RESUMO
Although modern medicine has definite advantages compared with traditional medicine, one of its important problems is overuse of chemical drugs that leads to drug resistance and side effects. This study was conducted to compare effects of Glycyrrhiza glabra with nalidixic acid and nitrofurantoin on bacteria isolated from patients with urinary tract infections and renal calculi. This experimental study was done on 100 patients. Glycyrrhiza glabra extract was taken from the rizhome of 3- or 4- year herb by perculation with methanol 85%. Solvent was vaporized and lyophilized. Antibacterial effects of the herb extract, nitrofurantoin and nalidixic acid were evaluated by two methods of disc diffusion and MIC. Statistical analysis was performed by ANOVA and paired t- test. In disc diffusion, 100% of Streptococcus and MRSA and 33% of E.coli were susceptible to Glycyrrhiza glabra extract. In testing for MIC, Streptococcus, MRSA, Enterococcus fecalis in 1:128 dilution, and E.coli were susceptible in 1:64 dilution of Glycyrrhiza glabra extract. Klebsiella, Serattia, and Entrococcus facium were resistant. Diameter of no growth of bacteria among gram positive and negative bacteria were significantly different in Glycyrrhiza glabra extract and nitrofurantoin groups [p<0.05], and was non significantly different in nalidixic acid group [p=0.9]. It seems that Glycyrrhiza glabra extract can be used in combination with antibiotics for the treatment of urinary tract infections