Antibacterial effect of some aqueous plant extracts against multidrug-resistant bacterial strains

The problem of antibiotic-resistant bacteria is a serious problem all over the world and needs improved alternative treatment methods. For this study, four strains of pathogenic bacteria, Pseudomonas aerogenosa, Escherichia coli, Streptococcus pyogenes, and Staphylococcus aureus, were subjected to the inhibitory activity of seven plant extracts in aqueous form: Garlic, Pomegranate peels, Anise, Clove, Honey, Curcumin, and Mint. The results were compared with the activity of twelve antibiotics. The results indicated that Gram-positive bacteria were generally more susceptible than Gram-negative bacteria, and the only exception to this was Escherichia coli that was treated with pomegranate peel extract. Another important finding of the study was the rising bacterial resistance rate, threatening the use of traditional antibiotics. These results varied greatly in the sensitivity of the isolates, ranging from total resistance to cefixime, oxacillin, and penicillin. The natural extracts, however, showed a higher inhibitory activity and, in some cases more effective than conventional antibiotics. Among all the tested bacteria, Escherichia coli was found to be most resistant to Sulfa antibiotics, but the most susceptible to the largest zone of inhibition (40 mm) of the pomegranate peel extract. The extract of clove also exhibited broad spectrum activity with an inhibition zone of 36 mm gram-3 with respect to S. pyogenes. The study reveals that the aqueous extracts, particularly from pomegranate peels, cloves, and honey, are potential natural alternatives for combating drug-resistant bacterial strains.