AAC：鉴别出一种新型耐药绿脓杆菌的金属β内酰胺酶类

一项来自锡耶纳大学等处研究者的研究揭示了其在意大利分离出的绿脓杆菌菌株中发现的一种新型的细菌获得性的金属β内酰胺酶类，名为FIM-1，相关研究成果“FIM-1， a new acquired metallo-β-lactamase from a Pseudomonas aeruginosa clinical isolate from Italy”刊登于国际杂志Antimicrobial Agents and Chemotherapy上。

绿脓杆菌是一种革兰氏阴性机会致病菌，其是医院内常见的引发慢性感染和急性感染的致病菌，严重者可引发患者肺部功能衰竭以及纤维化囊肿。获得性的金属β-内酰胺酶类（MBLs）是增加革兰氏阴性致病菌耐药性的主要决定因素，其通常含有一个广谱的β内酰胺类抗生素抗性，包括碳青霉烯类抗生素。

这项研究中，研究者发现了一种新型的MBL，名为FIM-1。研究者从意大利一位血管移植感染病人机体中分离到了一株临床的绿脓杆菌菌株。FIM-1酶获得性的MBLs家族中亚家族B1的一个成员，其与NDM酶类具有高度的相似性。

研究者Gian Maria Rossolini说，我们可以使用两种色谱法从大肠杆菌中纯化出蛋白质FIM-1，通过对纯化出的蛋白质进行动力学参数分析，可以揭示，FIM-1具有广谱的底物特异性，而且其更易于分解青霉素类以及碳青霉烯类抗生素。但是不会对氨曲南进行分解。

绿脓杆菌临床菌株中分离出的新型MBL对于研究者了解细菌耐药性、耐药性的多样性及日益增加的耐药性可以提供帮助，而且开发新型地抵御耐药细菌的疗法也提供了希望和研究基础。

doi:10.1128/​AAC.01953-12
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FIM-1, a new acquired metallo-β-lactamase from a Pseudomonas aeruginosa clinical isolate from Italy

Simona Pollinia, Simona Maradeia, Patrizia Pecileb, Giuseppe Olivoc, Francesco Luzzarod, Jean-Denis Docquiera and Gian Maria Rossolinia,e,#

Acquired metallo-β-lactamases (MBLs) are resistance determinants of increasing clinical importance in Gram-negative bacterial pathogens, which confer a broad-spectrum β-lactam resistance including carbapenems. Several such enzymes have been described since the 1990s. In this work a novel acquired MBL, named FIM-1, was identified and characterized. The blaFIM-1 gene was cloned from a multidrug-resistant Pseudomonas aeruginosa clinical isolate (FI-14/157) cultured from a patient with a vascular graft infection in Florence, Italy. The isolate belonged in the sequence type 235 epidemic clonal lineage. The FIM-1 enzyme is a member of subclass B1 and, among acquired MBLs, exhibited the highest similarity (around 40% amino acid identity) with NDM-type enzymes. In P. aeruginosa FI-14/157 the blaFIM-1 gene was apparently inserted into the chromosome and associated with ISCR19-like elements that were likely involved in the capture and mobilization of this MBL gene. Transfer experiments of the blaFIM-1 gene to an Escherichia coli or another P. aeruginosa strain by conjugation or electrotransformation were not successful. The FIM-1 protein was produced in Escherichia coli and purified by two chromatography steps. Analysis of the kinetic parameters, carried out with the purified enzyme, revealed that FIM-1 has a broad substrate specificity, with preference for penicillins (except the 6α-methoxy derivative temocillin) and carbapenems. Aztreonam was not hydrolyzed. Detection of this novel type of acquired MBL in a P. aeruginosa clinical isolate underscores the increasing diversity of such enzymes that can be encountered in the clinical setting.

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