Molecular characterization of an epidemic clone of panantibiotic-resistant Pseudomonas aeruginosa
Molecular characterization of an epidemic clone of panantibiotic-resistant Pseudomonas aeruginosa
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DOI：
10.1128/jcm.43.3.1198-1204.2005
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发表时间：
2005-03-01
影响因子：
9.4
通讯作者：
Struelens, MJ
中科院分区：
文献类型：
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作者：
Deplano, A;Denis, O;Struelens, MJ
我们描述了一个多重耐药铜绿假单胞菌克隆的分子特征，该克隆引起了一所大学三级护理医院重症监护室（ICU）的爆发。分析包括抗菌药物敏感性，O-血清分型，脉冲场凝胶电泳，扩增片段长度多态性。耐药机制的特点，包括生产天然存在的和收购β-内酰胺酶，孔蛋白表达，和外排泵系统。18例患者定植或感染多重耐药铜绿假单胞菌。多重耐药铜绿假单胞菌对青霉素类、头孢菌素类、碳青霉烯类、氨基糖苷类和氟喹诺酮类部分耐药，仅对粘菌素敏感。16株（89%）为O：11血清型、脉冲场凝胶电泳A1型和扩增片段长度多态性A型。该流行性克隆的耐药性特征显示染色体头孢菌素酶AmpC的过表达结合孔蛋白OprD的表达降低和金属β-内酰胺酶或超广谱β-内酰胺酶的缺乏。检测到由于mexZ阻遏物中的agrZ突变导致的MexXY外排系统的上调。这种流行性克隆仅限于ICU，在医院其他地方没有发现。重症监护室环境和重症监护室护士的手受到这种克隆的污染，表明可能存在手传播。实施接触预防措施有效地控制了流行性克隆的传播。这项研究说明了多重耐药铜绿假单胞菌引起具有显著发病率和死亡率的爆发的能力，并强调了识别克隆爆发的必要性，这需要有针对性的感染控制措施。
We describe the molecular characterization of a multiresistant Pseudomonas aeruginosa clone causing an outbreak in the intensive care unit (ICU) of a tertiary-care university hospital. Analysis included antimicrobial susceptibility profile, O-serotyping, pulsed-field gel electrophoresis, and amplified fragment length polymorphism. Resistance mechanisms were characterized, including production of naturally occurring and acquired beta-lactamases, porin expression, and efflux pump systems. Eighteen patients were colonized or infected with multiresistant P. aeruginosa. Multiresistant P. aeruginosa was partresistant to penicillins, cephalosporins, carbapenems, aminoglycosides, and fluoroquinolones and remained susceptible only to colistin. Sixteen isolates (89 %) belonged to serotype O:11, pulsed-field gel electrophoresis type A1, and amplified fragment length polymorphism type A. Resistance characterization of this epidemic clone showed an overexpression of the chromosomal cephalosporinase AmpC combined with decreased expression of porin OprD and the absence of metallo-beta-lactamase or extended-spectrum beta-lactamase. An upregulation of the MexXY efflux system due to an agrZ mutation in the mexZ repressor was detected. This epidemic clone was restricted to the ICU and was not found elsewhere in hospital. Contamination of the ICU environment and the hands of an ICU nurse with this clone suggests possible hand-borne transmission. Implementation of contact precautions effectively controlled transmission of the epidemic clone. This study illustrates the ability of multiresistant P. aeruginosa to cause an outbreak with significant morbidity and mortality and underscores the need to identify clonal outbreaks, which require targeted infection control measures.