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No.31 (1984/11) >

Title :乳牛の分房乳から分離された大腸菌の薬剤耐性と R プラスミド(畜産学科)
Title alternative :Drug resistance and R plasmids in Escherichia coli isolated from milk obtained from each quarter of the udder of milk cows (Department of Animal Science)
Authors :日越, 博信
藤沢, 倫彦
高田, 潤一
Authors alternative :Higoshi, Hironobu
Fujisawa, Tomohiko
Takada, Junichi
Issue Date :19-Nov-1984
Abstract :沖縄本島南部地区(201頭, 780試料)および北部地区(148頭, 575試料)における乳牛の分房乳から分離した大腸菌, 南部地区31株, 北部地区61株, 合計92株を対象にAM, CP, CTC, KM, SMおよびSAの6薬剤を用いて薬剤感受性試験を行うとともに, 耐性菌についてはRプラスミドの検索を行った。分房乳における大腸菌の検出率は, 南部地区2.1%(16試料), 北部地区3.8%(22試料)であり, 意外に低率であった。各薬剤に対する耐性限界値をSAでは200μg/ml, 他の5薬剤では25μg/mlとすると, 全供試菌株がいずれか1剤に耐性であった。薬剤別には両地区ともSA耐性が多かったが, 次いでは南部地区がAM, SM耐性であり, 北部地区がSM, CTC耐性であった。耐性型は, 北部地区ではSA単剤耐性が86.9%を占め, 多剤耐性菌が少なかった。南部地区における耐性型は, SA単剤耐性が38.7%で最も多く, 次いでは5剤耐性の32.3%, 4剤耐性の16.1%であり, 北部地区に比較して多剤耐性菌の出現率が高かった。耐性菌におけるRプラスミドの保有率は, 南部地区41.9%, 北部地区14.8%であり, 前者地区で高率であった。Rプラスミドの伝達耐性型は, 両地区ともSA単剤伝達耐性型が多かったが, 2剤および3剤伝達耐性型も検出された。また, 2剤および3剤伝達耐性型のRプラスミドは, SAをその伝達耐性型の1部にしていた。
E. coli were isolated from milk produced by dairy cows in the southern district (780 samples from 201 cows) and northern district (575 samples from 148 cows) of Okinawa. 31 strains from the southern district and 61 strains from the northern district, a tortal of 92 strains were studied. Along with drug sensitivity tests using AM, CP, CTC, KM, SM, and SA, R plasmid was investigated in drug-resistant strains. The frequency of detection of E. coli in the quarter milk was 2.1% in the southern district (16 samples) and 3.8% in the northern district (22 samples), both unexpectedly low. When the limiting value of resistance against each drug was set at 200μg/ml for SA and 25μg/ml for 5 other drugs, all test bacteria were resistant to one or more drugs. Resistance to SA was most frequently seen in both districts, followed by resistance to AM and SM in the southern district, and resistance to SM and CTC in the northern district. According to the resistance pattern, resistance to SA alone occupied 86.9% in the northern district, with less frequent multiple resistant strains. In the southern district, resistace to SA alone was seen most frequently in 38.7%, followed by resistance to 5 drugs, 32.3% and resistance to 4 drugs in 16.1%. Compared to the northern district, multiple resistant strains were more frequently detected. Prevalence of R plasmid in the resistant bacteria was 41.9% in the southern district and 14.8% in the northern district. The transmitted resistance pattern of R plasmid was most frequently for SA alone in both districts, but transmitted resistance to 2 or 3 drugs was also detected. R plasmid of transmitted resistance to 2∿3 drugs contained transmitted resistance to SA in addition.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3972
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.31 p.111 -117
Appears in Collections:No.31 (1984/11)

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