Faced with multi-resistant infections, the return of phages, these bacteria-killing viruses

In the Cellular and Molecular Technology Laboratory (LabMCT) of the Reine-Astrid military hospital in Brussels, associate Maia Merabishvili presents a series of test tubes containing a yellowish liquid solution to one of Europe’s largest burn services. “Here, the bacterium was placed in the presence of the undiluted phage preparation”describes the Georgian biologist trained at the George Eliava Institute in Tbilisi, pointing to the first tube, the contents of which are translucent.

“In the next tube, this preparation was diluted ten times, and so on from tube to tube. We evaluate at what dilution the phage loses its power to destroy bacteria.she explains, extracting one of the tubes whose contents have become opacified due to bacterial growth.

The phages? These viruses, which infect bacteria, and not human cells, were used therapeutically (phage therapy) in Western countries, first against dysentery and then against certain infections until the 1940s, before being abandoned in favor of antibiotics. . The use of phage therapy has however been retained in the countries of the former Soviet bloc, notably in Georgia and Poland, which have become references for the characterization of phages.

Therapeutic potential

“The technique used by Maia Merabishvili is inherited from the time of Félix d’Hérelle [microbiologiste français, 1873-1949], considered the inventor of phage therapy. It is important to integrate it into the know-how we are developing”adds biologist Jean-Paul Pirnay, who directs the LabMCT. “But we also need modern sequencing and automation techniques to characterize the molecular mechanisms by which phages and bacteria co-evolve and to tune their interactions to make the most of their therapeutic potential, including their synergies with antibiotics “he argues.

In the adjoining room, in the automated incubator which the laboratory has just equipped itself with, different combinations of bacteria, bacteriophages and antibiotics are tested for each case of multi-resistant infection affecting a patient in the burns department in Brussels or a another hospital faced with the same therapeutic impasse. A camera produces an image of the culture every quarter of an hour, from which data on the level of bacterial growth inhibition is deduced. Enough to generate a curve for each combination. “From these curves, we deduce in particular the growth rate of the bacterium, the latency time indicating the duration during which this growth is inhibited and the moment at which a resistant strain emerges”explains Maia Merabishvili with conviction, pointing to the curves on a computer screen.

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