Background & Objectives: Brucellosis is an infectious disease caused by intracellular pathogens of the genus Brucella that have their natural reservoir in domestic and wild animals. Many studies show that herbal medicines have been used safely and successfully to treat bacterial diseases without significant side effects and drug resistance problems.

  Methods: In this study aquatic, alcoholic and acetonic extracts of Eucalyptus globulus leaves were prepared, then MIC and MBC of extracts for B. melitensis 16M and B. abortus S99 were determined by broth macrodilution and agar well diffusion methods. In animal model study, 5 × 10⁵ CFU/mL of Brucellae was injected intraperitoneally (i.p) to female BALB/c mice. After 24 hours, 0.5mL (equivalent MBC) of each Eucalyptus globulus extracts was injected (i.p) After 7 days, in spleen the colonies of brucellae were counted on Muller-Hinton agar as standard protocol. 

  Results: The MIC and MBC of Eucalyptus globulus for B. melitensis M16 and B. abortus S99 were 1:80 (10.81 mg/mL) and 1:40 (21.62 mg/mL) for aquatic extract, 1:1280 (0.64 mg/mL) and 1:640 (1.29 mg/mL) for acetonic extract, and 1:2560 (0.31 mg/mL) and 1:1280 (0.63 mg/mL), for ethanolic extract respectively. In culture of spleen supernatant (in vivo), after 48 hours, the average grown B. melitensis 16M colonies for aquatic, ethanolic and acetonic extracts were 5×10³ CFU/ml, 2×10² CFU/ml and 6×10² CFU/ml, respectively in comparison with control group (4×10¹⁰ CFU/ml). These results for B.abortus S99 were 3×10³ CFU/ml, 1×10² CFU/ml and 3×10² CFU/ml, respectively in comparison with control group (9×10⁹ CFU/ml) The results showed that bacterial load was significantly decreased in all experimental groups (p<0.01). 

  Conclusion : The results of in vitro and in vivo indicate that ethanolic and acetonic extracts of Eucalyptus globulus have more effective antimicrobial activity on B.melitensis M16 and B.abortus S99 than aquatic extract. It seems that the extracts Eucalyptus globulus can be used in treatment of human and animal brucellosis.

  Background & objectives: Yersiniosis is created by Yersinia enterocolitica O:8 and causes problems in the world especialy in cold and mild countries. The purpose of this study is to evaluate the immunogenicity of Yersinia enterocolitica O:8 oligopolysaccaride (OPS) conjugate to diphtheria toxoid (DT) as a vaccine candidate.

  Methods : After cultivation of bacteria, the LPS were isolated by modified hot phenol method. Then dialysis and concentration were done and the OPS were extracted by acetic acid 2%. To conjugate with diphtheria toxoid, ADH was used as a spacer molecule and EDAC as a linker. Conjugate was purified by gel filtration. Then 4 groups of female BALB/c mice were selected (15 mice in each group). Injection was performed intraperitoneally in three doses with two weeks interval. Then serum samples were collected and antibody response against OPS was measured by indirect ELISA method for detection of total IgG, IgA, IgM, IgG1, IgG2a, IgG2b and IgG3.

  Results: After second and third doses, OPS-DT recieved group showed significant increase in all types of antibodies titer in anti-OPS in comparison to group that recived nonconjugated OPS. The increase in titer of antibodies was as: OPS-DT>OPS>DT. A remarkable increase was shown in total IgG and IgM titers (with total amount of 3204 and 670, respectively). In IgG1 subclass the amount was 920 and in other subclasses of IgG (IgG3, IgG2a and IgG2b) the amounts were 910, 110, and 99, respectively.

  Conclusion: The results shows that OPS of Yersinia enterocolitica O:8 increases the anti-OPS antibodies in the form of conjugate with diphtheria toxoid and could be considered as an appropriate vaccine candidate.