Etudes des activités anti-adhérentielles et anti-bactériennes de la canneberge (Vaccinium macrocarpon) et de la propolis

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.L’infection urinaire (IU) est un problème majeur de Santé publique. La cystite aiguë touchant principalement les femmes est la plus fréquente des IU. La bactérie la plus fréquemment isolée au cours de ces IU est Escherichia coli. Une des particularités de la cystite est sa propension à récidiver. Le traitement préconisé pour ces infections est la prise d’antibiotiques, qui peut être fréquente en cas de cystites récidivantes. C’est dans ce contexte que de nouvelles stratégies doivent être développées afin de prévenir et traiter les IU récidivantes. Parmi ces différentes stratégies, l’utilisation de produits naturels tels que la canneberge (Vaccinium macrocarpon) apparaît comme prometteuse. En effet, des études précédentes ont montré que la canneberge a un effet négatif sur l’adhésion des bactéries aux cellules superficielles de l’épithélium vésical facilitant l’élimination des bactéries par le flux urinaire. Cette activité est portée par la proanthocyanidine de type A (PAC-A). D’autre part, une étude menée par notre équipe a montré que l’effet de la canneberge sur l’adhésion et la virulence de souches d’E. coli uropathogènes pouvait être potentialisé par l’ajout d’un autre composé naturel : la propolis. Depuis l’Antiquité ses propriétés anti-bactériennes sont reconnues et des études plus récentes ont démontré son impact sur des bactéries à Gram positif mais également sur deux bactéries à Gram négatif : E. coli et Pseudomonas aeruginosa. Ce travail de thèse a permis : i) de décrire l’impact de la canneberge, de la propolis et de leur association sur le transcriptome d’une souche clinique d’E. coli uropathogène (G50). Cette analyse transcriptomique a montré que la canneberge entrainait une sous-expression de gènes liés à l’adhésion, mais également de gènes liés à la mobilité et à la formation de biofilm. En revanche, la canneberge augmentait l’expression des gènes liés au métabolisme du fer ainsi qu’à la réponse au stress. Ces effets étaient potentialisés par l’ajout de la propolis. En parallèle, des tests phénotypiques menés sur une collection de souches d’E. coli uropathogènes sur la mobilité et la formation de biofilm ont confirmé les résultats précédents ; ii) de développer un test, basé sur les précédents travaux de transcriptomique, permettant une évaluation standardisée de l’effet de la PAC-A sur E. coli, indépendamment de sa concentration car il n’existe pas de techniques standardisées pour doser cette molécule. C’est ainsi que 4 gènes (tsr, ftnA, fecB, feoB) ont été sélectionnés, le suivi de leur expression permettant une mesure de l’activité anti-bactérienne de la canneberge; iii) de mesurer l’effet potentialisateur de la propolis sur l’activité des antibiotiques utilisés dans le traitement des IU. C’est ainsi qu’il a été montré que l’ajout de la propolis permettait d’augmenter l’activité bactéricide des antibiotiques testés et de diminuer les concentrations minimales inhibitrices de ces antibiotiques

