Synergistic effect of Coriandrum sativum L. extracts with cefoxitin against methicillin resistant Staphylococcus aureus, extended-spectrum beta-lactamase producing Escherichia coli and Klebsiella pneumoniae

Abstract

Antibiotic resistance has become a general health problem that makes the treatment decisions of clinicians more difficult. Recently, plants and their compounds have been suggested as a potential alternative to antimicrobials.The present study was carried out to evaluate for the first time, possible synergistic interactions on the antibacterial efficacy of Coriandrum sativum L. seed extracts and cefoxitin in combination against three important nosocomial pathogens (methicillin resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae). The antibacterial effect studied using the disc diffusion and synergism was showed by checkerboard methods. In the disc diffusion method, combinations of both methanol (ME, 1250 µg/mL) and petroleum ether extracts (PE, 1250 µg/mL) with cefoxitin (30 µg/mL) showed an increase in antibacterial activity against all tested microorganisms. It was found that, combinations of Coriander seed ME and PE extracts with cefoxitin have synergistic interactions against ESBL positive K. pneumoniae at 0.03516 and 0.03125 Fractional inhibitory concentration (FIC) index (FICI), respectively. The FICI of combinations against MRSA and E.coli were found to be indifferent by the checkerboard method. An antagonistic effect was not found in these combinations. The current study clearly suggests the potential usage of Coriander seed extracts alone and in combination with cefoxitin for combating infections by ESBL positive K. pneumoniae strains