangkoor
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Brian M Luna
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Kevin W Bruhn
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Jun Yan
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Ken Dekitani
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Sarah Hsieh
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Brandon Yeshoua
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | - Bryan Pascual
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
| | | | - Kristine M Hujer
- Louis Stokes Cleveland Veterans Affairs Medical Center.,Department of Medicine
| | | | - Robert A Bonomo
- Louis Stokes Cleveland Veterans Affairs Medical Center.,Department of Medicine.,Departments of Pharmacology, Molecular Biology and Microbiology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio
| | - Thomas A Russo
- Veterans Administration Western New York Healthcare System, and the Departments of Medicine and Microbiology and Immunology, and Witebsky Center for Microbial Pathogenesis, University at Buffalo-State University of New York, Buffalo, New York
| | | | | | - Brad Spellberg
- Department of Medicine and Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles
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Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges. Clin Microbiol Rev 2017; 30:409-447. [PMID: 27974412 DOI: 10.1128/cmr.00058-16] [Citation(s) in RCA: 616] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)-Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed.
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Abdelnasser SM, M Yahya SM, Mohamed WF, Asker MMS, Abu Shady HM, Mahmoud MG, Gadallah MA. Antitumor Exopolysaccharides Derived from Novel Marine Bacillus: Isolation, Characterization Aspect and Biological Activity. Asian Pac J Cancer Prev 2017; 18:1847-1854. [PMID: 28749119 PMCID: PMC5648389 DOI: 10.22034/apjcp.2017.18.7.1847] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Objective: Exopolysaccharides gained attention as new source for cancer treatment as recent treatments cause side
effects and multidrug resistance. Polysaccharides containing sulfur and uronic acids exhibited antioxidant activity, by
restoring cell redox regulation, thus inhibiting cell proliferation and cancer formation. Following this context, our study
was performed to assess the cytotoxic activity of exopolysaccharides produced by novel Egyptian marine bacterial
strains on HepG2 cells. Methods: Bacteria were isolated, purified and cultured through routine microbiological
techniques. 16S rRNA gene amplification and sequence analyses, Fourier Transform Infra-red (FTIR), Identification
of monosugars by HPLC molecular weight estimation, sulfur content determination and neutral red uptake assay were
utilized. Results: BLAST showed that the isolates were related to the Bacillus sp. FTIR analysis indicated that the
four EPSs under study contained sulfur as substituent functional group but with different percentage in each EPS.
The highest sulfur percentage (46%) appeared in the EPS-6 that was produced by Bacillus flexus isolated from the
Mediterranean Sea. HPLC showed that EPSs contained uronic acids which appeared as glucuronic and galacturonic acid
in the low molecular weight EPS-6 (4.296×104 g mol-1). Arabinose appeared besides the glucuronic and galacturonic
acid residues. EPS-6 showed the highest cytotoxicity, IC50 (218 μg ml-1) which could be correlated to the presence of
sulfure and uronic acids in its structure. Conclusion: The novel Firmicutes from the Egyptian saline habitat produced
EPSs of cytotoxic activity on hepatocellular carcinoma.
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Affiliation(s)
- Salma M Abdelnasser
- Department of Microbial Biotechnology, National Research Centre, Dokki, Giza, Egypt .
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Selectable Markers for Use in Genetic Manipulation of Extensively Drug-Resistant (XDR) Acinetobacter baumannii HUMC1. mSphere 2017; 2:mSphere00140-17. [PMID: 28497114 PMCID: PMC5422034 DOI: 10.1128/msphere.00140-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 04/06/2017] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains of Acinetobacter baumannii have frequently been characterized. The ability of A. baumannii to develop resistance to antibiotics is a key reason this organism has been difficult to study using genetic and molecular biology approaches. Here we report selectable markers that are not only useful but necessary for the selection of drug-resistant transformants in the setting of drug-resistant backgrounds. Use of these selectable markers can be applied to a variety of genetic and molecular techniques such as mutagenesis and transformation. These selectable markers will help promote genetic and molecular biology studies of otherwise onerous drug-resistant strains, while avoiding the generation of pathogenic organisms that are resistant to clinically relevant antibiotics. Acinetobacter baumannii is one of the most antibiotic-resistant pathogens in clinical medicine, and extensively drug-resistant (XDR) strains are commonly isolated from infected patients. Such XDR strains are already resistant to traditional selectable genetic markers, limiting the ability to conduct pathogenesis research by genetic disruption. Optimization of selectable markers is therefore critical for the advancement of fundamental molecular biology techniques to use in these strains. We screened 23 drugs that constitute a broad array of antibiotics spanning multiple drug classes against HUMC1, a highly virulent and XDR A. baumannii clinical blood and lung isolate. HUMC1 is resistant to all clinically useful antibiotics that are reported by the clinical microbiology laboratory, except for colistin. Ethical concerns about intentionally establishing pan-resistance, including to the last-line agent, colistin, in a clinical isolate made identification of other markers desirable. We screened additional antibiotics that are in clinical use and those that are useful only in a lab setting to identify selectable markers that were effective at selecting for transformants in vitro. We show that supraphysiological levels of tetracycline can overcome innate drug resistance displayed by this XDR strain. Last, we demonstrate that transformation of the tetA (tetracycline resistance) and Sh ble (zeocin resistance), but not pac (puromycin resistance), resistance cassettes allow for selection of drug-resistant transformants. These results make the genetic manipulation of XDR A. baumannii strains easily achieved. IMPORTANCE Multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains of Acinetobacter baumannii have frequently been characterized. The ability of A. baumannii to develop resistance to antibiotics is a key reason this organism has been difficult to study using genetic and molecular biology approaches. Here we report selectable markers that are not only useful but necessary for the selection of drug-resistant transformants in the setting of drug-resistant backgrounds. Use of these selectable markers can be applied to a variety of genetic and molecular techniques such as mutagenesis and transformation. These selectable markers will help promote genetic and molecular biology studies of otherwise onerous drug-resistant strains, while avoiding the generation of pathogenic organisms that are resistant to clinically relevant antibiotics.
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