Isolation and Identification of Clinical Bacterial Isolates and Their Resistance to Antibiotics and a Medicinal Plant Mixture (Turmeric, Ginger, and Indian Costus)

BackgroundThe rise of antibiotic resistance in Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) has intensified the search for natural antibacterial alternatives. This study evaluates the antibacterial efficacy of ethanolic (EE) and aqueous (AE) extracts from turmeric (Curcuma longa), ginger (Zingiber officinale), and Indian costus (Saussurea costus) against clinical isolates of S. aureus and E. coli. 
MethodA six-month laboratory-based study (April–September 2024) analyzed bacterial isolates from patient samples in Aden Governorate, Yemen. Isolates were identified using selective media Mannitol Salt Agar (MSA) for S. aureus, Eosin Methylene Blue Agar (EMB) for E. coli) and confirmed through biochemical tests. Antibacterial activity was assessed via agar well diffusion and minimum inhibitory concentration (MIC) assays. Phytochemical and physiochemical analyses identified active compounds in the extracts. 
ResultsOf 57 clinical samples, S. aureus was isolated from 52.63% and E. coli from 21.05%, while 26.32% were excluded due to contamination. The EE exhibited dose-dependent antibacterial activity against E. coli, with inhibition zones of 13–19 mm, but no activity against S. aureus. The AE showed no antibacterial effects. Antibiotic susceptibility testing revealed S. aureus was highly susceptible to Linezolid (96%) and Roxithromycin (96%) but resistant to Cloxacillin (0%). E. coli showed high resistance to Ampicillin/Sulbactam (57.14%) and Cefotaxime (55%) but susceptibility to Ciprofloxacin (90%) and Amikacin (95%).
ConclusionThe EE shows promise as a natural alternative for treating E. coli infections, particularly amid rising antibiotic resistance. However, its inefficacy against S. aureus highlights the need for further research to optimize extraction methods and enhance activity against Gram-positive bacteria. This study supports the potential of plant-based antimicrobials as alternatives to synthetic antibiotics.