Studies of Drug Resistance and R Factors in Bacteria from Pond-Cultured Salmonids
II.Rainbow trout (Salmo gairdneri f. irideus)
1973 Volume 8 Issue 1 Pages 83-90
Details
1973 Volume 8 Issue 1 Pages 83-90
Various drug resistant bacteria were isolated from the ponds-water and the intestinal tracts of rainbow trout (Salmo gairdneri f. irideus) obtained at Okutama in Tokyo Metropolis, at Fujinomiya in Shizuoka Prefecture and at Akashina in Nagano Prefecture from December, 1970 to June, 1971. Drug resistance patterns of isolated bacteria and whether or not their resistance is due to R factors were investigated. Resistance patterns and fi type of R factors isolated from these bacteria were tested.
1) The multiple-drug-resistant gram-negative bacilli were isolated from the water of ponds as well as from the intestinal tracts of rainbow trout.
2) The frequency of occurrence of drug resistant bacteria isolated from the rainbow trout pond was varible from pond to pond. The average percentages of chloramphenicol (CM)- and tetracycline (TC)- resistant bacteria (grown on nutrient agar containing 25μg/ml of CM or TC) isolated from the ponds water were 7.9 and 5.0, respectively and those from the intestinal tracts of rainbow trouts were 1.5 and 22.1, respectively.
3) Fairly low proportions of drug resistant bacteria that is, 4 out of the 188 strains examined (2.1%) were found to carry transferable R factors.
4) Considerable fractions of strains of, Achromobacter, Citrobacter, Enterobacter aerogenes, E. cloacae, Hafnia, Pseudomonas, Vibrio and unidentified Enterobacteriaceae isolated from the ponds-water and the intestinal tracts of rainbow trout were drug resistant and some of the drug resistant strains of Citrobacter, E. aerogenes and E. cloacae were found to carry R factors.
5) All the R factors detected had markers resistance to sulfonamides, streptomycin and TC and classified into fi- type.
