| 摘要: | 本研究的目的是對Pseudomonas aeruginosa產生抗藥性菌株進行盛行率的研究。針對100株非重複分離之綠膿桿菌進行大規模的藥物敏感性偵測。在抗生素感受性試驗中，發現這些分離株的抗藥性對ampicillin/sulbactam為100%，對bacitracin也達到98%。對廣效性頭孢子黴素類的抗藥素cefotaxime 達39% 具有抗藥性。從抗藥性篩選中發現其中有8株P. aeruginosa對cefotaxime、ceftazidime、carbapenems、fluoroquinolones、aminoglycosides、ampicillin/sulbactam、timentin、bacitracin、kanamycin 及 tetracycline 都不具有感受性，因此為多重抗藥性菌株。利用脈衝式電泳以 SpeI 限制酶將 8 株P. aeruginosa作分子分型，結果顯示這些菌株均為不同的 pulsotypes。由瓊脂紙錠藥物敏感試驗、雙紙錠協同測試法、瓊脂稀釋試驗法、修飾雙紙錠測試法、最小抑菌濃度(E-test)、等電點聚焦電泳，鑑定P. aeruginosa可能產生的乙內醯胺酶，結果顯示8株P. aeruginosa都帶有超過一種以上的乙內醯胺酶。進行電孔法實驗、聚合酶連鎖反應和DNA序列分析顯示這些菌株的質體上皆帶有pI 6.3 一個胺基酸變異的OXA-10 class D乙內醯胺酶，由於胺基酸的改變我們將它命名為OXA-10 like 乙內醯胺酶。實驗中也發現嵌入子帶有許多不同型式基因片匣，而這些基因片匣包含了chloroamphenicol、aminoglysides 和 refampin抗藥基因。本研究首先發現blaOXA-10 like 乙內醯胺酶和一些新的 aminoglycoside 抗藥基因分別為aadA15、 aac(6’)-Pa79。由此顯示抗藥性菌株於抗生素篩選性壓力下和多種class 1 integron 存在下，散播多重抗藥基因所造成的威脅。
The main purposes of the present study were to investigate the prevalence of Pseudomonas aeruginosa producing drug resistant factors. On the basis of these findings a large-scale surveillance effort for antibiotic susceptible detection among 100 non-repetitive isolates of P. aeruginosa were undergone. The greatest prevalence of resistance of these isolates was seen for ampicillin/sulbactam (100%), and bacitracin (98%). Resistance rates among ceplalosporin were highest for cefotaxime (39%). We also found multiple antibiotic resistant P. aeruginosa in eight strains that were not susceptible to cefotaxime, ceftazidime, carbapenems, fluoroquinolones, aminoglycosides, ampicillin/sulbactam, timentin, bacitracin, tetracycline and cefepime. All of these strains with different pulsotypes were classified by SpeI Pulse Field Gel Electrophoresis (PFGE) patterns. To identify the potential of β-lactamases-producing P. aeruginosa strains were examined with disc diffusion, double disc methods, agar dilution test, modification double-disc test, the β-lactamase E test and IEF, revealing all strains possessed more than one β-lactamases. Electrotransformation, PCR assays specific for various bla genes, and DNA sequencing revealed that these strains in plasmid all encoded a pI 6.3 variant OXA-10 class D β-lactamase by a amino acid substitution named OXA-10 like β-lactamase. There were different types of gene cassette including chloroamphenicol, aminoglysides and refampin resistant genes that were located in integron. In our study, the ß-lactamase gene blaOXA-10 like and some new aminoglycoside resistance gene aadA15 and aac(6’)-Pa79 were first found, indicating the selective pressure were threats in Taiwan. The resistance gene dissemination by class 1 integron also found in these strains in this study. |
