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Petraitis V, Petraitiene R, Kavaliauskas P, Naing E, Garcia A, Zigmantaite V, Grigaleviciute R, Kucinskas A, Pockevicius A, Stakauskas R, Walsh TJ. Development of rabbit models of ventilator-associated bacterial pneumonia produced by carbapenem-resistant Pseudomonas aeruginosa. Antimicrob Agents Chemother 2024:e0020524. [PMID: 38687014 DOI: 10.1128/aac.00205-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 04/03/2024] [Indexed: 05/02/2024] Open
Abstract
Ventilator-associated bacterial pneumonia (VABP) is among the most intractable of carbapenem-resistant Gram-negative bacterial infections. New antimicrobial agents are critically needed for the treatment of VABP. However, current conventionally used animal model systems are inadequate to meet this challenge. We, therefore, developed rabbit models of VABP caused by carbapenem-resistant Pseudomonas aeruginosa. Persistently neutropenic New Zealand White rabbits were used throughout the study. The early-phase intubated model (0-24 h) received mechanical ventilation, while the late-phase intubated model (72-96 h) was ambulatory. The following outcome parameters were studied: survival, residual tissue bacterial burden (CFU/g), residual BAL bacterial burden (CFU/mL), lung weights, pulmonary lesion score, histology, O2 saturation, radiographic imaging, and histology. Each anesthetized rabbit received a predetermined endotracheal bacterial inoculum, and ventilators were set to FiO2 = 40% and PEEP = 8 mmHg. Within the first 12 h post-inoculation, mean bacterial burdens in lung tissue and BAL fluid, respectively, were established at approximately 107 CFU/g and 106 CFU/mL, persisted through 24 h in the early-phase model and increased in the late-phase model to approximately 108 CFU/g and 107 CFU/mL. Mean max SpO2 was ≥98 mmHg, and mean nadir SpO2 was ≥68 mmHg. Serial thoracic radiographs demonstrated progressive multilobar pneumonic infiltrates. Lung histology revealed progressive focal bronchopneumonia, coagulative necrosis, intra-alveolar hemorrhage, alveolar epithelial cell necrosis, and bacterial microcolonies. The new rabbit model of VABP produced by carbapenem-resistant Pseudomonas aeruginosa recapitulates the pathophysiological, microbiological, diagnostic imaging, and histological patterns of human disease by which to assess critically needed new antimicrobial agents against this lethal infection.
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Affiliation(s)
- Vidmantas Petraitis
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ruta Petraitiene
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
| | - Povilas Kavaliauskas
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ethan Naing
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
| | - Andrew Garcia
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
| | - Vilma Zigmantaite
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ramune Grigaleviciute
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Audrius Kucinskas
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Alius Pockevicius
- Department of Veterinary Pathobiology, Veterinary Academy, Pathology Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rimantas Stakauskas
- The Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Thomas J Walsh
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine of Cornell University, New York, New York, USA
- Center for Innovative Therapeutics and Diagnostics, Richmond, Virginia, USA
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Assoni L, Couto AJM, Vieira B, Milani B, Lima AS, Converso TR, Darrieux M. Animal models of Klebsiella pneumoniae mucosal infections. Front Microbiol 2024; 15:1367422. [PMID: 38559342 PMCID: PMC10978692 DOI: 10.3389/fmicb.2024.1367422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Klebsiella pneumoniae is among the most relevant pathogens worldwide, causing high morbidity and mortality, which is worsened by the increasing rates of antibiotic resistance. It is a constituent of the host microbiota of different mucosa, that can invade and cause infections in many different sites. The development of new treatments and prophylaxis against this pathogen rely on animal models to identify potential targets and evaluate the efficacy and possible side effects of therapeutic agents or vaccines. However, the validity of data generated is highly dependable on choosing models that can adequately reproduce the hallmarks of human diseases. The present review summarizes the current knowledge on animal models used to investigate K. pneumoniae infections, with a focus on mucosal sites. The advantages and limitations of each model are discussed and compared; the applications, extrapolations to human subjects and future modifications that can improve the current techniques are also presented. While mice are the most widely used species in K. pneumoniae animal studies, they present limitations such as the natural resistance to the pathogen and difficulties in reproducing the main steps of human mucosal infections. Other models, such as Drosophila melanogaster (fruit fly), Caenorhabditis elegans, Galleria mellonella and Danio rerio (zebrafish), contribute to understanding specific aspects of the infection process, such as bacterial lethality and colonization and innate immune system response, however, they but do not present the immunological complexity of mammals. In conclusion, the choice of the animal model of K. pneumoniae infection will depend mainly on the questions being addressed by the study, while a better understanding of the interplay between bacterial virulence factors and animal host responses will provide a deeper comprehension of the disease process and aid in the development of effective preventive/therapeutic strategies.