Study of the anti-adherential and anti-bacterial effect of cranberryand propolis

L’infection urinaire (IU) est un problème majeur de Santé publique. La cystite aiguë touchant principalement les femmes est la plus fréquente des IU. La bactérie la plus fréquemment isolée au cours de ces IU est Escherichia coli. Une des particularités de la cystite est sa propension à récidiver. Le traitement préconisé pour ces infections est la prise d’antibiotiques, qui peut être fréquente en cas de cystites récidivantes. C’est dans ce contexte que de nouvelles stratégies doivent être développées afin de prévenir et traiter les IU récidivantes. Parmi ces différentes stratégies, l’utilisation de produits naturels tels que la canneberge (Vaccinium macrocarpon) apparaît comme prometteuse. En effet, des études précédentes ont montré que la canneberge a un effet négatif sur l’adhésion des bactéries aux cellules superficielles de l’épithélium vésical facilitant l’élimination des bactéries par le flux urinaire. Cette activité est portée par la proanthocyanidine de type A (PAC-A). D’autre part, une étude menée par notre équipe a montré que l’effet de la canneberge sur l’adhésion et la virulence de souches d’E. coli uropathogènes pouvait être potentialisé par l’ajout d’un autre composé naturel : la propolis. Depuis l’Antiquité ses propriétés anti-bactériennes sont reconnues et des études plus récentes ont démontré son impact sur des bactéries à Gram positif mais également sur deux bactéries à Gram négatif : E. coli et Pseudomonas aeruginosa. Ce travail de thèse a permis : i) de décrire l’impact de la canneberge, de la propolis et de leur association sur le transcriptome d’une souche clinique d’E. coli uropathogène (G50). Cette analyse transcriptomique a montré que la canneberge entrainait une sous-expression de gènes liés à l’adhésion, mais également de gènes liés à la mobilité et à la formation de biofilm. En revanche, la canneberge augmentait l’expression des gènes liés au métabolisme du fer ainsi qu’à la réponse au stress. Ces effets étaient potentialisés par l’ajout de la propolis. En parallèle, des tests phénotypiques menés sur une collection de souches d’E. coli uropathogènes sur la mobilité et la formation de biofilm ont confirmé les résultats précédents ; ii) de développer un test, basé sur les précédents travaux de transcriptomique, permettant une évaluation standardisée de l’effet de la PAC-A sur E. coli, indépendamment de sa concentration car il n’existe pas de techniques standardisées pour doser cette molécule. C’est ainsi que 4 gènes (tsr, ftnA, fecB, feoB) ont été sélectionnés, le suivi de leur expression permettant une mesure de l’activité anti-bactérienne de la canneberge; iii) de mesurer l’effet potentialisateur de la propolis sur l’activité des antibiotiques utilisés dans le traitement des IU. C’est ainsi qu’il a été montré que l’ajout de la propolis permettait d’augmenter l’activité bactéricide des antibiotiques testés et de diminuer les concentrations minimales inhibitrices de ces antibiotiques.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

Propolis potentiates the effect of cranberry (Vaccinium macrocarpon) in reducing the motility and the biofilm formation of uropathogenic Escherichia coli.

One strategy to prevent urinary tract infections is the use of natural products such as cranberry (Vaccinium macrocarpon) and propolis. The objective of this study was to evaluate the impact of these products alone and combined on the motility and biofilm formation of a collection of representative uropathogenic Escherichia coli (UPEC). Motility was evaluated by the swarming and swimming capacity of the isolates in presence/absence of cranberry ± propolis. Early and late biofilm formation was observed with the Biofilm Ring test (BioFilm Control) and the crystal violet method. Cranberry alone was seen to have a variable effect on motility and biofilm formation unrelated to bacterial characteristics, but a reduced motility and biofilm formation was observed for all the isolates in the presence of cranberry + propolis. These results suggest that cranberry alone doesn't work on all the E. coli strains and propolis potentiates the effect of cranberry on UPEC, representing a new strategy to prevent recurrent urinary tract infections

Synergistic Effect of Propolis and Antibiotics on Uropathogenic Escherichia coli

International audienceUrinary tract infections (UTIs) are the most common bacterial infections around the world. Uropathogenic Escherichia coli (UPEC) is among the main pathogens isolated in UTIs. The rate of UPEC with high resistance towards antibiotics and multidrug-resistant bacteria have increased dramatically and conduct to the difficulty to treat UTIs. Due to the rarefaction of new antibiotics molecules, new alternative strategies must be evaluated. Since many years, propolis has demonstrated an interesting antibacterial activity against E. coli. Here, we evaluated its activity added to antibiotics on a panel of UPEC with different resistance mechanisms. Minimal inhibitory concentrations (MICs) and time–kill curves of fosfomycin, ceftriaxone, ertapenem and ofloxacin, with and without propolis, were determined. Significant diminution of the MICs was observed using ceftriaxone or ofloxacin + propolis. Propolis alone had a bacteriostatic activity with time-dependent effect against UPEC. The addition of this nutraceutical improved the effect of all the antibiotics evaluated (except fosfomycin) and showed a synergistic bactericidal effect (fractional inhibitory concentrations index ≤ 0.5 and a decrease ≥ 2 log CFU/mL for the combination of propolis plus antibiotics compared with the antibiotic alone). Propolis is able to restore in vitro antibiotic susceptibility when added to antibiotics against UPEC. This study showed that propolis could enhance the efficiency of antibiotics used in UTIs and could represent an alternative solution

