Caractérisation des souches de Staphylococcus aureus résistantes à la méticilline (SARM) et évaluation de leur sensibilité à la propolis.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has come to be one of the primary causes of nosocomial and community infections worldwide. The main objective of this thesis was to evaluate the antibacterial activity of propolis ethanol extract EEP with respect to multidrug-resistant bacteria (MRSA). In order to achieve so, clinically isolated MRSA strains had been selected and then studied their resistance profile to different antibiotics families. Methicillin resistance detection has been completed by looking for mecA gene via PCR. The synergy among EEP and 12 anti-staphylococcal antibiotics has also been studied. Antibiotic sensibility study allowed us to detect 34 strains of S. aureus resistant to methicillin MRSA (21.11%) from diverse samples: pus, blood cultures, urine, vaginal samples and equipment (catheters). The resistance profile analysis of antibiotic MRSA approved the multi-resistant nature of these bacteria to different antibiotics families: aminoglycosides, macrolides and fluoroquinolones. DNA extracts Analysis of 24 MRSA strains by amplification indicated the presence of the mecA gene in 21 strains, showing that this gene was responsible for methicillin resistance in these strains. Antibacterial activity assessment of propolis revealed that EEP exhibited worthy antibacterial activity with respect to all MSSA and MRSA strains. The average MIC and CMB values against the MSSA strains were respectively 0.55 ± 0.45 mg/ml and 5.5 ± 4.5 mg/ml. In the case of MRSA strains, the MIC and CMB were correspondingly: 0.67 ± 0.41 mg/ ml and 6.72 ± 4.16 mg/ml. The addition of EEP at a concentration of 0.25 mg/ml in the medium improved the MRSA strains sensibility to all antibiotics. This analysis showed a synergy between EPP and all tested antibiotics. On the other hand, no case of antagonism between PEF and tested antibiotics was recorded. This reported synergy was relevant, and propolis can be an alternative for these pathogens treatment.