台灣地區雞及鴿隻鳥鼻氣管桿菌之分離鑑定、16S rRNA序列分析、抗體盛行率暨抗菌劑感受性調查

Abstract

摘要 鳥鼻氣管桿菌 (Ornithobacterium rhinotracheale, ORT) 為一新興之多形性革蘭氏陰性桿菌，主要造成家禽呼吸道疾病，可導致病禽生長遲緩、產蛋率下降，甚至死亡等損失，影響家禽產業甚鉅。ORT在國內之研究甚少，故本研究由雞及鴿氣管中分離病原，並進行生化鑑定、抗菌劑感受性試驗、序列分析及抗體調查。結果顯示，由雞及鴿隻所採集之樣本中，其分離率分別為8.3 % (28/337) 及9 % (12/133)。所有ORT分離株 (40/40) 在API 20NE鑑定系統之生化結果全部一致，生物碼為0-0-2-0-0-0-4。對於alkaline phosphatase、esterase (C4)、esterase lipase (C8)、leucine arylamidase、acid phosphatase、oxidase等酵素反應皆為陽性，而MacConkey、SIM、TSI、catalase、lysine、ornithine、phenylalanine、surcose、sorbitol及dulcitol等生化試驗則全部為陰性反應。各分離株經瓊脂稀釋法進行12種抗菌劑之感受性試驗後，發現大多數分離株(>70%)對於trimethoprim-sulfamethoxazole、erythromycin 及clindamycin有高比例之抵抗性，對ampicillin、amoxicillin、penicillin及ceftiofur則有較佳之感受性 (>85%)。將分離株16S rRNA之PCR產物經定序並與由GenBank所得序列比對後，得知在不同分離株間其核苷酸相似度極高 (98.0~100%) ，但由親緣樹狀圖仍可發現鴿與雞之分離株分屬於不同的群組。在血清學方面，利用市售ELISA 套組檢測白肉雞、有色雞、蛋雞及種雞之ORT抗體，其陽性率分別為29.7% (221/745)、60.7% (403/664)、70.3% (204/290) 及93.9% (341/363)。本論文為台灣雞及鴿隻ORT分離首報，調查結果顯示台灣地區之鳥禽已普遍有ORT感染。

Abstract Ornithobacterium rhinotracheale (ORT), a newly recognized pathogen, is associated with respiratory diseases in avian species. To date, little is known about ORT infection in Taiwan. Therefore, tracheal swabs and serum samples were collected from the chickens and pigeons for the isolation, biochemical characteristics, antimicrobial susceptibility, sequence analysis, and antibody survey of ORT. The results showed that the ORT isolation rate of chickens and pigeons were 8.3 % (28/337) and 9 % (12/133), respectively. The identical results of biocode 0-0-2-0-0-0-4 were observed in all the isolates using API 20NE identification system. These isolates showed positive results in alkaline phosphatase (C4), estrase lipase (C8), leucine arylamidase, acid phosphatase, and oxidase reactions, but negative to MacConkey, SIM, TSI, catalase, lysine, ornithine, phenylalanine, sucrose, sorbitol, and dulcitol reactions. Most isolates (>70%) were resistant to trimethoprim-sulfamethoxazole, erythromycin, and clindamycin, but susceptible to ampicillin, amoxicillin, penicillin, and ceftiofur (>85%) by agar disc diffusion method. As for the analysis of 16S rRNA sequence, high similarities (98–100%) were revealed among the isolates in this study and the previously published sequence data. The chicken and pigeon isolates were divided into different clusters in phylogenetic tree. By using commercial ELISA kits, the antibody positive rates of broilers, hybrid broilers, layers, and breeders were 29.7% (221/745), 60.7% (403/664), 70.3% (204/290), and 93.9% (341/363), respectively. To our knowledge, this is the first report of the isolation of ORT from chickens and pigeons in Taiwan, and the results indicated that ORT infection is common in Taiwan. Abbreviations: SIM, sulfide-indole-motility; TSI, triple sugar iron; ELISA, enzyme-linked immunosorbeat assay.