Chun Nam Cha

Antibacterial Effects of Galla Rhois Extract against Streptococcus suis Infection in Mice

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent and is an increasing public health problem across Asia. The present study was undertaken to estimate the antibacterial effect of GR extract and therapeutic effect of GR extract against S. suis infection in mice. At the concentration of GR extract 2.5 mg/ml, the antibacterial effect was not shown on S. suis. However, the antibacterial effect against S. suis was observed at the concentration of GR extract 5.0 mg/ml. Oral administration of GR extract at the dose of 10 mg/kg showed a therapeutic effect for S. suis infected BALB/c mice. The mortality of GR extract-treated mice at the concentration of 5, 10 and 20 mg/kg was 80%, 70%, and 50% at 12 days, respectively, while that of untreated mice was 100% at 8 days after a lethal dose of S. suis infection. The results of our study strongly indicate that GR extract has potential as an effective for S. suis infection in mice.

Application of a Lateral Flow Immunoassay to Determine Ampicillin Residues in Muscle Tissue of Olive Flounder (Paralichthys olivaceus)

Antibiotic Detection Kit (Combination I), a lateral flow immunoassay (LFIA) developed for the detection of antibiotic residues in milk, was utilized for the analysis of antibiotic residues in the muscle tissue of olive flounder. After 60-min treatment by dipping in water dosed with ampicillin (200-g/ton water), the residue depletion of ampicillin was investigated in 25 cultured olive flounder (Paralichthys olivaceus). Muscles of fish were sampled on the 1st, 2nd, 3rd, 4th and 5th day after drug treatment. The concentration of ampicillin in the muscle was determined by LFIA. The absorbance ratio of the sample to the control blank (Bs/Bo) was employed as an index to determine the muscle residues in olive flounder. To investigate the recovery rate, standard solutions were added to muscle samples to give final concentrations in the muscle of 4 and 8 ng/ml. The recovery rates of all spiked samples were > 96% of the spiked value. Ampicillin was detected in the muscle of fish treated with the drug until the 2nd day of the with- drawal period. The present study showed that the LFIA can be easily adopted to predict ampicillin residues in tissue of farmed fishes.