AQU-1, a chromosomal class C β-lactamase, among clinical Aeromonas dhakensis isolates: Distribution and clinical significance
AQU-1, a chromosomal class C β-lactamase, among clinical Aeromonas dhakensis isolates: Distribution and clinical significance
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DOI：
10.1016/j.ijantimicag.2013.08.002
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发表时间：
2013-11-01
影响因子：
10.8
通讯作者：
Ko, Wen-Chien
中科院分区：
文献类型：
--
作者：
Wu, Chi-Jung;Wang, Hsuan-Chen;Ko, Wen-Chien
达肯气单胞菌 (Aeromonas dhakensis)，最近描述的一种气单胞菌。以前称为水族气单胞菌，与人类感染有关。在这项研究中，在达肯西斯 AAK1 中鉴定出了一个染色体基因 bla(AQU-1)，它构成了 1143 bp 的开放阅读框，与嗜水气单胞菌中编码 CepH 的基因有 87% 的一致性。携带bla(AQU-1)的大肠杆菌TOP10细胞转化体对头孢噻肟具有抗性，但对头孢吡肟没有抗性。头孢噻肟耐药突变株AAK1m中blaAQU-1的mRNA表达量比野生株AAK1高70倍。在所有 16 个达肯斯气单胞菌分离株（1999 年 6 月至 2001 年 6 月收集的 51 个连续气单胞菌血液分离株的主要种类）以及 A. aquariorum MDC47(T) 和 A. Hydrophila subsp. 中。 PCR 检测到 bla(AQU-1) 相关基因，但在其他嗜水气单胞菌亚种、豚鼠气单胞菌、维罗尼气单胞菌或肠表气单胞菌的参考菌株或临床分离株中未发现 dhakensis LMG 19562(T)。总体而言，16 个达肯斯不动杆菌血液分离株中的 13 个（81%）表现出头孢噻肟抗性或体外出现去抑制的头孢噻肟抗性突变体。在接受头孢噻肟单药治疗的烧伤患者中注意到达肯西斯不动杆菌抗性突变体的体内选择。这些观察结果表明，AQU-1 是达肯斯线虫中的一种染色体头孢菌素酶。头孢噻肟单药治疗重度达肯斯拉氏菌感染应谨慎使用。 (c) 2013 年 Elsevier B.V. 和国际化疗协会。版权所有。
Aeromonas dhakensis, a recently described Aeromonas sp. formerly called Aeromonas aquariorum, is associated with human infections. In this study, a chromosomal gene, bla(AQU-1), was identified in A. dhakensis AAK1 that constitutes a 1143-bp open reading frame and is 87% identical to the gene encoding CepH in Aeromonas hydrophila. An Escherichia coli TOP10 cell transformant harbouring bla(AQU-1) was resistant to cefotaxime but not to cefepime. mRNA expression of blaAQU-1 in the cefotaxime-resistant mutant strain AAK1m was 70-fold higher than in the wild strain AAK1. In all 16 A. dhakensis isolates (the major species of 51 consecutive Aeromonas blood isolates collected from June 1999 to June 2001) as well as in A. aquariorum MDC47(T) and A. hydrophila subsp. dhakensis LMG 19562(T), but not in the reference strains or clinical isolates of other A. hydrophila subspecies, Aeromonas caviae, Aeromonas veronii or Aeromonas enteropelogenes, bla(AQU-1)-related genes were detected by PCR. Overall, 13 (81%) of the 16 A. dhakensis blood isolates exhibited either cefotaxime resistance or the in vitro emergence of derepressed cefotaxime-resistant mutants. In vivo selection of an A. dhakensis resistant mutant was noted in a burn patient undergoing cefotaxime monotherapy. These observations suggest that AQU-1 is a chromosomal cephalosporinase in A. dhakensis. Cefotaxime monotherapy for severe A. dhakensis infections should be used cautiously. (c) 2013 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.