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Affiliation(s)
| | | | | | | | | | | | - Michelle Darrieux
- Laboratório de Microbiologia Molecular e Clínica, Universidade São Francisco, Bragança Paulista, Brazil
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Gras E, Vu TTT, Nguyen NTQ, Tran VG, Mao Y, Tran ND, Mai NH, Dong OX, Jung DH, Iorio NLPP, Povoa HCC, Pinheiro MG, Aguiar-Alves F, Weiss WJ, Zheng B, Cheng LI, Stover CK, Sellman BR, DiGiandomenico A, Gibault L, Valour F, Diep BA. Development and validation of a rabbit model of Pseudomonas aeruginosa non-ventilated pneumonia for preclinical drug development. Front Cell Infect Microbiol 2023; 13:1297281. [PMID: 38149013 PMCID: PMC10750358 DOI: 10.3389/fcimb.2023.1297281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/22/2023] [Indexed: 12/28/2023] Open
Abstract
Background New drugs targeting antimicrobial resistant pathogens, including Pseudomonas aeruginosa, have been challenging to evaluate in clinical trials, particularly for the non-ventilated hospital-acquired pneumonia and ventilator-associated pneumonia indications. Development of new antibacterial drugs is facilitated by preclinical animal models that could predict clinical efficacy in patients with these infections. Methods We report here an FDA-funded study to develop a rabbit model of non-ventilated pneumonia with Pseudomonas aeruginosa by determining the extent to which the natural history of animal disease reproduced human pathophysiology and conducting validation studies to evaluate whether humanized dosing regimens of two antibiotics, meropenem and tobramycin, can halt or reverse disease progression. Results In a rabbit model of non-ventilated pneumonia, endobronchial challenge with live P. aeruginosa strain 6206, but not with UV-killed Pa6206, caused acute respiratory distress syndrome, as evidenced by acute lung inflammation, pulmonary edema, hemorrhage, severe hypoxemia, hyperlactatemia, neutropenia, thrombocytopenia, and hypoglycemia, which preceded respiratory failure and death. Pa6206 increased >100-fold in the lungs and then disseminated from there to infect distal organs, including spleen and kidneys. At 5 h post-infection, 67% of Pa6206-challenged rabbits had PaO2 <60 mmHg, corresponding to a clinical cut-off when oxygen therapy would be required. When administered at 5 h post-infection, humanized dosing regimens of tobramycin and meropenem reduced mortality to 17-33%, compared to 100% for saline-treated rabbits (P<0.001 by log-rank tests). For meropenem which exhibits time-dependent bactericidal activity, rabbits treated with a humanized meropenem dosing regimen of 80 mg/kg q2h for 24 h achieved 100% T>MIC, resulting in 75% microbiological clearance rate of Pa6206 from the lungs. For tobramycin which exhibits concentration-dependent killing, rabbits treated with a humanized tobramycin dosing regimen of 8 mg/kg q8h for 24 h achieved Cmax/MIC of 9.8 ± 1.4 at 60 min post-dose, resulting in 50% lung microbiological clearance rate. In contrast, rabbits treated with a single tobramycin dose of 2.5 mg/kg had Cmax/MIC of 7.8 ± 0.8 and 8% (1/12) microbiological clearance rate, indicating that this rabbit model can detect dose-response effects. Conclusion The rabbit model may be used to help predict clinical efficacy of new antibacterial drugs for the treatment of non-ventilated P. aeruginosa pneumonia.
