Abstract
Urinary Tract Infection (UTI) is a major problem of public health. Acute cystitis which touches mostly women is the most common form of UTI. The bacteria which is mostly isolated in an UTI is Escherichia coli. A particularity of cystitis is to come back. In this context news strategies have to be developed to prevent and cure recurrent UTI. One of these strategies is the utilization of natural products like the cranberry (Vaccinium macrocarpon) which is promising. Indeed, previous studies showed the negative impact of cranberry on the adhesion of bacteria on the superficial cells of bladder which help the elimination of bacteria by the urinary flux. This activity is carried by the type A proanthocyanidin (PAC-A). Moreover, a study lead by our team has demonstrated an improvement of the activity of cranberry on the adhesion and the virulence of uropathogenic E. coli (UPEC) by another natural product: the propolis. Since Antiquity its antibacterial activities have been recognize and more recent studies have demonstrated its impact of Gram positive bacteria and also on two Gram negative bacteria: E. coli and Pseudomonas aeruginosa. This thesis has allowed for: i) the description of the impact of cranberry, propolis and its association on the transcriptome of a clinical strain of UPEC (G50). This transcriptomic analyze have shown that the cranberry down regulated genes linked to the adhesion and also genes linked to the motility and biofilm formation. However the cranberry up regulated genes linked to the iron metabolism and the stress response. These effects are improve by the addition of propolis. Concurrently phenotypics tests have been conducted on a collection of UPEC on the motility and the biofilm formation and they confirmed the previous results; ii) the development of a test, based on our transcriptomic results, enable to performed a standardized evaluation of the impact of PAC-A on E. coli, independently of its concentration. Indeed, this molecule cannot be measure in a standard way. Four genes have been selected (tsr, ftnA, fecB, feoB), the monitoring of their expression allow us to measure the anti-bacterial efficiency of the cranberry; iii) the measurement of the potential effect of the propolis of the antibiotic’s activities used to treat UTIs. Thus it have been observed that the addition of propolis improve the bactericide activity of the antibiotics tested and reduces the minimal inhibitory concentration of these antibiotics.