The aim of this study was to determine antimicrobial susceptibility of Pseudomonas aeruginosa strains to marbofl oxacin and gentamicin, and investigate the possible synergistic, additive, indifferent or antagonistic effects between the two agents. P. aeruginosa strains can develop resistance quickly against certain antibiotics if used alone, thus the need emerges to fi nd synergistic combinations. A total of 68 P. aeruginosa strains isolated from dogs were examined. In order to describe interactions between marbofl oxacin and gentamicin the checkerboard microdilution method was utilized. The MICs (minimum inhibitory concentrations) for marbofl oxacin and gentamicin were in the range 0.25-64 mg/L and 0.25-32 mg/L, respectively. The combination of marbofl oxacin and gentamicin was more effective with a MIC range of 0.031-8 mg/L and a MIC 90 of 1 mg/L, compared to 16 mg/L for marbofl oxacin alone and 8 mg/L for gentamicin alone. The FIC (fractional inhibitory concentration) indices ranged from 0.0945 (pronounced synergy) to 1.0625 (indifference). Synergy between marbofl oxacin and gentamicin was found in 33 isolates. The mean FIC index is 0.546, which represents a partial synergistic/additive effect close to the full synergy threshold. In vitro results indicate that marbofl oxacin and gentamicin as partially synergistic agents may prove clinically useful in combination therapy against P. aeruginosa infections. Although marbofl oxacin is not used in the human practice, the interactions between fl uoroquinolones and aminoglycosides may have importance outside the veterinary fi eld.

The aim of this study was to investigate the effects of rosmarinic acid (RA) on a porcine, non-tumorigenic IPEC-J2 enterocyte cell line. The cell viability was tested with MTS assay and the transepithelial electrical resistance (TER) values were measured to determine the changes of the membrane integrity. The extracellular H2O2 production was analyzed with Amplex Red assay. The results show that the RA was not cytotoxic in low concentrations up to 100 µM. At 50 µM concentration RA promoted cell proliferation and did not cause significant increase in H2O2 production.