The Lysis of Pathogenic Escherichia coli by Bacteriophages Releases Less Endotoxin Than by β-Lactams.
Other than numerous experimental data assessing phage therapy efficacy, questions regarding safety of this approach are not sufficiently addressed. In particular, as phages can kill bacterial cells within <10 minutes, the associated endotoxin release (ER) in severe infections caused by gram-negative bacteria could be a matter of concern.
Two therapeutic virulent phages and 4 reference antibiotics were studied in vitro for their ability to kill 2 pathogenic strains of Escherichia coli and generate an ER. The early interaction (first 3 hours) between these actors was assessed over time by studying the instantaneous cell viability, the colony-forming unit count, the concentration of free endotoxin released, and the cell morphology under light microscope.
While β-lactams have a relatively slow effect, both tested phages, as well as amikacin, were able to rapidly abolish the bacterial growth. Even when considering the fastest phage (cell lysis in 9 minutes), the concentrations of phage-induced ER never reached the highest values, which were recorded with antibiotic treatments. Cumulative concentrations of endotoxin over time in phage-treated conditions were lower than those observed with β-lactams and close to those observed with amikacin. Whereas β-lactams were responsible for strong cell morphology changes (spheroplast with imipenem, filamentous cells with cefoxitin and ceftriaxone), amikacin and phages did not modify cell shape but produced intracellular inclusion bodies.
This work provides important and comforting data regarding the safety of phage therapy. Therapeutically relevant phages, with their low endotoxin release profile and fast bactericidal effect, are not inferior to β-lactams.
Institut Pasteur, Department of Microbiology, Molecular Biology of Gene in Extremophiles, Paris.|Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Louis Mourier, Service de Réanimation Médico-Chirurgicale, Colombes.|INSERM, IAME, UMR 1137, Paris.
Nicolas
N
Dufour
Institut Pasteur, Department of Microbiology, Molecular Biology of Gene in Extremophiles, Paris.|INSERM, IAME, UMR 1137, Paris.|AP-HP, Hôpital Beaujon, Service d'Anesthésie-Réanimation, Clichy ; and.
Raphaëlle
R
Delattre
Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Louis Mourier, Service de Réanimation Médico-Chirurgicale, Colombes.|INSERM, IAME, UMR 1137, Paris.|Université Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, Paris, France.
Jean-Damien
JD
Ricard
Institut Pasteur, Department of Microbiology, Molecular Biology of Gene in Extremophiles, Paris.
Laurent
L
Debarbieux
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D003090:Coliphages / Q000502:physiology*; D004731:Endotoxins / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity / Q000821:virology*; D004927:Escherichia coli Infections / Q000628:therapy; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D000071059:Phage Therapy / Q000009:adverse effects; D013104:Spheroplasts / Q000187:drug effects / Q000648:ultrastructure; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004731:Endotoxins; D047090:beta-Lactams; C044101:endotoxin, Escherichia coli; D015378:Imipenem
cell lysis; endotoxin; phage therapy; safety; β-lactams.