Antibiotic resistance among Escherichia coli urinary isolates and their susceptibility to clove essential oil

Escherichia coli is a Gram-negative, facultatively anaerobic, rod-shaped, coliform bacterium, which is a primary cause of urinary tract infections. Resistance to antibiotics has become a particular problem in recent decades. Consequently, there is an unmet need for new therapeutic options. It has been observed that essential oils have bactericidal effects. The antimicrobial susceptibility testing for Escherichia coli isolates obtained from urine of patients with urinary tract infections was determined via disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST, 2015). Essential oil from clove – Syzygium aromaticum (L.) Merill et L.M. (Myrtaceae) was analyzed by GC-FID-MS. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were detected by using the micro-dilution broth method. Escherichia coli clinical isolates are characterized by high resistance to ampicillin, amoxicillin with clavulanic acid, norfloxacin, trimethoprim/sulfamethoxazole, tetracycline, tobramycin and ticarcillin. Clove oil possesses strong inhibiting and killing properties against E. coli isolates, among them the ones resistant to recommended antibiotics. The results of this study highlight the need for testing the efficacy of new agents to inactivate bacteria in clinical settings.