Abstract
1) It was reported in the previous paper1) that antibacterial effect of Moenomycin was stronger for R+ strain than R- strain. In this study, the effect of Moenomycin to bacteria carrying R factor in the intestinal tracts of eels (Anguilla japonica) was investigated.
2) Experimental animals were fed with a test diet containing various amounts of Flavocorm-5G (containing 0.5% of Moenomycin) for successive 80 days. Gram negative-bacilli were isolated on drug-free nutrient agar or nutrient agar containing drugs (25 μg/ml of TC or CM) from intestinal tracts of the animals at the end of the experiment.
3) Among 90 strains of CM-resistant gram negative-bacilli isolated, 2 strains carried R factors. Among 100 strains isolated on drug-free nutrient agar, 6 carried R factors. However, among 100 strains of TC-resistant gram negative-bacilli isolated, the number of R factorcarrying strains were 64 (Table 2).
4) When comparing Moenomycin-free eel-group with Moenomycin-additive groups as regard the 64 R+ strains, it became clear that the number of bacteria carrying R factor decreased as the additive amounts of Moenomycin increased. Particularly the number of bacteria carrying R factor was remarkably small in the experimental group fed with a diet containing 50 ppm of Moenomycin.
5) From the above, it may be suggested that feeding of eels with a diet containing 50 ppm of Moenomycin decreases drug resistant bacteria carrying R factors from the intestinal tracts of the fish.
