Objective :
In cystic fibrosis patients, broncho-pulmonary infection by different pathogenic bacteria, and in particular by P. aeruginosa and S. aureus, is responsible for worsening of the disease. There are more and more strains that are resistant to several antibiotics. Another way to fight these infections might be the use of viruses or bacteriophages, capable to attack and destroy specifically pathogenic bacteria. In order to evaluate the interest of this therapeutic approach named phage therapy, to treat cystic fibrosis patients, a better knowledge of the principal pathogenic bacteria and of their bacteriophages is necessary. Our objective is to study the infection spectrum of a large bacteriophage collection toward P. aeruginosa and S. aureus strains isolated from cystic fibrosis patients, in order to characterise the basis for host specificity as well as the mechanisms of resistance. Thanks to a collaboration with a Georgian Institute specialised in phage therapy, we have access to bacteriophages selected for their virulence toward many strains. A close collaboration with the CRCM of Hôpital Trousseau will allow to study the effect of bacteriophages, almost in ex vivo conditions, against the clinical strains directly isolated from patients sputum, especially those showing a mucoïd phenotype in the case of P. aeruginosa. Indeed it is well known that this characteristic is generally lost in subculture of frozen stored strains.
The study of alternative solutions to antibiotics to fight bacterial infections, such as phage therapy, is necessary. It is now primordial to study the bacteriophages active against P. aeruginosa and S. aureus, the two major pathogens for children suffering from cystic fibrosis. It might be someday possible to use a cocktail of bacteriophages, active against different bacteria species, by aerosol administration, as this was done in several clinical assays in Georgia and many other countries.
