Antimicrobial effect of Xhantaria elegance sp. extracts on Brucella abortus and Brucella melitensis in vitro and in animal models

Brucellosis is one of the most common zoonosis diseases that caused by the intracellular bacteria of the genus Brucella. Most of human brucellosis agents are Brucella melitensis and Brucella abortus. The most effective antibiotic therapy for brucellosis is combination of doxycycline and rifampin. But this regime has disadvantages that include relapses and toxicity، especially in children and pregnant women. The aim of this study was to investigate the antimicrobial effect of lichen extracts on Brucella abortus and Brucella melitensis in vitro and animal models. firstly، the acetonic and ethanolic extracts of Xhantaria elegance prepared. Then the antimicrobial effect of extracts determined by well difusion method. Minimum inhibitory concentration (MIC) by macro dilution method. In animal model، each bacteia was inoculated intraperitoneally and after 24h، 0. 5 cc of each Xhantaria elegance SP extracts (as MBC concentration) inoculate i. p to BALB/c mice. Then، the counts of baceria in spleen culture were counted on agar media after 9 days. The results showed that the MIC of acetonic extract of lichen for Brucella abortus and Brucella melitensis was 217. 5 mg/ml and for ethanolic extract were 47 and 94 mg/ml، respectively. In animal models، the average number of bacteria grown in the test group than the control group showed a significant decrease. Acetonic extract has a greater effect than ethanolic extract and Brucella melitensis is more sensitive to the extracts.