In-vitro Antibacterial Activity of Hibiscus sabdariffa Calyx Extracts against Multidrug-resistant Escherichia coli from Patients with Urinary Tract Infections in Katsina State, Nigeria

Abstract

Background: Urinary tract infections (UTIs) are among the most prevalent bacterial infections globally, with Escherichia coli being the leading etiological agent. The increasing occurrence of multidrug-resistant (MDR) uropathogenic E. coli (UPEC) has significantly compromised the effectiveness of commonly used antibiotics, particularly in low- and middle-income countries. Aims: This study aimed to evaluate the antibacterial activity of aqueous and ethanol calyx extracts of Hibiscus sabdariffa against MDR E. coli isolated from patients with urinary tract infections attending General Hospital Dutsin-Ma, Katsina State, Nigeria. Method: Fifty midstream urine samples were collected and processed using standard culture, microscopy, and biochemical identification techniques. Antibiotic susceptibility testing was performed using the Kirby–Bauer disc diffusion method in accordance with Clinical and Laboratory Standards Institute guidelines. Phytochemical screening of H. sabdariffa extracts was conducted, and antibacterial activity was assessed using the agar well diffusion assay, followed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results: Ten (20%) E. coli isolates were recovered, with a higher prevalence among female patients (70%). High resistance rates were observed against cefotaxime (80%), ciprofloxacin (70%), and ampicillin (60%), while all isolates remained susceptible to nitrofurantoin (100%). Four isolates were classified as MDR. Both aqueous and ethanol extracts of H. sabdariffa demonstrated concentration-dependent antibacterial activity against MDR isolates, with the ethanol extract showing greater potency (MIC 25 mg/mL; MBC 50 mg/mL) compared to the aqueous extract (MIC 50 mg/mL; MBC 100 mg/mL). Conclusion: The findings indicate that H. sabdariffa possesses significant antibacterial activity against MDR UPEC and may serve as a potential complementary antimicrobial agent for urinary tract infections.