In Vitro Antibacterial Properties of Aqueous Garlic Extract (AEG) Against Multidrug-Resistant Enterococci

Background : As relatively avirulent enteric bacteria, enterococci usually cause infections in immune-compromised patients. The antimicrobial treatment, however, is quite challenging, since enterococci are intrinsically resistant to many antibiotics. Objective of the present study was to examine the antibacterial activity of aqueous garlic extract on isolates of enterococci.
Materials and Methods : In this descriptive research, a total of 120 enterococcus isolates including 70 multidrug-resistant isolates causing different infections were collected from three hospitals in Zahedan. The susceptibility of isolates to different antibiotics was measured by agar diffusion test and antibacterial activity of garlic extract was measured using disc-diffusion and microbroth dilution methods.
Results : Among 120 enterococcus samples, 95 (79.2%) and 25 (20.8%) isolates were E. faecalis and E. faecium respectively. The highest resistance was observed in erythromycin (95.8%) and the lowest resistance (6.7%) in chloramphenicol, while 88.3% and 65.8% of the isolates were resistant to tetracycline and ampicillin respectively. Moreover, 58% of the isolates were Multi-Drug Resistant (MDR) and showed resistance to at least three antibiotics. Antibacterial activity of AGE was characterized by inhibition zones of 16.8±1.8 mm and Minimum Inhibitory Concentration (MIC) ranged from 4 to 32 mg/ml.
Conclusion : The present study suggests that AGE has a significant anti-enterococcal effect and therefore, supports the use of garlic as an herbal remedy in Zahedan.