Potentialisation de l’effet antimicrobien des antibiotiques par l’extrait méthanolique de Emilia coccinea (Asteraceae) vis-à-vis de quelques isolats cliniques de Helicobacter pylori à phénotype multi-drugs-résistants

Abstract

H. pylori is the only bacterial species recognized by the World Health Organization (WHO) as being carcinogenic for Man. Because of the defect of observance of the patient and mainly to resistance of antibiotics formerly effective against this bacterium, about half of the world population is infected by it, particularly in the developing countries. In parallel, many medicinal plants showed more than one once their properties antimicrobic; nearly 80% of the populations depend on traditional medicine for their care on primary health. Within the framework of the fight against the unceasingly increasing emergence of the resistance of the stocks of H. pylori, the principal objective of our work was to potentiate the antimicrobic effect of some usual antibiotics by the extracts of medicinal plants towards ten clinical isolates of H. pylori with phenotype multi-drugs-resistant. This by evaluating in vitro the anti-H pylori activity of 16 extracts of medicinal plants and 6 usual antibiotics by the method of microdilution in liquid medium initially; then by evaluating in vitro the anti-H pylori activity of associations of extracts of plant and antibiotics by the method of the chess-board. Only the methanolic extract of Emilia coccinea showed a notable anti-H. pylori activity with a value of CMI of 64 μg/ml towards 60% of the clinical isolates used.Contrary to clarithromycin, doxycyclin and ciprofloxacin which presented an anti-H.pylori activity very high towards all the clinical isolates (CMI = 0.125 μg/ml), amoxicillin, erythromycin and metronidazole did not present any antimicrobic activity (CMI very high ≥ 128 μg/ml). The methanolic extract of Emilia coccinea association with amoxicillin presented synergy effects (FIC < 0.0625 and FIC < 0.125), that with the erythromycin presented synergy (FIC = 0.0625) and addition (FIC = 1) effects and that with the metronidazole presented addition effects (FIC= 1). It thus comes out from this study that methanolic extract of Emilia coccinea (Asteraceae) would potentiate the antimicrobic effects of amoxicillin, of erythromycin and of metronidazole towards some clinical isolates of Helicobacter pylori with phenotype multi-drugs-resistant.