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Affiliation(s)
- Emmanuelle Gras
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Université François Rabelais, Tours, France
| | - Trang T. T. Vu
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Nhu T. Q. Nguyen
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Vuvi G. Tran
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Yanjie Mao
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Nguyen D. Tran
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | - Nam H. Mai
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Oliver X. Dong
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - David H. Jung
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Natalia L. P. P. Iorio
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Department of Basic Science, Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil
| | - Helvecio C. C. Povoa
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Department of Basic Science, Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil
| | - Marcos Gabriel Pinheiro
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Fabio Aguiar-Alves
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Pathology Program, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
| | - William J. Weiss
- Pre-Clinical Services at UNT Health Science Center, Fort Worth, TX, United States
| | - Bo Zheng
- Clinical Pharmacology & DMPK, AstraZeneca, Gaithersburg, MD, United States
| | - Lily I. Cheng
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | - Charles K. Stover
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | - Bret R. Sellman
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | | | - Laure Gibault
- Pathology Department, George Pompidou European Hospital, Paris, France
| | - Florent Valour
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
- Department of Infectious Diseases, Hospices Civils de Lyon, Lyon, France
- CIRI – Centre International de Recherche en Infectiologie, Inserm, U1111, University of Lyon, Lyon, France
- Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, University of Lyon, Lyon, France
| | - Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, United States
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Nguyen NTQ, Doan TNM, Sato K, Tkaczyk C, Sellman BR, Diep BA. Monoclonal antibodies neutralizing alpha-hemolysin, bicomponent leukocidins, and clumping factor A protected against Staphylococcus aureus-induced acute circulatory failure in a mechanically ventilated rabbit model of hyperdynamic septic shock. Front Immunol 2023; 14:1260627. [PMID: 37781371 PMCID: PMC10541218 DOI: 10.3389/fimmu.2023.1260627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/22/2023] [Indexed: 10/03/2023] Open
Abstract
Background Patients with septic shock caused by Staphylococcus aureus have mortality rates exceeding 50%, despite appropriate antibiotic therapy. Our objectives were to establish a rabbit model of S. aureus septic shock and to determine whether a novel immunotherapy can prevent or halt its natural disease progression. Methods Anesthetized rabbits were ventilated with lung-protective low-tidal volume, instrumented for advanced hemodynamic monitoring, and characterized for longitudinal changes in acute myocardial dysfunction by echocardiography and sepsis-associated biomarkers after S. aureus intravenous challenge. To demonstrate the potential utility of this hyperdynamic septic shock model for preclinical drug development, rabbits were randomized for prophylaxis with anti-Hla/Luk/ClfA monoclonal antibody combination that neutralizes alpha-hemolysin (Hla), the bicomponent pore-forming leukocidins (Luk) including Panton-Valentine leukocidin, leukocidin ED, and gamma-hemolysin, and clumping factor A (ClfA), or an irrelevant isotype-matched control IgG (c-IgG), and then challenged with S. aureus. Results Rabbits challenged with S. aureus, but not those with saline, developed a hyperdynamic state of septic shock characterized by elevated cardiac output (CO), increased stroke volume (SV) and reduced systemic vascular resistance (SVR), which was followed by a lethal hypodynamic state characterized by rapid decline in mean arterial pressure (MAP), increased central venous pressure, reduced CO, reduced SV, elevated SVR, and reduced left-ventricular ejection fraction, thereby reproducing the hallmark clinical features of human staphylococcal septic shock. In this model, rabbits pretreated with anti-Hla/Luk/ClfA mAb combination had 69% reduction in mortality when compared to those pretreated with c-IgG (P<0.001). USA300-induced acute circulatory failure-defined as >70% decreased in MAP from pre-infection baseline-occurred in only 20% (2/10) of rabbits pretreated with anti-Hla/Luk/ClfA mAb combination compared to 100% (9/9) of those pretreated with c-IgG. Prophylaxis with anti-Hla/Luk/ClfA mAb combination halted progression to lethal hypodynamic shock, as evidenced by significant protection against the development of hyperlactatemia, hypocapnia, hyperkalemia, leukopenia, neutropenia, monocytopenia, lymphopenia, as well as biomarkers associated with acute myocardial injury. Conclusion These results demonstrate the potential utility of a mechanically ventilated rabbit model that reproduced hallmark clinical features of hyperdynamic septic shock and the translational potential of immunotherapy targeting S. aureus virulence factors for the prevention of staphylococcal septic shock.
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Affiliation(s)
- Nhu T. Q. Nguyen
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Thien N. M. Doan
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Kei Sato
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Christine Tkaczyk
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | - Bret R. Sellman
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | - Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
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Pseudomonas aeruginosa: Infections, Animal Modeling, and Therapeutics. Cells 2023; 12:cells12010199. [PMID: 36611992 PMCID: PMC9818774 DOI: 10.3390/cells12010199] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 01/05/2023] Open
Abstract
Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen which causes many severe acute and chronic infections with high morbidity, and mortality rates as high as 40%. What makes P. aeruginosa a particularly challenging pathogen is its high intrinsic and acquired resistance to many of the available antibiotics. In this review, we review the important acute and chronic infections caused by this pathogen. We next discuss various animal models which have been developed to evaluate P. aeruginosa pathogenesis and assess therapeutics against this pathogen. Next, we review current treatments (antibiotics and vaccines) and provide an overview of their efficacies and their limitations. Finally, we highlight exciting literature on novel antibiotic-free strategies to control P. aeruginosa infections.
