The antimicrobial activity of root extracts of Zingiber Officinale on clinical isolates of Escherichia Coli and Staphylococcus Aureus

Abstract

The grievous outcomes of antimicrobial resistance (AMR) in society support the need for discovery of better alternative treatments to be used for infections management. Plants are known potential sources of antimicrobial agents therefore this study evaluated the antibacterial activity of Zinger officinale on clinical Escherichia coli and Staphylococcus aureus isolates. Aqueous and ethanolic extracts were obtained from fresh Z. officinale rhizomes. A total of 49 E. coli and 50 S. aureus isolates were tested with a panel of medically relevant drugs (trimethoprim sulphamethoxazole, neomycin, ampicillin, chloramphenicol, ciprofloxacin, gentamicin, ceftriaxone, doxycycline, penicillin and tetracycline) to establish the resistance patterns. A resazurin-based micro-broth dilution method was used to determine the minimum inhibition concentrations (MIC) of the extracts against the bacteria. The prevalence of multidrug resistance was higher in S. aureus (70%, n =35) compared to E. coli (59.2%, n =29). Escherichia coli had the lowest average MIC for both extracts (aqueous extract: 152.3mg/ml; ethanolic: 134.7mg/ml). Staphylococcus aureus had the highest mean MIC for both extracts (aqueous extracts: 198mg/ml; ethanol extract: 172.5mg/ml). The ethanolic extract demonstrated significantly better mean MIC results on E. coli than on S. aureus (p<0.05). The ethanolic extract was also found to contain terpenoids which were absent in aqueous extract. Both ethanol and aqueous extracts contained considerably similar quantities of flavonoids. The ethanolic extract was more effective than aqueous extract and E. coli was more tolerant to the extracts. Overall, Z. officinale is a promising candidate as an alternative to the conventional drugs to be used as therapeutic agent against clinical microbes.