양식뱀장어에서 분리한 Edwardsiella tarda의 약제 내성과 R Plasmid

Drug Resistance and R Plasmids in Edwardsiella tarda from Cultured-Eel

A total 41 strains of Edwardsiella tarda were isolated from cultured eels and examined for drug resistance, distribution and transferabilities of R plasm ids. All isolates were multiple- resistant to drugs(at least 4 among 13 drugs) and mostly restricted to LM(41 strains), SD(41 strains), CH(39 strains), SF(38 strains), CP(37 strans), PM(37 strains), OT(36 strains), SM(29 strains), OA(29 strains), AM(28 strains), KM(7 strains), GM(6 strains), AK(6 strains) and EF(2 strains). Twentyfive different drug resistant patterns were observed, the most frequently encountered pattern was LM - SD - CH - SF - CP - PM- OT - SM - OA (8 strains, 20 %) followed by LM-SO-CH-SF-CP-PM-SM-OA(5 strains, 12%). In transfer experiment, transferable R plasm ids were carried in 39 of 41 resistant strains, indicating that most isolates carried conjugally transfer able R plasm ids related to multiple drugs. The most frequently observed transferable R plasm ids were SO-SF-CP-CH-LM-PM-AM (4 strains), SO-CP-CH-LM-PM-AM-OT(3 strains), SD-SF-CP-CH-LM-PM(3 strains) and SD-SF(3 strains). These results suggest that the chemotherapy of edwardsiellosis is extremely difficult because of the acquirement of multi-drug resistance to wide range of antibacterials. Futhermore it seems that high levels of various chemotherapeutics have already been introduced to eel culture.