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Arrazuria R, Kerscher B, Huber KE, Hoover JL, Lundberg CV, Hansen JU, Sordello S, Renard S, Aranzana-Climent V, Hughes D, Gribbon P, Friberg LE, Bekeredjian-Ding I. Variability of murine bacterial pneumonia models used to evaluate antimicrobial agents. Front Microbiol 2022; 13:988728. [PMID: 36160241 PMCID: PMC9493352 DOI: 10.3389/fmicb.2022.988728] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/15/2022] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance has become one of the greatest threats to human health, and new antibacterial treatments are urgently needed. As a tool to develop novel therapies, animal models are essential to bridge the gap between preclinical and clinical research. However, despite common usage of in vivo models that mimic clinical infection, translational challenges remain high. Standardization of in vivo models is deemed necessary to improve the robustness and reproducibility of preclinical studies and thus translational research. The European Innovative Medicines Initiative (IMI)-funded “Collaboration for prevention and treatment of MDR bacterial infections” (COMBINE) consortium, aims to develop a standardized, quality-controlled murine pneumonia model for preclinical efficacy testing of novel anti-infective candidates and to improve tools for the translation of preclinical data to the clinic. In this review of murine pneumonia model data published in the last 10 years, we present our findings of considerable variability in the protocols employed for testing the efficacy of antimicrobial compounds using this in vivo model. Based on specific inclusion criteria, fifty-three studies focusing on antimicrobial assessment against Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii were reviewed in detail. The data revealed marked differences in the experimental design of the murine pneumonia models employed in the literature. Notably, several differences were observed in variables that are expected to impact the obtained results, such as the immune status of the animals, the age, infection route and sample processing, highlighting the necessity of a standardized model.
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Affiliation(s)
- Rakel Arrazuria
- Division of Microbiology, Paul-Ehrlich-Institut, Langen, Germany
| | | | - Karen E. Huber
- Division of Microbiology, Paul-Ehrlich-Institut, Langen, Germany
| | - Jennifer L. Hoover
- Infectious Diseases Research Unit, GlaxoSmithKline Pharmaceuticals, Collegeville, PA, United States
| | | | - Jon Ulf Hansen
- Department of Bacteria, Parasites & Fungi, Statens Serum Institut, Copenhagen, Denmark
| | | | | | | | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Discovery Research ScreeningPort, Hamburg, Germany
| | | | - Isabelle Bekeredjian-Ding
- Division of Microbiology, Paul-Ehrlich-Institut, Langen, Germany
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- *Correspondence: Isabelle Bekeredjian-Ding,
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Anti-virulence Bispecific Monoclonal Antibody Mediated Protection Against Pseudomonas aeruginosa Ventilator-Associated Pneumonia in a Rabbit Model. Antimicrob Agents Chemother 2021; 66:e0202221. [PMID: 34902264 PMCID: PMC8846318 DOI: 10.1128/aac.02022-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Ventilator-associated pneumonia is an important clinical manifestation of the nosocomial pathogen Pseudomonas aeruginosa. We characterized the correlates of protection of MEDI3902, a bispecific human IgG1 mAb that targets the P. aeruginosa type-3-secretion PcrV protein and the Psl exopolysaccharide, in a rabbit model of ventilator-associated pneumonia using lung-protective, low-tidal volume mechanical ventilation. Rabbits infused with MEDI3902 prophylactically were protected, whereas those pretreated with irrelevant isotype-control IgG (c-IgG) succumbed between 12 and 44 hours post infection [100% (8/8) vs. 0% (8/8) survival, P<0.01 by log-rank test]. Lungs from rabbits pretreated with c-IgG, but not those with MEDI3902, had bilateral, multifocal areas of marked necrosis, hemorrhage, neutrophilic inflammatory infiltrate, diffuse fibrinous edema in alveolar spaces. All rabbits pretreated with c-IgG developed worsening bacteremia that peaked at the time of death, whereas only 38% (3/8) rabbits pretreated with MEDI3902 developed such high-grade bacteremia (two-sided Fisher's exact test, P=0.026). Biomarkers associated with acute respiratory distress syndrome were evaluated longitudinally in blood samples collected every 2-4 hours to assess systemic pathophysiological changes in rabbits pretreated with MEDI3902 or c-IgG. Biomarkers were sharply increased or decreased in rabbits pretreated with c-IgG, but not those pretreated with MEDI3902, including ratio of arterial oxygen partial pressure to fractional inspired oxygen PaO2/FiO2 <300, hypercapnia or hypocapnia, severe lactic acidosis, leukopenia and neutropenia. Cytokines and chemokines associated with ARDS were significantly downregulated in lungs from rabbits pretreated with MEDI3902 compared with c-IgG. These results suggest that MEDI3902 prophylaxis could have potential clinical utility for decreasing severity of P. aeruginosa ventilator-associated pneumonia.
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