Antibiotic potentiating effect of Bergenia ciliata (Haw.) Sternb. against methicillin-resistant Staphylococcus aureus

Bergenia ciliata (Haw.) Sternb., belonging to the Family Saxifragaceae, is a perennial herb and is used in traditional medicine. The present study evaluated the antibacterial activity, synergistic activity, and antibiotic potentiating effect of the methanol extract of Bergenia ciliata (Haw.) Sternb. rhizome against methicillin-resistant Staphylococcus aureus (MRSA). Antibacterial screening results showed the average zone of inhibition of 20 ± 0 mm to 23 ± 0 mm against the tested isolates at the concentration of 500 mg/ml. The plant extract showed the minimum inhibitory concentration and minimum bactericidal concentration of 1.95 mg/ml and 7.81 mg/ml, respectively. The extract of B. ciliata showed synergistic activity with penicillin, oxacillin, ciprofloxacin, and clindamycin with a fractional inhibitory concentration index ≤ 0.5 against almost all the MRSA strains. A 16-fold reduction in MICs of oxacillin and penicillin was observed with a modulation factor value of 16, suggesting the possible antibiotic MIC reversal property of the tested extract. Gas chromatography-mass spectrometry investigation of the plant extract detected 17 phytocompounds. The study showed that Bergenia ciliata rhizome had the potential to change antibiotic resistance against MRSA by lowering the MIC of the antibiotics that were tested in combination with the extract.