title: Structural and Enzymatic Characterization of ABgp46, a Novel Phage Endolysin with Broad Anti-Gram-Negative Bacterial Activity.
abstract: The present study demonstrates the antibacterial potential of a phage endolysin against Gram-negative pathogens, particularly against multidrug resistant strains of Acinetobacter baumannii. We have cloned, heterologously expressed and characterized a novel endolysin (ABgp46) from Acinetobacter phage vb_AbaP_CEB1 and tested its antibacterial activity against several multidrug-resistant A. baumannii strains. LC-MS revealed that ABgp46 is an N-acetylmuramidase, that is also active over a broad pH range (4.0-10.0) and temperatures up to 50°C. Interestingly, ABgp46 has intrinsic and specific anti-A. baumannii activity, reducing multidrug resistant strains by up to 2 logs within 2 h. By combining ABgp46 with several organic acids that act as outer membrane permeabilizing agents, it is possible to increase and broaden antibacterial activity to include other Gram-negative bacterial pathogens. In the presence of citric and malic acid, ABgp46 reduces A. baumannii below the detection limit (>5 log) and more than 4 logs Pseudomonas aeruginosa and Salmonella typhimurium strains. Overall, this globular endolysin exhibits a broad and high activity against Gram-negative pathogens, that can be enhanced in presence of citric and malic acid, and be used in human and veterinary medicine.
authors.affiliation: Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Oliveira
authors.affiliation: Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Vilas Boas
authors.affiliation: Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield Sheffield, UK.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Mesnage
authors.affiliation: Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal.
authors.forename: Leon D
authors.initials: LD
authors.lastname: Kluskens
authors.affiliation: Laboratory of Gene Technology, KU Leuven Leuven, Belgium.
authors.forename: Rob
authors.initials: R
authors.lastname: Lavigne
authors.affiliation: Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal.
authors.forename: Sanna
authors.initials: S
authors.lastname: Sillankorva
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare - Consiglio Nazionale delle Ricerche Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Secundo
authors.affiliation: Centre of Biological Engineering, Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho Braga, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Azeredo
keywords: Acinetobacter baumannii; antibacterial activity; circular dichroism; mass spectrometry; phage endolysins