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The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus >
No.32 (1985/12) >

 
Title :子豚ふん便由来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 of Escherichia coli isolated from piglet feces (Department of Animal Science)
Authors :日越, 博信
猪俣, 隆一
Authors alternative :Higoshi, Hironobu
Inomata, Ryuichi
Issue Date :2-Dec-1985
Abstract :沖縄県における家畜由来細菌の薬剤耐性の動向を知る目的で, 一養豚場の子豚(日齢によって4期に分け, 各40頭)及び子豚I期, II期の母豚10頭の直腸ふん便から大腸菌を分離した。これらについてAM, CTC, SM, CP, KM及びSAに対する薬剤感受性試験を行うとともに, Rプラスミドの検出を行った。子豚のI期(5∿6日齢)98株, II期(14∿15日齢)91株, III期(25∿29日齢)102株, IV期(51∿56日齢)102株, 母豚44株, 合計437株中406株(92.9%)がいずれか1剤に耐性であった。耐性菌の検出率は, 子豚ではI期が83.7%, II期以降が100%と高率であったが, 母豚では65.9%であった。薬剤別の耐性菌の検出率は, SAが86.7%で最高, 次いでCTC83.1%, SM49.4%の順であった。SA耐性菌は, 子豚では日齢が進むほど高く, CTC耐性菌はII期以降急に高くなり, またSM耐性菌はI期で高く, II期以降やや低くなった。母豚では, SM耐性菌が子豚II期以降とほぼ同じであったが, 他はいずれも低率であった。耐性型は, 25種類認められたが, 2剤耐性が33.5%で最高, 以下4剤耐性, 3剤耐性の順であった。耐性型別ではCTC-SA, CTC-SM-SA, AM-CTC-SM-SA耐性型が多かった。耐性菌のうちR^+菌は17.7%であった。このR^+菌の検出率は, 子豚I期が31.7%で最も高く, 日齢が進むほど低くなり, また母豚では6.9%であった。R^+菌の伝達耐性型は, AM及びSAの1剤が多かったが, これらの薬剤を含む4剤型, 5剤型もみられた。なお, 子豚由来大腸菌の薬剤耐性型と母豚由来大腸菌のそれとは関連ずけられなかった。
Escherichia coli isolates from rectal fecal specimens collected from 40 piglets (classified into four stages according to age) and 10 sows nursing stage I-II farrows at a hog farm were studied to explore trends of drug resistance acquired by bacteria in domestic animals in Okinawa Prefecture. The organisms were tested for susceptibility to such drugs as AM, CTC, SM, CP, KM and SA and examined for R plasmids. Of a total of 437 strains of E. coli, i.e. 98 strains from stage I piglets (5-6 days of age), 91 from stage II piglets (14-15 days), 102 from stage III piglets (25-29 days), 102 from stage IV pglets (51-56 days) and 44 from sows; 406 strains (92.9%) were found to be resistant to at least one of these antibiotics. Percentages of the resistant isolates were noticeably high in piglets (83.7% in the stage I and 100% in stage II-IV) whereas the isolates from sows showed a resistance rate of 65.9%. The greatest proportion (86.7%) of the E. coli isolates showed resistance to SA, followed, in order, by CTC (81.3%) and SM (49.4%). The percentage of SA-resistant strains in farrows increased progressively with advancing age, and that of CTC-resistant strains rose sharply from stage II onwards. SM-resistant strains were frequent at stage I and declined slighly as stages II-IV. In sows, SM-resistant organisms were isolated with essentially the same frequency as those in stage II piglets whereas percentages of isolates resistant to the rest of the drugs were low. There were 25 cross resistance patterns with the present series of E. coli isolates from porcine feces. Strains resistant to two drugs were most frequent, 33.5%, followed, in order, by those resistant to four drugs and to three drugs. Most commonly encountered were strains showing resistance to combinations of CTC-SA, CTC-SM-SA, or AM-CTC-SM-SA. Of all the drug-resistant strains studied, 17.7% were positive for R plasmids. The R plasmid positivity rate was highest with the isolates from stage I piglets (31.7%) and diminished with advancing age, being 6.9% with those from sows. Drug resistance via transferable R plasmids was most frequent to AM or SA alone while patterne of resistance to 4 or 5 drugs including either or both of these drugs were also encountered. Interrelation between the drug resistance patterns of the E. coli isolates from farrows and those of isolates from nursing sows remains unclear.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3947
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.32 p.133 -141
Appears in Collections:No.32 (1985/12)

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