Use of bacteriophage endolysin EL188 and outer membrane permeabilizers against Pseudomonas aeruginosa.
OBJECTIVE
To select and evaluate an appropriate outer membrane (OM) permeabilizer to use in combination with the highly muralytic bacteriophage endolysin EL188 to inactivate (multi-resistant) Pseudomonas aeruginosa.


RESULTS
We tested the combination of endolysin EL188 and several OM permeabilizing compounds on three selected Ps. aeruginosa strains with varying antibiotic resistance. We analysed OM permeabilization using the hydrophobic probe N-phenylnaphtylamine and a recombinant fusion protein of a peptidoglycan binding domain and green fluorescent protein on the one hand and cell lysis assays on the other hand. Antibacterial assays showed that incubation of 10(6) Ps. aeruginosa cells ml(-1) in presence of 10 mmol l(-1) ethylene diamine tetraacetic acid disodium salt dihydrate (EDTA) and 50 μg ml(-1) endolysin EL188 led to a strain-dependent inactivation between 3·01 ± 0·17 and 4·27 ± 0·11 log units in 30 min. Increasing the EL188 concentration to 250 μg ml(-1) further increased the inactivation of the most antibiotic resistant strain Br667 (4·07 ± 0·09 log units).


CONCLUSIONS
Ethylene diamine tetraacetic acid disodium salt dihydrate was selected as the most suitable component to combine with EL188 in order to reduce Ps. aeruginosa with up to 4 log units in a time interval of 30 min.


CONCLUSIONS
This in vitro study demonstrates that the application range of bacteriophage encoded endolysins as 'enzybiotics' must not be limited to gram-positive pathogens.
Division of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, Leuven, Belgium.
Y
Y
Briers
M
M
Walmagh
R
R
Lavigne
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004352:Drug Resistance, Microbial / Q000187:drug effects; D004492:Edetic Acid / Q000494:pharmacology*; D010450:Endopeptidases / Q000494:pharmacology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D050296:Microbial Viability / Q000187:drug effects*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D049452:Green Fluorescent Proteins; D004492:Edetic Acid; D010450:Endopeptidases; C001143:endolysin