Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China.
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, PR China.
J Med Microbiol. 2014 Mar;63(Pt 3):386-392. doi: 10.1099/jmm.0.069427-0. Epub 2014 Jan 7.
A growing number of β-lactamases have been reported in Pseudomonas aeruginosa clinical isolates. The aim of this study was to investigate the diversity of β-lactamases in the collection of 51 ceftazidime-resistant P. aeruginosa clinical isolates in four hospitals of southern China. Among these isolates, variable degrees of resistance to other β-lactam and non-β-lactam agents were observed. Pulsed-field gel electrophoresis (PFGE) revealed a high degree of clonality with five main genotypes. Of the 51 isolates tested, 35 (68.6%) were identified as extended-spectrum β-lactamase (ESBL) producers, with 35 producing PER-1, 1 CTX-M-3, 7 CTX-M-15 and 1 CTX-M-14. Most (82.9%, 29/35) PER-1-producing isolates were collected from two hospitals between January and April in 2008 and belonged to the same PFGE pattern (pattern B) with similar antibiogram and β-lactamase profiles, which suggested an outbreak of this clone at the time. The prevalence of CTX-M-type ESBL (17.6%, 9/51) was unexpectedly high. One isolate was identified as producing VIM-2. Furthermore, we also reported an occurrence of a novel OXA-10 variant, OXA-246, in 14 P. aeruginosa isolates. In addition, AmpC overproduction was found to be the β-lactamase-mediated mechanism responsible for ceftazidime resistance in 6 isolates (11.8%). Our results revealed an overall diversity of β-lactamases and outbreak of a PER-1-producing clone among ceftazidime-resistant P. aeruginosa in southern China.
越来越多的β-内酰胺酶已在铜绿假单胞菌临床分离株中被报道。本研究旨在调查来自中国南方四家医院的 51 株头孢他啶耐药铜绿假单胞菌临床分离株中β-内酰胺酶的多样性。在这些分离株中，观察到对其他β-内酰胺和非β-内酰胺类药物的不同程度的耐药性。脉冲场凝胶电泳（PFGE）显示出高度的克隆性，存在五种主要基因型。在测试的 51 株分离株中，35 株（68.6%）被鉴定为产超广谱β-内酰胺酶（ESBL），其中 35 株产生 PER-1，1 株产生 CTX-M-3，7 株产生 CTX-M-15，1 株产生 CTX-M-14。大多数（82.9%，29/35）产生 PER-1 的分离株是在 2008 年 1 月至 4 月期间从两家医院采集的，属于相同的 PFGE 模式（模式 B），具有相似的药敏谱和β-内酰胺酶谱，这表明当时该克隆发生了爆发。CTX-M 型 ESBL（17.6%，9/51）的流行率出乎意料地高。有 1 株分离株被鉴定为产生 VIM-2。此外，我们还报告了 14 株铜绿假单胞菌中新型 OXA-10 变体 OXA-246 的发生。另外，在 6 株（11.8%）头孢他啶耐药铜绿假单胞菌中发现了 AmpC 过度表达，这是β-内酰胺酶介导的头孢他啶耐药的机制。我们的结果显示，中国南方地区头孢他啶耐药铜绿假单胞菌中存在β-内酰胺酶的多样性和 PER-1 产生克隆的爆发。