Propolis potentiates the effect of cranberry (Vaccinium macrocarpon) against the virulence of uropathogenic Escherichia coli

International audienceUropathogenic Escherichia coli (UPEC), the most prevalent bacteria isolated in urinary tract infections (UTI), is now frequently resistant to antibiotics used to treat this pathology. The antibacterial properties of cranberry and propolis could reduce the frequency of UTIs and thus the use of antibiotics, helping in the fight against the emergence of antibiotic resistance. Transcriptomic profiles of a clinical UPEC strain exposed to cranberry proanthocyanidins alone (190 \textmug/mL), propolis alone (102.4 \textmug/mL) and a combination of both were determined. Cranberry alone, but more so cranberry + propolis combined, modified the expression of genes involved in different essential pathways: down-expression of genes involved in adhesion, motility, and biofilm formation, and up-regulation of genes involved in iron metabolism and stress response. Phenotypic assays confirmed the decrease of motility (swarming and swimming) and biofilm formation (early formation and formed biofilm). This study showed for the first time that propolis potentiated the effect of cranberry proanthocyanidins on adhesion, motility, biofilm formation, iron metabolism and stress response of UPEC. Cranberry + propolis treatment could represent an interesting new strategy to prevent recurrent UTI

Alternative Therapeutic Options to Antibiotics for the Treatment of Urinary Tract Infections

International audienceUrinary tract infections (UTIs) mainly caused by Uropathogenic Escherichia coli (UPEC), are common bacterial infections. Many individuals suffer from chronically recurring UTIs, sometimes requiring long-term prophylactic antibiotic regimens. The global emergence of multi-drug resistant uropathogens in the last decade underlines the need for alternative non-antibiotic therapeutic and preventative strategies against UTIs. The research on non-antibiotic therapeutic options in UTIs has focused on the following phases of the pathogenesis: colonization, adherence of pathogens to uroepithelial cell receptors and invasion. In this review, we discuss vaccines, small compounds, nutraceuticals, immunomodulating agents, probiotics and bacteriophages, highlighting the challenges each of these approaches face. Most of these treatments show interesting but only preliminary results. Lactobacillus-containing products and cranberry products in conjunction with propolis have shown the most robust results to date and appear to be the most promising new alternative to currently used antibiotics. Larger efficacy clinical trials as well as studies on the interplay between non-antibiotic therapies, uropathogens and the host immune system are warranted

PSMs of hypervirulent Staphylococcus aureus act as intracellular toxins that kill infected osteoblasts.

Epidemic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is associated with more severe and acute forms of osteomyelitis than healthcare-associated (HA-) MRSA. Although S. aureus is now recognized as a facultative intracellular pathogen, the contribution of osteoblast invasion by CA-MRSA to the pathogenesis of osteomyelitis is unknown. Using an ex vivo model of intracellular infection of human osteoblasts, we demonstrated that CA-MRSA strains of diverse lineages share an enhanced ability to kill infected osteoblasts compared to HA-MRSA. Cytotoxicity comparisons of CA-MRSA isogenic deletion mutants revealed that phenol-soluble modulins (PSMs), a class of membrane-damaging exoproteins that are expressed at higher levels in CA-MRSA than in HA-MRSA, are involved in this osteoblast killing, whereas other major CA-MRSA virulence determinants, the Panton-Valentine leukocidin and alpha-toxin, are not involved. Similarly, functional agr and sarA regulators, which control the expression of PSMs and alpha-toxin, were required for the expression of the intracellular cytotoxic phenotype by CA-MRSA, whereas the saeRS regulator, which controls the expression of alpha-toxin but not PSMs, had no impact on cytotoxicity. Finally, PSM transcript levels determined by quantitative reverse-transcriptase PCR were significantly higher in CA-MRSA than in HA-MRSA strains and associated with cell damage in MRSA-infected osteoblasts. These findings provide new insights into the pathogenesis of severe CA-MRSA osteomyelitis and unravel a novel virulence strategy of CA-MRSA, based on the invasion and subsequent killing of osteoblasts by PSMs acting as intracellular toxins