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A7571 - Intratracheal Phage Therapy Against Acinetobacter Baumannii Lung Infection in Mice
Author Block: S. Wienhold1, M. C. Brack1, G. Nouailles1, N. W. Suttorp1, C. Seitz2, A. Ross2, H. Ziehr2, C. Gurtner3, O. Kershaw3, K. Dietert3, A. D. Gruber3, M. Rohde4, C. Rohde5, M. Witzenrath1; 1Department of Infectious Diseases and Pulmonary Medicine, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany, 2Department of Pharmaceutical Biotechnology, Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Braunschweig, Germany, 3Department of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany, 4Helmholtz Centre for Infection Research, Braunschweig, Germany, 5Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.
RATIONALE Lung infections caused by multidrug resistant bacteria (MDR) are an increasing problem in modern medicine. Acinetobacter baumannii, the pathogen with the highest critical priority according to the WHO (Sept. 2017), is frequently almost untreatable even with modern broad-spectrum antibiotics. Phage therapy regained its popularity in treatment of bacterial infections due to their high specificity and effectivity in bacterial lysis. Nonetheless, phages need to be properly characterized and possible adverse effects should be identified. In anticipation of a future clinical trial applying aerosolized lytic phages against Acinetobacter baumannii, this preclinical study determined the efficacy, safety and tolerability of a novel phage preparation in mice.
METHODS Mice were transnasally infected with a MDR A. baumannii strain [1] and 12h later treated with a specific phage preparation or solvent intratracheally. Therefore, phage Acibel004 [2] was produced as high-titer suspension subjected to final processing including highly efficient depletion of endotoxins by chromatography. At defined timepoints clinical parameters were measured, bacterial burden was determined and cell-influx was analyzed. Lung-permeability and cytokine-release were quantified and histopathological examination was performed. Furthermore, presence of vital phages was determined.
RESULTS Clinical outcome of phage treated mice was improved. Mice recovered faster from infection-associated hypothermia. Bacterial loads in lungs and BALF of the phage-treated group were significantly reduced by 48 h after infection. Also, lung permeability and the production of cytokines were significantly reduced. Hematoxylin and eosin stained lung slides of phage treated mice showed less spreading of bacteria to periphery, whereas cellular recruitment into the lung was unaffected by phage treatment. Phages were detected in BALF, lungs and plasma of treated mice. No adverse effects were observed.
CONCLUSION For the first time a highly purified phage preparation against A. baumannii was used successfully. The current preclinical data further support the concept of developing a phage-based therapy against pulmonary A. baumannii infections.
ACKNOWLEDGEMENTS This study was funded by SFB-TR84 and by the Manchot Stiftung (stipend for M. Brack). Phage vB_AbaM_Acibel004 was kindly provided by M. Merabishvili PhD. Acinetobacter baumannii RUH2037 was kindly provided by Dr. A. F. de Vos PhD and Prof. Dr. T. van der Poll.
[1] Knapp S, et al. Differential roles of CD14 and toll-like receptors 4 and 2 in murine Acinetobacter pneumonia. Am J Respir Crit Care Med. 2006 Jan 1;173(1):122-9.
[2] Merabishvili M, et al. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii. PLoS One. 2014 Aug 11;9(8):e104853.