School of Molecular Bioscience, The University of Sydney, NSW 2006, Australia.
J Antimicrob Chemother. 2011 Jul;66(7):1504-9. doi: 10.1093/jac/dkr163. Epub 2011 May 17.
To examine the distribution and context of aminoglycoside resistance genes in multiply antibiotic-resistant Acinetobacter baumannii isolates from Australia that are members of the global clone 2 and carry the bla(OXA-23) gene conferring resistance to carbapenems.
Sixty-one multiply antibiotic-resistant A. baumannii strains isolated between 2000 and 2010 at six Australian hospitals that belonged to global clone 2 and carried the bla(OXA-23) gene were studied. Various molecular techniques were used to determine their relatedness and to detect antibiotic resistance genes and insertion sequences. Structures surrounding the aminoglycoside resistance genes were sequenced.
The isolates all shared several antibiotic resistance genes, including the sul2 sulphonamide resistance gene, but varied in their pattern of resistance to aminoglycosides. The aminoglycoside resistance profiles of isolates were accounted for by four resistance genes-aadB, aacC1, aphA1b and aphA6-in various combinations. The aadB gene cassette was located at a secondary site on a 6 kb plasmid similar to pRAY. The aphA6 gene was in a transposon, TnaphA6, bounded by directly oriented copies of ISAba125. The aacC1 gene cassette in a class 1 integron and Tn6020 carrying aphA1b were always present together, but were not linked.
Imipenem-resistant global clone 2 A. baumannii isolates containing bla(OXA-23) have been present in Australian hospitals for at least 10 years. Variation in this global clone 2 type has occurred with the introduction of various aminoglycoside resistance genes carried on a small plasmid or within transposons.
研究来自澳大利亚的对多种抗生素耐药的鲍曼不动杆菌分离株中氨基糖苷类耐药基因的分布和情况，这些分离株属于全球克隆 2 型，携带 bla(OXA-23)基因，对碳青霉烯类抗生素具有耐药性。
对 2000 年至 2010 年间澳大利亚六家医院分离的 61 株属于全球克隆 2 型且携带 bla(OXA-23)基因的多重耐药鲍曼不动杆菌进行研究。使用各种分子技术来确定它们的亲缘关系，并检测抗生素耐药基因和插入序列。对氨基糖苷类耐药基因周围的结构进行测序。
这些分离株均携带几种抗生素耐药基因，包括 sul2 磺胺类耐药基因，但对氨基糖苷类的耐药模式存在差异。分离株的氨基糖苷类耐药谱由 aadB、aacC1、aphA1b 和 aphA6 四个耐药基因以不同组合构成。aadB 基因盒位于与 pRAY 相似的 6kb 质粒的次要位置。aphA6 基因位于转座子 TnaphA6 中，由同向排列的 ISAba125 直接包围。位于 1 类整合子中的 aacC1 基因盒和携带 aphA1b 的 Tn6020 总是同时存在，但没有连接。
携带 bla(OXA-23)的耐亚胺培南全球克隆 2 型鲍曼不动杆菌分离株已在澳大利亚医院存在至少 10 年。该全球克隆 2 型的变异是通过引入各种携带在小质粒或转座子上的氨基糖苷类耐药基因引起的。
