2011年12月至2013年11月國立臺灣大學生物資源暨農學院附設動物醫院從狗與貓所分離出具廣效性乙內醯胺酶細菌株的分離率及特性分析

Abstract

自從1980年代初期，廣效性乙內醯胺酶已逐漸成為抗生素抗藥性領域研究的新課題。廣效性乙內醯胺酶可以抵抗乙內醯胺類抗生素並被乙內醯胺酶抑制劑抑制。研究顯示，大腸桿菌與肺炎克雷伯氏菌為最常見到的廣效性乙內醯胺酶產生菌株。近年各國研究均指出帶有廣效性乙內醯胺酶的菌株分離率正逐漸增加，而且傳播型態也逐漸改變。相對而言，台灣在伴侶動物所分離的菌株是否帶有廣效性乙內醯胺酶及其特性等相關資訊則較有限。 本研究之目的在於檢查並分析由2011年12月至2013年11月間，由國立臺灣大學生物資源暨農學院附設動物醫院從犬貓所分離到的臨床菌株是否帶有廣效性乙內醯胺酶及細菌的相關性狀分析。依照美國臨床和實驗室標準學會 (CLSI)之雙紙錠協同測試法確認步驟進行廣效性乙內醯胺酶表現型偵測。研究結果顯示465株菌株中共有60株細菌偵測到表現廣效性乙內醯胺酶性狀。這裡面包含了26株大腸桿菌、16株肺炎克雷伯氏菌、10株腸桿菌屬細菌、3株不動桿菌屬細菌、3株沙雷氏菌屬細菌與2株綠膿桿菌。整體菌株之廣效性乙內醯胺酶分離率為12.9%。TEM和CTX-M是最主要的廣效性乙內醯胺酶基因型，在CTX-M的次分型中則以CTX-M-1次分群最常見。多基因位點序列分析結果顯示在可產生廣效性乙內醯胺酶的大腸桿菌中最常分離到的序列型為ST457。 研究結果顯示在國立臺灣大學生物資源暨農學院附設動物醫院的伴侶動物廣效性乙內醯胺酶的分離率是相對高於西方國家的，抗藥性的增加也暗示著在臨床治療上的困難。基因分型和多基因位點序列分析結果皆顯示在台灣伴侶動物廣效性乙內醯胺酶與人醫之間的差異。本結果僅代表國立臺灣大學生物資源暨農學院附設動物醫院之伴侶動物中廣效性乙內醯胺酶流行病學研究結果，無法代表台灣整體伴侶動物的廣效性乙內醯胺酶流行病學研究結果。

Since the early 1980s, extended-spectrum β-lactamases (ESBLs) had become an emerging issue for antibiotic resistance. Production of ESBL confers resistance to the commonly used beta-lactam antimicrobials, but are inhibited by β-lactamases inhibitors. Escherichia coli and Klebsiella pneumoniae are the two major ESBL-producing bacteria. Several studies have revealed that the ESBL prevalence around the world is increasing in recent years, and the transmission route is changed. On the contrary, the isolation rates of resistance to ESBL among microorganisms from companion animals remained limited in Taiwan. The objective of the present study was to examine and characterize the occurrence of ESBL-producing microorganisms in clinical samples of dogs/cats attending to National Taiwan University Veterinary Hospital (NTUVH) during December 2011 to November 2013. Combination disc tests using cefotaxime and ceftazidime (30 μg) disks, with and without clavulanic acid (10 μg) according to CLSI guidelines resulted in 60 isolates demonstrating an ESBL phenotype from 465 isolates included in this study. Twenty-six Escherichia coli, 16 Klebsiella pneumoniae, 10 Enterobacter spp., 3 Acinetobacter spp., 3 Serratia spp, and 2 Pseudomonas aeruginosa isolates exhibited ESBL phenotype. The ESBL prevalence was 12.9%. TEM and CTX-M were the two major ESBL genes, while CTX-M-1 was the most commonly found subgroup in CTX-M subtyping. Multilocus sequence typing (MLST) revealed that ST457 was the predominant sequence type in ESBL-producing E. coli. Our result showed that the isolation rate of ESBL in NTUVH is comparatively higher than that from western countries. Increase of drug resistance may indicate the treatment difficulty in clinical practice. Gene typing and MLST results both showed the difference between human and companion animals in ESBL. Our results only represent the epidemiology of ESBL-producing bacteria from the companion animals in NTUVH, not the whole Taiwan’s companion animals.