動物病院で診療を受けた,受診犬(27頭)及び受診猫(13頭),動物愛護センターで引き取られるか,捕獲された犬(20頭)及び猫(24頭),計84頭から分離された大腸菌776株について,ABPC,CP,CTC,KM,SM,NA,SAの7薬剤に対する感受性試験を行った。また耐性菌については,伝達性Rプラスミドの検索を行った。7薬剤のいずれかに耐性であった大腸菌は,犬では102株(24.7%),猫では59株(16.3%)であった。犬の耐性菌検出率では,受診犬(24.0%)と捕獲犬(25.5%)がほぼ同率であったが,猫では受診猫26.8%に対し,引取猫10.6%で,前者が高率であった。薬剤別の検出率は,犬ではCTC耐性が17.7%で最高,以下SA,SM,ABPC耐性の順であり,猫ではSA耐性が12.6%で最高,以下ABPC,CTC,SM耐性の順であった。捕獲犬は受診犬に比較して,すべての薬剤において検出率が高かったが,猫では逆にすべての薬剤で受診猫の方が引取猫より高かった。耐性型は,犬では単剤型から6剤型まで23種類(捕獲犬22種類,受診犬10種類),猫では単剤型から7剤型まで9種類(引取猫6種類,受診猫4種類)であった。受診犬は単剤型と2剤型で73%を占めたが,捕獲犬では3剤型以上が60%に達した。猫では,引取猫の過半数が単剤型と2剤型であったのに対し,受診猫は7剤型のみで62%を占めた。耐性菌における伝達性Rプラスミド保有菌の検出率は,犬が6.1%,猫が35.7%であった。猫では殆どが2剤伝達性であったが,犬では単剤伝達性が殆どであった。

Tests for sensitivity to seven drugs were conducted on 776 strains of Escherichia coli isolated from a total of 84 dogs and cats; 27 dogs and 13 cats referred to an animal hospital for treatment (referred group) and 20 dogs and 24 cats taken over or captured by animal protection centers (captured group). In the resistant strains, transferable R plasmid were studied. Resistance to at least one of the 7 drugs was found in 102 (24.7%) of strains obtained from dogs and 59 (16.3%) of strains obtained from cats. The percentage of resistant strains was 24.0% from referred dogs and 25.5% from captured dogs. The corresponding values were 26.8% in referred cats and 10.6% in captured cats. In dogs, the rate of resistance was the highest for CTC (17.7%) followed by SA, SM and ABPC in decreasing order. In cats, the rate of resistance was the highest for SA (12.6%) followed by ABPC, CTC and SM. The rate of drug resistance was higher for each drug in captured dogs than in referred dogs, but higher for each drug in referred cats than in captured cats. As to the range of multiple resistance, 23 combinations ranging from resistance to a single drug to 6 drugs were found in dogs (22 combinations in captured dogs and 10 combinations in referred dogs), whereas 9 combinations ranging from resistance to a single drug to all 7 drugs were found in cats (6 combinations in captured cats and 4 in referred cats). In referred dogs, resistance to 1 or 2 drugs accounted for 73%, whereas resistance to 3 or more drugs accounted for 60% in captured dogs. More than half of the strains from captured cats showed resistance to only 1 or 2 drugs, whereas strains resistant to all 7 drugs accounted for 62% from referred cats. Resistant strains with transferable R plasmid were found in 6.1% of dogs and 35.7% of cats. While 2 drug transfer was mostly found in cats, single drug transfer was mostly found in dogs.

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